A randomized trial shows that a new throm-bolytic agent reduces total mortality in the first 30 days after a suspected myocardial infarction by 30 percent compared with a placebo (p<0.002). Which of the following questions would be the most important to have answered? (AIIMS May 11)
|A||Was the trial blinded?|
|B||What was the power of the study?|
|C||What happened to surviving patients in the next year?|
|D||What percentage of patients in each group actually had a myocardial infarction?|
a. The importance of blinding, while it usually cannot be overemphasized, is not relevant in a study with total mortality as the end point: it is not possible to misclassify someone as alive when that person is really dead (except with fraudulent results). Power is not relevant in a study that shows a significant effect.
b. In a randomized study, the percentages of patients who actually had myocardial infarctions should be similar in the two groups.
c. Total mortality is a much more important end point than mortality from coronary heart disease, but long-term follow-up is absolutely essential in determining whether a therapy is useful. Perhaps the new agent simply postpones mortality by a few days or weeks.