Validation of AGA clinical care pathway and AASLD practice guidance for nonalcoholic fatty liver disease in a prospective cohort of patients with type 2 diabetes.

BACKGROUND AND AIMS: Recently, the American Gastroenterological Association and the American Association for the Study of Liver Diseases developed clinical pathways to evaluate populations at high risk for NAFLD. We assessed the diagnostic performance of the new guidance in a well-phenotyped cohort of patients with Type 2 diabetes mellitus (T2DM). APPROACH AND RESULTS: This prospective study enrolled patients age ≥50 years with T2DM. Participants underwent a standardized clinical research visit with MRI and ultrasound-based assessment of liver fat and stiffness and Enhanced Liver Fibrosis (ELF) testing. Of 417 participants (36% men) with T2DM with FIB-4 and MRE data, the prevalence of NAFLD was 64% and 12% had advanced fibrosis (MRE≥3.63 kPa). Applying the American Gastroenterological Association pathway of FIB-4 and vibration-controlled transient elastography, the false negative rate was 3.3% and 18% would qualify for specialty referral. Applying the FIB-4 + ELF American Association for the Study of Liver Diseases pathway, the false negative rate was 4.5%, but 50% would qualify for specialty referral. Applying higher ELF cut points improved the pathway, yielding a similar false negative rate of 4.9% but decreased specialty referral to 27%. CONCLUSION: Validation of the American Gastroenterological Association clinical pathway in a prospectively recruited cohort with T2DM revealed a low false negative rate and avoided specialty referral in a large percentage of patients. The American Association for the Study of Liver Diseases pathway with FIB-4 + ELF resulted in a high rate of specialty referral, which improved with the utilization of higher ELF cut points and may serve as an alternative for primary care and endocrinology clinics without access to vibration-controlled transient elastography.

MASH Resolution Index: development and validation of a non-invasive score to detect histological resolution of MASH.

BACKGROUND: Dynamic changes in non-invasive tests, such as changes in alanine aminotransferase (ALT) and MRI proton-density-fat-fraction (MRI-PDFF), may help to detect metabolic dysfunction-associated steatohepatitis (MASH) resolution, but a combination of non-invasive tests may be more accurate than either alone. We developed a novel non-invasive score, the MASH Resolution Index, to detect the histological resolution of MASH. METHODS: This study included a derivation cohort of 95 well-characterised adult participants (67% female) with biopsy-confirmed MASH who underwent contemporaneous laboratory testing, MRI-PDFF and liver biopsy at two time points. The primary objective was to develop a non-invasive score to detect MASH resolution with no worsening of fibrosis. The most predictive logistic regression model was selected based on the highest area under the receiver operating curve (AUC), and the lowest Akaike information criterion and Bayesian information criterion. The model was then externally validated in a distinct cohort of 163 participants with MASH from a clinical trial. RESULTS: The median (IQR) age and body mass index were 55 (45-62) years and 32.0 (30-37) kg/m2, respectively, in the derivation cohort. The most accurate model (MASH Resolution Index) included MRI-PDFF, ALT and aspartate aminotransferase. The index had an AUC of 0.81 (95% CI 0.69 to 0.93) for detecting MASH resolution in the derivation cohort. The score calibrated well and performed robustly in a distinct external validation cohort (AUC 0.83, 95% CI 0.76 to 0.91), and outperformed changes in ALT and MRI-PDFF. CONCLUSION: The MASH Resolution Index may be a useful score to non-invasively identify MASH resolution.

A prospective study on the prevalence of NAFLD, advanced fibrosis, cirrhosis and hepatocellular carcinoma in people with type 2 diabetes.

BACKGROUND & AIMS: There are limited prospective data on patients with type 2 diabetes mellitus (T2DM) specifically enrolled and systematically assessed for advanced fibrosis or cirrhosis due to non-alcoholic fatty liver disease (NAFLD). Therefore, we aimed to evaluate the prevalence of advanced fibrosis and cirrhosis in a prospectively recruited cohort of adults with T2DM. METHODS: This prospective study enrolled adults aged ≥50 years with T2DM, recruited from primary care or endocrinology clinics. Participants underwent a standardized clinical research visit with MRI-proton density fat fraction (MRI-PDFF), magnetic resonance elastography (MRE), vibration-controlled transient elastography (VCTE) and controlled-attenuation parameter. NAFLD was defined as MRI-PDFF ≥5% after exclusion of other liver diseases. Advanced fibrosis and cirrhosis were defined by established liver stiffness cut-off points on MRE or VCTE if MRE was not available. RESULTS: Of 524 patients screened, 501 adults (63% female) with T2DM met eligibility. The mean age and BMI were 64.6 (±8.1) years and 31.4 (±5.9) kg/m2, respectively. The prevalence of NAFLD, advanced fibrosis and cirrhosis was 65%, 14% and 6%, respectively. In multivariable adjusted models, adjusted for age and sex, obesity and insulin use were associated with increased odds of advanced fibrosis (odds ratio 2.50; 95% CI 1.38-4.54; p = 0.003 and odds ratio 2.71; 95% CI 1.33-5.50; p = 0.006, respectively). Among 29 patients with cirrhosis, two were found to have hepatocellular carcinoma and one patient had gallbladder adenocarcinoma. CONCLUSION: Utilizing a uniquely well-phenotyped prospective cohort of patients aged ≥50 years with T2DM, we found that the prevalence of advanced fibrosis was 14% and that of cirrhosis was 6%. These data underscore the high risk of advanced fibrosis/cirrhosis in adults aged ≥50 years with T2DM. IMPACT AND IMPLICATIONS: Non-alcoholic fatty liver disease (NAFLD) is common in patients with type 2 diabetes (T2DM), however, there are limited prospective data characterizing the prevalence of advanced fibrosis and cirrhosis using the most accurate non-invasive biomarkers of liver fat and fibrosis. We show that 14% of older adults with T2DM have advanced fibrosis and 6% have cirrhosis, which places them at risk for liver failure and liver cancer. Accurate prevalence rates and comparative analysis regarding the diagnostic accuracy of non-invasive tests in this population will guide the optimal screening strategy and future cost-effectiveness analyses. These results will inform future Hepatology and Endocrinology practice guidelines regarding NAFLD screening programs in older adults with T2DM.

