Outcomes of liver and cardiovascular metabolic diseases among lean vs non-lean individuals with metabolic dysfunction-associated steatotic liver disease

BACKGROUND Cardiovascular and liver metabolic diseases are interconnected conditions, associated with obesity. However, both can occur in lean individuals, and the distinct clinical profiles and outcomes in this population remain poorly defined. AIM To compare liver and cardiovascular outcomes between lean and non-lean individuals with metabolic dysfunction-associated steatotic liver disease (MASLD). METHODS We conducted a systematic review and meta-analysis of studies published in the past 20 years comparing seven outcomes between lean and non-lean with dysfunction-associated steatotic liver disease individuals. A random-effects model was applied to calculate pooled odds ratios (pORs) with 95% confidence intervals (CIs) for the outcomes. RESULTS A total of 31 studies comprising 10735550 participants were included. Non-lean individuals with MASLD had higher odds of liver fibrosis (pOR = 2.0, 95%CI: 1.0, 3.9, P = 0.04) and hepatic steatosis (pOR = 2.1, 95%CI: 1.5, 2.9, P < 0.001) compared to lean individuals with MASLD. Lean individuals with MASLD had lower odds of cirrhosis (pOR = 0.7, 95%CI: 0.5, 0.9, P = 0.007) and hypertension (pOR = 0.7, 95%CI: 0.6, 0.9, P = 0.002) compared to non-lean individuals with MASLD. There was no significant statistical difference in mortality between lean and non-lean MASLD groups (pOR = 1.4, 95%CI: 1.0, 2.0, P = 0.06). Also, no statistically significant differences were found for metabolic dysfunction-associated steatohepatitis (pOR = 1.2, 95%CI: 0.7, 2.0, P = 0.5) and cardiovascular diseases (pOR = 0.9, 95%CI: 0.7, 1.0, P = 0.1). CONCLUSION In our study, lean individuals with MASLD have the similar odds of metabolic dysfunction-associated steatohepatitis, cardiovascular diseases and mortality compared to non-lean MASLD patients. Therefore, there is a need to expand MASLD screening and risk stratification strategies beyond obesity-based metrics alone.