bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estimating the effect of referral for nephrology care on the survival of adults with advanced chronic kidney disease in a real-world clinical setting
Authors: Liu Ping , Karim Mohammad Ehsanul , Ronksley Paul E , Hemmelgarn Brenda R , Quan Hude , Quinn Robert R , Ravani Pietro 
Published: September 2018

IntroductionLongitudinal studies ascertain exposure, covariates, and outcomes over time. For estimating treatment effect on mortality, ignoring the time-varying nature of an exposure may lead to immortal time bias. Time-dependent confounding that affects future treatment may bias the estimated effects. Differences in baseline prognosis between treatment groups further complicate this issue.
Objectives and ApproachWe applied sequential Cox modeling to estimate the causal effect of referral for nephrology care on the survival of adults with advanced chronic kidney disease, linking laboratory and administrative data from Alberta, Canada. We created pseudo-data by mimicking successive randomized controlled trials. To address immortal time bias, each “mini-trial” consisted of individuals starting treatment, and those not yet treated, in each 3-month time interval. We incorporated inverse-probability-of-treatment-weights (IPTW) to minimize treatment selection bias for each “mini-trial. ” We fit a “mini-trial”-stratified, weighted Cox model to estimate the overall hazard ratio for death by averaging the effect estimates across “mini-trials.”
ResultsWe included 9,675 patients who entered the cohort between 2002 and 2013. The mean age was 82 years; 35% were male; and 33% were ultimately referred to a nephrologist after a median wait-period of 6 months. Compared to non-referred patients, those referred were younger and had fewer comorbidities at baseline. Referral was associated with a significant 45% lower hazard for death in an adjusted Cox model. The effect was attenuated in a multivariate Cox model with a time-varying exposure and in a sequential Cox model further controlling for potential time-dependent confounding by measures reflecting kidney-, cardiovascular-, and cerebrovascular-health. After incorporating IPTW for addressing treatment selection bias in the same sequential Cox model, the effect estimate was toward the null and no longer significant.
Conclusion/ImplicationsWe found that applying analytical strategies that addressed immortal time bias, time-dependent confounding, and treatment selection bias, the survival benefit associated with nephrology referral was attenuated. Inverse-probability-of treatment weighted sequential Cox approach may be used to address these important biases and confounding that are common in real-world clinical settings.
Effectiveness of rotavirus vaccine against rotavirus-coded hospitalisations among Australian Aboriginal and non-Aboriginal children
Authors: Fathima Parveen , Snelling Tom 
Published: September 2018

IntroductionRotavirus vaccine, RV1 (Rotarix), was included in the immunisation programs in Western Australia (WA) and New South Wales from mid-2007. In WA, RV1 was replaced with RV5 (RotaTeq) in mid-2009. Marked declines in rotavirus-related hospitalisations in both Aboriginal and non-Aboriginal children have been demonstrated following the implementation of the program.
Objectives and ApproachWe aimed to assess RV1 vaccine effectiveness (VE) against rotavirus-coded hospitalisations among Aboriginal and non-Aboriginal children aged (1-hazard ratio*100) were obtained from Cox proportional hazards models (adjusted for infant, maternal and demographic factors and stratified by state of birth) for Aboriginal and non-Aboriginal children.
ResultsThere were a total of 623 rotavirus-coded hospitalisations among the cohort children aged <2 years. Rotavirus hospitalisation rates were 143.0/100,000 child-years (95% confidence interval [CI]: 113.3-180.4) among Aboriginal children and 49.0/100,000 child-years (95% CI: 44.8-53.5) among non-Aboriginal children.
Compared to unvaccinated children, 1-dose VE among Aboriginal children against rotavirus-coded hospitalisations was 52.1% (95% CI: -0.02-77.1%) and 2-dose VE was 62.4% (95% CI: 26.9-80.7%) adjusting for birthweight, region of residence, socio-economic status, and year of birth. Among non-Aboriginal children, 1-dose VE was 39.0% (95% CI: 13.1-57.2%) and 2-dose VE was 53.4% (95% CI: 38.1-65.1%) adjusting for birth weight, mode of delivery and maternal age at birth and year of birth.
Conclusion/ImplicationsBurden of rotavirus gastroenteritis remains significant in Aboriginal children. Given the previously demonstrated declines in rotavirus-related hospitalisations in this population following vaccine introduction, our lower-than-expected VE estimates might represent bias introduced by differences in health-seeking behaviour between the vaccinated and unvaccinated, herd immunity and/or possible non-differential misclassification of the outcome.
Health Inequalities in British Nurses using Census derived databases linked to an adjusted UK Index of Multiple Deprivation
Authors: Ball Will , Kyle Richard , Atherton Iain , Dougall Nadine 
Published: September 2018

