ANCA positive crescentic glomerulonephritis outcome in a Central East European cohort: a retrospective study

BACKGROUND: The recently suggested distinct pathogenic pathways for myeloperoxidase (MPO) and proteinase 3 (PR3) anti-neutrophilic cytoplasmic antibodies (ANCA) associated vasculitis could result in different modes of presentation and outcome. Moreover, kidney outcome was related to a new histopathologic classification of pauci-immune glomerulonephritis. As reports were not always concordant, possible because differences in severity of organ lesions and ethnicity, we evaluated the outcome of a cohort of Central-East European patients with crescentic glomerulonephritis in relation with ANCA specificity and histopathological classification. METHODS: Seventy-five patients were consecutively diagnosed by kidney biopsy (76 % MPO-ANCA specificity, 52 % crescentic) and followed for a median period of 3.2 years. Study end-points were response to therapy, end stage renal disease (ESRD) and death. RESULTS: PR3-ANCA patients were younger, in higher proportion male and had higher Birmingham Vasculitis Activity Scores (BVAS). The kidney disease was severe at presentation (median creatinine 5 mg/dL; 27 % required temporary dialysis) and worst in PR3-ANCA positive patients (50 % patients needed temporary dialysis vs. 19 %). The lung was the second most affected organ (31 % severe lung hemorrhage). Lung and kidney damage were related; the odds of hemorrhagic alveolitis in patients needing dialysis at presentation were 4 (95 % CI 1–13; p = 0.006) times higher than in those who did not. The rate of response to therapy (without signs of active vasculitis and stable or declining serum creatinine) was 60 % and was associated with dialysis independency, older age and higher platelet number at presentation. The probabilities to survival 1 and 5 years for kidney and patient were 93 and 64 %, and respectively 88 and 67 %. Kidney survival was predicted by response to therapy and dialysis independency at presentation. Patients with BVAS < 15 and responding to induction therapy had better chances of survival. Neither response to therapy nor outcome was influenced by ANCA specificity or by the histopathological class. CONCLUSIONS: When kidney damage is severe in ANCA vasculitis, the need of dialysis at presentation and the response to induction therapy overcome the prognostic utility of both ANCA specificity and histopathological class.