the importance of early and intensive control of blood glucose levels in improving outcomes for people with type 2 diabetes mellitus ( t2 dm ) was established in the uk prospective diabetes study ( ukpds ) . despite differences in glucose levels between the intensive and standard treatment groups disappearing soon after completion of the active study intervention , the benefits of earlier intensive glycaemic control in reducing diabetic complications were found to persist in long - term ( 10-year ) follow - up . combined with evidence that even short periods ( i.e. weeks ) of hyperglycaemia increase the risk for developing diabetic complications , this highlights the importance of trying to establish good glycaemic control as early as possible . subsequent large - scale intervention studies have confirmed the benefit of intensive glycaemic control in reducing microvascular risk , but the findings regarding cardiovascular disease and overall mortality have been less conclusive . of note , what constitutes intensive therapy has evolved over the two decades since the ukpds as new antihyperglycaemic agents have become available . the newer agents , particularly those associated with a low risk of hypoglycaemia compared with sulphonylureas and insulin , offer new options for combination therapy aimed at achieving better glycaemic control . the global partnership for effective diabetes management was an early advocate for adoption of tailored targets and treatment in t2 dm , and subsequent guidelines have evolved to reflect the evidence , with universal glycaemic targets and treatment algorithms replaced with recommendations to individualize targets and treatment . while it seems clear that individualized targets are needed to optimize care , it is critical that good glycaemic control , as defined by individualized hba1c targets , is pursued without delay and with commitment . however , it is widely recognized that glucose levels are not well controlled in many people with t2 dm . through a review of recently published data , we aimed to summarize current standards of glycaemic control globally . we also sought to identify the factors that may contribute to poor rates of glycaemic control . searches were performed , last updated in july 2015 , in the us national library of medicine / national institutes of health pubmed database . abstracts of the publications identified by the searches were reviewed manually and included in the review if they reported ( 1 ) original data related to proportions of people with t2 dm achieving glycaemic control or ( 2 ) obstacles or barriers contributing to suboptimal glycaemic control . publications were excluded from the review if they were ( 1 ) published before 2011 or ( 2 ) published in a language other than english . manuscripts written originally in a language other than english but where an english translation is available were included . the search of the pubmed database was complemented by a manual search of online abstracts from recent ( 20132015 ) diabetes conferences including those from the european association for the study of diabetes and the american diabetes association annual meetings . terms used in the pubmed search were also entered into the google search engine , and the results were reviewed manually to identify any additional relevant data from credible sources that might inform the analysis and review . a meta - analysis was not performed owing to the diverse nature of the data collected . a total of 45 relevant publications were identified by the search strategy and included in the literature review and analysis . the results of the literature review suggest that suboptimal glycaemic control is a common and widespread problem . the proportion of patients not achieving hba1c targets in 12 studies published between 2011 and 2015 inclusive is summarized in table 1 . even in the study reporting the best rate of control , one in every three patients was above the hba1c target . a multi - centre , cross - sectional study of ~5800 people with t2 dm from nine european countries found that hba1c exceeded the target of 7.0% ( 53  mmol / mol ) in 37% of cases , with rates for individual countries ranging from 26% in the netherlands up to 52% in turkey . tidm : type 1 diabetes mellitus ; t2 dm : type 2 diabetes mellitus . target hba1c    7.0% ( 53  mmol / mol ) , other than for the study of laiteerapong et al . which used individualized targets of hba1c  < 6.5% , < 7.0% or < 8.0% ( < 48  mmol / mol , < 53  mmol / mol or < 64  mmol / mol ) based on patient characteristics . nine european countries : belgium , france , germany , greece , italy , the netherlands , spain , turkey and the united kingdom . other publications show that hba1c levels are markedly above target in a large proportion of people with t2 dm . in a registry - based study of > 10,000 people undergoing care for t2 dm in specialist clinics in canada , 62% were not at target [ hba1c    7.0% ( 53  mmol / mol ) ] and 15% had an hba1c level of 9.0% ( 75  mmol / mol ) or above . a puerto rican study of 600 adults with type 1 or type 2 diabetes reported that just 37% were at the recommended hba1c target . a survey of > 200,000 people with diabetes in taiwan found hba1c  >  9.0% ( 75  mmol / mol ) in nearly one in every four people and 30% of outpatients with t2 dm attending a medical college in rural india had hba1c    9.5% ( 80  mmol / mol ) . there was some evidence to suggest that suboptimal control occurred more frequently in low- and middle - income countries compared with wealthier countries , with the highest rate of 87% for non - achievement of hba1c target reported in rural india . however , high proportions of people in high - income , resource - rich settings also had inadequate control of hyperglycaemia . suboptimal glycaemic control is often accompanied by poor control of other cardiometabolic risk factors . in a prospective cohort study of more than 3000 people with t2 dm in canada , the proportion of people with hba1c , blood pressure and low - density lipoprotein ( ldl ) cholesterol at target on study entry was 47% , 46% and 36% , respectively . all three risk factors were controlled to target in just 19% of people , and only 7% maintained good control of glycaemia , blood pressure and ldl cholesterol throughout the 12-month study . a canadian study of more than 5000 people with t2 dm seen by 479 primary care physicians found that the proportions achieving targets were 50% for hba1c , 36% for blood pressure and 57% for ldl cholesterol , with only 13% reaching all three targets . similar results were found in more than 25,000 outpatients with t2 dm in china , with the proportions of patients achieving targets for hba1c , blood pressure and lipids of 48% , 28% and 36% , respectively . importantly , nearly all of the studies reviewed assessed the quality of glycaemic control against a single target of hba1c    7.0% ( 53  mmol / mol ) . within the context of individualized targets now recommended in guidelines , a somewhat higher target [ e.g. hba1c    7.5% ( 59  mmol / mol ) ] may have represented optimal management based on factors such as age , presence