Direct Comparison of Quantitative US versus Controlled Attenuation Parameter for Liver Fat Assessment Using MRI Proton Density Fat Fraction as the Reference Standard in Patients Suspected of Having NAFLD.

Background MRI-derived proton density fat fraction (PDFF) is an accurate, reliable, and safe biologic marker for use in the noninvasive diagnosis of hepatic steatosis in patients with nonalcoholic fatty liver disease (NAFLD). Because of the cost and limited availability of MRI, it is necessary to develop an accurate method to diagnose NAFLD with potential point-of-care access. Purpose To compare the diagnostic accuracy of the quantitative US (QUS) fat fraction (FF) estimator with that of the controlled attenuation parameter (CAP) in the diagnosis of NAFLD using contemporaneous MRI-derived PDFF as the reference standard. Materials and Methods Participants with or suspected of having NAFLD were prospectively recruited at the NAFLD Research Center between July 2015 and July 2019. All participants underwent MRI-derived PDFF measurement, transient elastography with CAP measurement, and QUS. QUS FF was derived using computed QUS parameters from the acquired radiofrequency US data using a calibrated reference phantom. The area under the receiver operating characteristic curve (AUC) was calculated to assess the accuracy of QUS FF and CAP in the diagnosis of hepatic steatosis (defined as MRI-derived PDFF ≥ 5%). AUCs were compared using the DeLong test. Results A total of 123 participants were included (mean age, 52 years ± 13 [SD]; 67 [54%] women). Of these participants, 100 (81%) had MRI-derived PDFF of 5% or more. QUS FF had a significantly higher AUC for diagnosis of NAFLD than did CAP (0.92 [95% CI: 0.87, 0.98] vs 0.79 [95% CI: 0.67, 0.90], P = .03). QUS FF had a sensitivity of 98% (98 of 100) and a specificity of 48% (11 of 23). CAP had a sensitivity of 87% (87 of 100) and a specificity of 57% (13 of 23). Conclusion The quantitative US fat fraction estimator is more accurate than the controlled attenuation parameter in the diagnosis of hepatic steatosis in patients with or suspected of having nonalcoholic fatty liver disease. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Ito in this issue.

MRE combined with FIB-4 (MEFIB) index in detection of candidates for pharmacological treatment of NASH-related fibrosis.

OBJECTIVE: Patients with non-alcoholic fatty liver disease (NAFLD) with ≥stage 2 fibrosis are at increased risk for liver-related mortality and are candidates for pharmacological therapies for treatment of NAFLD. The aim of this prospective cohort study is to examine the diagnostic accuracy of MR elastography (MRE) combined with fibrosis-4 (FIB-4) in diagnosing ≥stage 2 fibrosis (candidates for pharmacological therapies). DESIGN: This is a cross-sectional analysis of a prospective cohort (University of California at San Diego (UCSD)-NAFLD) including 238 consecutive patients with contemporaneous MRE and biopsy-proven NAFLD. Non-alcoholic steatohepatitis-Clinical Research Network-Histologic Scoring System was used to assess histology. The radiologist and pathologist were blinded to clinical, pathological and imaging data, respectively. Receiver operating characteristics (ROCs) were determined to examine the diagnostic accuracy of MRE and FIB-4 for diagnosis of ≥stage 2 fibrosis in NAFLD. We then validated these findings in an independent validation cohort derived from Yokohama City University in Japan (Japan-NAFLD Cohort; N=222 patients). RESULTS: In the UCSD-NAFLD (training) Cohort, MRE demonstrated a clinically significant diagnostic accuracy for the detection of ≥stage 2 fibrosis with an area under the ROC curve (AUROC) of 0.93 (95% CI 0.90 to 0.97) vs FIB-4 with an AUROC of 0.78 (95% CI 0.71 to 0.85), which was both clinically and statistically significant (p<0.0001). We then combined MRE with FIB-4 (MRE ≥3.3 kPa and FIB-4 ≥1.6) to develop a clinical prediction rule to rule in ≥stage 2 fibrosis patients which had positive predictive value (PPV) of 97.1% (p<0.02) in the UCSD-NAFLD cohort (AUROC of 0.90 (95% CI 0.85 to 0.95)) which remained significant at PPV of 91.0% (p<0.003) in the Japan-NAFLD Cohort (AUROC of 0.84 (95% CI 0.78 to 0.89)). CONCLUSION: MRE combined with FIB-4 (MEFIB) index may be used for non-invasive identification of candidates for (≥stage 2 fibrosis) pharmacological therapy among patients with NAFLD with a high PPV.