IntroductionScottish health outcomes are worse than in England and Wales. This variation remains after controlling for deprivation, which explains less excess mortality now than previously. Alternative cross-national deprivation measures have limitations which may explain some of this trend. Recent policy interventions to reduce inequalities have not been effective.
Objectives and ApproachThis study aims to test a recently developed measure of area deprivation, the UK adjusted Index of Multiple Deprivation which has been linked to National Census derived Longitudinal Studies in England, Wales and Scotland. This adjusted measure is consistent across UK countries and addresses some limitations of previously utilised area measures of deprivation.
This study also aims to test whether characteristics of Nurses are protective against inequalities in health. This study will test whether Nurses are more socio-economically homogenous and whether higher health literacy is protective against the social gradient in health outcomes.
Results(1) Comparing Nurses to Non-Nurses in Scotland we found that they have systematically different demographic characteristics. Nurses are; older on average, more likely to be female, more likely to own their home, more likely to live in less deprived areas and they report better self-rated health. (1a) Correlation tests will examine the strength of relationship between health and Deprivation quintile for these groups.
(2) Comparing Self-Rated Health of Scottish Nurses with English and Welsh Nurses will determine whether any ‘excess’ in worse health outcomes exists and (2a) if an excess does exist, whether the UK consistent deprivation measure can account for this.
Analysis is currently ongoing and will be completed, with full results cleared for dissemination through disclosure control, prior to conference.
Conclusion/ImplicationsThis study implements methods which provide a basis for cross-national comparison of inequalities using individual-level data and a consistent measure of area deprivation.
Results from this study may also permit recommendations to improve the effectiveness of policy aimed at improving population health and reducing socio-economic inequalities in health.
Longitudinal trajectories of asthma exacerbations from infancy to school age.
Authors: Deliu Matea 
Published: September 2018

IntroductionPrevious studies which used data-driven methodologies have reported the existence of an exacerbation-prone asthma subtype, which is independent of asthma severity. However, longitudinal patterns of asthma exacerbations during childhood have not been studied.
Objectives and ApproachWe sought to investigate whether there are distinct longitudinal trajectories of asthma exacerbations from infancy to school-age that could facilitate better understanding of the heterogeneity of asthma syndrome.
We used longitudinal k-means modelling (an unsupervised data-driven method), to analyse linked primary care data from 916 participants in a population-based birth cohort study (Manchester Asthma and Allergy Study), to ascertain clusters of children with similar trajectories of asthma exacerbations during childhood (n=160). We tested the validity of these clusters in relation to lung function, airway hyperreactivity and inflammation, allergic sensitisation, and the use of asthma medication.
ResultsA two-cluster model provided the optimal solution for our data set. Based on the pattern of exacerbations from infancy to age 8 years, we assigned the clusters as: “Early-onset frequent exacerbations (FE)” (n=10) and “Infrequent exacerbations (IE)” (n=150). Shorter duration of breastfeeding was the strongest risk factor for FE (median weeks 0 (IQR: 0-1.75) vs IE, median weeks 6 (IQR: 0-20), p<0.001). Children in the FE cluster were more likely to exhibit persistent wheeze (90% vs 47%, p=0.03) and have poorer lung function, more airway hyperreactivity, and more airway inflammation throughout childhood (Table 1). In a post-hoc analysis, when we compared children in the exacerbation clusters with those who have wheezed only (n=389), and those that wheezed but had no exacerbations (n=338), other early life risk factors such as atopic sensitisation (IE - RR: 3.2 (95%CI: 2.1-5.1), p<0.001) (FE - RR: 10.9 (95%CI: 2.1-57.7), p=0.004), exposure to tobacco smoke at birth (FE - RR: 2.8 (95%CI: 1.3-6.3) ,p=0.02), position in sibship (IE - RR: 1.5 (95%CI: 1.0-2.3), p=0.03), and day care attendance (IE - RR:0.6 (95%CI: 0.4-0.9), p=0.01) were significantly associated with exacerbations.
Conclusion/ImplicationsWe have identified two distinct patterns of asthma exacerbations during childhood with different outcomes, early-life risk factors, and lung function when compared to children who wheeze, but have no exacerbations. These results indicate that exacerbations represent an independent susceptibility phenotype.
Statistical Population Register: using administrative in the Canadian Census
Authors: Cloutier Sylvain 
Published: September 2018

