Comparison of noninvasive scoring systems for the prediction of nonalcoholic fatty liver disease in metabolic syndrome patients

Over half of metabolic syndrome (MetS) patients have nonalcoholic fatty liver disease (NAFLD). To prevent its complications, standard routine screening is required, but the human-resource and budgetary implications need to be taken into consideration. This study compared the performances of 4 noninvasive scoring systems in predicting NAFLD in MetS patients. They were the fatty liver index, hepatic steatosis index, lipid accumulation product index, and nonalcoholic fatty liver disease in metabolic syndrome patients scoring system (NAFLD-MS). Scores were determined for 499 MetS patients, including 249 patients in a type 2 diabetes mellitus (T2DM) subgroup. Ultrasonography was used to diagnose NAFLD. The accuracies and performance of the scoring systems were analyzed using published cutoff values, and comparisons were made of their areas under receiver operating characteristic curves, sensitivities, specificities, positive and negative predictive values, and likelihood ratios. NAFLD was detected in 68% of the MetS patients and 77% of the MetS patients with T2DM. According to the areas under receiver operating characteristic curves, fatty liver index and hepatic steatosis index provided better performances in predicting NAFLD. NAFLD-MS provided the highest specificity of 99% among the MetS patients as a whole, and it provided even better accuracy with similar performance when applied to the subgroup of MetS patients with T2DM. The maximum cost avoidance from unnecessary ultrasonography was also reported by using NAFLD-MS. In terms of simplicity and ease of calculation, the lipid accumulation product index and NAFLD-MS are preferred. All 4 scoring systems proved to be acceptable for predicting NAFLD among MetS and T2DM patients in settings where the availability of ultrasonography is limited. NAFLD-MS provided the highest specificity and cost avoidance, and it is simple to use. All 4 systems can help clinicians decide further investigations.