Derivation & validation of glycosylated haemoglobin (HbA 1c ) cut-off value as a diagnostic test for type 2 diabetes in south Indian population.
TL;DR: HbA1c >6.3 per cent appears to be the optimal cut-off value for the diagnosis of type 2 diabetes applicable to the ethnic population of Rayalaseema area of Andhra Pradesh state in south India.
Abstract: Background & Objectives: Glycosylated haemoglobin (HbA 1c ) has been in use for more than a decade, as a diagnostic test for type 2 diabetes. Validity of HbA 1c needs to be established in the ethnic population in which it is intended to be used. The objective of this study was to derive and validate a HbA 1c cut-off value for the diagnosis of type 2 diabetes in the ethnic population of Rayalaseema area of south India. Methods: In this cross-sectional study, consecutive patients suspected to have type 2 diabetes underwent fasting plasma glucose (FPG) and 2 h post-load plasma glucose (2 h-PG) measurements after a 75 g glucose load and HbA 1c estimation. They were classified as having diabetes as per the American Diabetes Association criteria [(FPG ≥7 mmol/l (≥126 mg/dl) and/or 2 h-PG ≥11.1 mmol/l (≥200 mg/dl)]. In the training data set (n = 342), optimum cut-off value of HbA 1c for defining type 2 diabetes was derived by receiver-operator characteristic (ROC) curve method using oral glucose tolerance test results as gold standard. This cut-off was validated in a validation data set (n = 341). Results: On applying HbA 1c cut-off value of >6.3 per cent (45 mmol/mol) to the training data set,sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for diagnosing type 2 diabetes were calculated to be 90.6, 85.2, 80.8 and 93.0 per cent, respectively. When the same cut-off value was applied to the validation data set, sensitivity, specificity, PPV and NPV were 88.8 , 81.9, 74.0 and 92.7 per cent, respectively, although the latter were consistently smaller than the proportions for the training data set, the differences being not significant. Interpretation & conclusions: HbA 1c >6.3 per cent (45 mmol/mol) appears to be the optimal cut-off value for the diagnosis of type 2 diabetes applicable to the ethnic population of Rayalaseema area of Andhra Pradesh state in south India.
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TL;DR: HbA1c ≥6.5% is a convenient and reliable alternative to plasma glucose tests to diagnose diabetes among high-risk South Indians and 0.6% had 100% negative predictive value to exclude prediabetes/diabetes.
Abstract: Background: Glycosylated hemoglobin (HbA1c) has not been evaluated extensively for diabetes and prediabetes diagnosis and short-term variability of fasting plasma glucose (FPG), 2-h PG post-75 g glucose load (2 hPG) and HbA1c has not been studied among Indians. Objectives: The study aimed to compare the sensitivity of HbA1c, FPG and 2 hPG for diabetes and prediabetes diagnosis as per the American Diabetes Association criteria, assess short-term variability of three tests and determine optimal HbA1c cutoffs for diabetes and prediabetes diagnosis among high-risk south Indians. Methods: This diagnostic accuracy study, conducted at a tertiary care teaching hospital located in South India, enrolled 332 adults at high risk for diabetes and subjected them to testing (FPG, 2 hPG, and HbA1c) twice at 2–3 weeks interval. Sensitivity of three tests for diagnosing diabetes and prediabetes was determined based on the final diagnosis of normoglycemia/prediabetes/diabetes made with six test results for each participant. Optimal HbA1c cutoffs for diabetes and prediabetes were determined based on the final diagnosis of glycemic status made with four test results of FPG and 2 hPG. Results: FPG, 2 hPG, and HbA1c, at American Diabetes Association recommended values, had sensitivity of 84.4%, 97%, and 93.8% respectively for diabetes diagnosis. HbA1c had lowest short-term variability (CVw = 1.6%). Receiver operating characteristic curve plotted with mean (of two values) HbA1c for each participant showed optimal HbA1c cutoffs of 6.5% for diabetes (area under curve [AUC] =0.990, sensitivity = 95.8%, specificity = 96.2%, accuracy = 95.2%) and 5.9% for prediabetes (AUC = 0.893, sensitivity = 84.3%, specificity = 80%, accuracy = 75.6%) diagnosis respectively. HbA1c
11 citations
Cites background from "Derivation & validation of glycosyl..."
...HbA1c >6.3% was found to be optimal cutoff value for the diagnosis of type 2 diabetes in a study from Andhra Pradesh state in South India....
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...3% was found to be optimal cutoff value for the diagnosis of type 2 diabetes in a study from Andhra Pradesh state in South India.[27] A study from North India[6] found an optimal HbA1c cut-point of 6....
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TL;DR: It is believed that in selecting the criterion used to derive the most appropriate test cut-off value in the receiver operating characteristic (ROC) curve analysis, the author should also consider other important contributing factors.
