Beta cell function, insulin resistance and glycemic control in type 2 diabetes mellitus

Abstract

Diabetes Mellitus (DM) patients may be categorized into two major groups: type 1 - and type 2 diabetes. Beta cell failure and insulin resistance is the hall mark of type 2 diabetes. Knowledge on the pathophysiology of diabetes improves clinical management. There is scanty data on beta cell function and insulin resistance in type 2 diabetes patients in Uganda. This study investigated beta cell function, insulin resistance and glycaemic control in type 2 diabetes patients attending St. Francis Hospital, Nsambya, Kampala Study objective: To describe beta cell function, insulin resistance and glycemic control among type 2 DM patients at Nsambya hospital, Kampala Uganda. Methods: A cross sectional study was conducted among out – patients at Nsambya hospital, diagnosed with DM at ages above 30 years, on oral hypoglycemic agents and of less than 10 years DM duration. Venous blood samples were drawn and the patients’ fasting blood glucose, fasting serum C – peptide and HbA1c levels were determined. Their respective insulin resistance (HOMA2 IR), insulin sensitivity (HOMA2 %S) and beta cell function (HOMA2% B×HOMA2 %S) were estimated using the HOMA2 evaluation tool. Statistical analysis was done using SPSS version 20. Results: Eighty one study participants were selected from the type 2 DM Clinic at Nsambya hospital. The mean beta cell function was 0.397 + 0.052 (Standard Error of Mean (SEM)). The proportion of beta cell dysfunction (HOMA2% B×HOMA2 %S < 1.0) was 94.4 %. The mean Insulin Resistance was 3.3 + 0.4 (SEM). The proportion of insulin resistance (HOMA2 IR > 2.5) was 35.8 % (29/81). Twenty seven percent of study participants had severe insulin resistance (HOMA2 IR > 3.0). Sixty eight percent (55/81) of study participants had suboptimal glycemic control (HbA1c > 7.0 %). There were no correlations of statistical significance between participants’ baseline characteristics with beta cell function nor insulin resistance. Conclusions: Beta cell dysfunction was a more predominant factor (94.4%) than insulin resistance (35.8 %) among type 2 DM patients at Nsambya hospital. The proportion of suboptimal glycemic control was high (68%). There were no correlations between patients’ baseline characteristics with beta cell dysfunction nor insulin resistance. Recommendations: 1. It is recommended that case control and / or prospective cohort studies with larger type 2 DM patient numbers would provide a better understanding of the evolution of beta cell function and insulin resistance as a means of accounting for differences in individual physiology and the multi – factorial nature of dependence of glycemic control in type 2 DM.