Persistence of mortality reduction after the end of randomized therapy in clinical trials of blood pressure-lowering medications

Abstract

Long-term follow-up of clinical trials of blood pressure-lowering medications has suggested a continuation of event reduction after study completion. We evaluated the persistence of mortality benefit of these agents after the end of clinical trials, when all of the patients were advised to take the same open-label therapy. We performed a meta-analysis of randomized clinical trials using blood pressure-lowering medications, used in patients with hypertension, myocardial infarction, or left ventricular systolic dysfunction, (n=18; 132 854 patients; 11 988 deaths) when a second report describing results after the end of the trial was available. During the randomized (first) phase, 80% (interquartile range: 75% to 83%) of the patients randomized to receive active therapy actually received it compared with 16% (interquartile range: 7% to 22%) of those randomized to control. In this phase, mortality was lower in the intervention group (odds ratio: 0.84 [95% CI: 0.79 to 0.90]; P<0.0001). Mortality was also lower during the open-label follow-up (second) phase (odds ratio: 0.85 [95% CI: 0.79 to 0.91]; P<0.0001), when all of the patients were advised to take the same therapy, and rates of receiving active therapy were similar in the 2 groups (59% [interquartile range: 46% to 77%], among those originally randomized to active, and 43% [interquartile range: 20% to 68%], in the control). Several sensitivity analyses indicated stability of the effects. In studies of antihypertensive medications, a decrease in overall mortality persists after the end of trial phase, when most patients in both the intervention and control groups receive active therapy. These analyses imply that earlier intervention would result in better clinical outcomes.