Objective: A negative association between H. pylori and inflammatory bowel disease (IBD) has been previously reported. There were also case reports suggesting a new onset of IBD 6-12 months after H. pylori eradication therapy. In a case-control study we investigated whether previous H. pylori eradication therapy was associated with the risk of developing IBD.

Methods: IBD outpatients with both Crohn´s disease (CD) and ulcerative colitis (UC) were enrolled. Age- and sex-matched blood donors served as controls in a 1:2 fashion. Information on demographics, medical history, previous H. pylori infection and eradication therapy was recorded. Serum samples for H. pylori serology testing (anti-H. pylori-IgG and anti-CagA-IgG) were obtained. Controls that received H. pylori eradication therapy during the 12 months previous to enrollment were excluded.

Results: Overall, 127 IBD patients (CD N= 90; UC N=37) and 254 controls were enrolled. The prevalence of H. pylori infection (positive H. pylori serology and/or previous eradication) in IBD patients and controls was 11% and 23%, respectively (OR 0.4, 95% CI 0.21-0.74, p<0.003). Four patients (3%) developed IBD (3 MC and 1 CU) after receiving successful H. pylori eradication (latency 6-12 months). The rate of previous H. pylori eradication therapy in patents who successively developed IBD was lower but not statistically different from that observed in the control group (OR 0.43, 95% CI 0.14-1.29, p=0.16).

Conclusions: In our study previous H. pylori eradication therapy was not associated with the onset of IBD. Whether in a subgroup of patients, H. pylori eradication therapy may trigger a latent IBD, cannot be excluded.