Association Between Remnant Cholesterol and Nonalcoholic Fatty Liver Disease: A Systemic Review and Meta-Analysis

Lipid disorders are related to the risk of nonalcoholic fatty liver disease (NAFLD). Remnant cholesterol (RC), a nonclassical and once-neglected risk factor for NAFLD, has recently received new attention. In this study, we assessed the relationship between the RC levels and NAFLD risk. We searched across PubMed, Web of Science, Embase, Cochrane Library, and China National Knowledge Infrastructure, with no restrictions on publication languages. Retrospective cohort studies and cross-sectional studies were enrolled from the inception of the databases until August 6, 2023. A random-effect model was applied to construct the mean difference, and a 95% confidence interval was applied to assess the relationship between the RC levels and NAFLD risk. We used two methods to estimate RC levels: Calculated-1 subtracts low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol from total cholesterol; Calculated-2 uses the Friedewald formula for LDL-C when triglycerides are <4.0 mmol/L, otherwise directly measured. A total of 265 published studies were selected through preliminary retrieval. Of these, six studies met the inclusion requirements and were enrolled in the meta-analysis. The RC level in the NAFLD group was significantly higher than that in the non-NAFLD group (mean difference: 0.18, 95% confidence interval: 0.10-0.26,