Validation of simple indexes for nonalcoholic fatty liver disease in western China: a retrospective cross-sectional study

Fatty liver index as an independent predictor of all-cause and disease-specific mortality

PURPOSE

This study aims to assess the prognostic value of the fatty liver index (FLI), a noninvasive tool for hepatic steatosis assessment, in predicting all-cause and disease-specific mortality.

METHODS

We linked data from the National Health and Nutrition Examination Survey III (1988-1994) with Public-Use Mortality Files, forming a cohort of 11 297 participants with a median follow-up period of 26.25 years. Cox proportional hazards models were used to evaluate the association between FLI and all-cause mortality, while Fine and Gray's models assessed the relationship between FLI and disease-specific mortality.

RESULTS

The FLI ≥ 60 was independently associated with an increased risk of all-cause mortality (hazard ratio = 1.24, P  < 0.001), as well as mortality from malignant neoplasms (hazard ratio = 1.18, P  = 0.048), diabetes (hazard ratio = 2.62, P  = 0.001), and cardiovascular diseases (CVDs) (hazard ratio = 1.18, P  = 0.018), compared to FLI < 30. No significant associations were found with Alzheimer's disease, influenza and pneumonia, chronic lower respiratory diseases, or renal disorders. Subgroup analyses indicated that individuals who were females aged 40-60 (hazard ratio = 1.67, P  = 0.003), non-overweight (hazard ratio = 1.75, P  = 0.007), or without abdominal obesity (hazard ratio = 1.75, P  = 0.007) exhibited a stronger association between FLI ≥ 60 and all-cause mortality.

CONCLUSION

These findings support the prognostic value of the FLI for predicting mortality from all causes, malignant neoplasms, diabetes, and CVDs. Targeted attention is needed in postmenopausal women, non-overweight, and non-abdominally obese populations.

Multi-dimensional comparison of abdominal obesity indices and insulin resistance indicators for assessing NAFLD

BACKGROUND

The prevalence of non-alcoholic fatty liver disease (NAFLD) keeps increasing annually worldwide. Non-invasive assessment tools for evaluating the risk and severity of the disease are still limited. Insulin resistance (IR) and abdominal obesity (ABO) are closely related to NAFLD.

METHODS

A retrospective large-scale, population-based study was conducted based on the data from the 2017-2018 cycle of the National Health and Nutrition Examination Survey (NHANES). Three ABO indices, namely lipid accumulation product (LAP), visceral obesity index (VAI), waist circumference-triglyceride index (WTI), and three IR indices, including triglyceride glucose index (TyG), homeostasis model assessment of insulin resistance (HOMA-IR) and metabolic score for insulin resistance (METS-IR), were analyzed and compared for their relationships with NAFLD based on weighted multivariable logistic regression, spearman correlation heatmap, smooth curve fittings. The area under the curve (AUC) of receiver-operating characteristic (ROC) curve was used to evaluate the diagnostic capability of these indices for NAFLD. Differences among the AUCs were calculated and compared by Delong test.

RESULTS

In total, 3095 participants were included in our study among which 1368 adults were diagnosed with NAFLD. All six indices presented positive associations with NAFLD. There was a claw-shaped curve between HOMA-IR, VAI, LAP and NAFLD while a smooth semi-bell curve was observed in TyG, METS-IR and WTI. LAP and HOMA-IR had the best diagnostic capability for NAFLD (LAP: AUC = 0.8, Youden index = 0.48; HOMA-IR: AUC = 0.798, Youden index = 0.472) while VAI (AUC = 0.728, Youden index = 0.361) showed the lowest predictive value. The correlation heat map indicated positive correlations between all six indices and liver function, hepatic steatosis and fibrosis severity. In the NAFLD group, IR indicators presented a stronger association with alanine aminotransferase (ALT) compared with ABO indices.

CONCLUSIONS

All six indices can screen NAFLD withLAP and HOMA-IR being possibly optimal predictors. IR indices may be more sensitive to identify acute hepatic injury in NAFLD patients than ABO indices.

The effect of dietary approaches to stop hypertension (DASH) diet on fatty liver and cardiovascular risk factors in subjects with metabolic syndrome: a randomized controlled trial

BACKGROUND

Metabolic syndrome (MetS) as a multifactorial disorder is associated with non-communicable diseases. The dietary approaches to stop hypertension (DASH) diet is a healthy dietary pattern. We investigated the effect of the DASH diet on fatty liver and cardiovascular risk factors in subjects with MetS.

METHODS

60 Subjects with MetS were assigned into the intervention group (DASH diet) or the control group (a healthy diet). Fatty liver index (FLI), hepatic steatosis index (HSI), waist circumference (WC), weight, body mass index (BMI), triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-c) and high-density lipoprotein cholesterol (HDL-c) were evaluated at the beginning and after intervention. Equations of fatty liver indices such as FLI and HSI are based on liver enzymes, anthropometric variables, sex and having diabetes.

