Abstract
Background
Degenerative lumbar disc disease (DLDD) can contribute to substantial low back pain and radicular leg pain. Emerging evidence suggests that racial and ethnic disparities in DLDD care could impact clinical outcomes, yet these trends remain largely unexplored. This study investigates differences in health literacy, access to care, and healthcare utilization among patients with DLDD using the All of Us (AoU) Research Program.
Methods
Adults diagnosed with DLDD were identified from the AoU database using ICD-9 and ICD-10 diagnostic codes. Participants were stratified by race and ethnicity into White, Black, Hispanic, and Other. Demographics, socioeconomic status, health literacy (BRIEF score), healthcare access, and treatment utilization across racial and ethnic groups were compared across cohorts using chi-square analyses. Multivariate logistic regressions evaluated these outcomes while adjusting for demographic and socioeconomic status.
Results
In total, 30,775 participants with DLDD were identified. Most participants were 65+ years (62.8%) and female (65.3%), with 74.0% self-identifying as White, 10.7% as Black, 8.1% as Hispanic, and 7.2% as Other. Compared to Whites, Black and Hispanic participants were significantly more likely to report limited health literacy (White = 15.3%, Black = 22.2%, Hispanic = 28.1%, Other = 21.3%, P < 0.001). In addition, they were more likely to be denied insurance coverage (9.7%, 10.5%, 14.5%, 13.8%) and report difficulty affording care, including prescription medications (11.5%, 20.9%, 19.0%, 18.9%) and follow-up visits (6.2%, 10.0%, 10.7%, 9.3%) (all P < 0.001). Finally, Black participants, in particular, were more likely to receive nonoperative treatments such as physical therapy (25.7%, 28.2%, 23.1%, 25.9%), steroid injections (14.4%, 16.7%, 12.8%, 12.4%), and opioids (49.1%, 53.4%, 42.5%, 48.3%) compared to White participants (all P < 0.001). Many of these disparities persisted in multivariate models after adjusting for demographic and socioeconomic covariates.
Conclusion
Disparities in DLDD are multifactorial, reflecting the intersection of age, sex, race/ethnicity, comorbidities, and social determinants of health. Despite most participants being Medicare-eligible, minority groups continued to report access and affordability barriers, suggesting the role of underinsurance and coverage gaps. These findings underscore the need for targeted interventions to improve access, promote education, and ensure equitable treatment of DLDD across minority populations.
Keywords
Introduction
Degenerative lumbar disc disease (DLDD) is one of the leading causes of chronic low back pain and disability worldwide. It is characterized by reduced disc height, facet joint arthropathy, and spinal instability, which can subsequently contribute to neurologic compression. Although the natural history and biomechanical underpinnings of DLDD have been well described, less attention has been directed toward racial and ethnic disparities in its clinical manifestation, management, and outcomes.
Emerging evidence suggests that the burden of DLDD does not affect all populations equally. Age is a well-established determinant, with older adults exhibiting more radiographic degeneration and higher symptom burden.1-3 Sex-based differences have also been observed, with women reporting greater pain intensity and functional impairment despite comparable imaging findings. 4 Beyond biological variation, however, structural inequities, including race, ethnicity, socioeconomic status, and healthcare access, may play a critical role in shaping the management of DLDD. Several studies have demonstrated that racial and ethnic minorities face persistent barriers to care, including lower health literacy, fewer financial resources, and reduced access to specialty services.5-8 Comorbidities more prevalent in underserved populations, such as diabetes, hypertension, and cardiovascular disease, have been linked to accelerated disc degeneration and poorer postoperative outcomes.5,9-11 Non-White race, in itself, has also been independently associated with greater disc disease severity, even after controlling for medical and lifestyle risk factors.5-8,12
Despite these observations, few studies have systematically quantified disparities in DLDD using nationally representative data sources. The All of Us (AoU) Research Program offers an opportunity to examine population-level disparities in health literacy, healthcare access, and treatment utilization among patients with DLDD. 13 In this study, we aimed to characterize healthcare disparities in DLDD using the AoU database, with particular emphasis on racial and ethnic differences in health literacy, access, and utilization of care. We hypothesized that non-White individuals would demonstrate reduced health literacy, greater access-related challenges, and underutilization of surgical treatments compared to their White counterparts, even after controlling for demographic and socioeconomic covariates.
Methods
Study Design
The AoU Research Program is a National Institutes of Health (NIH)-funded initiative that collects health information on the broader United States population. Participants either enroll directly from the AoU website or through invitations from partner health care organizations. Enrollees provide access to their EHR, complete sociodemographic and health-related surveys, sync their Fitbit device data, and supply their physical measurements and biological samples. A retrospective cross-sectional analysis was conducted using the All of Us Research Program database. Institutional review board approval was waived since the dataset has been deidentified for public access.
