Epidemiology and mortality of systemic sclerosis: a nationwide population study in Taiwan

Objectives: There have been few nationwide population studies of systemic sclerosis (SSc). We describe the epidemiological features of SSc in Taiwan. Methods: The catastrophic illness registry of the Taiwan National Health Insurance Research Dataset (NHIRD) and the National Death Registry of Taiwan were used to calculate estimates of the incidence, prevalence, and mortality of SSc. Results: A total of 1479 persons (325 males, 1154 females) with incident SSc were enrolled in the study. The annual incidence of SSc in Taiwan was found to be 10.9 cases (4.7 males, 17.4 females) per million population. During 2002-2007, the mean prevalence was 56.3 cases per million population. There were 204 deaths (70 males, 134 females) during the study period; 1-, 2-, and 5-year survival rates were 94.9, 92.0, and 83.2%%, respectively. SSc patients had a standardized mortality ratio (SMR) of 3.24 [95%% confidence interval (CI) 2.82-3.71] for all-cause mortality, as compared with the national population in 2002. There was excess mortality from neoplasms (SMR 1.50, 95%% CI 1.03-2.11), cardiovascular diseases (2.23, 1.52-3.16), kidney disease (4.67, 2.66-7.64), gastrointestinal diseases (2.50, 1.27-4.46), and pulmonary diseases (3.20, 1.89-5.09). In addition to male sex and older age, cancer and end-stage renal disease (ESRD) diagnosis were risk factors for death, with hazard ratios (HRs) of 2.71 (95%% CI 1.27-5.76) and 2.59 (1.14-5.90), respectively. Conclusion: SSc patients had a threefold greater risk of all-cause mortality than the general population of Taiwan. Male sex, older age, diagnosis of cancer, and ESRD were risk factors for death.