Trials Informing Back Pain Guidelines Underreport Key Sociodemographic Data

Abstract

Introduction. Sociodemographic characteristics are related to low back pain (LBP) outcomes, therefore diverse representation is important when appraising clinical trials. We investigated the reporting of participant sociodemographic variables in trials informing the American College of Physicians (ACP) guidelines for the treatment of LBP. Methods. Clinical trials supporting recommended interventions in the ACP guidelines were reviewed for reporting of participant sociodemographic data. Results. Of 116 trials, 34 reported participant race and/or ethnicity. Education level, income level, and employment status were reported in 24, 10, and 31 trials, respectively; insurance coverage, marital status, and religion were reported in three, 16, and two trials, respectively. Two trials reported on duration or location of residence. Language comprehension was the most frequent exclusion criterion. Conclusions. Insufficient sociodemographic data exist in trials informing the ACP guidelines for the treatment of LBP. Investigators of LBP interventions should recruit diverse study participants and report comprehensive sociodemographic data.

Low back pain (LBP) is the single greatest cause of years lived with disability in many countries, and has increased in prevalence by 17.5% in the past decade.¹ Adverse LBP outcomes, including the transition from acute to chronic, disabling pain, are linked to social and economic factors including class, educational attainment, income inequality and poverty, and deprivation of essential resources.^2,3 There is increased risk of opioid prescriptions for people with self-reported LBP having only a primary school education, having difficulty meeting financial needs, and being widowed.⁴ Race appears to be a key moderating variable between social status and pain in patients with chronic LBP in the United States, where higher perceived social status is associated with significantly less LBP in White but not Black participants.⁵

Clinical practice guidelines are meant to optimize patient care by distilling systematic review evidence for therapies and comparing the benefits and harms of alternative options.⁶ However, when under-representation of sociodemographic minorities exists within study populations, effectiveness data may be misrepresented, limiting translation of interventions recommended by guidelines. Identifying sociodemographic variables, including race and ethnicity, of participants may provide information regarding the generalizability of study results.^7,8

Since sociodemographic characteristics of study samples likely influence treatment effect sizes and, subsequently, the appropriateness of guideline recommendations across diverse populations, we investigated the reporting of sociodemographic data in clinical trials informing the American College of Physicians (ACP) guidelines for the treatment of LBP.^2,7,9 These guidelines were endorsed by the American Academy of Family Physicians in 2017 and are assumed to have a strong influence on the clinical decision-making of primary care physicians in the United States.¹⁰

Methods

Clinical trials informing recommended interventions for LBP were identified by review of the ACP guidelines for noninvasive treatment of acute, subacute, and chronic LBP.^9,10 For each recommended intervention, citations for all clinical trials referenced and used to inform the ACP guideline recommendations were collected.

English-language articles on clinical trials cited as a supporting reference by the ACP were included in this study without any other eligibility criteria. In addition to citation information (first author, year, and country of study), the following sociodemographic variables were extracted from eligible studies and recorded into a Microsoft Excel table: race and ethnicity (White, Black/African American, Asian, American Indian/Alaska Native, Native Hawaiian/Pacific Islander, other/mixed race, and Hispanic/Latinx ethnicity), education level (less than high school, high school graduate, college graduate), income level/poverty category (individual income, household/family income), employment status (employed, unemployed, disabled or sick leave), insurance coverage (public, private, uninsured), and exclusion criteria that disqualified participants from enrolling in clinical trials (e.g., ability to read/write/speak English or the primary language in the country of study). Other relevant sociodemographic variables (e.g., marital status, religious faith, housing status) were also recorded in the Microsoft Excel table.

Data were extracted from eligible clinical trial studies and recorded independently by the primary investigator (TJW). For quality assurance, 10% of the eligible clinical trial studies were randomly selected, and data extraction was independently completed by a second investigator (PJB) for agreement. Disagreements on data extraction were resolved by discussion and refereed by three other investigators (JAG, ALS, JSW) when necessary.

