The incidence of treated hypertension and time trends in the use of antihypertensive medications in older adults
In the Cardiovascular Health Study (CHS), a cohort study of adults aged 65 or older, annual examinations included blood pressure measurements and an assessment of medication use. In 1989-90, 5201 subjects were recruited, and in 1992-3, another 687 African Americans joined the cohort. At baseline, 40% of the cohort had treated hypertension. During follow-up, 1091 started antihypertensive treatment, and 639 stopped. By 1997, 55% of the cohort had treated hypertension. Between baseline and the 1996-7 exam, the annual incidence of treated hypertension increased from 5.5% up to 8.3% as the cohort aged. In multivariate analysis, high levels of weight, systolic and diastolic blood pressure, non-white race, female sex, target organ disease, non-smoking, and a family history of CHD were all associated with incident treated hypertension. The adjusted incidence was higher in African Americans than in whites (OR = 1.32; 95% CI = 1.04-1.67). Among treated hypertensive participants, about 5% stopped antihypertensive treatment each year; and stopping was associated with older age, the use of fewer medications, and lower levels of systolic blood pressure. Between 1989 and 1997, among subjects free of coronary disease, the use of thiazide diuretics decreased from 60% to 40%, and β-blockers from 26% to 21%. During the same period, the use of ACE inhibitors increased steadily from 17% to 31%; α-blockers from 6% to 9%; and calcium channel blockers increased from 14% to 35% in 1995 and thereafter remained stable. A similar pattern of trends was apparent in subjects with coronary disease: for instance, thiazide diuretic use declined from 36% to 20% in subjects with coronary disease. Even though clinical trials published in the early 1990s have documented the importance of low-dose diuretic therapy for preventing the cardiovascular complications of untreated high blood pressure in older adults, the use of proven, effective, and inexpensive antihypertensive therapies declined between 1989 and 1997.