A comparative study of fasting, postprandial blood glucose and glycated hemoglobin for diagnosing diabetes mellitus in staff members of MMIMSR, Mullana, Ambala

Abstract

Introduction: For decades, the diagnosis of diabetes mellitus was based on blood glucose criteria, either the fasting blood glucose (FBG) or a 2-h value in the 75-g oral glucose tolerance test. In 2009, an International Expert Committee that included representatives of the American Diabetes Association (ADA), International Diabetes Federation and European Association for the Study of Diabetes recommended the use of the HbA1c test to diagnose diabetes with a threshold of ≥6.5% and this criterion was finally adopted by ADA in 2010. Hence, the study was undertaken to evaluate the predictive efficacy of glycated hemoglobin as a diagnostic tool for diabetes mellitus and to identify individuals at risk of developing diabetes mellitus using Indian Diabetes Risk Score (IDRS). Materials and Methods: This cross-sectional study was conducted on the staff members of the Maharishi Markandeshwar Institute of Medical Science and Research, Mullana, Ambala, Haryana, India. Out of the total 800 staff members, 200 staff members were included in the study (88 faculty members, 37 staff nurses, 12 laboratory technicians, 25 clerical staff, 38 class IV) selected by systemic random sampling. Every fifth member on the list was included in the sample. After obtaining the data, it was coded and analyzed using multivariate logistic regression analysis. Receiver operating characteristics curve analysis was used to predict the sensitivity, specificity, positivity, negativity and overall accuracy of a diagnostic test. A two-tailed test P < 0.05 was considered as statistically significant. Data was analyzed using SPSS 20 (IBM, Chicago, USA). Results: Out of 200 subjects, 19.5% were labeled diabetic using FBG, 23% by postprandial blood glucose (PPBG) and 38.5% by using glycated hemoglobin according to ADA guidelines. A total of 62% had high-risk score out of which majority belonged to group-I (faculty) followed by group-II (nursing staff) and group-IV (clerical staff). With the advancement of age in each gender, IDRS also increased significantly. FBG, PPBG and glycated hemoglobin had sensitivity of 51.1%, 50%, 82.2%; specificity of 89.6%, 89.7%, 74.8%; positive predictive value of 58.9%, 48.8%, 48.6%; and negative predictive value of 86.3%, 85.8%, 93.5%, respectively. FBG and PPBG were better correlated with glycated hemoglobin in males when compared to females. Correlation coefficient between FBG and glycated hemoglobin was stronger than PPBG and glycated hemoglobin. IDRS value ≥60 had optimum sensitivity of 65% and specificity 62.5% for determining diabetes. Conclusion: Combination of FBG and glycated hemoglobin as biochemical parameters for diagnosing diabetes mellitus was better when compared to FBG and PPBG so both can be taken as screening/diagnosing parameters. Glycated hemoglobin may be a useful measure for diagnosing diabetes and supports a possible cut-off point ≥6.5% that is in line with current recommendations.