ACE inhibitors and beta-blockers were equally as effective in lowering blood pressure and preventing cardiovascular events in patients whose blood pressure could not be controlled by a thiazide diuretic and had no indication for a second-line treatment, according to a comparative-effectiveness study published in the September issue of Circulation: Cardiovascular Quality and Outcomes.
Because research is sparse and the most optimal second-line therapy for patients not adequately controlled by a thiazide diuretic remains unknown, David J. Magid, MD, from the University of Colorado in Denver, and colleagues assessed data of hypertensive adults between 2002 and 2007 who were on thiazide monotherapy and then administered either an ACE inhibitor or beta-blocker.
The researchers used blood pressure control at one-year after the initiation of the second-line agent—beta-blocker or ACE inhibitor—as the study’s primary endpoint.
The researchers compared data of 15,540 hypertensive patients enrolled in three large integrated healthcare delivery systems—9,622 patients were prescribed an ACE inhibitor and 5,918 patients received beta-blockers. According to Magid and colleagues, more patients were prescribed beta-blockers earlier on in the study as compared to the later years where more ACE inhibitors were prescribed.
Patients in both groups had similar characteristics; however, blood pressure was higher in patients administered beta-blockers—152.7/90 versus 151.8/89. Additionally, more men were prescribed ACE inhibitors, while more patients administered beta-blockers had hyperlipidemia.
Study results showed that differences between blood pressure control in patients administered ACE inhibitors and beta-blockers did not statistically differ, 70.5 percent versus 69 percent, respectively. Researchers found incident rates of MI and stroke to have hazard ratios of 1.05 and 1.01, respectively. Incidence rates of congestive heart failure and kidney disease were also not statistically different.
There was a slightly higher number of patients who were administered a new blood pressure lowering agent over a one-year time frame in the ACE inhibitor group compared to the beta-blocker group, 24 percent versus 21.9 percent, respectively. Of these patients prescribed a new antihypertensive agent, the new agent was most likely a substitution for an ACE inhibitor as opposed to a beta-blocker, 18.9 percent versus 9.3 percent, respectively.
“Our findings that ACE inhibitors and beta-blockers are equally effective in lowering blood pressure and preventing CV events suggest that either is a reasonable choice for add-on therapy for patients not controlled with a thiazide monotherapy,” the authors wrote.