Triglyceride–glucose–C-reactive protein index for identifying metabolic dysfunction-associated fatty liver disease in nonobese adults

Metabolic dysfunction-associated fatty liver disease (MAFLD) is highly prevalent in nonobese individuals. Its pathological mechanism is closely related to insulin resistance and chronic low-grade inflammation, but there is a lack of effective early identification tools in clinical practice. To investigate the association of the triglyceride–glucose–C-reactive protein (TyG-CRP) index with MAFLD in nonobese adults. This cross-sectional study enrolled 694 nonobese adults (body mass index < 25 kg/m²). Participants were categorized into non-MAFLD ( n = 480) and MAFLD ( n = 214) groups based on standardized diagnostic criteria. Multivariable logistic regression was used to evaluate the association between the TyG-CRP index and MAFLD. The diagnostic performance was assessed using receiver operating characteristic (ROC) curves, and logistic regression analyzed the correlation between the TyG-CRP index and MAFLD severity. TyG-CRP index was significantly higher in the MAFLD group than in the non-MAFLD group (8.65 ± 0.83 vs. 7.89 ± 0.82, P < 0.001). After adjustment for age and sex, each 1-unit increase in the TyG-CRP index was associated with higher odds of MAFLD (OR = 2.94, 95% CI: 2.32–3.71, P < 0.001). The area under the receiver operating characteristic curve for TyG-CRP index (0.745) was slightly higher than that of the triglyceride–glucose (TyG) index (0.729), although this difference was not statistically significant ( P = 0.229). Subgroup analysis confirmed the consistent association of the TyG-CRP index with MAFLD across different age and sex groups ( P > 0.05). Among MAFLD patients, the TyG-CRP index was positively associated with steatosis severity. Specifically, compared with mild steatosis (S1), each 1-unit increase in the TyG-CRP index was associated with a 98% increase in the odds of severe steatosis (S3 vs. S1: OR = 1.98, 95% CI: 1.33–2.95, P < 0.001). The TyG-CRP index is strongly associated with MAFLD and its severity in nonobese adults, showing good discriminative ability, although not statistically superior to the simpler TyG index. It may serve as a simple, complementary clinical tool for early identification and risk stratification. However, these findings are derived from a single-center Chinese health check-up population and may not generalize to other ethnicities or clinical settings. This study assessed the triglyceride–glucose–C-reactive protein (TyG-CRP) index, a novel composite biomarker integrating insulin resistance and systemic inflammation, for identifying metabolic dysfunction-associated fatty liver disease (MAFLD) in nonobese adults. The TyG-CRP index demonstrated a numerically higher AUC compared to the traditional triglyceride–glucose index, although the difference was not statistically significant, and was independently associated with MAFLD risk and severity. This cost-effective tool leverages routine biochemical parameters, offering potential as a complementary marker for early identification and risk stratification of MAFLD in nonobese individuals.