Comparison of plasma biomarkers and amyloid PET for predicting memory decline in cognitively unimpaired individuals.

BACKGROUND: We compared the ability of several plasma biomarkers versus amyloid positron emission tomography (PET) to predict rates of memory decline among cognitively unimpaired individuals. METHODS: We studied 645 Mayo Clinic Study of Aging participants. Predictor variables were age, sex, education, apolipoprotein E (APOE) ε4 genotype, amyloid PET, and plasma amyloid beta (Aß)42/40, phosphorylated tau (p-tau)181, neurofilament light (NfL), glial fibrillary acidic protein (GFAP), and p-tau217. The outcome was a change in a memory composite measure. RESULTS: All plasma biomarkers, except NfL, were associated with mean memory decline in models with individual biomarkers. However, amyloid PET and plasma p-tau217, along with age, were key variables independently associated with mean memory decline in models combining all predictors. Confidence intervals were narrow for estimates of population mean prediction, but person-level prediction intervals were wide. DISCUSSION: Plasma p-tau217 and amyloid PET provide useful information about predicting rates of future cognitive decline in cognitively unimpaired individuals at the population mean level, but not at the individual person level.

Modeling the temporal evolution of plasma p-tau in relation to amyloid beta and tau PET.

INTRODUCTION: The timing of plasma biomarker changes is not well understood. The goal of this study was to evaluate the temporal co-evolution of plasma and positron emission tomography (PET) Alzheimer's disease (AD) biomarkers. METHODS: We included 1408 Mayo Clinic Study of Aging and Alzheimer's Disease Research Center participants. An accelerated failure time (AFT) model was fit with amyloid beta (Aß) PET, tau PET, plasma p-tau217, p-tau181, and glial fibrillary acidic protein (GFAP) as endpoints. RESULTS: Individual timing of plasma p-tau progression was strongly associated with Aß PET and GFAP progression. In the population, GFAP became abnormal first, then Aß PET, plasma p-tau, and tau PET temporal meta-regions of interest when applying cut points based on young, cognitively unimpaired participants. DISCUSSION: Plasma p-tau is a stronger indicator of a temporally linked response to elevated brain Aß than of tau pathology. While Aß deposition and a rise in GFAP are upstream events associated with tau phosphorylation, the temporal link between p-tau and Aß PET was the strongest. HIGHLIGHTS: Plasma p-tau progression was more strongly associated with Aß than tau PET. Progression on plasma p-tau was associated with Aß PET and GFAP progression. P-tau181 and p-tau217 become abnormal after Aß PET and before tau PET. GFAP became abnormal first, before plasma p-tau and Aß PET.

Evidence against a temporal association between cerebrovascular disease and Alzheimer's disease imaging biomarkers.

Whether a relationship exists between cerebrovascular disease and Alzheimer's disease has been a source of controversy. Evaluation of the temporal progression of imaging biomarkers of these disease processes may inform mechanistic associations. We investigate the relationship of disease trajectories of cerebrovascular disease (white matter hyperintensity, WMH, and fractional anisotropy, FA) and Alzheimer's disease (amyloid and tau PET) biomarkers in 2406 Mayo Clinic Study of Aging and Mayo Alzheimer's Disease Research Center participants using accelerated failure time models. The model assumes a common pattern of progression for each biomarker that is shifted earlier or later in time for each individual and represented by a per participant age adjustment. An individual's amyloid and tau PET adjustments show very weak temporal association with WMH and FA adjustments (R = -0.07 to 0.07); early/late amyloid or tau timing explains <1% of the variation in WMH and FA adjustment. Earlier onset of amyloid is associated with earlier onset of tau (R = 0.57, R2 = 32%). These findings support a strong mechanistic relationship between amyloid and tau aggregation, but not between WMH or FA and amyloid or tau PET.

Head-to-head comparison of magnetic resonance elastography-based liver stiffness, fat fraction, and T1 relaxation time in identifying at-risk NASH.

