Losing weight through lifestyle changes can significantly improve several measures of nonalcoholic fatty liver disease, particularly if patients lose at least 10% of their body weight, and bariatric surgery is a valid alternative if diet and exercise fail, according to two studies reported in the August issue of Gastroenterology (2015 Apr. 9 [ doi:10.1053/j.gastro.2015.04.005 ]).

Global rates of nonalcoholic fatty liver disease (NAFLD) are up because of the “parallel epidemics” of obesity and type 2 diabetes mellitus, said Dr. Eduardo Vilar-Gomez of the National Institute of Hepatology in Havana, Cuba, who authored the study of lifestyle changes. There are no approved therapies for the more aggressive form of NAFLD, steatohepatitis, he and his associates said. In past studies, patients who lost about 7%-10% of their body weight substantially improved their NAFLD activity score and had reductions in steatosis, lobular inflammation, and ballooning, but the results did not extend to fibrosis, and prospective studies of the effect of lifestyle changes on histology are lacking, the researchers added .

To fill the gap, they followed 293 adults with histologically confirmed nonalcoholic steatohepatitis who completed a 52-week lifestyle intervention program that included keeping a food diary, restricting saturated fats to less than 10% of total intake, and walking at least 200 minutes a week. Patients had not received hypolipidemic treatment in the preceding 3 months and were not allowed to take insulin sensitizers or vitamin E, both of which are potentially beneficial for nonalcoholic steatohepatitis, the investigators said.

At the end of the yearlong program, steatohepatitis had resolved in 25% of patients, 47% had lower NAFLD activity scores, and 19% had regression of fibrosis, the researchers reported. Although only 30% of participants lost at least 5% of their body weight, weight loss correlated positively with resolution of steatohepatitis and with 2-point reductions in histologic activity scores (P <.001). Among patients who lost at least 10% of their body weight, 90% had resolution of steatohepatitis, 45% had regression of fibrosis, and all had improved histologic activity scores, even if they had negative risk factors such as female sex, a baseline body mass index of at least 35 kg/m2, and a baseline fasting glucose level of at least 5.5 mmol/L, the investigators added. “Our findings support the current recommendation for weight loss using lifestyle modification as the first step in the management of patients with nonalcoholic steatohepatitis,” they wrote.

But what if lifestyle changes fail? The impact of bariatric surgery on nonalcoholic steatohepatitis has not been well studied, said Dr. Guillaume Lassailly at CHRU Lille (France). He and his associates therefore followed 109 morbidly obese patients (BMI ≥40 kg/m2) with biopsy-confirmed nonalcoholic steatohepatitis who underwent bariatric surgery at a single tertiary hospital (Gastroenterology 2015 Apr. 25 [ doi:10.1053/j.gastro.2015.04.014 ]) .

One year after surgery, 85% of patients had achieved disease resolution (95% confidence interval, 75.8%-92.2%), the investigators reported. Stratifying patients by baseline Brunt scores showed that those with milder presurgical disease were more likely to have complete resolution than were patients whose disease was severe (94% vs. 70%; P <.05), the researchers added. Histologic analyses supported the findings, revealing steatosis in 60% of presurgical tissue samples, compared with 10% of samples taken a year after surgery. In addition, average NAFLD disease scores dropped from 5 to 1 (P <.001), hepatocyte ballooning decreased in 84% of samples, lobular inflammation decreased in 67%, and Metavir fibrosis scores dropped in one-third of specimens.

Notably, BMI scores for patients with persistent postsurgical disease dropped by an average of only 9.1, compared with 12.3 for patients whose disease resolved (P = .005), said the researchers. Gastric bypass surgery achieved greater weight loss and improvements in disease status, compared with laparoscopic banding, they added. “The encouraging results of the present study suggest that bariatric surgery should be tested in multicenter, randomized controlled trials in morbidly or severely obese patients with nonalcoholic steatohepatitis who did not respond to lifestyle therapy,” they wrote.

The Cuban National Institute of Gastroenterology and Ministry of Health partially funded the study by Dr. Vilar-Gomez and his associates. The French Ministry of Health and the Conseil Regional Nord-Pas de Calais supported the work by Dr. Lassailly and his colleagues. All investigators declared having no relevant financial conflicts of interest.