Ethnoracial representation in hidradenitis suppurativa clinical trials

Hidradenitis suppurativa (HS) is an inflammatory skin disorder characterized by recurring painful and suppurating lesions, with the disease disproportionately affecting black populations in the United States. Ethnoracial representation in clinical trials is vital to ensuring results are generalizable. The purpose of this study is to examine whether ethnic or racial disparities exist in HS clinical trials. The US National Library of Medicine clinical trials database (clinicaltrials.gov) was queried to identify HS clinical trials. Trials that did not present ethnic or racial data on either the website or publication were not considered. A total of 57 HS trials were identified. Of these, 23 trials, containing 2530 patients, included racial or ethnic data (Table 1). White patients made up 76.1% (1435/1886) of the study population, followed by Blacks or African Americans (13.7% (238/1732)), Hispanics or Latinos (7.2% (20/279), Asians (2.6% (26/1016)), American Indians or Alaska Natives (1.3% (14/1051)), and Native Hawaiians or Other Pacific Islanders (0.4% (4/926)). Our results establish a significant lack of minority ethnoracial representation in HS clinical trials. Since HS prevalence is highest among Blacks or African Americans, it is imperative that future clinical trials are conducted with a larger proportion of this population. Furthermore, clinical trials that did not report racial or ethnic information were conducted in countries with predominantly White populations, which likely skewed the results of this study and caused underreporting of these patients.


Introduction
Hidradenitis suppurativa (HS) is a debilitating inflammatory skin disorder characterized by recurring painful nodules, abscesses, and suppurative sinus tracts [1]. The typical age of onset is between 20 and 40 years old, with women affected three times as often as men [2]. The global prevalence of HS is estimated to be in range of 0.00033-4.10%, with more recent studies reporting a prevalence between 0.7 and 1.2% [2,3].
Significant advancements in the treatment of HS show promising results in clinical trials.
However, our understanding of HS outcomes in racial and ethnic minorities is severely lacking. Analyses of demographic data in clinical trials involving other dermatologic conditions such as psoriasis and atopic dermatitis have previously illuminated a significant underrepresentation of racial and ethnic minorities. The underrepresentation of minorities in clinical trials presents a major problem as data from various retrospective analyses suggest that the prevalence of HS in the black population is disproportionately elevated [4][5][6]. Diverse racial and ethnic representation in clinical trials is vital to ensure results are generalizable. Previous studies have focused on phase II and III trials, as well as only including trials examining biologic treatments [7]. The purpose of this study was to examine whether racial or ethnic disparities exist in phase I-IV HS clinical trials examining all available treatments.

Methods
The US National Library of Medicine clinical trials database (clinicaltrials.gov) was queried on July 27, 2022 to identify phase I to IV clinical trials in HS. We searched the term "hidradenitis suppurativa" and considered all clinical trials that were completed before the date of our search. For trials that did not present their results on the website and were linked to a publication, the publication was used instead. Trials that did not present racial or ethnic data on either the website or publication were removed from consideration. Similar to a publication examining psoriasis clinical trials, the denominator for each ethnoracial group was determined using only the studies that included that specific ethnoracial group as a potential category [8].

Results
A total of 57 trials were identified on clinicaltrials.gov. After removing all studies that did not include racial or ethnic data, 23 trials remained, containing 2530 patients (

Discussion
The results from our analysis are concerning as the proportion of minority populations in the clinical trials studied was low.  [9], it is imperative that future clinical trials are conducted with a larger proportion of these populations so that results will be more clinically relevant and generalizable. The association between HS and patients with skin of color is complicated and likely multifactorial. It has been suggested that these patients are at greater risk of HS morbidity due to a higher prevalence of depression and metabolic syndrome, low socioeconomic status, and limited access to medical care [10]. Additionally, since African American HS patients tend to seek care later with more disease burden and severity than their White counterparts, it is vital that trial data be readily available in these populations, as systemic therapies are indicated for patients with moderate to severe disease.
Furthermore, a contributing factor to the ethnoracial disparity found in clinical trials is the distribution of clinical trial site locations [7]. A significant number of HS clinical trials were conducted in countries with lower racial diversity, such as Denmark, Germany, Netherlands, Sweden, and Greece. Furthermore, the clinical trials that did not report racial or ethnic information were notably conducted in countries with predominantly white populations, likely skewing our results and causing underreporting of White patients. A potential solution to this issue is to ensure that clinical trials include locations with a higher percentage of minority populations, particularly the Black population. It is also vital that increased efforts are made to recruit diverse patient populations to participate in the HS clinical trials.
Due to the fact that clinical trials conducted in multiple countries did not explicitly specify how many subjects were recruited from each individual country, it was not possible to accurately conduct a subgroup analysis of racial composition of trials conducted at USA versus non-USA sites. For example, of the 18 studies involving sites in the United States, 8 studies also involved sites outside of the United States with no racial breakdown. This may represent a confounding variable, as there are significantly fewer non-white patients with HS in Europe when compared to the United States. Nevertheless, the overall racial diversity in HS trials remains low, suggesting the importance of including more sites where racial diversity exists.
Race and ethnicity represent potential predictors for increased disease severity. The impact of HS on quality of life, mental health, depression, and work productivity are significant and are unfortunately impacting the relatively more vulnerable patient populations. Clinicians need access to data regarding the efficacy of treatments in diverse populations to make well-informed decisions. This study highlights the need for an escalation of efforts to increase ethnoracial diversity in HS clinical trials and increase diversity recruitment.
Author contributions KE, MD, and MH drafted and wrote the main manuscript text. RS, JJ, SY, MC, and EB were involved in critical revision of the manuscript. TB and WL were involved in conceptualization and planning of the manuscript text as well as critical revision of the manuscript.

Data availability statement
The data that support the findings of this study are available at clini caltr ials. gov.