The prevalence of microalbuminuria and ECG left ventricular hypertrophy in hypertensive patients in private practices in South Africa.
BACKGROUND
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.


OBJECTIVE
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.
Rayner
B
B
Division of Hypertension, University of Cape Town, Cape Town, South Africa.
Becker
P
P
D000328:Adult; D000419:Albuminuria / Q000453:epidemiology* / Q000503:physiopathology*; D004562:Electrocardiography; D005260:Female; D006801:Humans; D006973:Hypertension / Q000453:epidemiology* / Q000503:physiopathology*; D017379:Hypertrophy, Left Ventricular / Q000453:epidemiology* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011331:Private Practice; D013019:South Africa / Q000453:epidemiology