Clinical Characteristics And Prognosis Of ANCA-associated Vasculitis With Thrombocytopenia

ObjectiveTo investigate the clinical characteristics and prognosis of antineutrophil cytoplasmic antibody-associated vasculitis with thrombocytopenia,so as to improve the understanding of this clinical complication.MethodWe retrospectively reviewed the clinical data of 16 AAV patients with thrombocytopenia in the First Affliated Hospital of Zhengzhou University from January 2013 to September 2019,and compared with 80 AAV patients without thrombocytopenia.The clinical characteristics between the two groups were statistically analyzed.Quantitative data that were normally distributed were expressed as x±s and compared by t test,if not,expressed as the median(P25,P75)and compared by Mann-Whitney test.Qualitative data were described by frequency(percentage)and compared.by Chi-squared test or Fisher's exact probability test.Kaplan-Meier curves were plotted to determine the survival time and survival outcome between the two groups.Finally,the Univariate regression analysis and multivariate regression analysis to explore the risk factors of poor prognosis of AAV.Result1.The positive rate of hemoptysis/alveolar hemorrhage,pleural effusion/pleurisy,peritoneal effusion,nervous system involvement,positive rate of c-ANCA and PR3-ANC A in the thrombocytopenia group were higher than those in the normal platelet group(P<0.05).In the thrombocytopenia group,C-reactive protein was higher than that in the normal platelet group,while RBC,Hb,albumin and C3 were significantly lower than those in the normal platelet group(P<0.05).Spearman correlation analysis showed that there was a correlation between platelet count and complement C3(rs=0.222,P=0.044).2.Survival analysis showed that the survival rate of the thrombocytopenia groups decreased(?2=20.326,P<0.001),and the mean survival time decreased(31.66 months vs 64.31 months,P<0.001).HR=8.085(95%CI 2.771-23.595,P<0.001).3.Univariate regression analysis showed that hemoptysis/alveolar hemorrhage(OR 6.9,95%CI 1.485-32.070,P=0.014),nervous system involvement(OR 9.682,95%CI 1.45-64.639,P=0.019),thrombocytopenia(OR 14.889,95%CI 3.866-57.337,P<0.001),albumin reduction(OR 14.114,95%CI 1.754-113.559,P=0.013),and c-ANCA(OR 10.2,95%CI 2.529-41.145,P=0.001)were risk factors for poor prognosis of AAV.Multivariate regression analysis found that only thrombocytopenia was an independent risk factor for poor prognosis of AAV(OR 6.175,95%CI 1.342-28.407,P=0.019).Conclusion1.There is a higher probability of alveolar hemorrhage in the AAV with thrombocytopenia than the normal group.In severe cases,they may have respiratory failure.In addition,they are prone to multiple serous cavity effusion,gastrointestinal tract and central nervous system involvement,increase of C-reactive protein,decrease of hemoglobin,decrease of albumin and decrease of complement C3.2.AAV patients with thrombocytopenia have a poor prognosis and high mortality.Thrombocytopenia is an independent risk factor for poor prognosis of AAV.