SAN FRANCISCO – Bariatric surgery is an effective treatment for nonalcoholic steatohepatitis (NASH) in obese patients, a Markov model suggests.
Patients with all classes of obesity, including, mild, moderate, and severe, with all stages of fibrosis, experienced gains in life years following laparoscopic Roux-en-Y gastric bypass, compared with standard management and intensive lifestyle changes, based on the model, Dr. Kathleen Corey reported at the annual meeting of the American Association for the Study of Liver Diseases.
Surgery also increased quality-adjusted life years (QALY) in those with moderate and severe obesity with all fibrosis stages, those with mild obesity and F2-F3 fibrosis, and in overweight patients with F3 fibrosis, said Dr Corey of Massachusetts General Hospital, Boston.
The number of F3 patients needed to treat to prevent one liver-related death was favorable across all body mass indexes for those with stage F3 fibrosis. The number needed to treat to prevent one case of cirrhosis in these patients was six to seven, and to prevent one liver-related death was eight to 11, she said.
A cost-effectiveness analysis, with a willingness-to-pay threshold of less than $100,000, also showed that surgery was cost effective for all fibrosis stages for those with severe and moderate obesity.
“The [incremental cost-effectiveness ratio] for BMI of 35-39.9 [kg/m2] was $34,000, for those with a BMI of 40 or greater it was $26,000, and we found that with overweight patients with F3 fibrosis, the ratio was also favorable at $59,000,” she said.
More than 78 million American adults suffer from obesity, and the prevalence of obesity is rising nationwide, she said, adding that obesity results in annual medical costs exceeding $147 billion. Treatment options for obesity are limited, and weight regain after weight loss is frequent, Dr. Corey noted.
“However, bariatric surgery has been shown to be a very effective treatment for obesity. Surgery has been shown to significantly reduce mortality in patients, and reduces progression of many comorbidities, including diabetes,” she said.
Guidelines suggest that bariatric surgery is appropriate for patients with a body mass index of 40 or greater and for those with a BMI of 35 or greater if obesity-related comorbidities such as diabetes or obstructive sleep apnea are present, and data suggest that surgery is also of benefit in those with BMI below 35 with diabetes.
The question remains, though, whether nonalcoholic fatty liver disease (NAFLD) – the most common cause of liver disease in the United States – is an indication in itself for bariatric surgery.
NAFLD is strongly associated with obesity, and its progressive form – NASH – can lead to cirrhosis, hepatocellular carcinoma, and the need for liver transplantation.
“However, there are no FDA-approved therapies for NASH and no randomized controlled trials have been conducted to evaluate the role of bariatric surgery in NASH ... and appropriate BMI cutoffs in those with NASH have not been established,” Dr. Corey said.
Several nonrandomized prospective trials have, however, evaluated bariatric surgery in NASH patients with BMIs of 35 or greater with comorbidities, and in patients with BMIs of 40 or greater, and these have shown that NASH resolution can occur in up to 85% of patients at 1-5 years with fibrosis reduction seen in nearly a third, she said, adding that the risk-benefit ratio for surgery is unknown, as is the value of surgery in NASH patients with BMIs less than 35.
The current study looked at three treatment strategies, including standard management with lifestyle counseling; intensive lifestyle intervention based on a diabetes prevention program with lifestyle, nutrition, and exercise counseling; and bariatric Roux-en-Y gastric bypass in a hypothetical simulated cohort of 45-year-olds with NASH, F0-F3 fibrosis, and varying BMI values.
The findings, though limited by a lack of data on the impact of surgery on patients with a BMI of less than 35, and by evaluation of only one type of surgery, showed that bariatric surgery increased incremental life years at all weight and fibrosis stages vs. standard management and intensive lifestyle intervention, and that surgery increased QALY in those with moderate and severe obesity with all fibrosis stages, those with mild obesity and F2-F3 fibrosis, and in overweight patients with F3 fibrosis.
“We found that surgery was cost effective for F3 fibrosis in those with moderate and severe obesity and those with overweight. Randomized trials, though, are needed to assess the management of weight loss surgery for NASH before this can be recommended, certainly in patients with a BMI of less than 35,” she concluded.
Dr. Corey reported serving on an advisory committee or review panel for Gilead, and serving in a speaking or teaching role for Synageva.