Study Population
Adults over the age of 18 years with a diagnosis of degenerative lumbar disc disease were identified using International Classification of Diseases (ICD)-9
Outcomes
Primary outcomes included (1) health literacy as assessed on the Overall Health survey, (2) healthcare access (cost-related delays, transportation issues) as assessed on the Health Care Access & Utilization survey, and (3) DLDD treatment utilization (physical therapy, pharmacologic interventions, surgery) as identified using ICD-9 and ICD-10 codes.
For health literacy, a modified Brief Health Literacy Screening Tool (known as BRIEF) score was calculated using the questions available on the AoU database and participants were characterized as Adequate, Marginal, or Limited health literacy by their score.
For healthcare access variables, explicit AoU survey questions including “During the past 12 months, have you seen or talked to a general doctor who treats a variety of illnesses?”, “During the past 12 months, were you told by a health care provider or doctor’s office that they did not accept your health care coverage?”, “In regard to your health insurance or health care coverage, how does it compare to a year ago?”, “During the past 12 months, was there any time when you needed any of the following, but didn’t get it because you couldn’t afford it?”, and “Have you delayed getting care for any of the following reasons in the past 12 months?” were tabulated.
Finally, for treatment utilization, any Current Procedural Terminology (CPT)-documented physical therapy referral or lumbar fusion procedure was recorded within 2 years of initial DLDD diagnosis. Any All of Us-coded prescription for muscle relaxants, neuropathic agents, steroid injections, or opioids was similarly encoded.
Statistical Analysis
Participant characteristics, including age, sex at birth, education, employment status, insurance, and income level, and healthcare outcomes were described using counts and frequencies by race and ethnicity and compared across cohorts using chi square analyses. Multivariate logistic regressions, adjusted for age, sex at birth, education, employment status, insurance, and income level, were performed to identify independent associations between race and ethnicity and study outcomes. All analyses were completed using Python programming within the web-based platform Jupyter, as designated by the AoU research program. A P-value of <0.05 was considered statistically significant.
Results
Participant Demographics
Participant Characteristics
Health Literacy
Health Literacy Across Racial and Ethnic Groups
Healthcare Access
Barriers to Healthcare Across Racial and Ethnic Groups in the Past 12 Months
Forest Plot of Racial and Ethnic Disparities in Barriers to Healthcare in the Past 12 Months
Healthcare Utilization
Healthcare Utilization Across Racial and Ethnic Groups Within 2 Years of Initial Diagnosis of Degenerative Lumbar Disc Disease
Forest Plot of Racial and Ethnic Disparities in Healthcare Utilization Within 2 Years of Initial Diagnosis of Degenerative Lumbar Disc Disease
Discussion
The clinical and functional burden of DLDD varies considerably across demographic and socioeconomic subgroups. This study identified significant racial and ethnic disparities in health literacy, access to care, and healthcare utilization among patients with DLDD. In particular, Black, Hispanic, Other racial groups were shown to have worse health literacy, greater access-related barriers to care, and higher rates of nonoperative management than White patients. Despite a majority of participants being over age 65 and therefore eligible for Medicare, the persistence of access and affordability barriers among minority groups likely reflects underinsurance, variation in Medicare Advantage and supplemental plan coverage, and structural inequities in out-of-pocket costs. These factors help explain why denials and cost-related delays were still observed despite near-universal Medicare eligibility. These findings, derived from a large, nationally representative dataset, underscore the need for targeted interventions to promote equitable access and standardize DLDD management across populations.
