MYOCARDIAL-INFARCTION AND STROKE DURING TREATMENT OF HYPERTENSIVE PATIENTS WITH DIFFERENT DIURETIC REGIMES

A retrospective analysis of mortality and cardiovascular morbidity in patients being treated with a potassium losing diuretic alone or the combination of a potassium losing and sparing diuretic was performed in 1,935 patients attending a hypertension clinic between 1971 and 1981. In all, 713 patients were treated with a potassium losing diuretic and 472 patients were on a potassium sparing diuretic, usually in combination with a potassium loser. Presenting data on risk factors were similar between the two groups and age-adjusted cardiovascular morbidity and mortality was similar between the two groups. The relative risk (RR) for a myocardial infarction event on a potassium losing drug was 1.1 (95% CI 0.5-2.3) in men and 1.0(0.4-2.5) in women. The corresponding risks for stroke were 0.8 and 0.7 respectively and total mortality was 1.3 and 1.1. However, following exclusion of patients with previous history of cardiovascular disease the risk of myocardial infarction in the potassium losing group was over three times that on a sparing diuretic, though the confidence intervals were wide. Total male mortality tended to be higher (RR = 2.4) but again failed to achieve statistical significance. An excess risk from potassium losing diuretics was found only in patients without cardiovascular disease and cannot be readily explained. This may be the result of treatment selection in different 'at risk' groups or chance in the performance of subgroup analyses.