Doubled prevalence rates of ANCA-associated vasculitides and giant cell arteritis between 1994 and 2006 in northern Germany

Objectives. The aim of this study was to investigate the period prevalences of ANCA-associated vasculitides (AAV), including granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), eosinophilic GPA (EGPA)/Churg-Strauss and GCA, in an urban and rural population in northern Germany in 2006 and to compare the data with our previous study performed in 1994. Methods. We identified of all patients with AAV or GCA via questionnaires to all hospital departments, physicians, health insurance providers, pension funds, reference laboratories for autoimmune diseases and death registries in Luebeck (city) and the rural region of Segeberg (population 468 962) between January and December 2006. The type of vasculitis, gender, year of birth, postal code and death were documented and re-evaluated. Results. One-hundred and fifty patients were identified, indicating a prevalence of 320 per million inhabitants for the complete catchment area (95% CI 285, 355). GCA was more prevalent than AAV: 171 (146, 197) vs 149 (126, 174). GCA and AAV have almost doubled since 1994. GCA increased from 240 (164, 315) to 440 (399, 481) per million in the population epsilon 50 years of age and AAV increased from 74 to 149 cases per million. GCA and AAV were more prevalent in the urban compared with the rural region. Conclusion. The prevalence rates of AAV and GCA almost doubled from 1994 to 2006 for this region with a stable population and using an identical study design. Increased awareness has led to an earlier diagnosis of systemic vasculitis and improved activity-adapted treatment mostly based on randomized controlled trials has led to longer survival. Aspects such as environmental factors and exposure to certain substances need further research.