Allen, Alina M.

Background and Aims: Magnetic resonance elastography (MRE) is an accurate, continuous biomarker of liver fibrosis; however, the optimal combination with clinical factors to predict the risk of incident hepatic decompensation is unknown. Therefore, we aimed to develop and validate an MRE-based prediction model for hepatic decompensation for patients with NAFLD. Approach and Results: This international multicenter cohort study included participants with NAFLD undergoing MRE from 6 hospitals. A total of 1254 participants were randomly assigned as training (n = 627) and validation (n = 627) cohorts. The primary end point was hepatic decompensation, defined as the first occurrence of variceal hemorrhage, ascites, or HE. Covariates associated with hepatic decompensation on Cox-regression were combined with MRE to construct a risk prediction model in the training cohort and then tested in the validation cohort. The median (IQR) age and MRE values were 61 (18) years and 3.5 (2.5) kPa in the training cohort and 60 (20) years and 3.4 (2.5) kPa in the validation cohort, respectively. The MRE-based multivariable model that included age, MRE, albumin, aspartate aminotransferase, and platelets had excellent discrimination for the 3- and 5-year risk of hepatic decompensation (c-statistic 0.912 and 0.891, respectively) in the training cohort. The diagnostic accuracy remained consistent in the validation cohort with a c-statistic of 0.871 and 0.876 for hepatic decompensation at 3 and 5 years, respectively, and was superior to Fibrosis-4 in both cohorts (p < 0.05). Conclusions: An MRE-based prediction model allows for accurate prediction of hepatic decompensation and assists in the risk stratification of patients with NAFLD.

ABSTRACT Although physical activity (PA) is crucial in the prevention and clinical management of nonalcoholic fatty liver disease, most individuals with this chronic disease are inactive and do not achieve recommended amounts of PA. There is a robust and consistent body of evidence highlighting the benefit of participating in regular PA, including a reduction in liver fat and improvement in body composition, cardiorespiratory fitness, vascular biology, and health-related quality of life. Importantly, the benefits of regular PA can be seen without clinically significant weight loss. At least 150 min of moderate or 75 min of vigorous intensity PA are recommended weekly for all patients with nonalcoholic fatty liver disease, including those with compensated cirrhosis. If a formal exercise training program is prescribed, aerobic exercise with the addition of resistance training is preferred. In this roundtable document, the benefits of PA are discussed, along with recommendations for 1) PA assessment and screening; 2) how best to advise, counsel, and prescribe regular PA; and 3) when to refer to an exercise specialist.

Background and Aims: The presence of at-risk NASH is associated with an increased risk of cirrhosis and complications. Therefore, noninvasive identification of at-risk NASH with an accurate biomarker is a critical need for pharmacologic therapy. We aim to explore the performance of several magnetic resonance (MR)-based imaging parameters in diagnosing at-risk NASH. Approach and Results: This prospective clinical trial (NCT02565446) includes 104 paired MR examinations and liver biopsies performed in patients with suspected or diagnosed NAFLD. Magnetic resonance elastography-assessed liver stiffness (LS), 6-point Dixon-derived proton density fat fraction (PDFF), and single-point saturation-recovery acquisition-calculated T1 relaxation time were explored. Among all predictors, LS showed the significantly highest accuracy in diagnosing at-risk NASH [AUCLS: 0.89 (0.82, 0.95), AUCPDFF: 0.70 (0.58, 0.81), AUCT1: 0.72 (0.61, 0.82), z-score test z >1.96 for LS vs any of others]. The optimal cutoff value of LS to identify at-risk NASH patients was 3.3 kPa (sensitivity: 79%, specificity: 82%, negative predictive value: 91%), whereas the optimal cutoff value of T1 was 850 ms (sensitivity: 75%, specificity: 63%, and negative predictive value: 87%). PDFF had the highest performance in diagnosing NASH with any fibrosis stage [AUCPDFF: 0.82 (0.72, 0.91), AUCLS: 0.73 (0.63, 0.84), AUCT1: 0.72 (0.61, 0.83), |z| <1.96 for all]. Conclusion: Magnetic resonance elastography-assessed LS alone outperformed PDFF, and T1 in identifying patients with at-risk NASH for therapeutic trials.

