Introduction

Lumbar disc herniations (LDH) are amongst the most common spinal pathologies, resulting in substantial individual, societal, and economic burden.  Despite increased appreciation for the importance of social determinants of health, the role that these factors play in patients with lumbar disc herniations is poorly defined.  We set out to elucidate the influence of these social factors on the manifestation of LDH in various populations by investigating the association between insurance status and patient reported outcome measures (PROMs) in the setting of lumbar disc herniations.

Methods

Baseline patient-reported outcome measures (PROMS) were reviewed from 924 patients with lumbar disc herniation according to the International Classification of Diseases, tenth edition (ICD-10) code from 2015-2020 within our institutional system. The Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function Short Form 10a (PF10a), PROMIS Global-Mental, PROMIS Global-Physical, and visual analogue scale (VAS) for back and leg pain were assessed. Descriptive analysis was conducted with Kruskall-Wallis or chi-squared testing, and negative binomial regression modeling used with insurance type as the primary predictor and all other demographic factors including age, gender, race, language, ethnicity, comorbidity index, and median geospatial household income as covariates.

Results

Of 924 included patients, the mean age was 58.4 +/- 15.2 years, with 52.6% male patients. The Medicaid population had a greater proportion of Black, Hispanic, and non-English speaking patients compared with commercially insured patients. The Charlson Comorbidity index was significantly higher in the Medicare group. Baseline scores were poorer for Medicaid patients across all PROMs compared with commercially insured patients, exceeding minimal clinically important differences (MCID) in several domains including PF10 (37.2 versus 33.2 points), global physical score (39.9 versus 34.1 points), and VAS low back pain (5.5 versus 6.9 points) but not leg pain (5.3 versus 5.8 points). These differences remained significant on adjusted analysis.

Discussion

This work is the first to our knowledge to leverage PROMs in a large dataset to demonstrate the systematic disparities in the manifestation of lumbar disc herniation symptoms in different populations.  Our findings are consistent with a growing body of literature pointing to the fact that underserved populations report more significant disability and pain metrics as compared to other groups when experiencing the same musculoskeletal pathologies.  Notably, increases in baseline axial back pain, but not leg pain, in Medicaid patients compared with other insurance types may herald poor treatment response to surgical management. As health care stakeholders increasingly leverage PROMs for treatment algorithms and as measures of care value, it is imperative that we gain a deeper understanding of the extrinsic factors that affect these metrics, so as not to create health care governance or policies that might adversely affect certain populations.  Further, future work will need to investigate the etiology of these differences in baseline PROMs for musculoskeletal pathologies and determine if these are patient driven, or if they may be a result of health system asymmetries in delayed or suboptimal access to care.