SAN DIEGO, CA—Exposure to glucocorticosteroids was associated with a significant increase in mortality, a finding that has “important implications for health care providers and people with arthritis,” results of a population-based cohort study reported at the 2013 ACR/ARHP Annual Meeting.
Diane Lacaille, MD, MHSc, an assistant professor in the Division of Rheumatology at the University of British Columbia and a research scientist at the Arthritis Research Centre of Canada, Vancouver, Canada, and colleagues evaluated the association between exposure to glucocorticosteroids and risk of morality in rheumatoid arthritis (RA).
Using administrative billing data, the investigators assembled a population-based incident RA cohort of all incident cases from January 1996—March 2006 followed until March 2010. Exposure to glucocorticosteroids was defined “as any dispensed prescription for oral glucocorticosteroids during follow-up,” Dr. Lacaille stated. This was measured using time-dependent exposure variables in separate models that represented the current dose (in per 5mg prednisone equivalent), cumulative dose (per 1gm), past cumulative duration of exposure (per 1 year), and current dose (5mg) and cumulative duration (1 year) in the same model.
The sample included 18,215 incident cases of RA. Mean age of the patients was 57.2 years and 66.5% were female. Mean follow-up was 7.1 years, with 128,799 person-years of follow-up. A total of 5326 patients with RA (29.2%) were exposed to glucocorticosteroids and 2881 deaths occurred.
In all models, “exposure to glucocorticosteroids was associated with an increased risk of death,” they reported. Risk of all-cause mortality was 1.22 (95% CI 1.21–1.24) for current dose; 1.11 (95% CI 1.10–1.12) for cumulative dose; 1.30 (95% CI 1.26–1.35) for cumulative duration; and, in the same model, 1.22 (95% CI 1.20–1.24) for current dose and 1.26 (95% CI 1.22–1.31) for cumulative duration (all P<0.0001).
They found that female gender, current use of methotrexate and biologics, and later calendar year of inclusion were all associated with a reduced risk of death. Age, smoking, Charlson comorbidity score, and markers of RA severity were associated with an increased risk of death.
“Limitations of our study are those inherent to observational study, including possible effect of residual or unmeasured confounding, and selection bias from non-random allocation of treatment,” they concluded.