HOMA-IR: An independent predictor of advanced liver fibrosis in nondiabetic non-alcoholic fatty liver disease

Background and Aim Although non-alcoholic fatty liver disease (NAFLD) is common in the general population, identifying patients with advanced fibrosis remains a challenge. We investigated whether the homeostasis model assessment parameter of insulin resistance (HOMA-IR), an index of IR and one of the most important metabolic factors, is an independent predictive factor for advanced fibrosis in nondiabetic patients with NAFLD. Methods This was a retrospective, cross-sectional multicenter study. We included 361 patients with biopsy-proven NAFLD who had not been diagnosed with type 2 diabetes mellitus: 175 (48%) were women and 48 (13%) had advanced fibrosis. We used simple random sampling; the sampling ratio of the estimation and validation groups was 7:3. A logistic model was constructed for both the estimation and validation groups. The explanatory variables were age >= 49 years, sex (women), body mass index >= 26.7 kg/m(2), the presence of hypertension, presence of dyslipidemia, fasting plasma glucose level >= 98 mg/dL, fasting immune reactive insulin level >= 12.0 mu U/mL, and HOMA-IR >= 2.90. The median HOMA-IR of the patients was 2.88 (interquartile range: 2.1-4.8). Results In the estimation group, univariate and multivariate analyses showed that age, dyslipidemia, and HOMA-IR were independent predictors of advanced fibrosis. In the validation group, only age and HOMA-IR were found to be independent predictors of advanced fibrosis. Conclusions Homeostasis model assessment parameter of insulin resistance was an independent predictor of advanced liver fibrosis in nondiabetic patients with NAFLD. Given that most patients with NAFLD are nondiabetic, it is important to set goals with respect to improving IR to subsequently reduce liver fibrosis.