Abstract: We read with interest the article of Mohan et al1 on determination of glycosylated haemoglobin (HbA1c) cut-off value for the diagnosis of type 2 diabetes in Rayalaseema area in Andhra Pradesh, Southern India1. They mention that various studies have reported different HbA1c cut-off values from ≥5.6 per cent (38 mmol/mol) to ≥7.0 per cent (53 mmol/mol) and that ‘age, ethnicity, genetic makeup, erythrocyte lifespan and erythrocyte environment’ are the most likely causes of the observed variance. We believe that in selecting the criterion used to derive the most appropriate test cut-off value in the receiver operating characteristic (ROC) curve analysis, we should also consider other important contributing factors2.
3 citations
TL;DR: To determine whether intermediate hyperglycaemia, defined by fasting plasma glucose and HbA1c criteria, is associated with mortality in a 10‐year cohort of people in a Latin American country, a cohort study is conducted.
Abstract: AIM To determine whether intermediate hyperglycaemia, defined by fasting plasma glucose and HbA1c criteria, is associated with mortality in a 10-year cohort of people in a Latin American country. METHODS Analysis of the PERU MIGRANT Study was conducted in three different population groups (rural, rural-to-urban migrant, and urban). The baseline assessment was conducted in 2007/2008, with follow-up assessment in 2018. The outcome was all-cause mortality, and the exposure was intermediate hyperglycaemia, using three definitions: (1) impaired fasting glucose, defined according to American Diabetes Association criteria [fasting plasma glucose 5.6-6.9 mmol/l (100-125 mg/dl)]; (2) intermediate hyperglycaemia defined according to American Diabetes Association criteria [HbA1c levels 39-46 mmol/mol (5.7-6.4%)]; and (3) intermediate hyperglycaemia defined according to the International Expert Committee criteria [HbA1c levels 42-46 mmol/mol (6.0-6.4%)]. Crude and adjusted hazard ratios and 95% CIs were estimated using Cox proportional hazard models. RESULTS At baseline, the mean (sd) age of the study population was 47.8 (11.9) years and 52.5% of the cohort were women. The study cohort was divided into population groups as follows: 207 people (20.0%) in the rural population group, 583 (59.7%) in the rural-to-urban migrant group and 198 (20.3%) in the urban population group. The prevalence of intermediate hyperglycaemia was: 6%, 12.9% and 38.5% according to the American Diabetes Association impaired fasting glucose definition, the International Expert Committee HbA1c -based definition and the American Diabetes Association HbA1c -based definition, respectively, and the mortality rate after 10 years was 63/976 (7%). Intermediate hyperglycaemia was associated with all-cause mortality using the HbA1c -based definitions in the crude models [hazard ratios 2.82 (95% CI 1.59-4.99) according to the American Diabetes Association and 2.92 (95% CI 1.62-5.28) according to the International Expert Committee], whereas American Diabetes Association-defined impaired fasting glucose was not [hazard ratio 0.84 (95% CI 0.26-2.68)]. In the adjusted model, however, only the American Diabetes Association HbA1c -based definition was associated with all-cause mortality [hazard ratio 1.91 (95% CI 1.03-3.53)], whereas the International Expert Committee HbA1c -based and American Diabetes Association impaired fasting glucose-based definitions were not [hazard ratios 1.42 (95% CI 0.75-2.68) and 1.09 (95% CI 0.33-3.63), respectively]. CONCLUSIONS Intermediate hyperglycaemia defined using the American Diabetes Association HbA1c criteria was associated with an elevated mortality rate after 10 years in a cohort from Peru. HbA1c appears to be a factor associated with mortality in this Peruvian population.
2 citations
TL;DR: In this paper , the effect of 2-only-daily-meals with exercise (2-OMEX) for its effect on HbA1c, oral hypoglycaemic agents (OHA) usage, body-weight among type-2-diabetes (T2DM) subjects, compared with conventional management was evaluated.
Abstract: Background: Rising prevalence and poor outcomes make the twin challenges of diabetes epidemiology. This study evaluates effect of 2-only-daily-meals with exercise (2-OMEX) for its effect on HbA1c, oral hypoglycaemic agents (OHA) usage, body-weight among type-2-diabetes (T2DM) subjects, compared with conventional management. Material and Methods: A quasi-experimental, multicentre study in 2-OMEX arm, and HbA1c by HPLC method. HbA1c and body-weight changes were analyzed by 'Difference in Difference' (DID) method. Meal frequency, exercise, energy intakes were based on recall. The required sample size was 20X2 for 1.1 difference in HbA1c with 95% CL and 80% power Results: Socio-demographic and risk profile of analysed and omitted subjects were similar. Studied arms were also similar in baseline features. The results in 2-OMEX and conventional arm are: complete records analyzed 201 and 120. Mean (sd) values as follows: observation days 234 and 236, age 52.03(8.84) and 52.45(9.48) years (P=0.6977), diabetes duration 4.6(3.05) and 4.9(2.97) years, BMI 27.28(5.27), 26.90(3.74) (P = 0.1859), baseline HbA1c gm% 7.46(1.52) and 7.55(1.58), end-line proportion of subjects attaining HbA1c ≤6.5gm% was 35.3% and 19.2% (P=0.002), bodyweight loss 2.57% and 1.26%. OHA count 1.6 (1.23) and 2.7(1.06), (P=0.0003). In 2-OMEX arm log-normal HbA1c declined significantly by 0.94 (95%CI: 1.60 to – 0.56, p=0.0333), weight loss difference 0.96 kg, and statistically not significant (P=0.595). Two subjects in 2-OMEX arm showed partial remission. Mean baseline Kcal intakes in 2-OMEX arm, were 1200.4(F) and 1437.3(M) were significantly higher than conventional arm (F) and 1430 (M) Conclusion: The 2-OMEX showed a sizeable and significant reduction in HbA1c and OHA use, in 7-months, with moderate intakes, compared to the conventional arm, possibly attributable to fewer insulin surges. More studies are required for its impact and pathways.
