Kidney Damage and Associated Risk Factors in the Rural Eastern Cape, South Africa: A Cross-Sectional Study

Background The colliding epidemic of infectious and non-communicable diseases in South Africa could potentially increase the prevalence of kidney disease. This study determines the prevalence of kidney damage and known risk factors in a rural community of the Eastern Cape province, South Africa. Methods This observational cross-sectional study was conducted in the outpatient department of the Mbekweni Community Health Centre in the Eastern Cape between May and July 2022. Relevant data on demography, medical history, anthropometry and blood pressure were obtained. The glomerular filtration rate was estimated using the Chronic Kidney Disease Epidemiology Collaboration Creatinine (CKD-EPI Creatinine ) equation and the re-expressed four-variable Modification of Diet in Renal Disease (MDRD) equation, without any adjustment for black ethnicity. Significant kidney damage was defined as low eGFR (<60mL/min per 1.73m 2 ) and/or the presence of proteinuria. We used the logistic regression model analysis to identify the independent risk factors for significant kidney damage. Results The mean (±standard deviation) age of the 389 participants was 52.3 (± 17.5) years. The prevalence of significant kidney damage was 17.2% (n=67), as estimated by the CKD-EPI Creatinine, with slight difference from the MDRD equation (17.7%; n=69), while the prevalence of proteinuria was 7.2%. Risk factors for significant kidney damage were older age (OR=0.94, 95% CI 0.91 - 0.96, p<0.001) and the presence of proteinuria (OR=0.98, 95% CI 0.97 - 0.99, p 0.002). Proteinuria was strongly associated with hypertension (OR=4.46, 95% CI 1.33 - 14.92, p<0.015) and elevated serum creatinine (OR=1.01, 95% CI 1 - 1.02, p=0.004). Conclusions: This study found a high prevalence of kidney damage (17.2%) and proteinuria (7.2%) in this rural community, largely attributed to advanced age and hypertension, respectively. Early detection of proteinuria and decreased renal function could lead to prompt preventative measures and management to delay the progression to end-stage kidney failure and mortality.