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 [AUC LS : 0.89 (0.82, 0.95), AUC PDFF : 0.70 (0.58, 0.81), AUC T1 : 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 [AUC PDFF : 0.82 (0.72, 0.91), AUC LS : 0.73 (0.63, 0.84), AUC T1 : 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.

CS-iCCA, A New Clinically Based Staging System for Intrahepatic Cholangiocarcinoma: Establishment and External Validation.

INTRODUCTION: Intrahepatic cholangiocarcinoma (iCCA) is a primary liver malignancy with poor prognosis. Current prognostic methods are most accurate for patients with surgically resectable disease. However, a significant proportion of patients with iCCA are not surgical candidates. We aimed to develop a generalizable staging system based on clinical variables to determine prognosis of all patients with iCCA. METHODS: The derivation cohort included 436 patients with iCCA seen between 2000 and 2011. For external validation, 249 patients with iCCA seen from 2000 to 2014 were enrolled. Survival analysis was performed to identify prognostic predictors. All-cause mortality was the primary end point. RESULTS: Eastern Cooperative Oncology Group status, tumor number, tumor size, metastasis, albumin, and carbohydrate antigen 19-9 were incorporated into a 4-stage algorithm. Kaplan-Meier estimates for 1-year survival were 87.1% (95% confidence interval [CI] 76.1-99.7), 72.7% (95% CI 63.4-83.4), 48.0% (95% CI 41.2-56.0), and 16% (95% CI 11-23.5), respectively, for stages I, II, III, and IV. Univariate analysis yielded significant differences in risk of death for stages II (hazard ratio [HR] 1.71; 95% CI 1.0-2.8), III (HR 3.32; 95% CI 2.07-5.31), and IV (HR 7.44; 95% CI 4.61-12.01) compared with stage I (reference). Concordance indices showed the new staging system was superior to the TNM staging for predicting mortality in the derivation cohort, P < 0.0001. In the validation cohort, however, the difference between the 2 staging systems was not significant. DISCUSSION: The proposed independently validated staging system uses nonhistopathologic data to successfully stratify patients into 4 stages. This staging system has better prognostic accuracy compared with the TNM staging and can assist physicians and patients in treatment of iCCA.

Predicting amyloid PET and tau PET stages with plasma biomarkers.

Staging the severity of Alzheimer's disease pathology using biomarkers is useful for therapeutic trials and clinical prognosis. Disease staging with amyloid and tau PET has face validity; however, this would be more practical with plasma biomarkers. Our objectives were, first, to examine approaches for staging amyloid and tau PET and, second, to examine prediction of amyloid and tau PET stages using plasma biomarkers. Participants (n = 1136) were enrolled in either the Mayo Clinic Study of Aging or the Alzheimer's Disease Research Center; had a concurrent amyloid PET, tau PET and blood draw; and met clinical criteria for cognitively unimpaired (n = 864), mild cognitive impairment (n = 148) or Alzheimer's clinical syndrome with dementia (n = 124). The latter two groups were combined into a cognitively impaired group (n = 272). We used multinomial regression models to estimate discrimination [concordance (C) statistics] among three amyloid PET stages (low, intermediate, high), four tau PET stages (Braak 0, 1-2, 3-4, 5-6) and a combined amyloid and tau PET stage (none/low versus intermediate/high severity) using plasma biomarkers as predictors separately within unimpaired and impaired individuals. Plasma analytes, p-tau181, Aß1-42 and Aß1-40 (analysed as the Aß42/Aß40 ratio), glial fibrillary acidic protein and neurofilament light chain were measured on the HD-X Simoa Quanterix platform. Plasma p-tau217 was also measured in a subset (n = 355) of cognitively unimpaired participants using the Lilly Meso Scale Discovery assay. Models with all Quanterix plasma analytes along with risk factors (age, sex and APOE) most often provided the best discrimination among amyloid PET stages (C = 0.78-0.82). Models with p-tau181 provided similar discrimination of tau PET stages to models with all four plasma analytes (C = 0.72-0.85 versus C = 0.73-0.86). Discriminating a PET proxy of intermediate/high from none/low Alzheimer's disease neuropathological change with all four Quanterix plasma analytes was excellent but not better than p-tau181 only (C = 0.88 versus 0.87 for unimpaired and C = 0.91 versus 0.90 for impaired). Lilly p-tau217 outperformed the Quanterix p-tau181 assay for discriminating high versus intermediate amyloid (C = 0.85 versus 0.74) but did not improve over a model with all Quanterix plasma analytes and risk factors (C = 0.85 versus 0.83). Plasma analytes along with risk factors can discriminate between amyloid and tau PET stages and between a PET surrogate for intermediate/high versus none/low neuropathological change with accuracy in the acceptable to excellent range. Combinations of plasma analytes are better than single analytes for many staging predictions with the exception that Quanterix p-tau181 alone usually performed equivalently to combinations of Quanterix analytes for tau PET discrimination.