of cardiovascular comorbidities and duration of diabetes . this is unlikely to account for the large proportion of patients not controlled to hba1c    7.0% ( 53  mmol / mol ) and certainly should not justify the sizeable proportion of people with hba1c levels exceeding 9.0% ( 75  mmol / mol ) . however , it highlights that a single target is unlikely to represent optimal management for all people . the review provides strong evidence that in all regions of the world , many people with t2 dm are not achieving good glycaemic control . although there is considerable heterogeneity in the studies and the data generated , rates of uncontrolled glycaemia are typically in the range of 40%60% . consequently , many people are left at increased risk of diabetic complications and the associated burden of illness and mortality , as well as consequent economic costs . recent studies examining barriers to the achievement of good glycaemic control are summarized in table 2 . tidm : type 1 diabetes mellitus ; t2 dm : type 2 diabetes mellitus ; hcps : healthcare professionals . prescribers often identify poor patient motivation and self - management as leading barriers to achieving glycaemic targets . the second diabetes , attitudes , wishes and needs ( dawn2 ) study , included an online survey of 4785 healthcare professionals ( hcps ) ( ~40% primary care clinicians , 30% diabetes specialists , 20% nurses and 10% dieticians ) from 17 countries across four continents . the majority of the respondents ( 60% ) indicated a need for improvements in self - management by people with diabetes , particularly in the area of diet and exercise . resistance to lifestyle measures was also identified as a leading barrier by 252 primary care physicians , nurse practitioners and physician assistants in the united states , with 52% of hcps indicating that it was often or almost always a factor contributing to chronic lack of glycaemic control . other leading patient - related barriers identified by the hcps included psychosocial issues ( 34% ) , reluctance to use insulin ( 31% ) and non - compliance ( 30% ) . a study in the united kingdom examining the reasons for very poor glycaemic control [ hba1c    10% ( 86  mmol / mol ) ] in 128 people with t2 dm attending three primary care centres found poor adherence to lifestyle measures to be most frequently involved . other factors included infrequent clinic attendance ( 16% ) , side effects ( 16% ) , poor compliance with pharmacotherapy ( 14% ) , lack of knowledge of diabetes ( 14% ) , lack of titration of insulin ( 13% ) and insulin refusal ( 12% ) . poor patient motivation and adherence were also identified as barriers to good glycaemic control in qualitative studies with hcps . interviews with a small number ( n  =  9 ) of hcps in the united arab emirates revealed a tendency to view patient attitudes and behaviours as the origin of poor glycaemic control and to believe that if patients were more knowledgeable about diabetes , cooperated with hcps and were adherent with treatment , then they could achieve their glycaemic targets . the studies reviewed also revealed that a number of healthcare system - level factors are often seen as important barriers to good glycaemic control . the dawn2 study , for example , found that only 30% of the hcps surveyed believed that healthcare was well organized for the management of chronic conditions . participants from western european countries and china were more likely to feel that healthcare was well organized than those from north or south america , eastern europe , india or japan ( figure 1 ) . approximately half of the participants considered the healthcare remuneration system to be a barrier and most ( ~60% ) indicated a need for better access to qualified nurse educators / specialist diabetes nurses and psychologists / psychiatrists . proportion of healthcare professionals reporting that healthcare in their country is well organized for the management of chronic conditions , including debates . a survey of 47 european countries found that while all had guidelines in place for managing diabetes , only 7 ( 15% ) had protocols for monitoring their implementation . the majority ( 83% ) of countries had or were developing national plans for diabetes , but these were often not comprehensive . there was substantial variability in the provision of multidisciplinary care . while 80% reported that nurses play an important role in providing education for self - management , diabetes specialist nursing was recognized as a speciality in only 19 countries ( 40% ) . despite the widespread belief that patients need to be more engaged and effective in self - management , only 25% of the countries recommended continuous education for all people with diabetes . lack of effective self - management education was also identified as a barrier in a qualitative study involving focus group discussions with 25 primary care clinicians in the united states , along with a persistent focus on acute care , poor integration of diabetes care , lack of clinical information and inadequate public health support . lack of coordination in care and limited access to secondary resources were also identified as important barriers by studies in the netherlands and ireland . limitations on the time available to manage patients are often identified as an obstacle to good glycaemic control . in the survey of 252 us primary care physicians , lack of time for treating complex patients was reported as often or always a factor in failure to achieve good glycaemic control by 41% of the physicians . treatment costs were much less frequently seen as a barrier , with 25% of the hcps indicating that it made no contribution and most ( 58% ) saying that it was a factor in only a minority ( 20%40% ) of cases of poor glycaemic control . other studies have also suggested that hcps in primary care often feel that they lack the time or other resources needed to manage diabetes effectively . this raises particular concerns , given that health policy in some countries involves shifting more of the responsibility for diabetes management onto primary care . compared with patient- and system - related barriers to effective glycaemic control , there is limited information available regarding physician - related barriers . however , there is evidence to suggest that a lack of diabetes - focused education may be contributing to failure to achieve therapeutic targets . for example , one in five of the hcps surveyed in the dawn2 study indicated that they had received no formal postgraduate diabetes training , and in a uk survey , only 35% of 2149 trainee doctors felt that their postgraduate training had prepared them adequately to optimize treatment of diabetes and only 41% reported that they would take the initiative to optimize glycaemic control . a survey of 209 primary care clinicians in australia identified gaps in knowledge relating to the medical management of t2 dm , with 46% self - reporting a need for education on pharmacological management . it appears that prescribers often lack confidence in the use of insulin , particularly with more complex regimens . people with diabetes