Pretreatment Frailty Is Independently Associated With Increased Risk of Infections After Immunosuppression in Patients With Inflammatory Bowel Diseases

Abstract

Background & aims: Infections are an important adverse effect of immunosuppression for treatment of inflammatory bowel diseases (IBDs). However, risk of infection cannot be sufficiently determined based on patients' ages or comorbidities. Frailty has been associated with outcomes of patients with other inflammatory diseases. We aimed to determine the association between frailty and risk of infections after immunosuppression for IBD.

Methods: We performed a cohort study of 11,001 patients with IBD, using a validated frailty definition based on International Classification of Disease codes to identify patients who were frail vs fit in the 2 years before initiation of an anti-tumor necrosis factor (TNF) or immunomodulator therapy, from 1996 through 2010. Our primary outcome was an infection in the first year after treatment. We constructed multivariable logistic regression models, adjusting for clinically pertinent confounders (age, comorbidities, steroid use, and combination therapy) to determine the association between frailty and posttreatment infections.

Results: There were 1299 patients treated with an anti-TNF agent and 2676 patients treated with an immunomodulator. In this cohort, 5% of patients who received anti-TNF therapy and 7% of patients who received an immunomodulator were frail in the 2 years before immunosuppression. Frail patients were older and had more comorbidities. Higher proportions of frail patients developed infections after treatment (19% after TNF and 17% after immunomodulators) compared with fit patients (9% after TNF and 7% after immunomodulators; P < .01 for frail vs fit in both groups). Frail patients had an increased risk of infection after we adjusted for age, comorbidities, and concomitant medications (anti-TNF adjusted odds ratio, 2.05 [95% confidence interval, 1.07-3.93] and immunomodulator adjusted odds ratio, 1.81 [95% confidence interval, 1.22-2.70]).

Conclusions: Frailty was associated with infections after immunosuppression in patients with IBD after we adjust for age and comorbidities. Systematic assessment and strategies to improve frailty might reduce infection risk in patients with IBD.

Keywords: Aging; Immunosuppression; Side Effect; Thiopurine.