A systematic appraisal of allegiance effect in randomized controlled trials of psychotherapy Estimating the Horizon of Articles to Decide When to Stop Searching in Systematic Reviews: An Example Using a Systematic Review of RCTs Evaluating Osteoporosis Clinical Decision Support Tools Mineral Trioxide Aggregate vs. Calcium Hydroxide in Primary Molar Pulpotomy: A Systematic Review A systematic review of anxiety interventions in stroke and acquired brain injury: Efficacy and trial design A simplified search strategy for identifying randomised controlled trials for systematic reviews of health care interventions: a comparison with more exhaustive strategies Dietetic guidelines: diet in secondary prevention of cardiovascular disease. Comparative Effectiveness of Dipeptidylpeptidase-4 Inhibitors in Type 2 Diabetes: A Systematic Review and Mixed Treatment Comparison Effectiveness of workplace interventions in rehabilitating musculoskeletal disorders and preventing its consequences among workers with physical and sedentary employment: systematic review protocol Treatment of Blood Cholesterol to Reduce Atherosclerotic Cardiovascular Disease Risk in Adults: Synopsis of the 2013 American College of Cardiology/American Heart Association Cholesterol Guideline Statins for Primary Prevention: The Debate Is Intense, but the Data Are Weak. How Quickly Do Systematic Reviews Go Out of Date? A Survival Analysis How effective and safe is medical cannabis as a treatment of mental disorders? A systematic review Sources of evidence for systematic reviews of interventions in diabetes. Antimicrobially impregnated catheters: An overview of randomized controlled trials. Systematic review automation technologies Randomized controlled trials of aprotinin in cardiac surgery: could clinical equipoise have stopped the bleeding? Indirect comparisons of competing interventions. Can we rely on the best trial? A comparison of individual trials and systematic reviews Systematic reviews in endodontics--examples of GIGO? Effect of vitamin D supplementation on inflammation: protocol for a systematic review Comparison of large versus smaller randomized trials for mental health-related interventions. A systematic review protocol examining the effect of vitamin D supplementation on endothelial function A systematic review of randomized controlled trials on curative and health enhancement effects of forest therapy
Background Experimenter ’s allegiance ( EA ) refers to a personal confidence of the superiority of a specific psychotherapy treatment . This factor has been linked with larger treatment effects in favor of the preferred treatment . However , various studies have displayed contradictory results between EA and the pattern of treatment effects . Aims Using a systematic approach followed by meta- analysis , we aim ed to evaluate the impact of an allegiance effect on the results of psychotherapeutic studies . Method We considered the meta-analyses of r and omized controlled trials ( RCTs ) of different types of psychotherapies in the Cochrane Data base of Systematic Review s. Eligible articles included meta-analyses of RCTs with at least one study showing evidence of EA ( i.e. , allegiant study ) . Effect sizes in allegiant RCTs were compared with non-allegiant using r and om and fixed models and a summary relative odds ratio ( ROR ) were calculated . Heterogeneity was quantified with the I2 metric . Results A total of 30 meta-analyses including 240 RCTs were analyzed . The summary ROR was 1.31 [ ( 95 % confidence interval ( CI : 1.03–1.66 ) P = 0.30 , I2 = 53 % ] indicating larger effects when allegiance exists . The impact of allegiance did not differ significantly ( P > 0.05 ) when we compared psychiatric versus medical outcomes . Allegiance effect was significant for all forms of psychotherapy except for cognitive behavioral therapy . Moreover , the impact of allegiance was significant only when the treatment integrity of delivered psychotherapy was not assessed . Allegiance effect was even stronger where the experimenter was also both the developer of the preferred treatment and supervised or trained the therapists . No significant differences were found between allegiant and non-allegiant studies in terms of overall quality of studies . Conclusions Experimenter ’s allegiance influences the effect sizes of psychotherapy RCTs and can be considered non-financial conflict of interest introducing a form of optimism bias , especially since blinding is problematic in this kind of research . A clear reporting of EA in every single study should be given an opportunity to investigators of minimizing its overestimation effects Research ers conducting systematic review s need to search multiple bibliographic data bases such as MEDLINE and EMBASE . However , research ers have no rational search stopping rule when looking for potentially-relevant articles . We empirically tested a stopping rule based on the concept of  capture-mark-recapture ( CMR ) , which was first pioneered in ecology . The principles of CMR can be adapted to systematic review s and meta-analyses to estimate the Horizon of articles in the literature with its confidence interval . We retrospectively tested this Horizon Estimation using a systematic review of r and omized controlled trials ( RCTs ) that evaluated clinical decision support tools for osteoporosis disease management . The Horizon Estimation was calculated based on 4 bibliographic data bases that were included as the main data sources for the review in the following order : MEDLINE , EMBASE , CINAHL , and EBM Review s. The systematic review captured 68 % of known articles from the 4 data sources , which represented 592 articles that were estimated as missing from the Horizon Introduction : The aim of this quantitative systematic review /meta- analysis was to compare the treatment outcomes of mineral trioxide aggregate ( MTA ) and calcium hydroxide ( CH ) in pulpotomy of human primary molars . The focused PICO question was “ in case of pulp exposure in vital primary molars , how does MTA pulpotomy compare to CH in terms of clinical /radiographic success ? ” Methods and Material s : We retrieved published r and omized clinical trials ( RCTs ) of at least 6-month duration ; our search included articles published up to March 2013 in five following data bases : PubMed ( Medline ) , Cochrane data base of systematic review s , Science Citation Index , EMBASE , and Google Scholar . Mantel Haenszel and Inverse Variance-weighted methods were applied by STATA ; the relative risk ( RR ) was calculated with 95 % confidence intervals ( CI ) . Results : A total of 282 English articles were collected . Two authors independently screened the articles and five RCTs were selected ; data extraction and quality assessment were then carried out . Four RCTs were appropriate for meta- analysis according to their follow-up times by Mantel Haenszel method . Statistically significant difference was found between success rate of MTA compared to CH , with RR=0.08 ( 95 % CI , 0.02 - 0.39 ) , RR=0.19 ( 95 % CI , 0.08 - 0.46 ) , and RR=0.38 ( 95 % CI , 0.21 - 0.68 ) for 6- , 12- , and 24-month follow-ups , respectively . A significant difference was also observed for all included RCTs after analyses using the Inverse Variance-weighted method ( RR=0.44 ; 95 % CI , 0.27 - 0.72 ) . Conclusions : Systematic review /meta- analysis of included RCTs revealed that for pulpotomy of vital primary molars , MTA has better treatment outcomes compared to CH Objective There is little r and omized controlled trial ( RCT ) evidence to guide treatment for anxiety after stroke . We systematic ally review ed RCTs of anxiety interventions in acquired brain injury ( ABI ) conditions including stroke and traumatic brain injury ( TBI ) in order to summarize efficacy and key aspects of trial design to help guide future RCTs . Methods We search ed the Cochrane trial register , Medline , Embase , PsychInfo and CINAHL systematic ally up to August 2017 . Two independent review ers systematic ally selected studies and extracted data . We summarized the effect size , key study characteristics and sources of potential bias in trial design . Results 14 studies ( 12 stroke ; one stroke & TBI ; one TBI ) with 928 participants were included . Meta- analysis of five psychotherapy comparisons favoured intervention over control ( st and ardized mean difference ( SMD ) : − 0.41 [ − 0.79 , − 0.03 ] , I2 = 28 % ) ; Overall effect size of pharmacotherapy comparisons favoured intervention over control ( SMD : − 2.12 [ − 3.05 , − 1.18 ] , I2 = 89 % ) . One comparison of mixed pharmacotherapy and psychotherapy favoured intervention over usual care ( SMD : − 4.79 [ − 5.87 , − 3.71 ] ) . One comparison favoured  forest therapy versus urban control ( SMD : − 2.00 [ − 2.59 , − 1.41 ] ) . All positive studies carried high or unclear risk of bias . Sample sizes were small in all included studies . Conclusions There is low quality evidence to suggest that psychotherapy and pharmacotherapy may be effective interventions in the treatment of anxiety after stroke based on underpowered studies that carried high risk of bias . Large-scale well- design ed definitive trials are needed to establish whether pharmacological or psychotherapy works . Our review highlighted key considerations for investigators wishing to design high quality trials to evaluate treatments for anxiety after stroke Background It is generally believed that exhaustive search es of bibliographic data bases are needed for systematic review s of health care interventions . The CENTRAL data base of controlled trials ( RCTs ) has been built up by exhaustive search ing . The CONSORT statement aims to encourage better reporting , and hence indexing , of RCTs . Our aim was to assess whether developments in the CENTRAL data base , and the CONSORT statement , mean that a simplified RCT search strategy for identifying RCTs now suffices for systematic review s of health care interventions . Methods RCTs used in the Cochrane review s were identified . A brief RCT search strategy ( BRSS ) , consisting of a search of CENTRAL , and then for variants of the word r and om across all fields ( r and om$.af . ) in MEDLINE and EMBASE , was devised and run . Any trials included in the meta-analyses , but missed by the BRSS , were identified . The meta-analyses were then re-run , with and without the missed RCTs , and the differences quantified . The proportion of trials with variants of the word r and om in the title or abstract was calculated for each year . The number of RCTs retrieved by search ing with " r and om$.af . " was compared to the highly sensitive search strategy ( HSSS ) . Results The BRSS had a sensitivity of 94 % . It found all journal RCTs in 47 of the 57 review s. The missing RCTs made some significant differences to a small proportion of the total outcomes in only five review s , but no important differences in conclusions result ed . In the post-CONSORT years , 1997–2003 , the percentage of RCTs with r and om in the title or abstract was 85 % , a mean increase of 17 % compared to the seven years pre-CONSORT ( 95 % CI , 8.3 % to 25.9 % ) . The search using r and om$.af . reduced the MEDLINE retrieval by 84 % , compared to the HSSS , thereby reducing the workload of checking retrievals . Conclusion A brief RCT search strategy is now sufficient to locate RCTs for systematic review s in most cases . Exhaustive search ing is no longer cost-effective , because in effect it has already been done for CENTRAL AIM To produce dietetic guidelines summarizing the systematic review evidence on dietary advice for secondary prevention of cardiovascular disease . METHODS The Cochrane Library , MEDLINE and EMBASE were comprehensively search ed for systematic review s on aspects of diet and heart health . Review s were included if they search ed systematic ally for r and omised controlled trials relating to diet and secondary prevention of cardiovascular disease . Two members of the UK Heart Health and Thoracic Dietitians Group critically appraised each review . The quality and results of each review were discussed and summarized in a whole group meeting . The guidelines were trialled in seven dietetic departments and modified where necessary . RESULTS Providing evidence -based dietary information ( including increasing omega-3 fat plus fruit and vegetable intake ) to all people after myocardial infa rct ion will save more lives than concentrating dietary advice on those in need of weight loss or lipid lowering . The practice of prioritizing dietetic time to those with raised lipids is out of date since the advent of statin therapy . CONCLUSION There is good systematic review evidence that dietary advice to those with cardiovascular disease can reduce mortality and morbidity as well as modify risk factors .  Dietary advice that does this most effectively should be prioritized Objective To compare the safety and efficacy of the dipeptidylpeptidase-4 ( DPP-4 ) inhibitors in patients with type 2 diabetes and inadequate glycemic control . Design Systematic review of r and omized controlled trials ( RCTs ) , health economic evaluation studies , systematic review s , and meta-analyses , followed by primary Bayesian mixed treatment comparison meta-analyses ( MTCs ) , and secondary frequentist direct-comparison meta-analyses using a r and om-effects model . Outcomes were reported as weighted mean change from baseline , or odds ratio ( OR ) with 95 % credible interval . Data sources MEDLINE , MEDLINE In-Process , EMBASE , and BIOSIS via Dialog ProQuest ; Cochrane Central Register of Controlled Trials and Cochrane Data base of Systematic Review s via EBSCO ; four diabetes and two technical congress abstract s ; and health technology assessment organization websites . Eligibility criteria Patients with type 2 diabetes and inadequate glycemic control receiving any pharmacological anti-diabetic treatment . Data extraction and analysis Title/ abstract s were review ed for eligibility , followed by full-text review of publications remaining after first pass . A three-person team filtered articles and an independent review er checked a r and om selection ( 10 % ) of filtered articles . Data extraction and quality assessment of studies were also independently review ed . Five DPP-4 inhibitors ( alogliptin , linagliptin , saxagliptin , sitagliptin , and vildagliptin ) were compared via meta- analysis ( where data were available ) as monotherapy , dual therapy ( plus metformin , sulfonylurea , pioglitazone , or insulin ) , and triple therapy ( plus metformin/sulfonylurea ) . Results The review identified 6,601 articles ; 163 met inclusion criteria and 85 publications from 83 RCTs contained sufficient or appropriate data for analysis . MTCs demonstrated no differences between DPP-4 inhibitors in mean change from baseline in glycosylated hemoglobin ( HbA1c ) or body weight , or the proportions of patients achieving HbA1c < 7 % or experiencing a hypoglycemic event , apart from in patients on alogliptin plus metformin , who achieved HbA1c < 7 % more frequently than those treated with saxagliptin plus metformin [ OR 6.41 ( 95 % CI 3.15–11.98 ) versus 2.17 ( 95 % CI 1.56–2.95 ) ] . Conclusions This systematic review and MTC showed similar efficacy and safety for DPP-4 inhibitors as treatment for type 2 diabetes , either as monotherapy or combination therapy Background Musculoskeletal disorders ( MSDs ) are the leading cause of work disability and sickness absence worldwide . The prevalence of MSDs increases with age , consequently challenging sustainable employability among the growing ageing workforce . Knowledge of feasible and efficient workplace-based interventions to rehabilitate MSD or prevent its consequences is therefore warranted . This systematic review will evaluate the effectiveness of workplace-based interventions on MSDs and its consequences among adult workers with physical and sedentary work tasks , respectively . Methods We will search the following bibliographic data bases : PubMed ( including the data base ‘ MEDLINE ’ ) and Web of Science Core Collection ( including the data bases ‘ Science Citation Index Exp and ed ’ , ‘ Social Sciences Citation Index ’ and ‘ Arts & Humanities Citation Index ’ ) . Manual search es will also be performed . We will include r and omised controlled trials ( RCTs ) and non- RCTs reported in English in which ( 1 ) participants are adult workers with MSD , ( 2 ) interventions are aim ing at rehabilitating pain symptoms of MSD or preventing the consequences of MSD and ( 3 ) interventions are initiated and /or carried out at the workplace . The review will adhere to the ‘ Preferred Reporting Items for Systematic review s and Meta-Analyses ’ ( PRISMA ) guidelines for reporting systematic review s and the Institute for Work and Health ( IWH ) guidelines for workplace-based interventions . For the primary evaluation of the review , the quality assessment and evidence synthesis will conform to the IWH guidelines . Secondary evaluation will include a meta- analysis ( unless the included studies do not allow this due to heterogeneity ) and employ the risk of bias domains recommended by Cochrane along with the Grading of Recommendations , Assessment , Development and Evaluations ( GRADE ) approach on the studies with pain intensity as an outcome . Discussion This systematic review will provide knowledge on effective workplace-based interventions among physical and sedentary workers with MSD . RCTs are considered the most powerful experimental design in clinical trials , but solely including these may be too restrictive