Gut Microbiota Associated With Hyperlipidemia: A Systematic Review and Meta-Analysis.

BACKGROUND AND AIMS: Hyperlipidemia (HLD) is a major risk factor for cardiovascular disease. Increasing evidence suggests that gut microbiota may influence lipid metabolism, although findings remain heterogeneous. We conducted a systematic review and meta-analysis to synthesize differences in gut microbiota characteristics between individuals with HLD and healthy controls and to summarize reported associations between microbial taxa and plasma lipid levels. METHODS: This systematic review and meta-analysis followed Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines (International Prospective Register of Systematic Reviews number: CRD42024549784). PubMed, Embase, Scopus, Web of Science, Clinicaltrials.gov, Google Scholar, and Science.gov were searched for case-control or cross-sectional studies assessing gut microbiota composition in HLD. Alpha diversity was pooled as standardized mean differences, while beta diversity, taxonomic differences, and microbiota-lipid associations were synthesized qualitatively. Exploratory meta-regression analyses evaluated study-level associations between selected taxa and lipid parameters with separate adjustment for age, body mass index, and sex. RESULTS: Ten studies comprising 561 HLD patients and 1165 controls were included. Pooled alpha diversity indices showed no significant differences between groups, and beta diversity analyses revealed no consistent separation in overall microbial community composition. At the taxonomic level, short-chain fatty acid- and bile salt hydrolase-producing genera, including Faecalibacterium, Parabacteroides, and Roseburia, were consistently reported as less abundant in HLD. Exploratory correlation and meta-regression analyses identified heterogeneous associations between selected genera and circulating lipid parameters. CONCLUSION: Current evidence does not consistently support global gut microbiota diversity as a discriminator of HLD status. However, recurrent associations involving specific microbial taxa suggest that taxon- and function-focused analyses may be more informative than diversity metrics alone. Longitudinal, interventional, and multi-omics studies are needed to clarify causality and clinical relevance.