often continue in poor glycaemic control for extended periods of time without appropriate action being taken . a retrospective cohort study of > 80,000 people with t2 dm in the united kingdom revealed substantial delays in intensifying treatment when glycaemic control was suboptimal . for people who were inadequately controlled on one oral glucose lowering agent , the median time from hba1c being above a threshold of 7.0% ( 53  mmol / mol ) to treatment intensification with an additional oral agent was nearly 3  years , and even when hba1c was 8.0% ( 64  mmol / mol ) , intensification was delayed by a median of 1.6  years . there were even longer delays ( median of ~67  years ) in intensifying treatment with the addition of a third oral agent or the initiation of insulin . mean hba1c at intensification ranged from 8.7%9.7% ( 7283  mmol / mol ) . in a study of nearly 20,000 people with t2 dm initiated on basal insulin at hospitals across china , a study of primary care records of > 17,000 patients with t2 dm being treated with oral glucose  lowering agents in france found that > 3000 of the patients were not at glycaemic target and required treatment intensification . however , treatment was actually intensified in only 39% of the patients requiring it and the majority ( ~60% ) of changes were delayed by 6  months or more and a substantial proportion ( ~40% ) by more than a year . the diattitude study ( table 3 ) also looked at therapeutic inertia in the care of > 2000 people with t2 dm by 236 primary care physicians and found that among patients with uncontrolled glycaemia , representing 41% of all the patients studied , only 7% had their treatment intensified . the most common ( 60% ) reason given for not intensifying treatment was that the patient s hba1c was satisfactory . other leading reasons given included that lifestyle advice was more of a priority than changing medication ( 20% ) , the decision was postponed until the next clinic visit ( 11% ) and that hba1c had decreased since the previous clinic visit ( 7% ) , although in the majority ( 58% ) of these cases , an hba1c reduction was not confirmed by the available records . the problem appears to be common and widespread , with further studies in bahrain , croatia , spain , taiwan and the united states reporting high rates ( typically 30%60% ) of clinical inertia when managing elevated glucose levels in people with diabetes . summary of studies reporting rates of and factors contributing to therapeutic inertia in the management of type 2 diabetes . ldl : low - density lipoprotein ; t2 dm : type 2 diabetes mellitus ; hcps : healthcare professionals . a number of studies have attempted to explore the factors that may act as obstacles to action in addressing inadequate glycaemic control . in an online survey completed by 508 primary care physicians who provided data on 770 elderly patients ( > 65  years ) , the leading reason for not initiating glucose - lowering medication , given as the first - ranked reason for 58% of the patients and a contributory factor in nearly all patients , was that they were treated with diet and exercise , and presumably , this was believed to be adequate management ( figure 2 ) . however , 33% of the patients were not at target hba1c , suggesting substantial clinical inertia in this population . other reasons given for not starting drug treatment included that hyperglycaemia was mild ( 84% ) , patient concerns ( 61% ) , physician concerns about glucose - lowering agents ( 49% ) and presence of comorbidities and polypharmacy ( 37% ) . when asked to identify a threshold for initiating treatment with glucose - lowering agents in the elderly population , the mean hba1c threshold value stated was 7.1% ( 54  mmol / mol ) . in approximately 20% of the cases , the physicians indicated that they were planning to initiate glucose - lowering therapy within the next month , but more than half ( 54% ) of these patients already had an hba1c level above the physician - stated threshold . results from an online survey of 508 us primary care physicians providing clinical date for 770 patients . a qualitative study of 20 hcps in the united kingdom found a pattern of seeking to lessen their own sense of accountability for clinical inertia by emphasizing patient - level barriers such as comorbidities , motivation and self - management capabilities as well as health system  level barriers , especially time constraints . there was also a tendency for the hcps to overestimate the achievement of targets in their primary care centres . factors contributing to therapeutic inertia in the initiation of insulin treatment for t2 dm were investigated in the translating research into action for diabetes ( triad ) project using structured interviews with primary care hcps in the united states . the majority of the 83 clinicians interviewed supported guideline recommendations on glycaemic targets , with 69% choosing an hba1c  <  7% ( < 53  mmol / mol ) as the ideal target for good glycaemic control . at the same time , the most frequently cited reasons for setting higher individualized hba1c targets included advanced age or short life expectancy ( 54% ) , poor self - management capacity due to poor cognitive abilities ( 35% ) , presence of comorbidities ( 34% ) , low educational level or poor health literacy ( 34% ) and patients unwillingness to self - manage their diabetes ( 33% ) . the most frequent reasons cited by the clinicians for not initiating insulin treatment were patient refusal or resistance ( 64% ) and lack of patient self - management skills ( 43% ) . factors determining initiation of insulin were also investigated using data for 1933 people with t2 dm from the french national health and wellness survey , an annual internet - based survey among french adults . early initiation of insulin therapy was almost 10 times more likely to be prescribed by an endocrinologist or diabetologist than by a primary care physician . early versus late insulin initiation was also more likely in patients who were younger , had diabetes - related complications or smoked . insulin - treated patients were more likely to be adherent , and there was no apparent deterioration in quality of life associated with insulin use . in focus group discussions with 114 primary care physicians in belgium , many of the physicians found the concept of clinical inertia interesting , but some also found it insulting and felt it implied that they were passive in their work . they also noted that it was important to differentiate between cases where there was a conscious decision to not pursue lower targets based on a consideration of the individual patient factors and those where there was genuine inertia . it was acknowledged that genuine clinical inertia was a real risk in primary care , but there was a tendency to ascribe this risk to patient- and system - level barriers rather than physician - level behaviours and practices . in summary , recent studies suggest that clinical inertia is a common and widespread problem , typically affecting the care of 30%50% of people with t2 dm . the causes are diverse and complex , but surveys of hcps tend