Morbidly obese patients experience greater utility with bariatric surgery prior to THA

LAS VEGAS — Despite a 2-year delay in performing total hip arthroplasty for weight loss and metabolic optimization, morbidly obese patients who underwent bariatric surgery prior to total hip arthroplasty experienced greater utility compared with total hip arthroplasty alone, according to results presented at the American Academy of Orthopaedic Surgeons Annual Meeting.

Researchers constructed a state-transition Markov model to compare the cost-utility for patients with morbid obesity and end-stage hip osteoarthritis who underwent either immediate total hip arthroplasty (THA) or bariatric surgery 2 years prior to THA. Using data from the National Inpatient Sample and from the literature, the researchers assigned direct costs to each state and adjusted costs to 2013 U.S. dollars. When probabilities, utilities and costs were not available in the literature or the National Inpatient Sample, the researchers estimated these using expert opinion. Incremental cost-effectiveness ratio was the principal outcome measure of the study.

Emily Dodwell

Results showed fewer quality-adjusted life years (QALYs) were gained among morbidly obese patients who underwent THA alone vs. patients who underwent both bariatric surgery and THA. Although bariatric surgery generated $18,835 in additional costs, the researchers found the increased spending was offset by the QALYs gained. This resulted in an incremental cost-effectiveness ratio of approximately $10,552 per QALY between the two treatment strategies, well below the standard $100,000 per QALY willingness-to-pay, according to the researchers.

One-way sensitivity analysis showed stable results across broad ranges for independent model variables, whereas Monte Carlo simulation with 100,000 samples demonstrated bariatric surgery was cost-effective 82.1% of the time prior to THA.

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“Obesity is linked to less-favorable outcomes after joint replacement surgery, such as longer hospital stays, higher overall costs and higher failure rates,” researcher, Emily Dodwell, MD, an orthopedic surgeon at the Hospital for Special Surgery and assistant professor of orthopedic surgery at Weill Cornell Medical College, told Healio.com/Orthopedics. “We used a mathematical model (decision analysis) to simulate the outcomes and costs of each treatment path (hip replacement in obese patients vs. hip replacement after bariatric surgery and subsequent weight loss), based on results and costs that have been published in the literature. We found that surgical weight loss prior to joint replacement is a cost-effective option from a public payer standpoint in order to improve outcomes in obese patients who are candidates for joint replacement.” – by Casey Tingle

Reference:

Southren DL, et al. Poster #P078. Presented at: American Academy of Orthopaedic Surgeons Annual Meeting. March 24-28, 2015; Las Vegas.

Disclosures: Dodwell reports no relevant financial disclosures. Please see study abstract for a complete list of all other authors’ relevant financial disclosures.