Level 2: Mid-level evidence
Beta blockers as monotherapy or first-line therapy were evaluated in a Cochrane review of 13 randomized trials with a total of 91,561 adults (Cochrane Database Syst Rev. 2007;:CD002003) and were generally found no better or inferior to other antihypertensive medications. Compared with placebo or no treatment, beta blockers were associated with a reduced incidence of stroke (1.8% vs. 2.3%, P=.02, NNT 200) and cardiovascular disease (CVD) (5.7% vs. 6.4%, P=.01, NNT 143) in four trials with 23,613 patients. But there were no significant differences in total mortality, coronary heart disease (CHD), or cardiovascular mortality.
In four trials that compared beta blockers with diuretics (N=18,135), there were no significant differences in total mortality, CHD, stroke, or CVD. The incidence of CVD tended to be higher with beta blockers (5.3% vs. 4.5%, P=.07). Compared with calcium channel blockers, beta blockers were associated with higher mortality in four trials with 44,825 patients (7.8% vs. 7.3%, P=.04, NNH 200), higher incidence of CVD in two trials with 19,915 patients (9.4% vs. 8.1%, P=.0003, NNH 77), and higher incidence of stroke in three trials with 44,167 patients (2.9% vs. 2.3%, P=.0002, NNH 166). There were no significant differences in CHD or cardiovascular mortality. In three trials that evaluated beta blockers vs. renin-angiotensin inhibitors (N=10,828), there were no significant differences in total mortality, CHD, cardiovascular mortality, or CVD.
Beta blockers were associated with an increased incidence of stroke (6.6% vs. 5.1%, P = .001, NNH 66) in two trials with 9,951 patients.
Seventy-five percent of the trials included in the Cochrane review used atenolol (Tenormin), so it is unclear whether the same conclusions apply to other beta blockers. Additional medications used in the original trials may also be a confounding factor.