Effect of angiotensin-converting-enzyme inhibition compared with conventional therapy on cardiovascular morbidity and mortality in hypertension: the Captopril Prevention Project (CAPPP) randomised trial.

BACKGROUND: Angiotensin-converting-enzyme (ACE) inhibitors have been used for more than a decade to treat high blood pressure, despite the lack of data from randomised intervention trials to show that such treatment affects cardiovascular morbidity and mortality. The Captopril Prevention Project (CAPPP) is a randomised intervention trial to compare the effects of ACE inhibition and conventional therapy on cardiovascular morbidity and mortality in patients with hypertension. METHODS: CAPPP was a prospective, randomised, open trial with blinded endpoint evaluation. 10,985 patients were enrolled at 536 health centres in Sweden and Finland. Patients aged 25-66 years with a measured diastolic blood pressure of 100 mm Hg or more on two occasions were randomly assigned captopril or conventional antihypertensive treatment (diuretics, beta-blockers). Analysis was by intention-to-treat. The primary endpoint was a composite of fatal and non-fatal myocardial infarction, stroke, and other cardiovascular deaths. FINDINGS: Of 5492 patients assigned captopril and 5493 assigned conventional therapy, 14 and 13, respectively, were lost to follow-up. Primary endpoint events occurred in 363 patients in the captopril group (11.1 per 1000 patient-years) and 335 in the conventional-treatment group (10.2 per 1000 patient-years; relative risk 1.05 [95% CI 0.90-1.22], p=0-52). Cardiovascular mortality was lower with captopril than with conventional treatment (76 vs 95 events; relative risk 0.77 [0.57-1-04], p=0.092), the rate of fatal and non-fatal myocardial infarction was similar (162 vs 161), but fatal and non-fatal stroke was more common with captopril (189 vs 148; 1.25 [1-01-1-55]. p=0.044). INTERPRETATION: Captopril and conventional treatment did not differ in efficacy in preventing cardiovascular morbidity and mortality. The difference in stroke risk is probably due to the lower levels of blood pressure obtained initially in previously treated patients randomised to conventional therapy.

The Captopril Prevention Project (CAPPP) in hypertension--baseline data and current status.

The Captopril Prevention Project (CAPPP) is an ongoing intervention study conducted in 11,019 hypertensive patients in Sweden and Finland. Patients have been randomized to receive either conventional antihypertensive therapy (diuretics and/or beta-blockers) or captopril-based treatment. A prospective, randomized, open, blinded-endpoint evaluation (PROBE) study design is used to compare these two therapeutic regimens as regards cardiovascular morbidity and mortality. The rationale for the CAPPP Study are the many observations of beneficial effects of ACE inhibition, as compared to diuretics and beta-blockers, on intermediary endpoints such as insulin sensitivity, serum lipoproteins, left ventricular hypertrophy and renal function. Captopril has also been shown to be markedly effective in the treatment of left ventricular dysfunction as well as congestive heart failure. The hypothesis is that these differences might result in improved risk reduction when ACE inhibitors are used in the treatment of hypertension. The present paper describes the baseline data and the changes in blood pressure during the first year in the total cohort. During the first year the average blood pressure was reduced by 11/8 mm Hg. A number of substudies have been conducted in the CAPPP Study. In one of these insulin sensitivity was compared in a subgroup of the patients using the euglycemic insulin clamp technique. In another substudy the ACE gene was sequenced and some new polymorphisms were discovered. Several other substudies are in progress or in the planning phase. The main results of the CAPPP Study should be available by mid-1998. Some of the intended anayses of the final results as well as other planned substudies are briefly described here.