Sine scleroderma, limited cutaneous, and diffused cutaneous systemic sclerosis survival and predictors of mortality

Background Systemic sclerosis (SSc) is associated with a variability of mortality rates in the literature. Objective To determine the mortality and its predictors in a long-term follow-up of a bi-centric cohort of SSc patients. Methods A retrospective observational study by systematically analyzing the medical records of patients diagnosed with SSc in Toulouse University Hospital and Ducuing Hospital. Standardized Mortality Ratio (SMR), mortality at 1, 3, 5, 10, and 15 years of disease and causes of death were described. Predictors of mortality using Cox regression were assessed. Results Three hundred seventy-five patients were included: 63 with diffuse cutaneous SSc, 279 with limited cutaneous SSc, and 33 with sine scleroderma. The SMR ratio was 1.88 (95% CI 1.46–1.97). The overall survival rates were 97.6% at 1 year, 93.4% at 3 years, 87.1% at 5 years, 77.9% at 10 years, and 61.3% at 15 years. Sixty-nine deaths were recorded. 46.4% were SSc related deaths secondary to interstitial lung disease (ILD) (34.4%), pulmonary hypertension (31.2%), and digestive tract involvement (18.8%). 53.6% were non-related to SSc: cardiovascular disorders (37.8%) and various infections (35.1%) largely distanced those from cancer (13.5%). Four significant independent predictive factors were identified: carbon monoxide diffusing capacity (DLCO) < 70% (HR=3.01; p =0.0053), C-reactive protein (CRP) >5 mg/l (HR=2.13; p =0.0174), cardiac involvement (HR=2.86; p =0.0012), and the fact of being male (HR=3.25; p =0.0004). Conclusion Long-term data confirmed high mortality of SSc. Male sex, DLCO <70%, cardiac involvement, and CRP> 5mg/l were identified as independent predictors of mortality.