Clinical Utility of an Increase in Magnetic Resonance Elastography in Predicting Fibrosis Progression in Nonalcoholic Fatty Liver Disease.

BACKGROUND AND AIMS: Cross-sectional studies have shown that magnetic resonance elastography (MRE) is accurate in the noninvasive detection of advanced fibrosis in nonalcoholic fatty liver disease (NAFLD). However, there are limited data on the longitudinal association between an increase in liver stiffness on MRE and fibrosis progression in NAFLD. Therefore, using a well-characterized prospective cohort of patients with biopsy-proven NAFLD, we aimed to examine the longitudinal association between a 15% increase in liver stiffness on MRE and fibrosis progression in NAFLD. APPROACH AND RESULTS: This prospective cohort study included 102 patients (62.7% women) with biopsy-proven NAFLD who underwent contemporaneous MRE and liver biopsy at baseline followed by a repeat paired liver biopsy and MRE assessment. The primary outcome was odds of fibrosis progression by one or more stage as assessed by the Nonalcoholic Steatohepatitis Clinical Research Network histologic scoring system. The mean (±SD) of age and body mass index (BMI) were 52 (±14) years and 32.6 (±5.3) kg/m2 , respectively. The median time interval between the two paired assessments was 1.4 years (interquartile range 2.15 years). The number of patients with fibrosis stages 0, 1, 2, 3, and 4 was 27, 36, 12, 17, and 10, respectively. In unadjusted analysis, a 15% increase in MRE was associated with increased odds of histologic fibrosis progression (odds ratio [OR], 3.56; 95% confidence interval [CI], 1.17-10.76; P = 0.0248). These findings remained clinically and statistically significant even after multivariable adjustment for age, sex, and BMI (adjusted OR, 3.36; 95% CI, 1.10-10.31; P = 0.0339). A 15% increase in MRE was the strongest predictor of progression to advanced fibrosis (OR, 4.90; 95% CI, 1.35-17.84; P = 0.0159). CONCLUSIONS: A 15% increase in liver stiffness on MRE may be associated with histologic fibrosis progression and progression from early fibrosis to advanced fibrosis.

Liver Stiffness Severity is Associated With Increased Cardiovascular Risk in Patients With Type 2 Diabetes.

Cardiovascular disease (CVD) is the leading cause of death among patients with nonalcoholic fatty liver disease (NAFLD) and is strongly associated with type 2 diabetes mellitus (DM2).1 Accurately assessing CVD risk in NAFLD patients is critical to improving clinical outcomes.1 Use of liver stiffness measurements to noninvasively assess for liver fibrosis is broadening, and magnetic resonance elastography (MRE) is the most accurate modality in NAFLD.2 However, the association between fibrosis severity on MRE and the degree of CVD risk is unknown. The aim of this study was to determine whether MRE-assessed liver fibrosis stage is associated with CVD risk determined by Framingham risk score (FRS) and coronary artery calcium (CAC).

Prospective, Same-Day, Direct Comparison of Controlled Attenuation Parameter With the M vs the XL Probe in Patients With Nonalcoholic Fatty Liver Disease, Using Magnetic Resonance Imaging-Proton Density Fat Fraction as the Standard.

BACKGROUND & AIMS: Controlled attenuation parameter (CAP) measurements using M probe have been reported to be lower than those of the XL-probe in detection of hepatic steatosis. However, there has been no direct comparison of CAP with the M vs the XL probe in patients with nonalcoholic fatty liver disease (NAFLD). We compared CAP with the M vs the XL probe for quantification of hepatic fat content, using magnetic resonance imaging proton density fat fraction (MRI-PDFF) as the standard. METHODS: We performed a prospective study of 100 adults (mean body mass index [BMI], 30.6 ± 4.7 kg/m2) with and without NAFLD, assessed by CAP with the M probe and XL probe on the same day, at a single research center, from November 2017 through November 2018. We then measured the MRI-PDFF as the reference standard. Outcomes were presence of hepatic steatosis, defined as MRI-PDFF ≥ 5%, and detection of hepatic fat content ≥ 10%, defined as MRI-PDFF ≥ 10%. We performed area under the receiver operating characteristic curve (AUROC) analyses to assess the diagnostic accuracy of CAP for each probe in detection of hepatic steatosis (MRI-PDFF ≥ 5%) and of hepatic fat content ≥ 10%. RESULTS: Of the study participants, 68% had an MRI-PDFF of 5% or more and 48% had an MRI-PDFF of 10% or more. The mean CAP measured by the M probe (310 ± 62 db/m) was significantly lower than by the X probe (317 ± 63 db/m) (P = .007). When M probe was used in participants with BMIs <30 kg/m2 and XL probe in participants with BMIs ≥30 kg/m2, the CAP measured by the M probe (312 ± 51.4 db/m) remained significantly lower than that of the XL probe (345 ± 47.6 db/m) (P = .0035.), when the MRI-PDFF was above 5%. The optimal threshold of CAP for the detection of MRI-PDFF≥5%, was 294 db/m with the M probe and 307 db/m with the XL probe. The optimal threshold of CAP for the detection of MRI-PDFF ≥ 10%, was 311 db/m with the M probe and 322 db/m with the XL probe. For only the XL probe, CAP measurements with an interquartile range below 30 dB/m detected an MRI-PDFF≥5% with a lower AUROC (0.97; 95% CI, 0.80-1.00) than CAP measurements with an interquartile range above 30 dB/m (AUROC, 0.82; 95% CI, 0.71-0.90) (P = .0129). CONCLUSIONS: In an analysis of the same patients using CAP with the M probe and XL probe, with MRI-PDFF as the standard, we found that the M probe under-quantifies CAP values compared with the XL probe, independent of BMI. The type of probe should be considered when interpreting CAP data from patients with NAFLD.

