Background: The frequency of primary systemic small vessel vasculitides (PSV) varies among different geographic regions and age categories. We studied PSV in patients from middle-eastern Crete (Greece), and compared clinical characteristics in younger (<65 years) versus older (> or = 65 years) adult patients.
Methods: The records of 67 patients (33 younger, 34 older adults) diagnosed with PSV during 1995-2003 who were referred to a mixed secondary/tertiary care University Hospital in Crete were reviewed. Data on clinical manifestations, diagnosis, therapy, and adverse outcomes (end stage renal disease, death) during a median follow-up of 6 (range 0-12) years were recorded. Multivariate regression analysis was applied to identify independent predictors for adverse outcomes.
Results: The overall annual incidence of PSV was 19.5/million (95% confidence interval [CI] 15.7-23.4), 48.9/million (95% CI 33.8-63.9) in older and 12.4/million (95% CI 7.7-17) in younger adults. Microscopic polyangiitis was more prevalent in older patients (65%) and Wegener's Granulomatosis in younger patients (52%). Thirty-one percent of older patients developed end-stage renal disease as compared to 11% of younger patients (p=0.103). Mortality rates were 60% in older patients and 19% in younger patients (p=0.001). In multivariate regression analysis age (Beta=0.33 per 1-year, p=0.005), serum creatinine (Beta=0.29 per 1-mg/dL, p=0.011), and lung involvement (Beta=0.36, p=0.002) at the time of diagnosis were independent predictors for end stage renal disease and/or death.
Conclusion: This study documents increased frequency and significant mortality of PSV among older people in Crete, with MPA being the most prevalent type. Age, serum creatinine, and lung involvement are important predictors for adverse outcome in these patients.