Hemoglobin A1c as a predictor of incident diabetes

Impact of Primary Care Worksite Health and Wellness Clinics on HbA1c Level Among Prediabetic or Diabetic Employees

PURPOSE

To determine whether the use of worksite health and wellness clinics reduced hemoglobin A1c (HbA1c) for prediabetic and diabetic employees.

DESIGN

Hemoglobin A1c values were compared between clinic users and matched non-users.

SETTING

The Wonderful Company's (TWC's) agricultural and packaging sites in Central California.

SAMPLE

TWC's 2016 to 2017 employees who used clinics (n = 445, defined below) and clinic non-users (n = 217) who had HbA1c screening and worked at TWC for 3 or more months each year.

INTERVENTION

A unique worksite health and wellness clinic that offers multidisciplinary primary medical care in synergy with TWC's overall wellness programs.

MEASURES

Exposure was clinic use, defined by frequency and patterns of visits. Hemoglobin A1c was the outcome of interest.

ANALYSIS

Users and non-users were propensity score matched using the 2016 employee data including HbA1c, and then 2017 HbA1c values were compared between the 2 groups.

RESULTS

The 2017 HbA1c of diabetic employees was lower among clinic users compared to non-users (7.42 vs 8.53, P < .001). Differences in HbA1c among prediabetics or diabetics and prediabetics aggregated were not statistically significant, despite TWC's population-level data showing a reduction in prediabetes prevalence. The clinic impact results were robust to multivariate analyses and an alternative definition of utilization.

CONCLUSION

The implementation of TWC's Health and Wellness clinics was associated with reductions in HbA1c among diabetics, but further research is needed on prediabetics.

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.

Renoprotective Effect of Angiotensin-Converting Enzyme Inhibitors and Angiotensin II Receptor Blockers in Diabetic Patients with Proteinuria

BACKGROUND/AIMS

Limited evidence exists on the choice of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs) in diabetic patients with nephropathy. We aim to assess the renal effectiveness and safety of these drugs among diabetic nephropathy patients.

METHODS

This retrospective cohort study was conducted with diabetic nephropathy patients who initiated ACEI or ARB monotherapy. The primary outcome was a composite of end stage of renal disease and renal transplantation, and the secondary outcome was all-cause mortality. The safety endpoint was hyperkalemia.

RESULTS

Three thousand seven hundred and thirty-nine ACEI users and 3,316 ARB users were identified. ARBs seemed to be inferior to ACEIs given their poorer renal outcome (HR 1.31; 95% CI, 1.15-1.50) and higher risk of hyperkalemia (HR 1.17; 95% CI, 1.04-1.32). Among the four ACEIs compared, captopril was an inferior treatment choice given its poorer renal outcomes (HR 1.42; 95% CI, 1.05-1.93) and higher mortality rate (HR 1.25; 95% CI, 1.01-1.55). Irbesartan appeared to be a poorer treatment choice among the three ARBs compared, given its inferior renal protective effect (HR 1.35; 95% CI, 1.03-1.78).

CONCLUSIONS

Our findings suggest ACEIs as a relatively more renoprotective and safer treatment as compared to ARBs. Captopril and irbesartan may be inferior to the other ACEIs and ARBs respectively.

High Incidence of Diabetes Mellitus Among a Middle-Aged Population in Iran: A Longitudinal Study

OBJECTIVES

There are few data concerning the incidence rates of diabetes in Iran. This study aimed to determine the incidence of diabetes and its risk factors in a middle-aged population in Iran.

METHODS

All of the people who participated in the first phase of the Shahroud eye cohort study were invited to the study in 2014; after signing informed consent forms, a total of 4737 people 45 to 69 years of age were enrolled in the second phase of the study (participation rate: 91.3%). The 5-year incidence rate of diabetes was determined by age and sex, and we used the binomial logistic regression model to calculate the risk ratio.

RESULTS

The prevalence of diabetes in the second phase was 20.19% in men, 26.45% in women and 23.89% in the total group. The 5-year incidence of diabetes was 11.19% in men, 15.55% in women and 13.73% in both sexes. With increases in age, the incidence of diabetes rose in both sexes. Age (risk ratio [RR]: 1.02; CI 95%: 1.01 to 1.03) hypertension (RR: 1.41; CI 95%: 1.15 to 1.74), being overweight (RR: 2.17; CI 95%: 1.64 to 2.88) and obesity (RR: 3.4; CI 95%: 2.53 to 4.41) were associated with increased risks for the incidence of diabetes.

