Associations of composite lipid indices with carotid atherosclerosis-related outcomes: A systematic review and meta-analysis focused on AIP and VAI

Carotid atherosclerosis and carotid plaque are key contributors to ischemic stroke pathology and cardiovascular disease. Composite lipid indices, including the Atherogenic Index of Plasma (AIP), Visceral Adiposity Index (VAI), and Lipid Accumulation Product (LAP), are biomarkers reflecting dyslipidemia, visceral adiposity, and metabolic dysfunction. However, evidence linking these indices to carotid atherosclerosis-related outcomes remains contradictory. This study aimed to evaluate the associations of AIP, VAI, and LAP with carotid atherosclerosis and carotid plaque. PubMed, Embase, Web of Science, and the Cochrane Library were searched from database inception to May 2025. Observational studies reporting associations between composite lipid indices and carotid atherosclerosis or carotid plaque were included. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were extracted, and random-effects models were employed. For each lipid index, quantitative synthesis was conducted independently; AIP and VAI were examined as separate meta-analytic groups, while LAP was summarized descriptively because only one eligible study was available. Seven observational studies involving 97,573 participants were included (44,890 men and 52,683 women). AIP findings were reported in four studies, VAI in three, and LAP in one. The pooled analysis indicated a significant association between AIP and carotid plaque incidence (OR = 1.30, 95% CI: 1.18-1.44). VAI was also significantly associated with carotid atherosclerosis (OR = 1.48, 95% CI: 1.17-1.87). LAP was reported in only one study, with an OR of 1.43 (95% CI: 1.29-1.58), and was presented descriptively. In AIP subgroup analyses, significant associations were observed across carotid plaque type, study design, and sample-size strata. Sex-stratified analysis for VAI revealed a significant association in men but not in women; however, this finding should be interpreted cautiously. This systematic review and meta-analysis suggest that AIP and VAI are significantly associated with carotid atherosclerosis-related outcomes and may serve as useful supplementary metabolic markers for carotid atherosclerosis risk assessment. LAP showed a positive association in the single available study, but its clinical relevance requires further validation. Considering the small number of studies and the observational nature of the data, further large-scale prospective studies are required to corroborate these findings. The study protocol was registered with the International Platform of Registered Systematic Review and Meta-analysis Protocols (INPLASY) database (registration number: INPLASY202550082).