Objective: Recent studies have shown inconsistent results on the risk of cancer in hypertensive patients using calcium channel blockers (CCBs) and angiotensin-converting enzyme (ACE) inhibitors. We investigated a large number of patients from the Department of Health Hypertension Care Computing Project (DHCCP) observational database treated with these drugs for hypertension to see whether the use of CCBs for hypertension is associated with an increased risk of cancer mortality and the use of ACE inhibitors with a reduction.
Design: Matched case-control study and a longitudinal study of survival from 1 year after presentation.
Patients: A total of 11663 patients treated for hypertension from 1971 through 1987. They were recruited on presentation to one of the hospital hypertension clinics or general practices involved.
Main outcome measures: Death with any mention of cancer on the death certificate in patients treated with an Index drug group; CCBs, ACE inhibitors, beta adrenergic blocking drugs (BBs), or receiving a diuretic. The treatment groups were mutually exclusive.
Results: A total of 391 cases of cancer were matched with 1050 controls. In this case-control study the adjusted relative risk estimate in comparison to diuretic treatment for CCBs was 0.79 (95% CI 0.37 to 1.69), and for CCBs plus a diuretic, 1.05 (0.65 to 1.69). Non-significant results were also observed for ACE inhibitors (1.48 (0.43 to 5.1), and 1.40 (0.56 to 3.50) with a diuretic), and also for the BB and methyldopa groups. In the longitudinal survival study, the adjusted relative risk estimate for CCBs was 1.1 (0.60 to 1.94) and 1.0 (0.53 to 1.86) for CCBs plus a diuretic, and for ACE inhibitors 1.33 (0.37 to 4.76) and 1.47 (0.67 to 3.23), respectively.
Conclusions: In this population there was no increased cancer mortality with the use of CCBs and a relative risk greater than 1.7 to 2.0 was excluded with 95% confidence. The suggestion that ACE inhibitors reduce cancer mortality was not supported with best estimates of relative risk of 1.3 to 1.5 and exclusion of values less than 0.4 to 0.7.