An Alternate Road

Effectiveness and safety of beta blockers in the management of hypertension in older adults: a systematic review to help reduce inappropriate prescribing

BACKGROUND

The benefit from a blood pressure lowering therapy with beta blockers may not outweigh its risks, especially in older populations. The aim of this study was to look for evidence on risks and benefits of beta blockers in older adults and to use this evidence to develop recommendations for the electronic decision support tool of the PRIMA-eDS project.

METHODS

Systematic review of the literature using a stage approach with searches for systematic reviews and meta-analyses first, and individual studies only if the previous searches are inconclusive. The target population were older adults (≥65 years old) with hypertension. We included studies reporting on the effectiveness and/or safety of beta blockers on clinically relevant endpoints (e.g. mortality, cardiovascular events, and stroke) in the management of hypertension. The recommendations were developed according to the GRADE methodology.

RESULTS

Fifteen studies were included, comprising one meta-analysis, four randomized controlled trials, six secondary analyses of randomized controlled trials and four observational studies. Seven studies involved only older adults and eight studies reported subgroup analyses by age. With regard to a composite endpoint (death, stroke or myocardial infarction) beta blockers were associated with a higher risk of events then were other antihypertensive agents. Further, beta blockers showed no benefit compared to other antihypertensive agents or placebo regarding mortality. They appear to be less effective than other antihypertensive agents in reducing cardiovascular events. Contradictory results were found regarding the effect of beta blockers on stroke. None of the studies explored the effect on quality of life, hospitalisation, functional impairment/status, safety endpoints or renal failure.

CONCLUSION

The quality of current evidence to interpret the benefits of beta blockers in hypertension is rather weak. It cannot be recommended to use beta blockers in older adults as first line agent for hypertension.

Are beta-blockers efficacious as first-line therapy for hypertension in the elderly?

The aim of this paper is to assess antihypertensive efficacy of b-blockers and their effects on cardiovascular morbidity and mortality and all-cause mortality in elderly patients with hypertension. Randomized placebo-controlled trials, trials with untreated controls, and trials comparing antihypertensive drugs were selected from the literature. The relative risk reduction of primary endpoints and 95% confidence intervals were calculated. There were six trials in which elderly patients were treated with beta-blockers for hypertension (three trials were placebo-controlled, one trial had untreated controls, and two trials compared antihypertensive drugs). There was no study with monotherapy of beta-blockers. In combination with diuretics, beta-blockers were superior to placebo and untreated controls in preventing cardiovascular events, especially strokes, but there was no superiority of beta-blockers to angiotensin-converting enzyme inhibitors and calcium antagonists in preventing cardiovascular morbidity and mortality and total mortality in elderly patients with hypertension. Beta-blockers are only efficacious in combination with diuretics in preventing cardiovascular morbidity and mortality in elderly patients with hypertension.

MRC trial of treatment in elderly hypertensives

The MRC trial was a random control comparison of placebo treatment with two active drug regimens: atenolol 50 mg daily and a combined tablet containing hydrochlorothiazide 25 mg and amiloride 2.5 mg. The trial was based on 226 general practices in the U.K. Its primary purpose was to determine whether hypotensive drug treatment in men and women aged 65-74 with systolic pressure in the range 160-209 mmHg and with diastolic pressure below 115 mmHg reduced stroke, coronary heart disease (CHD) and all-cause mortality. A secondary objective was to determine whether outcome differed with the two forms of active treatment. 4,396 patients were randomized: 50% to placebo; 25% each to the two forms of treatment. During the following 5.8 years 25,000 patient-years of experience accumulated. Blood pressure fell in the placebo group, larger falls occurred with the two active treatments. Active treatment (diuretic and beta-blocker groups combined) reduced stroke by 25% (95% CI 3 to 42%), CHD by 19% (-2% to 36%, p = 0.08), cardiovascular events by 17% (2% to 29%). Benefits were clearest for the diuretic regime: a 31% reduction of stroke events, a 44% reduction of CHD and a 35% reduction of cardiovascular events--all significant.