Trends in Patient Representation in Low Back Pain Pharmacological Randomized Clinical Trials, 2011 to 2020: A Systematic Review.

Low back pain (LBP) significantly affects global health, with associated detrimental outcomes such as physical impairment, emotional distress, and exacerbated mental health symptoms. This study evaluated the representation of marginalized groups, including racialized, gender minority, pregnant/lactating, and elderly individuals in randomized controlled trials for pharmacological interventions treating LBP from 2011 to 2020. We searched Embase, MEDLINE, and CINAHL in December 2021, and 139 studies were eligible. Most trials (n = 113, 81%) reported participant sex; however, no study collected data on sexual and gender minorities, and the majority (n = 99, 71%) excluded pregnant/lactating individuals. Most trials (n = 105, 76%) reported no data on participant race or ethnicity. We limited within-country analyses of race and ethnicity to US-based trials because US-based trials were more likely to report race and/or ethnicity (48%) compared to non-US-based trials (8%). Black participants were the only racialized group whose composition was comparable to US Census estimates. About half (n = 73, 53%) of all trials had an upper age limit for eligibility (range: 40-85 years old) and 24% (n = 33) excluded adults aged >65 years. Our findings confirm that trials for pharmacological LBP interventions underreport demographic data, and the trials that include this data have unrepresentative samples. There is an urgent need for more inclusive and representative patient samples to ensure generalizability and equitable benefits. Standardizing demographic data reporting and integrating community-based participatory research methods can help foster inclusive research practices. This review was registered with prospective register of systematic reviews (PROSPERO), ID 296017. PERSPECTIVE: This systematic review investigates patient representation in pharmacological-based clinical trials for low back pain, LBP, the most prevalent pain condition worldwide. Improvements in reporting demographic data and recruiting diverse participant populations-across different racialized, gender and sexual minority, and age groups-will help clinical research generalizability and provide equitable benefits.