to emphasize patient - level barriers to treatment intensification , such as patient reluctance to start insulin therapy , or system - level barriers , such as disconnects between what is recommended in guidelines and what is reimbursed in practice . however , it also appears that hcps sometimes delay taking necessary action and may be willing to tolerate periods of it also appears that many hcps , while recognizing the importance of good glycaemic control , have low expectations for their patients . the issue of clinical inertia needs to be better understood if it is to be addressed effectively , particularly regarding the patient- , hcp- and system - level factors that underlie it . this is challenging as clinical inertia as defined in studies typically captures a range of behaviours , some of which may not reflect suboptimal care . however , studies of clinical inertia often apply a single glycaemic threshold [ typically hba1c  =  7% ( 53  mmol / mol ) ] across a broad range of patients . guidelines for management of t2 dm have traditionally advocated a stepwise approach to management , in which treatment is started with diet and exercise , followed by the addition of oral antihyperglycaemic monotherapy , then combination therapy and eventually insulin . however , when applied systematically without considering individual factors such as the patient s current hba1c level , it can lead to treatment futility with people receiving therapy that has little chance of lowering glucose levels sufficiently to achieve their glycaemic target . several recent publications have indicated potential benefits of early , intensive intervention with pharmacotherapy , including combinations of oral glucose  lowering agents and/or insulin . the treatment options for type 2 diabetes in adolescents and youth ( today ) study compared metformin alone , metformin plus a thiazolidinedione and metformin plus intensive lifestyle intervention as initial therapy for new - onset t2 dm in people aged 1017  years and with obesity . the proportion of people who maintained glycaemic control over 5  years was significantly higher with the combination pharmacotherapy than either metformin alone or metformin plus intensive lifestyle measures . the combination pharmacotherapy was also associated with greater improvements in insulin sensitivity and -cell function compared with the other two approaches . the results lend support to early , intensive intervention with combination therapy , at least in this population of young people with new - onset t2 dm . early intensive therapy was also studied in older ( mean age  =  45  years ) people with newly diagnosed t2 dm who started treatment for 3  months with metformin plus insulin and were then randomized to either continuing metformin plus insulin therapy or triple oral glucose  lowering therapy with metformin , glyburide and pioglitazone . good glycaemic control was maintained for over 6  years with no significant difference between the groups ( end of study hba1c  =  7.3% for metformin plus insulin and 6.4 for triple oral combination ; p  =  0.4 ) . a review of the health records for nearly 3000 people with t2 dm in the united states found that early initiation of metformin ( within 6  months of diagnosis ) significantly reduced hba1c ( 0.36% ; p  <  0.001 ) and bmi ( 0.46  kg / m ; p  < the likelihood of achieving hba1c    7% was doubled and the likelihood of requiring therapy intensification was reduced by 28% with early versus delayed initiation of metformin . another study in the united states looking at medical records for 5870 people with t2 dm found a similar pattern for early introduction of combination oral glucose early intensification was defined as addition of a second oral drug to metformin therapy within 3  months of treatment failure ( hba1c    7.5% ) and late intensification as the introduction of combination therapy 1015  months after loss of glycaemic control . people who received early intensification were 38% more likely to achieve good glycaemic control at 1.52  years than those with late intensification . in the advance trial of 11,140 patients with t2 dm , therapeutic intensification with addition of an oral glucose lowering agent doubled the chance of achieving good glycaemic control , and with intensification with insulin , the odds were increased 2.5-fold . a total of 45 relevant publications were identified by the search strategy and included in the literature review and analysis . the results of the literature review suggest that suboptimal glycaemic control is a common and widespread problem . the proportion of patients not achieving hba1c targets in 12 studies published between 2011 and 2015 inclusive is summarized in table 1 . even in the study reporting the best rate of control , one in every three patients was above the hba1c target . a multi - centre , cross - sectional study of ~5800 people with t2 dm from nine european countries found that hba1c exceeded the target of 7.0% ( 53  mmol / mol ) in 37% of cases , with rates for individual countries ranging from 26% in the netherlands up to 52% in turkey . target hba1c    7.0% ( 53  mmol / mol ) , other than for the study of laiteerapong et al . which used individualized targets of hba1c  <  6.5% , < 7.0% or < 8.0% ( < 48  mmol / mol , < 53  mmol / mol or < 64  mmol / mol ) based on patient characteristics . nine european countries : belgium , france , germany , greece , italy , the netherlands , spain , turkey and the united kingdom . other publications show that hba1c levels are markedly above target in a large proportion of people with t2 dm . in a registry - based study of > 10,000 people undergoing care for t2 dm in specialist clinics in canada , 62% were not at target [ hba1c    7.0% ( 53  mmol / mol ) ] and 15% had an hba1c level of 9.0% ( 75  mmol / mol ) or above . a puerto rican study of 600 adults with type 1 or type 2 diabetes reported that just 37% were at the recommended hba1c target . a survey of > 200,000 people with diabetes in taiwan found hba1c  >  9.0% ( 75  mmol / mol ) in nearly one in every four people and 30% of outpatients with t2 dm attending a medical college in rural india had hba1c    9.5% ( 80  mmol / mol ) . there was some evidence to suggest that suboptimal control occurred more frequently in low- and middle - income countries compared with wealthier countries , with the highest rate of 87% for non - achievement of hba1c target reported in rural india . however , high proportions of people in high - income , resource - rich settings also had inadequate control of hyperglycaemia . suboptimal glycaemic control is often accompanied by poor control of other cardiometabolic risk factors . in a prospective cohort study of more than 3000 people with t2 dm in canada , the proportion of people with hba1c , blood pressure and low - density lipoprotein ( ldl ) cholesterol at target on study entry was 47% , 46% and 36% , respectively . all three risk factors were controlled to target in just 19% of people , and only 7% maintained good control of glycaemia , blood pressure and ldl cholesterol throughout the 12-month study . a canadian study of more than 