IntroductionFor a number of years, Statistics Canada has been evaluating the potential of increasing its use of administrative data into its Census Program. The research conducted so far has revealed that it could be possible to produce the census population counts by using existing administrative data.
Objectives and ApproachThe building of the Statistical Population Register (SPR) is one step towards achieving the use of administrative data into the Canadian Census Program. In addition, the SPR, in combination with the Business Register and the Statistical Building Register, would support a more efficient production of statistics via a multi-register-based system in the future. The SPR is created by linking numerous administrative data sources (federal, provincial, municipal and private). The in-scope Canadian population is then identified and extracted from the SPR.
ResultsThe presentation will focus on the reasons as well as the goals that had to be met in the initial research project in order to demonstrate the potential of using administrative data within the Census Program. The current state of the project will be highlighted by presenting high-level results at the Canadian, provincial and territorial levels. This is accomplished by comparing the Statistical Population Register’s in-scope population to its reference, Statistics Canada’s official population counts.
Conclusion/ImplicationsDespite promising results, areas of improvements have already been identified and work is under way in order to improve the quality of the upcoming Statistical Population Register. The final section of the presentation will be devoted to the future research agenda of the Census Program.
Using administrative health data to inform health service planning for specialist cancer care in Nova Scotia, Canada
Authors: Urquhart Robin , Lethbridge Lynn 
Published: September 2018

IntroductionResearch has demonstrated that primary care providers can safely and effectively provide follow-up care after a person has received treatment for cancer. Yet, discharge to primary care after cancer treatment is variable, despite the fact that cancer systems are challenged to provide follow-up care given constrained cancer specialist resources.
Objectives and ApproachTo inform cancer system planning, we examined (1) cancer centre routine follow-up (CC-FUP) care for prevalent cancer types and (2) changes in CC-FUP over time. From the Nova Scotia Cancer Registry, we identified all persons diagnosed in Nova Scotia, Canada, with an invasive breast, colorectal, gynecological, or prostate cancer between 01/01/2006 and 31/12/2013. We linked this dataset to cancer centre/clinic data and identified a non-metastatic cancer survivor cohort (n=12,267). Descriptive statistics were computed to describe patterns of care. Negative binomial regression was used to examine changes over time for both CC-FUP and all cancer centre visits, adjusting for other covariates.
ResultsNearly half of survivors (48.4\%) had at least one CC-FUP visit, which varied by disease site (range: 30.2-62.4\%). Variation existed across providers, with six oncologists providing 34.7\% of the CC-FUP visits to the study population. Year of diagnosis was associated with receipt of CC-FUP care, with each successive calendar year associated with an 8\% increase in CC-FUP visits (IRR=1.08, 95\%CI=1.07-1.10). Similarly, each successive calendar year was associated with a 14\% increase in all cancer centre visits (IRR=1.14, 95\%CI=1.13-1.15). Results were shared with cancer system decision-makers at regular intervals to inform ongoing analyses.
Conclusion/ImplicationsBoth the number of CC-FUP visits and all visits increased over time, with the latter at a greater rate. The increases were much higher than assumed by cancer system decision makers (2\% increase per year) for resource planning, demonstrating the value of population-based administrative data to informing health service planning.
Evaluating area-based socioeconomic status predictors of pediatric health outcomes in Manitoba
Authors: Kroeker Kristine , Sharma Atul , Chateau Dan , Brownell Marni , Rodd Celia 
Published: September 2018

