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Original Research Articles

An Analysis of the Inclusion of Women, Older Individuals, and Racial/Ethnic Minorities in Rehabilitation Clinical Trials

Silver, Julie K. MD; Flores, Laura E. BA; Mondriguez González, Antonio BS; Frontera, Walter R. MD, PhD

Author Information
American Journal of Physical Medicine & Rehabilitation: June 2021 - Volume 100 - Issue 6 - p 546-554
doi: 10.1097/PHM.0000000000001750

Abstract

What Is Known

  • Previous reports in other specialties, such as oncology, have reported disparities in the recruitment of women, racial and ethnic minority populations, and older people in clinical trials. In rehabilitation, there are well-documented patient care disparities particularly for racial and ethnic minorities.

What Is New

  • This study analyzed the representation of women, racial and ethnic minority populations, and older people in rehabilitation clinical trials and found that many studies do not adequately report demographic information and there are gaps in representation that should be addressed by investigators.

Although activism from underrepresented groups of people has been part of the foundation of both the specialty of physical medicine and rehabilitation and the formation of ClinicalTrials.gov, it is well documented that medical research has not equitably included women, older individuals, racial/ethnic minorities, or persons with disabilities1–3—potentially leaving these groups at a disadvantage regarding treatment recommendations that will be most beneficial to them. The National Institutes of Health Revitalization Act of 1993 mandated the appropriate inclusion of women and racial/ethnic minority participants in clinical trials4; however, more than two decades later, their numbers remain persistently low.5 For example, a study by Chen et al.5 found that less than 2% of the National Cancer Institute’s clinical trials focus on any racial/ethnic minority population as their primary emphasis, and the percentage of authors who reported their study sample by race/ethnicity ranged from 1.5% to 58%. The SARS CoV-2 (COVID-19) pandemic and search for effective vaccines has highlighted disparities in race/ethnicity related to infection rates, serious morbidity, and mortality.6–8 We conducted a study with colleagues that examined vaccine clinical trials from July 2011 to June 2020 and found that racial and ethnic minorities were underrepresented and female adults were overrepresented.2 As such, there has been a growing concern about9,10 and increased effort11 to include racial/ethnic minorities in the vaccine trials and to address racial/ethnic minorities’ rehabilitation needs as they relate to postinfection sequelae.12

Older people continue to be left out of clinical trials or have low representation.13–15 Similar to the previously mentioned issue of race/ethnicity in cancer trials, oncology has well-documented disparities in the inclusion of older individuals in cancer studies.15 For example, a recent Institute of Medicine Report described a critical need for more research in older adults with cancer and highlighted the fact that most people who get cancer are older, and this demographic is increasing as people live longer.16 Also similar to the previously mentioned national concern for the inclusion of racial/ethnic minority participants in COVID-19 vaccine trials, concerns have been raised about the inclusion of older adults in the ongoing vaccine trials.17

In contrast to our previously mentioned study on vaccine clinical trials where women were found to be overrepresented as participants,2 there is a large body of literature demonstrating that women are often underrepresented in clinical trials.1,3 The inclusion of women in clinical trials is critical as they differ from men in anatomy, vascular biology and risk factors, immunity, neuroprotective factors, coagulation, hormonal profiles, reproduction, lifestyle factors, and societal roles.18 For instance, stroke is the second largest cause of disability-adjusted life-years lost worldwide (behind ischemic heart disease) and a leading cause of death worldwide, with both morbidity and mortality disproportionately affecting women.18 Notably, the inclusion of women in trials may actually help identify why men sometimes have worse outcomes—thereby focusing treatment interventions to improve outcomes for men. For example, a recent study in a diverse cohort of acute stroke patients with COVID-19 disease was aimed at determining the role of sex on outcomes and found that men had a higher mortality, more in-hospital complications, increased incidence of ischemic stroke, and were less likely to be discharged home.19 These sex-related differences in outcomes could only be elucidated because women were included in the study, and the finding will help direct future research that may improve outcomes for men infected with COVID-19. In short, the inclusion of female participants in clinical trials is not only good science that may improve treatments for women but also including women may help men have better outcomes, too.