RESULTS

30 subjects in the intervention group and 29 subjects in the control group completed the study. We found a significant reduction in the intervention group compared to the control group in FLI (-13.06 ± 10.03 vs. -2.90 ± 6.82;P < 0.001), HSI (-2.72 ± 2.59 vs. -0.81 ± 3.80;P = 0.02), WC (-6.02 ± 4.24 vs. -2.24 ± 4.28;P = 0.001), weight (-3.39 ± 2.53 vs. -1.51 ± 2.72;P = 0.008), BMI (-1.25 ± 0.93 vs. -0.56 ± 1.01;P = 0.008), DBP (-5.16 ± 3.92 vs. -1.50 ± 7.04;P = 0.01), SBP (-6.97 ± 8.21 vs. -1.36 ± 6.83;P = 0.006), TG (-18.50 ± 14.32 vs. 0.60 ± 23.81;P < 0.001), TC (-16.10 ± 17.94 vs. -5.07 ± 23.62;P = 0.04) and LDL-c (-13.50 ± 9.58 vs. -4.90 ± 18.28;P = 0.02). These results remained significant after adjusting for confounding factors, except for TC (P = 0.25).

CONCLUSIONS

The DASH diet was more effective than the control diet in managing fatty liver and cardiovascular risk factors.

TRIAL REGISTRATION

The trial was registered on 21 October 2022 at Iranian Registry of Clinical Trials (IRCT20180201038585N12, URL: https://irct.behdasht.gov.ir/trial/66161 ).

Fatty Liver Index (FLI) is the best score to predict MASLD with 50% lower cut-off value in women than in men

BACKGROUND

Metabolic dysfunction-associated steatotic liver disease (MASLD) is defined by the presence of hepatic steatosis, detected on ultrasonography (US) imaging or histology, and at least one of criteria for Metabolic Syndrome diagnosis. Simple non-invasive tests (NITs) have been proposed as an acceptable alternative when US and biopsy are not available or feasible but have not been validated for MASLD. In this observational study, we investigated the reliability of NITs for MASLD detection and whether sex-differences in screening methods should be considered.

METHODS

We included 1069 individuals (48% males and 52% females) who underwent their first clinical examination for Metabolic Syndrome in the period between January 2015 and December 2022. Liver steatosis was detected through US and anthropometric and clinical parameters were recorded.

RESULTS

Liver steatosis was detected in 648 patients and MASLD was diagnosed in 630 subjects (355 males; 275 females). Women with MASLD showed better metabolic profile and lower prevalence of Metabolic Syndrome criteria than men. Among NITs, Fatty Liver Index (FLI) showed the best ability for detection of MASLD, with a cut-off value of 44 (AUC = 0.82). When considering the two sexes for MASLD detection via FLI, despite no substantial differences regarding FLI correlations with metabolic biomarkers except for age, women showed marked lower FLI cut-off value (32; AUC = 0.80) than men (60; AUC = 0.80).

CONCLUSIONS

In this study, we found that FLI is the best non-invasive predictor of both liver steatosis and MASLD. The finding that in women FLI cut-off value for MASLD detection is 50% lower than in men suggests the need of a sex-specific personalized program of screening and prevention of dysmetabolism-related liver diseases, despite outwardly healthy biomarkers profile.

The Role of the Fatty Liver Index (FLI) in the Management of Non-Alcoholic Fatty Liver Disease: A Systematic Review

Currently, non-alcoholic fatty liver disease is the most common liver disease worldwide, with a prevalence of 32%. It is much more common among men (40%) and among patients with metabolic comorbidities such as obesity, diabetes and dyslipidemia. Being an asymptomatic disease, the diagnosis is often established on the basis of imaging methods, with an important role given to abdominal ultrasonography, computed tomography and magnetic resonance imaging. In order to facilitate diagnosis, experts have introduced a series of blood biomarkers. Two biomarker panels are currently validated for the diagnosis of non-alcoholic fatty liver disease: the fatty liver index, and the hepatic steatosis index. The fatty liver index has been in use in medical practice for over 17 years and has demonstrated its accuracy in various studies that compared it with other diagnostic methods, highlighted its role in screening patients with cardiovascular risk and validated the effects of different diets and drugs that are proposed for the treatment of the disease. In the management of non-alcoholic fatty liver disease, the fatty liver index is an important algorithm in the diagnosis and prognosis of patients with metabolic risk. Taking into account the diversity of drugs to be approved in the treatment of non-alcoholic fatty liver disease, the fatty liver index will become an effective tool in monitoring the effects of these therapies.

Utility of Indices Obtained during Medical Checkups for Predicting Fatty Liver Disease in Non-obese People

Objective To predict fatty liver disease (FLD), including nonalcoholic FLD (NAFLD) and metabolic dysfunction-associated FLD (MAFLD), from blood tests and anthropometric measurements, the fatty liver index (FLI) and triglyceride glucose-body mass index (TyG-BMI) have been reported as promising indicators. We evaluated the predictive ability of several indices, including the waist circumference, BMI, FLI and TyG-BMI, that might predict FLD in non-obese individuals undergoing health checkups. Methods This retrospective observational study enrolled non-obese subjects who underwent abdominal ultrasonography between May 1, 2015, and June 30, 2022. Obesity was defined as a BMI <25 kg/m2. FLD was diagnosed by abdominal ultrasonography. Using a receiver operating characteristic analysis, we examined the predictive validity of indices for NAFLD and MAFLD by calculating the area under the curve (AUC). Results Of the 24,825 subjects (mean age 44.3±10.0 years old; 54% men) enrolled in this examination of the association of indices, including FLI and TyG-BMI, with NAFLD, NAFLD was diagnosed in 3,619 (27%) men and 733 (6%) women. In both men and women, the FLI and TyG-BMI had significantly higher AUC values for NAFLD prediction than the other indicators (FLI: 0.786 for men and 0.875 for women, TyG-BMI: 0.783 for men and 0.868 for women). In analyses of subjects with a BMI <23 kg/m2, the superiority of the FLI and TyG-BMI remained unchanged. The FLI and TyG-BMI also had significantly higher AUC values for MAFLD prediction than the other indicators. Conclusion The FLI and TyG-BMI had a particularly high predictive ability for NAFLD and MAFLD in non-obese subjects.

