Importance: Though there have been significant shifts in US demographic data over the past 50 years, research cohorts lack full racial and ethnic representation. There is little data available regarding the diversity of dermatology research cohorts with respect to sex, race, and ethnicity.
Objective: To characterize and assess the representation of racial and ethnic minorities and women in randomized controlled trials across a range of dermatologic conditions.
Evidence review: All randomized clinical trials (RCTs) were identified between July 2010 and July 2015 within the PubMed database using the following keywords: "psoriasis," "atopic dermatitis," "acne," "vitiligo," "seborrheic dermatitis," "alopecia areata," and "lichen planus." Diverse study populations were defined as including a greater than 20% racial or ethnic minority participants based on US census data. The distributions of sex and race groups in studies were compared by journal type, disease type, and funding source.
Findings: Of the 626 articles reporting RCTs included in this analysis, 532 (85.0%) reported the sex of study participants. Overall, 52 of 626 international (11.3%) studies and 58 of 97 studies (59.8%) conducted exclusively within the United States reported on the racial or ethnic demographics of study participants. Across all RCTs exclusively recruited within the United States that reported race, 74.4% of study participants were white. Disease type was significantly associated with the degree of racial diversity (P < .001) within a study cohort: 30.0% of US-based psoriasis had more than 20% racially or ethnically diverse research participants as compared with 73.9% of acne studies and 91.7% of eczema studies.
Conclusion and relevance: Dermatologic clinical trials within the United States reflect the growing diversity of the US population. Reporting of both sex and racial/ethnic diversity of research cohorts is still lacking, especially among studies conducted outside of the United States.