Abstract
Objective To examine the mortality rates in hospitalised patients with ankylosing spondylitis (AS), and the association of extra-articular manifestations (EAM) and co-morbidities with mortality rates.
Methods The study was a retrospective population-based cohort study using linked administrative data of hospitalised AS patients (n=1,791) and a matched comparison group (n=8,955). Mortality data for patients were obtained from the Western Australian Death Register. The presence of EAM and co-morbidities were identified from hospital records. Mortality rates were compared between the two groups using Cox proportional hazard models, overall and stratified by a history of EAM, comorbidities and smoking status.
Results Crude mortality rates were significantly higher in AS patients than the comparison group (HR:1.85, 95%CI:1.62-2.12) with excess mortality in the AS group associated with cardiovascular disease (HR:5.32, 95%:3.84-7.35), cancer (HR:1.68, 95%CI:1.27-2.23), external causes (HR:3.92, 95%CI:2.28-6.77) and infections (HR:25.92, 95%CI:7.50-89.56). When patients were stratified by a history of EAM, cardiovascular disease, and smoking the risk of mortality was elevated in both patients with and without each risk factor. Within patients with AS, a history of cardiovascular disease (HR:6.33, 95%CI:4.79-8.38), diabetes (HR:2.81, 95%CI:1.99-3.95), smoking (HR:1.49, 95%CI:1.18-1.89) and EAM (HR:1.62, 95%CI: 1.24–2.11) were associated with an increased risk of mortality.
Conclusion The presence of co-morbidities, EAMs, and smoking contribute to an increased risk of all-cause mortality in hospitalised AS patients compared to the comparison group. These results support the need to prevent or reduce the occurrence of co-morbidity and smoking in AS patients.