Collagen Formation Assessed by N-Terminal Propeptide of Type 3 Procollagen Is a Heritable Trait and Is Associated With Liver Fibrosis Assessed by Magnetic Resonance Elastography.

N-terminal propeptide of type 3 procollagen (PRO-C3) is a biomarker of liver fibrosis in nonalcoholic fatty liver disease (NAFLD). This study examines the association between PRO-C3 concentration and liver fibrosis assessed by magnetic resonance elastography (MRE)-measured stiffness (MRE-stiffness) and the heritability of PRO-C3 concentration in a cohort of twins and families with and without NAFLD. We performed a cross-sectional analysis of a well-characterized prospective cohort of 306 participants, including 44 probands with NAFLD-cirrhosis and their 72 first-degree relatives, 24 probands with NAFLD without advanced fibrosis and their 24 first-degree relatives, and 72 controls without NAFLD and their 72 first-degree relatives. Liver steatosis was assessed by magnetic resonance imaging proton density fat fraction, and liver fibrosis was assessed by MRE-stiffness. Serum PRO-C3 was assessed by competitive, enzyme-linked immunosorbent assay. We assessed the familial correlation of PRO-C3 concentration, the shared gene effects between PRO-C3 concentration and liver steatosis and fibrosis, and the association between PRO-C3 concentration and genetic variants in the patatin-like phospholipase domain-containing 3 (PNPLA3), transmembrane 6 superfamily member 2 (TM6SF2), membrane-bound O-acyltransferase domain-containing (MBOAT), and glucokinase regulator (CGKR) genes. In multivariable-adjusted models including age, sex, body mass index, and ethnicity, serum PRO-C3 correlated strongly with liver fibrosis (r2  = 0.50, P < 0.001) and demonstrated robust heritability (h2 , 0.36; 95% confidence interval [CI], 0.07, 0.59; P = 0.016). PRO-C3 concentration and steatosis had a strong genetic correlation (shared genetic determination: 0.62; 95% CI, 0.236, 1.001; P = 0.002), whereas PRO-C3 concentration and fibrosis had a strong environmental correlation (shared environmental determination: 0.55; 95% CI, 0.317, 0.717; P < 0.001). PRO-C3 concentrations were higher in carriers of the TM6SF2 rs58542926-T allele compared with noncarriers: 15.7 (± 10.5) versus 10.8 (± 5.7) ng/L (P = 0.047). Conclusion: Serum PRO-C3 correlates with MRE-assessed fibrosis, is heritable, shares genetic correlation with liver steatosis and shares environmental correlation with liver fibrosis. PRO-C3 concentration appears to be linked to both fibrosis and steatosis and increased in carriers of the TM6SF2 rs58542926 risk allele.

Magnetic Resonance vs Transient Elastography Analysis of Patients With Nonalcoholic Fatty Liver Disease: A Systematic Review and Pooled Analysis of Individual Participants.

BACKGROUND & AIMS: Magnetic resonance elastography (MRE) and transient elastography (TE) are noninvasive techniques for detection of liver fibrosis. Single-center studies have compared the diagnostic performance of MRE vs TE in patients with nonalcoholic fatty liver disease (NAFLD). We conducted a pooled analysis of individual participant data from published studies to compare the diagnostic performance of MRE vs TE for staging of liver fibrosis in patients with NAFLD, using liver biopsy as reference. METHODS: We performed a systematic search of publication databases, from 2005 through 2017. We identified 3 studies of adults with NAFLD who were assessed by MRE, TE, and liver biopsy. In a pooled analysis, we calculated the cluster-adjusted area under the curve (AUROC) of MRE and TE for the detection of each stage of fibrosis. AUROC comparisons between MRE and TE were performed using the Delong test. RESULTS: Our pooled analysis included 230 participants with biopsy-proven NAFLD with mean age of 52.2±13.9 years and a body mass index of 31.9±7.5 kg/m2. The proportions of patients with fibrosis of stages 0, 1, 2, 3, and 4 were: 31.7%, 27.8%, 15.7%, 13.9%, and 10.9%, respectively. The AUROC of TE vs MRE for detection of fibrosis stages ≥1 was 0.82 (95% CI, 0.76-0.88) vs 0.87 (95% CI, 0.82-0.91) (P=.04); for stage≥ 2 was 0.87 (95% CI, 0.82-0.91) vs 0.92 (95% CI, 0.88-0.96) (P=.03); for stage ≥3 was 0.84 (95% CI, 0.78-0.90) vs 0.93 (95% CI, 0.89-0.96) (P=.001); for stage ≥ 4 was 0.84 (95% CI, 0.73-0.94) vs 0.94 (95% CI, 0.89-0.99) (P=.005). CONCLUSION: In a pooled analysis of data from individual participants with biopsy-proven NAFLD, we found MRE to have a statistically significantly higher diagnostic accuracy than TE in detection of each stage of fibrosis. MRE and TE each have roles in detection of fibrosis in patients with NAFLD, depending upon the level of accuracy desired.

Magnetic Resonance Imaging Proton Density Fat Fraction Associates With Progression of Fibrosis in Patients With Nonalcoholic Fatty Liver Disease.

