Table 1. . Original studies used in generating fatty liver disease indices.
| Index (year) | Variables/index formula | Patient characteristics | Primary results | Comments | Ref. |
|---|---|---|---|---|---|
| FLI (2006) | BMI, waist circumference, triglycerides and GGT FLI = (e0.953×loge(triglycerides)+0.139×BMI+0.718×loge(GGT)+0.053×waistcircumference−15.745)/ (1 + e0.953×loge(triglycerides)+0.139×BMI+0.718×loge(GGT)+0.053×waistcircumference−15.745) × 100 |
224 residents with suspected liver disease (mean age = 58) and 287 without (mean age = 57) from Campogalliano | FLI had an accuracy of 0.84 Score <30 rules out NAFLD with a negative likelihood ratio of 0.2 and score >60 rules in NAFLD with a positive likelihood ratio of 4.3 |
Derived from ultrasound, did not use gold-standard liver biopsy Cannot classify severity of NAFLD Decreased accuracy when applied to obese patients |
[13,18] |
| HSI (2010) | BMI, ALT/AST ratio, sex and diabetes mellitus status HSI = 8 × (ALT/AST ratio) + BMI (+2 if diabetes mellitus; +2 if female) |
5362 patients with NAFLD and 5362 matched controls with a mean age of 52.2 from Seoul National University Hospital | AUROC in validation group was 0.819 Score <30 rules out NAFLD with sensitivity of 93.9% and score >36 rules in NAFLD with specificity of 93.1% |
Derived from ultrasound, did not use gold-standard liver biopsy Significant correlation with degree of fatty liver Detected fatty liver diseases in pediatrics group with high accuracy |
[12] |
| FLDI (2013) | BMI, triglycerides, ALT/AST ratio and hyperglycemia FLD index = BMI + triglycerides + 3 × (ALT/AST ratio) + 2 × HG (presence of hyperglycemia = 1, absence of hyperglycemia = 0) |
3463 patients with NAFLD and 3463 matched controls with a mean age of 43.9 from Rizhao People's Hospital | AUROC was 0.817 in validation set Score <28 excludes NAFLD with sensitivity of 94.9% while >37 detects NAFLD with specificity of 96% |
Derived from ultrasound, did not use gold standard liver biopsy Cannot classify the severity of NAFLD Not validated in non-Chinese populations |
[19] |
| ZJU Index (2015) | BMI, triglycerides, ALT/AST ratio and fasting glucose level ZJU index = BMI + fasting blood glucose + triglycerides + 3× ALT/AST (+2 if female) |
4801 NAFLD patients and 4801 matched controls with a mean age of 47.97 from the First Affiliated Hospital Zhejiang University | AUROC was 0.826 in validation cohort Score <32 rules out NAFLD with sensitivity of 92.4% and score >38 rules in NAFLD with specificity of 93.3% |
Derived from ultrasound but was validated in a small sample of patients with liver biopsy High predictive values for younger patients (<40) |
[20] |
| FSI (2016) | Age, sex, BMI, triglycerides, hypertension, diabetes and ALT/AST ratio FSI = −7.981 + 0.011 × age (years) − 0.146 × sex (female = 1, male = 0) + 0.173 × BMI (kg/m2) + 0.007 × triglycerides (mg/dl) + 0.593 × hypertension (yes = 1, no = 0) + 0.789 × diabetes (yes = 1, no = 0) + 1.1 × ALT/AST ratio ≥1.33 (yes = 1, no = 0) |
1181 participants with a mean age of 50 from Framingham Heart Study third-generation cohort and 4489 adults from National Health Nutrition Examination Survey III | C-statistic = 0.760 in validation cohort At a score of 23, sensitivity is 79% and specificity is 71% |
Derived from CT, did not use gold-standard liver biopsy Index was validated in multiethnic cohort Initial derivation does not account for those with viral hepatitis |
[21] |
ALT: Alanine aminotransferase; AST: Aspartate aminotransferase; AUROC: Area under receiver operating curve; CT: Computed tomography; FLDI: Fatty Liver Disease Index; FLI: Fatty Liver Index; FSI: Framingham Steatosis Index; GGT: Gamma-glutamyl transferase; HG: Hyperglycemia; HSI: Hepatic Steatosis Index; NAFLD: Nonalcoholic fatty liver disease; ZJU: Zhejiang University Index.