The National Institutes of Health requires investigators to describe their strategy for the equitable inclusion of women and minorities in their research plan and report on participant race and ethnicity in yearly progress reports and has recently launched an inclusion across the lifespan policy aimed at the inclusion of older individuals.20,21 Although there has been some progress regarding equitable inclusion, nevertheless, ethical issues and bias are deeply entrenched in clinical trials research.22 Heart disease research, including cardiac rehabilitation, has demonstrated similar issues.23

In this study, we hypothesized that in rehabilitation clinical trials, three groups of people would be underrepresented: (1) women; (2) people 65 yrs or older; and (3) individuals who identify with a racial and/or ethnic minority group. To test our hypothesis, we examined all of the rehabilitation clinical trials reported on ClinicalTrials.gov that were conducted on adults over the past decade. Notably, for the purposes of this study, the terms that woman/women refer to female participants as ClinicalTrials.gov categories focus on sex rather than the gender spectrum.

METHODS

Study Identification

On April 13, 2020, the term “rehabilitation” was used to identify clinical trials that were registered within ClinicalTrials.gov. We selected studies that started within the past decade (January 1, 2011–January 1, 2020) and focused on rehabilitation interventions in adults 18 yrs and older. To be included, studies needed to be categorized by the study site as completed and with available results.

Those studies testing integrative or complementary and alternative medicine therapies and studies that focused solely on mental health (e.g., depression) were excluded. Also excluded were studies that were completed but no results were available or studies that were categorized by the study site as not yet recruiting, recruiting, enrolling by invitation, active not recruiting, suspended, terminated, withdrawn, or unknown. Of the 115 studies that resulted from the search, seven were excluded for reasons listed previously.

Data Collection

We collected demographic information including sex, age, and race/ethnicity. Race was standardized using the National Institutes of Health and Office of Management and Budget definitions (White, Black or African American, Asian, Hawaiian or Pacific Islander, American Indian or Alaskan Native, one or more races, and other, missing or unknown), whereas ethnicity was classified separately as Hispanic or Latino.24

Selected studies were categorized by primary diagnostic group and included amputation, cancer, musculoskeletal medicine (e.g., nonspine), neurodegenerative disorders (e.g., amyotrophic lateral sclerosis, multiple sclerosis, Parkinson, polio), nontraumatic brain injury (e.g., memory disorders, cognitive impairment, Alzheimer, and other), stroke, spinal cord injury (SCI), spine, sports medicine, traumatic brain injury (TBI), cardiac (e.g., coronary artery disease), pulmonary, sensory organs (e.g., visual, vestibular, hearing), speech and language, and other (e.g., diabetes, peripheral artery disease, spastic hemiparesis).

We classified the primary outcome as identified by the outcomes listed in the ClinicalTrials.gov database. The primary outcomes were further categorized into International Classification of Functioning, Disability and Health categories.25 Each outcome was searched in the Shirley Ryan Ability Lab website and categorized according to the International Classification of Functioning, Disability and Health category or categories listed on the site.25 For those unable to be classified, consensus of the authors was used to determine International Classification of Functioning, Disability and Health categories. The month and year of the start and conclusion of the study were noted. We also collected the primary country of origin. This review did not involve human subjects, and the information collected is publicly available; therefore, institutional review board approval was not required. The study conforms to all Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines and reports the required information accordingly (see Supplemental Checklist, Supplemental Digital Content 1, https://links.lww.com/PHM/B275).

Statistical Analysis

For trials reporting sex, age, race, or ethnicity information as percentages, integer counts of participants were computed by multiplying the percentage in each group by the total number of participants analyzed. These counts were then rounded to the nearest integer. To draw population comparisons with the US (United States) census, only US-based trials (69%) were included in the analyses for race, ethnicity, and sex. For comparisons with the US population, data from the 2011 and 2018 American Community Surveys (i.e., census) were used.26,27 This approach for comparison has been used previously to analyze vaccine clinical trials.2 Additional diagnosis-specific comparisons were made for SCI, TBI, and stroke using available prevalence data.28–31 We were not able to make similar comparisons with other diagnostic categories (such as cardiac and musculoskeletal) because of the heterogeneity of the categories. All analyses were completed using SPSS Statistics Version 25.0 (IBM, Armonk, NY).

RESULTS

Of the 108 studies identified, a majority were based in the US (69%), followed by Italy (6%), Canada (5%), and Brazil (5%; Fig. 1). Diagnostic grouping revealed stroke as the most common diagnosis, followed by musculoskeletal conditions (Table 1). The most common primary intervention group was technology, followed by physical activity/exercise (Table 2).