Markers are needed to predict progression of nonalcoholic fatty liver disease (NAFLD). The proton density fat fraction, measured by magnetic resonance imaging (MRI-PDFF), provides an accurate, validated marker of hepatic steatosis; however, it is not clear whether the PDFF identifies patients at risk for NAFLD progression. We performed a follow-up study of 95 well-characterized patients with biopsy-proven NAFLD and examined the association between liver fat content and fibrosis progression. MRI-PDFF measurements were made at study entry (baseline). Biopsies were collected from patients at baseline and after a mean time period of 1.75 years. Among patients with no fibrosis at baseline, a higher proportion of patients in the higher liver fat group (MRI-PDFF ≥15.7%) had fibrosis progression (38.1%) than in the lower liver fat group (11.8%) (P = .067). In multivariable-adjusted logistic regression models (adjusted for age, sex, ethnicity, and body mass index), patients in the higher liver fat group had a significantly higher risk of fibrosis progression (multivariable-adjusted odds ratio 6.7; 95% confidence interval 1.01-44.1; P = .049). Our findings associate higher liver fat content, measured by MRI-PDFF, with fibrosis progression.

Link between gut-microbiome derived metabolite and shared gene-effects with hepatic steatosis and fibrosis in NAFLD.

Previous studies have shown that gut-microbiome is associated with nonalcoholic fatty liver disease (NAFLD). We aimed to examine if serum metabolites, especially those derived from the gut-microbiome, have a shared gene-effect with hepatic steatosis and fibrosis. This is a cross-sectional analysis of a prospective discovery cohort including 156 well-characterized twins and families with untargeted metabolome profiling assessment. Hepatic steatosis was assessed using magnetic-resonance-imaging proton-density-fat-fraction (MRI-PDFF) and fibrosis using MR-elastography (MRE). A twin additive genetics and unique environment effects (AE) model was used to estimate the shared gene-effect between metabolites and hepatic steatosis and fibrosis. The findings were validated in an independent prospective validation cohort of 156 participants with biopsy-proven NAFLD including shotgun metagenomics sequencing assessment in a subgroup of the cohort. In the discovery cohort, 56 metabolites including 6 microbial metabolites had a significant shared gene-effect with both hepatic steatosis and fibrosis after adjustment for age, sex and ethnicity. In the validation cohort, 6 metabolites were associated with advanced fibrosis. Among them, only one microbial metabolite, 3-(4-hydroxyphenyl)lactate, remained consistent and statistically significantly associated with liver fibrosis in the discovery and validation cohort (fold-change of higher-MRE versus lower-MRE: 1.78, P < 0.001 and of advanced versus no advanced fibrosis: 1.26, P = 0.037, respectively). The share genetic determination of 3-(4-hydroxyphenyl)lactate with hepatic steatosis was RG :0.57,95%CI:0.27-0.80, P < 0.001 and with fibrosis was RG :0.54,95%CI:0.036-1, P = 0.036. Pathway reconstruction linked 3-(4-hydroxyphenyl)lactate to several human gut-microbiome species. In the validation cohort, 3-(4-hydroxyphenyl)lactate was significantly correlated with the abundance of several gut-microbiome species, belonging only to Firmicutes, Bacteroidetes and Proteobacteria phyla, previously reported as associated with advanced fibrosis. Conclusion: This proof of concept study provides evidence of a link between the gut-microbiome and 3-(4-hydroxyphenyl)lactate that shares gene-effect with hepatic steatosis and fibrosis. (Hepatology 2018).

Optimal threshold of controlled attenuation parameter with MRI-PDFF as the gold standard for the detection of hepatic steatosis.

The optimal threshold of controlled attenuation parameter (CAP) for the detection of hepatic steatosis using both M and XL probe is unknown in nonalcoholic fatty liver disease (NAFLD). Magnetic resonance imaging proton density fat fraction (MRI-PDFF) is an accurate and precise method of detecting the presence of hepatic steatosis that is superior to CAP. Thus, the aim of this study was to evaluate the diagnostic accuracy and optimal threshold of CAP for the detection of hepatic steatosis as defined by MRI-PDFF ≥ 5%. This prospective cross-sectional study included 119 adults (59% women) with and without NAFLD who underwent MRI-PDFF and CAP using either M or XL probe when indicated within a 6-month period at the NAFLD Research Center, University of California, San Diego. The mean ( ± standard deviation) age and body mass index were 52.4 (±15.2) years and 29.9 (±5.5) kg/m2 , respectively. The prevalence of NAFLD (MRI-PDFF ≥ 5%) and MRI-PDFF ≥ 10% was 70.6% and 47.1%, respectively. The area under the receiver operating characteristic (AUROC) of CAP for the detection of MRI-PDFF ≥ 5% was 0.80 (95% confidence interval [CI], 0.70-0.90) at the cut-point of 288 dB/m and of MRI-PDFF ≥ 10% was 0.87 (95% CI, 0.80-0.94) at the cut-point of 306 dB/m. When stratified by the interquartile range (IQR) of CAP, we observed that an IQR below the median (30 dB/m) had a robust AUROC compared with an IQR above the median (0.92 [95% CI, 0.85-1.00] versus 0.70 [95% CI, 0.56-0.85]; P = 0.0117), and these differences were statistically and clinically significant. CONCLUSION: The cut-point of CAP for presence of hepatic steatosis (MRI-PDFF ≥ 5%) was 288 dB/m. The diagnostic accuracy of CAP for the detection of hepatic steatosis is more reliable when the IQR of CAP is <30 dB/m. These data have implications for the clinical use of CAP in the assessment of NAFLD. (Hepatology 2018;67:1348-1359).

