Alternative indices of glucose homeostasis as biochemical diagnostic tests for abnormal glucose tolerance in an African setting.

Accurate diabetes diagnosis is important in Africa, where rates are increasing, and the disease largely undiagnosed. The cumbersome oral glucose tolerance test (OGTT) remains the reference standard, while alternative diagnostic methods are not yet established in Africans. We assessed the ability of fasting plasma glucose (FPG), HbA1c and fructosamine, to diagnose OGTT-based abnormal glucose tolerance in mixed-ancestry South Africans. Mixed-ancestry adults, residing in Cape Town were examined between February and November 2015. OGTT values were used to classify glucose tolerance status as: screen-detected diabetes, prediabetes, dysglycaemia (combination of diabetes and prediabetes) and normal glucose tolerance. Of the 793 participants included, 65 (8.2%) had screen-detected diabetes, 157 (19.8%) prediabetes and 571 (72.0%) normal glucose tolerance. Correlations of FPG and 2-h glucose with HbA1c (r=0.51 and 0.52) were higher than those with fructosamine (0.34 and 0.30), both p<0.0001. The highest c-statistic for the prediction of abnormal glucose tolerance was recorded with 2-h glucose [c-statistic=0.997 (screen-detected diabetes), 0.979 (prediabetes) and 0.984 (dysglycaemia)] and the lowest with fructosamine (0.865, 0.596 and 0.677). At recommended or data-specific optimal cut-offs, no combination of FPG, HbA1c and fructosamine did better than 2-h glucose, while FPG was better than HbA1c and fructosamine on a range of performance measures. Abnormal glucose tolerance in this population is overwhelmingly expressed through 2-h glucose's abnormalities; and no combination of FPG, HbA1c and fructosamine was effective at accurately discriminating OGTT-defined abnormal glucose tolerance. Tested non-glucose based strategies are unreliable alternatives to OGTT for dysglycaemia diagnosis in this population.

Kengne AP ，Erasmus RT ，Levitt NS ，Matsha TE ... -  《-》

Combined use of a fasting plasma glucose concentration and HbA1c or fructosamine predicts the likelihood of having diabetes in high-risk subjects.

Ko GT ，Chan JC ，Yeung VT ，Chow CC ，Tsang LW ，Li JK ，So WY ，Wai HP ，Cockram CS ... -  《DIABETES CARE》

HbA1c and the diagnosis of diabetes and prediabetes in a middle-aged and elderly Han population from northwest China (HbA1c).

To identify the optimal threshold of HbA1c and to evaluate the predictive performance of HbA1c levels in diagnosing diabetes and prediabetes in a middle-aged and elderly Han Chinese population from northwest China. In all, 3354 participants aged ≥ 40 years with no history of diabetes from northwest China were enrolled in the present cross-sectional study. All subjects underwent a 75-g oral glucose tolerance test (OGTT), as well as HbA1c testing. HbA1c thresholds for diagnosing diabetes and prediabetes were identified by the highest sum of sensitivity and specificity of each cut-off point, and the receiver operating characteristic (ROC) curve was used to evaluate the diagnostic accuracy of the HbA1c threshold. The mean (± SD) age of the participants was 57 ± 8 years, and 70.75% were women. Based on results of the OGTT, 1347 (40.16%) subjects had impaired fasting glucose and/or impaired glucose tolerance, and 725 (21.62%) had diabetes. The area under the ROC curve for detecting undiagnosed diabetes and prediabetes by HbA1c levels was 0.810 (95% confidence interval [CI] 0.796-0.823) and 0.732 (95% CI 0.717-0.747), respectively. HbA1c threshold of 6.4% and 6.1% produced the highest sum of sensitivity (60.00% and 61.49%) and specificity (87.33% and 73.24%) for diagnosing diabetes and prediabetes, respectively. HbA1c is an effective and convenient method for diagnosing diabetes and prediabetes. HbA1c thresholds of 6.4% and 6.1% may be used as diagnostic criteria for diabetes and prediabetes, respectively, in the Han Chinese population living in northwest China.

Wu S ，Yi F ，Zhou C ，Zhang M ，Zhu Y ，Tuniyazi Y ，Huang L ，Huang X ，Wang F ，Bi Y ，Ning G ... -  《-》

A large proportion of prediabetes and diabetes goes undiagnosed when only fasting plasma glucose and/or HbA1c are measured in overweight or obese patients.

The purposes of the study were to determine the prevalence of unrecognized dysglycaemia in overweight (body mass index [BMI] 25-29.9 kg/m(2)) and obese (BMI ≥30 kg/m(2)) patients, to assess the extent to which measures of fasting plasma glucose (FPG) and/or HbA(1c), compared with oral glucose tolerance tests (OGTTs), misdiagnose dysglycaemia, and to determine the factors associated with an isolated abnormal post-OGTT glucose value. OGTT was performed and HbA(1c) was measured in 1283 inpatients with BMI scores ≥ 25 kg/m(2) and no history of dysglycaemia. Prediabetes was found in 257 (20.0%) subjects (197 with impaired glucose tolerance, 29 with impaired fasting glucose, 31 with both) and diabetes in 77 (6.0%), including 22 with FPG ≥ 7 mmol/L (WHO definition). The sensitivity of FPG >6 mmol/L, FPG >5.5 mmol/L, HbA(1c) ≥ 6% and the recommendations of the French National Agency of Accreditation and Evaluation in Health Care (ANAES) to identify patients with abnormal OGTTs was 29.9, 41.3, 36.8 and 15.6%, respectively. The factors that were independently associated with diabetes in obese women with FPG <7 mmol/L were age (per 10 years: OR 1.54 [1.00-2.11]; P=0.049) and FPG (OR 6.1 [1.4-30.0]; P=0.014), whereas age (OR 1.26 [1.09-1.44]; P<0.01) and waist circumference (per 10 cm: OR 1.17 [1.01-1.33]; P<0.05) were independently associated with dysglycaemia in obese women with FPG <6.1 mmol/L. In overweight and obese patients: dysglycaemia is commonly seen; FPG alone, compared with OGTT, failed to diagnose 70% of dysglycaemia cases; FPG >5.5 mmol/L and HbA(1c) ≥ 6.0% are not necessarily substitutes for OGTT; and older age and larger waist circumference should be used to select those obese women with normal FPG who might further benefit from OGTTs to diagnose dysglycaemia.

Cosson E ，Hamo-Tchatchouang E ，Banu I ，Nguyen MT ，Chiheb S ，Ba H ，Valensi P ... -  《-》

[Diagnostic value of fasting glucose, fructosamine, and glycated haemoglobin HbA(1c) with regard to ADA 1997 and who 1998 criteria for detecting diabetes and other glucose tolerance abnormalities].

Gołembiewska E 《-》