Sugar-sweetened beverages, low/no-calorie beverages, fruit juice and non-alcoholic fatty liver disease defined by fatty liver index: the SWEET project

BACKGROUND

Sweetened beverage intake may play a role in non-alcoholic fatty liver disease (NAFLD) development, but scientific evidence on their role is limited. This study examined associations between sugar-sweetened beverages (SSB), low/no-calorie beverages (LNCB) and fruit juice (FJ) intakes and NAFLD in four European studies.

METHODS

Data for 42,024 participants of Lifelines Cohort, NQPlus, PREDIMED-Plus and Alpha Omega Cohort were cross-sectionally analysed. NAFLD was assessed using Fatty Liver Index (FLI) (≥60). Restricted cubic spline analyses were used to visualize dose-response associations in Lifelines Cohort. Cox proportional hazard regression analyses with robust variance were performed for associations in individual cohorts; data were pooled using random effects meta-analysis. Models were adjusted for demographic, lifestyle, and other dietary factors.

RESULTS

Each additional serving of SSB per day was associated with a 7% higher FLI-defined NAFLD prevalence (95%CI 1.03-1.11). For LNCB, restricted cubic spline analysis showed a nonlinear association with FLI-defined NAFLD, with the association getting stronger when consuming ≤1 serving/day and levelling off at higher intake levels. Pooled Cox analysis showed that intake of >2 LNCB servings/week was positively associated with FLI-defined NAFLD (PR 1.38, 95% CI 1.15-1.61; reference: non-consumers). An inverse association was observed for FJ intake of ≤2 servings/week (PR 0.92, 95% CI: 0.88-0.97; reference: non-consumers), but not at higher intake levels. Theoretical replacement of SSB with FJ showed no significant association with FLI-defined NAFLD prevalence (PR 0.97, 95% CI 0.95-1.00), whereas an adverse association was observed when SSB was replaced with LNCB (PR 1.12, 95% CI 1.03-1.21).

CONCLUSIONS

Pooling results of this study showed that SSB and LNCB were positively associated with FLI-defined NAFLD prevalence. Theoretical replacement of SSB with LNCB was associated with higher FLI-defined NAFLD prevalence. An inverse association was observed between moderate intake of FJ and FLI-defined NAFLD. Our results should be interpreted with caution as reverse causality cannot be ruled out.

Validation of nonalcoholic fatty liver disease (NAFLD) related steatosis indices in metabolic associated fatty liver disease (MAFLD) and comparison of the diagnostic accuracy between NAFLD and MAFLD

BACKGROUND

Metabolic-associated fatty liver disease (MAFLD) is a new term of nonalcoholic fatty liver disease (NAFLD), with newly proposed diagnostic criteria. The applicability of common noninvasive testing for screening NAFLD is unclear for the detection of MAFLD and requires reevaluation. We aimed to validate the effectiveness of traditional NAFLD-related steatosis indices for diagnosing MAFLD and to determine the optimal cutoff values as well as compare their accuracy between NAFLD and MAFLD diagnosis.

METHODS

This study enrolled 1866 participants from the National Health and Nutrition Examination Survey (NHANES) database (2017-2018). The diagnostic performances of fatty liver index (FLI), Framingham Steatosis Index (FSI), Zhejiang University index (ZJU), lipid accumulation product (LAP), hepatitis steatosis index (HSI) and visceral adiposity index (VAI) were evaluated using the area under the receiver operator characteristic (AUROC) curve and the optimal cutoff points were calculated according to maximum Youden's index.

RESULTS

FLI had the highest AUROC (0.840) for predicting MAFLD in the whole population, with a cutoff value of 56.93. The AUROCs of FLI, FSI, ZJU, LAP, HSI and VAI for predicting MAFLD/NAFLD were 0.840/0.812, 0.833/0.811, 0.826/0.811, 0.826/0.799, 0.814/0.803 and 0.747/0.729, respectively. The AUROC values of all indices decreased in the subgroup of the population with overweight or diabetes.

CONCLUSION

The NAFLD-related scores would be equally useful to screen MAFLD and seemed to be more compatible with MAFLD. The FLI was optimal in both MAFLD and NAFLD diagnoses. However, a new predictive indicator suitable for various characteristics of the population is worth further development in the future.

Assessing the clinical utility of major indices for nonalcoholic fatty liver disease in East Asian populations

Nonalcoholic fatty liver disease (NAFLD) is currently the most common form of chronic liver disease. The growing prevalence of NAFLD is strongly associated with the high incidence of metabolic syndrome. NAFLD affects as much as 19% of the US population with a disproportionate impact on minority racial groups such as Asian Americans. If not promptly managed, NAFLD may progress to more feared complications. Liver indices for NAFLD screening have been proposed but were often developed using study populations with different anthropometrics than patients of East Asian descent. This review compares the accuracy of five indices for NAFLD screening in Asian cohorts. The Fatty Liver Index performed well in multiple large-scale community studies, although other indices may be more suited for specific patient cohorts. This is important, as the utilization of liver indices could accelerate screening for NAFLD for early management and to reduce liver disease-related health disparities among Asian Americans.

