PT  - JOURNAL ARTICLE
AU  - Min Wook So
AU  - Bon San Koo
AU  - Yong-Gil Kim
AU  - Chang-Keun Lee
AU  - Bin Yoo
TI  - Idiopathic Inflammatory Myopathy Associated with Malignancy: A Retrospective Cohort of 151 Korean Patients with Dermatomyositis and Polymyositis
AID  - 10.3899/jrheum.110320
DP  - 2011 Aug 15
TA  - The Journal of Rheumatology
PG  - jrheum.110320
4099  - http://www.jrheum.org/content/early/2011/08/10/jrheum.110320.short
4100  - http://www.jrheum.org/content/early/2011/08/10/jrheum.110320.full
AB  - Objective To define the standardized incidence ratio (SIR) of malignancy and factors associated with malignancies in Korean patients with dermatomyositis (DM) and polymyositis (PM). Methods The demographic, clinical, and laboratory features of 151 patients diagnosed with DM/PM were compared in patients with and without malignancies. Results Malignancies were found in 23 of 98 patients with DM (23.5%) and in 2 of 53 with PM (3.8%). Lung cancer (8 patients) was the most common malignancy. Compared with the period-specific, sex-matched, and age-matched Korean population, the SIR for malignancy in patients with DM was 14.2 (95% CI 9.0–21.3). Univariate analysis showed that factors associated with malignancy included older age (p < 0.001), DM (p = 0.002), dysphagia (p < 0.001), the absence of interstitial lung disease (ILD; p = 0.001), and lower elevations in aspartate aminotransferase (p = 0.005) and lactate dehydrogenase concentrations (p < 0.001). Multivariate analysis showed that factors independently associated with malignancy included older age (per 10 years, OR 2.3, 95% CI 1.6–3.5, p < 0.001), DM (OR 5.9, 95% CI 1.3–26.2, p = 0.020), dysphagia (OR 2.6, 95% CI 1.2–6.6, p = 0.042), and the absence of ILD (OR 0.1, 95% CI 0.01–0.9, p = 0.040). Conclusion DM was associated with a greater risk of concomitant malignancies, especially lung cancer, than PM. Independent factors associated with malignancies in patients with DM/PM were older age, the presence of dysphagia, and the absence of ILD.