Incidence and mortality of treated primary Sjogren's syndrome in Taiwan: a population-based study

To estimate the incidence and mortality of treated primary Sjögren's syndrome (pSS) by sex and age group in Taiwan.

We used claims data of the Bureau of National Health Insurance (NHI) of Taiwan from 2005 to 2007 for analysis. According to the NHI, pSS is classified as one of the financially catastrophic illnesses and patients with pSS could be exempted from copayment of all medical costs. To obtain a catastrophic illness certificate (CIC) for pSS, patients are required to meet the criteria of the American-European Consensus Group for pSS, and are reviewed by a committee. Patients approved for receipt of a CIC for pSS for the first time were defined as incident cases of treated pSS.

A total of 3352 incident cases occurred between 2005 and 2007. The estimated mean annual incidence was 6.0 per 100,000 inhabitants (95% CI 5.8-6.2) for both sexes, 11.0 (95% CI 10.6-11.4) for women and 1.1 (95% CI 1.0-1.2) for men, with a female/male ratio of 9.9 (95% CI 8.8-11.1). Incidence increased with age, peaking at age 55-64 years in women and 65-74 years in men. The mortality rate was 33.4 per 1000 case person-years for men and 11.4 for women, with a male/female rate ratio of 2.9 (95% CI 1.7-5.3).

The incidence of treated pSS in women is 10 times that in men. Nevertheless, pSS mortality in men is 3 times that in women.