Paraguayan National Blood Pressure Study: prevalence of hypertension in the general population.

Stroke and cardiovascular disease are major causes of death in Paraguay but no information is available on the distribution of blood pressure (BP) and the extent of hypertension in the general population. The aim of this study, which was the first comprehensive national survey in a country in South America, was to determine the prevalence of hypertension to ascertain the need for a national programme for the control of high BP. The study design was a cross-sectional survey. A multi-stage sampling process was used to identify areas within districts covering the five main regions of the country. Alternate houses were visited by eight survey teams within these areas; 9880 adults aged 18-74 years answered a questionnaire and had measurements of height, weight and BP (twice) according to a standard protocol. Using a modified WHO definition of hypertension, 39.1% of women and 26.8% of men had raised BP (mild, moderate or severe hypertension). More women than men had borderline hypertension (17.5% vs 8.3%) and mild hypertension (32.8% vs 20.8%), whereas about 6% of both sexes had moderate or severe hypertension. Prevalence increased markedly with age, such that more than one quarter of the sample > 60 years of age had moderate or severe hypertension. Both systolic and diastolic pressure showed a consistent increase with body mass index (P < or = 0.001). Almost half the subjects with measured moderate or severe hypertension were unaware that they had raised BP. Hypertension is a major health problem in Paraguay such that a national programme of detection and treatment may be warranted.