RESEARCH - High disease activity is associated with increased risk of infection in RA

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Ann Rheum Dis. 2011 Feb 2.

High disease activity is associated with an increased risk of

infection in patients with rheumatoid arthritis.

Au K, G, Curtis JR, Kremer JM, Greenberg JD, Strand V, Furst DE;

; on behalf of the CORRONA Investigators.

1Division of Rheumatology, University of California Los Angeles, Los

Angeles, California, USA.

Abstract

OBJECTIVE: To determine the relationship of disease activity to

infections in patients with rheumatoid arthritis (RA).

METHODS: From the CORRONA database, the incidence of

physician-reported infections in RA patients on stable

disease-modifying antirheumatic drug, biological, and corticosteroid

therapy for at least 6 months was ascertained. Two composite measures

of disease activity were defined: clinical disease activity index

(CDAI) and disease activity score 28 (DAS28). Incident rate ratios

(IRR) were calculated using generalised estimating equation Poisson

regression models adjusted for demographics, medications and clinical

factors.

RESULTS: Of 1 6242 RA patients, 6242 were on stable therapy for at

least 6 months and were eligible for analysis. 2282 infections were

reported in the cohort, followed over 7290 patient-years. After

controlling for possible confounders, disease activity was associated

with an increased rate of infections. Each 0.6 unit increase in DAS28

score corresponded to a 4% increased rate of outpatient infections

(IRR 1.04, p=0.01) and a 25% increased rate of infections requiring

hospitalisation (IRR 1.25, p=0.03). There was a dichotomy in the

relationship between infections and CDAI scores. For CDAI <10 (mild

disease activity) patients had a 12% increased rate of outpatient

infections with each 5 unit increase in CDAI score (IRR 1.12,

p=0.003). At CDAI scores ≥10, there was no further increase in the

rate of outpatient infections associated with higher disease activity.

The relationship of CDAI to hospitalised infections showed similar

trends to outpatient data but did not reach statistical significance

after multivariate analysis (CDAI <10: IRR 1.56, p=0.08).

CONCLUSIONS: In this large cohort of RA patients, higher disease

activity was associated with a higher probability of developing

infections.

PMID: 21288960

http://www.ncbi.nlm.nih.gov/pubmed/21288960

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