FP155PREDICTORS OF RENAL INVOLVEMENT IN ANCA ASSOCIATED VASCULITIS

Abstract

Introduction and Aims: Renal involvement inanti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis remains a predictor of higher morbidity and mortality. The aim of the current study was to investigate potential predictors of kidney involvement in patients with underlying ANCA-associated vasculitis. For this purpose, we used patients recruited into the international Diagnostic and Classification Criteria in Vasculitis (DCVAS) study. Methods: DCVAS is an international observational study to develop new classification criteria for ANCA-associated vasculitis. The retrieved dataset compromises data on clinical manifestations and laboratory findings of patients. Statistical comparisons were made by using the Student's t-test and chi-square-test for univariate analysis. All significant variables were entered into the multivariate model. Stepwise logistic regression analysis was used for multivariate analysis. All differences were considered significant at p < 0.05. Results: Among the 1230 patients, 723 presented with renal involvement (58.78%). Most patients with renal vasculitis had microscopic polyangiitis (267 out of 325, 82.15%), followed by granulomatosis with polyangiitis (395 out of 674 patients, 58.6%) and eosinophilic granulomatosis with polyangiitis (61 out of 231, 26.41%). Figure 1 shows a detailed overview over patients' geographical origin. Median peak erythrocyte sedimentation rate (ESR) in the first hour (55.43 versus 48.58 mm), peak C-reactive protein (68.73 versus 53.77 mg/l), serum creatinine (136.35 versus 81.23 mol/l) as well as creatinine clearance as assessed by the MDRD formula (73.64 versus 87.12 ml/min) and the CKD-EPI formula (76.10 versus 90.04 ml/min) were significantly different in those with renal involvement. Preliminary mulitvariate analysis revealed that weight loss (OR 1.535, 95% CI 1.058-2.228, p=0.024), bloody-stained broncho-alveolar lavage (OR 2.768, 95% CI 1.151-6.656, p=0.023), peritonism (OR 47.537, 95% CI 1.252-1804.867, p=0.037), microscopic hematuria (OR 2.400, 95% CI 1.627-3.539, p<0.001) and polyarthritis (OR 1.877, 95% CI 1.050-3.356, p=0.034) were predictors of kidney involvement, whereas respiratory distress, pulmonary fibro-sis or asthma (OR 0.581, 95% CI 0.365-0.926, p=0.022) were not. Conclusions: Among patients with ANCA-associated renal vasculitis, we found an elevated ESR as well as higher CRP and serum-creatinine in baseline. Creatinine clearance was lower in those with renal involvement at baseline. Preliminary analyses indicated an association with weight loss, bloody-stained broncho-alveolar lavage, peri-tonism, microscopic hematuria and polyarthritis at baseline. Further large studies are needed to corroborate the findings observed in the DCVAS cohort.