A simple clinical risk score based on age, sex and BMI predicts long-term survival in NAFLD: analysis from a large public dataset

Background Non-alcoholic fatty liver disease (NAFLD) represents a growing global health challenge, yet no widely accepted clinical tool exists to stratify patients by mortality risk using basic demographic and anthropometric parameters. Aim To develop and validate a simple clinical score based on age, sex and BMI to predict long-term survival in NAFLD patients. Methods We conducted a retrospective survival analysis on 17,549 patients with NAFLD, using data derived from the Nonalcoholic Fatty Liver Disease Adult Database 2 (NAFLD Adult Database 2), managed by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). A three-point clinical risk score was developed by assigning one point each for age >60 years, male sex, and BMI >30 kg/m² (range 0–3). The primary outcome was overall survival, defined by the variable status over follow-up time (futime). Kaplan-Meier survival estimates and Cox proportional hazards models were used to assess the prognostic utility of the score. Results Among included patients, 46.7% were male and 7.8% experienced the primary outcome. The distribution of risk scores was: 0 (1.4%), 1 (25.5%), 2 (50.4%), and 3 (22.8%). Median survival increased from 2111 months in the score 0 group to 2327 months in the score 2 group. Patients with score 3 had a modest but statistically significant increase in risk compared to score 0 (HR = 1.09; 95% CI: 1.00–1.17; p = 0.044), while score 2 was associated with lower risk (HR = 0.87; 95% CI: 0.79–0.97; p = 0.010). Kaplan-Meier curves showed clear separation of survival probabilities across score categories. The 5-year survival was 100% (score 0), 99.7% (score 1–2), and 99.4% (score 3). Conclusion A clinical score based on age, sex and BMI provides a simple yet effective tool for mortality risk stratification in NAFLD. This model may help guide follow-up strategies and early interventions in clinical settings.