Vascular endothelial growth factor in inflammatory bowel disease: A systematic review and meta-analysis.

Aim: Vascular endothelial growth factor (VEGF) is linked to inflammation and angiogenesis, indicating a possible role in inflammatory bowel disease (IBD) and its main clinical manifestations, Crohn's disease (CD) and ulcerative colitis (UC). This systematic review and meta-analysis investigated studies assessing circulating VEGF concentrations in IBD patients and healthy controls, considering the effect of IBD type, sample type and geographical location.

Methods: A systematic search identified 18 studies (28 group comparators) investigating 1741 IBD patients and 1291 controls. Data were extracted and analysed using standardized mean differences (SMD) with 95% confidence intervals (CI).

Results: VEGF concentrations were significantly higher in IBD patients (SMD = .71, 95% CI .38 to 1.04; p < .001). UC patients showed higher VEGF concentrations than CD patients. Serum samples indicated significant VEGF elevations, unlike plasma samples. Significant VEGF increases were observed in studies conducted in Western Europe and Asia, but not in Eastern Europe. No significant differences were found between active and inactive disease.

Conclusions: VEGF concentrations are elevated in IBD patients, with variations by disease type, sample type and geography. However, VEGF is not a reliable marker of disease activity. Future research should standardize methods and explore regional influences to enhance VEGF's clinical utility as a biomarker of IBD.