Importance Hospitalized medical patients cared for by female physicians may have decreased mortality rates compared with patients of male physicians. However, this association has yet to be assessed outside of the US, and little is known about factors that may explain this difference. Objective To determine whether mortality, other hospital outcomes, and processes of care differed between the patients cared for by female and male physicians. Design, Setting, and Participants This retrospective cross-sectional study included patients admitted to general medical wards at 7 hospitals in Ontario, Canada, between April 1, 2010, and October 31, 2017. The association of physician gender with patient outcomes was examined while adjusting for hospital fixed effects, patient characteristics, physician characteristics, and processes of care. All patients were admitted to a general internal medicine service through the emergency department and were cared for by a general internist or family physician-hospitalist. Patients were excluded if length of stay was greater than 30 days or if the attending physician cared for less than 100 hospitalized general medicine patients over the study period. Statistical analyses were performed from October 15, 2020, to May 8, 2021. Main Outcomes and Measures In-hospital mortality, length of stay, intensive care unit admission, 30-day readmissions, and process-of-care measures (blood tests, medications, imaging, endoscopy, and interventional radiology services). Results A total of 171 625 hospitalized patients with a median age of 73 years (interquartile range, 56-84 years) were included (84 221 men [49.1%], 87 402 women [50.9%], and 2 patients with unspecified sex). Patients were cared for by 172 attending physicians (54 female physicians [31.4%] and 118 male physicians [68.6%]). In fully adjusted models, female physicians ordered more imaging tests, including computed tomography (adjusted difference, -1.70%; 95% CI, -2.78% to -0.61%; P = .002), magnetic resonance imaging (-0.88%; 95% CI, -1.37% to -0.38%; P = .001), and ultrasonography (-1.90%; 95% CI, -3.21% to -0.59%; P = .005). Patients treated by female physicians had lower in-hospital mortality (2256 of 46 772 patients [4.8%] vs 6452 of 124 853 patients [5.2%]). This difference persisted after adjustment for patient characteristics but was no longer statistically different after adjustment for other physician characteristics (adjusted difference, 0.29%; 95% CI, -0.08% to 0.65%; P = .12). The difference was similar after further adjustment for processes of care. Conclusions and Relevance In this cross-sectional study of patients admitted to general medical units in Canada, patients cared for by female physicians had lower mortality rates than those treated by male physicians, adjusting for patient characteristics. This finding was nonsignificant after adjustment for other physician characteristics. This cross-sectional study investigates the association of physician gender with mortality and patient outcomes in a general medicine inpatient setting. Question Is physician gender associated with mortality and other patient outcomes in a general internal medicine inpatient setting? Findings In this cross-sectional study of 171 625 hospitalized patients, patients cared for by female physicians had lower in-hospital mortality after adjustment for hospital and for patient characteristics, but this was no longer statistically different after adjustment for physician characteristics. Meaning The lower mortality rate in patients cared for by female physicians may be partially explained by differences in physician characteristics.
