The value of glycosylated hemoglobin (HbA1c) as a predictive risk factor in the diagnosis of diabetes mellitus (DM) in the elderly

Risk of progression to diabetes and mortality in older people with prediabetes: The English longitudinal study on ageing

AIMS

Prediabetes is used to identify people at increased risk for diabetes. However, the importance of prediabetes in older populations is still poorly explored. Therefore, we aimed to investigate the prevalence of prediabetes, based on either glycated haemoglobin (HbA1c) levels or fasting glucose (FG) levels, or both and the progression of prediabetes to diabetes or to mortality in older participants of the English Longitudinal Study on Ageing.

MATERIALS AND METHODS

Prediabetes was categorized based on HbA1c levels (5.7%-6.4%) and/or FG levels (5.6-7.0 mmol/L). Information regarding mortality and incident diabetes were recorded during follow-up period of 10 years.

RESULTS

In 2027 participants (mean age: 70.6 years, 55.2% females), the prevalence of prediabetes ranged between 5.9% and 31.1%. Over 8 years of follow-up, 189 participants (5.4% of the initial population) developed diabetes and 606 (17.4%) died. Among 1,403 people with HbA1c at the baseline <5.7%, 33 developed diabetes and 138 died; in contrast, among 479 participants with a diagnosis of prediabetes using a value of HbA1c between 5.7% and 6.4%, 62 developed diabetes and 56 died. Similarly, among 1,657 people with normal values of FG at baseline 60 had a diagnosis of diabetes during follow-up and 163 died, compared to 225 with FG between 5.6 mmol/L and 7.0 mmol/L in which 35 developed diabetes and 31 died.

CONCLUSION

The prevalence of prediabetes in older adults is high, but the progression from prediabetes to diabetes is uncommon, whereas the regression to normoglycemia or the progression to death was more frequent.

Risk of Progression to Diabetes Among Older Adults With Prediabetes

IMPORTANCE

The term prediabetes is used to identify individuals at increased risk for diabetes. However, the natural history of prediabetes in older age is not well characterized.

OBJECTIVES

To compare different prediabetes definitions and characterize the risks of prediabetes and diabetes among older adults in a community-based setting.

DESIGN, SETTING, AND PARTICIPANTS

In this prospective cohort analysis of 3412 older adults without diabetes from the Atherosclerosis Risk in Communities Study (baseline, 2011-2013), participants were contacted semiannually through December 31, 2017, and attended a follow-up visit between January 1, 2016, and December 31, 2017 (median [range] follow-up, 5.0 [0.1-6.5] years).

EXPOSURES

Prediabetes defined by a glycated hemoglobin (HbA1c) level of 5.7% to 6.4%, impaired fasting glucose (IFG) level (FG level of 100-125 mg/dL), either, or both.

MAIN OUTCOMES AND MEASURES

Incident total diabetes (physician diagnosis, glucose-lowering medication use, HbA1c level ≥6.5%, or FG level ≥126 mg/dL).

RESULTS

A total of 3412 participants without diabetes (mean [SD] age, 75.6 [5.2] years; 2040 [60%] female; and 572 [17%] Black) attended visit 5 (2011-2013, baseline). Of the 3412 participants at baseline, a total of 2497 participants attended the follow-up visit or died. During the 6.5-year follow-up period, there were 156 incident total diabetes cases (118 diagnosed) and 434 deaths. A total of 1490 participants (44%) had HbA1c levels of 5.7% to 6.4%, 1996 (59%) had IFG, 2482 (73%) met the HbA1c or IFG criteria, and 1004 (29%) met both the HbA1c and IFG criteria. Among participants with HbA1c levels of 5.7% to 6.4% at baseline, 97 (9%) progressed to diabetes, 148 (13%) regressed to normoglycemia (HbA1c, <5.7%), and 207 (19%) died. Of those with IFG at baseline, 112 (8%) progressed to diabetes, 647 (44%) regressed to normoglycemia (FG, <100 mg/dL), and 236 (16%) died. Of those with baseline HbA1c levels less than 5.7%, 239 (17%) progressed to HbA1c levels of 5.7% to 6.4% and 41 (3%) developed diabetes. Of those with baseline FG levels less than 100 mg/dL, 80 (8%) progressed to IFG (FG, 100-125 mg/dL) and 26 (3%) developed diabetes.