5000 people with t2 dm seen by 479 primary care physicians found that the proportions achieving targets were 50% for hba1c , 36% for blood pressure and 57% for ldl cholesterol , with only 13% reaching all three targets . similar results were found in more than 25,000 outpatients with t2 dm in china , with the proportions of patients achieving targets for hba1c , blood pressure and lipids of 48% , 28% and 36% , respectively . importantly , nearly all of the studies reviewed assessed the quality of glycaemic control against a single target of hba1c    7.0% ( 53  mmol / mol ) . within the context of individualized targets now recommended in guidelines , a somewhat higher target [ e.g. hba1c    7.5% ( 59  mmol / mol ) ] may have represented optimal management based on factors such as age , presence of cardiovascular comorbidities and duration of diabetes . this is unlikely to account for the large proportion of patients not controlled to hba1c    7.0% ( 53  mmol / mol ) and certainly should not justify the sizeable proportion of people with hba1c levels exceeding 9.0% ( 75  mmol / mol ) . however , it highlights that a single target is unlikely to represent optimal management for all people . the review provides strong evidence that in all regions of the world , many people with t2 dm are not achieving good glycaemic control . although there is considerable heterogeneity in the studies and the data generated , rates of uncontrolled glycaemia are typically in the range of 40%60% . consequently , many people are left at increased risk of diabetic complications and the associated burden of illness and mortality , as well as consequent economic costs . recent studies examining barriers to the achievement of good glycaemic control are summarized in table 2 . tidm : type 1 diabetes mellitus ; t2 dm : type 2 diabetes mellitus ; hcps : healthcare professionals . prescribers often identify poor patient motivation and self - management as leading barriers to achieving glycaemic targets . the second diabetes , attitudes , wishes and needs ( dawn2 ) study , included an online survey of 4785 healthcare professionals ( hcps ) ( ~40% primary care clinicians , 30% diabetes specialists , 20% nurses and 10% dieticians ) from 17 countries across four continents . the majority of the respondents ( 60% ) indicated a need for improvements in self - management by people with diabetes , particularly in the area of diet and exercise . resistance to lifestyle measures was also identified as a leading barrier by 252 primary care physicians , nurse practitioners and physician assistants in the united states , with 52% of hcps indicating that it was often or almost always a factor contributing to chronic lack of glycaemic control . other leading patient - related barriers identified by the hcps included psychosocial issues ( 34% ) , reluctance to use insulin ( 31% ) and non - compliance ( 30% ) . a study in the united kingdom examining the reasons for very poor glycaemic control [ hba1c    10% ( 86  mmol / mol ) ] in 128 people with t2 dm attending three primary care centres found poor adherence to lifestyle measures to be most frequently involved . other factors included infrequent clinic attendance ( 16% ) , side effects ( 16% ) , poor compliance with pharmacotherapy ( 14% ) , lack of knowledge of diabetes ( 14% ) , lack of titration of insulin ( 13% ) and insulin refusal ( 12% ) . poor patient motivation and adherence were also identified as barriers to good glycaemic control in qualitative studies with hcps . interviews with a small number ( n  =  9 ) of hcps in the united arab emirates revealed a tendency to view patient attitudes and behaviours as the origin of poor glycaemic control and to believe that if patients were more knowledgeable about diabetes , cooperated with hcps and were adherent with treatment , then they could achieve their glycaemic targets . the studies reviewed also revealed that a number of healthcare system - level factors are often seen as important barriers to good glycaemic control . the dawn2 study , for example , found that only 30% of the hcps surveyed believed that healthcare was well organized for the management of chronic conditions . participants from western european countries and china were more likely to feel that healthcare was well organized than those from north or south america , eastern europe , india or japan ( figure 1 ) . approximately half of the participants considered the healthcare remuneration system to be a barrier and most ( ~60% ) indicated a need for better access to qualified nurse educators / specialist diabetes nurses and psychologists / psychiatrists . proportion of healthcare professionals reporting that healthcare in their country is well organized for the management of chronic conditions , including debates . a survey of 47 european countries found that while all had guidelines in place for managing diabetes , only 7 ( 15% ) had protocols for monitoring their implementation . the majority ( 83% ) of countries had or were developing national plans for diabetes , but these were often not comprehensive there was substantial variability in the provision of multidisciplinary care . while 80% reported that nurses play an important role in providing education for self - management , diabetes specialist nursing was recognized as a speciality in only 19 countries ( 40% ) . despite the widespread belief that patients need to be more engaged and effective in self - management , only 25% of the countries recommended continuous education for all people with diabetes . lack of effective self - management education was also identified as a barrier in a qualitative study involving focus group discussions with 25 primary care clinicians in the united states , along with a persistent focus on acute care , poor integration of diabetes care , lack of clinical information and inadequate public health support . lack of coordination in care and limited access to secondary resources were also identified as important barriers by studies in the netherlands and ireland . limitations on the time available to manage patients are often identified as an obstacle to good glycaemic control . in the survey of 252 us primary care physicians , lack of time for treating complex patients was reported as often or always a factor in failure to achieve good glycaemic control by 41% of the physicians . treatment costs were much less frequently seen as a barrier , with 25% of the hcps indicating that it made no contribution and most ( 58% ) saying that it was a factor in only a minority ( 20%40% ) of cases of poor glycaemic control . other studies have also suggested that hcps in primary care often feel that they lack the time or other resources needed to manage diabetes effectively . this raises particular concerns , given that health policy in some countries involves shifting more of the responsibility for diabetes management onto primary care . compared with patient- and system - related barriers to effective glycaemic control , there is limited information available regarding physician - related barriers . however , there is evidence to suggest that a lack of diabetes - focused