AB0627 PROGNOSIS AND MORTALITY OF DERMATOMYOSITIS AND POLYMYOSITIS PATIENTS WITH MALIGNANCY
Authors: X. Yang, Y. Hao, Z. Zhang
Journal: Annals of the Rheumatic Diseases (2020)

Background: Previous studies indicate that cancers in DM/PM patients are associated with increased mortality. Hence, identifying predictors of malignancy in PM and DM is crucial. However, few large series studies have reported prognostic and predictive factors of malignancy in patients with PM and DM. Moreover, in recent years, several published studies also allow us to better understand the clinical characteristics of malignancy in PM and in DM. Objectives: To analyze the mortality and identify the major independent risk factors for death in patients with dermatomyositis/polymyositis (DM/PM) complicated with malignant tumor. Methods: The clinical data of all patients with DM/PM in Peking University First Hospital from January 2007 to Jan 2019 were retrospectively reviewed. All patients were followed up to confirm whether they had malignant tumors. According to the statistics of the National Bureau of Statistics of China, the standard mortality (SMR) and life lost years (YLL) of patients with DM/PM were combined with malignant tumors. The Kaplan-Meier method was used to analyze the 10-year survival of DM/PM patients with malignant tumors. Cox multivariate regression was used to predict independent risk factors for DM/PM patients with malignant tumors. Results: A total of 334 patients with dermatomyositis and 69 patients with polymyositis were enrolled in the study. The mean age of onset was 50.5 ± 14.8 years and 48.9 ± 16.1 years, with a median follow-up of 40.6 (11.6-77.6) months. Among them, 320 patients were successfully followed up, including 69 patients with death, 46 DM/PM with malignant tumors (38 with dermatomyositis and 8 with polymyositis). The average age of onset of DM/PM patients with malignant tumors was 55.4 ± 15.1 years and 59.5 ± 4.7 years, respectively, of which 17 died. The age-sex adjusted SMR of DM/PM patients without malignant tumors was 9.0 (95% CI 6.8-11.2). The age-sex adjusted SMR of DM/PM with malignant tumors was 12.3 (95% CI 9.0-14.7). The life loss of male patients with dermatomyositis complicated with malignant tumors was 30.1 years, and that of females was 38.6 years; the life loss of male patients with polymyositis was 27.6 years, and that of females was 22.1 years. A 10-year survival analysis showed that DM/PM patients with malignant tumor had significantly worse prognosis than patients without malignancy (p=0.001 Log-rank). The 1-, 5-, and 10-year survival rates of DM/PM patients who did not have malignant tumors were 87.9%, 81.9%, and 78.4%, respectively. DM/PM Patients with malignant tumors 1, 5, and 10 years The survival rates were 73.3%, 56.0%, and 45.7%, respectively. The independent risk factors for death in DM/PM patients with malignant tumors were advanced age (HR=1.11 95% CI 1.02-1.20, p=0.014) and infection (HR=17.07 95% CI 1.66-175.75, p= 0.017). Conclusion: Malignant tumor is a common in patients with DM/PM, and the mortality of DM/PM patients with malignant tumors is high. The independent predictors of mortality for PM/DM patients with malignant tumors were age at disease onset and infection. Acknowledgments: We thank our patients with PM/DM participating in this study. Disclosure of Interests: None declared