Change in serial liver stiffness measurement by magnetic resonance elastography and outcomes in NAFLD.

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.

Performance of American Gastroenterological Association Clinical Care Pathway for the risk stratification of patients with nonalcoholic fatty liver disease in the US population.

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.

The Utility of Multistate Models: A Flexible Framework for Time-to-Event Data.

Purpose of Review: Survival analyses are common and essential in medical research. Most readers are familiar with Kaplan-Meier curves and Cox models; however, very few are familiar with multistate models. Although multistate models were introduced in 1965, they only recently receive more attention in the medical research community. The current review introduces common terminologies and quantities that can be estimated from multistate models. Examples from published literature are used to illustrate the utility of multistate models. Recent Findings: A figure of states and transitions is a useful depiction of a multistate model. Clinically meaningful quantities that can be estimated from a multistate model include the probability in a state at a given time, the average time in a state, and the expected number of visits to a state; all of which describe the absolute risks of an event. Relative risk can also be estimated using multistate hazard models. Summary: Multistate models provide a more general and flexible framework that extends beyond the Kaplan-Meier estimator and Cox models. Multistate models allow simultaneous analyses of multiple disease pathways to provide insights into the natural history of complex diseases. We strongly encourage the use of multistate models when analyzing time-to-event data. Supplementary Information: The online version contains supplementary material available at 10.1007/s40471-022-00291-y.

Clinical course of non-alcoholic fatty liver disease and the implications for clinical trial design.

BACKGROUND & AIMS: The predicted risk and timeline to progression to liver-related outcomes in the population with NAFLD are not well-characterized. We aimed to examine the risk and time to progression to cirrhosis, hepatic decompensation and death in a contemporary population over a long follow-up period, to obtain information to guide endpoint selection and sample size calculations for clinical trials on NAFLD-related cirrhosis. METHODS: This is a retrospective study of prospectively collected data in a medical record linkage system, including all adults diagnosed with NAFLD between 1996-2016 by clinical, biochemical and radiological criteria in Olmsted County, Minnesota and followed until 2019. Liver-related outcomes and death were ascertained and validated by individual medical record review. Time and risk of progression from NAFLD to cirrhosis to decompensation and death were assessed using multistate modeling. RESULTS: A total of 5,123 individuals with NAFLD (median age 52 years, 53% women) were followed for a median of 6.4 (range 1-23) years. The risk of progression was as follows: from NAFLD to cirrhosis: 3% in 15 years; compensated cirrhosis to first decompensation: 33% in 4 years (8%/year); first decompensation to ≥2 decompensations: 48% in 2 years. Albumin, bilirubin, non-bleeding esophageal varices and diabetes were independent predictors of decompensation. Among the 575 deaths, 6% were liver related. Therapeutic trials in compensated cirrhosis would require enrolment of a minimum of 2,886 individuals followed for >2 years to detect at least a 15% relative decrease in liver-related endpoints. CONCLUSION: In this population-based cohort with 23 years of longitudinal follow-up, NAFLD was slowly progressive, with liver-related outcomes affecting only a small proportion of people. Large sample sizes and long follow-up are required to detect reductions in liver-related endpoints in clinical trials. LAY SUMMARY: For patients with compensated non-alcoholic steatohepatitis-related cirrhosis, the time spent in this state and the risk of progression to decompensation are not well-known in the population. We examined the clinical course of a large population-based cohort over 23 years of follow-up. We identified that adults with compensated cirrhosis spend a mean time of 4 years in this state and have a 10% per year risk of progression to decompensation or death. The risk of further progression is 3-fold higher in adults with cirrhosis and one decompensating event. These results are reflective of placebo arm risks in drug clinical trials and are essential in the estimation of adequate sample sizes.