education may be contributing to failure to achieve therapeutic targets . for example , one in five of the hcps surveyed in the dawn2 study indicated that they had received no formal postgraduate diabetes training , and in a uk survey , only 35% of 2149 trainee doctors felt that their postgraduate training had prepared them adequately to optimize treatment of diabetes and only 41% reported that they would take the initiative to optimize glycaemic control . a survey of 209 primary care clinicians in australia identified gaps in knowledge relating to the medical management of t2 dm , with 46% self - reporting a need for education on pharmacological management . it appears that prescribers often lack confidence in the use of insulin , particularly with more complex regimens . prescribers often identify poor patient motivation and self - management as leading barriers to achieving glycaemic targets . the second diabetes , attitudes , wishes and needs ( dawn2 ) study , included an online survey of 4785 healthcare professionals ( hcps ) ( ~40% primary care clinicians , 30% diabetes specialists , 20% nurses and 10% dieticians ) from 17 countries across four continents . the majority of the respondents ( 60% ) indicated a need for improvements in self - management by people with diabetes , particularly in the area of diet and exercise . resistance to lifestyle measures was also identified as a leading barrier by 252 primary care physicians , nurse practitioners and physician assistants in the united states , with 52% of hcps indicating that it was often or almost always a factor contributing to chronic lack of glycaemic control . other leading patient - related barriers identified by the hcps included psychosocial issues ( 34% ) , reluctance to use insulin ( 31% ) and non - compliance ( 30% ) . a study in the united kingdom examining the reasons for very poor glycaemic control [ hba1c    10% ( 86  mmol / mol ) ] in 128 people with t2 dm attending three primary care centres found poor adherence to lifestyle measures to be most frequently involved . other factors included infrequent clinic attendance ( 16% ) , side effects ( 16% ) , poor compliance with pharmacotherapy ( 14% ) , lack of knowledge of diabetes ( 14% ) , lack of titration of insulin ( 13% ) and insulin refusal ( 12% ) . poor patient motivation and adherence were also identified as barriers to good glycaemic control in qualitative studies with hcps . interviews with a small number ( n  =  9 ) of hcps in the united arab emirates revealed a tendency to view patient attitudes and behaviours as the origin of poor glycaemic control and to believe that if patients were more knowledgeable about diabetes , cooperated with hcps and were adherent with treatment , then they could achieve their glycaemic targets . the studies reviewed also revealed that a number of healthcare system - level factors are often seen as important barriers to good glycaemic control . the dawn2 study , for example , found that only 30% of the hcps surveyed believed that healthcare was well organized for the management of chronic conditions . participants from western european countries and china were more likely to feel that healthcare was well organized than those from north or south america , eastern europe , india or japan ( figure 1 ) . approximately half of the participants considered the healthcare remuneration system to be a barrier and most ( ~60% ) indicated a need for better access to qualified nurse educators / specialist diabetes nurses and psychologists / psychiatrists . proportion of healthcare professionals reporting that healthcare in their country is well organized for the management of chronic conditions , including debates . a survey of 47 european countries found that while all had guidelines in place for managing diabetes , only 7 ( 15% ) had protocols for monitoring their implementation . the majority ( 83% ) of countries had or were developing national plans for diabetes , but these were often not comprehensive . there was substantial variability in the provision of multidisciplinary care . while 80% reported that nurses play an important role in providing education for self - management , diabetes specialist nursing was recognized as a speciality in only 19 countries ( 40% ) . despite the widespread belief that patients need to be more engaged and effective in self - management , only 25% of the countries recommended continuous education for all people with diabetes . lack of effective self - management education was also identified as a barrier in a qualitative study involving focus group discussions with 25 primary care clinicians in the united states , along with a persistent focus on acute care , poor integration of diabetes care , lack of clinical information and inadequate public health support . lack of coordination in care and limited access to secondary resources were also identified as important barriers by studies in the netherlands and ireland . limitations on the time available to manage patients are often identified as an obstacle to good glycaemic control . in the survey of 252 us primary care physicians , lack of time for treating complex patients was reported as often or always a factor in failure to achieve good glycaemic control by 41% of the physicians . treatment costs were much less frequently seen as a barrier , with 25% of the hcps indicating that it made no contribution and most ( 58% ) saying that it was a factor in only a minority ( 20%40% ) of cases of poor glycaemic control . other studies have also suggested that hcps in primary care often feel that they lack the time or other resources needed to manage diabetes effectively . this raises particular concerns , given that health policy in some countries involves shifting more of the responsibility for diabetes management onto primary care . compared with patient- and system - related barriers to effective glycaemic control , there is limited information available regarding physician - related barriers . however , there is evidence to suggest that a lack of diabetes - focused education may be contributing to failure to achieve therapeutic targets . for example , one in five of the hcps surveyed in the dawn2 study indicated that they had received no formal postgraduate diabetes training , and in a uk survey , only 35% of 2149 trainee doctors felt that their postgraduate training had prepared them adequately to optimize treatment of diabetes and only 41% reported that they would take the initiative to optimize glycaemic control . a survey of 209 primary care clinicians in australia identified gaps in knowledge relating to the medical management of t2 dm , with 46% self - reporting a need for education on pharmacological management . it appears that prescribers often lack confidence in the use of insulin , particularly with more complex regimens . people with diabetes often continue in poor glycaemic control for extended periods of time without appropriate action being taken . a retrospective cohort study of > 80,000 people with t2 dm in the united kingdom revealed substantial delays in intensifying treatment when glycaemic control was suboptimal . for