The Effect of Payer Type on Patient-Reported Outcomes in Total Joint Arthroplasty Is Modulated by Baseline Patient Characteristics

Patient-reported outcomes (PROs) are gaining an important role in the assessment of quality of care. There are currently limited data on the effect of payer type on PROs in total joint arthroplasty (TJA). This study compared both disease-specific and general health PROs among patients stratified according to their payer type.

Our institutional joint registry was queried for patients who underwent primary, elective, and unilateral hip and knee arthroplasty. Patients were divided according to their insurance type at the time of surgery into 3 groups: Medicaid, Medicare, or commercial. The outcomes assessed were the net changes in PROs as well as absolute scores at 6 months and 1 year. Six of the most commonly used PROs were assessed: Short Form-12 physical and mental components, Western Ontario and McMaster Universities Osteoarthritis Index, Single Assessment Numerical Evaluation, University of Californian Los Angeles activity level rating, and Oxford Hip Score. Analysis of variance and covariance were used.

We evaluated 756 procedures (273 Medicaid, 270 Medicare, and 213 commercial insurance). Medicaid patients had significantly lower mean baseline scores across all PROs compared to either Medicare or commercial insurance patients. Medicaid patients were also more likely to be smokers, live alone, have lower educational level, African-American, and have nonprimary osteoarthritis as the indication for TJA. At 1-year follow-up, the net mean outcome gains were comparable among the 3 payer types ( P > .05), but Medicaid patients continued to score lower while Medicare and commercial insurance patients continued to score higher ( P < .01). When adjusting for all baseline differences among Medicaid patients, the negative effects of payer type resolved except for Oxford Hip Score which remained lower in the Medicaid group ( P = .006).

When using PROs to assess the value of care, the preoperative to postoperative changes are a better indicator of surgical success than comparing absolute values, especially in Medicaid patients. While TJA imparts similar net improvements to patients of all payer types, Medicaid coverage is a predictor of lower absolute outcome scores at any given time as result of increased baseline health burden (eg, depression, tobacco smoking, and poor overall well-being). Arthroplasty surgeons should be aware of these factors when counseling patients and seek optimization when necessary. The findings should be taken into account by stakeholders when constructing value-based payment models. Further research is needed to better understand the barriers leading to higher prevalence of increased health disparities among Medicaid beneficiaries and how to effectively address them.