Author + information
- Steven S. Khan, MD⁎ ()
- ↵⁎Kaiser-Permanente Hospital, UCLA School of Medicine, Cardiology, 1526 North Edgemont, 2nd Floor, Los Angeles, California 90027
Bangalore et al. (1) have provided an intriguing observation that cardiovascular (CV) events, including CV death, myocardial infarction, heart failure, stroke, and all-cause death, may be increased in hypertensive patients placed on beta-blockers and that this may be related to the degree of heart rate reduction. They have done this by performing meta-regression analyses to demonstrate the relationship between heart rate and cardiovascular outcomes.
However, the data in their graphs show that the regression lines cross the line of unity. The 1 study that is consistently at or below unity in their graphs is the IPPSH (International Prospective Primary Prevention Study in Hypertension), which compared a beta-blocker with placebo. Similarly, the only other placebo-controlled trial analyzed, STOP (Swedish Trial in Old Patients with Hypertension) (2), shows a relative risk of about 0.9 in Figure 4 of Bangalore et al. (1). This suggests that beta-blockers are not increasing CV events because there is no increase in events in beta-blocker patients compared with placebo patients. The major differences in outcome rates are in the studies comparing beta-blockers with active controls.
These findings suggest that beta-blockers were less effective at preventing CV events than other antihypertensive agents. The mechanism for this may be evident in Table 2 of Bangalore et al. (1), which shows that beta-blockers resulted in less blood pressure reduction in 5 of 7 active control trials analyzed by the authors, with up to a 9.2-mm Hg difference in systolic blood pressure. This suggests that beta-blockers were simply less effective antihypertensive agents in general. Thus, an alternative interpretation of the authors' findings is not that beta-blockers increase mortality, as has been widely reported in the press, but that beta-blockers are simply less effective antihypertensive agents than diuretics or dihydropyridine calcium-channel blockers. As a result, they are also less effective at preventing hypertension-related cardiovascular events than other medications. The clinical message I would take from this study is that we must remember that the primary goal of antihypertensive treatment is to lower blood pressure and not to lower heart rate.
- American College of Cardiology Foundation