people who were inadequately controlled on one oral glucose lowering agent , the median time from hba1c being above a threshold of 7.0% ( 53  mmol / mol ) to treatment intensification with an additional oral agent was nearly 3  years , and even when hba1c was 8.0% ( 64  mmol / mol ) , intensification was delayed by a median of 1.6  years . there were even longer delays ( median of ~67  years ) in intensifying treatment with the addition of a third oral agent or the initiation of insulin . mean hba1c at intensification ranged from 8.7%9.7% ( 7283  mmol / mol ) . in a study of nearly 20,000 people with t2 dm initiated on basal insulin at hospitals across china , mean hba1c at the time of insulin initiation was 9.6% . a study of primary care records of > 17,000 patients with t2 dm being treated with oral glucose  lowering agents in france found that > 3000 of the patients were not at glycaemic target and required treatment intensification . however , treatment was actually intensified in only 39% of the patients requiring it and the majority ( ~60% ) of changes were delayed by 6  months or more and a substantial proportion ( ~40% ) by more than a year . the diattitude study ( table 3 ) also looked at therapeutic inertia in the care of > 2000 people with t2 dm by 236 primary care physicians and found that among patients with uncontrolled glycaemia , representing 41% of all the patients studied , only 7% had their treatment intensified . the most common ( 60% ) reason given for not intensifying treatment was that the patient s hba1c was satisfactory . other leading reasons given included that lifestyle advice was more of a priority than changing medication ( 20% ) , the decision was postponed until the next clinic visit ( 11% ) and that hba1c had decreased since the previous clinic visit ( 7% ) , although in the majority ( 58% ) of these cases , an hba1c reduction was not confirmed by the available records . the problem appears to be common and widespread , with further studies in bahrain , croatia , spain , taiwan and the united states reporting high rates ( typically 30%60% ) of clinical inertia when managing elevated glucose levels in people with diabetes . summary of studies reporting rates of and factors contributing to therapeutic inertia in the management of type 2 diabetes . ldl : low - density lipoprotein ; t2 dm : type 2 diabetes mellitus ; hcps : healthcare professionals . a number of studies have attempted to explore the factors that may act as obstacles to action in addressing inadequate glycaemic control . in an online survey completed by 508 primary care physicians who provided data on 770 elderly patients ( > 65  years ) , the leading reason for not initiating glucose - lowering medication , given as the first - ranked reason for 58% of the patients and a contributory factor in nearly all patients , was that they were treated with diet and exercise , and presumably , this was believed to be adequate management ( figure 2 ) . however , 33% of the patients were not at target hba1c , suggesting substantial clinical inertia in this population . other reasons given for not starting drug treatment included that hyperglycaemia was mild ( 84% ) , patient concerns ( 61% ) , physician concerns about glucose - lowering agents ( 49% ) and presence of comorbidities and polypharmacy ( 37% ) . when asked to identify a threshold for initiating treatment with glucose - lowering agents in the elderly population , the mean hba1c threshold value stated was 7.1% ( 54  mmol / mol ) . in approximately 20% of the cases , the physicians indicated that they were planning to initiate glucose - lowering therapy within the next month , but more than half ( 54% ) of these patients already had an hba1c level above the physician - stated threshold . results from an online survey of 508 us primary care physicians providing clinical date for 770 patients . a qualitative study of 20 hcps in the united kingdom found a pattern of seeking to lessen their own sense of accountability for clinical inertia by emphasizing patient - level barriers such as comorbidities , motivation and self - management capabilities as well as health system  level barriers , especially time constraints . there was also a tendency for the hcps to overestimate the achievement of targets in their primary care centres . factors contributing to therapeutic inertia in the initiation of insulin treatment for t2 dm were investigated in the translating research into action for diabetes ( triad ) project using structured interviews with primary care hcps in the united states . the majority of the 83 clinicians interviewed supported guideline recommendations on glycaemic targets , with 69% choosing an hba1c  <  7% ( < 53  mmol / mol ) as the ideal target for good glycaemic control . at the same time , the most frequently cited reasons for setting higher individualized hba1c targets included advanced age or short life expectancy ( 54% ) , poor self - management capacity due to poor cognitive abilities ( 35% ) , presence of comorbidities ( 34% ) , low educational level or poor health literacy ( 34% ) and patients unwillingness to self - manage their diabetes ( 33% ) . the most frequent reasons cited by the clinicians for not initiating insulin treatment were patient refusal or resistance ( 64% ) and lack of patient self - management skills ( 43% ) . factors determining initiation of insulin were also investigated using data for 1933 people with t2 dm from the french national health and wellness survey , an annual internet - based survey among french adults . early initiation of insulin therapy was almost 10 times more likely to be prescribed by an endocrinologist or diabetologist than by a primary care physician . early versus late insulin initiation was also more likely in patients who were younger , had diabetes - related complications or smoked . insulin - treated patients were more likely to be adherent , and there was no apparent deterioration in quality of life associated with insulin use . in focus group discussions with 114 primary care physicians in belgium , many of the physicians found the concept of clinical inertia interesting , but some also found it insulting and felt it implied that they were passive in their work . they also noted that it was important to differentiate between cases where there was a conscious decision to not pursue lower targets based on a consideration of the individual patient factors and those where there was genuine inertia . it was acknowledged that genuine clinical inertia was a real risk in primary care , but there was a tendency to ascribe this risk to patient- and system - level barriers rather than physician - level behaviours and practices . in summary , recent studies suggest that clinical inertia is a common and widespread problem , typically affecting the care of 30%50% of people with t2 dm . the causes are diverse and complex , but surveys of hcps tend to emphasize patient - level barriers to treatment intensification , such as patient reluctance to start insulin therapy , or system - level barriers , such as disconnects between what is recommended in guidelines and what is reimbursed