A032: Outcome differences between ACE inhibitor and calcium channel blocker treated hypertensives

The objective of this study was to compare the influences on mortality of ACE inhibitors (ACEIs) and calcium channel blockers (CCBs) in hypertensive patients attending the Glasgow Blood Pressure Clinic (GBPC). The GBPC holds a computerised data base of 11,000 hypertensive patients record-linked with the Registrar General Scotland for information on death and cause of death. Between 1 January 1980 and 31 December 1995, 5,207 patients received prescriptions for antihypertensive drugs: ACEIs n = 1,559; CCBs n = 2,295. Results using Cox's proportional hazards model adjusted for age, sex and epoch (4 years) of first prescription are presented in the Table 1. Risk for patients receiving each drug class is expressed relative to that in patients never receiving that class.TABLE 1Table. Relative Risk in Treated Hypertensive Patients All cause (857 deaths) All vascular (564 deaths) CHD (349 deaths) ACEI 0.73 (p = 0.009) 0.77 (p = 0.02) 0.72 (p = 0.03) CCB 1.35 (p = 0.0002) 1.54 (p = 0.0001) 1.72 (p = 0.0001) Compared with risk in patients never treated with ACEIs or CCBs, all cause, CHD and vascular mortality was reduced in patients treated with ACEIs (but never CCBs) and increased in patients treated with CCBs (but never ACEIs). Patients exposed to both ACEIs and CCBs had intermediate levels of risk. In successive four year epochs, hazard ratios for CHD mortality CCB but never ACEI were 1.63, 1.83, 1.81 and 1.65 respectively; ACEI but never CCB 0.51, 0.65, 0.95, 0.74. Hypertensive patients treated with ACE inhibitors have a survival advantage. In contrast, treatment with CCBs is associated with a poorer outcome. Findings were consistent over time implicating newer as well as older drugs. The large number of well-documented fatal events and the prolonged duration of follow-up may have allowed the demonstration of mortality differences not apparent in relatively short-term prospective trials.