To the Editor We are concerned about the reporting by Tsugawa et al1 in a recently published Original Investigation in JAMA Internal Medicine. Their study summarized differences between male physicians and female physicians regarding mortality and readmission of Medicare patients. Risk differences were all small. The difference in mortality, for example, was only 0.42% (11.49% for male physicians; 11.07% for female physicians). Yet the authors state in the abstract that “…patients treated by female internists have lower mortality and readmissions compared with those cared for by male internists,”1(p206) a conclusion apparently based on a finding of statistically significant results. Small P values are a result of the huge sample size and not reflective of clinical significance. Further, the 95% CIs are very narrow, and in spite of this an important difference was still claimed.
Hayat MJ, Knapp TR. Limitations Concerning the Association of Physician Sex and Patient Outcomes. JAMA Intern Med. 2017;177(7):1057. doi:10.1001/jamainternmed.2017.2130