CSF phosphorylated tau as an indicator of subsequent tau accumulation.

We evaluated the relationship between baseline CSF p-tau181 and the rate of tau PET change in the temporal meta-ROI and entorhinal cortex (ERC) and how it varied by amyloid level (CSF Aß42 or amyloid PET) among 143 individuals from the Mayo Clinic Study of Aging and Mayo Alzheimer Disease Research Center. Higher CSF p-tau181, lower CSF Aß42, and higher amyloid PET levels were associated with faster rates of tau PET change in both the temporal meta-ROI and ERC. In the temporal meta-ROI, longitudinal tau PET accumulation occurred primarily in participants with abnormal biomarker levels and a diagnosis of dementia, which supports the hypothesis that tau aggregation begins later in the disease process. Compared to the temporal meta-ROI, the ERC showed greater change in tau PET in non-demented participants but less change in later disease stages, supporting ERC as a more sensitive marker of early tau PET changes but with less dynamic range over the disease spectrum. We found both amyloid and CSF p-tau181 were associated with rates of tau PET change but there were some differences in associations by region, amyloid biomarker, and disease stage.

Prognostic utility of systemic inflammatory markers and chronic hepatitis C virus infection status in hepatocellular carcinoma patients treated with local ablation.

BACKGROUND: Hepatocellular carcinoma (HCC) has high incidence and mortality worldwide. Local ablation using radiofrequency ablation (RFA) or microwave ablation (MWA) is potentially curative for early-stage HCC with outcomes comparable to surgical resection. We explored the influence of demographic, clinical, and laboratory factors on outcomes of HCC patients receiving ablation. METHODS: This retrospective cohort study included 221 HCC patients receiving local ablation at Mayo Clinic between January 2000 and October 2018, comprising 140 RFA and 81 MWA. Prognostic factors determining overall survival (OS) and disease-free survival (DFS) were identified using multivariate analysis. RESULTS: There was no clinically significant difference in OS or DFS between RFA and MWA. In multivariate analysis of OS, pre-ablation lymphocyte-monocyte ratio [Hazard ratio (HR) 0.7, 95% confidence interval (CI) 0.58-0.84, P = 0.0001], MELD score [HR 1.12, 95%CI 1.068-1.17, P <  0.0001], tumor number [HR 1.23, 95%CI 1.041-1.46, P = 0.015] and tumor size [HR 1.18, 95%CI 1.015-1.37, P = 0.031] were clinically-significant prognostic factors. Among HCC patients with chronic hepatitis C (HCV) infection, positive HCV PCR at HCC diagnosis was associated with 1.4-fold higher hazard of death, with 5-year survival of 32.8% vs 53.6% in HCV PCR-negative patients. Regarding DFS, pre-ablation lymphocyte-monocyte ratio [HR 0.77, 95%CI 0.66-0.9, P = 0.001], MELD score [HR 1.06, 95%CI 1.022-1.11, P = 0.002], Log2 AFP [HR 1.11, 95%CI 1.033-1.2, P = 0.005], tumor number [HR 1.29, 95%CI 1.078-1.53, P = 0.005] and tumor size [HR 1.25, 95%CI 1.043-1.51 P = 0.016] were independently prognostic. CONCLUSIONS: Pre-ablation systemic inflammation represented by lymphocyte-monocyte ratio is significantly associated with OS and DFS in HCC patients treated with local ablation. HCV viremia is associated with poor OS. Tumor biology represented by tumor number and size are strongly prognostic for OS and DFS while AFP is significantly associated with DFS only.

