Funding source This research was supported by grants from the Ministry of Education of the Republic of China, Taiwan (Project No. EMRPD170101) and Chang Gung Memorial Hospital (Project No. CMRPG370401).
EPIDEMIOLOGY AND HEALTH SERVICES RESEARCH
Incidence, cancer risk and mortality of dermatomyositis and polymyositis in Taiwan: a nationwide population study
Article first published online: 3 NOV 2011
© 2011 The Authors. BJD © 2011 British Association of Dermatologists 2011
British Journal of Dermatology
Volume 165, Issue 6, pages 1273–1279, December 2011
How to Cite
Kuo, C.-F., See, L.-C., Yu, K.-H., Chou, I.-J., Chang, H.-C., Chiou, M.-J. and Luo, S.-F. (2011), Incidence, cancer risk and mortality of dermatomyositis and polymyositis in Taiwan: a nationwide population study. British Journal of Dermatology, 165: 1273–1279. doi: 10.1111/j.1365-2133.2011.10595.x
Conflict of interest None declared.
- Issue published online: 24 NOV 2011
- Article first published online: 3 NOV 2011
- Accepted manuscript online: 6 SEP 2011 06:25AM EST
- Accepted for publication 21 August 11
Background Nationwide data on the epidemiology of dermatomyositis (DM) and polymyositis (PM) were limited.
Objectives This study was to estimate the incidence, occurrence of cancer and mortality of DM and PM in Taiwan.
Methods Both the register of critical illness of the Taiwan National Health Insurance Research Dataset and the National Death Registry of Taiwan were used to calculate estimates of the incidence, cancer association, and mortality of DM and PM between 2003 and 2007.
Results A total of 803 DM and 500 PM cases were identified between 2003 and 2007. Mean age at diagnosis was 44·0 ± 18·3 years for DM and 49·2 ± 15·9 years for PM. The overall annual incidences of DM and PM were 7·1 (95% CI 6·6–7·6) and 4·4 (95% CI 4·0–4·8) cases per million population. The incidence of both DM and PM increased with age and reached a peak at age 50–59 years. One hundred and eleven (13·8%) patients with DM and 31 (6·2%) patients with PM had cancers. The diagnosis of most cancers was made after the diagnoses of DM (n = 71; 64·0%) and PM (n = 21; 67·7%). Overall, the standardized incidence ratios (SIR) for cancer were 5·36 (4·12–6·87) and 1·80 (1·10–2·79) among patients with DM and PM; however, during the first year, SIRs for cancer were 24·55 (95% CI 18·62–31·79) and 9·17 (95% CI 14·82–15·93) in patients with DM and PM, respectively. The most common types of cancer were nasopharyngeal cancer for men and breast cancer for women. Patients with DM and PM had standardized mortality ratios of 7·68 (6·41–9·01) and 5·29 (4·28–6·48).
Conclusion This study reports robust estimates of important aspects of the epidemiology of both DM and PM in Taiwan. This highlights the rarity of these diseases, and their associated cancer risks and increased mortality.