Association Between Obesity and Discordance in Fibrosis Stage Determination by Magnetic Resonance vs Transient Elastography in Patients With Nonalcoholic Liver Disease.

BACKGROUND & AIMS: Magnetic resonance elastography (MRE) and transient elastography (TE) are noninvasive techniques used to detect liver fibrosis in nonalcoholic fatty liver disease. MRE detects fibrosis more accurately than TE, but MRE is more expensive, and the concordance between MRE and TE have not been optimally assessed in obese patients. It is important to determine under which conditions TE and MRE produce the same readings, so that some patients can simply undergo TE evaluation to detect fibrosis. We aimed to assess the association between body mass index (BMI) and discordancy between MRE and TE findings, using liver biopsy as the reference, and validated our findings in a separate cohort. METHODS: We performed a cross-sectional study of 119 adults with nonalcoholic fatty liver disease who underwent MRE, TE with M and XL probe, and liver biopsy analysis from October 2011 through January 2017 (training cohort). MRE and TE results were considered to be concordant if they found patients to have the same stage fibrosis as liver biopsy analysis. We validated our findings in 75 adults with nonalcoholic fatty liver disease who underwent contemporaneous MRE, TE, and liver biopsy at a separate institution from March 2010 through May 2013. The primary outcome was rate of discordance between MRE and TE in determining stage of fibrosis (stage 2-4 vs 0-1). Secondary outcomes were the rate of discordance between MRE and TE in determining dichotomized stage of fibrosis (1-4 vs 0, 3-4 vs 0-2, and 4 vs 0-3). RESULTS: In the training cohort, there was 43.7% discordance in findings from MRE versus TE. BMI associated significantly with discordance in findings from MRE versus TE (odds ratio, 1.69; 95% confidence interval, 1.15-2.51; P = .008) after multivariable adjustment by age and sex. The findings were confirmed in the validation cohort: there was 45.3% discordance in findings from MRE versus TE. BMI again associated significantly with discordance in findings from MRE versus TE (odds ratio, 1.52; 95% confidence interval, 1.04-2.21; P = .029) after multivariable adjustment by age and sex. CONCLUSIONS: We identified and validated BMI as a factor significantly associated with discordance of findings from MRE versus TE in assessment of fibrosis stage. The degree of discordancy increases with BMI.

Magnetic Resonance Elastography vs Transient Elastography in Detection of Fibrosis and Noninvasive Measurement of Steatosis in Patients With Biopsy-Proven Nonalcoholic Fatty Liver Disease.

BACKGROUND & AIMS: Magnetic resonance imaging (MRI) techniques and ultrasound-based transient elastography (TE) can be used in noninvasive diagnosis of fibrosis and steatosis in patients with nonalcoholic fatty liver disease (NAFLD). We performed a prospective study to compare the performance of magnetic resonance elastography (MRE) vs TE for diagnosis of fibrosis, and MRI-based proton density fat fraction (MRI-PDFF) analysis vs TE-based controlled attenuation parameter (CAP) for diagnosis of steatosis in patients undergoing biopsy to assess NAFLD. METHODS: We performed a cross-sectional study of 104 consecutive adults (56.7% female) who underwent MRE, TE, and liver biopsy analysis (using the histologic scoring system for NAFLD from the Nonalcoholic Steatohepatitis Clinical Research Network Scoring System) from October 2011 through May 2016 at a tertiary medical center. All patients received a standard clinical evaluation, including collection of history, anthropometric examination, and biochemical tests. The primary outcomes were fibrosis and steatosis. Secondary outcomes included dichotomized stages of fibrosis and nonalcoholic steatohepatitis vs no nonalcoholic steatohepatitis. Receiver operating characteristic curve analyses were used to compare performances of MRE vs TE in diagnosis of fibrosis (stages 1-4 vs 0) and MRI-PDFF vs CAP for diagnosis of steatosis (grades 1-3 vs 0) with respect to findings from biopsy analysis. RESULTS: MRE detected any fibrosis (stage 1 or more) with an area under the receiver operating characteristic curve (AUROC) of 0.82 (95% confidence interval [CI], 0.74-0.91), which was significantly higher than that of TE (AUROC, 0.67; 95% CI, 0.56-0.78). MRI-PDFF detected any steatosis with an AUROC of 0.99 (95% CI, 0.98-1.00), which was significantly higher than that of CAP (AUROC, 0.85; 95% CI, 0.75-0.96). MRE detected fibrosis of stages 2, 3, or 4 with AUROC values of 0.89 (95% CI, 0.83-0.96), 0.87 (95% CI, 0.78-0.96), and 0.87 (95% CI, 0.71-1.00); TE detected fibrosis of stages 2, 3, or 4 with AUROC values of 0.86 (95% CI, 0.77-0.95), 0.80 (95% CI, 0.67-0.93), and 0.69 (95% CI, 0.45-0.94). MRI-PDFF identified steatosis of grades 2 or 3 with AUROC values of 0.90 (95% CI, 0.82-0.97) and 0.92 (95% CI, 0.84-0.99); CAP identified steatosis of grades 2 or 3 with AUROC values of 0.70 (95% CI, 0.58-0.82) and 0.73 (95% CI, 0.58-0.89). CONCLUSIONS: In a prospective, cross-sectional study of more than 100 patients, we found MRE to be more accurate than TE in identification of liver fibrosis (stage 1 or more), using biopsy analysis as the standard. MRI-PDFF is more accurate than CAP in detecting all grades of steatosis in patients with NAFLD.

