P251 Pattern of mortality for patients with axSpA: a retrospective UK database analysis

Abstract

Abstract Background This study characterises mortality for patients with axial spondyloarthritis (axSpA) and compares mortality rates with a matched, non-axSpA population. Methods The Clinical Practice Research Datalink, a large routine primary care database in the UK, was used to conduct this study. Patients with an incident diagnosis of axSpA from 2003-2017 were identified and matched to non-axSpA patients according to age, sex, primary care practice and concurrent practice registration. The date of first axSpA diagnosis defined the index date, and patients were followed up until death or censored at the end of follow up. Crude mortality rates were calculated and time to death from index date was analysed using the Kaplan-Meier estimator. For patients from primary care practices linked to the Office of National Statistics (ONS), cause-specific unadjusted rate ratios are presented. Two adjusted Cox proportional hazard models were conducted: 1) to assess relative mortality between axSpA patients and non-axSpA controls; and 2) to assess disease-specific factors associated with mortality for the axSpA population only. Only patients whose record could be potentially linked to ONS mortality data were included in the cause of death analysis. Results 4,136 incident axSpA cases were identified and matched to non-axSpA controls. Crude mortality rates were 18.9 and 11.5 per 1,000 patient-years, respectively. The most common causes of death in the axSpA cohort were coronary heart disease, cerebrovascular disease and malignant neoplasm of the bronchus and lung (Table 1). For all-cause mortality, there was a significantly increased hazard ratio (HR) of 1.531 (95% confidence interval [CI] 1.291-1.816; P < 0.001) for axSpA vs non-axSpA patients. Age (HR 1.083 [95% CI: 1.074-1.093]; P < 0.001), history of infection (HR 1.358 [95% CI: 1.082-1.705]; P = 0.008), Charlson Comorbidity Index (HR 1.194 [95% CI: 1.137-1.253]; P < 0.001) and current smoker status (HR 1.853 [95% CI: 1.396-2.461]; P < 0.001) were all significantly associated with time to death. Conclusion In this study, we have shown that the presence of axSpA is associated with increased mortality compared with controls. Prior infection, comorbidity and current smoker status were associated with the greatest increased risk of mortality in patients with axSpA. Disclosures C.L.I. Morgan: Other; Employee of: Pharmatelligence. A. White: Shareholder/stock ownership; Novartis. Other; Employee of: Novartis. M. Tomlinson: Consultancies; Novartis. A. Scott: Consultancies; Novartis. H. Tian: Other; Employee of: Novartis.