Background/Purpose: The proportion of patients who experience new manifestations of vasculitis after diagnosis is unknown.  Our objectives were to quantify the occurrence of new features of vasculitis after diagnosis in 6 types of vasculitis and to compare patterns of disease activity over time.

   Methods: Standardized data collection on 98 disease manifestations in 6 vasculitides, including granulomatosis with polyangiitis (Wegener’s, GPA), microscopic polyangiitis (MPA), Churg-Strauss syndrome (CSS), polyarteritis nodosa (PAN), giant cell arteritis (GCA), and Takayasu’s arteritis (TAK), was performed within a set of multicenter, longitudinal cohorts.  For each form of vasculitis, the frequency of disease-specific manifestations at diagnosis was compared to the cumulative frequency of each manifestation.  The percentage of patients who developed new “severe” manifestations after diagnosis, defined as organ-threatening or life-threatening in the small and medium vessel vasculitides and as ischemic/vascular in the large vessel vasculitides, was described. 

   Results: The number of patients and median length of follow-up (years) for the vasculitides was: GPA 341, 7.2; MPA 26, 3.7; CSS 117, 5.1; PAN 55, 4.3; GCA 191, 2.8; TAK 132, 6.8.  On average, patients with vasculitis experienced 1.3 new disease manifestations after diagnosis (GPA – 1.9, MPA – 1.2, CSS – 1.5, PAN – 1.2, GCA – 0.7, TAK – 1.0).  Depending on the type of vasculitis, at least 1 new disease manifestation occurred after diagnosis in 44%-69% of patients (Figure), most notably in GPA and CSS.  A subset of patients (7-28%) with each type of vasculitis experienced ≥ 3 new manifestations after diagnosis.  The 3 most frequent new manifestations after diagnosis for each type of vasculitis are listed in the Table.  New severe manifestations occurred after diagnosis in GPA – 30%, MPA – 27%, CSS – 23%, PAN – 29%, GCA – 26%, and TAK – 45%.  Mean time from diagnosis to initial flare in disease activity did not significantly differ among those who experienced a new manifestation versus a recurrence of prior disease (1.15 vs 1.18 years, p=0.8).

   Conclusion: A majority of patients with vasculitis develop new features of disease after diagnosis, including a substantial number of new, severe manifestations.  New manifestations after diagnosis, although more frequent among the small-vessel vasculitides, are also common in patients with medium- or large-vessel vasculitis.  Patterns of disease recurrence after diagnosis are not related to disease duration.  Ongoing clinical assessment of patients with all types of established vasculitis should remain broad in scope.