HOPPS: evolution of a CMS process

Is the New Outpatient Prospective Payment System Classification for Outpatient Total Knee Arthroplasty Appropriate?

BACKGROUND

In 2018, the Centers for Medicare and Medicaid Services removed total knee arthroplasty (TKA) from the inpatient-only list, resulting in payment through the Outpatient Prospective Payment System with an average $3157 reduction. The purpose of this study is to determine if the reimbursement is justified by comparing the difference in facility costs between inpatient and outpatient TKAs.

METHODS

We identified 4496 consecutive primary TKA procedures performed at 2 hospitals from 2015 to 2019. Itemized facility costs were calculated using a time-driven activity-based costing algorithm. Outpatient procedures were defined as those with a length of stay of less than 2 midnights (3851, 86%). Patient demographics, comorbidities, and itemized costs were compared between groups. A multivariate regression analysis was performed to determine the independent effect of outpatient status on true facility costs.

RESULTS

Outpatient TKA patients had lower mean postoperative personnel costs ($1809 vs $947, P < .001), supply costs ($4347 vs $4229, P < .001), and overall total facility costs ($7371 vs $6937, P < .001) than inpatient TKA patients. Controlling for a younger patient cohort with fewer medical comorbidities, outpatient status was associated with a reduction in total facility costs of $972 (95% confidence interval $883-$1060, P < .001) compared to inpatient TKA.

CONCLUSION

Outpatient TKA costs hospitals nearly $1000 per patient less than inpatient TKA, yet the average difference in Medicare reimbursement for an outpatient procedure is $3157 less per patient. Centers for Medicare and Medicaid Services should reconsider the Outpatient Prospective Payment System classification of TKA to better incentivize surgeons to perform TKA as a lower cost outpatient procedure when safe and appropriate.

Emergent Challenges in Determining Costs for Economic Evaluations

This paper describes methods of determining costs for economic evaluations of healthcare and considers how cost determination is being affected by recent developments in healthcare. The literature was reviewed to identify the strengths and weaknesses of the four principal methods of cost determination: micro-costing, activity-based costing, charge-based costing, and gross costing. A scoping review was conducted to identify key trends in healthcare delivery and to identify costing issues associated with these changes. Existing guidelines provide information on how to implement various costing methods. Bottom-up costing is needed when accuracy is paramount, but top-down approaches are often the only feasible approach. We describe six healthcare trends that have important implications for costing methodology: (1) reform in payment mechanisms; (2) care delivery in less restrictive settings; (3) the growth of telehealth interventions; (4) the proliferation of new technology; (5) patient privacy concerns; and (6) growing efforts to implement guidelines. Some costs are difficult to measure and have been overlooked. These include physician services for inpatients, facility costs for outpatient services, the cost of developing treatment innovations, patient and caregiver costs, and the indirect costs of organizational interventions. Standardized methods are needed to determine social welfare and productivity costs. In the future, cost determination will be facilitated by technological advances but hindered by the shift to capitated payment, to the provision of care in less restrictive settings, and by heightened concern for medical record privacy.