F1
FIGURE 1:
Registered rehabilitation clinical trials by country (N = 108). The map demonstrates regional clinical trials by country.
TABLE 1 - Diagnostic groups among registered rehabilitation trials
N = 108 %
Stroke 32 30
Musculoskeletal medicine 21 19
Neurodegenerative disorders (e.g., amyotrophic lateral sclerosis, multiple sclerosis, Parkinson) 9 8
Sensory organs (vestibular, visual, auditory) 9 8
Cardiac 7 7
Nontraumatic brain injury (e.g., memory disorders, cognitive impairment, Alzheimer, and other) 7 7
Other a 5 5
Traumatic brain injury 5 5
Spinal cord injury 4 4
Amputation 3 3
Cancer rehabilitation 3 3
Pulmonary 3 3
The diagnostic groups in this table demonstrate the proportion of rehabilitation trials registered at ClinicalTrials.gov.
a“Other” includes complex patients in rehabilitation phase, spastic hemiparesis, use of power wheelchairs and power seat functions, and neuropsychological.

TABLE 2 - Primary intervention group of registered rehabilitation trials
N = 108 %
Technology 44 41
Physical activity/exercise 25 23
Behavioral 12 11
Physical modality 5 5
Other a 5 5
Education 4 4
Cognitive/executive function training 4 4
Therapy (physical, occupational, speech) 4 4
Medication (injectable) 3 3
Multimodal 2 2
The intervention groups in this table demonstrate the proportion of rehabilitation trials registered at ClinicalTrials.gov.
a“Other” includes vocational rehabilitation, medication (oral), other (neuropsychological), animal therapy, and hypoxia.

When primary outcomes from all trials were classified by the International Classification of Functioning, Disability and Health, 42% of studies were categorized as body function and structures, 32% as activity, 10% as participation, and 1% as environmental factors.

Of the 108 total studies, 107 provided demographic information pertaining to the inclusion of female participants. Of the US-based trials reporting sex data (n = 72), 96% included at least one female participant in their trial. Among specific diagnostic groups in US-based clinical trials, the percentage of female participants ranged from 5% to 73%, in SCI trials and neurodegenerative disorders trials, respectively (Fig. 2). When compared with the prevalence within SCI, TBI, and stroke, female participants remained underrepresented in all groups. Although female adults make up 22% of SCI diagnoses, 26% of TBI diagnoses, and 57% of stroke diagnosis, they only make up 5, 12, and 42% of clinical trial participants in each category, respectively (Fig. 3).

F2
FIGURE 2:
Female adult participants in US-based rehabilitation trials. This figure demonstrates the percentage of female adult participants in US-based rehabilitation trials by diagnostic grouping. The number in parentheses for each diagnostic group represents the total number of participants.
F3
FIGURE 3:
Sex representation in clinical trials and diagnostic groups. This figure demonstrates a comparison of sex representation in clinical trials and specific diagnostic groups. For additional comparisons, the percentages of adult women in the 2011 (2018) US Census are represented by the dotted line.

One hundred seven studies, including both US and international trials, reported age information. Age information was reported nonspecifically by ClinicalTrials.gov, with some trials providing a percentage of persons 65 yrs and older, some trials reporting mean and standard deviation, and some providing only a range of ages enrolled. Therefore, it was not possible to determine the absolute number of older persons participating in the trials. Of those reporting age (73/107 reporting age were based in the US), 76% of trials included at least one person 65 yrs and older. Among specific diagnostic groups, there was a wide range (0%–100%) regarding inclusion of persons 65 yrs and older, with zero SCI trials including those 65 yrs and older and 100% of cardiac trials including those 65 yrs and older. Twenty percent of TBI trials and 62% of musculoskeletal trials included those 65 yrs and older.

Only 40.1% (44) and 26.9% (29) of US-based trials reported race and ethnicity, respectively. Among all clinical trials based in the US that included race information, 70% of participants were White, followed by 20% Black or African American and 1% Asian. Few trials (n = 23) included a small number of Hispanic or Latino participants. Enrollment among musculoskeletal trials in the US included a majority of White participants (83%), followed by Black or African American (14%) and Asian (1%; Fig. 4). Among all US-based clinical trials and diagnostic subgroups reporting ethnicity (stroke, musculoskeletal, cardiac, SCI, and TBI), each included fewer than 10% Hispanic or Latino participants (Fig. 4). This is in contrast to the US population, which is 18.5% Hispanic or Latino (2018).

