Decomposing the drivers of polypharmacy disparities in United States adults with and without physical disabilities.

Abstract

Background: Polypharmacy, the concurrent use of multiple medications, is a growing public health concern, particularly among adults with physical disabilities. Individuals with physical disabilities often experience a higher burden of chronic conditions and greater healthcare needs, increasing risk of polypharmacy.

Objectives: To examine differences in polypharmacy between adults with/without physical disabilities and identify the extent to which observable clinical, sociodemographic, and lifestyle factors explain these differences.

Method: This is a cross-sectional study using the 2022 Medical Expenditure Panel Survey (MEPS), a nationally representative dataset of the U.S. non-institutionalized population. Adults aged ≥18 years (N = 11,242) were included. Polypharmacy was defined as the concurrent use of medications from ≥6 therapeutic drug classes during a MEPS interview round (approximately 180-days). Physical disability was defined using self-reported limitations in physical functioning. We applied Rao-Scott Chi-square tests, survey-weighted multivariable logistic regression, and nonlinear Blinder-Oaxaca decomposition to assess disparities and quantify contributing factors.

Results: Polypharmacy was more prevalent among adults with physical disabilities (51.9%) compared to those without (9.0%, p < 0.001). In fully adjusted models, physical disability remained significantly associated with polypharmacy (AOR = 1.31, 95% CI: 1.01-1.70, p = 0.038). Decomposition analysis revealed that 80.9% of the disparity was explained by measured characteristics, with health status and socioeconomic factors contributing the largest proportions, whereas 19.1% remained unexplained.

Conclusions: Adults with physical disabilities experience substantially higher rates of polypharmacy, largely explained by differences in health status and socioeconomic characteristics. These findings highlight potential targets for interventions to optimize medication use and reduce disparities.