Assessing Ethnic Minority Representation in Fibromyalgia Clinical Trials: A Systematic Review of Recruitment Demographics

Abstract

The under-representation of non-White participants in Western countries in clinical research has received increased attention, due to recognized physiological differences between ethnic groups, which may affect the efficacy and optimal dosage of some treatments. This review assessed ethnic diversity in pharmaceutical trials for fibromyalgia, a poorly understood chronic pain disorder. We also investigated longitudinal change to non-White participant proportions in trials and non-White participants' likelihood to discontinue with fibromyalgia research between trial stages (retention). First, we identified relevant trials conducted in the United States and Canada between 2000 and 2022, by searching PubMed, Web of Science, Scopus, and the Cochrane Library databases. In trials conducted both across the United States and Canada, and exclusively within the United States, approximately 90% of participants were White. A longitudinal analysis also found no change in the proportion of non-White participants in trials conducted across the United States and Canada between 2000 and 2022. Finally, we found no significant differences in trial retention between White and non-White participants. This review highlights the low numbers of ethnic minorities in fibromyalgia trials conducted in the United States and Canada, with no change to these proportions over the past 22 years. Furthermore, non-White participants were not more likely to discontinue with the fibromyalgia research once they were recruited.

Keywords: ethnic minorities; fibromyalgia; longitudinal; non-White; pharmaceutical; retention; trials; underrepresentation.

Figure 1

Inclusion screening process for articles identified by our searches (left panels), and a breakdown of exclusion reasons (right panel).

Figure 2

Proportion and number of White participants enrolled in fibromyalgia pharmaceutical trials compared with all other ethnic groups. Data shown are from all studies identified in our searches that recruited new participants, where the proportion of White and non-White participants was reported. Data where these classifications were not reported in these studies for individual participants accounted for <0.1% of the participants across the studies, and are not displayed on the graph.

Figure 3

Proportion and number of White, Black, and other unspecified ethnic groups enrolled in fibromyalgia pharmaceutical trials conducted exclusively in the United States. Data from all identified United States trials where the numbers of White and Black participants were clearly specified. Data where these classifications were not reported in these studies for individual participants accounted for <0.1% of the participants across the studies, and are not displayed on the graph.

Figure 4

Longitudinal changes to the proportion of non-White participants in fibromyalgia trials. Pearson’s product-moment correlation coefficient found no significant changes in the proportion of non-White participants in fibromyalgia multi-centre trials between the start of 2000 to June 2022, (r = −0.13, [95% CI: −0.49, 0.26], p = 0.52, n = 27). p-value < 0.05 was considered significant.