Effects of orlistat on APRI and FIB-4 scores in patients with obesity: a retrospective observational study

Metabolic dysfunction–associated steatotic liver disease (MASLD) is closely associated with obesity and diabetes mellitus (DM). Early identification of patients at risk of liver fibrosis is important for clinical management; however, liver biopsy is not routinely feasible, and fibrosis is therefore assessed using non-invasive surrogate indices. Orlistat is a widely used therapy for obesity, but its effects on non-invasive liver fibrosis scores remain unclear. This study aimed to evaluate changes in calculated fibrosis scores after orlistat treatment in patients with obesity. Data were retrospectively collected from 335 patients diagnosed with obesity who initiated orlistat treatment. Laboratory parameters and body weight measurements were obtained at the baseline, and at the 3rd, 6th, and 12th months following orlistat treatment. Weight changes were also recorded. MASLD not confirmed by biopsy was evaluated using calculated fibrosis scores. The Fibrosis-4 (FIB-4) index and Aspartate Transaminase-Platelet Ratio Index (APRI) are used to assess fibrosis, and the data were also obtained at the same endpoints. Of the 335 patients at baseline, data were available for 310, 134, and 39 patients at 3, 6, and 12 months, respectively. A significant reduction in weight and body mass index (BMI) was observed following orlistat treatment (p < 0.01). Repeated-measures analysis showed no significant change in FIB-4 scores (p = 0.46), whereas APRI scores decreased significantly (p < 0.01). When patients were stratified by a 5% weight-loss threshold, no differential effect on changes in FIB-4 or APRI scores was observed. In multiple linear regression analysis, changes in fibrosis scores were independent of sex, baseline weight, weight change during follow-up, presence of diabetes mellitus, and use of metformin or sodium–glucose cotransporter-2 inhibitors. Orlistat treatment resulted in significant weight loss and reductions in ALT and AST levels. While the APRI score decreased significantly with treatment, the FIB-4 score did not change significantly. The change in APRI score was independent of weight loss.