CONCLUSIONS AND RELEVANCE

In this community-based cohort study of older adults, the prevalence of prediabetes was high; however, during the study period, regression to normoglycemia or death was more frequent than progression to diabetes. These findings suggest that prediabetes may not be a robust diagnostic entity in older age.

Development of type 2 diabetes mellitus in people with intermediate hyperglycaemia

BACKGROUND

Intermediate hyperglycaemia (IH) is characterised by one or more measurements of elevated blood glucose concentrations, such as impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and elevated glycosylated haemoglobin A1c (HbA1c). These levels are higher than normal but below the diagnostic threshold for type 2 diabetes mellitus (T2DM). The reduced threshold of 5.6 mmol/L (100 mg/dL) fasting plasma glucose (FPG) for defining IFG, introduced by the American Diabetes Association (ADA) in 2003, substantially increased the prevalence of IFG. Likewise, the lowering of the HbA1c threshold from 6.0% to 5.7% by the ADA in 2010 could potentially have significant medical, public health and socioeconomic impacts.

OBJECTIVES

To assess the overall prognosis of people with IH for developing T2DM, regression from IH to normoglycaemia and the difference in T2DM incidence in people with IH versus people with normoglycaemia.

SEARCH METHODS

We searched MEDLINE, Embase, ClincialTrials.gov and the International Clinical Trials Registry Platform (ICTRP) Search Portal up to December 2016 and updated the MEDLINE search in February 2018. We used several complementary search methods in addition to a Boolean search based on analytical text mining.

SELECTION CRITERIA

We included prospective cohort studies investigating the development of T2DM in people with IH. We used standard definitions of IH as described by the ADA or World Health Organization (WHO). We excluded intervention trials and studies on cohorts with additional comorbidities at baseline, studies with missing data on the transition from IH to T2DM, and studies where T2DM incidence was evaluated by documents or self-report only.

DATA COLLECTION AND ANALYSIS

One review author extracted study characteristics, and a second author checked the extracted data. We used a tailored version of the Quality In Prognosis Studies (QUIPS) tool for assessing risk of bias. We pooled incidence and incidence rate ratios (IRR) using a random-effects model to account for between-study heterogeneity. To meta-analyse incidence data, we used a method for pooling proportions. For hazard ratios (HR) and odds ratios (OR) of IH versus normoglycaemia, reported with 95% confidence intervals (CI), we obtained standard errors from these CIs and performed random-effects meta-analyses using the generic inverse-variance method. We used multivariable HRs and the model with the greatest number of covariates. We evaluated the certainty of the evidence with an adapted version of the GRADE framework.

MAIN RESULTS

We included 103 prospective cohort studies. The studies mainly defined IH by IFG5.6 (FPG mmol/L 5.6 to 6.9 mmol/L or 100 mg/dL to 125 mg/dL), IFG6.1 (FPG 6.1 mmol/L to 6.9 mmol/L or 110 mg/dL to 125 mg/dL), IGT (plasma glucose 7.8 mmol/L to 11.1 mmol/L or 140 mg/dL to 199 mg/dL two hours after a 75 g glucose load on the oral glucose tolerance test, combined IFG and IGT (IFG/IGT), and elevated HbA1c (HbA1c5.7: HbA1c 5.7% to 6.4% or 39 mmol/mol to 46 mmol/mol; HbA1c6.0: HbA1c 6.0% to 6.4% or 42 mmol/mol to 46 mmol/mol). The follow-up period ranged from 1 to 24 years. Ninety-three studies evaluated the overall prognosis of people with IH measured by cumulative T2DM incidence, and 52 studies evaluated glycaemic status as a prognostic factor for T2DM by comparing a cohort with IH to a cohort with normoglycaemia. Participants were of Australian, European or North American origin in 41 studies; Latin American in 7; Asian or Middle Eastern in 50; and Islanders or American Indians in 5. Six studies included children and/or adolescents.Cumulative incidence of T2DM associated with IFG5.6, IFG6.1, IGT and the combination of IFG/IGT increased with length of follow-up. Cumulative incidence was highest with IFG/IGT, followed by IGT, IFG6.1 and IFG5.6. Limited data showed a higher T2DM incidence associated with HbA1c6.0 compared to HbA1c5.7. We rated the evidence for overall prognosis as of moderate certainty because of imprecision (wide CIs in most studies). In the 47 studies reporting restitution of normoglycaemia, regression ranged from 33% to 59% within one to five years follow-up, and from 17% to 42% for 6 to 11 years of follow-up (moderate-certainty evidence).Studies evaluating the prognostic effect of IH versus normoglycaemia reported different effect measures (HRs, IRRs and ORs). Overall, the effect measures all indicated an elevated risk of T2DM at 1 to 24 years of follow-up. Taking into account the long-term follow-up of cohort studies, estimation of HRs for time-dependent events like T2DM incidence appeared most reliable. The pooled HR and the number of studies and participants for different IH definitions as compared to normoglycaemia were: IFG5.6: HR 4.32 (95% CI 2.61 to 7.12), 8 studies, 9017 participants; IFG6.1: HR 5.47 (95% CI 3.50 to 8.54), 9 studies, 2818 participants; IGT: HR 3.61 (95% CI 2.31 to 5.64), 5 studies, 4010 participants; IFG and IGT: HR 6.90 (95% CI 4.15 to 11.45), 5 studies, 1038 participants; HbA1c5.7: HR 5.55 (95% CI 2.77 to 11.12), 4 studies, 5223 participants; HbA1c6.0: HR 10.10 (95% CI 3.59 to 28.43), 6 studies, 4532 participants. In subgroup analyses, there was no clear pattern of differences between geographic regions. We downgraded the evidence for the prognostic effect of IH versus normoglycaemia to low-certainty evidence due to study limitations because many studies did not adequately adjust for confounders. Imprecision and inconsistency required further downgrading due to wide 95% CIs and wide 95% prediction intervals (sometimes ranging from negative to positive prognostic factor to outcome associations), respectively.This evidence is up to date as of 26 February 2018.

