Clinical Features And Prognosis Of Pulmonary Involvement In ANCA-Associated Vasculitis

Objective:This study was to describe the clinical features of pulmonary involvement in ANCA-associated vasculitis(AAV)and to identify possible prognostic factors of AAV patients with pulmonary involvement to improve the clinical management and the prognosis of such patients.Methods:A prospective cohort study of AAV was conducted based on data acquired by the Chinese Rheumatism Data Center(CRDC).The cohort involved 150 patients diagnosed with AAV in the Second Affiliated Hospital of Nanchang University Hospital from January 2013 to July 2022.Baseline and follow-up data were prospectively collected.According to the presence or absence of lung involvement,150 patients were divided into lung involvement group and non-lung involvement group.The differences in clinical features,laboratory tests and survival time between the two groups were compared.Based on baseline high resolution pulmonary computed tomography(HRCT),the lung involvement group were evaluated and re-classified into four subgroups:alveolar hemorrhage(AH),interstitial lung disease(ILD),pulmonary granuloma(PG),and airway involvement(AI).The differences in clinical features and laboratory tests among the groups were compared,and the survival differences among the groups were analyzed by Kaplan-Meier survival curve.Univariate and multivariate Logistic and Cox regression analyses were used to investigate the risk factors associated with prognosis in patients with AAV lung involvement.Results:1.A total of 150 patients were enrolled in total,including 77 males(51.3%)and73 females(48.7%),with a male-female ratio of about 1:1.The mean ae at onset was(57.8±15.5)years old,and the majority of patients between 55 and 74 years old,accounting for 48.0%.Among the AAV cases,kidney involvement(74.0%)and pulmonary involvement(58.0%)were most common.2.The course of disease in the non-pulmonary involvement group was longer than that in the pulmonary involvement group(Z=-2.117,P=0.034),and the follow-up time in the non-pulmonary involvement group was longer than that in the pulmonary involvement group(Z=-3.623,P<0.001).The proportion of patients with elevated serum creatinine in the pulmonary involvement group was higher than that in the non-pulmonary involvement group(χ2=5.429,P=0.020).The erythrocyte sedimentation rate was lower in the pulmonary involvement group than in the non-pulmonary involvement group(Z=-2.189,P=0.029).The proportion of plasma exchange in the pulmonary involvement group was higher than that in the non-pulmonary involvement group(χ2=4.585,P=0.032).3.The mean survival time of lung involvement AAV patients was(57.0±4.1)months,and that of non-lung involvement AAV patients was(96.9±3.0)months.The difference was statistically significant(P=0.018).4.The age of onset in the ILD group was older than that in the PG group(H=12.295,P=0.020).The proportion of diabetes and hyperlipidemia in the PG group was higher than that in the ILD group(χ~2=12.172,P=0.003).There was a significant difference in the proportion of AAV diagnostic types among the four groups(χ~2=42.630,P<0.001).AH and ILD were more common in MPA,and PG was more common in GPA.At baseline,the incidences of hematuria,proteinuria,elevated serum creatinine,serum creatinine level,blood urea nitrogen level,BVAS score and five factor score in the AH group were higher than those in the other groups(P<0.05).The incidence of overall renal involvement in the AH group was higher than that in the AI group(χ~2=10.109,P=0.030).At baseline,the hemoglobin level,platelet level,and glomerular filtration rate in the AH group were significantly lower than those in the other groups(P<0.005).At baseline,the proportion of glucocorticoid pulse,plasma exchange and hemodialysis in the AH group was higher than that in the other groups(P<0.05),and the proportion of mycophenolate mofetil use in the PG group was higher than that in the AI group(χ~2=11.223,P=0.011).Lung involvement AAV patients with different imaging features had different prognosis,and the prognosis of AH group and ILD group was worse(P=0.038).5.The remission rate in this study was 75.9%,and the relapse rate was 16.9%,the mortality rate was 14.5%,and the infection rate was 56.6%.Smoking history(HR=5.800,95%CI:1.719-19.569,P=0.005),low baseline hemoglobin level(HR=1.035,95%CI:1.007-1.063,P=0.014)and weight loss(HR=12.758,95%CI:3.012-54.040,P=0.001)were independent risk factors for recurrence in AAV patients with pulmonary involvement.Advanced age of onset(HR=1.025,95%CI:1.002-1.101,P=0.048),longer disease duration(HR=1.115,9 5%CI:1.005-1.218,P=0.043),and concurrent malignant tumor(HR=8.600,95%CI:1.462-50.599,P=0.017),and respiratory failure(HR=13.274,95%CI:1.846-95.461,P=0.010)were independent risk factors for mortality in AAV patients with pulmonary involvement,and were negatively correlated.Smoking history(OR=3.957,95%CI:1.247-12.553,P=0.020)and BVAS score≧20(OR=4.129,95%CI:1.019-16.729,P=0.047)were independent risk factors for AAV patients with pulmonary involvement.Conclusion:Pulmonary involvement affects prognosis in patients with ANCA-associated vasculitis and the prognosis of AH and ILD patients with lung involvement was poor.Smoking history,low baseline hemoglobin level and weight loss were independent risk factors for recurrence in AAV patients with pulmonary involvement.Advanced age,long course of disease,concurrent malignant tumor and respiratory failure were independent risk factors for mortality in patients with AAV lung involvement.Smoking history and BVAS score≧20 were independent risk factors for AAV patients with pulmonary involvement.Therefore,in order to improve the prognoses of patients with AAV lung involvement,we should identify these risk factors of the prognosis early,assess the condition and develop appropriate treatment options.