F4
FIGURE 4:
Racial and ethnic makeup of US-based registered rehabilitation clinical trials. This figure represents the percentage of participants in each race or ethnicity group overall and within the individual diagnostic categories. The first bar in each section represents all rehabilitation trials, and this is followed by five individual diagnostic categories for each race and ethnicity.

When additional diagnosis specific comparisons were made for SCI and TBI, some disparities diminished and others widened. For example, although 24% of those with an SCI are Black or African American, 29% of those in SCI registered rehabilitation trials were Black or African American.30 A similar finding was observed with TBI, with Black or African Americans overrepresented (59%) compared with the prevalence (18%) of TBI diagnoses among this group (Fig. 5). The opposite is true of White and Asian populations, who are underrepresented in SCI and TBI clinical trials (Fig. 5).

F5
FIGURE 5:
Racial representation among clinical trials and specific diagnostic groups. This figure demonstrates a comparison of representation by racial group in clinical trials and specific diagnostic groups. For additional comparisons, the 2011 (2018) US Census percentage of White, Black or African American, and Asian persons is represented by the dotted line.

Hispanic or Latino participants were severely underrepresented when compared with diagnostic specific rates. Thirteen percent of those with an SCI are Hispanic or Latino, while they made up 0% of clinical trial SCI participants, and 11% of those with a TBI are Hispanic or Latino, while they made up 5% of SCI clinical trial participants (Fig. 6).

F6
FIGURE 6:
Ethnic representation among clinical trials and specific diagnostic groups. This figure demonstrates a comparison of Hispanic or Latino participants in clinical trials and specific diagnostic groups. For additional comparisons, the 2011 (2018) US Census percentage of Hispanic or Latino adults is represented by the dotted line.

DISCUSSION

We hypothesized that three groups of people—women, people 65 yrs and older, and individuals who identify with racial/ethnic minority groups—would be underrepresented in rehabilitation clinical trials. In the present study, the most important findings are that when compared with the US census data and/or prevalence of conditions in SCI and TBI, (1) women are underrepresented overall and in every diagnostic group except musculoskeletal medicine and neurodegenerative disorders; (2) people 65 yrs and older are included from 0% to 100% depending on the diagnostic category with SCI studies reporting 0% inclusion and cardiac trials reporting 100% inclusion; (3) Hispanic or Latino and Asian participants are underrepresented overall and in each diagnostic category; and (4) Black or African American participants are overrepresented overall and in every category with the exception of cardiac studies in which they are underrepresented. Nearly all studies reported sex and age, whereas slightly less than half of the studies reported race/ethnicity. Another important finding in this study was that fewer than half of US-based rehabilitation trials report any race and/or ethnicity data. Despite this, of the studies where there were data reported, our findings support our hypotheses that the three examined groups of people are underrepresented as study participants in rehabilitation medicine clinical trials. To our knowledge, this is the first study that investigates the inclusion of women, age distribution, and participation of racial/ethnic groups in rehabilitation clinical trials.

Inclusion of Women

In our study on vaccine clinical trials, we found that female adults were overrepresented as participants2; however, in general, our finding in this rehabilitation study that women were underrepresented is more consistent with previous literature that demonstrates lower than expected representation in clinical research.1,3 Although women were included in 96% of the trials that we examined, this is not an accurate representation of their participation, because they comprised only 27% of the total participants. In comparison, women comprise approximately 51% of the US population. Thus, their representation in rehabilitation clinical trials is roughly half of what would be anticipated based on population density.

Of particular interest is the evaluation of participation by diagnostic category. For example, in stroke trials, women had the most representation (42%), but this was still less than their representation in society (51%). To put this finding in context, premenopausal women have a lower risk of stroke compared with young adult men; however, most strokes occur in older people, and after menopause, the trend reverses with women having a stroke incidence double that of men.32 Older women have not only a greater prevalence of stroke but also worse outcomes.32 However, most of the stroke trials that we examined did not include a number of women that would be equivalent to the number of women stroke survivors (Fig. 3). As women age, proposed reasons for the sex-related discrepancy in incidence have included issues, such as loss of estrogen, poorly controlled hypertension, and atrial fibrillation.32 A systematic review that assessed sex and prehospital delays in initial stroke care found no difference in most studies (n = 15), but four of the studies, from Asian-Pacific countries and the US, demonstrated that women had significantly longer prehospital delays and that older age, minority race/ethnicity (Black and Mexican American), and underuse of emergency medical services were associated with their prolonged prehospital delays.33

