Abstract: Background　Treatment-naive patients are not affected by medication，thus their clinical features can better reflect the changing rules of the disease，which is helpful to more accurate understanding of the occurrence and development of disease.However，there are few research reports about treatment-naive patients with systemic sclerosis（SSc）-associated thrombocytopenia.Objective　To analyze the clinical features and risk factors of treatment-naive SSc-associated thrombocytopenia.Methods　From 2013 to 2018，a total of 124 treatment-naive inpatients with SSc were selected from Department of Rheumatology and Immunology，the Affiliated Hospital of Southwest Medical University，and were divided into groups thrombocytopenia（n=12）and non-thrombocytopenia（n=112）according to the prevalence of SSc-associated thrombocytopenia.General information，clinical manifestations and laboratory examination results were compared between the two groups.Binary Logistic regression analysis was used to analyze the risk factors of SSc-associated thrombocytopenia.Results　The prevalence of SSc-associated thrombocytopenia was 9.7%（12/124）.There were no significant differences in gender ratio，average height and weight，distribution of types of SSc，prevalence of Raynaud's phenomenon，fingertip ulcer，arthromyositis and interstitial lung disease，average hemoglobin，WBC，albumin，TC，TG，Cr，BUN，and uric acid，and prevalence of antinuclear antibody，anti-SSA antibody，anti-SSB antibody，anti-Ro52 antibody，anti-SCL-70 antibody，anti PM-SCL antibody，anti JO-1 antibody as well as anti-CENP-B antibody positivity between the two groups（P>0.05）.Compared with those in non-thrombocytopenia group，thrombocytopenia group showed younger age，longer disease course，and lower BMI on average（P<0.05）.Besides，thrombocytopenia group demonstrated higher prevalence of pulmonary arterial hypertension（PAH），electrocardiographic abnormality and anti-RNP antibody positivity，lower average levels of complement C3 and C4（P<0.01）.Binary Logistic regression analysis results showed that，anti-RNP antibody positivity was the independent risk factor of SSc-associated thrombocytopenia〔OR=19.56，95%CI（2.04，187.87），P<0.01〕.Conclusion　Compared with those without thrombocytopenia，treatment-naive inpatients with SSc-associated thrombocytopenia showed younger age，longer disease course，lower BMI，complement C3 and C4，higher prevalence of PAH and electrocardiographic abnormality，and anti-RNP antibody positivity.Moreover，anti-RNP antibody positivity is the independent risk factor of SSc-associated thrombocytopenia.So clinicians should be vigilant of SSc-associated thrombocytopenia in treatment-naive SSc patients when they are found with anti-RNP antibody positivity after blood system damage is excluded.

Key words: Thrombocytopenia；Scleroderma, systemic；Disease attributes；Root cause analysis；Risk factors

摘要： 背景　初治患者不受药物治疗影响，其临床特征更能反映疾病本身变化规律，有助于更准确地了解疾病的发生、发展过程，但目前关于初治系统性硬化症（SSc）相关血小板减少症患者的研究报道较少见。目的　分析初治SSc相关血小板减少症患者的临床特征及其危险因素。方法　选取2013—2018年西南医科大学附属医院风湿免疫科住院部收治的初治SSc患者124例，根据SSc相关血小板减少症发生情况分为血小板减少症组12例和非血小板减少症组112例。比较两组患者一般资料、临床表现、实验室检查指标；初治SSc患者SSc相关血小板减少症的危险因素分析采用二元Logistic回归分析。结果　本研究初治SSc患者SSc相关血小板减少症发生率为9.7%（12/124）。两组患者性别、身高、体质量比较，差异无统计学意义（P>0.05）；血小板减少症组患者年龄小于非血小板减少症组，病程长于非血小板减少症组，体质指数（BMI）低于非血小板减少症组（P<0.05）。两组患者SSc类型及雷诺现象、指尖溃疡、关节肌肉炎、肺间质病变发生率比较，差异无统计学意义（P>0.05）；血小板减少症组患者肺动脉高压发生率高于非血小板减少症组（P<0.01）。血小板减少症组患者补体C3、补体C4低于非血小板减少症组，心电图异常发生率及抗核糖核蛋白抗体（nRNP）阳性率高于非血小板减少症组（P<0.01）；两组患者血红蛋白、白细胞计数、白蛋白、总胆固醇、三酰甘油、肌酐、尿素氮、尿酸及抗核抗体、抗SSA抗体、抗SSB抗体、抗Ro-52抗体、抗SCL-70抗体、抗PM-SCL抗体、抗JO-1抗体、抗着丝点抗体B阳性率比较，差异无统计学意义（P>0.05）。二元Logistic回归分析结果显示，nRNP阳性是初治SSc患者SSc相关血小板减少症的独立危险因素〔OR=19.56，95%CI（2.04，187.87），P<0.01〕。结论　与单纯初治SSc患者相比，初治SSc相关血小板减少症患者年龄较小，病程较长，BMI、补体C3、补体C4较低，PAH发生率、心电图异常发生率及nRNP阳性率较高，且nRNP阳性是初治SSc患者SSc相关血小板减少症的独立危险因素，当初治SSc患者进行自身抗体谱检测发现nRNP阳性时应警惕SSc相关血小板减少症的发生，并注意排除血液系统损伤等。

关键词: 血小板减少；硬皮病, 系统性；疾病特征；影响因素分析；危险因素