Introduction: In South Africa a cluster of cardiovascular diseases accounts for 17% of all deaths. It is also predicted that South Africa will face an epidemic of chronic kidney disease due to obesity, type 2 diabetes and hypertension. It is important to estimate the burden of underlying cardiovascular and renal disease in South Africa.
Objectives: The primary objective of the study was to establish the prevalence of left ventricular hypertrophy by ECG criteria, and micro- and macroalbuminuria in mild, moderate and severe hypertensive groups. The secondary objective was to establish the prevalence of left ventricular hypertrophy and micro- and macroalbuminuria in hypertensive patients with underlying type 2 diabetes.
Methods: Patients > or = 35 years with essential hypertension with or without type 2 diabetes were recruited from 100 general practices throughout South Africa. BP, weight, height, waist circumference and urinary albumin/creatinine ratio were measured, and an ECG was performed. The Sokolow-Lyon and Cornell criteria were used for estimation of left ventricular hypertrophy. An overall prevalence rate was determined using weights from the severity category distribution inside the study population.
Results: One thousand and ninety-one patients were available for analysis. There were 530 (48.5%) males and 561 (51.5%) females, 691 (63.3%) whites, 162 (14.8%) blacks, 150 (13.7%) Asians and 88 (8.1%) Coloureds. Of the patients, 10.9% had newly diagnosed hypertension, 20% had type 2 diabetes, and 38.1% mild, 32.1% moderate and 30.6% severe hypertension. The prevalence of left ventricular hypertrophy in the sample weighted to the hypertensive population over the age of 35 years with access to medical aids was 18.9%. Relative to white ethnicity, black ethnicity (OR 2, p = 0.03), and relative to mild hypertension, moderate (OR 2.2, p = 0.05) and severe hypertension (OR 4.9, p < 0.0001) were independent predictors of left ventricular hypertrophy. The overall prevalence of micro- and macroalbuminuria in the weighted sample was 21.3 and 4.1%, respectively. In the diabetics the prevalence of microalbuminuria was 32.3% and macroalbuminuria 10.4%, respectively. The independent predictors of microalbuminuria or worse were severe hypertension (OR 2.9, p < 0.0001), type 2 diabetes (OR 2.5, p < 0.002), and Asian ethnic group (OR 2, p = 0.02).
Conclusions: The study, based on a convenience sample of hypertensives from private practices in South Africa showed that the prevalence of left ventricular hypertrophy and microalbuminuria or worse was 18.9 and 25.4%, respectively.