Surveillance of the progression and assessment of treatment endpoints for nonalcoholic steatohepatitis

Nonalcoholic steatohepatitis (NASH) is an aggressive form of nonalcoholic fatty liver disease (NAFLD) characterized by steatosis-associated inflammation and liver injury. Without effective treatment or management, NASH can have life-threatening outcomes. Evaluation and identification of NASH patients at risk for adverse outcomes are therefore important. Key issues in screening NASH patients are the assessment of advanced fibrosis, differentiation of NASH from simple steatosis, and monitoring of dynamic changes during follow-up and treatment. Currently, NASH staging and evaluation of the effectiveness for drugs still rely on pathological diagnosis, despite sample error issues and the subjectivity associated with liver biopsy. Optimizing the pathological assessment of liver biopsy samples and developing noninvasive surrogate methods for accessible, accurate, and safe evaluation are therefore critical. Although noninvasive methods including elastography, serum soluble biomarkers, and combined models have been implemented in the last decade, noninvasive diagnostic measurements are not widely applied in clinical practice. More work remains to be done in establishing cost-effective strategies both for screening for at-risk NASH patients and identifying changes in disease severity. In this review, we summarize the current state of noninvasive methods for detecting steatosis, steatohepatitis, and fibrosis in patients with NASH, and discuss noninvasive assessments for screening at-risk patients with a focus on the characteristics that should be monitored at follow-up.

2019 Global NAFLD Prevalence: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

The increasing rates of obesity and type 2 diabetes mellitus may lead to increased prevalence of nonalcoholic fatty liver disease (NAFLD). We aimed to determine the current and recent trends on the global and regional prevalence of NAFLD.

METHODS

Systematic search from inception to March 26, 2020 was performed without language restrictions. Two authors independently performed screening and data extraction. We performed meta-regression to determine trends in NAFLD prevalence.

RESULTS

We identified 17,244 articles from literature search and included 245 eligible studies involving 5,399,254 individuals. The pooled global prevalence of NAFLD was 29.8% (95% confidence interval [CI], 28.6%-31.1%); of these, 82.5% of included articles used ultrasound to diagnose NAFLD, with prevalence of 30.6% (95% CI, 29.2%-32.0%). South America (3 studies, 5716 individuals) and North America (4 studies, 18,236 individuals) had the highest NAFLD prevalence at 35.7% (95% CI, 34.0%-37.5%) and 35.3% (95% CI, 25.4%-45.9%), respectively. From 1991 to 2019, trend analysis showed NAFLD increased from 21.9% to 37.3% (yearly increase of 0.7%, P < .0001), with South America showing the most rapid change of 2.7% per year, followed by Europe at 1.1%.

CONCLUSIONS

Despite regional variation, the global prevalence of NAFLD is increasing overall. Policy makers must work toward reversing the current trends by increasing awareness of NAFLD and promoting healthy lifestyle environments.

Triglyceride affects the association between estimated glomerular filtration rate and the onset of non-alcoholic fatty liver disease: A second analysis of a Chinese cohort study

Objective

The role of triglyceride (TG) and estimated glomerular filtration rate (eGFR) effect modifiers on the risk of non-alcoholic fatty liver disease (NAFLD) is unknown. This study examined whether TG modifies the relationship between eGFR and incident NAFLD.

Methods

In a Chinese hospital from January 2010 to December 2014, 15,555 non-obese subjects were collected systematically for this retrospective cohort study. The target-independent and dependent variables were eGFR measured at baseline and NAFLD appearing during follow-up. The modified variable was TG measured at baseline. The multivariate Cox proportional hazards model was used to explore eGFR and TG’s association with NAFLD risk. We explored a priori interaction between eGFR and TG, and performed subgroup analyses to further assess whether the relationship between eGFR and incident NAFLD was modified by TG. We also explored the effect of TG and eGFR interaction on the risk of NAFLD.

Results

The mean age was 43.09 ± 14.92 years, and 8,131 (52.27%) were males. During a median follow-up time of 35.8 months, 2,077 (13.35%) individuals developed NAFLD. In the adjusted model, eGFR was negatively associated with incident NAFLD (HR = 0.984, 95% CI: 0.982, 0.987), while TG was positively related to NAFLD (HR = 1.582, 95% CI: 1.490, 1.681). TG could modify the relationship between eGFR and incident NAFLD. A stronger association between eGFR and NAFLD could be found in the participants without hypertriglyceridemia (HTG) (HR = 0.981, 95% CI: 0.978–0.984, P for interaction = 0.0139). In contrast, the weaker association was probed in the population with HTG (HR = 0.986, 95% CI: 0.983–0.989). At the same time, we also found an interaction between eGFR and TG in influencing NAFLD risk. In participants with decreased eGFR and HTG, the risk of NAFLD was significantly increased. Further, compared to non-HTG subjects with eGFR ≥ 116.56 ml/min/1.73 m², participants with HTG and eGFR < 82.88 ml/min/1.73 m² had about a fourfold increase in the risk (HR = 4.852 95% CI: 3.943–5.970) of NAFLD.

