To the Editor In their Original Investigation in a recent issue of JAMA Internal Medicine, Tsugawa and colleagues1 report that being treated by female rather than male internists is associated with lower 30-day mortality rates among hospitalized Medicare beneficiaries. Whether this association represents causation or residual confounding is unclear. The authors can perform 2 tests to help clarify the matter.
Friedberg MW, Gellad WF, Prasad V. Limitations Concerning the Association of Physician Sex and Patient Outcomes. JAMA Intern Med. 2017;177(7):1058. doi:10.1001/jamainternmed.2017.2142