The cost-effectiveness of outpatient surgery for primary total hip arthroplasty in the United States: a computer-based cost-utility study.

PURPOSE

The purpose of this study was to perform a cost-effectiveness analysis of outpatient versus inpatient total hip arthroplasty (THA) in the USA, considering complication probability and the potential cost of such complications.

METHODS

A cost-effectiveness analysis was conducted from the societal perspective to evaluate the incremental cost and effectiveness of inpatient THA compared to outpatient THA over a lifetime horizon. Effectiveness was expressed in quality-adjusted life years (QALYs). Costs, expressed in 2019 US dollars, transition probabilities, and health utilities were derived from the literature. The primary outcome was the incremental cost-effectiveness ratio (ICER), with a willingness to pay (WTP) threshold set at $50,000/QALY. 1-way and probabilistic sensitivity analyses was performed to evaluate the effect of the various variables on the model.

RESULTS

In the base case, inpatient THA was more effective in terms of total utility (10.36 vs. 10.30 QALY), but also more costly ($48,155 ± 1673 vs. $43,288 ± 1, 606 for Medicare) than outpatient THA. Even with a lifetime horizon, the ICER was $81,116 per QALY and $140,917 per QALY for Medicare and private payer insurance, respectively, which is higher than the willingness to pay threshold. 1-way sensitivity analyses indicated that the variables having the most influence on the model were the utility of inpatient and outpatient THA and cost of inpatient and outpatient THA.

CONCLUSIONS

This model determined that for a WTP threshold set at $50,000/QALY, outpatient THA is more cost-effective than inpatient THA from a societal perspective. Despite this, surgeons must weigh clinical factors first and foremost in determining if an individual patient can be safely operated on in the outpatient setting.