***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Aims /hypothesisOur objectives were to explore whether the phenomenon of  HbA1c ‘ tracking  ’ occurs in individuals with type 1 diabetes , how long after diagnosis does tracking take to stabilise , and whether there is an effect of sex and age at diagnosis on tracking . Methods A total of 4525 individuals diagnosed with type 1 diabetes between 1 January 1995 and 1 May 2015 were identified from The Health Improvement Network ( THIN ) data base . Mixed models were applied to assess the variability of HbA1c levels over time with r and om effects on general practice s ( primary care units ) and individuals within practice s. Results 4525 individuals diagnosed with type 1 diabetes were identified in THIN over the study period . The greatest difference in mean HbA1c measurement ( −7.0 [ 95 % CI −8.0 , −6.1 ] mmol/mol [ 0.6 % ] ) was seen when comparing measurements made immediately after diagnosis ( 0–1 year since diagnosis ) with those at 10 or more years ( the reference category ) . The mean difference in HbA1c for the successive periods compared with 10 or more years after diagnosis declined and was no longer statistically significant after 5 years . In the stratified analysis using sex and age group there was considerable heterogeneity with adult onset type 1 diabetes appearing to track earlier and at a lower mean HbA1c . Conclusions /interpretationIn individuals with type 1 diabetes  , glycaemic control measured by HbA1c settles onto a long-term ‘ track ’ and this occurs on average by 5 years following diagnosis . Age at diagnosis modifies both the rate at which individuals settle into their track and the absolute HbA1c tracking level for the next 10 years Objective To determine the completeness and diagnostic validity of myocardial infa rct ion recording across four national health record sources in primary care , hospital care , a disease registry , and mortality register . Design Cohort study . Participants 21 482 patients with acute myocardial infa rct ion in Engl and between January 2003 and March 2009 , identified in four prospect ively collected , linked electronic health record sources : Clinical Practice Research Data link ( primary care data ) , Hospital Episode Statistics ( hospital admissions ) , the disease registry MINAP ( Myocardial Ischaemia National Audit Project ) , and the Office for National Statistics mortality register ( cause specific mortality data ) . Setting One country ( Engl and ) with one health system ( the National Health Service ) . Main outcome measures Recording of acute myocardial infa rct ion , incidence , all cause mortality within one year of acute myocardial infa rct ion , and diagnostic validity of acute myocardial infa rct ion compared with electrocardiographic and troponin findings in the disease registry ( gold st and ard ) . Results Risk factors and non-cardiovascular coexisting conditions were similar across patients identified in primary care , hospital admission , and registry sources . Immediate all cause mortality was highest among patients with acute myocardial infa rct ion recorded in primary care , which ( unlike hospital admission and disease registry sources ) included patients who did not reach hospital , but at one year mortality rates in cohorts from each source were similar . 5561 ( 31.0 % ) patients with non-fatal acute myocardial infa rct ion were recorded in all three sources and 11 482 ( 63.9 % ) in at least two sources . The crude incidence of acute myocardial infa rct ion was underestimated by 25 - 50 % using one source compared with using all three sources . Compared with acute myocardial infa rct ion defined in the disease registry , the positive predictive value of acute myocardial infa rct ion recorded in primary care was 92.2 % ( 95 % confidence interval 91.6 % to 92.8 % ) and in hospital admissions was 91.5 % ( 90.8 % to 92.1 % ) . Conclusion Each data source missed a substantial proportion ( 25 - 50 % ) of myocardial infa rct ion events . Failure to use linked electronic health records from primary care , hospital care , disease registry , and death certificates may lead to biased estimates of the incidence and outcome of myocardial infa rct ion . Trial registration NCT01569139 clinical trials.gov Type 1 diabetic patients have a pronounced risk of premature coronary artery disease and death . We sought to evaluate the prevalence of silent coronary atheromatosis and to evaluate the relation between coronary atheromatosis and glycemic control . Coronary atheromatosis was evaluated in type 1 diabetic patients with no symptoms of