Session Information
Date: Saturday, November 6, 2021
Session Title: Vasculitis – ANCA-Associated Poster (0414–0436)
Session Type: Poster Session A
Session Time: 8:30AM-10:30AM
Background/Purpose: Antineutrophil cytoplasm antibody (ANCA)-associated vasculitides (AAV) are a group of multisystem inflammatory diseases of the small blood vessels. Infections are serious complications in AAV and often associated with premature mortality. Existing studies on the risk of infection in AAV patients and relative risk when compared to the general population suffer from small sample sizes, selected hospitalized samples and lack of control of potential confounders. To evaluate the independent effect of AAV on the risk of severe infection and infection-related mortality.
Methods: Using administrative data from British Columbia, Canada and a previously validated AAV case definition, we conducted an age- and gender- matched cohort study of all patients with incident AAV between January 1, 1997 and March 31, 2015. The non-AAV individuals were randomly selected from the general population and 10:1 matched to the AAV patients on age, sex and AAV index year. Primary outcome was the first severe infection after AAV onset necessitating hospitalization or occurring during hospitalization. Secondary outcomes were infection-related mortality and total number of severe infections. To evaluate the relative risk of severe infection outcomes for AAV patients relative to general controls, we used: 1) Cox proportional hazard models to compute hazard ratios for the first severe infection as well as for the infection-related mortality; 2) Poisson regression to compute the rate ratios for total counts of infections. These analyses were controlled for the baseline variables listed in Table 1 to assess independent effects of AAV on infection outcomes.
Results: We identified 559 AAV patients and matched them with 5,590 non-AAV individuals from the general population (57% females, mean age 54), yielding 187 and 510 first severe infections (Table 2) during 2,603 and 36，111 person-years follow-up, respectively. The crude incidence rate ratios were 4.85, 3.72 and 5.08 for first severe infection, infection-related mortality and total counts of infections, respectively. After adjusting for all confounders, the independent effect of AAV on the risk of for first severe infection, infection-related mortality and total number of severe infections was 3.77, 3.84 and 3.29, respectively.
Conclusion: In this population-based study, we found AAV was associated with increased risks of first severe infection (3.8-fold), infection-related mortality (3.8-fold) and a greater total number of severe infections (3.3-fold). This highlights the higher risks of infection in AAV patients.
*All baseline characteristics were measured over one year prior to the start of follow-up except that age was measured at the start date of the follow-up.
*Adjusted for covariates listed in Table 1.
To cite this abstract in AMA style:
Zhao K, Xie H, Esdaile J, Avina-Zubieta J. Increased Risk of Severe Infections and Mortality in Patients with Newly Diagnosed Anti-neutrophil Cytoplasmic Antibody–associated Vasculitis: A Population-based Study [abstract]. Arthritis Rheumatol. 2021; 73 (suppl 9). https://acrabstracts.org/abstract/increased-risk-of-severe-infections-and-mortality-in-patients-with-newly-diagnosed-anti-neutrophil-cytoplasmic-antibody-associated-vasculitis-a-population-based-study/. Accessed January 30, 2023.« Back to ACR Convergence 2021
ACR Meeting Abstracts - https://acrabstracts.org/abstract/increased-risk-of-severe-infections-and-mortality-in-patients-with-newly-diagnosed-anti-neutrophil-cytoplasmic-antibody-associated-vasculitis-a-population-based-study/