Frailty Rather Than Age Increases the Risk of Infections in Patients With Inflammatory Bowel Disease Treated With Biologics: An Observational Retrospective Cohort Study

Background Frailty is a multidimensional condition associated with poor clinical outcomes. However, its role in inflammatory bowel disease (IBD) remains largely unexplored, with limited evidence regarding the use of advanced treatments. Our study aimed to address whether the presence of frailty could influence the occurrence of infections in patients with IBD on biological therapy. Methods A retrospective observational study including all adult IBD patients treated with biologics between 2013 and 2019 was conducted at our tertiary referral IBD centre. Frailty was defined according to the Hospital Frailty Risk Score. The primary outcome was to compare the overall rate of infections in frail versus nonfrail patients. Secondary outcomes included the assessment of severe infections in the two groups, the identification of the cumulative risk of developing infections during treatment in both groups, and the identification of predictors of infections. Cox’s proportional hazards regression models and Kaplan–Meier Curves were used for both the primary and the secondary outcomes. Results Among 543 patients (55.4% males, 38.1% > 50 years), 29.7% were classified as frail. A total of 123 infections were recorded, 35 (28.5%) of which were severe. Infections occurred in 48.4% of frail patients versus 11.8% of fit patients ( p < 0.001), and severe infections occurred in 13.7% versus 3.4%, respectively ( p < 0.001). Frailty was independently associated with an increased risk of both any infection (HR 5.81, 95% CI 3.93–8.58, p < 0.001) and severe infection (HR 4.65, 95% CI 2.28–9.47, p < 0.001). At 1 year, 58.5% of frail patients and 93.4% of fit patients had no episodes of any infection. Conclusion Frail IBD patients receiving biologics had a higher overall infection rate than fit patients. Frailty was also a strong predictor of infections in IBD patients on biologics, supporting routine assessment of frailty before and during treatment to improve risk stratification and provide tailored management in this highly vulnerable population.