IntroductionSocioeconomic gradients in health exist in Canada. Although multiple Canadian area-based socioeconomic measures (ABSM) have been developed, none have been specifically validated against relevant pediatric outcomes. Our objective was to use key pediatric health outcomes and compare the strength of association with a number of ABSM, including income quintile.
Objectives and ApproachThis is a retrospective cross-sectional assessment of the association between socioeconomic status (SES) measured by ABSM and key pediatric health outcomes at the population level. Data from the Manitoba Population Research Data Repository was used for residents aged 0-19y. The timeframe was 2010-2015. Outcomes included preterm births, birth weight, mortality, vaccination rates and teen pregnancy. Regressions used each outcome against various ABSM (e.g. CAN-Marg, SEFI2, INSPQ) or income quintile. Best model for each outcome was assessed by goodness of fit measure (AIC). Measures of inequality included SII (Slope Index of Inequality) and RII (Relative Index of Inequality, both RIImean and RIIratio).
ResultsIn our regression models, the 4 Can-Marg subcomponents consistently had about 15% lower AICs (best fit) across all 16 key pediatric outcomes compared to INSPQ (Raymond-Pampalon), income quintile or SEFI2 (Socioeconomic Factor Index - Version 2). Sex differences were small and inconsequential. Whether ABSMs were treated as continuous or categorical predictors was of little statistical consequence. Of note, 15 of the 16 outcomes had socioeconomic gradients identified by SII or RII on at least one of the ABSMs. Income quintile detected 12 of 15, CAN-Marg material deprivation detected 9; the combination of CAN-Marg material deprivation and ethnicity detected 13 of 15. SEFI2 detected only 3 and the National INSPQ detected 6.
Conclusion/ImplicationsThere are significant health inequalities in pediatric outcomes in Manitoba (15 of 16 studied). Combining CAN-Marg measures of poverty (material deprivation) and ethnic concentration identified 13/15 cases of documented inequality and was the best ABSM for capturing pediatric health gradients; it was similar to income quintile alone.
Patient Experiences with Cardiac Surgery in Alberta, Canada: Results from a Validated Survey
Authors: Kemp Kyle , Santana Maria , Knudtson Merril , Paolucci Elizabeth Oddone , Quan Hude 
Published: September 2018

IntroductionResearch shows that a better patient experience may be associated with better outcomes. Most investigations, however, have only examined patients’ overall rating of care, which does not identify individual aspects of care which may be improved. Additionally, little is known about the experience of specific clinical groups in acute care.
Objectives and ApproachThe study objective was to examine the experience of patients undergoing cardiac surgery across Alberta. Surveys were completed within 6 weeks of hospital discharge, and linked with inpatient administrative records. Study eligibility was determined using Canadian Classification of Intervention (CCI) procedure codes, to include patients who underwent coronary artery bypass graft (CABG), valve replacement, and/or percutaneous coronary intervention (angioplasty). The survey contained 56 questions and assessed multiple aspects of care. Results for each question were classified as percentage in “top box”, where “top box” represented the best possible result (e.g. nurses “always” explaining things in a way patients could understand).
ResultsFrom April 2014 to March 2017, 1,921 patients completed a survey following cardiac surgery. This included 1,117 angioplasty only (58.2%), 409 CABG only (21.3%), 308 valve replacements (16.0%) and 87 (4.5%) who underwent multiple procedures. Patients were predominantly male (74.2%), over 50 years of age (88.6%) and admitted to hospital urgently (72.7%). The top three performing questions were nurses treating patients with courtesy and respect (91.4% reporting “always”), receiving written information about symptoms to watch out for after leaving hospital (90.9% “yes”), and discussion with hospital staff about help needed once leaving hospital (90.2% “yes”). The three poorest performing questions were hospital room quietness at night (48.6% “always”), staff describing possible side effects of new medications (51.4% “always”), and hospital room/bathroom cleanliness (64.9% “always”).
Conclusion/ImplicationsOur results provide patient-reported feedback about the perceived strengths and areas for improvement associated with cardiac surgery in Alberta. By linking completed surveys with administrative data, we are able to examine the experience of specific clinical groups, while eliminating additional survey burden for patients.
No Strings Attached: The Impact of an Unconditional Prenatal Income Supplement on First Nations Birth and Early Childhood Outcomes
Authors: Brownell Marni , Chartier Mariette , Nickel Nathan , Campbell Rhonda , Enns Jennifer , Phillips-Beck Wanda , Chateau Dan , Burland Elaine , Sarkar Joykrishna , Lee Janelle Boram 
Published: September 2018

