Determinants of morbidity and mortality of systemic sclerosis in Canada

Objectives: To describe the morbidity and mortality in Canadian scleroderma (SSc) patients focusing on gender, SSc type, and organ-specific prognosis in a cohort of patients seen from 1994 to 2004 in a Southwestern Ontario SSc clinic. We also compared this cohort to data from the literature, which showed that mean survival in recent studies has risen to 72 months versus 48 months in earlier studies.

Methods: This was a cohort study of all SSc patients followed at 1 rheumatology center. Data were abstracted by chart review and entered into a database. The demographic and clinical characteristics of SSc patients were compared between those who survived versus those who died over the 10-year follow-up period. Five- and 10-year survival rates were compared between cohort subsets (sex, diffuse/limited disease type, and organ involvement including the following: scleroderma renal crisis, interstitial lung disease (ILD), hypertension, cardiac, gastrointestinal involvement, pulmonary arterial hypertension, and antinuclear antibody positivity).

Results: One hundred eighty-five subjects (158 women), 63% with limited cutaneous SSc, were included. The mean disease duration until last visit or death was 9.1 years (7.9 years in diffuse and 9.8 years in limited). Although more women had either subtype, men were more likely to have diffuse cutaneous SSc (dcSSc) than women (67% of men had dcSSc versus 32% of women, P = 0.0009), and to have an earlier mean age of diagnosis (41.3 +/- 2.8 years old versus 49.7 +/- 1.2 years, P = 0.006). Overall mortality was 23%; 22% of men (n = 6) and 23% of women (n = 36) were deceased. The 5-year survival was 90% (95% for limited and 81% for diffuse) and the 10-year survival was 82% (92% for limited and 65% for diffuse). Deceased persons were more likely to have had dcSSc (P = 0.03), cardiac disease (P < 0.0001), ILD (P = 0.006), gastrointestinal disease (P = 0.01), and systemic hypertension (P = 0.009). Four of 13 patients with scleroderma renal crisis died. Survival analyses demonstrated that persons with dcSSc (P = 0.001), cardiac disease (P < 0.0001), and hypertension (P = 0.01) had worse survival rates than their counterparts without these disorders. The primary cause of death was ascertained for 33 of the 42 deceased individuals and included the following: pulmonary arterial hypertension (n = 5), renal complications (n = 9), ILD (n = 10), and cardiac complications (n = 9). There appears to be a trend toward longer survival of scleroderma patients over the past few decades.

Conclusions: We conclude that cardiac involvement, dcSSc, and hypertension are associated with worse survival, and survival of patients with scleroderma is improving compared with older reports in the literature.