Drivers of hospital costs in ANCA-associated vasculitis patients with long-term follow-up - a real-world cost analysis

Background ANCA-associated vasculitis (AAV) is a potentially life-threatening, systemic auto-immune disease with a high risk for relapse and treatment-related toxicity, making AAV a high-costs illness. This study aimed to identify clinical insights for clinicians on considering this costs-burden. Methods We conducted a detailed, retrospective, single-centre, activity-based cost-analysis and identified clinical variables associated with increased costs. We analyzed real-world costs incurred by the hospital between January 2018 and December 2019, omitting the outpatient pharmacy expenditures. Our cohort included both incident and prevalent AAV patients with at least 6 months follow-up since diagnosis, indicating survival beyond initial diagnosis. Results For 180 AAV patients with a median follow-up of 1.8 years the average hospital costs incurred amounted to €9887 per patient year, with inpatient care being the primary cost driver (32%). Merely 15% of costs were attributable to patients experiencing relapse (N = 14/180, 8%). More importantly, 71% of costs were attributable to patients experiencing infections (N = 77/180, 43%). Likewise, 60% of costs were attributable to patients with multi-comorbidity (N = 65/180, 36%). Infections and multi-comorbidity were both strongly associated with corticosteroid-use. Regression and sensitivity analyses suggest that a reduction of infections, comorbidities and maintenance treatment with corticosteroids will reduce hospital costs. Conclusion This real-world cost analysis demonstrates that the burden of infections and comorbidities, both related to corticosteroid-use, is higher than that of relapses on hospital costs in AAV patients. Thus, this study implicates clinicians considering hospital costs should focus on reducing corticosteroids and achieving corticosteroid-free remission to prevent infections and comorbidities.