CONCLUSIONS

This study is 1 of the few studies in Iran that has reported the incidence of diabetes. Because the incidence of diabetes was high in the studied population, it is necessary for the health system to design and implement emergency intervention to prevent further spread of diabetes and its complications.

Opportunities and challenges in developing risk prediction models with electronic health records data: a systematic review

OBJECTIVE

Electronic health records (EHRs) are an increasingly common data source for clinical risk prediction, presenting both unique analytic opportunities and challenges. We sought to evaluate the current state of EHR based risk prediction modeling through a systematic review of clinical prediction studies using EHR data.

METHODS

We searched PubMed for articles that reported on the use of an EHR to develop a risk prediction model from 2009 to 2014. Articles were extracted by two reviewers, and we abstracted information on study design, use of EHR data, model building, and performance from each publication and supplementary documentation.

RESULTS

We identified 107 articles from 15 different countries. Studies were generally very large (median sample size = 26 100) and utilized a diverse array of predictors. Most used validation techniques (n = 94 of 107) and reported model coefficients for reproducibility (n = 83). However, studies did not fully leverage the breadth of EHR data, as they uncommonly used longitudinal information (n = 37) and employed relatively few predictor variables (median = 27 variables). Less than half of the studies were multicenter (n = 50) and only 26 performed validation across sites. Many studies did not fully address biases of EHR data such as missing data or loss to follow-up. Average c-statistics for different outcomes were: mortality (0.84), clinical prediction (0.83), hospitalization (0.71), and service utilization (0.71).

CONCLUSIONS

EHR data present both opportunities and challenges for clinical risk prediction. There is room for improvement in designing such studies.

Newly detected abnormal glucose regulation and long-term prognosis after acute myocardial infarction: Comparison of an oral glucose tolerance test and glycosylated haemoglobin A1c

BACKGROUND

An oral glucose tolerance test (OGTT) and/or glycosylated haemoglobin A1c (HbA1c) in patients with acute myocardial infarction (AMI) identify patients with increased mortality risk, but no comparison of the long-term prognostic values has yet been investigated.

METHODS

This study was a prospective cohort enrolling patients with AMI between 2002 until 2008 and follow-up until 1st October, 2012. Patients without known diabetes mellitus (DM) underwent an OGTT. Seventy-nine patients with known DM did not have an OGTT performed. Primary endpoint was all-cause mortality. We included 548 patients with AMI, of whom 469 underwent a standardized OGTT and were stratified according to OGTT and HbA1c.

RESULTS

During 9.8years of follow-up, 179 (33%) patients died. In patients having increased HbA1c ≥6.5%, a significantly increased mortality was observed (Hazard Ratio (HR) 1.60 [1.09-2.34]). However, when adjusting for known DM, no significance was detected. An OGTT did not show a significantly increased mortality, if used separately. A combined estimate showed a significantly increased mortality in patients categorized as newly diagnosed DM by OGTT and HbA1c<6.5% (HR 1.56 [95% CI 1.07-2.30]) compared to patients categorized as normal/impaired fasting glycaemia/impaired glucose tolerance by OGTT and HbA1c <6.5%. Approximately 50% of the patients with newly diagnosed DM by OGTT were only detected due to 2-hour post-load glucose values.

CONCLUSION

An OGTT is recommended in AMI patients without known DM and HbA1c<6.5%. Patients categorized as newly diagnosed DM by OGTT although HbA1c <6.5% share the same high risk of mortality as patients with HbA1c≥6.5%.

Point-of-care capillary HbA1c measurement in the emergency department: a useful tool to detect unrecognized and uncontrolled diabetes

Background

Inpatient hyperglycaemia and diabetes mellitus (DM) are common and are associated with an increased risk of complications and mortality. The severity of hyperglycaemia determines the rate of complications in patients treated in the emergency department (ED). Our aim was to examine whether determination of the capillary haemoglobin A1c (HbA1c) is a reliable method for detecting unknown diabetes and poor glycaemic control in the ED.

