Prevalence and Risk Factors for Type 2 Diabetes Complications and Comorbidity in Sub-Saharan Africans

Background: Context-specific evidence of the spectrum of type 2 diabetes (T2D) burden is essential for setting priorities and designing interventions to reduce T2D morbidity and mortality. However, there are currently limited data on the burden of T2D complications and comorbidity in sub-Saharan Africa (SSA). Using a study of ~6,000 participants, we aimed to estimate the burden and risk factors for T2D complications and comorbidity in sub-Saharan Africans.   Methods: Participants (2784 T2D, 3209 controls) were African men and women aged 18 years or older, enrolled from major academic medical centres and surrounding communities in Ghana, Nigeria and Kenya. T2D was defined according to the American Diabetes Association criteria. T2D complications and comorbidities evaluated included cardiometabolic, ocular, neurological and renal characteristics. Logistic regression models were used to identify risk factors and to adjust estimates of risk and prevalence for covariates.   Results: T2D participants had a mean age of 56 [SD 11] years and a median duration of T2D of 5 (interquartile range 2-10) years. Among the T2D participants, notable associated complications/comorbidities included hypertension with a prevalence of 71% (95% CI 69-73), obesity 27% (25-29) and hyperlipidemia 34% (32-36). Diabetic retinopathy was found in 15% (13-17) and cataracts in 32% (30-35). About 13% (12-15) had impaired renal function as assessed by eGFR, representing 1 in 8 participants. Erectile dysfunction was a complication in 35% (32-38) of men. Age, duration of T2D and body mass index were significant risk factors for most complications/comorbidities. There was significant heterogeneity between sites in prevalence of most complications/comorbidities after adjusting for covariates. Population-attributable fraction ranged between 6 and 64 percent for most comorbidities. Conclusion: The burden of T2D complications and comorbidity is substantial among sub-Saharan Africans. Interventions to reduce T2D morbidity and mortality in SSA need to prioritise early detection, the maintenance of healthy blood pressure, weight and lipid levels, as well as strengthen health care system capacities to provide treatment and care for neurological and ophthalmological complications of T2D.   Funding Statement: The study was supported in part by the Intramural Research Program of the National Institutes of Health in the Center for Research on Genomics and Global Health (CRGGH). The CRGGH is supported by the National Human Genome Research Institute (NHGRI), the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), the Center for Information Technology, and the Office of the Director at the National Institutes of Health (1ZIAHG200362). Support for participant recruitment and initial genetic studies of the AADM study was provided by NIH grant No. 3T37TW00041-03S2 from the Office of Research on Minority Health. Declaration of Interests: The authors declare no competing interests. Ethics Approval Statement: The study received ethical approval from the Institutional Review Board at each study site, Howard University and the United States National Institutes of Health.