Correlations between Glycated Hemoglobin (HbA1c) and Oral Glucose Tolerance test, OGTT (and Some Cardiovascular Risk Factors) in a Cohort Population of Patients at the University of Port Harcourt Teaching Hospital (UPTH), Niger Delta Region of Nigeria

Abstract

Background: Diabetes mellitus (DM) is increasing in prevalence globally and in Nigeria today. Fasting blood glucose and oral glucose tolerance test (OGTT) have been the traditional gold standard tests for diagnosis of DM until recently when glycated hemoglobin (HbA1c) is being used. Is there a correlation between the two? Objectives: The aim of this study was to determine the level of correlation between HbA1c and OGTT and some cardiovascular risk factors in a certain population in UPTH, Nigeria. Materials and Methods: This was a cross-sectional study involving 400 consecutively attending patients at the medical and general outpatient clinics of UPTH. Results: The HbA1C had a strong positive correlation with the 2 h post-glucose load of the OGTT (r = 0.652, P < 0.001). The HbA1c also had a positive correlation with the body mass index, waist circumference, age, total cholesterol (TC), triglyceride levels, and low-density lipoprotein cholesterol levels, but it was most positively correlated with the TC (r = 0.582, P < 0.001). It was, however, negatively correlated with the high-density lipoprotein cholesterol (r = −0.166, P = 0.001).Conclusion: Glycated HbA1c had a positive correlation with OGTT, and most of the cardiovascular risk factors of DM studied.