Risk factors of poor control of HBA1c and diabetic retinopathy: Paradox with insulin therapy and high values of HDL in African diabetic patients

Abstract

Objective: To determine the risk factors of poor control of glycated haemoglobin and diabetic retinopathy. The agreement between poor control of glycated haemoglobin (HbA1c) >7% and poor control of glycemia ≥ 126 mg/dL to classify diabetic retinopathy was also assessed. Design, settings and methods: The study was a cross-sectional survey carried out on 300 African diabetic patients admitted to Lomo Medical Center, Kinshasa, Congo, between July 2005 and December 2007. Patients (150 type 1 and 151 type 2) were interviewed and underwent a complete medical assessment. HbA1c levels, anthropometry, blood pressure components, lipid profile, type of diabetes, severity and complications were determined for each patient. All patients were examined for evidence and severity of diabetic retinopathy by an ophthalmologist. Results: The rates of arterial hypertension, uncontrolled hypertension, poor control of HbA1c, poor control of glycemia, higher pulse pressure and diabetic retinopathy were 73.3%, 81.8%, 68%, 57%, 47.7% and 33.3%, respectively. Type 1 diabetes, diabetes duration ≥ 4 years, female sex, underweight, diabetic retinopathy, diabetic nephropathy, elevated total cholesterol and higher levels of HDL-cholesterol were significantly associated with poor control of HbA1c. There was a poor agreement of 52% and kappa statistic of 0.19 (p<0.0001) between poor control of HbA1c and poor glycemic control to classify diabetic retinopathy. In all diabetic patients, aged ≥60 years, female sex, diabetes duration ≥4 years, type 1 diabetes, higher pulse pressure, underweight, poor control of HbA1c, smoking, stroke, diabetic nephropathy and low HDL-cholesterol are significantly associated with the presence and the severity of diabetic retinopathy. However, in 87 diabetic patients with a history of intravenously administered insulin, duration diabetes ≥ 4 years and good control of HbA1c <7% are significantly associated with the presence of diabetic retinopathy. There was a J-shaped relationship between poor control of glycemia ≥126mg/dL and the severity of non proliferative diabetic retinopathy. Conclusion: Urgent and efficient diabetes care and diabetes monitoring are needed in sub-Saharan Africa.