Exploring healthcare utilisation in patients with ANCA-associated vasculitis in Scotland, UK - A longitudinal multicentre retroperspective linked-data study

Objectives: ANCA-associated vasculitis (AAV) are a set of rare, chronic conditions, which have an increased health burden compared with the general population. The objective was to quantify this burden for Scottish patients with AAV by exploring healthcare utilisation in a well-defined cohort. Methods: NHS Scotland provided longitudinal, historic multicentre data on routinely collected health records from seven centres across Scotland, UK. Included were 543 patients with AAV and up to five matches per patient from the general population (n=2671). Included healthcare utilisation parameters were inpatient hospitalisation, outpatient encounters, accidents and emergencies and associated costs. Poisson and linear regression models were conducted to identify driving factors. Results: Patients with AAV showed significantly higher healthcare utilisation compared to their matches across all included parameters. This increase was sustainable over up to ten years of follow-up. The mean costs per person-year were 4.17 (p