Methods

A prospective observational study was conducted in adult (>18 years) patients treated in a single-centre ED. We compared the results of HbA1c levels measured by Bio-Rad in2it point-of-care device on a capillary blood sample and by the hospital laboratory.

Results

A total of 187 ED patients with an average age of 57.1 ± 19.2 years were studied. The mean HbA1c value was 5.78 ± 1.26 % by capillary POC testing and 6.10 ± 1.12 % by the hospital laboratory (correlation = 0.712, P < 0.001). A total of 17.1 % of cases had a prior diagnosis of DM. The diagnosis of DM (plasma glucose > 126 mg/dL and/or HbA1c > 6.5 %) was made in ten (5.4 %) additional cases (prior undiagnosed DM) for a total prior DM prevalence of 22.5 % (95 % CI 16.4–28.5 %). Capillary HbA1c detected 11 additional cases of unknown DM (5.9 %). A capillary HbA1c value greater than 6 % has a sensitivity of 85.7 % and specificity of 85.3 % for the screening of DM.

Conclusions

Determination of the capillary HbA1c in the ED is a reliable, fast, and simple system for the screening of unknown or uncontrolled DM.

Incidence of type 2 diabetes and associated factors in the adult population of the Community of Madrid. PREDIMERC cohort

OBJECTIVES

Determine the incidence and risk factors of type2 diabetes in the adult population of Madrid (Spain) and compare the predictive models of type2 diabetes based on the prediabetes criteria of the American Diabetes Association (ADA) and the World Health Organisation (WHO).

MATERIAL AND METHODS

A prospective study was conducted on a population cohort composed of 2048 individuals between 30 and 74years of age with no diabetes. At the start of the study, an epidemiological survey was performed, and baseline glycaemia, HbA1c, body mass index and waist circumference were measured. A follow-up of 6.4years was conducted. New cases of type2 diabetes were identified using the electronic primary care medical history.

RESULTS

The incidence of type2 diabetes was 3.5 cases/1000 person-years. In the multivariate analysis, the variables that were associated with the onset of type2 diabetes were age, family history of diabetes, baseline glycaemia (100-125mg/dL), HbA1c (5.7-6.4%) and waist circumference (≥94cm for men and ≥80cm for women). Of these, the most significantly associated variables were baseline glycaemia and HbA1c. The ADA and WHO criteria for defining prediabetes had the same predictive capacity.

CONCLUSION

The incidence of type2 diabetes measured in Madrid was lower than that found in other population studies, with the glucometabolic state the main factor associated with progression to type2 diabetes. There were no differences between the prediabetes defined by the ADA and the WHO for predicting the onset of the disease.

Incidence of type 2 diabetes in pre-diabetic Japanese individuals categorized by HbA1c levels: a historical cohort study

Objective

Reported incidence of type 2 diabetes estimated at the pre-diabetic stage differs widely (2.3–18.1% per year). Because clinicians need to know the risk of incident diabetes after a diagnosis of pre-diabetes, our objective was to estimate precise incidence of diabetes using baseline HbA_1c levels.

Methods

A historical cohort study using electronic medical record data obtained between January 2008 and December 2013. A total of 52,781 individuals with HbA_1c < 6.5% were assigned to one of six groups categorized by baseline HbA_1c level: ≤ 5.5% (n=34,616), 5.6–5.7% (n=9,388), 5.8–5.9% (n=4,664), 6.0–6.1% (n= 2,338), 6.2–6.3% (n=1,257), and 6.4% (n=518). Participants were tracked until a subsequent diagnosis of diabetes or end of follow-up during a period of 5 years.

Results

During the follow-up period (mean 3.7 years), 4,369 participants developed diabetes. The incidence of diabetes in the first year was 0.7, 1.5, 2.9, 9.2, 30.4, and 44.0% in the six HbA_1c groups, respectively. At five years the incidence was 3.6, 8.9, 13.8, 27.5, 51.6, and 67.8%, respectively (p < 0.0001 comparing the HbA_1c ≤5.5% group to the other groups). After adjustment for confounding factors, the hazard ratios compared with the HbA_1c ≤5.5% group were significantly elevated: 2.3 (95%CI 2.0–2.5), 3.4 (95%CI 2.9–3.7), 8.8 (95%CI 8.0–10.1), 26.3 (95%CI 23.3–30.1), and 48.7 (95%CI 40.8–58.1) in the five HbA_1c groups (p < 0.0001).