coronary artery disease by exercise electrocardiogram ( ECG ) in 39 patients and quantitative coronary angiography and by intravascular ultrasound ( IVUS ) examinations in 29 patients . The findings from the IVUS examinations were related to mean HbA(1c ) collected prospect ively over 18 years . Abnormal exercise ECGs were found in 15 % of patients , and angiographic diameter stenosis of > 50 % in one or more of the main coronary arteries was found in 34 % of patients . All patients examined with intracoronary ultrasound had developed atherosclerotic plaques with an increased intimal thickness ( > 0.5 mm ) in one or more of the coronary arteries . Coronary artery plaque formation , as judged by ultrasound , was significantly related to mean HbA(1c ) during 18 years ( P < 0.05 ) after adjustment for total cholesterol and age . This study demonstrates a high prevalence of silent coronary atheromatosis in type 1 diabetic patients with no symptoms of coronary heart disease . Long-term glycemic control was shown to be associated with coronary atheromatosis OBJECTIVE —To reevaluate the persistence and stability of previously observed differences between pediatric diabetes centers and to investigate the influence of demography , language communication problems , and changes in insulin regimens on metabolic outcome , hypoglycemia , and ketoacidosis . RESEARCH DESIGN AND METHODS —This was an observational cross-sectional international study in 21 centers , with clinical data obtained from all participants and A1C levels assayed in one central laboratory . All individuals with diabetes aged 11–18 years ( 49.4 % female ) , with duration of diabetes of at least 1 year , were invited to participate . Fourteen of the centers participated in previous Hvidoere Studies , allowing direct comparison of glycemic control across centers between 1998 and 2005 . RESULTS —Mean A1C was 8.2 ± 1.4 % , with substantial variation between centers ( mean A1C range 7.4–9.2 % ; P < 0.001 ) . There were no significant differences between centers in rates of severe hypoglycemia or diabetic ketoacidosis . Language difficulties had a significant negative impact on metabolic outcome ( A1C 8.5 ± 2.0 % vs. 8.2 ± 1.4 % for those with language difficulties vs. those without , respectively ; P < 0.05 ) . After adjustement for significant confounders of age , sex , duration of diabetes , insulin regimen , insulin dose , BMI , and language difficulties , the center differences persisted , and the effect size for center was not reduced . Relative center ranking since 1998 has remained stable , with no significant change in A1C . CONCLUSIONS —Despite many changes in diabetes management , major differences in metabolic outcome between 21 international pediatric diabetes centers persist . Different application between centers in the implementation of insulin treatment appears to be of more importance and needs further exploration BACKGROUND Intensive diabetes therapy aim ed at achieving near normoglycemia reduces the risk of microvascular and neurologic complications of type 1 diabetes . We studied whether the use of intensive therapy as compared with conventional therapy during the Diabetes Control and Complications Trial ( DCCT ) affected the long-term incidence of cardiovascular disease . METHODS The DCCT r and omly assigned 1441 patients with type 1 diabetes to intensive or conventional therapy , treating them for a mean of 6.5 years between 1983 and 1993 . Ninety-three percent were subsequently followed until February 1 , 2005 , during the observational Epidemiology of Diabetes Interventions and Complications study . Cardiovascular disease ( defined as nonfatal myocardial infa rct ion , stroke , death from cardiovascular disease , confirmed angina , or the need for coronary-artery revascularization ) was assessed with st and ardized measures and classified by an independent committee . RESULTS During the mean 17 years of follow-up , 46 cardiovascular disease events occurred in 31 patients who had received intensive treatment in the DCCT , as compared with 98 events in 52 patients who had received conventional treatment . Intensive treatment reduced the risk of any cardiovascular disease event by 42 percent ( 95 percent confidence interval , 9 to 63 percent ; P=0.02 ) and the risk of nonfatal myocardial infa rct ion , stroke , or death from cardiovascular disease by 57 percent ( 95 percent confidence interval , 12 to 79 percent ; P=0.02 ) . The decrease in glycosylated hemoglobin values during the DCCT was significantly associated with most of the positive effects of intensive treatment on the risk of