CALCIUM-CHANNEL BLOCKERS AND CARDIAC MORTALITY IN THE TREATMENT OF HYPERTENSION - A REPORT FROM THE DEPARTMENT-OF-HEALTH HYPERTENSION CARE COMPUTING PROJECT (DHCCP)

Objective: A case control study has reported a 60% higher risk of myoc ardial infarction in hypertensives treated with a calcium channel bloc ker (CCB). We examined the Department of Health Hypertension Care Comp uting Project (DHCCP) data to see if we could confirm or refute this s uggestion, Design: Two case control studies, matched and unmatched, pl us two longitudinal studies from 1 year of presentation, one for all s ubjects given a CCB for more than 1 year compared with those not given this drug, and the second comparing survival on the different drugs i nitially given between 3 and 12 months of follow-up. Subjects: A total of 9328 subjects were included in the analyses and 2154 died. Of thes e, 6406 received one or more of the following index drugs: 26% a calci um channel blocker (CCB); 84% a diuretic; 29% alpha methyldopa; 12% a beta-blocker (BE); and 11% an angiotensin-converting enzyme (ACE) inhi bitor. The CCBs were nifedipine, diltiazem or verapamil, Results: In t he case control studies a group given diuretics +/- other treatments ( but not including one of the index drugs) provided a reference group w ith a relative risk (RR) of 1.0. In the matched case control study the adjusted RR for a CCB without a diuretic was 1.32 (95% CI 0.64-2.70) for IHD mortality and 1.05 (95% CI 0.60-1.84) for cardiovascular morta lity. Similar results were observed for methyldopa, BBs and ACE inhibi tors. The results in the unmatched case control analysis were also sim ilar. The longitudinal study comparing all those treated for over 1 ye ar with a CCB with all other treatments showed a RR for total mortalit y of 1.03 (95% CI 0.85-1.25). The longitudinal study of total mortalit y according to treatment initiated at 3-12 months found results of a s imilar magnitude for CCBs, methyldopa and BBs, Conclusions: The refere nce diuretic group had less severe cardiovascular disease than other g roups. Treatment with a CCB, BE or methyldopa was associated with an e xcess mortality in comparison with this reference group. The excess wa s similar in the different drug groups.