AB0666 ALL-CAUSE AND CAUSE-SPECIFIC MORTALITY TREND IN PATIENTS WITH SYSTEMIC SCLEROSIS: A POPULATION-BASED STUDY
Authors: Hyein Kim, LI Lingyi, Eric C. Sayre, Antonio Aviña
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background</h3> Systemic sclerosis (SSc) is a disease with one of the highest mortality rates among connective tissue diseases with 5-year survival ranging from 68-88%[1]. Recent research has shown an improvement in survival for some rheumatic diseases at the population level [2, 3]. Contemporary data on mortality trends in SSc is scarse, especially at the general population level. <h3>Objectives</h3> 1) to investigate all-cause and cause-specific mortality in patients with newly diagnosed systemic sclerosis (SSc) compared to the general population. 2) to assess mortality trends between 2 calendar time periods, 1997–2004 and 2005–2012 <h3>Methods</h3> Using an administrative health database, we compared all patients with new diagnosis of SSc with non-SSc individuals randomly selected from the general population matched for sex, age, and time of entry into the study. The study cohorts were divided into 2 groups based on the year of diagnosis ("early cohort [1997–2004] and "late cohort" [2005–2012]). The outcome was death (all-cause and cause specific including cancer, cardiovascular disease [CVD], infections, renal disease, pulmonary disease and other causes) during the follow-up period. Hazard ratios (HR) were estimated using Cox proportional hazards models, first adjusted for age, sex, and entry cohort time and then adjusted for selected baseline covariates (health care resource utilization, medications, pre-existing comorbidities, and socioeconomic status), based on a purposeful selection algorithm. <h3>Results</h3> We included 874 patients with SSc (83.6% female and mean age of 54.19 in the early cohort, and 81.7% female and mean age of 55.32 in the late cohort) and 8,740 non-SSc individuals in this study, contributing 4,083.8 and 47,515.8 person-years of follow-up, respectively. We observed 168 deaths in the SSc cohort, and 504 deaths occurred in the non-SSc cohort during the follow-up. Overall, the age-, sex-, and entry time–adjusted all-cause mortality HR in the SSc cohort was 4.47 (95% CI 3.72–5.37), and the fully adjusted remained significant [HR=2.87 (95% CI 2.35-3.50)]. Moreover, there was excess mortality due to CVD-related causes in the age-, sex-, and entry time–adjusted model (HR= 2.65 [95% CI 1.68 – 4.18]), but it did not persist in the fully adjusted model (HR= 1.52 [95% CI 0.93-2.48]). There was no significant difference in other cause-specific mortalities, including cancer mortality (HR=0.91 [95% CI 0.56-1.49]). As a consequence of the residual disclosure policy of Population Data BC to ensure patient confidentiality, we were not allowed to report on the deaths due to infection, renal or pulmonary disease, as &lt;5 deaths were associated with each outcome. There was no improvement in all-cause mortality between the early and late cohort (fully adjusted HR= 3.73 and 95% CI 2.49-5.59; HR 2.51 and 95% CI 1.88-3.34, respectively). <h3>Conclusion</h3> This population-based study showed that people with SSc have a 3-fold increase risk of death when compared with the general population. The risk of death has not improved over time and this calls for further research to close this gap. <h3>References</h3> [1] Nikpour M, Baron M. Mortality in systemic sclerosis: lessons learned from population-based and observational cohort studies. Curr Opin Rheumatol. 2014;26(2):131-137. [2] Tan, J. A., Choi, H. K., Xie, H., Sayre, E. C., Esdaile, J. M. And aviña‐Zubieta, J. A. All‐Causeand Cause‐Specific Mortality in Patients with Granulomatosis with Polyangiitis: a Population‐Based Study. Arthritis Care Res. 2019. 71: 155-163. [3] Zhang Y, Lu N, Peloquin C, et al. Improved survival in rheumatoid arthritis: a general population-based cohort study annals of the Rheumatic Diseases2017;76:408-413. <h3>Disclosure of interests</h3> None declared