MRC trial of treating hypertension in older adults: Authors' reply

the patients were lost to follow up.This would be unacceptable in any trial in acute myocardial infarction or heart failure, in which I have considerable experience; I cannot understand why a study in hypertension would be different.This loss of patients indicates that the investigators have had serious problems monitoring their patients.Furthermore, it is known that patients lost to follow up differ from patients who remain in trials.Secondly, the number of patient years during which patients received treatment as a proportion of the total number of patient years in the sub- groups was 69% in the diuretic group, 55% in the 3 blocker group, and 69% in the placebo group.Obviously, ifclose to 50% ofthe assigned treatment is not administered it will not be possible to observe any effect.Thirdly, the number of withdrawals from 6 blocker treatment in this single blind study is in contrast to the experience in the Swedish trial in old patients with hypertension (STOP trial)2: 177 patients treated with I6 blockers in the Medical Research Council's trial were withdrawn because of bradycardia compared with none in the STOP trial (B Dahlof, personal communication).Fourthly, the power of the trial was calculated to study active treatment versus placebo.There is clearly insufficient power to permit conclusions regarding lack of effects between the treatment subgroups and placebo group-even more so considering my second point above.Wisely, the STOP trial did not present its subgroup results.None of these important flaws is discussed by the authors.I suggest that the trial should be discussed more in the context of pitfalls and flaws than in the context of treatment of hypertension.