High BMI, Must Deny? Not Necessarily

No matter the level of a patient’s obesity, total hip arthroplasty (THA) is a cost-effective intervention, says new work from Canada.

The study, “Cost-Effectiveness of Total Hip Arthroplasty versus Nonoperative Management in Normal, Overweight, Obese, Severely-Obese, Morbidly-Obese, and Super-Obese Patients: A Markov Model,” appears in the August 24, 2018 edition of The Journal of Arthroplasty.

Edward M. Vasarhelyi, M.D., M.Sc., assistant professor in the Division of Orthopaedic Surgery at Western University, London Health Sciences Centre – University Hospital, in London, Ontario, Canada, and study co-author explained his surprising conclusion to OTW. “Many developed countries are facing increasing budgetary pressures across the spectrum of healthcare. We have seen changes in funding models, such as bundled care payments. These models have put pressure on clinicians and administrators which, in some healthcare systems, has resulted in the refusal of surgery for patients above arbitrary BMI [body mass index] cut offs.”

“We do know that there are increased complications, and associated costs, as a patient’s BMI increases, but what was unclear is whether it is still cost effective to offer total hip arthroplasty rather than non-operative management for symptomatic end-stage arthritis of the hip. By better understanding the cost effectiveness of surgical treatment of patients stratified based on their BMI, we can guide clinical decision making, health policy and health funding formulas.”

The authors wrote, “We constructed a state-transition Markov model to compare the cost-utility of THA and NM [nonoperative management] in the six BMI groups over a 15-year period. Model parameters for transition probability (risk of revision, re-revision, and death), utility and costs (inflation adjusted to 2017 U.S. dollars) were estimated from the literature.”

Dr. Vasarhelyi said, “This study quantified the marginal improvements in quality-adjusted life-years over the incremental cost-effectiveness ratio for total hip arthroplasty versus non-operative management of symptomatic end-stage hip osteoarthritis in patients of varying BMI levels. We found that for all BMI groups in virtually all probabilistic scenarios, the ICER [incremental cost effectiveness ratio] for THA is less than $50,000/QALY [quality-adjusted life-year].”

“This is a conservative threshold in the U.S., and based on this analysis, we can show that establishing a BMI cut-off for THA eligibility results in the unnecessary loss of healthcare access for patients at the higher BMI levels.”

“It is important to optimize modifiable risk factors prior to surgery; however, it is debatable as to whether a patient’s BMI is modifiable in a meaningful way. As such, we have shown that even in the super-obese patients, at conservative willingness-to-pay thresholds, it is cost-effective to perform a total hip arthroplasty in symptomatic patients. Based on this, patients should not be denied access to surgery based on their BMI. In addition, we hope that this work can serve as a basis to encourage remuneration that is appropriately stratified for surgeons and treating facilities who are caring for the higher risk patients, because although the procedure is cost effective, total hip arthroplasty in the higher BMI patients is associated with additional costs.”

“Total hip arthroplasty is a cost-effective procedure to improve the quality of life of patients with symptomatic hip osteoarthritis of all BMI levels. It is important have a thorough discussion of the risks and benefits of surgery, and to optimize the health of morbidly and super-obese patients, but they should not be denied an arthroplasty on the basis of their BMI.”