Comorbidities in patients with antineutrophil cytoplasmic antibody-associated vasculitis versus the general population

Objective. To evaluate the consultation rates of selected comorbidities in patients with antineutrophil cytoplasmic antibody-associated vasculitis (AAV) compared with the general population in southern Sweden. Methods. We used data from a population-based cohort of patients with AAV diagnosed between 1998 and 2010 in Southern Sweden (701,000 inhabitants). For each patient we identified 4 reference subjects randomly sampled from the general population and matched for year of birth, sex, area of residence, and index year. Using the population-based Skåne Healthcare Register, we identified relevant diagnostic codes, registered between 1998 and 2011, for selected comorbidities assigned after the date of diagnosis of AAV or the index date for the reference subjects. We calculated rate ratios for comorbidities (AAV:reference subjects). Results. There were 186 patients with AAV (95 women, mean age 64.5 yrs) and 744 reference persons included in the analysis. The highest rate ratios (AAV:reference) were obtained for osteoporosis (4.6, 95% CI 3.0-7.0), followed by venous thromboembolism (4.0, 95% CI 1.9-8.3), thyroid diseases (2.1, 95% CI 1.3-3.3), and diabetes mellitus (2.0, 95% CI 1.3-2.9). For ischemic heart disease, the rate ratio of 1.5 (95% CI 1.0-2.3) did not reach statistical significance. No statistically significant differences were found for cerebrovascular accidents. Conclusion. AAV is associated with increased consultation rates of several comorbidities including osteoporosis and thromboembolic and endocrine disorders. Comorbid conditions should be taken into consideration when planning and providing care for patients with AAV.