Importance: Although there have been increased efforts in dermatologic research to improve representation of patient sex, race, and ethnicity, there are limited data evaluating resulting changes. Objective: To characterize the diversity of participants in dermatologic clinical trials conducted in the US published from 2015 to 2020 pertaining to common dermatologic conditions affecting all patient demographic categories compared with findings from 2010-2015. Evidence Review: A systematic literature review through the PubMed database was conducted for randomized clinical trials published between July 1, 2015, and July 1, 2020, using keywords alopecia areata, acne, atopic dermatitis, lichen planus, psoriasis, seborrheic dermatitis, and vitiligo. Data collected included distribution of participant demographic characteristics, funding source, and journal type. Reflecting US Census data, studies were defined as unrepresentative of race and ethnicity if they included less than 20% ethnically or racially diverse participants or unrepresentative of sex if they included less than 45% women. Python was used for statistical analysis by χ2tests or Fisher exact tests. Findings: A total of 392 randomized clinical trials were included. In comparison with the period from 2010-2015, the reporting rate for race and ethnicity in US studies has increased from 59.8% to 71.9% (P =.05). However, the proportion of reporting articles including at least 20% non-White representation remains unchanged at 38.1% with 37 of 97 reporting randomized clinical trials in 2010-2015 and 53 of 139 reporting randomized clinical trials in 2015-2020 (P =.99). Psoriasis studies included the least diversity, with 12.1% of studies recording at least 20% non-White participants and 29.5% of studies recording at least 45% female participants. Conclusions and Relevance: The findings of this systematic review suggest that reporting racial and ethnic data since 2010-2015 has become more transparent. However, inclusion of representative patient populations may still be considered inadequate, particularly in psoriasis studies. Diversity in clinical trials is important for representation of the affected patient populations, and additional efforts are warranted in support of this endeavor.
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