Associations of liver fat content with cardiometabolic phenotypes and outcomes in a multi-ethnic population: Results from the Dallas Heart Study.

AIMS: To evaluate the associations between liver fat content and cardiometabolic parameters to explore potential threshold values that define metabolically healthy liver fat content, and to examine the association of liver fat content with cardiovascular events as well as its longitudinal progression. METHODS: Participants in the Dallas Heart Study underwent clinical evaluation, including laboratory testing, and liver fat quantification by magnetic resonance spectroscopy (MRS) at baseline (N = 2287) and at follow-up (N = 343) after a mean of 7.3 years. Cardiovascular events were adjudicated (>12 years). RESULTS: The mean age at study entry was 44 years, 47% of participants were men, and 48% were African American. The following cardiometabolic biomarkers worsened across liver fat quintiles (P < 0.0001): body mass index (BMI); waist circumference; prevalence of hypertension; prevalence of diabetes; cholesterol, triglyceride, high-sensitivity C-reactive protein (CRP), leptin and fasting glucose levels; homeostatic model assessment of insulin resistance index (HOMA-IR); coronary artery calcium score; visceral adipose tissue; abdominal subcutaneous adipose tissue; and lower body subcutaneous adipose tissue. Cardiovascular events were comparable across groups defined by tertile of baseline liver fat content. Change in BMI (R = 0.40), waist circumference (R = 0.35), CRP (R = 0.31), alanine aminotransferase (R = 0.27), HOMA-IR (R = 0.26), aspartate transaminase (R = 0.15) and triglycerides (R = 0.12) significantly correlated with change in liver fat content (P < 0.01 for all). CONCLUSION: Clinically relevant metabolic abnormalities were higher across quintiles of liver fat, with increases noted well within normal liver fat ranges, but cardiovascular events were not associated with liver fat content. Longitudinal changes in metabolic parameters, especially adiposity-related parameters, were correlated with change in liver fat content.

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.