- A computer model projected that among overweight or obese patients with cirrhosis related to nonalcoholic steatohepatitis, bariatric surgery would outperform lifestyle intervention in terms of life expectancy and quality of life
- Bariatric surgery was cost effective for overweight patients as well as for those with mild to severe obesity
- Gastric bypass was associated with the largest increases in life expectancy and quality of life, but sleeve gastrectomy was the most cost effective
- The slightly superior weight loss attributable to gastric bypass is probably not worth the higher cost of the procedure
Obesity is the most common risk factor for nonalcoholic steatohepatitis (NASH); among patients with compensated cirrhosis, it nearly triples the risk of decompensation. For many of these patients, weight loss can improve or stabilize fibrosis and decrease portal hypertension.
Bariatric surgery often has durable effects on weight loss, but little is known about outcomes in patients with NASH cirrhosis. Jagpreet Chhatwal, PhD, senior scientist at the Institute for Technology Assessment and former researcher in the Division of Gastroenterology, Chin Hur, MD, MPH, gastroenterological researcher, and their colleagues recently used computer modeling to evaluate bariatric surgery for NASH cirrhosis. In JAMA Network Open, they report that surgery outperformed both usual care and intensive lifestyle intervention across all weight classes and that it was cost effective for both obese and overweight patients.
Evaluating Approaches to Care
The researchers used a Markov-based model to assess the cost-effectiveness of four strategies on patients who originally had NASH and compensated cirrhosis:
- Usual care (no weight loss intervention)
- Intensive lifestyle intervention
- Laparoscopic sleeve gastrectomy
- Laparoscopic Roux-en-Y gastric bypass
Transitions between health statuses (e.g., from compensated cirrhosis to decompensated cirrhosis, or from hepatocellular carcinoma to liver transplant) occur at fixed time intervals; in this study, each cycle was one year long. Data from existing medical literature was used to plug variables into the model.
The model was applied to patients in four weight classes: overweight (BMI 25.0–29.9), mild obesity (BMI 30.0–34.9), moderate obesity (BMI 35.0–39.9) and severe obesity (BMI ≥40.0). The outcomes were life-years (an expression of life expectancy gained as a result of the intervention), quality-adjusted-life-years (QALYs, a measure of how an intervention affects both survival and quality of life) and total costs.
Gain in Life-Years and QALYs
All weight loss strategies involved a gain in life-years and QALYs, compared with usual care. Specifically:
- Sleeve gastrectomy was associated with an increase in QALYs of between 0.263 (overweight) and 1.180 (severe obesity) and an increase in life-years of 0.693 to 1.930
- Gastric bypass was associated with an increase in QALYs of 0.263 to 1.207 and an increase in life-years of 0.694 to 1.947
- Intensive lifestyle intervention was associated with an increase in QALYs of 0.004 to 0.216 and an increase in life-years of 0.012 to 0.114
The results did differ according to BMI category:
- For patients with any degree of obesity, gastric bypass involved the greatest increase in life-years and QALYs, followed by sleeve gastrectomy and then intensive lifestyle intervention
- For overweight patients, gastric bypass involved only 0.001 additional life-year compared with sleeve gastrectomy and essentially an equal number of QALYs
The researchers expressed costs as 2017 U.S. dollars and evaluated them from the perspective of a third-party payer. Sleeve gastrectomy was the most cost-effective strategy for patients in all weight categories. For gastric bypass, all incremental cost-effectiveness ratios exceeded the commonly accepted willingness-to-pay threshold of $100,000 per QALY.
Bariatric surgery remained cost-effective for obese patients in sensitivity analyses, which included varying the probability of surgical mortality and complications. This was true even in patients with mild obesity and even when the researchers assumed that weight loss would have only a small benefit on the progression of liver disease.
The importance of these analyses is that it's often unclear to physicians and patients how the risks and benefits of bariatric surgery should be weighed in the setting of cirrhosis.
The Bottom Line
These findings suggest that the benefits of bariatric surgery may outweigh the risks in eligible individuals and that sleeve gastrectomy provides a more favorable combination of risks, benefits and costs compared with gastric bypass. Future research should investigate the impact of bariatric surgery on the progression of NASH cirrhosis in affected patients.
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