Conclusion

By fractionating baseline HbA_1c levels into narrower HbA_1c range groups, accuracy of estimating the incidence of type 2 diabetes in subsequent years was increased. The risk of developing diabetes increased with increasing HbA_1c levels, especially with the HbA_1c level ≥ 6.2% in the first follow-up year.

Using hemoglobin A1C as a predicting model for time interval from pre-diabetes progressing to diabetes

OBJECTIVE

The early identification of subjects at high risk for diabetes is essential, thus, random rather than fasting plasma glucose is more useful. We aim to evaluate the time interval between pre-diabetes to diabetes with anti-diabetic drugs by using HbA1C as a diagnostic tool, and predicting it using a mathematic model.

METHODS

We used the Taipei Medical University Affiliated Hospital Patient Profile Database (AHPPD) from January-2007 to June-2011. The patients who progressed and were prescribed anti-diabetic drugs were selected from AHPPD. The mathematical model used to predict the time interval of HbA1C value ranged from 5.7% to 6.5% for diabetes progression.

RESULTS

We predicted an average overall time interval for all participants in between 5.7% to 6.5% during a total of 907 days (standard error, 103 days). For each group found among 5.7% to 6.5% we determined 1169.3 days for the low risk group (i.e. 3.2 years), 1080.5 days (i.e. 2.96 years) for the increased risk group and 729.4 days (i.e. 1.99 years) for the diabetes group. This indicates the patients will take an average of 2.49 years to reach 6.5%.

CONCLUSION

This prediction model is very useful to help prioritize the diagnosis at an early stage for targeting individuals with risk of diabetes. Using patients' HbA1C before anti-diabetes drugs are used we predicted the time interval from pre-diabetes progression to diabetes is 2.49 years without any influence of age and gender. Additional studies are needed to support this model for a long term prediction.

Significance of HbA1c and its measurement in the diagnosis of diabetes mellitus: US experience

The 2014 American Diabetes Association guidelines denote four means of diagnosing diabetes. The first of these is a glycosylated hemoglobin (HbA1c) >6.5%. This literature review summarizes studies (n=47) in the USA examining the significance, strengths, and limitations of using HbA1c as a diagnostic tool for diabetes, relative to other available means. Due to the relatively recent adoption of HbA1c as a diabetes mellitus diagnostic tool, a hybrid systematic, truncated review of the literature was implemented. Based on these studies, we conclude that HbA1c screening for diabetes has been found to be convenient and effective in diagnosing diabetes. HbA1c screening is particularly helpful in community-based and acute care settings where tests requiring fasting are not practical. Using HbA1c to diagnose diabetes also has some limitations. For instance, HbA1c testing may underestimate the prevalence of diabetes, particularly among whites. Because this bias differs by racial group, prevalence and resulting estimates of health disparities based on HbA1c screening differ from those based on other methods of diagnosis. In addition, existing evidence suggests that HbA1c screening may not be valid in certain subgroups, such as children, women with gestational diabetes, patients with human immunodeficiency virus, and those with prediabetes. Further guidelines are needed to clarify the appropriate use of HbA1c screening in these populations.

The usefulness of glycated hemoglobin A1c (HbA1c) for identifying dysglycemic states in individuals without previously diagnosed diabetes

PURPOSE

We investigated HbA1c's validity as a screening parameter for excluding dysglycemic states in the studied population.

MATERIAL/METHODS

Sensitivity and specificity of HbA1c in some cut-off points were compared with diagnoses based on the oral glucose tolerance test (OGTT) in individuals diagnosed between 2009-2010. Receiver operating characteristic (ROC) analysis for HbA1c was conducted. HbA1c and OGGT measures were done in 441 people (253 women, 187 men, average age 40.1 years (18-79 years)). Based on the OGGT test 37 individuals were diagnosed as diabetic, 28 as impaired glucose tolerant (IGT) and 63 as having impaired fasting glycemia (IFG).

