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Prognostic markers in patients with antineutrophil cytoplasmic autoantibody-associated microscopic polyangiitis and
S L Hogan1, P H Nachman, A S Wilkman
1Department of Medicine, University of North Carolina at Chapel Hill 27599-7155, USA.
Abstract:
The purpose of this study was to determine the prognostic value of clinical, laboratory, and pathologic features at the time of presentation on patient and renal survival in patients with antineutrophil cytoplasmic autoantibody (ANCA)-associated microscopic polyangiitis and glomerulonephritis (excluding Wegener's granulomatosis). One hundred seven ANCA-positive patients with necrotizing and crescentic glomerulonephritis, including 69 with evidence for microscopic polyangiitis, were evaluated for this study. The relative risk of death was calculated for the following potential prognostic indicators: (1) ANCA pattern; (2) pulmonary hemorrhage at onset; (3) presence of extrarenal manifestations versus renal limited disease; and (4) treatment with corticosteroids and cyclophosphamide (intravenous or oral), compared with corticosteroids alone. Cox's proportional hazard model was used to assess the predictive value of the following variables on renal survival: (1) age; (2) race; (3) pulmonary symptoms at onset of disease; (4) renal pathology; (5) ANCA pattern; and (6) peak serum creatinine values obtained near the time of renal biopsy. Patients were followed prospectively for 2.5 yr (range, 5 days to 12 yr 2 months). There were 12 disease-related deaths and 46 patients who reached ESRD. The relative risk (and 95% confidence interval) of patient death was 8.65 (3.36, 22.2) times greater in patients who presented with pulmonary hemorrhage, and 3.78 (1.22, 11.70) times greater in patients with cytoplasmic ANCA compared to those with perinuclear ANCA. The relative risk of pulmonary hemorrhage was no different by ANCA pattern. The risk of death was 5.56 times lower in the cyclophosphamide-treated patients versus those treated with corticosteroids alone. The predictors of renal survival were entry serum creatinine value (P = 0.0002), race (African Americans having a worse outcome compared with Caucasians, P = 0.0008), and the presence of arterial sclerosis on kidney biopsy (P = 0.0076) when controlling for age, ANCA pattern, microscopic polyangiitis versus glomerulonephritis alone, and pulmonary involvement. Pathology indices such as glomerular necrosis, glomerular crescents, glomerular sclerosis, and interstitial sclerosis were not predictive of renal survival when controlling for entry serum creatinine value, race, and arterial sclerosis. However, in the subgroup of patients with a peak creatinine value of < or = 3.0 mg/dL (N = 29), increased interstitial sclerosis was a predictor of a poor renal outcome (P = 0.04).
Insights
Pulmonary hemorrhage and cytoplasmic ANCA patterns at presentation significantly increase mortality risk in ANCA-associated vasculitis. Cyclophosphamide treatment and lower initial creatinine levels improve patient and renal survival, respectively.
Area of Science:
- Nephrology
- Rheumatology
- Immunology
Background:
- Antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis, including microscopic polyangiitis and glomerulonephritis, presents with diverse clinical, laboratory, and pathological features.
- Predicting patient and renal survival in these conditions is crucial for effective management.
Purpose of the Study:
- To evaluate the prognostic significance of clinical, laboratory, and pathological findings at presentation for patient and renal survival in ANCA-associated microscopic polyangiitis and glomerulonephritis.
Main Methods:
- A cohort of 107 ANCA-positive patients with necrotizing and crescentic glomerulonephritis was analyzed.
- Cox's proportional hazard models assessed the relative risk of death and predictors of renal survival, considering factors like ANCA pattern, pulmonary hemorrhage, extrarenal manifestations, treatment regimens, age, race, and renal pathology.
Main Results:
- Patients presenting with pulmonary hemorrhage had a 8.65-fold higher risk of death. Cytoplasmic ANCA patterns were associated with a 3.78-fold increased risk of death compared to perinuclear patterns.
- Cyclophosphamide treatment reduced the risk of death by 5.56-fold compared to corticosteroids alone.
- Predictors of renal survival included lower entry serum creatinine, Caucasian race, and absence of arterial sclerosis on kidney biopsy. Interstitial sclerosis predicted poor renal outcome in patients with peak creatinine ≤ 3.0 mg/dL.
Conclusions:
- Clinical presentation (pulmonary hemorrhage) and ANCA pattern are significant predictors of mortality in ANCA-associated vasculitis.
- Treatment with cyclophosphamide improves survival, while initial creatinine, race, and arterial sclerosis are key determinants of renal survival.