Health literacy is a well-established predictor of health outcomes and patients with limited health literacy tend to have higher rates of hospitalization, increased incidence of chronic illness, lower utilization of preventive health services, and poorer self-reported health. 14 In this study, Black, Hispanic, Other racial groups consistently demonstrated lower health literacy, as measured by the BRIEF Health Literacy score, compared with White patients. Such disparities are closely linked to socioeconomic factors, including lower educational attainment, lower income, and language barriers, all of which disproportionately affect racial and ethnic minorities.14,15 These align with present study’s demographic findings, which revealed notable differences in education, insurance coverage, income across racial groups. Among all groups, Hispanic patients were most likely to have limited health literacy, followed by Black, and Other patients. Limited English proficiency may be a major driver of this trend, as many Hispanic patients prefer or require health information in Spanish, yet access to professional interpretation services remain inconsistent across healthcare settings.16-18 Additional factors such as acculturation level, immigration status, perceived discrimination, and mistrust of healthcare systems may further impede health literacy and access among Hispanic patients.16,19
This study also underscores persistent barriers to healthcare access, with Black, Hispanic, and Other patients reporting increased difficulty in affording care, including prescription medications and follow-up visits. These findings are consistent with previous population-based analyses showing that Black and Hispanic individuals have higher rates of foregone or delayed medical care due to cost, despite post-Affordable Care Act gains.20,21 Similarly, another study has demonstrated that these groups have substantially higher odds of being unable to afford medications and of delaying refills to save money. 22 Among low-income Medicare beneficiaries, loss of Medicaid supplemental insurance has been associated with greater difficulty accessing care, fewer outpatient visits, fewer medication fills in Black and Hispanic populations. 23 These disparities may be explained by lower rates of private or employer-based supplemental coverage in racial minority patients, which exacerbate the disproportionate impact of cost-sharing and higher burden of insurance gaps.20,24 Beyond affordability, the present study found that Black, Hispanic, and Other patients reported higher rates of delayed medical care due to lack of transportation, compared with White patients. This may be primarily due to greater reliance on public transportation among Black and Hispanic individuals, which can lead to markedly longer travel time for medical visits. 25 In addition, residential segregation often locates racial minority communities farther from high quality care and reliable transit networks, creating more delays in care. 25
With respect to healthcare utilization, this study revealed that Black patients were significantly more likely than White patients to receive nonoperative therapies, such as physical therapy, muscle relaxants, neuropathic agents, and opioids, within 2 years of their initial diagnosis of DLDD. Notably, opioid use was highest among Black patients compared with all other racial groups. Racial disparities in the delivery of health care have been documented across multiple surgical domains, with Black patients persistently being less likely to receive surgical interventions. 26 Differences in access and referral patterns further contribute to these gaps, as racial minority patients often have reduced access to specialty and rehabilitation services and receive fewer or later referral to surgical care, despite similar or greater disease severity.27,28 Such disparities in prescription and referrals may be influenced by implicit bias, as studies have shown that interracial clinical encounters are more likely to involve lower-quality communication, potentially affecting care planning and decision making. 29 Moreover, hospitals serving predominantly Black and Hispanic patients often have fewer financial resources, lower reimbursement rates, and low-quality infrastructure for advanced procedures.30,31 Emergency department utilization patterns in the present study further illustrate disparities in care continuity. Emergency department visits were least common among White patients, whereas Black and Hispanic patients reported significantly higher utilization. This likely reflects limited access to a usual source of primary care, resulting in greater reliance on the emergency department for management of ongoing chronic conditions. 32 These patterns are compounded by disproportionate Medicaid coverage or lack of insurance among racial minority patients, which restricts access to non-emergency outpatient care. 33 Structural factors within Medicaid, such as lower payment rates and narrower provider networks, may further reduce access to care outside the emergency department. 33
The present study has several potential limitations. First, its retrospective cross-sectional study design precludes assessment of long-term outcomes, such as DLDD progression or treatment efficacy across racial and ethnic groups, thereby limiting our understanding of downstream impact of these disparities. Second, several variables of the study, including health literacy, access barriers, education level, and income were self-reported and thus subject to recall or reporting bias. Third, unmeasured confounding factors such as social support, geographic proximity to care, and cultural factors may also have contributed to observed disparities. Finally, the AoU database does not include clinical measures of disease severity, which may have influenced healthcare utilization patterns and outcomes.
Conclusion
In conclusion, racial and ethnic minorities with DLDD were significantly more likely than White patients to experience limited health literacy, difficulty accessing care, and higher utilization of nonoperative treatments. These disparities likely reflect the complex interplay of demographic, socioeconomic, and structural determinants of health, which ultimately shape treatment pathways and outcomes. Reducing these gaps will require targeted efforts tailored to the needs of racial minority groups, including addressing language barriers, expanding resource availability, improving affordability, and enhancing insurance coverage to ensure equitable diagnosis, treatment, and outcomes in DLDD.
Footnotes
Ethical Considerations
Institutional Review Board approval was waived as the All of Us Research Program dataset is de-identified and publicly accessible to approved researchers.
Author Contributions
EY: Writing—original draft preparation; writing—review and editing.
SJ: Writing—original draft preparation; writing—review and editing.
MS: Conceptualization; methodology; project administration; critical revision of manuscript.
AY: Writing—original draft preparation; writing—review and editing.
AHM: Formal analysis; data interpretation.
AD: Supervision; critical revision of manuscript.
SC: Supervision; critical revision of manuscript.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.
Declaration of conflicting interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.