Retrospective longitudinal cohort study comparing the effects of angiotensin-converting enzyme inhibitors and long-acting calcium channel blockers on total and cardiovascular mortality in patients with hypertension

Abstract

Background: There is controversy regarding the impact that different antihypertensive regimens, including modern combination therapy, have on the incidence of myocardial infarction, other cardiovascular events, and mortality.

Objective: The objective of this study was to determine and compare the effects of treatment strategies based on angiotensin-converting enzyme (ACE) inhibitors and long-acting calcium channel blockers (CCBs) on total and cardiovascular mortality in hypertensive patients in a usual-care setting.

Methods: This retrospective, longitudinal cohort study used integrated medical and pharmacy claims data from a geographically diverse administrative database of >8 million persons in the United States. Patients aged > or = 18 years with hypertension were eligible if they had filled a prescription for either an ACE inhibitor or a long-acting CCB between January 1, 1995, and June 30, 1999 (the index prescription). Patients who had a prescription for any antihypertensive agents before the index prescription were excluded, as were eligible ACE inhibitor-treated patients who used CCBs or CCB-treated patients who used ACE inhibitors during the follow-up period. Use of all other antihypertensive medications was permitted. Patients were matched using a propensity score generated from a logistic regression model. A survival-analysis approach was used to compare mortality between groups. The final cohorts were assessed through June 30, 2002.

Results: A total of 18,199 patients met the study inclusion criteria; 12,608 (69.3%) used an ACE inhibitor and 5,591 (30.7%) used a CCB. The mean follow-up was approximately 4.4 years. After cohort matching using the propensity score, the study population consisted of 10,926 patients, 5,463 matched patients in each group. The adjusted hazard ratios (95% CIs) for all-cause, cardiovascular, congestive heart disease, and congestive heart failure mortality in the ACE-inhibitor group compared with the CCB group for the entire follow-up period were 0.70 (0.63-0.79), 0.65 (0.53-0.80), 0.47 (0.32-0.70), and 0.74 (0.49-1.12), respectively.

Conclusion: Analysis of a large medical and pharmacy database suggests that an ACE inhibitor-based treatment strategy is associated with reduced mortality compared with a CCB-based strategy in patients with hypertension in a managed care setting.