Surgical Weight Loss Interventions
Their cost effectiveness for patients with knee OA & class III obesity
By Aleksandra Kostic, BSE, Valia Leifer, BA, & Elena Losina, PhD, MSC
Why was this study done? Weight loss can alleviate knee osteoarthritis (OA) related pain for patients with knee OA and obesity. However, current knee OA treatment guidelines do not address weight loss strategies other than diet and exercise. Bariatric surgery can yield substantial, sustainable weight loss among individuals with class III obesity (BMI ≥40 kg/m2), but its value for patients with knee OA is uncertain due to concerns about cost, efficacy and adverse events.
What were the study methods? We used the Osteoarthritis Policy Model (OAPol) to evaluate the effects of Roux-en-Y gastric bypass (RYGB) and laparoscopic sleeve gastrectomy (LSG) bariatric surgery on lifetime costs and quality of life in patients with class III obesity and moderate knee OA. Each bariatric surgery strategy was considered in conjunction with usual knee OA care, which consisted of non-steroidal anti-inflammatory drugs, physical therapy, intra-articular corticosteroid injections, tramadol, oxycodone, total knee replacement and revision total knee replacement. We calculated incremental cost-effectiveness ratios (ICERs), discounted at 3% per year, which represent the difference in lifetime costs to the difference in quality adjusted life years (QALYs) between the two treatment strategies. We performed sensitivity analyses to evaluate the effect of uncertainty in model inputs on results.
What were the key findings? Compared with usual care only, both RYGB and LSG reduced opioid utilization and increased total knee replacement (TKR) utilization. LSG yielded less benefit at a higher cost than RYGB (most likely due to lower and less sustainable weight loss). RYGB yielded a very favorable ICER ($5,300/QALY).
What were the main conclusions? Bariatric surgery provides substantial weight loss and other clinical benefits. Our results suggest RYGB offers a better value than LSG for a population with class III obesity and knee OA.
What are the implications for patients? Patients with class III obesity and knee OA may consider bariatric surgery to alleviate knee OA-related symptoms. They should discuss the risks and benefits of different weight loss strategies with their providers.
What are the implications for clinicians? Patients with class III obesity and moderate knee OA may benefit from bariatric surgery, which may reduce future opioid use. It is reasonable to discuss bariatric surgery as a weight loss strategy with this patient population.