Background and Aims: We present findings from the inaugural American College of Sports Medicine (ACSM) International Multidisciplinary Roundtable, which was convened to evaluate the evidence for physical activity as a means of preventing or modifying the course of NAFLD. Approach and Results: A scoping review was conducted to map the scientific literature and identify key concepts, research gaps, and evidence available to inform clinical practice, policymaking, and research. The scientific evidence demonstrated regular physical activity is associated with decreased risk of NAFLD development. Low physical activity is associated with a greater risk for disease progression and extrahepatic cancer. During routine health care visits, all patients with NAFLD should be screened for and counseled about physical activity benefits, including reduction in liver fat and improvement in body composition, fitness, and quality of life. While most physical activity benefits occur without clinically significant weight loss, evidence remains limited regarding the association between physical activity and liver fibrosis. At least 150 min/wk of moderate or 75 min/wk of vigorous-intensity physical activity are recommended for all patients with NAFLD. If a formal exercise training program is prescribed, aerobic exercise with the addition of resistance training is preferred. Conclusions: The panel found consistent and compelling evidence that regular physical activity plays an important role in preventing NAFLD and improving intermediate clinical outcomes. Health care, fitness, and public health professionals are strongly encouraged to disseminate the information in this report. Future research should prioritize determining optimal strategies for promoting physical activity among individuals at risk and in those already diagnosed with NAFLD.

Background and aims: The American Gastroenterological Association (AGA) recently launched the Clinical Care Pathway for the Risk Stratification and Management of Patients with NAFLD to identify adults with significant fibrosis. We aimed to examine this pathway’s performance in the US population. Approach and Results: Using the 2017–2018 National Health and Nutrition Examination Survey data, we identified participants aged ≥18 with available Fibrosis‐4 (FIB‐4) score and liver stiffness measurement (LSM) in the absence of other liver diseases. Based on the AGA clinical pathway, FIB‐4 < 1.3 and LSM < 8 kilopascals (kPa) by vibration‐controlled transient elastography (VCTE) are associated with low risk of significant fibrosis. Using these cutoffs, we examined the pathway performance using negative predictive value (NPV) and positive predictive value (PPV) and explored alternative risk‐stratification strategies. There were 2322 participants with available data (projected to 94.2 million US adults). The NPV of LSM ≥ 8 kPa among those with FIB‐4 < 1.3 was 90%, whereas the PPV among those with FIB‐4 1.3–2.67 was 13%. As diabetes was a strong predictor of fibrosis, we propose a simple, alternative strategy to eliminate the indeterminate FIB‐4 range and perform VCTE in those with FIB‐4 ≥ 1.3 and diabetes. This strategy would decrease the number of VCTEs from 14.5 to 4.9 million and increase PPV from 13% to 33% without compromising the NPV among those who did not undergo VCTE. Conclusion: The implementation of the current AGA clinical pathway would lead to overutilization of VCTE. An alternative strategy using FIB‐4 ≥ 1.3 and diabetes to select adults undergoing second‐line testing will improve this pathway’s performance and minimize unnecessary VCTEs.

Background and Aims: The impact of disease progression in NAFLD on liver outcomes remains poorly understood. We aimed to investigate NAFLD progression using longitudinal liver stiffness measurements (LSM) by serial magnetic resonance elastography (MRE) and the association with liver outcomes. Approach and Results: All adult patients with NAFLD who underwent at least two serial MREs for clinical evaluation at Mayo Clinic, Rochester, between 2007 and 2019 were identified from the institutional database. Progression and regression were defined based on LSM change of 19% above or below 19% of initial LSM, respectively, based on Quantitative Imaging Biomarker Alliance consensus. The association between change in LSM and liver‐related outcomes occurring after the last MRE was examined using time‐to‐event analysis. A total of 128 participants underwent serial MREs (53% female, median age 59 years). The median time between paired MREs was 3.4 (range 1–10.7) years. NAFLD progression (LSM = +0.61 kPa/year) was identified in 17 patients (13.3%). NAFLD regression (−0.40 kPa/year) occurred in 35 patients (27.3%). Stable LSM was noted in 76 participants (59.4%). In NAFLD without cirrhosis at baseline ( n = 75), cirrhosis development occurred in 14% of LSM progressors and 2.9% of non‐progressors ( p = 0.059) over a median 2.7 years of follow‐up from the last MRE. Among those with compensated cirrhosis at baseline MRE ( n = 29), decompensation or death occurred in 100% of LSM progressors and 19% of non‐progressors ( p < 0.001) over a median 2.5 years of follow‐up after the last MRE. Conclusions: Noninvasive monitoring of LSM by conventional MRE is a promising method of longitudinal NAFLD monitoring and risk estimation of liver‐related outcomes in NAFLD.