The Risk of Mild, Moderate, and Severe Infections in IBD patients - A prospective, multicentre observational cohort study (PRIQ).

Background: In light of the growing number of treatment options, the benefit-risk balance of IBD drugs is increasingly important in clinical decision-making. Post-marketing surveillance studies are pivotal to assess infection risk, yet mainly focus on severe infections. This study aimed to assess the incidence and risk factors associated with mild, moderate, and severe infections in IBD patients.

Methods: We previously developed and validated a Patient-Reported Infections Questionnaire (PRIQ) which accurately assesses 15 infection categories with a 3-month recall period. The current prospective, multicentre, observational cohort study was performed between June 1, 2020 and July 1, 2021, enrolling consecutive IBD patients using myIBDcoach. Incidence rates (IR) were calculated for all infections and negative binomial regression was utilized to identify risk factors for infections over time.

Results: In total, 629 IBD patients (n=346 CD, n=283 UC, 58.3% female) were included, completing 2397 PRIQs during 573.8 person-years (PY) of follow-up. This resulted in 991 reported infections and an overall IR of 172.7 per 100PY, predominantly characterized by mild (IR 117.5 per 100PY) and moderate (IR 50.9 per 100PY) infections. Risk factors significantly associated with increased overall infection rates included female sex, higher comorbidity burden, smoking, and specific treatments, such as steroids, immunomodulators, anti-TNF agents, and JAK-inhibitors, with steroids doubling infection risk (IRR 2.02).

Conclusion: Mild and moderate infections are common among IBD patients and are particularly associated with both patient characteristics and specific immunosuppressive treatments. These findings emphasize the need for vigilant monitoring, especially for patients at higher infection risk, and allow for more personalized advice on benefit-risk of IBD treatments.