Conclusion

eGFR and TG is independently associated with NAFLD risk. The association of eGFR with incident NAFLD is likely to be modified by TG in the Chinese non-obese population. There was an interactive effect between eGFR and TG in affecting NAFLD risk. In participants with decreased eGFR and hypertriglyceridemia, the risk of NAFLD is significantly increased.

The triglyceride glucose-body mass index: a non-invasive index that identifies non-alcoholic fatty liver disease in the general Japanese population

Background

By identifying individuals at high risk for non-alcoholic fatty liver disease (NAFLD), interventional programs could be targeted more effectively. Some studies have demonstrated that triglyceride glucose-body mass index (TyG-BMI) showed an independent positive association with NAFLD. However, research on its diagnostic value in patients with suspected NAFLD is limited. In this study, we aimed to evaluate whether TyG-BMI was accurate in detecting NAFLD in the general Japanese population.

Methods

A cross-sectional study of 14,280 individuals who underwent a comprehensive health examination was conducted. Standard protocols were followed to collect anthropometric measurements, lab data, and ultrasonography features. All participants were randomly stratified into the development group (n = 7118) and validation group (n = 7162). The TyG-BMI was calculated. Following this, the diagnostic value of the TyG-BMI was evaluated based on the area under the receiver-operating characteristic curve (AUROC). Two cutoff points were selected and used to rule out or rule in the NALFD, and the specificity, sensitivity, negative predictive value, and positive predictive value were explored, respectively. In order to verify the stability of the results, external verification was performed.

Results

There were 1272 and 1243 NAFLD participants in the development and validation groups, respectively. The area under the ROC curve (AUC) of TyG-BMI was 0.888 (95% CI 0.876–0.896) and 0.884 (95% CI 0.875–0.894) for the training and validation group, respectively. Using the low TyG-BMI (182.2) cutoff, NAFLD could be excluded with high accuracy (negative predictive value: 96.9% in estimation and 96.9% in validation). The presence of NAFLD could effectively be determined by applying the high cutoff of TyG-BMI (224.0), as the positive predictive value of the estimation and validation groups is 70.7% and 70.1%, respectively. As a result of applying this model, 9996 (70%) of the 14,280 participants would not have undergone ultrasonography, with an accurate prediction of 9308 (93.1%). AUC was 0.874 for external validation using 183,730 Chinese non-obese participants. TyG-BMI was demonstrated to be an excellent diagnostic tool by both internal and external validation.

Conclusions

In conclusion, the present study developed and validated a simple, non-invasive, and cost-effective tool to accurately separate participants with and without NAFLD in the Japanese population, rendering ultrasonography for identifying NAFLD unnecessary in a substantial proportion of people.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03611-4.

External validation and comparison of simple tools to screen for nonalcoholic fatty liver disease in Chinese community population

BACKGROUND

Various noninvasive tools based on anthropometric indicators, blood lipids, and liver enzymes, etc. have been developed to screen for nonalcoholic fatty liver disease (NAFLD), with different diagnostic performance and cutoff values among studies. We aimed to validate and compare eight NAFLD-related models developed by simple indicators and to define their cutoff values in Chinese community population.

METHODS

A cross-sectional study was conducted in a health examination cohort of 3259 people. NAFLD was diagnosed by ultrasonography. General, anthropometric and biochemical data were collected. Fatty liver index (FLI), fatty liver disease index (FLD), Zhejiang University index (ZJU), lipid accumulation product (LAP), regression formula of controlled attenuation parameter (CAP), waist-to-height ratio (WHtR), triglyceride and glucose index (TyG), and visceral adiposity index (VAI) were calculated. The accuracy and cutoff points to detect NAFLD were evaluated by area under the receiver operator characteristic curve and the maximum Youden index analysis, respectively. A head-to-head comparison between these models and Decision Curve Analysis (DCA) was conducted.

RESULTS

In eight noninvasive diagnostic models of NAFLD, AUCs of FLI and FLD for NAFLD were higher than those of other models in the whole (0.852 and 0.852), male (0.826 and 0.824), and female (0.897 and 0.888) population, respectively. DCA showed that FLI, FLD, and ZJU have higher net benefit to screen for NAFLD compared to other models.

CONCLUSIONS

FLI and FLD could be the most accurate and applicable of eight models for the noninvasive diagnosis of NAFLD in both male and female groups.

Comparison of the Diagnostic Performance of Steatosis Indices for Discrimination of CT-Diagnosed Metabolic Dysfunction-Associated Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) was redefined as metabolic dysfunction-associated fatty liver disease (MAFLD) in 2020. Due to this, further validation of the non-invasive tests used in NAFLD diagnosis is required for MAFLD. There are five known steatosis indices for computed tomography (CT)-diagnosed MAFLD. These indices include the fatty liver index (FLI), the hepatic steatosis index (HSI), the lipid accumulation product (LAP), the visceral adiposity index (VAI), and the Zhejiang University index (ZJU). We aimed to analyze the diagnostic abilities of these five widely known steatosis indices for CT-diagnosed MAFLD. From March 2012 to October 2019, we retrospectively analyzed the clinical information and images of 1300 adults aged ≥19 years who underwent CT scans at our institution. To compare differences, the Chi-square test and independent t-test were used for categorical and continuous variables, respectively. The area under the receiver operating characteristic (AUROC) curve was used to validate the diagnostic accuracy of MAFLD. Of the five indices, FLI was the best at predicting MAFLD, with the highest AUROC (0.791). The sensitivity and specificity of FLI for diagnosing MAFLD were both 70.9%. The optimal cut-off value was 29.9. FLI is a useful surrogate index for screening MAFLD in clinical practice.

