AIMS: To provide a narrative review on the performance and limitations of non-invasive tests, with a special emphasis on the impact of diabetes and obesity.

METHODS: We searched PubMed and Cochrane databases for articles published from 1990 to August 2023.

RESULTS: Abdominal ultrasonography remains the primary method to diagnose hepatic steatosis, while magnetic resonance imaging proton density fat fraction is currently the gold standard to quantify steatosis. Simple fibrosis scores such as the Fibrosis-4 index are well suited as initial assessment in primary care and non-hepatology settings to rule out advanced fibrosis and future risk of liver-related complications. However, because of its low positive predictive value, an abnormal test should be followed by specific blood (e.g. Enhanced Liver Fibrosis score) or imaging biomarkers (e.g. vibration-controlled transient elastography and magnetic resonance elastography) of fibrosis. Some non-invasive tests of fibrosis appear to be less accurate in patients with diabetes. Obesity also affects the performance of abdominal ultrasonography and transient elastography, whereas magnetic resonance imaging may not be feasible in some patients with severe obesity.

AIMS: To determine the prevalence of alcohol abstinence, factors associated with alcohol abstinence and the impact of abstinence on morbidity and overall survival in people with alcohol-associated cirrhosis.

METHODS: We searched Medline and Embase from inception to 15 April 2023 for prospective and retrospective cohort studies describing alcohol abstinence in people with known alcohol-associated cirrhosis. Meta-analysis of proportions for pooled estimates was performed. The method of inverse variance, employing a random-effects model, was used to pool the hazard ratio (HR) comparing outcomes of abstinent against non-abstinent individuals with alcohol-associated cirrhosis.

RESULTS: We included 19 studies involving 18,833 people with alcohol-associated cirrhosis. The prevalence of alcohol abstinence was 53.8% (CI: 44.6%-62.7%). Over a mean follow-up duration of 48.6 months, individuals who continued to consume alcohol had significantly lower overall survival compared to those who were abstinent (HR: 0.611, 95% CI: 0.506-0.738). These findings remained consistent in sensitivity/subgroup analysis for the presence of decompensation, study design and studies that assessed abstinence throughout follow-up. Alcohol abstinence was associated with a significantly lower risk of hepatic decompensation (HR: 0.612, 95% CI: 0.473-0.792).

METHODS: Search was conducted on Medline and Embase for meta-analysis investigating associated complications and causes of mortality in NAFLD patients. Summary estimates were presented with original units, sample size, and I2 for heterogeneity. The Assessment of Multiple Systematic Reviews 2 was employed for article selection.

RESULTS: 25 meta-analyses were included in the present review. NAFLD increased the risks of systemic complications, including cardiovascular diseases, systemic malignancies, diabetes, and chronic kidney disease. Regarding hepatic outcomes, the incidence of hepatocellular carcinoma in NAFLD was 2.39 per 100 person years (CI: 1.40 to 4.08). Individuals with NAFLD were also found to have an increased likelihood of cholangiocarcinoma (OR: 1.88, CI: 1.25 to 2.83) and gallstone disease (OR: 1.55, CI: 1.31 to 1.82) compared to individuals without NAFLD. NAFLD was associated with a higher risk of fatal and non-fatal CVD events (HR: 1.45, CI: 1.31 to 1.61) compared to individuals without NAFLD. Coronary heart disease and subclinical and clinical coronary heart disease were also significantly elevated in NAFLD individuals compared to individuals without NAFLD. Additionally, NAFLD was associated with an increased risk of all-cause mortality (HR: 1.34, CI: 1.17 to 1.54) and cardiovascular (HR: 1.30, CI: 1.08 to 1.56) but not cancer-related mortality.

METHODS: The analysis consisted of adults in the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2018 with data on socio-demographic characteristics and comorbidities. NAFLD was diagnosed with fatty liver index (FLI) and United States-FLI at a cut-off of 60 and 30, respectively in the substantial absence of alcohol use. A multivariate regression analysis was conducted to adjust for confounders.