RESULTS

A cut-off value of 6.5% HbA1c classifies diabetic subjects with a sensitivity of 45.9% and specificity of 97.5%. In the investigated population the best cut-off point (the highest sum of the sensitivity and specificity) was 5.9% HbA1c (sensitivity 86.6%, specificity 73%). HbA1c values excluding the risk of dysglycemic states have shown false negative rate in 31.9% when HbA1c was 5.5% and 10.6% when HbA1c was 5.0%.

CONCLUSIONS

Our results indicate that in the investigated population the evaluation of the prevalence of type 2 diabetes using HbA1c values proposed by the American Diabetes Association (ADA) has unsatisfactory sensitivity and detects less than a half of cases of diabetes based on the OGTT diagnoses. HbA1c 5.7% does not have sufficient specificity to identify individuals not being at risk of any disorder of glucose metabolism.

Metabolic syndrome and its components among obese (BMI >=95th) Mexican adolescents

The aim of this study was to estimate the prevalence of metabolic syndrome (MS) and its components in obese Mexican adolescents and to compare the clinical, anthropometric, and biochemical characteristics between patients with and without MS by sex. We conducted a cross-sectional study with a sample of 110 obese adolescents (boys and girls) from 8 to 16 years old (BMI ≥95th percentile), who were recruited in the pediatric obesity clinic of a third-level care hospital. A frequency analysis was used to estimate the prevalence of MS and its components, and the assessments were compared between the sexes and between the groups with and without MS using the Kruskal-Wallis test. The prevalence of MS was 62%. IN ORDER OF PREVALENCE, THE FOLLOWING COMPONENTS OF MS WERE OBSERVED IN THE SAMPLE: abdominal obesity (88%), high triglycerides (TG) (85%), low HDL-C (60%), hypertension (35%), and hyperglycemia (5%). In the groups with MS, hypertension (P<0.001), waist circumference (P=0.003), and TG (P=0.012) were significantly higher, and HDL-C (P<0.001) was significantly lower. In conclusion the prevalence of MS and its components is high among obese Mexican-Hispanic children. These findings show the importance of preventing and treating obesity in the early stages of life in order to decrease the incidence rates of cardiovascular disease and type 2 diabetes mellitus.

Metabolic syndrome is a poor predictor of diabetes in a Japanese health screening population

OBJECTIVE

Although metabolic syndrome (MS) is considered to be a predictor of diabetes and cardiovascular disease, its value for predicting diabetes beyond the levels of fasting glucose (FG) and hemoglobin A1c (HbA1c) remains questionable. In this study, we evaluated the usefulness of MS and Japanese MS (JMS) as predictors of diabetes.

METHODS

This study is a longitudinal study using data for 2,034 subjects who visited our Medical Check-up Center in both 2008 and 2011 and were free from diabetes at baseline. The odds ratios (ORs) of developing diabetes in 2011 for MS and JMS were calculated after being adjusted for FG, age, sex and antihypertensive and antihyperlipidemic medication use, then further adjusted for HbA1c. The optimal cutoff points for FG, HbA1c and body mass index (BMI) to discriminate the development of diabetes and their sensitivities/specificities were obtained from receiver operating characteristic curves. These sensitivities/specificities were compared with the sensitivities/specificities of MS and JMS.

RESULTS

The ORs (95% confidence intervals (CIs)) of developing diabetes for MS and JMS were 1.36 (0.57-3.23) (p=0.484) and 3.23 (1.25-8.36) (p=0.016), respectively, after being adjusted for FG and 1.06 (0.39-2.86) (p=0.915) and 2.34 (0.79-6.95) (p=0.126), respectively, after being further adjusted for HbA1c. The sensitivities/specificities of FG, HbA1c, BMI, MS and JMS were 0.625/0.897, 0.828/0/919, 0.625/0.734, 0.375/0.911, and 0.375/0.941, respectively.

CONCLUSION

MS and JMS were found to be poor predictors of diabetes in a Japanese health screening population.

Development of a new scoring system for predicting the 5 year incidence of type 2 diabetes in Japan: the Toranomon Hospital Health Management Center Study 6 (TOPICS 6)

AIMS/HYPOTHESIS

The aims of this study were to assess the clinical significance of introducing HbA(1c) into a risk score for diabetes and to develop a scoring system to predict the 5 year incidence of diabetes in Japanese individuals.

