Background/Purpose: Systemic vasculitis encompasses a group of autoimmune diseases involving inflammation of blood vessels. Although a rare disease, vasculitis can present with life-threatening symptoms which pose a significant burden on patients as well as the health care system. Newer studies have demonstrated some association with environmental factors and geographic location. In this study, we compare the epidemiology of vasculitis of farmers to other populations in Alberta in a province-wide study.

Methods: An Alberta intergovernmental data linkage identified all farm families in 1999.Two comparison groups were chosen: a random sample of rural residents and a random sample of urban residents. Vasculitis cases across these groups were determined using linked administrative health data from physician claims and hospital episodes. Data was retrieved from Alberta Health Services, a unifying healthcare provider for all residents of Alberta. This data includes all residents covered under the Canadian universal healthcare system. Descriptive statistics were generated comparing incident cases of vasculitis. Data were collected between April 1, 2000, and March 31, 2021.

Results: A total of 5488 vasculitis cases were found across all populations. Incidence rates varied across the 3 populations with farmers having the highest at 110.6/100,000 person-years followed by rural non-farmers (94.3) and urbanites (71.7).Age adjustment narrowed the variation between the incidence rates, but they remained in the same order: 90.1 farmers, 83.8 rural non-farmers, and 70.7 urbanites. In most cases, ~60% were initially identified by physician claims. Polymyalgia rheumatica accounted for 47% of cases followed by Arteritis Unspecified (15%) and small-vessel vasculitis (14%) with the remainder being distributed among 9 other sub-categories. More males were observed having vasculitis in the farm population (50%) versus rural non-farmers and urbanites (41% and 40% respectively). Age at diagnosis was also higher in the farmer population (66.2 years) compared to rural non-farmers (64.5 years) and urbanites (63.9 years). Urban dwellers with vasculitis used fewer hospital-based health services than farmers and other rural residents.

Conclusion: In this large data set, the farm population in Alberta faces a greater burden of vasculitis compared to others in terms of rates of diagnosis and number of hospital admissions. This study lays the cornerstone for subsequent studies on assessing environmental exposures and the distribution of healthcare resources. Understanding the incidence of disease and relating to health care service intervention is important for access to care and management with vasculitis patients.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/a-population-based-study-of-vasculitis-among-farmers-and-urban-residents-in-alberta/