Evaluating Costs, 90-Day Readmissions and Post-Discharge Care for Primary Total Knee (TKR) and Total Hip Replacements (THR) Using an Episode of Care Bundled Payment Perspective

Shweta Pathak, The University of Texas School of Public Health


Background: The literature evaluating 90-day episodes is recent and mostly limited to the Medicare population. The present study expands upon existing knowledge on 90-day episode costs and readmissions in a younger and privately insured population. Understanding the cost and post-discharge service component differences is crucial for successful implementation of bundled payments in total joint replacement (TJR). Methods: We obtained claims data for the years 2008 to 2013 from Blue Cross Blue Shield of Texas (BCBSTX) for primary TJR procedures. We used an episode of care approach to evaluate cost determinants of a 90-day episode-of-care using multilevel regression. Costs were aggregated using “allowed amount” payments to providers. Then, we evaluated whether specific post-discharge care follow-up events such as initiation of rehabilitative care and visits to a primary care physician or orthopedic specialist were significantly associated with the likelihood of any 90-day readmission using logistic GEE models. Results: The mean total cost for a 90-day episode for TJR was $47,700. A prolonged length of stay (RR:1.19; 95% CI, 1.15-1.23; p< 0.001), any 90-day inpatient readmission (RR: 1.64; 95% CI, 1.57-1.71; p< 0.001), use of computer-assisted surgery (RR:1.031; 95% CI, 1.004-1.059; p< 0.05), having a home health discharge (RR:1.029; 95% CI, 1.013-1.046; p< 0.001) and very high morbidity burden (RR:1.105; 95% CI, 1.062-1.150; p< 0.001) were all significant determinants of TJR costs. Provider-level cost predictors included location in an urban area (RR: 1.29; 95% CI, 1.17-1.42; p< 0.001), high case mix (RR: 0.94; 95% CI, 0.89-0.95; p< 0.001) and large provider size (RR: 1.082; 95% CI, 1.009-1.161; p< 0.05). When examining post-discharge services, majority of patients (89%) with a direct home discharge (with or without home health component) began rehabilitative care during the first week after discharge. For 90-day readmissions, there was a significant interaction effect between type of TJR (hip or knee) and rehabilitative care initiated more than two weeks after discharge (0.50 OR, 95% CI 0.31-0.83, p=0.007). In comparison to those who started rehabilitation care within the first week of discharge, there were significantly higher odds of a 90-day ED visit in those who started more than two weeks after discharge (OR 1.37, 95% CI 1.07-1.76). Conclusions: Inpatient care contributed a large proportion of total costs for 90-day care episodes for primary TJR. There was significantly high variation in patient and provider level costs. We found that, in general, patients who started rehabilitation more than two weeks after discharge had a significantly higher probability of a 90-day readmission and a 90-day ED visit than those who started rehabilitation within the first week of discharge. Our results underscore the importance of rehabilitation timing when developing post-discharge care protocols for patients with a direct home discharge. There is scope for future studies that explore whether similar cost and post-discharge care service trends exist among other payers.^

Subject Area

Public health|Health care management

Recommended Citation

Pathak, Shweta, "Evaluating Costs, 90-Day Readmissions and Post-Discharge Care for Primary Total Knee (TKR) and Total Hip Replacements (THR) Using an Episode of Care Bundled Payment Perspective" (2017). Texas Medical Center Dissertations (via ProQuest). AAI10270481.