Increased severity of liver fat content and liver fibrosis in non-alcoholic fatty liver disease correlate with epicardial fat volume in type 2 diabetes: A prospective study.

OBJECTIVES: To determine whether severity of non-alcoholic fatty liver disease (NAFLD) and liver fibrosis quantitatively assessed in individuals with diabetes mellitus (DM)-2 correlate with increased coronary heart disease (CHD) risk using non-invasive markers. METHODS: We conducted a single-centre, prospective, cross-sectional study in 100 consecutive diabetic individuals without known CHD recruited between March 2013 and September 2014. History, physical examination, serum markers, cardiac computed tomography (CT), magnetic resonance (MR) imaging-estimated proton density fat fraction (PDFF) and MR elastography (MRE) were obtained for 95 participants. Written informed consent was provided. Institutional review board approved this study. Spearman rank correlation was performed to assess for correlations. Multiple linear regression model determined independent predictors of epicardial adipose tissue (EAT) volume. RESULTS: A p value < 0.05 determined statistical significance. The EAT volume was higher in the NAFLD group, defined as MR-imaging PDFF ≥ 5 %, compared to the non-NAFLD group (126.5 ml (IQR 80.9) versus 85.4 ml (IQR 44.7), p=0.002). MR imaging-PDFF correlated with EAT (r=0.42, p < 0.0001). MR imaging-PDFF and liver fibrosis were independently associated with EAT. CONCLUSIONS: Higher liver fat content and liver fibrosis may portend worse cardiovascular risk in diabetics. KEY POINTS: • EAT volume is higher in diabetic individuals with NAFLD. • Liver fat content is positively correlated with EAT. • Liver fat content and liver fibrosis were independently associated with EAT. • Higher liver fat content and fibrosis may adversely affect cardiovascular risk.

Shared genetic effects between hepatic steatosis and fibrosis: A prospective twin study.

Nonalcoholic fatty liver disease is associated with metabolic risk factors including hypertension and dyslipidemia and may progress to liver fibrosis. Studies have shown that hepatic steatosis and fibrosis are heritable, but whether they have a significant shared gene effect is unknown. This study examined the shared gene effects between hepatic steatosis and fibrosis and their associations with metabolic risk factors. This was a cross-sectional analysis of a prospective cohort of well-characterized, community-dwelling twins (45 monozygotic, 20 dizygotic twin pairs, 130 total subjects) from southern California. Hepatic steatosis was assessed with magnetic resonance imaging-proton density fat fraction and hepatic fibrosis with magnetic resonance elastography. A standard bivariate twin additive genetics and unique environment effects model was used to estimate the proportion of phenotypic variance between two phenotypes accounted for by additive genetic effects and individual-specific environmental effects. Genetic correlations estimated from this model represent the degree to which the genetic determinants of two phenotypes overlap. Mean (± standard deviation) age and body mass index were 47.1 (±21.9) years and 26.2 (±5.8) kg/m2 , respectively. Among the cohort, 20% (26/130) had hepatic steatosis (magnetic resonance imaging-proton density fat fraction ≥5%), and 8.2% (10/122) had hepatic fibrosis (magnetic resonance elastography ≥3 kPa). Blood pressure (systolic and diastolic), triglycerides, glucose, homeostatic model assessment of insulin resistance, insulin, hemoglobin A1c, and low high-density lipoprotein had significant shared gene effects with hepatic steatosis. Triglycerides, glucose, homeostatic model assessment of insulin resistance, insulin, hemoglobin A1c, and low high-density lipoprotein had significant shared gene effects with hepatic fibrosis. Hepatic steatosis and fibrosis had a highly significant shared gene effect of 0.756 (95% confidence interval 0.716-1, P < 0.0001). CONCLUSIONS: Genes involved with steatosis pathogenesis may also be involved with fibrosis pathogenesis. (Hepatology 2016;64:1547-1558).

Sitagliptin vs. placebo for non-alcoholic fatty liver disease: A randomized controlled trial.