Results

Citations were collected for 143 clinical trials supporting 20 interventions recommended by the ACP guidelines for the noninvasive treatment of acute, subacute, and chronic LBP. Out of the 143 clinical trials selected, a final count of 116 studies were included in this review. The study selection process is detailed in Figure 1. There was 94.8% agreement between raters when extracting data from the randomly selected clinical trials.

Overall, the number of studies providing baseline sociodemographic data is detailed in our supplementary table (Table S1): available from the authors upon request and shown in Figure 2. A total of 34 studies recorded the racial and/or ethnic background of study participants. Except for one study conducted in Egypt,¹¹ non-Hispanic White

Figure 1.

Study selection process.

Figure 2.

Reporting of sociodemographic data of study participants among clinical trials informing the American College of Physicians guideline for the treatment of low back pain.⁹⁴

was the most common ethnicity and race in all studies. Many studies did not specify the race or ethnicity of participants and only listed the percentage of White versus non-White participants. Furthermore, use of nonspecific terminology such as mixed or other without further specification was common among studies that did report on these variables.

Twenty-four trials reported the highest education level of participants. Because these trials originated from various countries with structurally diverse education systems, inconsistencies were observed in how education levels were described and categorized. Income levels were reported by a total of 10 studies, with observable differences in how they were measured. Authors categorized this variable according to individual income, household income, or whether participants earned more or less than $20,000/y ear. Employment status was described in 31 studies, including history of sick leave, receiving care on behalf of worker's compensation, or mention of work-related physical demand/exposure. Insurance coverage was noted in three trials—one of which required participants to have private insurance coverage as an inclusion criterion for trial enrollment.

Regarding other sociodemographic variables, marital status was reported in 16 studies, two trials documented religious faith as a social variable, and another trial recorded each participant's number of years lived in the country of study.¹² One study required that patients live within a one-hour drive from the trial location.¹³ The most frequent exclusion criterion regarding a sociodemographic variable was language comprehension and the ability to communicate and understand study procedures (n=21). One trial reported an exclusion criterion of greater than six months sick leave from work due to LBP.¹⁴

To see if certain recommended therapies had more representation than others, we stratified our data into drug and nondrug categories. There were 37 studies from our

Figure 3.

Drug trials reporting sociodemographic data of study participants.

Figure 4.

Nondrug trials reporting sociodemographic data of study participants.

final list used to support drug interventions, and 79 studies used to support nondrug interventions. Figures 3 and 4 display the representation of sociodemographic variables in these studies, respectively. Overall, nondrug trials reported more sociodemographic variables than drug trials.

Although not an aim, we observed that out of 116 eligible studies, 40 originated from the United States (U.S.) as determined by the institutional affiliation of the lead author.^15–54 The remaining 76 studies were written by investigators affiliated with non--U.S. institutions from 38 different countries.^{11–14,55–125}

Discussion

This study investigated the reporting of sociodemographic characteristics in clinical trials used to inform the ACP guidelines for the noninvasive treatment of LBP. Clinical trials supporting these guidelines overwhelmingly failed to report pertinent sociodemographic variables of study participants known to influence LBP prognosis and response to care. Although race and ethnicity were most frequently reported, only 29% of reviewed trials reported these variables (Table S1, available from authors upon request, Figure 2). Trials supporting nondrug therapies reported more sociodemographic data than drug trials (Figures 3, 4).

The routine absence of key sociodemographic data found in clinical trials assessed in the present study is alarming. This lack of reporting disallows for an acknowledgement of the prognostic influence of social determinants of health and misrepresents the strength and applicability of the recommendations across differing populations and clinical settings.⁷ The characteristics of individuals participating in clinical trials is an influential factor affecting the outcomes and generalizability of these studies.¹²⁶ Furthermore, during shared decision-making and informed consent processes, it is important that patients and clinicians are aware of and able to consider relevant findings associated with clinical trials.¹²⁶ To achieve a fully informed decision, it is essential that clinicians make patients aware of the clinical trial data used to inform their recommendations and acknowledge limitations in external validity.¹²⁶

