Trends in mortality in patients with systemic sclerosis over 40 years: a systematic review and meta-analysis of cohort studies

Objective. SSc is known as the most severe connective tissue disorder, and to be associated with a high mortality risk. Some improvements in therapy for SSc have been achieved in recent years and some preliminary data have suggested an improvement in patient survival. Thus, we set out to determine whether mortality rate in SSc patients has decreased over the past 40 years through a meta-analysis of cohort studies. Methods. We performed a systematic review and a meta-analysis of literature in MEDLINE and Embase databases from January 1960 to June 2010. All cohort studies reporting on SSc mortality were analysed. We then calculated pooled standardized mortality ratios (SMRs) of SSc mortality and calculated their changes over time using meta-regression analysis. Results. Nine studies were included, corresponding to a total of 2691 SSc patients. The pooled SMR was 3.53 [95% CI 3.03, 4.11, P < 0.0001; I-2 = 93%, P(het) = 0.001]. Mid-cohort year ranged from 1977 to 1995 (before 1980: two studies; 1980-90: five studies; and after 1990: two studies): adjusted meta-regression analysis did not show significant change in SMR over time (P = 0.523). Among 732 deaths, heart involvement was the most frequent cause of deaths (29%) followed by lung involvement. Conclusion. Our results confirm that SSc is a devastating condition as reflected by a pooled SMR of 3.5. Additionally, SMR has not significantly changed over the past 40 years. Further studies are needed to assess the effect of the most recent available therapies on mortality in SSc.