In the diagnostic category of SCI, women were least represented as participants (5%), yet they comprise more than 20% of new SCI cases in the US (Fig. 3).28 Interestingly, women were overrepresented in one category—neurodegenerative diseases (73%). Although this category includes a small number of trials (n = 9) and a mix of six diagnoses, the representation of women in the neurodegenerative category may be influenced by the inclusion of four trials in multiple sclerosis. Multiple sclerosis impacts women much more frequently than men (female/male ratio, 2.8),34 potentially accounting for the overrepresentation of women in this category (Fig. 2).35

Inclusion of Older People

In this study, we found that age information in ClinicalTrials.gov was not reported in a consistent manner. Therefore, the precise number of participants in the 65 yrs and older age group cannot be calculated. This is an important observation and potential weakness in clinical trials design because the number of people in this age group has increased significantly in the last century and it has been projected that by the year 2050, approximately 21% of the world’s population will be in this age group.34 In some countries, this may be as high as 40%. Furthermore, at the end of 2017, the US National Institutes of Health established a policy for the inclusion in clinical trials of subjects across the lifespan.20

We found that important differences in the reporting/inclusion of older adults were noted depending on the diagnostic group. This is relevant because the incidence of many health conditions that benefit from rehabilitation interventions increases with age. Furthermore, because many younger patients survive the acute injury, survivors are aging with permanent impairments and could benefit from rehabilitation interventions before and after reaching advanced adult age. In the present study, although almost all stroke and cardiac trials included participants 65 yrs and older, none of the trials of SCI and only 20% of the trials of TBI did. In the US, the incidence of traumatic SCI has been reported to decline in younger groups but increase significantly in older individuals, and falls are a major contributing factor.36 The high incidence of falls in older adults is also a cause of an increased incidence of TBI in elderly men and women.36

Inclusion of Racial and Ethnic Minority Participants

Approximately 72% of adults in the US identify as White, and in our study, we found that they are slightly underrepresented overall (70%) in US-based rehabilitation clinical trials.26,27 In the analysis of race and ethnicity among diagnostic groupings, again compared with US census data, Hispanic or Latino and Asian participants were underrepresented overall and in each diagnostic category. On the other hand, Black or African American participants were overrepresented overall and in every category with the exception of cardiac studies in which they were underrepresented (Fig. 4).

Comparisons with population data may underestimate or overestimate disparities, depending on the representation of people who identify as racial/ethnic minorities within a diagnostic category. For example, in the US, there are more than 17,000 individuals who experience acute, traumatic SCI every year, with persons of Hispanic origin making up 11% of all SCI.27,37 Thus, the low representation of Hispanic or Latino participants in SCI clinical trials (5%) is even more impressive when considering the high incidence of SCI among Hispanic or Latino people (Fig. 6).

Numerous studies have demonstrated disparities in the receipt of rehabilitation services as well as worse health and functional outcomes for Black or African American and Hispanic or Latino patients compared with White patients.12,38 For instance, among patients with SCI being Black or African American was found to be a significant independent risk factor for skin pressure injuries (odds ratio = 1.7 compared with non-Black or African American patients).39,40 Black or African American individuals with SCI are 5 times more likely to have recurrent urinary tract infections due to neurogenic bladder compared with similarly injured White individuals.39,40 Freburger et al.41 analyzed the discharge disposition of 64,065 patients who survived their acute inpatient stay after a hip fracture and found that Hispanic individuals were less likely to receive postacute institutional care (skilled nursing facility or acute inpatient rehab hospital) in comparison with White patients (odds ratio = 0.7). Racial and ethnic minority populations are disproportionately affected by COVID-19, and future research will likely document disparities in rehabilitation care and outcomes.12 These studies suggest that representativeness in rehabilitation clinical trials is an important goal if we want to achieve similar outcomes in all racial/ethnic groups.

