Weight loss interventions in people with NAFLD appear to be associated with consistently improved biomarkers of liver disease in the short to medium term.
However a systematic review and meta-analysis found there was less evidence for long-term health outcomes.
The review identified 22 studies, comprising 2,588 participants, which investigated the impact of behavioural weight loss programs (BWLPs), pharmacotherapy or bariatric surgery on measures of liver disease.
The meta-analysis found more intensive weight loss interventions were associated with a weight loss of about 3.61 kg.
And there was “clear evidence” of improvements in biochemical markers of liver disease including alanine aminotransferase (ALT) and aspartate transaminase (AST) levels.
Liver stiffness, the NAFLD Activity Score (NAS) and the presence of definite NASH also decreased.
There were also associated improvements in liver steatosis measured by histologic examination, magnetic oukidisresonance imaging, or ultrasonography.
However there was no evidence of changes in histological scores for inflammation, ballooning or fibrosis.
“In a post hoc analysis, the changes in weight, ALT, and AST were larger in studies that included only participants who were overweight than in studies that included participants irrespective of weight status with strong evidence of subgroup differences,” the study said.
Half of the studies did not report on adverse events however gastrointestinal symptoms were the most commonly reported adverse events in the pharmacotherapy and surgical trials.
The researchers said the findings should lead to stronger recommendations for weight loss in patients with NAFLD.
“Clinicians may use these findings to counsel people with NAFLD on the expected clinically significant improvements in liver biomarkers after weight loss and direct the patients toward valuable interventions.”
“Because BWLPs have cardiometabolic advantages, which make them cost-effective, referral to these programs is likely to be particularly valuable for this population at high risk for cardiovascular disease.”
An Invited Commentary in JAMA Internal Medicine said the study “builds a compelling case for implementing formal weight loss programs as a mainstay in the treatment of NAFLD.”
The authors said the efficacy of lifestyle interventions focused on weight loss for NAFLD was especially important given the limited pharmacotherapy options available.
They said only vitamin E in non-diabetic patients and pioglitazone had been shown to be of benefit on liver histology.
“Importantly, both metformin and statins—key therapies for the metabolic syndrome (commonly seen in NAFLD patients)—are safe to use in NAFLD. However, there are no conclusive data supporting their use for the sole purpose of treatment of NAFLD.”
“Many drugs targeting a variety of mechanisms are currently in development, though cost and risk of long-term adverse effects may limit the adoption of pharmacotherapy.”