IntroductionIn Manitoba, low-income pregnant women are eligible for the Healthy Baby Prenatal Benefit (HBPB), an unconditional income supplement provided during the second and third trimester of pregnancy. HBPB is associated with improved birth outcomes for Manitoba women; its association with birth outcomes for First Nations (Indigenous) women is unknown.
Objectives and ApproachTo determine the association between HBPB and First Nations’ (FN) newborn and early childhood outcomes, we linked whole-population data from health, public health, family services and education. We included only FN women receiving income assistance during pregnancy (n=7074) to develop comparable treatment (received HBPB; n=5283) and comparison (no HBPB; n=1791) groups. Propensity score weighting adjusted for differences in maternal characteristics between groups. Multi-variable regressions compared groups on breastfeeding initiation, low birth weight, preterm birth, small- and large-for-gestational age, Apgar scores, complete immunizations at 1 and 2 years, and developmental vulnerability in kindergarten measured with the Early Development Instrument (EDI).
ResultsReceipt of the HBPB was associated with reductions in low birth weight births (adjusted Relative Risk (aRR): 0.77; 95% CI: 0.63, 0.93) and preterm births (aRR: 0.78 (0.68, 0.90)), and increases in breastfeeding initiation (aRR: 1.05 (1.00, 1.09)) and large-for-gestational age births (aRR: 1.11 (1.01, 1.23)). HBPB receipt during pregnancy was also associated with increases in 1- and 2-year immunizations for FN children (aRR: 1.14 (1.09, 1.19), and aRR: 1.28 (1.19, 1.36), respectively). Reductions in the risk of being developmentally vulnerable in the language and cognitive domain of the EDI were also found for FN children whose mothers had received the HBPB during pregnancy (aRR: 0.85 (0.74, 0.97).
Conclusion/ImplicationsA modest unconditional income supplement during pregnancy was associated with improved birth outcomes, increased immunization rates, and improved language and cognitive development at kindergarten for children born to low-income First Nations women. Long-term strategies to address structural inequities and the ongoing effects of colonization are also needed.
The Mysterious Case of the Delayed Twin: using research data to resolve linkage questions.
Authors: Avery Daniel 
Published: September 2018

IntroductionIn a large biobank of over half a million people, we have several pairs of participants who appear to share their genome. As more individuals are sequenced, more pairs are likely to be found. If these are twins then this is great news, but it isn’t quite that simple.
Objectives and ApproachWhere 2 people share a genome we need to be able to confirm that these pairs are twins. However, there are a number of issues which could cause 2 people to appear to share a genome; for example being recruited twice, donating blood on another’s behalf, etc. We already identify and exclude participant data based on these conditions. We developed our methodology by looking at the first identified pair in great detail, looking for evidence which specifically ruled out possible alternate explanations, and then applying and refining the method on later pairs.
ResultsWe were able to demonstrate the pair were almost certainly twins using their biochemistry and family questionnaire data as principal sources. We also identified a number of variables which were useful in indicating the likelihood of a twin, and now form part of a methodology which we are still developing. Even more usefully, we identified a number of variables that seemed like useful measures but proved extremely misleading. To date we have 26 pairs of possible twins, with 9 confirmed as twins and the remainder looking likely to be twins but falling short of a threshold for confidence. We also have 75 pairs which confirm duplicate participants we have already excluded.
Conclusion/ImplicationsWe formed two lessons: even very simply linkages come with pitfalls, and you should gather more administrative data than you think. We’re proposing the collection of additional familial relationship data in our third resurvey. We are also looking into machine learning and statistical techniques to better identify twins and duplicates.