Statistical Methods to Examine Racial and Ethnic Disparities in the Surgical Literature: A Review and Recommendations for Improvement.

Objective: To characterize the quality of statistical methods for studies of racial and ethnic disparities in the surgical-relevant literature during 2021-2022.

Background: Hundreds of scientific papers are published each year describing racial and ethnic disparities in surgical access, quality, and outcomes. The content and design quality of this literature have never been systematically reviewed.

Methods: We searched for 2021 to 2022 studies focused on describing racial and/or ethnic disparities in surgical or perioperative access, process quality, or outcomes. Identified studies were characterized in terms of 3 methodological criteria: (1) adjustment for variables related to both race/ethnicity and outcomes, including social determinants of health (SDOH), (2) accounting for clustering of patients within hospitals or other subunits ("providers"), and (3) distinguishing within-provider and between-provider effects.

Results: We identified 224 papers describing racial and/or ethnic differences. Of the 38 single-institution studies, 24 (63.2%) adjusted for at least one SDOH variable. Of the 186 multisite studies, 113 (60.8%) adjusted for at least one SDOH variable, and 43 (23.1%) accounted for the clustering of patients within providers using appropriate statistical methods. Only 10 (5.4%) of multi-institution studies made efforts to examine how much of the overall disparities were driven by within versus between-provider effects.

Conclusions: Most recently published papers on racial and ethnic disparities in the surgical literature do not meet these important statistical design criteria and, therefore, may risk inaccuracy in the estimation of group differences in surgical access, quality, and outcomes. The most potent leverage points for these improvements are changes to journal publication guidelines and policies.