Cost‐Effectiveness of Surgical Weight‐Loss Interventions for Patients With Knee Osteoarthritis and Class III Obesity

Abstract

Objective. Class III obesity (body mass index [BMI] ≥40 kg/m 2 ) is associated with worse knee pain and total knee replacement (TKR) outcomes. Because bariatric surgery yields sustainable weight loss for individuals with BMI ≥40 kg/m 2 , our objective was to establish the value of Roux-en-Y gastric bypass (RYGB) and laparoscopic sleeve gastrectomy (LSG) in conjunction with usual care for knee osteoarthritis (OA) patients with BMI ≥40 kg/m 2 .Methods. We used the Osteoarthritis Policy model to assess long-term clinical benefits, costs, and costeffectiveness of RYGB and LSG. We derived model inputs for efficacy, costs, and complications associated with these treatments from published data. Primary outcomes included quality-adjusted life-years (QALYs), lifetime costs, and incremental cost-effectiveness ratios (ICERs), all discounted at 3%/year. This analysis was conducted from a health care sector perspective. We performed sensitivity analyses to evaluate uncertainty in input parameters.Results. The usual care + RYGB strategy increased the quality-adjusted life expectancy by 1.35 years and lifetime costs by $7,209, compared to usual care alone (ICER = $5,300/QALY). The usual care + LSG strategy yielded less benefit than usual care + RYGB and was dominated. Relative to usual care alone, both usual care + RYGB and usual care + LSG reduced opioid use from 13% to 4%, and increased TKR usage from 30% to 50% and 41%, respectively. For cohorts with BMI between 38 and 41 kg/m 2 , usual care + LSG dominated usual care + RYGB. In the probabilistic sensitivity analysis, at a willingness-to-pay threshold of $50,000/QALY, usual care + RYGB and usual care + LSG were cost-effective in 70% and 30% of iterations, respectively.Conclusion. RYGB offers good value among knee OA patients with BMI ≥40 kg/m 2 , while LSG may provide good value among those with BMI between 35 and 41 kg/m 2 .

Cost‐Effectiveness of Weight‐Loss Interventions Prior to Total Knee Replacement for Patients With Class III Obesity

“…Weight-loss regimens are associated with a risk of complications that reduce QoL and incur costs. Additional details on modeling weight-loss interventions in OAPol have been published (18).…”

“…For calculation of costs, in the year of surgery, we included the cost of surgery ($20,291) (34), surgeon fees ($1,222) (35), anesthesiologist fees ($1,081) (36), and 6 follow‐up visits ($158/visit) (37). In the years following surgery, we included an annual cost of 1 physician visit ($158) and dietary supplements ($98) (18).…”

“…For the 2 strategies not including bariatric surgery (immediate TKR and lifestyle weight-loss strategies), we derived complication rates and implant failure rates stratified by BMI as kg/m 2 (<30, 30 to <40, ≥40), with a higher BMI leading to a greater probability of complications and implant failure (Table 2) (26,27). We accounted for a differential risk of revision and prescription opioid overdose following surgery based on a prior history of opioid use (1,18). We also stratified the cost of primary and revision TKR by BMI using costs data reported by Chen et al (primary TKR cost: $19,711 for BMI ≥40 kg/m 2 ; $19,327 for BMI 30 to <40 kg/m 2 ; and $19,038 for BMI <30 kg/m 2 ) (1).…”

Knee Osteoarthritis in Patients With High BMI: The Role of an Orthopaedic Surgeon

“…In addition, it can reduce the risk of complications after TKR [49]. From a cost-effectiveness point of view, bariatric surgery offers good value for money for those patients [50].…”