AUTHORS' CONCLUSIONS

Overall prognosis of people with IH worsened over time. T2DM cumulative incidence generally increased over the course of follow-up but varied with IH definition. Regression from IH to normoglycaemia decreased over time but was observed even after 11 years of follow-up. The risk of developing T2DM when comparing IH with normoglycaemia at baseline varied by IH definition. Taking into consideration the uncertainty of the available evidence, as well as the fluctuating stages of normoglycaemia, IH and T2DM, which may transition from one stage to another in both directions even after years of follow-up, practitioners should be careful about the potential implications of any active intervention for people 'diagnosed' with IH.

Prediction of glycaemic control in young children and adolescents with type 1 diabetes mellitus using mixed-effects logistic regression modelling

OBJECTIVES

Glycaemic control in children and adolescents with type 1 diabetes mellitus can be challenging, complex and influenced by many factors. This study aimed to identify patient characteristics that were predictive of satisfactory glycaemic control in the paediatric population using a logistic regression mixed-effects (population) modelling approach.

METHODS

The data were obtained from 288 patients aged between 1 and 22 years old recorded retrospectively over 3 years (1852 HbA1c observations). HbA1c status was categorised as 'satisfactory' or 'unsatisfactory' glycaemic control, using an a priori cut-off value of HbA1c ≥ 9% (75 mmol/mol), as used routinely by the hospital's endocrine paediatricians. Patients' characteristics were tested as covariates in the model as potential predictors of glycaemic control.

RESULTS

There were three patient characteristics identified as having a significant influence on glycaemic control: HbA1c measurement at the beginning of the observation period (Odds Ratio (OR) = 0.30 per 1% HbA1c increase, 95% confidence interval (CI) = 0.20-0.41); Age (OR = 0.88 per year increase, 95% CI = 0.80-0.94), and fractional disease duration (disease duration/age, OR = 0.80 per 0.10 increase, 95% CI = 0.66-0.93) were collectively identified as factors contributing significantly to lower the probability of satisfactory glycaemic control.

CONCLUSIONS

The study outcomes may prove useful for identifying paediatric patients at risk of having unsatisfactory glycaemic control, and who could require more extensive monitoring, support, or targeted interventions.

The changing relationship between HbA1c and FPG according to different FPG ranges

PURPOSE

Since the American Diabetes Association included hemoglobin A1c (HbA1c) in the diagnostic criteria for diabetes in 2010, the clinical use of HbA1c has remained controversial. We explored the use of HbA1c for diagnosing diabetes and intermediate hyperglycemia in comparison with fasting plasma glucose (FPG).

METHODS

We screened 3710 adult subjects (mean age = 55.24 years) comprising 1704 males and 2006 females. We drew an receiver operating characteristic (ROC) curve to evaluate the ability of HbA1c to diagnose diabetes and intermediate hyperglycemia according to FPG. We used Kappa coefficient and Pearson's correlation coefficient to evaluate the relationship between HbA1c and FPG in different FPG ranges.

