肌炎特异性自身抗体对多发性肌炎/皮肌炎患者预后影响

The impact of myositis-specific autoantibodies on the survival of patients with polymyositis and dermatomyositis

目的分析不同肌炎特异性自身抗体（MSAs）对PM和DM患者预后的影响。方法通过随访中日友好医院风湿科1994—2015年住院的PM/DM患者，分析不同MSA的PM/DM患者的Kaplan-Meier生存曲线，并用多因素Cox回归模型分析影响PM/DM患者预后的因素。结果共383名PM/DM患者随访1~333个月，所有PM/DM患者累计生存率和10年生存率分别为68.6%和76.2%。其中MSAs阳性患者3年和5年的生存率为80.4%和77.1%，低于MSAs抗体阴性患者3年和5年的生存率（分别为90.1%和87.4%）（χ2=3.90和3.98，P〈0.05）。各MSAs组长期预后差异有统计学意义（χ2=40.654，P〈0.01），其中抗黑色素分化相关基因5（MDA5）抗体阳性的PM/DM患者预后最差，10年生存率仅28.7%，而抗3-羟基-3-甲基-辅酶A还原酶蛋白（HMGCR）抗体阳性者预后最好，10年生存率为100%。多因素分析显示影响PM/DM患者生存的独立危险因素包括发病年龄、合并肿瘤、吞咽困难、合并快速进展性间质性肺病、抗MDA5抗体阳性、血清AST和CRP升高等。结论不同MSAs对PM/DM患者的生存期有影响，MSA阳性者5年内的生存率更低，提示早期筛查MSAs并积极治疗可能改善患者的预后。

Objective To investigate the association of distinct myositis specific autoantibodies （MSAs） with long-term survival of patients with polymyositis （PM） and dermatomyositis （DM）.Methods We analyzed the clinical data and outcome of patients with PM and DM who were hospitalized in the department of rheumatology of China-Japan Friendship hospital from 1994 to 2015, and evaluated the impact of MSAs on the prognosis of patients. Multivariate Cox regression analysis was used to identify the prognostic risk factors for PM/DM patients.Results A total of 383 PM/DM patients were followed up for 1-333 months. Cumulative survival and 10-year survival rate of all patients were 68.6% and 76.2%, respectively. The survival rate of 80.4% and 77.1% at 3 and 5 years in patients with MSAs, which were lower than those of patients with-out MSAs, who had the survival rate of 90.1% and 87.4% at 3 and 5 years, respectively（χ2=3.90 and 3.98, P〈0.05）. There was significant difference for long-term survival in all MSAs positive groups （χ2=40.654, P=0.000）. Anti-MDA5 positive patients who had the 10-year survival rate of 28.7% had the worst prognosis, while anti-HMGCR positive patients who had the 10-year survival rate of 100% had the best outcome in all groups. Multivariate Cox regression analysis showed that independent risk factors associated with the long-term survival of patients were age of onset, complicated with malignancies, dysphagia, rapidly progress interstitial lung disease, anti-MDA5 antibody positive, increased serum aspartate transferase and C reaction protein.Conclusion MSAs are strongly associated with the prognosis of patients with PM/DM. Patients with MSAs has worse 5-year overall survival than those without MSAs, which indicates that screening MSAs and aggressive treatment for PM/DM patients at very early stage of disease may improve the outcome.