Background Giant cell arteritis (GCA) is associated with significant morbidity and mortality, but previous studies on mortality in GCA have yielded conflicting results. Furthermore, mortality trends are largely unknown, particularly in the general population.
Objectives To address this knowledge gap, we evaluated mortality trends in individuals with GCA in a general population-context from January 1, 1997 – December 31, 2012.
Methods Using an administrative health database from the province of British Columbia, Canada (population approximately 4.5 million), we identified all incident cases of GCA and up to 10 non-GCA sex-, age- and entry-time-matched controls. The case definition for GCA included at least one prescription of oral glucocorticoids between one month before and six months after the index date. Study cohorts were divided into two sub-groups based on the year of diagnosis (i.e., 1997–2004 and 2005–2012). Mortality rates were calculated, as well as hazard ratios (HR) using a Cox proportional hazard model. HRs were adjusted for potential confounders (e.g., Charlson's comorbidity index, number of outpatient visits and hospitalizations, cardiovascular drugs, glucocorticoids, cox-2 inhibitors, NSAIDs within 12 months prior to index date).
Results The early cohort (i.e., 1997–2004) of GCA patients had considerably higher mortality rates than the late cohort (i.e., 2005–2012) (i.e., 373.7 vs 87.5 cases per 1000 person-years), while the non-GCA cohort experienced a much smaller improvement in mortality rates between the two time periods (i.e., 70.9 vs 52.0 cases per 1000 person-years). The resulting HRs for mortality for the early and late cohorts were 4.58 (95% CI, 3.70–5.67) and 1.46 (95% CI, 1.16–1.84), respectively. Testing for difference between incident cohorts via an interaction term were all significant.
Conclusions This population-based study shows that survival of GCA patients has improved in recent years, suggesting that new treatment strategies and improved management of GCA and its associated complications has led to significant improvements in GCA-associated mortality.
Acknowledgement This study was funded by the Canadian Arthritis Network, The Arthritis Society of Canada/the British Columbia Lupus Society (Grant 10-SRP-IJD-01) and The Canadian Institutes of Health Research (THC-135235).
Disclosure of Interest None declared