Based on our findings, there is a clear need for improved reporting of participant sociodemographic characteristics in clinical trials for the treatment of LBP. According to the CONSORT 2010 guidelines for randomized trial design, researchers are encouraged to document baseline demographic and clinical characteristics of study participants entering a clinical trial, however, detailed information regarding which characteristics to include is not provided.¹²⁷ Researchers are encouraged to exhaustively report prognostic demographic and socioeconomic factors likely to influence outcomes in their baseline data collection, such as those analyzed in our review, and dedicate efforts to recruit a variety of subjects from diverse social conditions and lived experiences. Regarding race and ethnicity, these variables should be reported as separate and independent categories rather than a singular race/ethnicity group.⁸ To promote homogeneity between studies, quantifiable variables such as income or education level should be categorized according to standardized measurement parameters for feasibility of future comparative reviews. To our knowledge, no guidelines for the standardization of these measures exist. These improvements in trial design will enhance the reader's ability to appraise the validity of effectiveness data obtained from cohorts of varying backgrounds.

Given the infrequent reporting of baseline sociodemographic characteristics in clinical trials informing the ACP guidelines, it is challenging to translate these recommendations to diverse groups.^7,127 Of the clinical trials that did report these characteristics, most participants were non-Hispanic, White, and employed (Table S1, available from authors upon request). This apparent bias is especially problematic because it fails to acknowledge critical demographic and socioeconomic factors that influence response to care in marginalized patient populations. For instance, greater perceived social status is associated with White individuals experiencing less LBP severity and pain-related interference, whereas Black individuals experience increasing depressive symptoms and pain-related interference as they ascend the social ladder.^5,127 Over-representation of participants with favorable social conditions or less severe disease manifestations yields poor external validity and questionable replicability when extrapolated to those experiencing greater disease burden.¹²⁸

Although not an aim of our study, it is notable that most clinical trials informing ACP guidelines were conducted outside of the United States.^{11–14,55–125,128} It is unclear whether the U.S. Food and Drug Administration approved trials that studied drug effectiveness. Additionally, the nature and degree of social determinants of health are relative and depend on the availability and distribution of resources in a particular region. Therefore, participants enrolled in non-U.S. clinical trials are not affected by social influences of the same quality or magnitude as one might experience while living in the U.S.¹²⁹ Thus, the high proportion of non-U.S. studies further weakens the strength and applicability of these ACP guideline recommendations for diverse patient populations in the U.S. Further research investigating the effectiveness and applicability of noninvasive interventions for LBP recommended by the ACP, specifically among racial and ethnic minorities and low socioeconomic populations in the United States, is necessary.

There are two notable limitations with this study. First, only clinical trials informing the recommendations made by the ACP were evaluated.⁹ The ACP guidelines are one of many guidelines for LBP and may not account for all available trials informing clinical practice behaviors. However, considering the ACP is a flagship organization for primary care providers in the U.S., it is likely these guidelines are the most influential. Second, baseline sociodemographic characteristics collected in this study were incomplete and heterogeneous. Although it is not possible to discern from these data, failure to report sociodemographic data may reflect a failure in recruitment of minority group members and people who are medically underserved. However, it is possible a diverse participant base was represented, albeit, not reported in some of the trials we reviewed. Nonetheless, the lack of sociodemographic data presented highlights the need to be more cognizant of diverse participant recruitment and detailed demographic reporting in clinical trials on LBP treatment.

Conclusions

Clinical practice guidelines are helpful tools to facilitate shared decision-making and informed consent between clinicians and patients. The strength and applicability of the current ACP guidelines for the treatment of LBP across different populations are severely limited by an observed lack of detailed reporting of sociodemographic variables in referenced clinical trials. Thus, it is unknown if the supported interventions have equal, more, or less effectiveness for reducing LBP in people with diverse sociodemographic profiles or if novel treatments are needed. To explore this question, concerted efforts are needed to expand participant recruitment and to increase and standardize the reporting of sociodemographic characteristics in clinical trials assessing LBP treatment.

Conflict of Interest Statement

No funding was received for any component of this study. The authors declare no conflicts of interest. No portion of this paper has been presented or published elsewhere.