Table 1.
NAFLD index and their hallmarks.
| NAFLD Index | Predictors | Hallmarks | Interpretation |
|---|---|---|---|
| Fatty liver index (FLI) | Fatty Liver Index (FLI) = ey / (1 + ey) × 100. Where y = 0.953 × ln(triglycerides, mg/dL) + 0.139 × BMI, kg/m2 + 0.718 × ln (GGT, U/L) + 0.053 × WC, cm − 15.745) [95] |
Identified NAFLD and the optimal cut-off point with accuracy. |
FLI < 30, no FL (with a negative likelihood ratio of up to 0.2); 60 < FLI < 30, Inconclusive FLI ≥ 60, FL present (with a likelihood ratio starting from 4.3) |
| Lipid accumulation product (LAP) | LAP for men = (WC [cm]–65) × (TG concentration [mmol/L]) LAP for women = (WC [cm] − 58) × (TG concentration [mmol/L]) [96] |
Associated with the presence and severity of NAFLD, among young and aged population [97,98]. NOT able to predict liver fat content [99]. | The optimal cut-off value for LAP was 31.6 with sensitivity of 88% (95% CI, 77–96%), specificity of 82% (95% CI, 76–87%) for males and with a sensitivity of 66% (95% CI, 52–78%), specificity of 93% (95% CI, 88–96%) for females. |
| Hepatic steatosis index (HSI) | Hepatic steatosis index (HSI) = 8 × (ALT/AST ratio) + BMI (+2, if female; +2, if diabetes mellitus) [89]. | A simple, efficient screening tool for NAFLD, used for selecting individuals for liver ultrasonography [89]. | At values of < 30.0 or > 36.0, HSI ruled out NAFLD with a sensitivity of 93.1%, or detected NAFLD with a specificity of 92.4%, respectively [89]. |
| The ZJU (Zhejiang University) index | ZJU index = BMI (Kg/m2) + FPG (mmol/L) + TG (mmol/L) + 3 × ALT (IU/L)/AST (IU/L) ratio (+2, if female) [90]. | Confirmed to have significance in terms of diagnosing NAFLD [90]. | At a value of <32.0, the ZJU index could rule out NAFLD with a sensitivity of 92.2%, and at a value of >38.0, the ZJU index could detect NAFLD with a specificity of 93.4% [90]. |
| NAFLD fibrosis score | NAFLD Score = −1.675 + (0.037 × age [years]) + (0.094 × BMI [kg/m2]) + (1.13 × IFG/diabetes [yes = 1, no = 0]) + (0.99 × AST/ALT ratio) − (0.013 × platelet count [×109/L]) − (0.66 × albumin [g/dL]) [92] | Identifies patients without severe fibrosis, comparatively more difficult to estimate [91]. | Low cut-off score (−1.455): advanced fibrosis ruled out with high accuracy (negative predictive value of 93% and 88% in the estimation and validation groups, respectively). High cut-off score (0.676), advanced fibrosis diagnosed with high accuracy (positive predictive value of 90% and 82% in the estimation and validation groups, respectively) [92]. |
| BARD score | Based on AST/ALT ratio, presence of diabetes and BMI [100]. | Identifies patients without severe fibrosis, but easier to estimate and does not have indeterminate results [91]. | BMI ≥28 = 1 point, AAR of ≥0.8 = 2 points, DM = 1 point A score of 2–4 was associated with an OR for advanced fibrosis of 17 (confidence interval 9.2 to 31.9) and a negative predictive value of 96% [100]. |
| FIB-4 index | FIB-4 Score = age ([yr] × AST [U/L])/((PLT [109/L]) × (ALT [U/L])1/2) [101]. | In patients <35 or >65 years old, the score has been shown to be less reliable [94,101]. | At a cut-off of <1.45 in the validation set, the negative predictive value to exclude advanced fibrosis (stage 4–6) was 90% with a sensitivity of 70%. A cut-off of >3.25 had a positive predictive value of 65% and a specificity of 97%. Using these cut-offs, 87% of the 198 patients with FIB-4 values outside 1.45–3.25 would be correctly classified [101]. |
Abbreviations: AAR, AST/ALT ratio; BMI, body mass index; DM, diabetes mellitus; FPG, fasting plasma glucose; TG, triglycerides; ALT, alanine transaminase; AST, aspartate transaminase; GGT, gamma-glutamyl transpeptidase; OR, odd ratio; WC, waist circumference.