ABSTRACT
Objectives: To determine median HbA1c level in patients screened for DM and compare the diagnostic accuracy of HbA1c with the currently recommended ADA cut off, using 2 hours [h] plasma glucose [2-h PG] post 75 grams oral glucose tolerance test [OGTT] as gold standard
Study Design: Cross sectional study
Place and Duration of Study: Aga Khan University Hospital Karachi, from Jul 2014 to Nov 2015
Patients and Methods: Consecutive subjects screened by OGTT for diabetes mellitus [DM] were included. Blood sample for plasma glucose and HbA1c were analyzed on ADVIA 1800
Results: Total 146 subjects were included with median age 45 [IQR 54.2-35] years; 53 percent [n=77] being females. Median HbA1c of the study subjects was 6 percent [IQR 6.6-5.6]. Positive correlation was observed between age and HbA1c [5.7 percent [IQR 6.2-5.3] <40 y, 6.2 percent [IQR 6.8-5.8] in >40 y subjects; r 0.34, p=0.000]. Males had higher HbA1c than females [6.1 percent [IQR 6.8-5.7] years. 5.9 percent [IQR 6.4-5.4]; r 0.17, p=0.036]. HbA1c levels were significantly different amongst the different ethnic groups residing in Pakistan [p-value<0.03]. HbA1c was positively correlated with FPG [r=0.59, p-value<0.001] and 2-h PG [r=0.56, p-value<0.001]. Sensitivity, specificity, PPV, NPV for HbA1c at cutoff of 6.5 percent in diagnosing diabetes mellitus [DM] were 70 percent, 89 percent, 72 percent and 80 percent respectively
Conclusion: High median HbA1c levels is noted in our subjects. At cut off level of HbA1c >/=6.5 percent, 70 percent of subjects with DM were diagnosed using ADA criteria of 2-h PG for diabetes as gold standard. Ethnic differences were also observed in levels of HbA1c. There is a need to define cut off for our population