METHODS

The study included 7,654 non-diabetic individuals aged 40-75 years. Incident diabetes was defined as fasting plasma glucose (FPG) ≥7.0 mmol/l, HbA(1c) ≥6.5% (48 mmol/mol) or self-reported clinician-diagnosed diabetes. We constructed a risk score using non-laboratory assessments (NLA) and evaluated improvements in risk prediction by adding elevated FPG, elevated HbA(1c) or both to NLA.

RESULTS

The discriminative ability of the NLA score (age, sex, family history of diabetes, current smoking and BMI) was 0.708. The difference in discrimination between the NLA + FPG and NLA + HbA(1c) scores was non-significant (0.836 vs 0.837; p = 0.898). A risk score including family history of diabetes, smoking, obesity and both FPG and HbA(1c) had the highest discrimination (0.887, 95% CI 0.871, 0.903). At an optimal cut-off point, sensitivity and specificity were high at 83.7% and 79.0%, respectively. After initial screening using NLA scores, subsequent information on either FPG or HbA(1c) resulted in a net reclassification improvement of 42.7% or 52.3%, respectively (p < 0.0001). When both were available, net reclassification improvement and integrated discrimination improvement were further improved at 56.7% (95% CI 47.3%, 66.1%) and 10.9% (9.7%, 12.1%), respectively.

CONCLUSIONS/INTERPRETATION

Information on HbA(1c) or FPG levels after initial screening by NLA can precisely refine diabetes risk reclassification.

Assessing systemic disease risk in a dental setting: a public health perspective

Screening and monitoring for systemic disease risk in a dental setting are valuable components for more effective disease prevention and control and health care delivery. This strategy can identify patients at increased risk of disease yet unaware of their increased risk and who may benefit from proven prevention/intervention strategies. The involvement of oral health care professionals in strategies to identify individuals at risk for coronary heart disease and diabetes will extend preventive and screening efforts necessary to slow the development of these diseases, and provide a portal for individuals who do not see a physician on a regular basis to enter into the general health care system.

Relationship between glycated hemoglobin and glucose concentrations in the adult Galician population: selection of optimal glycated hemoglobin cut-off points as a diagnostic tool of diabetes mellitus

AIMS/HYPOTHESIS

To analyze the relationship between glucose and glycated hemoglobin (HbA(1c)) in the adult Galician population, evaluate the use of HbA(1c) for the screening and diagnosis of diabetes, and calculate the diagnostic threshold required for this purpose.

METHODS

We analyzed data on 2848 subjects (aged 18-85 years) drawn from a study undertaken in 2004 to assess the prevalence of diabetes in Galicia. For study purposes, diabetes was defined using the criteria recommended in 2002. Participants were classified into four glucose-based groups. The relationship between glucose and HbA(1c) was described using linear regression models, generalized additive models and Spearman's correlation. Diagnostic capacity was assessed, and optimal HbA(1c) cut-off points were calculated as a diabetes marker using the receiver operating characteristic curve.

RESULTS

Prevalence of pre-diabetes, unknown diabetes and known diabetes was 20.86, 3.37 and 4.39%, respectively. The correlations between HbA(1c) and fasting glucose were higher than those obtained for HbA(1c) and glycemia at 2h of the oral glucose overload (0.344 and 0.270, respectively). Taking glucose levels as the gold standard, a greater discriminatory capacity was obtained for HbA(1c) (area under de cruve: 0.839, 95% confidence intervals: 0.788-0.890). Based on the study criteria, the optimal minimum and maximum HbA(1c) values were 5.9% and 6.7%, respectively.

CONCLUSIONS/INTERPRETATION

HbA(1c) did not prove superior to glycemia for diagnosis of diabetes in the adult Galician population, and cannot therefore be used to replace the oral glucose tolerance test for screening and diagnosis purposes. Indeed, determination of glucose is essential to verify the diagnosis in the majority of cases.

Screening for pre-diabetes to predict future diabetes using various cut-off points for HbA(1c) and impaired fasting glucose: the Toranomon Hospital Health Management Center Study 4 (TOPICS 4)

AIM

To evaluate various screening criteria for pre-diabetes to identify which combination of impaired fasting glucose and elevated HbA(1c) values performs most effectively in predicting future diabetes in a large cohort of Japanese individuals.

