Inpatient Medicare Total Hip Arthroplasties have Distinct Characteristics and are Less Likely to Achieve Substantial Clinical Benefit for Hip Disability and Osteoarthritis Outcome Score for Joint Replacement: Implications for Centers for Medicare and Medicaid Services Patient-Reported Outcome Measures Policy.

Background: The Centers for Medicare & Medicaid Services (CMS) has mandated the collection of patient-reported outcome measures (PROMs) after total hip arthroplasty (THA). However, this policy's performance and its representativeness of the entire Medicare THA population remain unclear. This study aimed to 1) report PROMs completion rates for Medicare THA patients, and 2) compare the inpatient and outpatient Medicare THA patients in terms of demographics and achievement of substantial clinical benefit (SCB).

Methods: A prospective cohort of Medicare patients ≥ 65 years undergoing primary THA (n = 7,950) between 2016 to 2022 from a single healthcare system was analyzed. The PROMs completion rates, demographics, 1-year Hip Disability and Osteoarthritis Outcome Scores-Joint replacement (HOOS JR), and SCB-JR were compared.

Results: Completion rates for PROMs were similar (∼80%) for inpatient and outpatient THAs across all CMS-mandated variables. However, 1-year HOOS-JR completion rates were lower at 51% for inpatients and 63% for outpatients. Inpatient Medicare patients represented 38.5% of the THA cohort. These were older (median age 72 versus 71 years, P < 0.001), had higher BMI (29.0 versus 28.3, P<0.001), lower education levels (14 versus 15 years, P < 0.001), with higher comorbidities (CCI one versus zero, P < 0.001), compared to outpatients. Inpatients had worse baseline HOOS JR scores (39.9 versus 46.7, P < 0.001) and were less likely to achieve SCB (80.1 versus 84.1%, P < 0.001). On adjusted analysis, outpatient status was associated with 29% lower odds of failure to achieve SCB (OR [odds ratio] 0.71, 95% CI [confidence interval] 0.60 to 0.84, P < 0.001).

Conclusion: At our institution, CMS-mandated variable capture rates exceeded the minimum requirements. As CMS begins public reporting, the differing demographics, higher comorbidity burden, and worse PROMs among inpatient versus outpatient Medicare THA patients must be acknowledged. Collecting PROMs from both groups is crucial for representativeness, but the cost and logistical challenges require further research to ensure feasibility and sustainability.