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Abstract
Background: Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide and is closely linked to obesity and insulin resistance. Liver biopsy and advanced imaging remain limited by cost, invasiveness, and availability, particularly in resource-limited settings. The triglyceride-glucose (TyG) index, derived from routine fasting glucose and triglyceride measurements, has been proposed as an inexpensive surrogate marker of insulin resistance and hepatic steatosis. This study aimed to evaluate the diagnostic performance of the TyG index for detecting ultrasonography-confirmed NAFLD among overweight adults at a resource-limited tertiary care hospital in Pakistan.
Materials and Methods: This cross-sectional study was conducted in the adult medical outpatient and inpatient population at Federal Government Polyclinic Hospital, Islamabad, enrolling 200 consecutive overweight adults (body mass index ≥ 23.0 kg/m² per the World Health Organization Asian classification). Demographic, anthropometric, and biochemical variables were recorded, and the TyG index was calculated as ln[fasting triglycerides (mg/dL) × fasting plasma glucose (mg/dL)/2]. Abdominal ultrasonography, performed by a radiologist blinded to biochemical results, served as the reference standard for NAFLD. Diagnostic performance was assessed using sensitivity, specificity, predictive values, and receiver operating characteristic (ROC) curve analysis. All data were entered and analyzed using SPSS version 23.0. The statistical significance was set at p ≤ 0.05.
Results: NAFLD was diagnosed by ultrasonography in 88 of 200 participants (44.0%). Participants with NAFLD had significantly higher body mass index, waist circumference, fasting glucose, serum triglycerides, and liver enzymes than those without NAFLD (p<0.001 for all). The mean TyG index was significantly higher in the NAFLD group than in the non-NAFLD group (9.03 ± 0.43 vs 8.49 ± 0.43; p<0.001). At the optimal cutoff of 8.70, the TyG index yielded a sensitivity of 79.5%, specificity of 70.5%, positive predictive value of 68.0%, negative predictive value of 81.5%, and an overall diagnostic accuracy of 74.5%, with an area under the ROC curve of 0.81 (95% CI 0.75–0.87).
Conclusion: The TyG index demonstrates good diagnostic performance for identifying NAFLD among overweight individuals and represents a practical, inexpensive, and readily available screening tool, particularly valuable in resource-limited healthcare settings where advanced imaging modalities are not routinely accessible.