Trends in the prevalence, awareness, treatment and control of hypertension: the WHO MONICA Project

OBJECTIVE: To describe the secular changes in the prevalence, awareness, treatment and control of hypertension. DESIGN: Two independent cross-sectional population surveys using standardized methods conducted between the early 1980s and mid-1990s. SETTING: Twenty-four geographically defined populations of the WHO MONICA Project. PARTICIPANTS: Randomly selected men and women aged 35-64 years. The total number of participants was 69 907. MAIN OUTCOME MEASURES: Two definitions of hypertension were used: 160/95 mmHg or above and 140/90 mmHg or above for systolic or diastolic blood pressure. Subjects on antihypertensive drug treatment were considered to be hypertensive regardless of their blood pressure. Treated subjects whose measured blood pressure level was less than 160/95 or 140/90 mmHg according to the two definitions, respectively, were considered to be adequately treated. RESULTS: The age-adjusted prevalence of hypertension decreased in most and increased in only a few populations. For both definitions of hypertension, the proportion of hypertensive subjects who were aware of their condition increased in three-quarters of the male populations and in two-thirds of the female populations. Furthermore, the proportion of hypertensive individuals on antihypertensive drug treatment increased in three-quarters of the populations. In the final survey, hypertension tended to be better treated and controlled in women than in men. Nevertheless, a large proportion of patients receiving antihypertensive drug therapy still had inadequately controlled blood pressure levels. CONCLUSION: Although awareness and treatment of hypertension according to the data obtained during the late 1980s to the mid-1990s increased in several populations, the effectiveness of antihypertensive treatment showed the continuing need for improvements.