[Prevalence of systemic arterial hypertension and associated risk factors in the Porto Alegre metropolitan area. Populational-based study].

Purpose: To evaluate the contemporaneous prevalence of hypertension in Porto Alegre, RS, and its association with biological, socioeconomic and environmental factors.

Methods: It was done an observational and analytical study with a cross-sectional design, of a representative sample of the adults of the urban region. The study was planned with a power to describe the main estimates with 0.5% confidence limits of +/- 2%. One thousand and ninety one individuals, selected at random in conglomerates and in a multiple stage process, were interviewed. The data were obtained in the domiciles through standardized questionnaires and physical examination.

Results: The prevalence of hypertension, defined by blood pressure (BP) > or = 160/95 mmHg, was 12.6% (CI = 10.6 to 14.6). Considering as hypertensives the individuals with BP < 160/95 mmHg under drug treatment, the prevalence increased to 19.2% (CI = 16.9 to 21.5). The corresponding figures for the 140/90 mmHg criteria were 25.8% (CI = 23.2 to 28.4) and 29.8% (CI = 27.1 to 32.5). Among those using anti-hypertensive drugs (11%), 58.9 had BP < 160/95 mmHg and 35.5% < 140/90 mmHg; 57.7% of the hypertensives (160/95 criteria) were aware of diagnosis; 28% had body mass index above 27kg/m2, 15.5% consumed more than 30g per day of ethanol, 35.1% were smokers, and 17.8% ex-smokers. The prevalence increased with age and was higher in individuals with obesity, strong family history of hypertension, low education and in those which abused from alcoholic beverages. In a logistic regression model, these putative risk factors showed to be independent of others.

Conclusion: The contemporaneous prevalence of hypertension in Porto Alegre demonstrates that the prevalence rates have not decreased in the last 15 years. It was also shown an inadequate BP control in almost 50% of those under drug treatment, and finally, the association of hypertension with well-known risk factors.