BACKGROUND & AIMS: Uncontrolled studies show sitagliptin, an oral DPP-4 inhibitor, may improve alanine aminotransferase and liver histology in non-alcoholic fatty liver disease (NAFLD) patients. We aimed to compare sitagliptin vs. the efficacy of a placebo in reducing liver fat measured by MRI-derived proton density-fat fraction (MRI-PDFF). METHODS: This randomized, double-blind, allocation-concealed, placebo-controlled trial included 50 NAFLD patients with prediabetes or early diabetes randomized to sitagliptin orally 100mg/day or placebo for 24weeks. Primary outcome was liver fat change measured by MRI-PDFF in colocalized regions of interest within each of nine liver segments. Additional advanced assessments included MR spectroscopy (MRS) for internal validation of MRI-PDFF's accuracy, and magnetic resonance elastography (MRE) and FIBROSpect® II to assess liver fibrosis. RESULTS: Sitagliptin was not significantly better than placebo in reducing liver fat measured by MRI-PDFF (mean difference between sitagliptin and placebo arms: -1.3%, p=0.4). Compared to baseline, there were no significant differences in end-of-treatment MRI-PDFF for sitagliptin (18.1% to 16.9%, p=0.27) or placebo (16.6% to 14.0%, p=0.07). The groups had no significant differences for changes in alanine aminotransferase, aspartate aminotransferase, low-density lipoprotein, homeostatic model assessment insulin resistance, and MRE-derived liver stiffness. In both groups at baseline and post-treatment, MRI-PDFF and MRS showed robust correlation coefficients ranging from r(2)=0.96 to r(2)=0.99 (p<0.0001), demonstrating the strong internal validity of the findings. FIBROSpect® II showed no changes in the sitagliptin group but was significantly increased in the placebo group (p=0.03). CONCLUSIONS: Sitagliptin was safe but not better than placebo in reducing liver fat in prediabetic or diabetic patients with NAFLD. LAY SUMMARY: In a randomized, double-blind, placebo-controlled study, the anti-diabetic drug sitagliptin was no more effective than placebo for improving liver fat and liver fibrosis in patients with non-alcoholic fatty liver disease. This study demonstrates that non-invasive magnetic resonance imaging techniques, including magnetic resonance imaging-proton density-fat fraction and magnetic resonance elastography, can be used to assess treatment response in non-alcoholic fatty liver disease clinical trials.

Association of Nonalcoholic Fatty Liver Disease With Visceral Adiposity but Not Coronary Artery Calcification in the Elderly.

BACKGROUND & AIMS: Nonalcoholic fatty liver disease (NAFLD) is related closely to risk factors for coronary artery disease, but it is unclear whether NAFLD independently contributes to atherosclerosis. We investigated the association between NAFLD and coronary artery calcium (CAC) scores, determined based on noncontrast cardiac computed tomography data, in an elderly cohort. METHODS: We conducted a longitudinal, cross-sectional study of data from 250 participants (mean age, 67.6 ± 7.0 y; 43.2% men) in the Rancho Bernardo Study-a prospective population-based study of mostly white adults in suburban Southern California. We compared CAC scores, liver-to-spleen attenuation ratio, and volumes of visceral adipose tissue (VAT) at baseline and after a 5-year follow-up period. RESULTS: We assigned participants to groups based on CAC scores (0, 0-10, 11-100, 101-400, and >400). Among groups, the liver-to-spleen attenuation ratio did not vary significantly, but VAT increased with CAC score (median and interquartile range values were as follows: 50.0 [33.3-77.4] cm(3), 63.0 [33.9-93.1] cm(3), 66.1 [48.2-80.2] cm(3), 69.1 [48.1-85.0] cm(3), 76.1 [53.1-108.5] cm(3) for CAC groups; P = .0054). In multivariable regression analysis, NAFLD at baseline was not associated with an increased risk of a CAC score greater than 0. Longitudinal analysis showed that visceral fat, but not hepatic steatosis, increased in participants with increasing CAC scores (interquartile range 57.1-92.4) vs 55.2 cm(3) in patients without (interquartile range 36.5-81.1, P = .0401). The proportion of patients with NAFLD decreased after the 5-year follow-up period (from 29.3% before to 14.1% afterward; P = .0081), despite increased mean CAC scores and VAT volume in patients. CONCLUSIONS: In adults age 67.6 ± 7.0 years, the proportion with NAFLD decreased despite increasing CAC score and VAT with age. There was no clear association between NAFLD and CAC score. However, VAT was associated with baseline and increasing CAC scores. Visceral adiposity therefore might be a risk factor for coronary artery disease.

Heritability of Hepatic Fibrosis and Steatosis Based on a Prospective Twin Study.

BACKGROUND & AIMS: Little is known about the heritability of hepatic fibrosis, and the heritability of hepatic steatosis has not been assessed systematically in adults. We investigated the heritability of hepatic fibrosis and steatosis in a community-dwelling twin cohort. METHODS: We performed a cross-sectional analysis of a cohort of well-characterized twins residing in Southern California including 60 pairs of twins (42 monozygotic and 18 dizygotic; average age, 45.7 ± 22.1 y; average body mass index, 26.4 ± 5.7 kg/m(2)). We collected data on medical history, physical examinations, fasting laboratory test results, and liver health; all participants underwent an advanced magnetic resonance imaging (MRI) examination of the liver from January 2012 through January 2015. Hepatic steatosis was quantified noninvasively by MRI and determined based on the proton-density fat fraction (MRI-PDFF); liver fibrosis was measured based on stiffness measured by magnetic resonance elastography. RESULTS: Twenty-six of the 120 subjects (21.7%) had nonalcoholic fatty liver disease (defined as MRI-PDFF ≥ 5% after exclusion of other causes of hepatic steatosis). The presence of hepatic steatosis correlated between monozygotic twins (r(2) = 0.70; P < .0001) but not between dizygotic twins (r(2) = 0.36; P = .2). The level of liver fibrosis also correlated between monozygotic twins (r(2) = 0.48; P < .002) but not between dizygotic twins (r(2) = 0.12; P = .7). In multivariable models adjusted for age, sex, and ethnicity, the heritability of hepatic steatosis (based on MRI-PDFF) was 0.52 (95% confidence interval, 0.31-0.73; P < 1.1 × 10(-11)) and the heritability of hepatic fibrosis (based on liver stiffness) was 0.5 (95% confidence interval, 0.28-0.72; P <6.1 × 10(-11)). CONCLUSIONS: A study of twins provides evidence that hepatic steatosis and hepatic fibrosis are heritable traits.