in practice . however , it also appears that hcps sometimes delay taking necessary action and may be willing to tolerate periods of it also appears that many hcps , while recognizing the importance of good glycaemic control , have low expectations for their patients . the issue of clinical inertia needs to be better understood if it is to be addressed effectively , particularly regarding the patient- , hcp- and system - level factors that underlie it . this is challenging as clinical inertia as defined in studies typically captures a range of behaviours , some of which may not reflect suboptimal care . however , studies of clinical inertia often apply a single glycaemic threshold [ typically hba1c  =  7% ( 53  mmol / mol ) ] across a broad range of patients . guidelines for management of t2 dm have traditionally advocated a stepwise approach to management , in which treatment is started with diet and exercise , followed by the addition of oral antihyperglycaemic monotherapy , then combination therapy and eventually insulin . however , when applied systematically without considering individual factors such as the patient s current hba1c level , it can lead to treatment futility with people receiving therapy that has little chance of lowering glucose levels sufficiently to achieve their glycaemic target . several recent publications have indicated potential benefits of early , intensive intervention with pharmacotherapy , including combinations of oral glucose  lowering agents and/or insulin . the treatment options for type 2 diabetes in adolescents and youth ( today ) study compared metformin alone , metformin plus a thiazolidinedione and metformin plus intensive lifestyle intervention as initial therapy for new - onset t2 dm in people aged 1017  years and with obesity . the proportion of people who maintained glycaemic control over 5  years was significantly higher with the combination pharmacotherapy than either metformin alone or metformin plus intensive lifestyle measures . the combination pharmacotherapy was also associated with greater improvements in insulin sensitivity and -cell function compared with the other two approaches . the results lend support to early , intensive intervention with combination therapy , at least in this population of young people with new - onset t2 dm . early intensive therapy was also studied in older ( mean age  =  45  years ) people with newly diagnosed t2 dm who started treatment for 3  months with metformin plus insulin and were then randomized to either continuing metformin plus insulin therapy or triple oral glucose good glycaemic control was maintained for over 6  years with no significant difference between the groups ( end of study hba1c  =  7.3% for metformin plus insulin and 6.4 for triple oral combination ; p  =  0.4 ) . a review of the health records for nearly 3000 people with t2 dm in the united states found that early initiation of metformin ( within 6  months of diagnosis ) significantly reduced hba1c ( 0.36% ; p  <  0.001 ) and bmi ( 0.46  kg / m ; p  <  0.001 ) compared with when introduction of pharmacotherapy with metformin was delayed . the likelihood of achieving hba1c    7% was doubled and the likelihood of requiring therapy intensification was reduced by 28% with early versus delayed initiation of metformin . another study in the united states looking at medical records for 5870 people with t2 dm found a similar pattern for early introduction of combination oral glucose early intensification was defined as addition of a second oral drug to metformin therapy within 3  months of treatment failure ( hba1c    7.5% ) and late intensification as the introduction of combination therapy 1015  months after loss of glycaemic control . people who received early intensification were 38% more likely to achieve good glycaemic control at 1.52  years than those with late intensification . in the advance trial of 11,140 patients with t2 dm , therapeutic intensification with addition of an oral glucose lowering agent doubled the chance of achieving good glycaemic control , and with intensification with insulin , the odds were increased 2.5-fold . recently published evidence highlights that many people with t2 dm do not achieve good control of blood glucose leaving them at increased and avoidable risk of serious complications . a tendency to focus on patient - related obstacles may fail to consider issues arising from the attitudes , perceptions and behaviours of healthcare providers . in particular , there are often delays in the implementation of appropriate interventions to achieve glycaemic targets due to a complex range of negative factors that exacerbate the situation . an improved understanding of these factors would better inform strategies to assist hcps in more timely treatment of inadequately controlled glycaemia . despite a wide range of therapeutic options available , insufficient numbers of people with type 2 diabetes are reaching their glycaemic targets and large numbers are exposed to prolonged periods of hyperglycaemia . a number of obstacles exist globally that must be addressed and overcome if we are to improve the outcomes for patients . despite a wide range of therapeutic options available , insufficient numbers of people with type 2 diabetes are reaching their glycaemic targets and large numbers are exposed to prolonged periods of hyperglycaemia . a number of obstacles exist globally that must be addressed and overcome if we are to improve the outcomes for patients .
background : glycaemic control is suboptimal in a large proportion of people with type 2 diabetes who are consequently at an increased and avoidable risk of potentially severe complications . we sought to explore attitudes and practices among healthcare professionals that may contribute to suboptimal glycaemic control through a review of recent relevant publications in the scientific literature.methods:an electronic search of the pubmed database was performed to identify relevant publications from january 2011 to july 2015 . 
 the electronic search was complemented by a manual search of abstracts from key diabetes conferences in 2014/2015 available online.results:recently published data indicate that glycaemic control is suboptimal in a substantial proportion ( typically 40%60% ) of people with diabetes . 
 this is the case across geographic regions and in both low- and higher - income countries . 
 therapeutic inertia appears to be an important contributor to poor glycaemic control in up to half of people with type 2 diabetes . in particular , 
 prescribers are often willing to tolerate extended periods of 
 mild 
 hyperglycaemia as well as having low expectations for their patients . 
 there are often delays of 3  years or longer in initiating or intensifying glucose - lowering therapy when needed.conclusion:many people with type 2 diabetes are failed by current management , with approximately half not achieving or maintaining appropriate target blood glucose levels , leaving these patients at increased and avoidable risk of serious complications.review criteria : the methodology of this review article is detailed in the  methods section .