to underst and effective workplace-based interventions where r and omised and carefully controlled trials ( RCTs ) are not always possible . In order to maximize practical relevance , the selection process will , therefore , include both RCTs and non- RCTs and the quality assessment and evidence synthesis will conform to IWH guidelines focusing on developing practical guidelines for stakeholders . The result of this work will form the basis for industry-specific evidence -based recommendations on effective workplace-based interventions for rehabilitation of MSDs and its consequences that will later be operationalised into concrete and user-friendly practical tools for workplaces . Systematic review registration International Prospect i ve Register of Systematic Review s ( PROSPERO ) number CRD42018116752 Atherosclerotic cardiovascular disease ( ASCVD ) is the leading cause of death , decreased quality of life , and medical costs in the United States . Nearly 1 in 3 Americans die of heart disease and stroke ( 1 ) . Most ASCVD is preventable through a healthy lifestyle and effective treatment of cholesterol and blood pressure . The 2013 Guideline on the Treatment of Blood Cholesterol to Reduce Atherosclerotic Cardiovascular Risk in Adults from the American College of Cardiology and American Heart Association ( ACC/AHA ) provides an evidence -based approach to reducing ASCVD risk ( 2 ) . Guideline Development Process In 2008 , the National Heart , Lung , and Blood Institute ( NHLBI ) convened the Adult Treatment Panel ( ATP ) IV to up date the 2001 ATP-III cholesterol guidelines using a rigorous systematic process to identify and review r and omized , controlled trials ( RCTs ) with cardiovascular outcomes and meta-analyses of these RCTs . The panel comprised experts and clinicians from the fields of cardiology , epidemiology , primary care , and endocrinology ( 2 ) and received support from the Lifestyle Management and Risk Assessment Work Groups ( 3 , 4 ) . Systematic evidence review s conducted according to principles recommended by the Institute of Medicine ( 5 ) were performed to answer 3 questions relevant to clinical care . Two questions focused on the evidence supporting low-density lipoprotein cholesterol ( LDL-C ) and nonhigh-density lipoprotein cholesterol ( HDL-C ) levels as targets of treatment . One question examined the reduction in ASCVD events and adverse effects for each cholesterol-lowering drug class . The panel synthesized the evidence from these 3 review s as well as from Lifestyle Management and Risk Assessment Work Groups review s ( 3 , 4 ) that addressed 5 additional critical questions . Systematic electronic search es of relevant data bases of the peer- review ed English- language literature published from 1 January 1995 through 1 December 2009 for each critical question were conducted by an NHLBI-selected independent contractor and focused on RCTs and systematic review s and meta-analyses of RCTs assessed as fair to good quality . In addition , RCTs with ASCVD outcomes that included coronary heart disease , stroke , and cardiovascular deaths published after that date were eligible for consideration through July 2013 . Evidence tables were constructed , and the strength of evidence was rated according to the NHLBI ( Table 1 of the Supplement ) . Recommendations were grade d according to criteria from the NHLBI ( Table 2 of the Supplement ) and ACC/AHA ( Table 3 of the Supplement ) . Because of the inherent differences in grading systems and the clinical questions driving the recommendations , alignment between the NHLBI and ACC/AHA formats was imperfect . A complete description of the methods used and results of the evidence review are provided in the guideline ( 2 ) and the NHLBI evidence report ( www.nhlbi.nih.gov/ guidelines /cholesterol/ser/index.htm ) . Supplement . NHLBI and ACC/AHA Criteria for Rating Strength of Evidence To help clinicians estimate ASCVD risk , the risk assessment working group developed the Pooled Cohort Equations using data from 5 NHLBI-sponsored longitudinal , population -based cohorts of African American and non-Hispanic white men and women to estimate risk for a first myocardial infa rct ion , coronary heart disease death , or fatal or nonfatal stroke on the basis of age , sex , race , smoking status , total cholesterol level , HDL-C level , systolic blood pressure , antihypertensive therapy , and diabetes ( 4 , 6 ) . These equations significantly advance ASCVD risk estimation by providing sex- and race-specific estimates and including stroke as an outcome . The earlier Framingham equations calculated only coronary heart disease risk for non-Hispanic whites . The draft recommendations were review ed by 23 experts and representatives of federal agencies identified by the NHLBI . In September 2013 , the recommendations developed by the panel were transitioned to the ACC/AHA and had additional review by 4 experts nominated by the ACC Foundation and the AHA . The governing bodies of the ACC and AHA approved the guideline , which also received endorsement from the American Association of Cardiovascular and Pulmonary Rehabilitation , American Pharmacists Association , American Society for Preventive Cardiology , Association of Black Cardiologists , Preventive Cardiovascular Nurses Association , and WomenHeart : The National Coalition for Women with Heart Disease . Recommendations The guideline focuses on treatment of blood cholesterol to reduce ASCVD risk in adults . Major recommendations are summarized here and in Table 1 . The guideline report provides a complete listing of recommendations and supporting evidence behind each recommendation ( 2 ) . Table 1 . Major Recommendations for the Treatment of Blood Cholesterol to Reduce ASCVD Risk in Adults * 1 . Encourage Adherence to a Healthy Lifestyle A healthy lifestyle is the foundation for cardiovascular health . The panel endorsed the 2013 ACC/AHA Lifestyle Management Guideline ( 3 ) for a diet that is low in saturated fat , trans fat , and sodium ; emphasizes vegetables , fruits , whole grains , low-fat dairy products , poultry , fish , legumes , nontropical vegetable oils , and nuts ; and limits sweets , sugar-sweetened beverages , and red meats and engage in regular aerobic physical activity . Adults also should maintain a healthy body weight , avoid smoking , and control hypertension and diabetes when present . 2 . Statin Therapy Is Recommended for Adults in Groups Demonstrated to Benefit Strong RCT evidence shows that reduction in ASCVD events from statin therapy exceeds adverse events for 4 patient groups : those with clinical ASCVD ( acute coronary syndromes , myocardial infa rct ion , stable angina , coronary or other arterial revascularization , stroke , transient ischemic attack , or peripheral arterial disease of atherosclerotic origin ) when  statins are used for secondary prevention , and those with LDL-C levels 190 mg/dL ; those aged 40 to 75 years with diabetes and LDL-C levels 70 to 189 mg/dL ; and those aged 40 to 75 years without diabetes and with a 10-year ASCVD risk 7.5 % when statins are used for primary prevention . Moderate evidence supports consideration of statin therapy for primary prevention in individuals with a 10-year ASCVD risk of 5 % to < 7.5 % . Routine initiation of statin therapy is not recommended in adults with New York Heart Association heart failure class II to IV or those receiving maintenance hemodialysis . R and omized , controlled trials in these groups showed no reduction in ASCVD . 3 . Statins have an Acceptable Margin of Safety When Used in Properly Selected Individuals and Appropriately Monitored Strong RCT evidence supports safety of statins when they are used as directed in conjunction with regular follow-up assessment s in properly selected patients . Adjustment of statin intensity is recommended in individuals older than 75 years with a history of statin intolerance or other characteristics ( 2 ) or those receiving drug therapy that may increase statin adverse events . Routine monitoring of hepatic aminotransferase level or creatine kinase level is not recommended unless clinical ly indicated by symptoms suggesting hepatotoxicity or myopathy . Given the potential for decreasing ASCVD events and death , the relationship of muscle and other symptoms to statin treatment must be confirmed . Therefore , eliciting a history of muscle symptoms before statin initiation and carefully monitoring symptoms during statin discontinuation and rechallenge is recommended . Severe myopathy , rhabdomyolysis , and possibly hemorrhagic stroke are rare complications of statin therapy . Although statin therapy modestly increases the risk for type 2 diabetes , ASCVD risk reduction outweighs the excess risk for diabetes for high-intensity statins in secondary prevention or for 10-year ASCVD risk 7.5 % . Similarly , ASCVD risk reduction outweighs the excess risk for diabetes for moderate-intensity statin therapy in adults with a 10-year ASCVD risk 5 % . 