cardiovascular disease . Microalbuminuria and albuminuria were associated with a significant increase in the risk of cardiovascular disease , but differences between treatment groups remained significant ( P < or = 0.05 ) after adjusting for these factors . CONCLUSIONS Intensive diabetes therapy has long-term beneficial effects on the risk of cardiovascular disease in patients with type 1 diabetes Background The prognosis for young people diagnosed with diabetes during childhood remains poor and this is mainly related to the long-term risk of developing vascular complications . Microalbuminuria identifies subjects at risk for diabetic nephropathy ( DN ) and cardiovascular disease ( CVD ) . It is often detected in adolescence but is rarely treated before the age of 18 years , as at the end of puberty albumin excretion may decline and in some subjects will return into the normal range . However , evidence indicates that subjects with both transient and persistent microalbuminuria have experienced renal damage during puberty and thus reno-protection to prevent long-term complications is warranted . In adults with diabetes and microalbuminuria , the use of angiotensin converting enzyme inhibitors ( ACEI ) and Statins is increasing , and in order to determine whether these agents are of value in the adolescent population a large r and omized controlled clinical trial is needed . Methods / Design The Adolescent type 1 Diabetes cardio-renal Intervention Trial ( AdDIT ) is a multi-center , r and omized , double-blind , placebo-controlled trial of ACEI and Statin therapy in adolescents with type 1 diabetes . 500 high-risk adolescents , defined on the basis of their albumin excretion , are r and omized to receive either ACEI ( Quinapril ) or Statins ( Atorvastatin ) or combination therapy or placebo for 3 - 4 years . There will also be a parallel open observational study , based on the follow-up of 400 low-risk non-r and omized adolescents . The major endpoint of the study is the change in albumin excretion ; secondary endpoints include markers of CVD , renal function , retinopathy , quality of life combined with assessment of compliance and potential health economic benefits . Discussion AdDIT will provide important data on the potential renal and cardiovascular protective effects of ACEI and Statins in high-risk adolescents . Long-term follow-up of the r and omized subjects will provide direct evidence of disease outcomes , in addition to the data on early surrogate measures of DN and CVD . Follow-up of non-r and omized low-risk subjects will determine the potential impact of intervention on DN and CVD . AdDIT will help to determine whether , in addition to encouraging young people to achieve good glycaemic control , pharmacological cardio-renal protection should also be implemented . EudraCT Number 2007 - 001039 - 72 Trial Registration Number IS RCT The Diabetes Control and Complications Trial ( DCCT ) ( 1 ) and its observational follow-up , the Epidemiology of Diabetes Interventions and Complications ( EDIC ) Study ( 2 ) , are celebrating the 30th anniversary since the start of the DCCT and 20th since the reporting of the DCCT primary results ( 3 ) . During the past three decades , our underst and ing of the relationship between metabolic control and complications and the treatment of type 1 diabetes ( T1D ) has been transformed by the results of DCCT/EDIC . Most importantly , the long-term prospect s for patients have dramatically improved with the adoption of intensive therapy design ed to achieve near-normal glycemia as the st and ard of care of T1D . In this Perspective , we present an overview of the major scientific advances provided by the DCCT/EDIC Research Group , the result ing changes in therapy that have improved long-term outcomes in patients with T1D worldwide , and the challenges that remain . # # # Background and rationale . After the introduction of insulin therapy in 1922 , type 1 diabetes ( T1D ) was transformed from a uniformly fatal disease to a chronic degenerative one ( 4 ) . During the 1930–1960s , the development of chronic complications affecting the eyes , kidneys , peripheral and autonomic nervous system , and a substantially increased risk of cardiovascular disease ( C 
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INTERPRETATIONS Glycemic control after the first few months of childhood onset T1D , remains stable but sub-optimal for a decade .
The low and high HbA1c levels at baseline seem to " track " in their respective tracks during the 10-year follow-up , however , the initial difference between groups narrows over time .