Racial and ethnic subgroup reporting in diabetes randomized controlled trials published from 2000 to 2020: A survey

BACKGROUND: It remained unknown about the status of and trends in racial/ethnic subgroup reporting in the diabetes trials over the past two decades. OBJECTIVES: In this survey, we aimed to evaluate the current state of and temporal trends in subgroup reporting by race/ethnicity regarding the effects of interventions in diabetes randomized controlled trials (RCTs) from year 2000-2020 and to explore the potential trial factors in relation to racial/ethnic subgroup reporting. METHODS: We searched electronic databases for eligible diabetes RCTs. The outcome was whether the trials had the event of racial/ethnic subgroup reporting regarding the intervention effects on trial primary outcomes. Poisson regression was used to assess the temporal trends in racial/ethnic subgroup reporting, and univariable logistic regression models were employed for evaluating trial factors related to racial/ethnic subgroup reporting. RESULTS: A total of 405 diabetes RCTs were eligible for inclusion. There were 26 (6.42%) trials with racial/ethnic subgroup reporting. A chronological trend towards increased rates of racial/ethnic subgroup reporting was observed; however, the trend was not statistically significant (p = 0.07). Advanced patients' age (Odds ratio [OR] = 2.92, 95% confidence interval [CI]: 1.24-6.88), follow-up duration (OR = 3.53, 95% CI: 1.13-11.00), and BIPOC (Black, Indigenous, and People of Colour) enrolment (OR = 2.39, 95% CI: 1.01-5.62) were found to positively relate with racial/ethnic subgroup reporting, while the industrial funding was associated with decreased reporting (OR = 0.43, 95% CI: 0.19-0.97). Less than one fourth of the trials with racial/ethnic subgroup reporting predefined the subgroup analysis. CONCLUSIONS: The majority of diabetes RCTs did not report intervention effects by racial/ethnic subgroup, which was not temporally improved over the past two decades. More efforts and strategies are needed to improve the racial/ethnic subgroup consideration and reporting in diabetes trials.