4 . Engage in a ClinicianPatient Discussion Before Initiating Statin Therapy , Especially for Primary Prevention in Patients With Lower ASCVD Risk Decisions to initiate statin therapy in primary prevention should be based on clinical judgment and preferences of informed patients . In adults without clinical ASCVD or diabetes whose LDL-C level is < 190 mg/dL , calculating the estimated 10-year ASCVD risk should be the start of the clinicianpatient discussion and should not automatically lead to statin initiation . As the absolute risk for ASCVD events decreases , so does the net benefit of the intervention . Therefore , discussion of the potential for ASCVD event reduction , adverse effects , drugdrug interactions , and patient preferences is especially important for lower-risk primary prevention . The discussion provides the opportunity to encourage healthy lifestyle habits and control other risk factors . Additional factors may be considered when a risk-based decision is uncertain , including LDL-C levels 160 mg/dL , family history of premature ASCVD , elevated  lifetime ASCVD risk  , high-sensitivity C-reactive protein level 2.0 mg/L ,  coronary artery calcification score  > 300 Agatston units , and anklebrachial index < 0.9 . After age 75 years , comorbid conditions , anticipated longevity , safety considerations , and patient preferences should play a large role in decision making . 5 . Use the Newly Developed Pooled Cohort Equations for Estimating 10-Year ASCVD Risk The Pooled Cohort Equations are currently the best available method for estimating 10-year ASCVD risk to guide statin initiation ( 4 , 6 ) . Application of the inclusion and exclusion criteria from RCTs is cumbersome and results in underidentifying high-risk and overidentifying low-risk individuals for statin treatment . The Pooled Cohort Equations were developed using recent data from 5 NHLBI-sponsored , longitudinal , population -based cohorts of African American and white men and women ( ARIC [ This issue of JAMA contains the latest US Preventive Services Task Force ( USPSTF ) recommendation statement on statins for prevention of cardiovascular disease in adults,1 along with the accompanying evidence report and systematic review 2 on which the recommendations are based . The evidence report summarized data from 19 trials including a total of 71 344 patients and concluded that statin therapy was associated with reduced risk of all-cause and cardiovascular mortality and cardiovascular disease ( CVD ) events . Thus , the task force recommended “ initiating use of lowto moderate-dose statins in adults aged 40 to 75 years without a history of CVD who have 1 or more CVD risk factors and a calculated 10-year CVD event risk of 10 % or greater ( B recommendation ) ” or “ 7.5 % to 10 % ( C recommendation ) .”1 Although the task force did their usual careful job of review ing the evidence , the evidence for treating asymptomatic persons with statins does not appear to merit a grade B or even a grade C recommendation . The task force evidence report estimated an absolute benefit for use of statins of 0.40 % for all-cause mortality and 0.43 % for cardiovascular mortality and indicated that the absolute benefit was greater for patients at greater baseline risk.2 Notably , the evidence report did not exclude studies that included patients taking statins for secondary prevention , who have a higher baseline risk of cardiac events and death and thus are more likely to benefit from therapy that inflates the benefit attributed to a primary prevention population . The task force did perform a sensitivity analysis that excluded 3 trials with persons for whom there were prior “ hard ” cardiovascular events and obtained similar results of benefits ( eTable 5 in the article by Chou et al2 ) . This sensitivity analysis did not exclude WOSCOPS , which included patients receiving statins for secondary prevention—5 % had angina and 3 % had intermittent claudication,3 accounting for 15 % of the total weight in the meta- analysis . In contrast , a meta- analysis of 11 studies and 65 229 patients receiving statins for primary prevention , in which patients receiving statins for secondary prevention were excluded , found no benefit of statins for reducing all-cause mortality.4 The confidence intervals of these 2 analyses overlap , and the difference between these findings likely reflects differences in studies included . The USPSTF and authors of the evidence report did not have access to the primary data ( clinical study reports and anonymized patient-level data ) from the statin clinical trials . Rather , they had to rely on peer- review ed published reports as the basis for these recommendations . Exacerbating the potential bias , all of the trials included in the task force evidence report2 were industry-sponsored except 1 trial,5 and that trial contributed 0.2 % of the weight to the mortality calculation . Industry-sponsored studies have been shown to report greater benefit and lesser adverse effects than noncommercially sponsored trials of the same drugs.6 Whether this is true for statins and primary prevention of CVD is unknown . Among the 19 r and omized clinical trials of statins vs placebo or no statin included in the evidence report for the task force recommendations , only 15 reported all-cause mortality , 10 reported cardiovascular mortality , 12 reported fatal and nonfatal myocardial infa rct ion  , and 13 reported fatal and nonfatal stroke.2,7  Reliance on selective reporting of the most important outcomes , which are likely included in the clinical trial data , makes reporting bias possible . Furthermore , after allcause mortality , the comparative incidence of serious adverse events between treatment and control groups is arguably the second most important measure of the effect of active therapy in r and omized clinical trials . Underst and ing the evidence base in evaluating harms of statin therapy is also critically important . Although the benefits of any preventive therapy accrue according to risk of disease ( greater benefit in higher-risk patients ) , the harms of therapy usually distribute equally over all risk levels . Thus , persons at low risk have little chance of benefit but equal chance of harms and thus are more likely to have a net harm . The evidence base for harms of statins , despite the introduction of these drugs more than 20 years ago , is incomplete . Many of the trials did not ask about commonly reported statin effects , such as muscle pains and weakness , and only recorded myopathy , for which an increase in creatine kinase levels was required . Because most muscle problems do not involve an increase in creatine kinase levels , this leads to a significant underestimate of muscle problems . Other studies have estimated that closer to 20 % of statin users have muscle problems.8 Additionally , the actual trial data are largely held by the Cholesterol Treatment Trialists ’ Collaboration on behalf of the industry sponsor and have not been made available to other research ers , despite multiple requests over many years.9 Although reported rates of adverse events in clinical trials are low , this does not reflect the experience of clinicians who see patients who are taking statins . For instance , the experience of an NPR reporter with a calculated 2.9 % risk of heart disease over 10 years using the recommended American College of Cardiology/American Heart Association ( ACC/AHA ) risk calculator,10 but still prescribed a statin , and experiencing adverse effects from the medication , is typical of what many Related articles at jama.com Context Clinicians rely on systematic review s for current , evidence -based information . Contribution This survival analysis of 100 meta-analyses indexed in ACP Journal Club from 1995 to 2005 found that new evidence that substantively changed conclusions about the effectiveness or harms of therapies arose frequently and within relatively short time periods . The median survival time without substantive new evidence for the meta-analyses was 5.5 years . Significant new evidence was already available for 7 % of the review s at the time of publication and became available for 23 % within 2 years . Implication Clinical ly important evidence that alters conclusions about the effectiveness and harms of treatments can accumulate rapidly . The Editors Systematic review s have become increasingly common in recent years ( 1 ) and are recommended by many as the best sources of evidence to guide both clinical decisions ( 2 ) and health care policy ( 3 ) . For systematic review s to fulfill these roles , their findings must remain relatively stable for at least several years or effective mechanisms must exist for alerting end users to important changes in evidence . Yet , surprisingly little research has assessed the extent to which systematic review s become out of date or the rate at which this occurs ( 47 ) . Some organizations , such as the Cochrane Collaboration , recommend updating systematic review s every 2 years , but few empirical data guide this or other recommendations about updating . We sought to determine how quickly systematic review s meet explicitly defined criteria for changes in evidence of sufficient importance to warrant updating . We also sought to identify predictors of survival time , the time to such important changes in evidence . Survival time might vary depending on many factors , including the type of question posed by the original review ( for example , therapeutic or diagnostic ) , the types of studies included ( for example , r and omized trials or observational studies ) , and whether the systematic review provided quantitative synthesis . To limit such variation , we focused on systematic review s of r and omized , controlled trials that evaluated therapeutic benefit or harm by providing quantitative synthesis ( meta- analysis ) for at least 1 outcome . Methods Study Design and Sample We used a quasi-r and om process ( alphabetical sort order by author ) to select 100 systematic review s that were indexed in ACP Journal Club with an accompanying commentary between January 1995 and December 2005 ( with a search date no later than 31 December 2004 to ensure at least 1 full year for new evidence to appear ) . We chose this sampling frame because ACP Journal Club selects systematic review s that meet explicit quality st and ards and are deemed directly relevant to clinical practice ( 8) . We regarded the sample size of 100 as sufficiently large to achieve suitably narrow confidence intervals and to permit evaluation of up to 5 potential predictors of survival . Eligibility Criteria Eligible review s evaluated the benefit or harm of a specific drug , class of drug , device , or procedure ( invasive procedure or surgery ) and included r and omized or quasi-r and omized , controlled trials . We excluded evaluations of alternative and complementary medicines because the stability of review s of such therapies might differ substantially from review s of conventional therapies . We required that review s provide a point estimate and 95 % confidence interval for at least 1 outcome in the form of a relative risk , odds ratio , or absolute risk difference for binary outcomes and weighted mean differences for continuous outcomes . We excluded meta-analyses of individual-patient data , meta-regressions , and indirect meta-analyses because of the difficulty of determining whether new data would alter previous quantitative results . Two team members independently assessed eligibility , with disagreements resolved by consensus involving a third review er . When more than 1 review on the same topic was identified , only the earliest was included . Search ing For each review , search es for new trials included identifying new systematic review s on the same topic , su bmi tting relevant content terms to the Clinical Queries function in Ovid , applying the Related Articles function in PubMed to the 3 largest and the 3 most recent trials in the original review ( up to 6 trials in total ) , and using Scopus ( www . scopus .com/ scopus /home.url ) to identify new r and omized trials that cited the original review . When these search strategies yielded no eligible new trials , we conducted more comprehensive electronic search es and review ed relevant chapters in such sources as Clinical Evidence and UpTo Date to ensure that we had not missed new trials . Team members who had background s in both medicine and clinical research screened citations retrieved by the preceding methods to identify trials that would have met the inclusion criteria in the original review . Retrieved articles were screened in chronological order to ascertain quantitative or qualitative signals for the need for updating . The review protocol stopped when any criteria for updating were met . Each systematic review was discussed in detail , with the final statussignal for updating was or was not detectedadjudicated by consensus ( Figure 1 ) . Figure 1 . Overall process for determining updating status . ACP Journal Club Signals for the Need to Up date Systematic Review s In design ing criteria for comparing new findings with those in a previous review , we adapted methods used by other investigators to address similar problems with comparing 2 sets of results relating to the same question ( 913 ) , such as r and omized and nonr and omized studies of the same intervention . These investigators identified conflicting findings among different publications using a combination of quantitative thresholds for differences in effect magnitude and qualitative judgments about the language used to describe the results . We have similarly conceptualized quantitative and qualitative signals of potential changes in evidence that are sufficiently important to warrant updating previous systematic review s. Quantitative Signals Quantitative signals consisted of a change in statistical significance or relative change in effect magnitude of at least 50 % . We restricted these changes to those involving 1 of the primary outcomes of the original review or any mortality outcome . We also ignored trivial changes in statistical significance when the original and up date d meta-analytic results both had P values between 0.04 and 0.06so that quantitative signals of changes in evidence would represent robust indicators of the need to up date previous review s. Quantitative signals were detected by combining data from eligible new trials with the previous results using a fixed-effects approach . Use of fixed-effect models allowed pooling of the new trials with the previous meta-analytic result , as opposed to having to obtain original data from all of the included trials in each of 100 systematic review s. Although r and om-effects models are usually preferred to avoid spurious precision in the face of heterogeneity , our goal was to detect potential changes in evidence that would warrant a formal up date , not produce exact estimates of the up date d results . Qualitative Signals Qualitative signals included new information about harm sufficient to affect clinical decision making , important caveats to the original results , emergence of a superior alternate therapy , and important changes in certainty or direction of effect . Qualitative signals were detected by using explicit criteria for comparing the language in the original review with descriptions of findings in new systematic review s that addressed the same topic , pivotal trials , clinical practice guidelines , or recent editions of major textbooks ( for example , UpTo Date ) . Pivotal trials were defined as trials that had a sample size at least 3 times larger than that of the previous largest trial or were published in 1 of the 5 highest-impact general medical journals ( The New Engl and Journal of Medicine , Lancet , Journal of the American Medical Association , Annals of Internal Medicine , and the British Medical Journal ) . We defined 2 levels of importance for qualitative signals : potentially invalidating changes in evidence , which would make one no longer want clinicians or policymakers to base decisions on the original findings ( such as a pivotal trial that characterized treatment effectiveness in terms opposite of those in the original systematic review ) , and major changes in evidence , which would affect clinical decision making in important ways without invalidating the previous results ( such as the identification of patient population s for whom treatment is more or less beneficial ) . Major changes also included differing characterizations of effectiveness that were less extreme than those for potentially invalidating signals but that would still affect clinical decision making ( for example , a change from possibly beneficial to definitely beneficial ) . Of importance , such characterizations as possibly effective , probably effective , and promising , were all categorized as possibly effective . Thus , qualitative signals for changes in evidence captured substantive differences in the characterization of treatment effects , not merely semantic differences . Full definitions for each of the specific signals can be found at www.ohri.ca/UpdatingSystRevs . Data Collection For each review , we characterized the clinical content area , eligibility criteria for included trials , definitions of reported outcomes , number of included trials and participants , meta-analytic result for each outcome , identification of statistical heterogeneity , and excerpted quotations of the authors ' characterizations of the main results . We also abstract ed whether a given outcome was explicitly identified as 1 of the primary or main outcomes . We discounted identification of more than 3 such outcomes as inconsistent with the We conducted a review of systematic review s ( SRs ) and r and omized-controlled trials ( RCTs ) to analyze efficacy and safety of cannabis-based medication in patients with mental disorders . Five data bases were systematic ally search ed ( 2006—August 2018 ) ; 4 SRs ( of 11 RCTs ) and 14 RCTs ( 1629 participants ) were included . Diagnoses were : dementia , cannabis and opioid dependence , psychoses/schizophrenia , general social anxiety , posttraumatic stress disorder , anorexia nervosa , attention-deficit hyperactivity disorder , and Tourette`s disorder . Outcome variables were too heterogeneous to conduct a meta- analysis . A narrative synthesis method was applied . The study quality was assessed using the risk-of-bias tool and SIGN-checklists . THC- and CBD-based medicines , given as adjunct to pharmaco- and psychotherapy , were associated with improvements of several symptoms of mental disorders , but not with remission . Side effects occurred , but severe adverse effects were mentioned in single cases only . In order to provide reliable treatment recommendations , more and larger RCTs with follow-up assessment s , consistent outcome measures and active comparisons are needed AIMS To analyse the effect on systematic review s in diabetes interventions of including only trials that are indexed in medline , and to assess the impact of adding trials from other data bases and the grey literature . METHODS All systematic review s of diabetes interventions which included a meta- analysis of r and omized controlled trials , and were published since 1996 , were selected . The impact on the meta- analysis of including only those trials indexed in medline , and the effect of then adding trials from other sources , was assessed . Where possible this was measured quantitatively , by redoing the meta- analysis , otherwise a qualitative estimate was made . RESULTS Forty-four systematic review s met our inclusion criteria . There were 120 articles reporting trial data which were not indexed in medline . These came from 52 % of the review s. In 34 % of the review s , basing a meta- analysis on a search of only medline would miss trials that could affect the result . Sources of non- medline data which had the biggest effect on the meta-analyses were journal articles from central and embase ( mainly in Diabetes , Nutrition and Metabolism ) and unpublished data ( mainly from industry ) . The exceptions were journal articles on herbal medicine , mostly indexed in Chinese language data bases . CONCLUSIONS A search of only the medline data base is insufficient for systematic review s of diabetes , because in about 34 % of review s the missed trials could affect the results of the meta- analysis . It is recommended that central ( on the Cochrane Library ) also be search ed . Scanning meeting abstract s , and seeking unpublished data are also recommended if the intervention has only recently been introduced In order to acquire an overview of the effectiveness of  antimicrobially impregnated catheters  on the prevention of  catheter related bloodstream infections ( CRI )  , we conducted a systematic review concentrating on r and omized controlled trials ( RCTs ) . The analysis end point was CRI ; therefore , studies focussing only on catheter colonization were excluded . We did not consider abstract s for analysis . We identified 24 RCTs investigating the effectiveness of  antimicrobially impregnated catheters .  In addition , we discovered five meta-analyses and four studies investigating cost effectiveness . For the majority of antimicrobially impregnated catheter types only a few studies were available , and not enough to draw conclusions . Therefore , despite a relatively large number of RCTs available , the routine use of antimicrobially impregnated catheters as a measure for CRI prevention remains controversial , with a need for more high quality studies Systematic review s , a cornerstone of evidence -based medicine , are not produced quickly enough to support clinical practice . The cost of production , availability of the requisite expertise and timeliness are often quoted as major contributors for the delay . This detailed survey of the state of the art of information systems design ed to support or automate individual tasks in the systematic review , and in particular systematic review s of r and omized controlled clinical trials , reveals trends that see the convergence of several parallel research projects . We surveyed literature describing informatics systems that support or automate the processes of systematic review or each of the tasks of the systematic review . Several projects focus on automating , simplifying and /or streamlining specific tasks of the systematic review . Some tasks are already fully automated while others are still largely manual . In this review , we describe each task and the effect that its automation would have on the entire systematic review process , summarize the existing information system support for each task , and highlight where further research is needed for realizing automation for the task . Integration of the systems that automate systematic review tasks may lead to a revised systematic review workflow . We envisage the optimized workflow will lead to system in which each systematic review is described as a computer program that automatically retrieves relevant trials , appraises them , extracts and synthesizes data , evaluates the risk of bias , performs meta- analysis calculations , and produces a report in real time Background Aprotinin is a serine protease inhibitor used to limit perioperative bleeding and reduce the need for donated blood transfusions during cardiac surgery . R and omized controlled trials of aprotinin evaluating its effect on the outcome of perioperative transfusion have been published since 1987 , and systematic review s were conducted in 1992 and 1997 . Methods A systematic search was conducted for all RCTs of aprotinin  that used placebo controls or were open-label with no active control treatment . Data collected included the primary outcome , objective of each study , whether a systematic review was cited or conducted as part of the background and /or rationale for the study and the number of previously published RCTs cited . Cumulative meta-analyses were performed . Results Sixty-four r and omized , controlled trials of aprotinin were found , conducted between 1987 and 2002 , reporting an endpoint of perioperative transfusion .  Median trial size was 64 subjects , with a range of 20 to 1784 . A cumulative meta- analysis indicated that aprotinin greatly decreased the need for perioperative transfusion , stabilizing at an odds ratio of 0.25 ( p , 10 2 6 ) by the 12th study , published in June of 1992 . The upper limit of the confidence interval never exceeded 0.65 and results were similar in all subgroups . Citation of previous RCTs was extremely low , with a median of 20 % of prior trials cited . Only 7 of 44 ( 15 % ) of subsequent reports referenced the largest trial ( N 1/4 1784 ) , which was 28 times larger than the median trial size . Conclusions This study demonstrates that investigators evaluating aprotinin were not adequately citing previous research , result ing in a large number of RCTs being conducted to address efficacy questions that prior trials had already definitively answered . Institutional review boards and journals could reduce the number of redundant trials by requiring investigators to conduct adequate search es for prior evidence and conducting systematic review OBJECTIVES To survey the frequency of use of indirect comparisons in systematic review s and evaluate the methods used in their analysis and interpretation . Also to identify alternative statistical approaches for the analysis of indirect comparisons , to assess the properties of different statistical methods used for performing indirect comparisons and to compare direct and indirect estimates of the same effects within review s. DATA SOURCES Electronic data bases . REVIEW METHODS The Data base of Abstract s of Review s of Effects ( DARE ) was search ed for systematic review s involving meta- analysis of r and omised controlled trials ( RCTs ) that reported both direct and indirect comparisons , or indirect comparisons alone . A systematic review of MEDLINE and other data bases was carried out to identify published methods for analysing indirect comparisons . Study design s were created using