RESEARCH - Influence of steroids on the risk of non-serious infection in RA

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Ann Rheum Dis. 2011 Feb 1. [Epub ahead of print]

The influence of systemic glucocorticoid therapy upon the risk of

non-serious infection in older patients with rheumatoid arthritis: a

nested case-control study.

Dixon WG, Kezouh A, Bernatsky S, Suissa S.

1Arthritis Research UK Epidemiology Unit, Manchester Academic Health

Science Centre,The University of Manchester, Manchester, UK.

Abstract

BACKGROUND: Glucocorticoid therapy is strongly associated with an

elevated risk of serious infections in patients with rheumatoid

arthritis (RA). The association between glucocorticoids and common

non-serious infections (NSI) is not well studied.

METHODS: A cohort of 16 207 patients with RA aged over 65 years was

assembled using administrative data from Quebec. Glucocorticoid and

disease-modifying antirheumatic drug (DMARD) therapy were identified

from drug dispensing records. NSI cases were defined as first

occurrence of a community physician billing code for infection or

community-dispensed anti-infectives. A nested case-control analysis

was performed considering drugs dispensed within 45 days of the index

date, adjusting for age, sex, markers of disease severity, DMARD and

comorbidity.

RESULTS: For 13 634 subjects, a NSI occurred during 28 695

person-years of follow-up, generating an incidence rate of 47.5/100

person-years. The crude rate of NSI in glucocorticoid-exposed and

unexposed person time was 52.4 and 38.8/100 person-years,

respectively. Glucocorticoid therapy was associated with an adjusted

RR of 1.20 (95% CI 1.15 to 1.25). A dose response was seen, the

adjusted RR increasing from 1.10 (<5 mg prednisolone/day) to 1.85 for

doses greater than 20 mg/day. All glucocorticoid risk estimates

(including <5 mg/day) were higher than that seen for methotrexate

(adjusted RR 1.00; 0.95 to 1.04).

CONCLUSION: Glucocorticoid therapy is associated with an increased

risk of NSI. The magnitude of risk increases with dose, and is higher

than that seen with methotrexate, although residual confounding may

exist. While the RR is low at 1.20, the absolute risk is high with one

additional infection seen for every 13 patients treated with

glucocorticoids for 1 year.

PMID: 21285116

http://www.ncbi.nlm.nih.gov/pubmed/21285116

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