Outcome and prognostic factors during the course of primary small-vessel vasculitides

Objective. To identify the prognostic factors of relapse and/or death during the course of primary small-vessel vasculitides (PSVV), and to differentiate their prognostic relevance by the type of vasculitis. Methods. Seventy-five patients were retrospectively followed up after diagnosis: 36 with Wegener's granulomatosis (WG), 23 with Churg-Strauss syndrome (CSS), and 16 with microscopic polyangiitis. Cox regression analysis was used to identify the significant predictors of relapse and death. Results. Gastrointestinal (G1) involvement was associated with an increased risk of relapse, mainly in the patients with CSS, whereas renal disease and perinuclear antineutrophil cytoplasmic antibody positivity were correlated with a lower risk of relapse. Presence of nasal Staphylococcus aureus tended to increase the risk of relapse in CSS [hazard ratio (HR) 4.45, p = 0.087], but to decrease it in WG (HR 0.12, p = 0.066). Older age, renal and hepatic involvement, erythrocyte sedimentation rate ≥ 100 mm/h, and serum creatinine level > 1.5 mg/dl were all related to higher risk of death in univariate analysis; however, only cerebral (HR 8.52, p = 0.021) and hepatic involvement (HR 4.40, p = 0.028) and serum creatinine level ≥ 1.5 mg/dl (HR 5.72, p = 0.044) were independently correlated with an unfavorable prognosis for survival. The risk of death associated with each of these indicators did not depend on the form of PSVV. Conclusion. G1 involvement increases the risk of relapse in CSS, whereas the prognostic significance of nasal S. aureus in terms of relapse seems to be opposite in patients with CSS and those with WG. Patients with cerebral, hepatic, and renal involvement have the poorest prognosis for survival. Our data do not show that the prognostic relevance of these factors depends on the form of PSVV.