SUBGROUP ANALYSES ISSUE: ASTROLOGICAL BIRTH SIGN, FOR EXAMPLE
Student
[In a large trial], reliable indication of subgroups of patients among whom treatment is particularly advantageous (or among whom it is ineffective) is unlikely to be possible. When a trial is clearly positive overall many subgroup analyses are considered, false negative results in some particular subgroups must be expected. For example, a subdivision of the patients in [international streptokinase/aspirin trial] with respect to their astrological birth signs appears to indicate that for patients born under Gemini or Libra there was a slightly adverse effect of aspirin on mortality . . . while for all patients born under other signs there was a strikingly beneficial effect . . . It is, of course, clear that the best estimate of the real size of the treatment effect in each astrological subgroup is given not by the results in that subgroup alone but by the overall results in all subgroups combined.