Prediction and validation of nonalcoholic fatty liver disease by fatty liver index in a Japanese population

Fatty liver index (FLI) calculated by using body mass index (BMI), waist circumference and levels of γ-glutamyl transferase and triglycerides is a non-invasive predictor of nonalcoholic fatty liver disease (NAFLD). The original study in Italy showed that the cutoff level for prediction of NAFLD was FLI ≥60. However, the sex difference in FLI was not taken into consideration, and it is unclear whether the cutoff value can be applied to other races. We investigated the cutoff value of FLI for prediction of NAFLD determined by abdominal ultrasonography using receiver operating characteristic curve analyses in 14,471 Japanese subjects (men/women: 9,240/5,231; mean age: 48 ± 9 years). There was a significant interaction between sex and FLI for detection of NAFLD (p < 0.001). The cutoff values of FLI in men and women were 35.1 (area under the curve [AUC]: 0.82) and 15.6 (AUC: 0.91), respectively. When the subjects were divided by the absence and presence of obesity (BMI ≥25), there was a significant interaction between FLI and obesity for detection of NAFLD in women (p < 0.001) but not in men (p = 0.679). The cutoff values of FLI in non-obese/obese men and women were 22.6/52.6 and 11.2/33.2, respectively. In conclusion, the cutoff value of FLI for prediction of NAFLD in Japanese individuals was lower than that in the original study, and there is a significant sex difference. The simple and useful cutoff values in Japanese men and women are FLI ≥35 (non-obese/obese: 23/53) and FLI ≥16 (non-obese/obese: 11/33), respectively.

Long-term exposure to air pollution, habitual physical activity and risk of non-alcoholic fatty liver disease: A prospective cohort study

BACKGROUND

Emerging studies suggest a positive association between air pollution exposure and risk of non-alcoholic fatty liver disease (NAFLD), however, the combined effects of long-term exposure to air pollution, physical activity (PA), and risk of NAFLD is unclear.

METHODS

We included 58,026 Taiwan residents who received a standard medical screening program between 2001 and 2016. Levels of fine particulate matter (PM_2.5) at each participant's residential address were estimated using multiple satellite-based aerosol optical depth data combined with a chemical transport model. PA volume was calculated as hours of metabolic equivalent tasks per week (MET-h/week) based on a standard self-administered questionnaire. Incident NAFLD was defined as the first occurrence of a fatty liver index (FLI) value > 30 or a hepatic steatosis index (HSI) value > 36 in participants without NAFLD at the baseline. Time-varying Cox regression was used to evaluate the combined effects of PA and PM_2.5.

RESULTS

Exposure to PM_2.5 was positively associated with NAFLD. A 1 μg/m³ increase in PM_2.5 above 23.5 μg/m³ was associated with a hazard ratio (HR) of 1.06 (95% CI: 1.04, 1.09) and 1.05 (95% CI: 1.03, 1.07) for NAFLD identified by FLI and HSI, respectively. Performing PA was inversely associated with NAFLD. Compared with participants in high PM_2.5 [≥ 27.5 μg/m³]-very low PA [< 3.75 MET-h/week] group, low PM_2.5 [< 23.5 μg/m³]-very high PA [≥ 25.50 MET-h/week] group had a 57% (95% CI: 50%, 63%) and 42% (95% CI: 33%, 50%) lower risk of NAFLD defined by FLI and HSI, respectively. We found no evidence of any additive or multiplicative interaction between PA and PM_2.5.

CONCLUSION

Long-term PM_2.5 exposure was positively associated with NAFLD, whereas performing PA was inversely associated with NAFLD. The benefits of PA on NAFLD remained stable in participants exposed to various PM_2.5 levels.

Diagnostic significance of clinical and laboratory indices in predicting non-alcoholic fatty liver disease during screening studies

Aim. To study the significance of clinical and laboratory non-invasive indexes along with the insulin resistance index when carrying out diagnostic assessment of non-alcoholic fatty liver disease (NAFLD) during screening examinations. Materials and methods. The study involved 348 employees working at oil-production enterprises. An ultrasound scanning of the liver was carried out to assess the criteria of NAFLD. The following indexes were calculated: fatty liver index (FLI), hepatic steatosis index (HSI), lipid accumulation products (LAP), and homeostasis model assessment of insulin resistance (HOMA1-IR). The prognostic significance of these indexes in relation to the probability of NAFLD diagnosis based on ultrasound data was studied using single-factor and multi-factor logistic regression models followed by ROC-analysis. Results. The FLI, HSI, and HOMA1-IR indexes in single-factor logistic regression models showed a high statistical significance when carrying out diagnostic assessment the NAFLD with good model calibration capability. The percentage of correct binary classification regards the presence/absence of NAFLD amounted to 82.4% for FLI, 79.7% for HSI, and 72.7% for HOMA1-IR (p0.001). According to the ROC-analysis, the area under the curve (AUC) by the NAFLD diagnostic assessment was 0.917 (95% CI 0.8890.945); 0.880 (95% CI 0.8460.915) and 0.849 (95% CI 0.7640.934), respectively. The multi-factor logistic regression model with the inclusion of FLI and HOMA1-IR 72.7% enabled us to achieve the correct binary classification in terms of NAFLD in 84.2% of cases. When it comes to the ROC-analysis, considering the probabilities predicted in the multi-factor logistic model as the test variable and NAFLD in ultrasound examination as the state variable, it was possible to set the value of AUC 0.933 (95% CI 0.8820.985). Conclusion. The studied clinical and laboratory indexes (FLI, HSI, HOMA1-IR) have a high diagnostic significance regarding NAFLD diagnosed using ultrasonographic criteria. The application of the proposed two-factor logistics model makes it possible to predict the presence of NAFLD when examining a large number of patients, without involving additional ultrasound diagnostics specialists in order to use medical resources rationally.

