Insulin Resistance Is Central to Long-Term Reversal of Histologic Nonalcoholic Steatohepatitis After Metabolic Surgery

Abstract

Context: Nonalcoholic steatohepatitis (NASH) is considered the hepatic counterpart of metabolic syndrome.

Objective: This work aimed to investigate the determinants of NASH reversal in patients undergoing biliopancreatic diversion (BPD) in a 5-year follow-up study.

Methods: This prospective study was conducted at Policlinico Universitario Agostino Gemelli. A total of 37 patients underwent fine-needle liver biopsy during BPD. Ultrasonography-guided percutaneous liver biopsy was obtained 5 years after the operation. The primary outcome of our study was histologic NASH reversal at 5-year follow-up. To better characterize the clinical variables involved in the resolution of NASH, we also compared patients without histologic NASH resolution at 5 years with those in whom NASH had disappeared.

Results: At follow-up, NASH had reversed in 56.5% of the patients. The NAFLD activity score (NAS) improved from 3.7 ± 0.93 to 2 ± 1.11 (P < .001). Fibrosis reversed in 16% patients (P = .022), and 32% improved (95% CI, 0.05-0.54). No significant differences in body mass index or clinical parameters changes explained the effect of surgery on NASH, apart from the measure of insulin sensitivity post surgery. The Homeostasis Model Assessment of Insulin Resistance decreased from 3.31 ± 1.72 at baseline to 1.73 ± 1.08 (P < .001) after BPD, and the Matsuda index improved from 2.66 ± 1.79 to 4.73 ± 3.05 (P < .001). The lipid profile normalized (total cholesterol from 4.75 ± 1.18 to 3.32 ± 0.77 mmol/L, P < .001; low-density lipoprotein cholesterol from 2.92 ± 0.91 to 1.60 ± 0.51 mmol/L, P = .0001; high-density lipoprotein cholesterol from 0.97 ± 0.33 to 1.10 ± 0.35 mmol/L, P = .023; triglycerides from 2.52 ± 1.6 to 1.47 ± 0.67 mmol/L, P = .003). Neural network analysis showed that the end-study Matsuda index discriminated between responders and nonresponders with high accuracy (receiver operating characteristic area under the curve = 0.98%).

Conclusion: Remission of NASH is driven by reversal of whole-body insulin resistance post intervention.

Keywords: NAFLD; NASH; insulin resistance; liver biopsy; metabolic surgery; obesity.