Antihypertensive Treatment and Secondary Prevention of Cardiovascular Disease Events Among Persons Without Hypertension: A Meta-Analysis
Does treatment with antihypertensive medications among patients with a history of cardiovascular disease (CVD), but not hypertension reduce the risk of death and future CVD events?
This study was a meta-analysis of eligible studies identified from MEDLINE (from1950 to January 2011), EMBASE, and the Cochrane Collaboration Central Register of Controlled Clinical Trials, and manual examination of references in selected articles. Studies were included if they were randomized controlled trials of antihypertensive treatments including patients with blood pressure <140 mm Hg systolic and/or <90 mm Hg diastolic. A total of 874 papers were identified, from which 25 trials met inclusion/exclusion criteria. Information on participant characteristics, trial design and duration, treatment drug, dose, control, and clinical events was extracted using a standardized protocol. Outcomes included stroke, myocardial infarction (MI), congestive heart failure (CHF), composite CVD outcomes, CVD mortality, and all-cause mortality.
Participants who received antihypertensive medications had a reduced risk for stroke (relative risk [RR], 0.77; 95% confidence interval [CI], 0.61-0.98), for MI (RR, 0.80; 95% CI, 0.69-0.93), for CHF (RR, 0.71; 95% CI, 0.65-0.77), and for composite CVD events (RR, 0.85; 95% CI, 0.80-0.90) compared to controls. Both CVD mortality (RR, 0.83; 95% CI, 0.69-0.99) and all-cause mortality (RR, 0.87; 95% CI, 0.80-0.95) were also lower among participants on antihypertensive medications compared to controls. The corresponding absolute risk reductions per 1,000 persons were −7.7 (95% CI, −15.2 to −0.3) for stroke, −13.3 (95% CI, −28.4 to 1.7) for MI, −43.6 (95% CI, −65.2 to −22.0) for CHF events, −27.1 (95% CI, −40.3 to −13.9) for composite CVD events, −15.4 (95% CI, −32.5 to 1.7) for CVD mortality, and −13.7 (95% CI, −24.6 to −2.8) for all-cause mortality. Results did not differ according to trial characteristics or subgroups defined by clinical history.
The authors concluded that among patients with clinical history of CVD but without hypertension, antihypertensive treatment was associated with decreased risk of stroke, CHF, composite CVD events, and all-cause mortality. Additional randomized trial data are necessary to assess these outcomes in patients without CVD clinical recommendations.
This meta-analysis suggests that use of antihypertensive therapies among patients with CVD can further reduce events. As the authors suggest, prior to changes in secondary prevention, randomized trials are warranted, particularly among diabetic patients.
Keywords: Myocardial Infarction, Stroke, Secondary Prevention, Heart Failure, Blood Pressure, Hypertension
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