Long-term associations between amyloid positron emission tomography, sex, apolipoprotein E and incident dementia and mortality among individuals without dementia: hazard ratios and absolute risk.

Dementia and mortality rates rise inexorably with age and consequently interact. However, because of the major logistical difficulties in accounting for both outcomes in a defined population, very little work has examined how risk factors and biomarkers for incident dementia are influenced by competing mortality. The objective of this study was to examine long-term associations between amyloid PET, APOE ɛ4, sex, education and cardiovascular/metabolic conditions, and hazard and absolute risk of dementia and mortality in individuals without dementia at enrolment. Participants were enrolled in the Mayo Clinic Study of Aging, a population-based study of cognitive ageing in Olmsted County, MN, USA. All were without dementia and were age 55-92 years at enrolment and were followed longitudinally. Predictor variables were amyloid PET, APOE ɛ4 status, sex, education, cardiovascular/metabolic conditions and age. The main outcomes were incident dementia and mortality. Multivariable, multi-state models were used to estimate mortality and incident dementia rates and absolute risk of dementia and mortality by predictor variable group. Of the 4984 participants in the study, 4336 (87%) were cognitively unimpaired and 648 (13%) had mild cognitive impairment at enrolment. The median age at enrolment was 75 years; 2463 (49%) were women. The median follow-up time was 9.4 years (7.5 years after PET). High versus normal amyloid (hazard ratio 2.11, 95% confidence interval 1.43-2.79), APOE ɛ4 (women: hazard ratio 2.24, 95% confidence interval 1.80-2.77; men: hazard ratio 1.37, 95% confidence interval 1.09-1.71), older age and two additional cardiovascular/metabolic conditions (hazard ratio 1.37, 95% confidence interval 1.22-1.53) were associated with the increased hazard of dementia (all P < 0.001). Among APOE ɛ4 carriers with elevated amyloid, remaining lifetime risk of dementia at age 65 years was greater in women [74% (95% confidence interval 65-84%) high and 58% (95% confidence interval 52-65%) moderate amyloid], than men [62% (95% confidence interval 52-73%) high and 44% (95% confidence interval 35-53%) moderate amyloid]. Overall, the hazard and absolute risk of dementia varied considerably by predictor group. The absolute risk of dementia associated with predictors characteristic of Alzheimer's disease was greater in women than men while at the same time the combination of APOE ɛ4 non-carrier with normal amyloid was more protective in women than men. This set of findings may be attributed in part to different biological effects and in part to lower mortality rates in women.

Aspirin, Statins, Non-aspirin NSAIDs, Metformin, and the Risk of Biliary Cancer: A Swedish Population-Based Cohort Study.

BACKGROUND: Chemoprevention for biliary tract cancers (BTC), which comprise intrahepatic cholangiocarcinoma (iCCA), extrahepatic cholangiocarcinoma (eCCA), and gallbladder cancer, is controversial. We examined associations between low-dose aspirin, statins, NSAIDs, and metformin with BTC risk. METHODS: We used a population-based cohort of 5.7 million persons over age 18 without personal history of cancer (except nonmelanoma skin cancer), receiving at least one commonly prescribed drug between July 1, 2005, and December 31, 2012, from the Swedish Prescribed Drug Registry. Hazard ratios (HR) were calculated using age-scaled multivariable-adjusted Cox models. RESULTS: 2,160 individuals developed BTC. Low-dose aspirin was not associated with BTC risk [HR, 0.93; 95% confidence interval (CI), 0.81-1.07], iCCA (HR, 1.21; 95% CI, 0.93-1.57), eCCA (HR, 0.80; 95% CI, 0.60-1.07), or gallbladder cancer (HR, 0.87; 95% CI, 0.71-1.06). Statins were associated with lower risk of BTC (HR, 0.66; 95% CI, 0.56-0.78), iCCA (HR, 0.69; 95% CI, 0.50-0.95), eCCA (HR 0.54; 95% CI, 0.38-0.76), and gallbladder cancer (HR, 0.72; 95% CI, 0.57-0.91). For all BTC subtypes, combined low-dose aspirin and statins were not associated with lower risk than statins alone. NSAIDs were associated with higher risk of BTC and its subtypes. Metformin was not associated with BTC risk (HR, 0.98; 95% CI, 0.82-1.18), iCCA (HR, 1.06; 95% CI, 0.77-1.48), eCCA (HR, 1.15; 95% CI, 0.82-1.61), or gallbladder cancer (HR, 0.84; 95% CI, 0.63-1.11). CONCLUSIONS: Statins were associated with a decreased risk of BTC and its subtypes. Low-dose aspirin alone was not associated with a decreased risk, and use of both was not associated with further decrease in risk beyond statins alone. IMPACT: Statins were most consistently associated with a decreased risk of BTC and its subtypes.