RESULTS

The areas under ROC curve to diagnose diabetes and intermediate hyperglycemia were 0.859 (95 % CI 0.827-0.892) and 0.633 (95 % CI 0.615-0.651). The kappa coefficients between FPG and HbA1c for diagnosis of diabetes and intermediate hyperglycemia were 0.601 (P < 0.001) and 0.104 (P < 0.001). The Pearson's correlation coefficient of FPG and HbA1c was 0.640 (P < 0.001), but when we classified FPG as normal, intermediate hyperglycemia and diabetes, the coefficients became 0.07 (P = 0.002), 0.185 (P < 0.001) and 0.760 (P < 0.001), respectively.

CONCLUSIONS

The relationship between HbA1c and FPG changed according to the different FPG ranges. When FPG was higher, the relationship was stronger. HbA1c and FPG were highly consistent in diagnosing diabetes, but they were not in predicting intermediate hyperglycemia.

Depressive symptoms and glycated hemoglobin A1c: a reciprocal relationship in a prospective cohort study

BACKGROUND

The aim of this study was to evaluate the dynamic association between depressive symptoms and glycated hemoglobin A1c (HbA1c) levels using data from the English Longitudinal Study of Ageing (ELSA).

METHOD

The sample was comprised of 2886 participants aged ⩾50 years who participated in three clinical assessments over an 8-year period (21% with prediabetes and 7% with diabetes at baseline). Structural equation models were used to address reciprocal associations between depressive symptoms and HbA1c levels and to evaluate the mediating effects of lifestyle-related behaviors and cardiometabolic factors.

RESULTS

We found a reciprocal association between depressive symptoms and HbA1c levels: depressive symptoms at one assessment point predicted HbA1c levels at the next assessment point (standardized β = 0.052) which in turn predicted depressive symptoms at the following assessment point (standardized β = 0.051). Mediation analysis suggested that both lifestyle-related behaviors and cardiometabolic factors might mediate the association between depressive symptoms and HbA1c levels: depressive symptoms at baseline predicted lifestyle-related behaviors and cardiometabolic factors at the next assessment, which in turn predicted HbA1c levels 4 years later. A similar association was observed for the other direction: HbA1c levels at baseline predicted lifestyle-related behaviors and cardiometabolic factors at the next assessment, which in turn predicted depressive symptoms 4 years later.

CONCLUSIONS

Our results suggest a dynamic relationship between depressive symptoms and HbA1c which might be mediated by both lifestyle and cardiometabolic factors. This has important implications for investigating the pathways which could link depressive symptoms and increased risk of diabetes.

A Novel TGR5 Activator WB403 Promotes GLP-1 Secretion and Preserves Pancreatic β-Cells in Type 2 Diabetic Mice

The G protein-coupled receptor TGR5 is a membrane receptor for bile acids. Its agonism increases energy expenditure and controls blood glucose through secretion of glucagon-like peptide-1 in enteroendocrine cells. In this study, we explored the therapeutic potential of WB403, a small compound activating TGR5 which was identified by combining TGR5 targeted luciferase assay and active GLP-1 assay, in treating type 2 diabetes. After confirmation of TGR5 and GLP-1 stimulating activities in various cell systems, WB403 was examined in oral glucose tolerance test, and tested on different mouse models of type 2 diabetes for glycemic control and pancreatic β-cell protection effect. As a result, WB403 exhibited a moderate TGR5 activation effect while promoting GLP-1 secretion efficiently. Interestingly, gallbladder filling effect, which was reported for some known TGR5 agonists, was not detected in this novel compound. In vivo results showed that WB403 significantly improved glucose tolerance and decreased fasting blood glucose, postprandial blood glucose and HbA1c in type 2 diabetic mice. Further analysis revealed that WB403 increased pancreatic β-cells and restored the normal distribution pattern of α-cell and β-cell in islets. These findings demonstrated that TGR5 activator WB403 effectively promoted GLP-1 release, improved hyperglycemia and preserved the mass and function of pancreatic β-cells, whereas it did not show a significant side effect on gallbladder. It may represent a promising approach for future type 2 diabetes mellitus drug development.

Hemoglobin A1c for the diagnosis of diabetes: To replace or to guide oral glucose tolerance tests?

Aims/Introduction:  To evaluate if hemoglobin A1c (A1C) can replace the use of the oral glucose tolerance test (OGTT) to diagnose diabetes in Chinese patients.

