Racial and Sex Differences in Postoperative Mortality Between Patients With Versus Without Dementia

Objective: To compare racial–sex differences in postoperative mortality by dementia status. Background: Because patients with dementia often find it harder to advocate for themselves, racial–sex differences in postoperative mortality may be greater for patients with dementia versus without dementia. Methods: Among Medicare fee-for-service beneficiaries aged 65 to 99 years who underwent one of 12 common surgical procedures in 2016 to 2019, we compared 30-day postoperative mortality (death during the index hospitalization or within 30 days of surgery) across 4 race–sex groups (Black men [reference group], White men, White women, and Black women) stratified by dementia status. Elective and nonelective surgeries were examined separately. Results: Among 888,391 patients undergoing elective surgery, 65,450 (7.4%) had dementia. Postoperative mortality was highest among Black men, both with dementia (adjusted mortality, 3.99%) and without dementia (2.11%). Racial–sex differences were generally greater among patients with dementia. For example, the mortality difference between White women versus Black men was significantly larger among patients with dementia (adjusted difference, −2.38 percentage points [pp]; 95% confidence interval [CI], −3.34 to −1.41) than among those without dementia (−0.75 pp; 95% CI, −0.96 to −0.54) ( P -for-interaction = 0.001). In contrast, among 394,554 patients undergoing nonelective surgery, 56,273 (14.3%) had dementia, and we found no evidence that mortality was highest among Black men or that racial–sex differences meaningfully varied by dementia status. Conclusions: Among patients undergoing elective surgery, racial–sex differences in postoperative mortality were greater among patients with dementia than among those without dementia, highlighting the need for targeted strategies to ensure consistent surgical care.