Development and validation of a simple index system to predict nonalcoholic fatty liver disease

BACKGROUND/AIMS: Abdominal ultrasonography is useful for the detection and diagnosis of nonalcoholic fatty liver disease (NAFLD). The aims of this study were to establish a predictive model for the selection of subjects for abdominal ultrasonography for the diagnosis of NAFLD and to assess validity of the model. METHODS: The subjects included 901 people who visited the health examination center of the Busan Medical Center. We conducted multiple logistic regression analyses of potential risk factors to identify independent risk factors for NAFLD, and developed an index system. RESULTS: Four independent risk factors were identified. The index system was developed by assigning 1 clinical scoring point to approximately 0.7 logistic regression coefficients to each factor as follows: alanine aminotransferase/aspartate aminotransferase ratio >1.5 (odds ratio [OR], 2.22; 95% confidence interval [CI], 1.21-4.07; P=0.010), 1 point; γ-glutamyl transpeptidase >50 (OR, 2.15; 95% CI, 1.13-4.07; P=0.019), 1 point; triglyceride >150 mg/dL (OR, 1.92; 95% CI, 1.14-3.24; P=0.015), 1 point; 23 kg/m(2)≤BMI<25 kg/m(2) (OR, 3.68; 95% CI, 2.05-6.63; P<0.001), 2 points; and BMI 25 kg/m(2) (OR, 7.65; 95% CI, 4.29-13.62; P<0.001), 3 points. The area under the receiver operating characteristics curve was 0.797 (95% CI, 0.751-0.842), and when 3 points was used as a cut-off value, the sensitivity and specificity were 71.7% and 75.9%, respectively. CONCLUSIONS: NAFLD can be predicted through the clinical application of the index system established herein. If abdominal ultrasonography is used for high-risk patients, NAFLD will be diagnosed and managed in its early stage.