Predictors of Survival and Causes of Death in Japanese Patients with Systemic Sclerosis

Objective. To clarify the mortality rates, causes of death, and contributing clinical factors in Japanese patients with systemic sclerosis (SSc). Methods. A cohort of 405 patients with SSc, who attended our institution during the period 1973 to 2008, was retrospectively analyzed until the end of 2009. Clinical data were obtained from medical records or autopsy reports. Results. The 405 patients with SSc consisted of 310 (76.5%) survivors, 86 (21.2%) who died, and 9 who were lost to followup. Diffuse cutaneous SSc and involvement of organs other than the gastrointestinal tract were more frequent in patients who died, and were associated with a worse prognosis according to Kaplan-Meier analysis. Female sex, limited cutaneous SSc, anticentromere antibody (ACA), and overlap with Sjogren's syndrome (SS) were factors favoring a better prognosis, while overlap with myositis contributed to a poor prognosis. The overall 10-year survival rate was 88%. The patients with SSc had a significantly higher mortality than the general population (standardized mortality ratio 2.76), but the patients with ACA or overlapping SS did not. The most common causes of death were unknown ones including sudden death, followed by malignancy and infection. In patients with pulmonary arterial hypertension, sudden death was the most common cause of mortality. Conclusion. The overall mortality rate of patients with SSc was higher than that of the general population, probably because of poor prognostic factors including organ involvement. These factors should be carefully monitored during followup. (First Release July 15 2011; J Rheumatol 2011;38:1931-9; doi:10.3899/jrheum.100298)