Assessing the Role of Patient-Physician Sex Concordance on Diagnostic Accuracy in Primary Care: A Randomized Factorial Survey Experiment

BACKGROUND: While the impact of patient-physician sex concordance on patient perceptions and outcomes has been studied, less is known about its influence on diagnostic accuracy in primary care. OBJECTIVE: Examine whether patient-physician sex concordance affects diagnostic accuracy among primary care physicians (PCPs) across a range of clinical case vignettes. DESIGN: Randomized factorial vignette-based survey experiment featuring five clinical cases (Hashimoto's thyroiditis, postural orthostatic tachycardia syndrome (POTS), relapsing-remitting multiple sclerosis (RRMS), syphilis, and systemic lupus erythematosus (SLE)), in which patient race (Black/White) and sex (male/female) were randomly assigned and all clinical content was held constant. PARTICIPANTS: PCPs from across the USA. MAIN MEASURES: For each clinical case, participants were asked to give three initial differential diagnoses, and after reviewing additional clinical information, they were asked to provide a final diagnosis. Participant's text-based responses were reviewed for accuracy. We used chi-square tests to compare the proportion of correct diagnoses between sex concordant and discordant patient-physician pairs. We also stratified the proportion of correct diagnoses by participant's sex and the randomly assigned race-sex version of each case. KEY RESULTS: Among 1027 PCPs (42.8% female, mean age 52.0 ± 12.0 years), patient-physician sex concordance did not significantly affect diagnostic accuracy for all five cases. However, female physicians tended to outperform male physicians across multiple vignettes at initial and final diagnosis. For example, female PCPs demonstrated higher diagnostic accuracy in identifying the final diagnosis of POTS (51.8% vs. 41.7%) and syphilis (68.0% vs. 55.3%) compared to male PCPs. In all cases except RRMS, female PCPs demonstrated greater diagnostic accuracy than male PCPs when assessing Black female cases. CONCLUSIONS: Patient-physician sex concordance did not affect diagnostic accuracy, but female physicians outperformed male physicians across several cases. Findings highlight the need to address physician-level factors to improve diagnostic equity in primary care.