ACE Inhibitor-Based Treatment and Cardiovascular Outcomes in Hypertensive Blacks vs. Whites
What is the comparative effectiveness of an angiotensin-converting enzyme (ACE) inhibitor (ACEi)-based regimen on a composite outcome of all-cause mortality, stroke, and acute myocardial infarction (AMI) in hypertensive blacks compared to whites?
A retrospective cohort study was conducted in 434,646 patients in a municipal health care system. Four exposure groups (Black-ACEi, Black-NoACEi, White-ACEi, White-NoACEi) were created based on race and first drug treatment exposure (ACEi or NoACEi). Risk of the composite outcome and its components was compared across treatment groups and race using weighted Cox proportional hazard models. NoACEi included beta-blockers, thiazide diuretics, and calcium channel blockers.
There were 59,316 new users of ACEi, 47% of whom were black. Baseline characteristics were comparable for all groups after inverse probability weighting adjustment. For the composite outcome, the race treatment interaction was significant (p = 0.04); ACEi use in blacks was associated with poorer cardiovascular outcomes (ACEi vs. NoACEi: 8.69% vs. 7.74%; p = 0.05), but not in whites (6.40% vs. 6.74%; p = 0.37). Similarly, the Black-ACEi group had higher rates of AMI (0.46% vs. 0.26%; p = 0.04), stroke (2.43% vs. 1.93%; p = 0.05), and chronic heart failure (CHF) (3.75% vs. 2.25%; p < 0.0001) than the Black-NoACEi group. Hazard ratios indicated the differences were significant only for AMI and CHF. The findings did not change when adjusted for differences between black-white differences in achieved systolic blood pressure. The Black-ACEi group was no more likely to develop adverse effects than the White-ACEi group.
ACEi-based therapy was associated with poorer cardiovascular outcomes in hypertensive blacks, but not in whites. These findings confirm clinical trial evidence that hypertensive blacks have poorer outcomes than whites when treated with an ACEi-based regimen.
The results are clinical confirmation of less efficacy or an increase in morbidity associated with use of ACEi in blacks when used for hypertension. In the ALLHAT trial, those randomized to ACEi had poorer outcome and lower blood pressure than those randomized to a thiazide diuretic. Similarly, whites treated with ACEi in the SOLVD study had a decrease in hospitalization for CHF, but blacks had no benefit. The study does not refute the posit that the cardiovascular event rate in blacks is higher for the same blood pressure or ACEi are not as effective as first-line therapy in blacks (the 2014 evidence-based guideline for management of hypertension in US adults precludes use of ACEi as first-line treatment).
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