Use of Metabolic Scores and Lipid Ratios to Predict Metabolic Dysfunction-Associated Steatotic Liver Disease Onset in Patients with Inflammatory Bowel Diseases

<b>Background/Objectives:</b> Metabolic dysfunction-associated steatotic liver disease (MASLD) is increasingly recognized in inflammatory bowel disease (IBD) patients due to chronic inflammation and metabolic disturbances. However, reliable non-invasive biomarkers for MASLD prediction in this population are lacking. This study evaluated the predictive value of metabolic scores and lipid ratios for MASLD onset in IBD patients. <b>Methods:</b> An observational retrospective study was conducted on 358 IBD patients at the "Renato Dulbecco" Teaching Hospital in Catanzaro, Italy, in a period between 1 January 2021 and 31 December 2024. Clinical and laboratory data, including metabolic scores and lipid ratios, were analyzed using the chi-square and Kruskal-Wallis tests as appropriate. Post hoc comparisons were conducted using Dunn's test. Receiver operating characteristic analysis assessed their predictive accuracy for MASLD. <i>p</i> < 0.05 was considered significant. <b>Results:</b> IBD-MASLD patients had a significantly higher body mass index (BMI, 27 ± 4 vs. 22 ± 2 kg/m²; <i>p</i> < 0.001), waist circumference (100 ± 11 vs. 85 ± 4 cm; <i>p</i> < 0.001), other anthropometric parameters, metabolic scores, and lipid ratios than IBD-only patients. The metabolic score for insulin resistance [METS-IR, area under curve (AUC = 0.754)] and waist circumference (AUC = 0.754) exhibited the highest predictive accuracy, followed by the lipid accumulation product (LAP, AUC = 0.737), BMI (AUC = 0.709), and triglyceride/high-density lipoprotein (TG/HDL, AUC = 0.701). Insulin resistance scores, including the homeostasis model assessment of insulin resistance (AUC = 0.680) and triglyceride-glucose index (AUC = 0.674), were of moderate predictive use. The visceral adiposity index (AUC = 0.664) and low-density lipoprotein/high-density lipoprotein (AUC = 0.656) showed lower discriminative ability, while the fibrosis-4 index (AUC = 0.562) had the weakest diagnostic performance. <b>Conclusions:</b> Our findings suggest that MASLD in IBD is primarily driven by cardiometabolic dysfunction. The introduction of the METS-IR, LAP, and TG/HDL into clinical assessments of IBD patients could prove useful in preventing liver and cardiovascular complications in this setting.