Liver stiffness measurement by magnetic resonance elastography is not affected by hepatic steatosis.

OBJECTIVES: To evaluate the relationship between biopsy-assessed hepatic steatosis, magnetic resonance imaging (MRI)-assessed proton density fat fraction (PDFF), and magnetic resonance elastography (MRE)-assessed liver stiffness measurement (LSM), in patients with or at risk for nonalcoholic fatty liver disease (NAFLD). METHODS: A retrospective study was performed, encompassing 256 patients who had a liver biopsy and MRI/MRE examination performed within 1 year. Clinical and laboratory data were retrieved from the electronic medical record. Hepatic steatosis and fibrosis were assessed by histopathological grading/staging. First, we analyzed the diagnostic performance of PDFF for distinguishing hepatic steatosis with the receiver operating characteristic analyses. Second, variables influencing LSM were screened with univariant analyses, then identified with multivariable linear regression. Finally, the potential relationship between PDFF and LSM was assessed with linear regression after adjustment for other influencing factors, in patients with diagnosed steatosis (PDFF ≥ 5%). RESULTS: The diagnostic accuracy of PDFF in distinguishing steatosis grades (S0-3) was above 0.82. No significant difference in LSM was found between patients with S1, S2, and S3 steatosis and between all steatosis grades after patients were grouped according to fibrosis stage. No statistically significant relationship was found between the LSM and PDFF (estimate = - 0.02, p = 0.065) after adjustment for fibrosis stage and age in patients with diagnosed steatosis (PDFF ≥ 5%). CONCLUSIONS: In patients with NAFLD, the severity of hepatic steatosis has no significant influence on the liver stiffness measurement with magnetic resonance elastography. KEY POINTS: • The MRI-based proton density fat fraction provides a quantitative assessment of hepatic steatosis with high accuracy. • No significant effect of hepatic steatosis on MRE-based liver stiffness measurement was found in patients with S1, S2, and S3 steatosis and between all steatosis grades after patients were grouped according to fibrosis stage. • After adjusting for fibrosis stage and age, there was no statistically significant relationship between liver stiffness and proton density fat fraction in patients with hepatic steatosis (p = 0.065).

Natural History of Nonalcoholic Fatty Liver Disease With Normal Body Mass Index: A Population-Based Study.

