To compare clinicians' ratings of therapeutic effectiveness when different trial end points were presented as percent reductions in relative compared with absolute risk and as numbers of patients treated to avoid one adverse outcome.
Survey, with random allocation of two questionnaires.
Toronto teaching hospitals.
Convenience sample of 100 faculty and housestaff in internal medicine and family medicine.
One questionnaire presented results for three end points of the Helsinki Heart Study as separate drug trials using only absolute differences in events; the other showed the same end points as relative differences. Both questionnaires included a fourth "trial," showing person-years of treatment needed to prevent one myocardial infarction.
The "trials" were each rated on an 11-point scale, from treatment "harmful" to "very effective."
Respondents' ratings of effectiveness varied with the end point. Controlling for end point, ratings of effectiveness by the 50 participants receiving absolute event data were lower than those by 50 participants responding to relative risk reductions (P
Notes
Comment In: Ann Intern Med. 1993 Jul 1;119(1):93-48498776
Comment In: Ann Intern Med. 1993 May 1;118(9):747; author reply 748-98379981