Effect of omega-3 supplementation on fatty liver and visceral adiposity indices in diabetic patients with non-alcoholic fatty liver disease: A randomized controlled trial

BACKGROUND AND AIMS

Non-alcoholic fatty liver disease (NAFLD) as the most common chronic liver disease is closely linked to type 2 diabetes mellitus (T2DM). Omega-3 supplementation has been proposed as a strategy to manage T2DM and NAFLD. The present study aimed to investigate the effect of omega-3 supplementation on fatty liver index, lipid accumulation product and visceral adiposity index in diabetic patients with NAFLD.

METHODS

In this 12-week double-blind, randomized controlled clinical trial, sixty diabetic patients with NAFLD were randomly assigned into the omega-3 and placebo groups for 12 weeks. The omega-3 group received 2000 mg/d omega-3 as capsule.

RESULTS

Fifty-six participants completed the study. No significant difference was found between the two groups in the terms of fatty liver index, lipid accumulation product and visceral adiposity index at the baseline. Omega-3 supplementation compared with the placebo led to a significant improvement in fatty liver index (-3.6 ± 12.1 vs. 0.9 ± 8.9; P = 0.04), lipid accumulation product (-14.2 ± 27.9 vs. 8.0 ± 26.3; P = 0.002) and visceral adiposity index (-0.5 ± 0.9 vs. 0.0 ± 0.8; P = 0.01).

CONCLUSION

Omega-3 supplementation for 12 weeks improves fatty liver index, lipid accumulation product and visceral adiposity index. The study protocol was registered under Iranian Registry of Clinical Trials identifier number IRCT2016102530489N1.

Nine Markers to Predict Nonalcoholic Fatty Liver Disease for a Chinese Diabetic Population

Background: Nonalcoholic fatty liver disease (NAFLD) increases the possibility to suffer from liver or cardiovascular disease. Although hepatic biopsy is well acknowledged as the standard diagnosis, it is difficult to implement because of its intrusiveness and cost concerns. Moreover, overweight people or diabetic patients are always NAFLD-positive, but not absolute. Therefore, to distinguish whether a diabetic case has NAFLD via nonintrusive indicators is of great significance for further interventions. Objective: With 8499 diabetic patients hosted by Shanghai Sixth People’s Hospital, we try to rank the impacts of multiple routine indicators (features) on NAFLD, and further predict NAFLD within this diabetic population. Methods: We first rank dozens of related features according to their contributions in NAFLD prediction, and then we prune several trivial features to simplify the prediction. Additionally, three classification algorithms are considered and compared, e.g., C4.5, Naïve Bayes and Random Forest. Results: The experiment shows that Random Forest outperforms the rest (accuracy 85.1%, recall 90.98% and AUC 0.631). Conclusions: We find that the top nine markers together can effectively tell NAFLD out of this diabetic population. They are triglyceride (TG), low density lipoprotein (LDL), insulin (INS), hbA1C, high-density lipoprotein (HDL), fasting plasma glucose (FPG), age, total cholesterol (TC) and duration.

Epidemiology: Pathogenesis, and Diagnostic Strategy of Diabetic Liver Disease in Japan

Type 2 diabetes (T2D) is closely associated with nonalcoholic fatty liver disease (NAFLD). Nonalcoholic steatohepatitis (NASH), a severe form of NAFLD, can lead to cirrhosis, hepatocellular carcinoma (HCC), and hepatic decompensation. Patients with T2D have twice the risk of HCC incidence compared with those without T2D. Because the hepatic fibrosis grade is the main determinant of mortality in patients with NAFLD, identifying patients with advanced fibrosis using non-invasive tests (NITs) or imaging modalities is crucial. Globally, the fibrosis-4 index (FIB-4 index), NAFLD fibrosis score, and enhanced liver fibrosis test have been established to evaluate hepatic fibrosis. Two-step algorithms using FIB-4 index as first triaging tool are globally accepted. It remains unknown which kinds of NITs or elastography are best as the second step tool. In Japan, type IV collagen 7s or the CA-fibrosis index (comprising type IV collagen 7s and aspartate aminotransferase (AST)) is believed to precisely predict advanced fibrosis in NAFLD. Patients with NAFLD who have high non-invasive test results should be screened for HCC or esophageal varices. Risk factors of rapid fibrosis progression in NAFLD includes age, severe obesity, presence of T2D, menopause in women, and a patatin-like phospholipase domain containing the 3 GG genotype. Patients with NAFLD who have these risk factors should be intensively treated with lifestyle modification or pharmacotherapies for preventing liver-related mortality.