BACKGROUND & AIMS: The natural history of lean nonalcoholic fatty liver disease (NAFLD) is not well-understood. Consequently, patient counseling and disease management are limited. We aimed to compare the natural history of lean, overweight, and obese NAFLD in a U.S. population with long-term follow-up. METHODS: All adults diagnosed with NAFLD in Olmsted County, MN between 1996 and 2016 were identified, and all subsequent medical events were ascertained using a medical record linkage system. Subjects were divided on the basis of body mass index (BMI) at NAFLD diagnosis into 3 groups: normal, overweight, and obese. The probability to develop cirrhosis, decompensation, malignancies, cardiovascular events, or death among the 3 groups was estimated by using the Aalen-Johansen method, treating death as a competing risk. The impact of BMI categories on these outcomes was explored by using Cox proportional hazards regression analysis. RESULTS: A total of 4834 NAFLD individuals were identified: 414 normal BMI, 1189 overweight, and 3231 obese. Normal BMI NAFLD individuals were characterized by a higher proportion of women (66% vs 47%) and lower prevalence of metabolic comorbidities than the other 2 groups. In reference to obese, those with normal BMI NAFLD had a nonsignificant trend toward lower risk of cirrhosis (hazard ratio [HR], 0.33, 95% confidence interval [CI], 0.1-1.05). There were no significant differences in the risk of decompensation (HR, 0.79; 95% CI, 0.11-5.79), cardiovascular events (HR, 1.05; 95% CI, 0.73-1.51), or malignancy (HR, 0.87; 95% CI, 0.51-1.48). Compared with obese, normal BMI NAFLD had higher risk of all-cause mortality (HR, 1.96; 95% CI, 1.52-2.51). CONCLUSIONS: NAFLD with normal BMI is associated with a healthier metabolic profile and possibly a lower risk of liver disease progression but similar risk of cardiovascular disease and malignancy than obese NAFLD.

Relationships between ß-amyloid and tau in an elderly population: An accelerated failure time model.

Using positron emission tomography (PET)-derived amyloid and tau measurements from 1,495 participants, we explore the evolution of these values over time via an accelerated failure time (AFT) model. The AFT model assumes a shared pattern of progression, but one which is shifted earlier or later in time for each individual; an individual's time shift for amyloid and for tau are assumed to be linked. The resulting pattern for each outcome consists of an earlier indolent phase followed by sharp progression of the accumulation rate. APOE ε4 shifts the amyloid curve leftward (earlier) by 6.1 years, and the tau curve leftward by 2.6 years. Female sex shifts the amyloid curve leftward by 2.4 years and the tau curve leftward by 2.6 years. Per-person shifts (i.e., the individual's deviation from the population mean) for the onset of amyloid accumulation ranged from 13 years earlier to 13 years later (10th to 90th percentile) than average and 11 years earlier to 14 years later for tau, with an estimated correlation of 0.49. The average delay between amyloid increase and tau increase was 13.3 years.

Longitudinal cohorts for harnessing the electronic health record for disease prediction in a US population.

PURPOSE: The depth and breadth of clinical data within electronic health record (EHR) systems paired with innovative machine learning methods can be leveraged to identify novel risk factors for complex diseases. However, analysing the EHR is challenging due to complexity and quality of the data. Therefore, we developed large electronic population-based cohorts with comprehensive harmonised and processed EHR data. PARTICIPANTS: All individuals 30 years of age or older who resided in Olmsted County, Minnesota on 1 January 2006 were identified for the discovery cohort. Algorithms to define a variety of patient characteristics were developed and validated, thus building a comprehensive risk profile for each patient. Patients are followed for incident diseases and ageing-related outcomes. Using the same methods, an independent validation cohort was assembled by identifying all individuals 30 years of age or older who resided in the largely rural 26-county area of southern Minnesota and western Wisconsin on 1 January 2013. FINDINGS TO DATE: For the discovery cohort, 76 255 individuals (median age 49; 53% women) were identified from which a total of 9 644 221 laboratory results; 9 513 840 diagnosis codes; 10 924 291 procedure codes; 1 277 231 outpatient drug prescriptions; 966 136 heart rate measurements and 1 159 836 blood pressure (BP) measurements were retrieved during the baseline time period. The most prevalent conditions in this cohort were hyperlipidaemia, hypertension and arthritis. For the validation cohort, 333 460 individuals (median age 54; 52% women) were identified and to date, a total of 19 926 750 diagnosis codes, 10 527 444 heart rate measurements and 7 356 344 BP measurements were retrieved during baseline. FUTURE PLANS: Using advanced machine learning approaches, these electronic cohorts will be used to identify novel sex-specific risk factors for complex diseases. These approaches will allow us to address several challenges with the use of EHR.