Materials and Methods:  Subjects without pre‐existing diabetes were included in this community‐based study. Each participant received a 75‐g OGTT and A1C tests.

Results:  A total of 1362 subjects, 512 men and 850 women, aged 18–88 years, were enrolled. The prevalence of diabetes was 7.4 and 7.3% by OGTT and by A1C ≥ 6.5% criteria, respectively. The optimal A1C cut‐off for diabetes defined by OGTT was 6.1%. The performance of A1C ≥ 6.1% to find diabetes by OGTT was poor, with a kappa 0.50, sensitivity 80% and specificity 91%. Using current criteria of fasting plasma glucose (FPG) < 5.56 mmol/L to exclude and ≥7 mmol/L to diagnose diabetes (FPG criterion), the sensitivity, specificity and OGTT required were 77.2, 100 and 13.5%, respectively. Using A1C < 5.9% to exclude and ≥7.0% to diagnose diabetes (A1C criterion), the sensitivity, specificity and OGTT required were 89.1, 99.8 and 26.5%, respectively. However, using FPG < 5.56 mmol/L and A1C < 6.1% to exclude, and A1C ≥ 7.0% to diagnose diabetes (A1C plus FPG criterion), the sensitivity, specificity and OGTT required were 85.2, 100 and 18.9%, respectively.

Conclusions:  To screen for diabetes, the A1C criterion is more sensitive than the FPG criterion, with more OGTT needed. The A1C plus FPG criterion reduced the number of OGTT needed with acceptable sensitivity. A1C can guide, but cannot replace, OGTT to diagnose diabetes. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2011.00181.x, 2011)

Validity of glycated hemoglobin in screening and diagnosing type 2 diabetes mellitus in Chinese subjects

BACKGROUND/AIMS

The application of glycated hemoglobin (HbA(1c)) for the diagnosis of diabetes is currently under extensive discussion. In this study, we explored the validity of using HbA(1c) as a screening and diagnostic test in Chinese subjects recruited in Nanjing, China.

METHODS

In total, 497 subjects (361 men and 136 women) with fasting plasma glucose (PG) ≥ 5.6 mmol/L were recruited to undergo the oral glucose tolerance test (OGTT) and HbA(1c) test. Plasma lipid, uric acid, and blood pressure were also measured.

RESULTS

Using a receiver operating characteristic curve, the optimal cutoff point of HbA(1c) related to diabetes diagnosed by the OGTT was 6.3%, with a sensitivity and specificity of 79.6% and 82.2%, respectively, and the area under the curve was 0.87 (95% confidence interval, 0.83 to 0.92). A HbA(1c) level of 6.5% had a sensitivity and specificity of 62.7% and 93.5%, respectively. When comparing the HbA(1c) ≥ 6.5% or OGTT methods for diagnosing diabetes, the former group had significantly higher HbA(1c) levels and lower levels of fasting and 2-hour PG than the latter group. No significant difference was observed in the other metabolism indexes between the two groups.

CONCLUSIONS

Our results suggest that HbA(1c) ≥ 6.5% has reasonably good specificity for diagnosing diabetes in Chinese subjects, which is in concordance with the American Diabetes Association recommendations.

Patterns of glycemic control using glycosylated hemoglobin in diabetics

Aim:

Till now estimation of blood glucose is the highly effective method for diagnosing diabetes mellitus but it provides a short-term picture of control. More evidence is required to prove that plasma glucose and glycosylated hemoglobin levels together gives a better estimate of glycemic control and compliance with treatment. Indian diabetes risk score (IDRS) is a simplified screening tool for identifying undiagnosed diabetic subjects, requires minimum time, and effort and can help to considerably reduce the costs of screening.

Objective:

To study patterns of glycemic control using glycosylated hemoglobin in diabetic patients. To find out correlation between levels of plasma glucose and glycosylated hemoglobin in diabetics and to calculate IDRS of the study population.

Materials and Methods:

A cross sectional study was conducted among 300 known diabetic patients attending outpatient department of a rural medical college in Haryana, India. Following standard procedures and protocols FPG and glycosylated hemoglobin were measured to find out a pattern of glycemic control in them after taking their written and informed consent. A correlation between the levels of glycosylated hemoglobin and fasting blood glucose was also calculated. These patients were made to fill a performa and their demographic and clinical risk factors were noted and based on this, their IDRS was calculated. This was done to validate the IDRS in Indian rural population.