RESULTS: A total of 45,302 adults were included, and 27.83% were identified to have NAFLD. Overall, 45.65 and 35.12% of patients with NAFLD had HTN and uncontrolled HTN, respectively. A multivariate analysis with confounders demonstrated that hypertensive NAFLD had a significantly increased risk of all-cause mortality (HR: 1.39, CI: 1.14-1.68, p < 0.01) and cardiovascular disease (CVD) mortality (HR: 1.85, CI: 1.06-3.21, p = 0.03). Untreated HTN remained to have a significantly increased risk in all-cause (HR: 1.59, CI: 1.28-1.96, p < 0.01) and CVD mortality (HR: 2.36, CI: 1.36-4.10, p < 0.01) while treated HTN had a non-significant increased risk of CVD mortality (HR: 1.51, CI: 0.87-2.63, p = 0.14) and a lower magnitude of increase in the risk of all-cause mortality (HR: 1.26, CI: 1.03-1.55, p = 0.03).

METHODS: This was an individual participant data meta-analysis for the performance of NITs against liver biopsy for MASH+F2-4, MASH+F2-3 and MASH+F4. Index tests were the FibroScan-AST (FAST) score, liver stiffness measured using vibration-controlled transient elastography (LSM-VCTE), the fibrosis-4 score (FIB-4) and the NAFLD fibrosis score (NFS). Area under the receiver operating characteristics curve (AUROC) and thresholds including those that achieved 34% SFR were reported.

RESULTS: We included 2281 unique cases. The prevalence of MASH+F2-4, MASH+F2-3 and MASH+F4 was 31%, 24% and 7%, respectively. Area under the receiver operating characteristics curves for MASH+F2-4 were .78, .75, .68 and .57 for FAST, LSM-VCTE, FIB-4 and NFS. Area under the receiver operating characteristics curves for MASH+F2-3 were .73, .67, .60, .58 for FAST, LSM-VCTE, FIB-4 and NFS. Area under the receiver operating characteristics curves for MASH+F4 were .79, .84, .81, .76 for FAST, LSM-VCTE, FIB-4 and NFS. The sequential combination of FIB-4 and LSM-VCTE for the detection of MASH+F2-3 with threshold of .7 and 3.48, and 5.9 and 20 kPa achieved SFR of 67% and sensitivity of 60%, detecting 15 true positive cases from a theoretical group of 100 participants at the prevalence of 24%.

METHODS: This was an individual participant data meta-analysis of the prognostic performance of histologically assessed fibrosis stage (F0-4), liver stiffness measured by vibration-controlled transient elastography (LSM-VCTE), fibrosis-4 index (FIB-4), and NAFLD fibrosis score (NFS) in patients with NAFLD. The literature was searched for a previously published systematic review on the diagnostic accuracy of imaging and simple non-invasive tests and updated to Jan 12, 2022 for this study. Studies were identified through PubMed/MEDLINE, EMBASE, and CENTRAL, and authors were contacted for individual participant data, including outcome data, with a minimum of 12 months of follow-up. The primary outcome was a composite endpoint of all-cause mortality, hepatocellular carcinoma, liver transplantation, or cirrhosis complications (ie, ascites, variceal bleeding, hepatic encephalopathy, or progression to a MELD score ≥15). We calculated aggregated survival curves for trichotomised groups and compared them using stratified log-rank tests (histology: F0-2 vs F3 vs F4; LSM: <10 vs 10 to <20 vs ≥20 kPa; FIB-4: <1·3 vs 1·3 to ≤2·67 vs >2·67; NFS: 0·676), calculated areas under the time-dependent receiver operating characteristic curves (tAUC), and performed Cox proportional-hazards regression to adjust for confounding. This study was registered with PROSPERO, CRD42022312226.

FINDINGS: Of 65 eligible studies, we included data on 2518 patients with biopsy-proven NAFLD from 25 studies (1126 [44·7%] were female, median age was 54 years [IQR 44-63), and 1161 [46·1%] had type 2 diabetes). After a median follow-up of 57 months [IQR 33-91], the composite endpoint was observed in 145 (5·8%) patients. Stratified log-rank tests showed significant differences between the trichotomised patient groups (p<0·0001 for all comparisons). The tAUC at 5 years were 0·72 (95% CI 0·62-0·81) for histology, 0·76 (0·70-0·83) for LSM-VCTE, 0·74 (0·64-0·82) for FIB-4, and 0·70 (0·63-0·80) for NFS. All index tests were significant predictors of the primary outcome after adjustment for confounders in the Cox regression.

INTERPRETATION: Simple non-invasive tests performed as well as histologically assessed fibrosis in predicting clinical outcomes in patients with NAFLD and could be considered as alternatives to liver biopsy in some cases.