Nifedipine and mortality risk in the elderly: relevance of drug formulation, dose and duration.

PURPOSE: This study examines the risk of all-cause and cardiac-related mortality associated with calcium channel blockers (CCBs) and other antihypertensives/diuretics compared with beta-blockers among an elderly cohort. We explored variations in mortality risk according to CCB formulation, dose and duration of use.

METHODS

Data are from the clinical sample of the Canadian Study of Health and Aging, a population-based prospective study of community and institutional residing persons aged 65+ years. The sample comprised 837 subjects without dementia and reporting use of 1+ antihypertensive/diuretic agents at baseline (1991) and with survival data during follow-up (1996).

RESULTS

Risk of all-cause and cardiac-related mortality was significantly higher among nifedipine users (HR=1.85, 95%CI 1.12, 3.05 and HR=2.22, 95%CI 1.02, 4.84, respectively) compared with beta-blocker users. After adjusting for covariates, the hazard ratios (95% confidence interval) for selected drug classes compared with beta-blockers were: nifedipine HR=1.82 (1.09-3.04), diltiazem/verapamil HR=0.96 (0.58-1.60), loop diuretics HR=1.84 (1.21-2.82), ACE inhibitors HR=0.98 (0.54-1.78) and other diuretics/antihypertensives HR=1.10 (0.70-1.72). Among nifedipine users, mortality risk increased with average daily dose and with recent (</=6 months) initiation of therapy and remained significant for prolonged-acting formulations.

CONCLUSIONS

Older subjects exposed to the dihydropyridine calcium antagonist nifedipine had a significantly higher risk for all-cause and cardiac-related mortality during the 5-year follow-up than subjects using beta-blockers. Copyright (c) 2000 John Wiley & Sons, Ltd.