Results:

Fifty-two percent of the population had fasting plasma glucose level between 125-150 mg/dl, 21% had this level between 151-175 mg/dl. Thirteen percent of the study subjects had HbA1C between 6.5-7.5, more than half (57.3%) had this value between 7.5-8.5, 12% and 18% had values between 8.5-9.5 and 9.5-10.5, respectively. Twelve percent of the participants had HbA1C level higher than 10.5. Correlation of fasting plasma glucose level and HbA1C was also studied and found that correlation coefficient came out to be .311. This correlation was found to be statistically significant (P = .007). Sixty-five percent of the case had IDRS higher than 60.

Conclusions:

Glycaemic control in diabetics can be better assessed with glycosylated hemoglobin and FPG together. A positive correlation between FPG and HbA1c allows for the use of HbA1c along with FPG in diagnosing type 2 DM but the two should not be used interchangeably. IDRS can be used as a screening tool for diabetes.

The role of diabetes and aging in the determinism of hypertension and the related cerebrovascular complications

Epidemiological studies carried out on a large sample (3191 elderly and 640 centenarians) with identical criteria and applying the actual diagnostic standards, have evidenced a high, statistically significant prevalence of diabetes mellitus type 2 (DMT2) (18.84%) in the elderly, as compared to the centenarians (7.50%). This aspect is correlated with the major frequency of maturity onset diabetes in elderly (MODE), compared to the centenarians, correlated also to the mortality of diabetes mellitus (DM) of long duration. The DMT2 and the aging interact in the determinism of vascular alterations, i.e., of the hypertension, and related cardio-cerebrovascular complications. The most frequently occurring hypertension in both the elderly and centenarians was always the systolic-isolated one. The prevalence of hypertension and acute myocardial infarction (AMI) was statistically significantly higher in diabetics, compared to the normoglycemic patients, in both the elderly and the centenarians. In addition, in a group of 914 elderly patients, being diabetics or normoglycemic at the start of the studies, but having neither AMI nor stroke at the baseline studies, after 5 years, these complications were more prevalent, significantly in statistical terms, in the diabetic subjects, compared to the normoglycemic ones. The increase of life-span causes an increase of the age when the aging phenomena appear, resulting in that the equal-age elderly people today are of better clinical conditions, compared to the previous periods. The increased life span with a consequent progressive aging of the population causes a worse general clinical state of the elderly population, characterized by polypathologies, frailty, and appearance of cognitive deficits or incapabilities for performing manual or instrumental activities.

Incidence of type 2 diabetes using proposed HbA1c diagnostic criteria in the european prospective investigation of cancer-norfolk cohort: implications for preventive strategies

OBJECTIVE

To evaluate the incidence and relative risk of type 2 diabetes defined by the newly proposed HbA(1c) diagnostic criteria in groups categorized by different baseline HbA(1c) levels.

RESEARCH DESIGN AND METHODS

Using data from the European Prospective Investigation of Cancer (EPIC)-Norfolk cohort with repeat HbA(1c) measurements, we estimated the prevalence of known and previously undiagnosed diabetes at baseline (baseline HbA(1c) ≥6.5%) and the incidence of diabetes over 3 years. We also examined the incidence and corresponding odds ratios (ORs) by different levels of baseline HbA(1c). Incident diabetes was defined clinically (self-report at follow-up, prescribed diabetes medication, or inclusion on a diabetes register) or biochemically (HbA(1c) ≥6.5% at the second health assessment), or both.

RESULTS

The overall prevalence of diabetes was 4.7%; 41% of prevalent cases were previously undiagnosed. Among 5,735 participants without diabetes at baseline (identified clinically or using HbA(1c) criteria, or both), 72 developed diabetes over 3 years (1.3% [95% CI 1.0-1.5]), of which 49% were identified using the HbA(1c) criteria. In 6% of the total population, the baseline HbA(1c) was 6.0-6.4%; 36% of incident cases arose in this group. The incidence of diabetes in this group was 15 times higher than in those with a baseline HbA(1c) of <5.0% (OR 15.5 [95% CI 7.2-33.3]).

CONCLUSIONS

The cumulative incidence of diabetes defined using a newly proposed HbA(1c) threshold in this middle-aged British cohort was 1.3% over 3 years. Targeting interventions to individuals with an HbA(1c) of 6.0-6.4% might represent a feasible preventive strategy, although complementary population-based preventive strategies are also needed to reduce the growing burden of diabetes.