The NAFLD fibrosis score : a prognostic predictor for mortality and liver complications among NAFLD patients

Background: The prognostic indicators for long-term outcomes of non alcoholic fatty liver disease (NAFLD) patients have not been well studied. We aimed to validate the NAFLD Fibrosis Score in the Thai NAFLD population and to assess whether the severity of liver fibrosis estimated by the NAFLD Fibrosis Score can predict the mortality of patients with NAFLD in long-term follow up. Methods: We divided our study into 2 phases; the first phase is a cross sectional study to collect 115 Thai NAFLD patients prospectively during 2007-2010 in King Chulalongkorn Memorial Hospital (KCMH) to validate the NAFLD Fibrosis Score. The second phase is a historical cohort design by using the existing data of NAFLD patients diagnosed during 1980 and 2000 drawn from the Rochester Epidemiology Project to analyze. Of 479 patients with NAFLD, 302 patients were included. We used the NAFLD Fibrosis Score for separating NAFLD patients with and without advanced liver fibrosis. Results: According to the first phase study, 115 Thai NAFLD patients with mean age of 50.5 ± 12.4 years were included. Seventy seven of the Thai NAFLD patients (67%) were in a group of low risk of advance fibrosis by using NAFLD Fibrosis Score. Advanced fibrosis was shown in 15 (13%) patients. Using the ROC curve, the NAFLD Fibrosis Score at baseline of >-1.5 was used for predicting significant liver fibrosis with a sensitivity of 53%, specificity of 70%, PPV of 21% and NPV of 91%. For phase 2 study, a total of 302 NAFLD patients (mean age 47.3 ± 12.9 years) were followed-up for an average of 11.9 ± 3.9 years. A low probability of advanced fibrosis (score <-1.5 at baseline) was found in 60% while intermediate or high probability of advanced fibrosis (score ≥-1.5) was found in 40%. At the end of follow up, 55 patients (18%) developed primary endpoints including 39 patients (13%) who died during follow-up. In a multivariate analysis a higher NAFLD Fibrosis Score at baseline and presence of new onset of CHD were significantly predictive of death (OR = 2.6 and 9.2, respectively; p <0.0001). Conclusions: The NAFLD Fibrosis Score has a high NPV in Thai NAFLD patients. A higher NAFLD Fibrosis Score at baseline and presence of new onset of CHD were significantly predictive of death.