Pharmacotherapy for hypertension in the elderly

To quantify the long-term effects of antihypertensive drug therapy on morbidity and mortality in the elderly. To characterize co morbid risk profiles of trial participants.

Electronic search of WHO-ISH Collaboration register (August 1997), The Cochrane Library (1997; Issue 1), MEDLINE (1966 to April 1997) and two Japanese databases (1973-1995); references from reviews, trials and 10 previously published meta-analyses; and experts.

Randomized controlled trials of at least one year duration in hypertensive elders (at least 60 years old) assessing antihypertensive drug therapy and providing morbidity and mortality data.

At least two independent reviewers abstracted data on morbidity and mortality results and trial characteristics. The following outcomes were assessed: total mortality; coronary heart disease (CHD) mortality; combined CHD morbidity and mortality; cerebrovascular mortality; combined cerebrovascular morbidity and mortality; cardiovascular mortality; combined cardiovascular morbidity and mortality; and drop outs due to side effects of treatment.

Fifteen trials including 21,908 elderly subjects were identified. The average prevalence of cardiovascular risk factors, cardiovascular disease, and competing co morbid diseases was lower among trial participants than the general population of hypertensive elderly persons. Most subjects were 60 to 80 years old. Most trials were conducted in Western, industrialized countries and evaluated diuretic and beta-blocker therapies. Event rates per 1000 participants over approximately 5 years indicated that antihypertensive drug therapy was beneficial. Cardiovascular morbidity and mortality was reduced from 177 to 126 events (95% CI of the difference 31 to 73). Cardiovascular mortality was reduced from 69 to 50 deaths (95% CI of the difference 9 to 31). Total mortality was reduced from 129 to 111 deaths (95% CI of difference 4 to 28). The data from the three trials restricted to persons with isolated systolic hypertension indicated a significant benefit: cardiovascular morbidity and mortality over approximately 5 years was reduced from 157 to 104 events per 1000 participants (95% CI of the difference 12 to 89). Numbers of participants who dropped out of trials secondary to adverse drug effects were often not reported. The four trials that did report this data showed a wide variation in drop out rates ranging from no significant differences between treatment and control groups to as many as one out of four patients dropping out due to side effects of treatment.

Randomized controlled trials establish that treating healthy older persons with hypertension is highly efficacious. Benefits of treatment with low dose diuretics or beta-blockers are clear for persons in their 60s to 70s with either diastolic or systolic hypertension. Differential treatment effects based on patient risk factors, pre-existing cardiovascular disease and competing co-morbidities could not be established from the published trial data.