Trends in the prevalence, awareness, treatment, and control of hypertension in the adult us population: Data from the health examination surveys, 1960 to 1991

The objective of this study was to describe secular trends in the distribution of blood pressure and prevalence of hypertension in US adults and changes in rates of awareness, treatment, and control of hypertension. The study design comprised nationally representative cross-sectional surveys with both an in-person interview and a medical examination that included blood pressure measurement. Between 6530 and 13 645 adults, aged 18 through 74 years, were examined in each of four separate national surveys during 1960-1962, 1971-1974, 1976-1980, and 1988-1991. Protocols for blood pressure measurement varied significantly across the surveys and are presented in detail. Between the first (1971-1974) and second (1976-1980) National Health and Nutrition Examination Surveys (NHANES I and NHANES II, respectively), age-adjusted prevalence of hypertension at ≥160/95 mm Hg remained stable at approximately 20%. In NHANES III (1988-1991), it was 14.2%. Age-adjusted prevalence at ≥140/90 mm Hg peaked at 36.3% in NHANES I and declined to 20.4% in NHANES III. Age-specific prevalence rates have decreased for every age-sex-race subgroup except for black men aged 50 and older. Age-adjusted mean systolic pressures declined progressively from 131 mm Hg at the NHANES I examination to 119 mm Hg at the NHANES III examination. The mean systolic and diastolic pressures of every sex-race subgroup declined between NHANES II and III (3 to 6 mm Hg systolic, 6 to 9 mm Hg diastolic). During the interval between NHANES II and III, the threshold for defining hypertension was changed from 160/95 to 140/90 mm Hg. Hypertension awareness has increased substantially at both thresholds, to 89% and 73% for 160/1995 and 140/90 mm Hg, respectively. Compared with only 16% of all people with hypertension being <160/95 mm Hg in 1960-1962 and 1971-1974, 64% of all people with hypertension now have it controlled to below the 160/95 mm Hg threshold but only 29% to below 140/90 mm Hg. For people with treated hypertension, the rate of control (<140/90 mm Hg) ranges from 47% of black men to 60% of white women. Hypertension prevalence in the United States has declined progressively since 1971, and the distributions of systolic and diastolic pressures have shifted downward during the approximately 30-year period between 1960-1962 and 1988-1991. Variation in blood pressure measurement techniques may explain some of the decline in prevalence and the downward shift in distribution. Hypertension awareness, treatment, and control also have improved tremendously during the same period, accounting for much of the shift at the upper end of the distribution. Despite these favorable trends, many people with hypertension are unaware of their condition, and many more are untreated or inadequately treated.