Variation in Diagnoses for Hip Arthroplasty Among New York State Hospitals: Implications for the Comprehensive Care for Joint Replacement Model.

BACKGROUND: The Comprehensive Care for Joint Replacement model is designed to minimize costs and improve quality for Medicare patients undergoing joint arthroplasty. The cost of hip arthroplasty (HA) episode varies depending on the preoperative diagnosis and is greater for fracture than for osteoarthritis. Hospitals that perform a higher percentage of HA for OA may therefore have an advantage in the Comprehensive Care for Joint Replacement model. The purposes of this study are to (1) determine the variability in underlying diagnosis for HA in New York State hospitals, and (2) determine hospital characteristics, such as volume, associated with this.

METHODS: The New York Statewide Planning and Research Cooperative System database was used to identify 127,206 primary HA procedures from 2010 to 2014. The data included underlying diagnoses, age, length of stay, and total charges. Hospitals were categorized by volume and descriptive statistics were used.

RESULTS: OA was the underlying diagnosis for HA for 74.2% of all patients; this was significantly higher for high-volume (89.30%) and medium-volume (74.9%) hospitals than for low-volume hospitals (58.4%, P < .05). HA for fracture was significantly more common at low-volume hospitals (32.4%) compared to medium-volume (18.0%) and high-volume (4.7%) hospitals (P < .05). Length of stay was significantly greater at low-volume hospitals for all diagnoses.

CONCLUSION: High-volume hospitals perform a higher ratio of HA cases for OA compared to fracture, which may lead to advantages in patient outcomes and cost. The variation in underlying diagnosis between hospitals has financial implications and underscores the need for HAs to be risk stratified by preoperative diagnosis.