Age, Race, Ethnicity, and Sex of Participants in Clinical Trials Focused on Chronic Pain

There is limited data on equitable inclusion in chronic pain trials. We aimed to 1) identify the frequency of reporting age, race, ethnicity, and sex in clinical trials targeting chronic pain, and 2) compare sociodemographic representation to the United States (US) population. We examined US-based intervention trials for chronic pain initiated between 2007 and 2021 and registered on ClinicalTrials.gov. We 1) assessed the frequency of reporting each demographic variable, 2) compared representation with US population estimates, and 3) explored change in reporting over time. Of 501 clinical trials, the frequency of reporting was as follows: 36.9% reported older adults, 54.3% reported race, 37.4% reported ethnicity, and 100% reported sex. Rates of race and ethnicity reporting increased, but older adult age reporting decreased over time (ps < .00001). Compared to 2020 US population estimates, there was an equitable representation of older adults, under-representation of individuals identifying as American Indian or Alaska Native (.8% vs .6%), Asian (5.6% vs 2.9%), Black or African American (12.6% vs 12.2%), with more than one race (2.9% vs 1.2%), and Hispanic/Latino (16.9% vs 14.1%). There was an over-representation of individuals identifying as Native Hawaiian or Pacific Islander (.2% vs .5%) or White (70.4% vs 72.9%), and of females (50.8% vs 68.4%). Some representation rates varied by chronic pain condition. Reporting of older adult age, race, and ethnicity was low in chronic pain trials in ClinicalTrials.gov, reinforcing the need for adhering to reporting guidelines. Representation varied across trials compared with US population data, particularly among those identifying as Hispanic/Latino and certain minority racial groups.

Perspective

Despite initiatives to increase the reporting of demographic information, doing so in clinical pain trials is far from ubiquitous. Moreover, efforts to improve diversity in these trials continue to be insufficient. Indeed, Black, Indigenous, and People of Color (BIPOC) remain under-represented in clinical pain trials.