References
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TL;DR: The optimum HbA1c cutoff point for diabetes in the study population was lower than ADA criteria, and Hb a1c may not be used to identify Impaired glucose regulation, IGR.
25 citations
TL;DR: The results suggest that HbA1c ≥ 6.5% has reasonably good specificity for diagnosing diabetes in Chinese subjects, which is in concordance with the American Diabetes Association recommendations.
Abstract: 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.
25 citations
TL;DR: The study showed that HbA1c values of > or = 6.0% gave a reasonably high sensitivity and specificity for diagnosis using the WHO or ADA criteria, but wide inter-individual variations even in the normoglycaemic range make the test unsuitable for diagnostic purpose.
19 citations
01 Jan 2007
TL;DR: The glycation gap between the results of an intracellular (A1C) and an extracellular (fructosamine) protein target of glycation or an integrated measure of glycemic control supports the validity of the high glycator–low glycator hypothesis.
Abstract: glycemic control, glycated serum proteins measured as fructosamine, to overcome the limitations of blood glucose sampling frequency and time distribution. While we have been taught that A1C and glycated serum proteins are measures that reflect glycemic control over different time periods, when patients are at steady state—as they probably are most of the time—the temporal factors cancel out, and there can be an extraordinarily tight correlation within an individual (8). When looked at in this way, 23% of subjects had A1C1 percentage point higher and 17% had A1C 1 percentage point lower than the value predicted from simultaneously drawn glycated serum proteins. Results within individuals are fairly consistent over time. We referred to this as a glycation gap between the results of an intracellular (A1C) and an extracellular (fructosamine) protein target of glycation or an integrated measure of glycemic control. The within-subject inconsistency of two precise measures of glycemic control supports the validity of the high glycator–low glycator hypothesis, i.e., physiologic as opposed to technical causes for differences in A1C. We have shown the glycation gap to be linked to nephropathy status in a small population in which we did not detect an association with A1C. Others suggest that the remaining variation in A1C is relatively small (10) and technical in nature such that by improved standardization of the A1C assay, coupled with continuous glucose monitoring, one size should fit all. Indeed, the A1C, when measured accurately, is a close reflection of glycemia in the vast majority of otherwise normal patients. This school of thought has expressed skepticism of the high glycator–low glycator hypothesis and questions the need for this
18 citations
TL;DR: For high risk patients whose fasting glucose was more than 100 mg/dL, HbA1c criterion underestimated the prevalence of newly diagnosed diabetes compared to the 2003 ADA criteria, and showed moderate agreement.
Abstract: BACKGROUND Hemoglobin A1c (HbA1c) was adopted as a new standard criterion for diagnosing diabetes. We investigated the diagnostic utility of HbA1c by comparing the 2003 American Diabetes Association (ADA) diagnostic criteria of diabetes with HbA1c of 6.5%. Furthermore, the cut-off value for HbA1c was investigated using receiver operating characteristic curves. METHODS This study included 224 subjects without a history of diabetes that had a fasting plasma glucose level of above 100 mg/dL. The subjects had undergone a 75 g oral glucose tolerance test, and diabetes was defined as according to 2003 ADA criteria. RESULTS The prevalence of newly diagnosed diabetes was 58.2% by the 2003 ADA criteria, and 47.8% by HbA1c of 6.5%, which underestimated the prevalence of diabetes. Compared with the 2003 ADA criteria, the sensitivity and specificity of HbA1c of 6.5% were 73.5% and 89.1%, respectively. The kappa index of agreement between 2003 ADA and HbA1c criteria was 0.60. The cut-off point of HbA1c for diagnosing diabetes was 6.45% (sensitivity, 73.3%; specificity, 88.2%; area under the curve, 0.85). HbA1c was significantly associated with fasting glucose (r = 0.82, P < 0.01), postprandial glucose (r = 0.78, P < 0.01), and homeostasis model assessment of insulin resistance (r = 0.16, P < 0.05). CONCLUSION For high risk patients whose fasting glucose was more than 100 mg/dL, HbA1c criterion underestimated the prevalence of newly diagnosed diabetes compared to the 2003 ADA criteria, and showed moderate agreement. The cut-off value for HbA1c was 6.45%, which was similar to the recommended diagnostic criterion of HbA1c by the 2009 ADA.
18 citations