Although often overlooked, an important consideration regarding the inclusion of various groups in clinical trials involves overcoming objections that they may have if/when an intervention is approved and/or routinely recommended. For example, many Black or African American people have a long-standing and well-founded distrust of medical science that is based on their historic and modern mistreatment (e.g., Tuskegee syphilis study, maternal/infant mortality rates). Although Black or African American minorities are more likely to contract COVID-19 and have worse outcomes, reports suggest that for many, their legitimate distrust will result in opting out of getting vaccinated.9,10

Regulatory Framework

The 21st Century Cares Act that was passed in 2016 requires investigators to include specific groups in National Institutes of Health–Defined Phase III Clinical Trials. Investigators must also submit their results to ClinicalTrials.gov after conducting analyses based on race, ethnicity, and sex/gender. These analyses must include an unbiased evaluation, with appropriate randomization, documentation of differing outcomes or measures, and a comparison of intervention effects based on sex/gender, race, and ethnicity. The new requirements were applied to all new competing grants awarded from December 2017 onward.21 In addition, in 2016, the National Institutes of Health updated its existing 1998 policy regarding the inclusion of children in research, to also include older individuals. This shift emphasized the inclusion of subjects “across the lifespan.” The policy requires investigators who are excluding children or older individuals to provide a valid explanation.20

Notably, a focus on the inclusion of underrepresented groups in clinical trials is often left out of or minimized in discussions and recommendations about advancing the science of rehabilitation medicine. For example, an excellent report titled “Medical rehabilitation: guidelines to advance the field with high-impact clinical trials” was published by a group of subject matter experts convened by the National Center for Medical Rehabilitation Research with the aim of the workshop “to examine rail design and conduct considerations viewed by the panel as essential to the success and ultimate effect of clinical trials in medical rehabilitation, and to summarize recommendations to the researcher seeking to lead such trials.”42 However, beyond a brief mention of nonmodifiable input factors, such as sex, race/ethnicity, and age, may affect response heterogeneity, the report did not provide any other historical context or future recommendations. In contrast, in response to the Institute of Medicine report “Delivering high-quality cancer care: charting a new course for a system in crisis” that highlighted the need to improve the evidence base for treating older adults with cancer,16 the American Society of Clinical Oncology convened a group of subject matter experts and released a policy statement focusing on the inclusion of older individuals in cancer clinical trials.14 The American Society of Clinical Oncology’s policy statement is aimed at improving the scientific evidence base in older adults with cancer and recommends to14:

  1. Use clinical trials to improve the evidence base for treatment.
  2. Leverage research designs and infrastructure for generating evidence.
  3. Increase US Food and Drug Administration authority to incentivize and require research involving older adults with cancer.
  4. Increase clinicians’ recruitment of older adults with cancer to clinical trials.
  5. Use journal policies to improve researchers’ reporting on the age distribution and health risk profiles of research participants.

Rehabilitation clinical trials including but not limited to those evaluating the effectiveness of technologies, such as robotic devices and exercise programs, should include older individuals, women, and people who identify with minority racial/ethnic groups.

Study Limitations

This study has limitations inherent to the use of the ClinicalTrials.gov database. Categories listed on the site, such as sex and race, do not account for the spectrum of sex and race, respectively. Trial investigators may not enter information about their studies in ClinicalTrials.gov in a consistent way, particularly when it comes to demographic information about trial participants. Race and ethnicity reporting were frequently reported using the National Institutes of Health and Office of Management and Budget standards; however, in some cases, investigators used “customized” race reporting. In these cases, subgroups had to be combined (e.g., East Asian and Central/South Asian combined to “Asian”) to fit the standard reporting. ClinicalTrials.gov does not have a standard for age reporting, resulting in difficulty addressing age disparities. Age was reported inconsistently by category, mean, range, and/or percentage of participants 65 yrs and older. In some studies, the investigators were not specific about their primary outcomes in which case the authors used the available description of the study to deduce the most likely primary outcomes. Finally, the authors are not able to account for inaccuracies in the ClinicalTrials.gov database. These limitations offer an opportunity to identify weaknesses in the ClinicalTrials.gov database for future investigations.

CONCLUSIONS

We examined clinical trials in rehabilitation medicine over the past decade and found that women, older individuals, and racial/ethnic minorities were generally underrepresented. Notable exceptions include the overrepresentation of Black or African American participants in all categories except cardiac studies. Although we did not study causality, it is known that Black or African American people have a higher incidence of rehabilitation conditions, such as SCI and stroke. We also found that there are many gaps in the reporting of sex, race/ethnicity, and age for study participants, with age being a particularly challenging issue on ClinicalTrials.gov. Our findings suggest that rehabilitation medicine should focus on improving the inclusion of underrepresented populations. Furthermore, the reporting guidelines of ClinicalTrials.gov may require revision and modification, most notably regarding age.

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Keywords:

Physical Medicine and Rehabilitation; Ethnic Groups; Aged; Clinical Trial; Disparities

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