data from the International Stroke Trial . R and om sample s of patients receiving aspirin , heparin or placebo in 16 centres were used to create meta-analyses , with half of the trials comparing aspirin and placebo and half heparin and placebo . Methods for indirect comparisons were used to estimate the contrast between aspirin  and  heparin . The whole process was repeated 1000 times and the results were compared with direct comparisons and also theoretical results . Further detailed case studies comparing the results from both direct and indirect comparisons of the same effects were undertaken . RESULTS Of the review s identified through DARE , 31/327 ( 9.5 % ) included indirect comparisons . A further five review s including indirect comparisons were identified through electronic search ing . Few review s carried out a formal analysis and some based analysis on the naive addition of data from the treatment arms of interest . Few method ological papers were identified . Some valid approaches for aggregate data that could be applied using st and ard software were found : the adjusted indirect comparison , meta-regression and , for binary data only , multiple logistic regression ( fixed effect models only ) . Simulation studies showed that the naive method is liable to bias and also produces over-precise answers . Several methods provide correct answers if strong but unverifiable assumptions are fulfilled . Four times as many similarly sized trials are needed for the indirect approach to have the same power as directly r and omised comparisons . Detailed case studies comparing direct and indirect comparisons of the same effect show considerable statistical discrepancies , but the direction of such discrepancy is unpredictable . CONCLUSIONS Direct evidence from good- quality RCTs should be used wherever possible . Without this evidence , it may be necessary to look for indirect comparisons from RCTs . However , the results may be susceptible to bias . When making indirect comparisons within a systematic review , an adjusted indirect comparison method should ideally be used employing the r and om effects model . If both direct and indirect comparisons are possible within a review , it is recommended that these be done separately before considering whether to pool data . There is a need to evaluate methods for the analysis of indirect comparisons for continuous data and for empirical research into how different methods of indirect comparison perform in cases where there is a large treatment effect . Further study is needed into when it is appropriate to look at indirect comparisons and when to combine both direct and indirect comparisons . Research into how evidence from indirect comparisons compares to that from non-r and omised studies may also be warranted . Investigations using individual patient data from a meta- analysis of several RCTs using different protocol s and an evaluation of the impact of choosing different binary effect measures for the inverse variance method would also be useful Background The ideal evidence to answer a question about the effectiveness of treatment is a systematic review . However , for many clinical questions a systematic review will not be available , or may not be up to date . One option could be to use the evidence from an individual trial to answer the question ? Methods We assessed how often ( a ) the estimated effect and ( b ) the p-value in the most precise single trial in a meta- analysis agreed with the whole meta- analysis . For a r and om sample of 200 completed Cochrane Review s ( January , 2005 ) we identified a primary outcome and extracted : the number of trials , the statistical weight of the most precise trial , the estimate and confidence interval for both the highest weighted trial and the meta- analysis overall . We calculated the p-value for the most precise trial and meta- analysis . Results Of 200 review s , only 132 provided a meta- analysis of 2 or more trials , with a further 35 effect estimates based on single trials . The average number of trials was 7.3 , with the most precise trial contributing , on average , 51 % of the statistical weight to the summary estimate from the whole meta- analysis . The estimates of effect from the most precise trial and the overall meta-analyses were highly correlated ( rank correlation of 0.90).There was an 81 % agreement in statistical conclusions . Results from the most precise trial were statistically significant in 60 of the 167 evaluable review s , with 55 of the corresponding systematic review s also being statistically significant . The five discrepant results were not strikingly different with respect to their estimates of effect , but showed considerable statistical heterogeneity between trials in these meta-analyses . However , among the 101 cases in which the most precise trial was not statistically significant , the corresponding meta-analyses yielded 31 statistically significant results . Conclusions Single most precise trials provided similar estimates of effects to those of the meta-analyses to which they contributed , and statistically significant results are generally in agreement . However , " negative " results were less reliable , as may be expected from single underpowered trials . For systematic review ers we suggest that : ( 1 ) key trial(s ) in a review deserve greater attention ( 2 ) systematic review ers should check agreement of the most precise trial and the meta analysis . For clinicians using trials we suggest that when a meta- analysis is not available , a focus on the most precise trial is reasonable provided it is adequately powered In many areas of medicine the amount of published information is increasing at an exponential rate , making it difficult for the clinician to condense the data to a manageable amount of valuable and useful information . Systematic review s have been suggested as a remedy for this information overload . Such review s are regarded as the highest level of evidence . Certain statistical methods , e.g. , meta- analysis , have also been introduced for the calculation of a more comprehensive summation of the compiled results from studies with small sample sizes . These findings would then serve as an authoritarian guide for evidence -based practice . Endodontists have lately jumped on the b and wagon of systematic review s and meta-analyses , and papers on various topics are being published . Well done , such comprehensive information would be very useful and authoritative for the practitioner . Alarmingly , the quality of these recent publications is negatively correlated to the frequency . This can have serious consequences in the clinical arena if spurious information is given a seal of approval when communicated as facts in refereed journals . A systematic literature review is design ed to focus on a single question and to synthesize all high- quality research reports relevant to the question . In these studies , however , sources of bias are often not controlled . Therefore , even the best review and meta- analysis becomes useless if it is based on poorly design ed research . Furthermore , these review s are mostly based on published data which are too often biased toward studies that show significant differences in results and /or outcome . “ Uninteresting ” conclusions tend not to be published . Endodontic literature , thus far , is short on well design ed and executed r and omized clinical trials . Furthermore , clinical protocol s often have many important “ proprietary ” modifications that make comparison difficult . This makes it very hard to undertake a systematic review to answer a narrow question . Such GIGO ( garbage in , garbage out ) can easily lead to biased conclusions and reinforce already existing biased comclusions . An example of such bias can be illustrated by a meta- analysis recently published . The study focused on assessing if there were differences in outcome between 1 and 2 treatment visits when treating teeth with apical periodontitis . Relevant publications on this topic are rare , and with the narrow inclusion criteria only 3 investigations were available for the review . However , the only factors connecting these 3 studies was the words “ single ” and “ two visits ” in the title . Beyond that , the selected studies are too different and inadequate for the study . Only 1 study is somewhat demonstrably r and omized , and outcome assessment s are based on 3 vastly different criteria . Two of the studies use calcium hydroxide as intracanal dressing , whereas the third uses no intervisit medication . Complexity of initial pathology and healing time are also clearly factors of great importance but not controlled . In addition , sample sizes in the component studies as well as the final cohort are all too small