Lipoprotein (a) and inflammatory bowel disease: a systematic review and meta-analysis.

Background: Lipid profile alterations have been reported in patients with inflammatory bowel disease (IBD). Our aim was to systematically investigate all relevant evidence on the association between lipoprotein (a) [Lp(a)] and IBD. Methods: We searched PubMed and Cochrane Library databases (up to 30 December 2024) for studies with evidence on Lp(a) in patients with IBD. A meta-analysis was performed to evaluate the mean differences (MD) in Lp(a) between patients with Crohn's disease (CD) or ulcerative colitis (UC), and healthy controls (HC). Results: The literature search identified 11 studies (2687 participants) investigating the lipid profile of patients with IBD; however, only 6 studies were used for the meta-analysis. Overall, 1978 participants were included in the meta-analysis, of whom 1196 were IBD patients and 782 were HC. The pooled analysis from 4 studies showed that CD patients had significantly higher Lp(a) levels compared to HC (MD 18.36 mg/dL, 95% confidence interval [CI] 14.53-22.20; P<0.001). Similarly, a pooled analysis from 4 studies showed that UC patients had higher Lp(a) levels compared to HC (MD 7.32 mg/dL, 95% CI 2.85-11.79; P=0.001). A pooled analysis of 3 studies revealed a non-significant difference in Lp(a) levels between CD and UC patients. In subgroup analyses based on disease activity, CD patients with active disease exhibited significantly higher Lp(a) levels compared to those with inactive disease. No significant difference was observed in UC patients stratified by disease activity. Conclusions: Lp(a) levels are significantly higher in both CD and UC patients compared to HC. Therefore, Lp(a) evaluation is advisable when assessing IBD patients.