Need for a three-focused approach to nonalcoholic fatty liver disease

Abstract

We read with interest the reviews by Ghouri et al. 1 and Martinez et al. 2 Ghouri et al. analyzed the association of nonalcoholic fatty liver disease (NAFLD) with cardiovascular disease (CVD) and concluded that although a diagnosis of NAFLD should prompt diabetes screening, it is insufficient for considering patients to be at high risk for CVD. Martinez et al. evaluated noninvasive methods for assessing liver fibrosis and recommended that those tests with the highest diagnostic accuracy be validated against liver biopsy to facilitate their implementation in clinical practice.We meta-analyzed prospective data regarding the natural history of NAFLD and studies assessing the diagnostic accuracy of noninvasive methods for liver disease severity against liver biopsy in NAFLD, and we reached the following conclusions 3 :1. The two NAFLD histological subtypes, simple steatosis (SS) and nonalcoholic steatohepatitis (NASH), have different risks of liver-related complications: SS progresses to cirrhosis in less than 5% of cases; NASH progresses to cirrhosis in 10% to 15% of cases over 10 years and in 25% to 30% of cases in the presence of advanced fibrosis. 2. NAFLD patients have a 1.44-to 2.05-fold higher rate of CVD (depending on whether the diagnosis is based on an aminotransferase elevation or radiological/histological criteria) than the general population; restricting the analysis to studies adjusting for metabolic syndrome did not change the risk. Importantly, CVD mortality did not differ among NAFLD histological subtypes. ; restricting the analysis to studies adjusting for metabolic syndrome did not change the risk. Whether the risk of diabetes differs among NAFLD histological subtypes remains unclear: in a communitybased study, the 13-year incidence of diabetes was 2.98-fold higher in NASH patients versus SS patients. 3According to our analysis, a diagnosis of NAFLD should prompt a thorough three-focus assessment of cardiovascular, metabolic, and liver-related risks (Table 1). 4 Liver-related risk assessment remains problematic because it requires liver histology. Three noninvasive methods have been extensively validated: enzyme-linked immunosorbent assay-detected cytokeratin 18 fragments (9 studies enrolling 856 participants) for the detection of NASH and the NAFLD fibrosis score (13 studies enrolling 3064 participants) and FibroScan (6 studies enrolling 563 participants) for the detection of advanced fibrosis. We believe that these methods should be promptly implemented in diagnostic algorithms to select patients for liver biopsy in routine clinical practice while we continue to search for the ideal noninvasive marker.

Nonalcoholic steatohepatitis versus steatosis: Adipose tissue insulin resistance and dysfunctional response to fat ingestion predict liver injury and altered glucose and lipoprotein metabolism

“…Our data provide also a rationale for prospectively evaluating simple, fasting adipose tissue dysfunction indices, such as adipose IR index, as a screening tool for individuating NAFLD patients at increased overall health‐related risk in larger independent cohorts of unselected NAFLD patients 46, 47…”

Impact of current treatments on liver disease, glucose metabolism and cardiovascular risk in non-alcoholic fatty liver disease (NAFLD): a systematic review and meta-analysis of randomised trials

“…Concerning cardio-metabolic risk of NAFLD, it is currently unclear whether NAFLD determines or is just a marker of associated cardio-metabolic abnormalities, and a comprehensive cardio-metabolic profiling of these patients may help predicting the impact of proposed treatments on cardio-metabolic outcomes [129]. As an example, HbA 1c (reported in only 22% of RCTs; Table 1) is emerging as a robust marker not only of recent glycaemic control in diabetes, but also of the risk of developing diabetes and CVD in diabetic and non-diabetic individuals [130,131].…”

Obstructive Sleep Apnea-Hypopnea Syndrome and Nonalcoholic Fatty Liver Disease: Emerging Evidence and Mechanisms

“…Furthermore, as OSAS and obesity often coexist and share common molecular mechanisms to lead to liver and cardio-metabolic disease, it will be important to clarify their relative importance in the pathogenesis of liver and cardio-metabolic disease in NAFLD patients. 131 This is a relevant issue to address when deciding which target to pursue, whether vigorous weight loss or maximal adherence to CPAP treatment, to achieve the greatest clinical benefit: within this context, it should be mentioned that the improvement of glycemic outcomes with CPAP treatment has been shown to be less marked in obese than in nonobese patients, 98,132 leading to speculate that OSAS may have only a minimal impact on glucose metabolism in the setting of marked obesity. 133 One common strategy to improve clinical trials design may be to match patients with and without OSAS for BMI and abdominal adiposity indices, to control for the effects of visceral and subcutaneous fat on liver and cardio-metabolic disease.…”