METHODS

The study included 4670 men and 1571 women without diabetes (diabetes: fasting plasma glucose ≥ 7.0 mmol/l, HbA(1c) ≥ 48 mmol/mol (≥ 6.5%), or self-reported clinician-diagnosed diabetes). Pre-diabetes was diagnosed by a combination of impaired fasting glucose (fasting plasma glucose 5.6-6.9 mmol/l or 6.1-6.9 mmol/l) and elevated HbA(1c) [39-46 mmol/mol (5.7-6.4%) or 42-46 mmol/mol (6.0-6.4%)].

RESULTS

During a 5-year follow-up, 338 incident cases of diabetes occurred. The combination of HbA(1c) 39-46 mmol/mol (5.7-6.4%) and fasting plasma glucose 5.6-6.9 mmol/l yielded the highest sensitivity (86%) and generated a large population-attributable per cent risk (78%) for predicting development of diabetes. Among individuals classified as having pre-diabetes by any of the four combined criteria, 20.5-32.0% reverted to the normoglycaemic state as having neither elevated HbA(1c) nor impaired fasting glucose at the last follow-up examination. At 5.6 years after the baseline examination, however, pre-diabetic individuals who fulfilled both HbA(1c) 42-46 mmol/mol (6.0-6.4%) and fasting plasma glucose 6.1-6.9 mmol/l had a 100% cumulative risk of developing diabetes.

CONCLUSIONS

The combination of HbA(1c) 39-46 mmol/mol (5.7-6.4%) and fasting plasma glucose 5.6-6.9 mmol/l would have the best performance in reducing the likelihood of missing future cases of diabetes. Identifying pre-diabetic individuals who strictly fulfil HbA(1c) 42-46 mmol/mol (6.0-6.4%) and fasting plasma glucose 6.1-6.9 mmol/l would predict definite progression to diabetes.

Performance of HbA1c as an early diagnostic indicator of type 1 diabetes in children and youth

OBJECTIVE

The aim of this study was to evaluate HbA(1c) as an alternative criterion for impaired glucose tolerance (IGT) or type 1 diabetes (T1D) in high-risk subjects <21 years of age.

RESEARCH DESIGN AND METHODS

Subjects <21 years of age who participated in the prospective DPT-1, TEDDY, TRIGR, and Type 1 Diabetes TrialNet Natural History (TrialNet) studies and had an HbA(1c) within 90 days of an OGTT with a 2-h plasma glucose (2-hPG) measure were included. An OGTT of 140-199 mg/dL defined IGT, and an OGTT with 2-hPG ≥200 mg/dL or fasting plasma glucose ≥126 mg/dL defined diabetes. HbA(1c) ≥5.7% defined IGT, and HbA(1c) ≥ 6.5% defined diabetes. Receiver-operating characteristic curve analysis was used to assess diagnostic accuracy of HbA(1c) compared with OGTT.

RESULTS

There were 587 subjects from DPT-1, 884 from TrialNet, 91 from TEDDY, and 420 from TRIGR. As an indicator for IGT, HbA(1c) sensitivity was very low across the studies (8-42%), and specificity was variable (64-95%). With HbA(1c) ≥6.5% threshold used for T1D diagnosis, the sensitivity was very low and specificity was high (sensitivity and specificity: DPT-1 24 and 98%, TrialNet 28 and 99%, TEDDY 34 and 98%, and TRIGR 33 and 99%, respectively). The positive predictive value of HbA(1c) ≥6.5% for the development of T1D was variable (50-94%) across the four studies.

CONCLUSIONS

HbA(1c) ≥6.5% is a specific but not sensitive early indicator for T1D in high-risk subjects <21 years of age diagnosed by OGTT or asymptomatic hyperglycemia. Redefining the HbA(1c) threshold is recommended if used as an alternative criterion in diagnosing T1D.

Biomarkers in Type 2 diabetes: improving risk stratification with the PreDx ® Diabetes Risk Score

Type 2 diabetes is a chronic, debilitating and often deadly disease that has reached epidemic proportions. The onset of diabetes can be delayed or prevented in high-risk individuals by diet and lifestyle changes and medications, and hence a key element for addressing the diabetes epidemic is to identify those most at risk of developing diabetes so that preventative measures can be effectively focused. The PreDx(®) Diabetes Risk Score is a multimarker tool for assessing a patient's risk of developing diabetes within the next 5 years. Requiring a simple blood draw using standard sample collection and handling procedures, the PreDx Diabetes Risk Score is easily implemented in clinical practice and provides an assessment of diabetes risk that is superior to other measures, including fasting plasma glucose, glycated hemoglobin, measures of insulin resistance and other clinical measures. In this article, we provide an overview of the PreDx Diabetes Risk Score.

