The relationship between chronic H. pylori infection, CagA seropositivity and stroke: meta-analysis

Aims: There is contrasting evidence on the relevance of chronic infection by Helicobacter pylori (H. pylori) as a risk factor for stroke. We performed a meta-analysis of case-control studies to assess association of H. pylori infection and more virulent H. pylori strains, bearing the cytotoxin-associated gene-A (CagA) antigen, with different types of stroke. Methods: Outcome measures were: H. pylori and CagA seroprevalence in (1) patients with stroke versus controls, and (2) patients with stroke due to large vessel stroke versus patients with other types of stroke and controls. Results: Seven cross-sectional, case-control studies were included. Odds ratio for individual case-control studies and pooled OR for the association between H. pylori seropositivity and stroke was 1.49 (95% CI 1.24–1.81), for the association between stroke and anti-CagA positivity was 2.23 (95% CI 1.49–3.36). Patients with large vessel stroke had higher odds for H. pylori infection than patients with other types of stroke (odds ratio 1.65; 95% CI 1.12–2.45), and than controls (odds ratio 1.61; 95% CI 1.13–2.32). Conclusions: Association between H. pylori positivity, anti-CagA positivity and stroke is modest and seems higher with stroke due to large vessel disease. This meta-analysis suggests that the role of CagA positive H. pylori strains in different stroke etiologic subclasses should be the target of future prospective investigation.