Validation of fatty liver index and hepatic steatosis index for screening of non-alcoholic fatty liver disease in adults with obstructive sleep apnea hypopnea syndrome

Background:

Obstructive sleep apnea hypopnea syndrome (OSAHS) is a contributing factor for non-alcoholic fatty liver disease (NAFLD). Non-invasive algorithms including fatty liver index (FLI) and hepatic steatosis index (HSI) have been used as a screening test for NAFLD in epidemiologic studies. The aim of this study is to compare the diagnostic accuracy of FLI and HSI for NAFLD detection in adults with OSAHS.

Methods:

We enrolled consecutive adult subjects who were newly diagnosed with OSAHS from March 2016 to January 2018. NAFLD was diagnosed by ultrasonography. The accuracy and cut-off point of the FLI and HSI to detect NAFLD were assessed by analyzing the area under the receiver operating characteristic (AUROC) curve and the maximum Youden index analysis, respectively.

Results:

The 326 subjects were diagnosed as NAFLD according to ultrasound findings, while 105 subjects who had normal abdominal ultrasonography were grouped as controls. Both FLI and HSI values were significantly higher in patients with NAFLD compared with controls. The AUROC of FLI and HSI for predicting NAFLD was 0.802 (95% confidence interval [CI] 0.762–0.839) and 0.753 (95% CI 0.710–0.793), respectively. The AUROC of FLI was significantly higher than that of HSI (P = 0.0383). The optimal cut-off value of FLI and HSI was 60 (sensitivity 66% and specificity 80%) and 35 (sensitivity 81% and specificity 60%), respectively.

Conclusions:

Both FLI and HSI can serve as screening tools for NAFLD in OSAHS adults. The FLI shows better performance in diagnosing NAFLD than HSI.

Trial registration:

Chinese Clinical Trial Registry (No. ChiCTR-OOB-15007253), http://www.chictr.org.cn/showproj.aspx?proj=11606.

Associations Between Body Fat, Muscle Mass, and Nonalcoholic Fatty Liver Disease: A Population-Based Study

Nonalcoholic fatty liver disease (NAFLD) is one of the most common forms of liver disease worldwide and has emerged as a significant public health concern in China. A better understanding of the etiology of NAFLD can inform effective management strategies for this disease. We examined factors associated with NAFLD in two districts of Hangzhou, China, focusing on the relationship of regional body fat distribution, muscle mass, and NAFLD. We used baseline data to carry out a cross‐sectional analysis among 3,589 participants from the Wellness Living Laboratory (WELL) China study, a longitudinal population‐based study that aims to investigate and promote well‐being among the Chinese population. NAFLD was defined using the widely validated fatty liver index (FLI). Multivariate logistic regressions were performed to assess independent associations between NAFLD and metabolic risk factors (e.g., insulin resistance) and dual x‐ray absorptiometry (DXA)‐derived measures (e.g., android fat ratio [AFR] and skeletal muscle index [SMI]). Of the 3,589 participants, 476 (13.3%) were classified as having FLI‐defined NAFLD (FLI ≥60). Among those, 58.0% were men. According to our analysis, AFR (odds ratio [OR], 10.0; 95% confidence interval [CI], 5.8‐18.5), insulin resistance (OR, 4.0; 95% CI, 3.0‐5.3), high alanine aminotransferase levels (OR, 7.6; 95% CI, 5.8‐10.0), smoking (OR, 2.0; 95% CI, 1.4‐3.0), and male sex (OR, 2.9; 95% CI, 2.0‐4.2) were positively associated with NAFLD risk, while SMI (OR, 0.1; 95% CI, 0.07‐0.13) was inversely associated with NAFLD risk. Conclusion: In addition to known metabolic risk factors, DXA‐derived AFR and SMI may provide additional insights to the understanding of NAFLD. Interventions that aim to decrease AFR and increase SMI may be important to reduce the burden of NAFLD in this population.

Noninvasive evaluation of nonalcoholic fatty liver disease: Current evidence and practice

With the increasing number of individuals with diabetes and obesity, nonalcoholic fatty liver disease (NAFLD) is becoming increasingly prevalent, affecting one-quarter of adults worldwide. The spectrum of NAFLD ranges from simple steatosis or nonalcoholic fatty liver (NAFL) to nonalcoholic steatohepatitis (NASH). NAFLD, especially NASH, may progress to fibrosis, leading to cirrhosis and hepatocellular carcinoma. NAFLD can impose a severe economic burden, and patients with NAFLD-related terminal or deteriorative liver diseases have become one of the main groups receiving liver transplantation. The increasing prevalence of NAFLD and the severe outcomes of NASH make it necessary to use effective methods to identify NAFLD. Although recognized as the gold standard, biopsy is limited by its sampling bias, poor acceptability, and severe complications, such as mortality, bleeding, and pain. Therefore, noninvasive methods are urgently needed to avoid biopsy for diagnosing NAFLD. This review discusses the current noninvasive methods for assessing NAFLD, including steatosis, NASH, and NAFLD-related fibrosis, and explores the advantages and disadvantages of measurement tools. In addition, we analyze potential noninvasive biomarkers for tracking disease processes and monitoring treatment effects, and explore effective algorithms consisting of imaging and nonimaging biomarkers for diagnosing advanced fibrosis and reducing unnecessary biopsies in clinical practice.