ABSTRACT
Objective: To determine the mean hemoglobin HbA1C levels of disease-free adults in a local population and its optimum cutoff for the diagnosis of diabetes
Study Design: Cross-sectional study
Place and Duration of Study: Department of Chemical Pathology and Endocrinology, Armed Forces Institute of Pathology, Rawalpindi, from January to September 2015
Methodology: Healthy subjects aged 18 years and above of either gender were recruited from local population. Pregnant ladies and individuals with known diabetes, chronic kidney disease, chronic liver disease, congestive cardiac failure, anemia, hemoglobinopathies, mental illness and individuals on glucocorticoid therapy were excluded. Fasting plasma glucose [FPG] or 2-hour plasma glucose [2-h PG] was analyzed using hexokinase methodology and glycated hemoglobin [Hb A1C] was also analyzed using turbidimetric inhibition immunoassay technique. Receiver operating characteristic [ROC] curves were plotted. Differences among the groups were tested by one-way ANOVA, and p <0.05 was considered statistically significant
Results: Among 558 subjects, 88.8% [496] were normoglycaemic [NG], 5.7% [32] were with impaired glucose fasting [IFG], and 5.4% [30] were diagnosed with diabetes mellitus [DM]. A1C was 5.00 +/-0.44% in NG and 6.28 +/-1.16% in diabetics. FPG in NG was 4.55 +/-0.95 mmol/L and in diabetics was 8.28 +/-1.78 mmol/L. The optimal HbA1C cutoff value for diagnosis of DM was at 6.05% [AUC 0.827 95% CI 0.732 to 0.923, p ²0.05 with its sensitivity of 53.3% and specificity of 98.5%. However, HbA1C showed suboptimal sensitivity and specificity for prediabetes
Conclusion: The mean HbAIC and cutoff point for diabetes in the study population is 5.07 +/-0.58% and 6.05%, respectively [AUC 0.827, 95% CI: 0.732 to 0.923, p<0.001] with 53.3% sensitivity and 98.5% specificity