Background Patients with axial spondyloarthritis (AxSpA) are thought to be at increased risk of cardiovascular disease but it is unknown if they have excess vascular mortality. Ontario has 13.5 million residents and aproximately 25,000 patients with prevalent AxSpA. Provincial health databases provide a richource of reliable information to conduct studies on mortality risk in AxSpA.
Objectives To assess the risk of vascular mortality in AxSpA.
To identify the predictive factors of vascular mortlaity in AS.
Methods We performed a population-based, retrospective cohort study on incident AxSpA patients, age 15 or above, living in Ontario, Canada between April 1995 and March 2011. There were 21,878 SpA cases and 87,504 controls (matched for age, gender and socioeconomic status). The primary outcome was a composite event of cardiovascular or cerebrovascular deaths coded as the primary cause on death certificates. Cox proportional hazards model was used to estimate differences in vascular mortality between cases and controls. Crude and adjusted hazard ratios (HR) were calculated and adjustments were made for coronary and cerebrovascular disease (CAD, CVD), cancer, diabetes, dementia, inflammatory bowel disease, hypertension, chronic kidney disease (CKD) and peripheral vascular disease (PVD). Risk factors for vascular mortality were identified in the SpA cohort.
Results In the AxSpA cohort 53% were male, with a mean age of 46±16 years, and a follow-up of 169,307 patient-years. Follow-up for controls was 692,499 patient-years. Crude and adjusted HR (95%CI) for vascular deaths were 1.49 (1.26-1.77) and 1.36 (1.14-1.63) respectively, indicating a 36-49% higher risk of vascular mortality in AS. Crude HR (95%CI) in males and females were 1.63 (1.31-2.03) and 1.31 (1.00-1.71) respectively. Cases and controls had similar prevalence of CAD, CVD, PVD, dementia and diabetes, but IBD (6% vs 4%), hypertension (24% vs 18%) and CKD (2% vs 0.8%) were more common in SpA (Figure 1). The predictors of vascular death were CAD and CVD but also included age, male sex, low income, CKD and PVD.
Conclusions AxSpA is associated with significant risk of vascular mortality. These new findings should prompt a comprehensive strategy to screen and treat modifiable vascular risk factors in addition to optimal control of disease activity in AxSpA patients.
Disclosure of Interest None declared