The association between vacA or cagA status and eradication outcome of Helicobacter pylori infection: A meta-analysis

BACKGROUND H. pylori virulence factors, especially vacA and cagA are important in gastroduodenal disease pathogenesis and affect cure rates. This meta-analysis aimed to clarify the association between vacA or cagA status and eradication outcome of H. pylori infection. METHODS A literature search was performed using electronic databases to identify studies. Twenty-six prospective studies were determined eligible. Meta-analytical techniques were conducted to calculate eradication rates and pooled relative ratios (RR). RESULTS The eradication rate was greater approximately 10% in vacA s1 compared with vacA s2 infected patients, and the pooled RR was 1.164 (95%CI: 1.040-1.303, P = 0.008). A significant association existed between vacA s1 and higher eradication rates in Europe (RR: 1.203, 95%CI: 1.003-1.442, P = 0.046) and Asia (RR: 1.187, 95%CI: 1.028-1.371, P = 0.020), in triple therapy patients (RR: 1.175, 95%CI: 1.012-1.365, P = 0.035). Eradication rates were similar for vacA m1 and m2 genotypes (RR: 0.981, 95%CI: 0.891-1.080, P = 0.690), whereas they were higher by approximately 8% in cagA-positive compared with cagA-negative infected patients, with a pooled RR of 1.094 (95%CI: 1.025-1.168, P = 0.007). A significant association existed between cagA-positive and increased eradication rates in Europe (RR: 1.138, 95%CI: 1.000-1.295, P = 0.049) and Asia (RR: 1.118, 95%CI: 1.051-1.190, P<0.001), in using PCR (RR: 1.232, 95%CI: 1.142-1.329, P<0.001) and protein chips (RR: 1.200, 95%CI: 1.060-1.359, P = 0.004), in triple therapy patients (RR: 1.090, 95%CI: 1.006-1.181, P = 0.034). CONCLUSIONS Evidence indicates that infection with vacA s1, cagA-positive strains, but not vacA s2, cagA-negative, is more conducive to H. pylori eradication.