Objective: To register all newly diagnosed patients with primary systemic vasculitis (PSV) in two large regions in north and south Germany.
Methods: Between 1 January 1998 and 31 December 1999, all newly diagnosed cases of PSV, as defined by the Chapel Hill Consensus Conference 1992, were identified in two large mixed rural/urban regions in north and south Germany with a combined population of 4,880,543, for a population-based prospective study. The following sources were used: (i) all departments of every hospital, including their out-patient clinics; (ii) all departments of pathology; and (iii) all reference immunological laboratories serving the catchment area. All cases were re-evaluated by the authors.
Results: Over the whole period, 473 individuals were registered as having a new PSV. The incidence rates for all PSV were 54 cases per 1,000,000 inhabitants in the north and 48 in the south in 1998, and 48 and 41 respectively in 1999. People 50 yr and older had a three- to five-fold higher risk of getting PSVs than those under 50 yr. The incidences of antineutrophil cytoplasmic antibody (ANCA)-associated PSVs [Wegener's granulomatosis (WG), microscopic polyangiitis (MPA) and Churg-Strauss syndrome (CSS)] remained stable in both regions, at about 9.5 per 1,000,000 annually. The incidence of WG was two to three times greater than those of MPA and CSS. There was no difference in incidence rates between north and south Germany.
Conclusion: First results from a population-based vasculitis register serving nearly 5,000,000 inhabitants in north and south Germany revealed no regional differences in the incidence of all PSVs between north and south. The incidence rates of ANCA-associated PSVs, such as WG and MPA, were lower than those in the UK and Norway but higher than that in Spain.