for the conclusions that there was no significant difference between 1or 2-visit treatment protocol s. To undertake and publish a meta- analysis on such an incomplete sample is counterproductive . Although the publication noted its numerous limitations , it will still communicate erroneous conclusions with a poor scientific foundation to the less informed reader . There are other examples of recently published systematic review s that are very ambiguous and tend to communicate spurious facts . One of these studies looks at the effect of smear-layer removal on sealing ability of root canal obturation . The study is entirely limited to laboratory experiments , with the majority of evaluations using dye leakage which is generally considered to be unreliable . This is an example of review ers lacking content expertise . The authors draw the conclusion , using defective review material , that removal of smear layer enhances the seal of the root filling . We may generally believe that this is the truth Introduction The extraskeletal role of vitamin D is being increasingly recognised . This has important clinical implication s , as vitamin D deficiency has reached epidemic proportions worldwide . Vitamin D has proposed anti-inflammatory properties , yet the role of vitamin D supplementation in reducing inflammation remains largely unknown . The purpose of this review is to investigate the impact of vitamin D supplementation on inflammation , and to identify relevant knowledge gaps in the field . Methods and analysis Medline , CINAHL , EMBASE and All EBM will be systematic ally search ed for r and omised controlled trials ( RCTs ) and systematic review s of RCTs , comparing vitamin D supplementation with placebo , usual care or other pharmacological or non-pharmacological interventions . One review er will assess articles for eligibility according to prespecified selection criteria , after which 2 independent review ers will perform data extraction and quality appraisal . Meta-analyses will be conducted where appropriate . Ethics and dissemination Formal ethical approval is not required as no primary data is collected . This systematic review will identify potential clinical implication s of vitamin D deficiency and supplementation , and will be disseminated through a peer- review ed publication and at conference meetings , to inform future research on the efficacy of vitamin D supplementation for inflammation and inflammatory diseases . PROSPERO registration number CRD42016037104 OBJECTIVE The extent of disagreement between large and smaller r and omized , controlled trials on mental health issues is unknown . The authors aim ed to compare the results of large versus smaller trials on mental health-related interventions . METHOD The authors screened 161 Cochrane and 254 Data base of Abstract s of Review s of Effectiveness systematic review s on mental health-related interventions . They identified 16 meta-analyses with at least one " large " r and omized trial with sample size > 800 and at least one " smaller " trial .  Effect sizes were calculated separately for large and smaller trials . Heterogeneity was assessed between all studies , within each group ( large and smaller studies ) , and between large and smaller studies . RESULTS Significant between- study heterogeneity was seen in five meta-analyses . By r and om-effects calculations , the results of large and smaller trials differed beyond chance in four meta-analyses ( 25 % ) . In three of these disagreements ( effect of day care on IQ , discontinuation of antidepressants , risperidone versus typical antipsychotics for schizophrenia ) , the smaller trials showed greater effect sizes than the large trials . The inverse was seen in one case ( olanzapine versus typical antipsychotics for schizophrenia ) . With fixed-effects models , disagreements beyond chance occurred in five cases ( 31 % ) . In four meta-analyses , the effect size differed over twofold between large and smaller trials . Various quality and design parameters were identified as potential explanations for some disagreements . CONCLUSIONS Large trials are uncommon in mental health . Their results are usually comparable with the results of smaller studies , but major disagreements do occur . Both large and smaller trials should be scrutinized as they offer a continuum of r and omized evidence Introduction Vitamin D has potential benefits for extraskeletal health . These could include an anti-inflammatory effect as well as a reduction in endothelial dysfunction . We aim to provide quality evidence for the hypothesis that supplementation with vitamin D will improve endothelial function ( EF ) , possibly through the abrogation of systemic inflammation . Methods and analysis We will conduct a systematic review of all r and omised controlled trials on  vitamin D supplementation and EF lasting 12 weeks or more . The search will cover the period 2000–2015 and include studies that describe direct measures of EF  , markers of endothelial cell ( EC ) activation  and if concurrently reported , indicators of systemic inflammation  . Study selection will follow the Preferred Reporting Items for Systematic Review s and Meta-Analyses ( PRISMA ) guidelines and study quality will be assessed by the Jadad score in addition to an evaluation of allocation concealment and data analysis . If sufficient data are available , a meta- analysis will be conducted . The effect sizes will be generated using Hedges ’ g score , for both fixed and r and om effect models . I2 statistics and Galbraith plots will be used to assess heterogeneity and identify their potential sources . Potential publication and small sample size bias will be assessed by visual inspections of funnel plots and also Egger 's test . Meta-regression analysis ( if feasible ) will be conducted with restricted maximum likelihood ( REML ) estimation method , controlling for potential confounders ( demographics , study methods , location , etc ) . A backward elimination process will be applied in the regression modelling procedure . Subgroup analysis , conditional on number of studies retrieved and their sample size , will be stratified on participant disease category , total dose administered , degree of 25(OH)D change and type of supplement used . Ethics and dissemination Formal ethical approval is not required as primary data will not be collected . The results will be disseminated through a peer- review ed publication , conference presentation and the popular press . Trial registration number International Prospect i ve Register for Systematic Review s ( PROSPERO ) number CRD42014013523 Objective To summarize the evidence for curative and health enhancement effects through  forest therapy  and to assess the quality of studies based on a review of r and omized controlled trials ( RCTs ) . Study design A systematic review based on RCTs . Methods Studies were eligible if they were RCTs . Studies included one treatment group in which forest therapy was applied .  The following data bases – from 1990 to November 9 , 2010 – were search ed : MEDLINE via PubMed , CINAHL , Web of Science , and Ichushi- Web . All Cochrane data bases and Campbell Systematic Review s were also search ed up to November 9 , 2010 . Results Two trials met all inclusion criteria . No specific diseases were evaluated , and both studies reported significant effectiveness in one or more outcomes for health enhancement . However , the results of evaluations with the CONSORT ( Consoli date d St and ards of Reporting Trials ) 2010 and CLEAR NPT ( A Checklist to Evaluate a Report of a Nonpharmacological Trial ) checklists generally showed a remarkable lack of description in the studies . Furthermore , there was a problem of heterogeneity , thus a meta- analysis was unable to be performed . Conclusion Because there was insufficient evidence on forest therapy due to poor method ological and reporting quality and heterogeneity of RCTs , it was not possible to offer any conclusions about the effects of this intervention . However , it was possible to identify problems with current RCTs of forest therapy , and to propose a strategy for strengthening study quality and stressing the importance of study feasibility and original check items based on characteristics of forest therapy as a future research agenda
In the meta-regression analysis , changes in plasma cortisol concentrations following statin therapy were found to be independent of treatment duration .
Results of this meta- analysis of RCTs suggest a significant elevation in plasma cortisol levels following statin therapy
This study aim ed to perform a systematic review and meta- analysis of r and omized controlled trials ( RCTs ) in order to calculate the effect size of statin therapy in changing plasma cortisol concentrations .