Long-term follow-up of microscopic polyangiitis, 17-year experience at a single center.

Abstract

BACKGROUND: Long-term prognoses of Wegener granulomatosis (WG) and Churg-Strauss syndrome (CSS) are known; however, few data exist on long-term prognoses for microscopic polyangiitis (MPA). Our aim was to analyse the prognoses of MPA. METHODS: Cohort study with retrospective selection of patients. Twenty-two patients admitted to our Hospital (1990-2006) with biopsy-proven MPA were studied. The start date for entry into the study was the date of diagnosis. Statistical analysis was performed to look for prognostic factors for survival. RESULTS: MPA patients were followed-up for a median of 78 (5-131) months. MPA patients were treated with cyclophosphamide (Cy) plus corticosteroid (Cs) (59%) or Cs alone (41%). Seven MPA patients died. Cumulative MPA patient survival at 1, 5, and 10 years were 85% (75-95%), 85% (75-95%), and 74% (60-88%) in those treated with Cy plus Cs and 50% (32-68%), 36% (14-58%), and 0% (0-30%) in those treated with Cs alone, respectively (P=0.04). Disease extent index <5 (P=0.02) and age <65 years (P=0.02) were associated with improved survival rates in MPA patients treated with Cy. Five MPA (23%) patients relapsed after a median of 54 months (35-93). No variables were related to relapses. Despite treatment, 11MPA (50%) patients developed end-stage renal disease after a median of 9 months (0-53). CONCLUSIONS: Most MPA patients had life-threatening renal or lung involvement at diagnosis. Patients not treated with immunosuppressants had a poorer prognosis. The long-term prognosis of MPA patients who survived 6 months post diagnosis was good, although renal survival rates are low.