Alternative HbA1c cutoffs to identify high-risk adults for diabetes prevention: a cost-effectiveness perspective

BACKGROUND

New recommendations about the use of hemoglobin A1c (HbA1c) for diagnosing diabetes have stimulated a debate about the optimal HbA1c cutoff to identify prediabetes for preventive intervention.

PURPOSE

To assess the cost effectiveness associated with the alternative HbA1c cutoffs for identifying prediabetes.

METHODS

A Markov simulation model was used to examine the cost effectiveness associated with a progressive 0.1% decrease in the HbA1c cutoff from 6.4% to 5.5%. The target population was the U.S. nondiabetic population aged ≥18 years. The simulation sample was created using the data of nondiabetic American adults from the National Health and Nutritional Examination Survey (NHANES 1999-2006). People identified as having prediabetes were assumed to receive a preventive intervention, with effectiveness the same as that in the Diabetes Prevention Program study under a high-cost intervention (HCI) scenario and in the Promoting a Lifestyle of Activity and Nutrition for Working to Alter the Risk of Diabetes study under a low-cost intervention (LCI) scenario. The analysis was conducted for a lifetime horizon from a healthcare system perspective.

RESULTS

Lowering the HbA1c cutoff would increase the health benefits of the preventive interventions at higher costs. For the HCI, lowering the HbA1c cutoff from 6.0% to 5.9% and from 5.9% to 5.8% would result in $27,000 and $34,000 per QALY gained, respectively. Continuing to decrease the cutoff from 5.8% to 5.7%, from 5.7% to 5.6%, and from 5.6% to 5.5% would cost $45,000, $58,000, and $96,000 per QALY gained, respectively. For the LCI, lowering the HbA1c cutoff from 6.0% to 5.9% and from 5.9% to 5.8% would result in $24,000 and $27,000 per QALY gained, respectively. Continuing to lower the cutoff from 5.8% to 5.7%, 5.7% to 5.6%, and 5.6% to 5.5% would cost $34,000, $43,000 and $70,000 per QALY gained, respectively.

CONCLUSIONS

Lowering the HbA1c cutoff for prediabetes leads to less cost-effective preventive interventions. Assuming a conventional $50,000/QALY cost-effectiveness benchmark, the HbA1c cutoffs of 5.7% and higher were found to be cost effective. Lowering the cutoff from 5.7% to 5.6% also may be cost effective, however, if the costs of preventive interventions were to be lowered.

Association between sleep duration and haemoglobin A1c in young adults

BACKGROUND

Epidemiological and experimental evidence suggests that inadequate sleep can cause both obesity and impaired glucose tolerance. Short sleep duration in childhood appears to have a greater impact on the risk for adult obesity than adult sleep duration. The long-term effects of childhood sleep on glucose metabolism have not been investigated. The authors assessed the associations between childhood and adult sleep duration and adult glycosylated haemoglobin (HbA(1c)) levels.

METHODS

An unselected cohort of 1037 individuals, born in Dunedin, New Zealand, between 1972 and 1973. Parent reports of times in bed at ages 5, 7, 9 and 11 were used to estimate childhood sleep duration. Adult sleep duration was estimated from self-reported times in bed at age 32. HbA(1c) levels were measured at age 32. Pregnant women and participants with diabetes were excluded from the analyses.

RESULTS

Childhood sleep duration did not predict adult HbA(1c). However, less time spent in bed at age 32 was associated with higher levels of HbA(1c) (p=0.002) and an increased risk of prediabetes (p=0.015). The inverse association between adult sleep times and HbA(1c) was independent of body mass index, smoking, socioeconomic status, shift work and symptoms of obstructive sleep apnoea.

CONCLUSIONS

Short sleep duration is associated with higher levels of HbA(1c) and an increased risk of prediabetes in young adults. The findings suggest that inadequate sleep impairs glucose control in the short term and may increase the risk for long-term health problems.