Risk of hospitalization with pneumonia in patients with giant cell arteritis and anti-neutrophil cytoplasmic antibody associated vasculitis.

Abstract

This study aimed to assess the risk of hospitalization with pneumonia (HP) among patients with GCA and ANCA associated vasculitis (AAV). This population-based cohort study identified patients with GCA and AAV diagnosed between 2000 and 2021 using the Danish National Patient Registry. Patients were matched 1:10 with controls on sex and year of birth. Using the pseudo-observation method we evaluated the cumulative incidence proportion (CIP) and risk difference (RD) after one, two and five years. Furthermore, a nested-case control (NCC) analysis was carried out to assess variables affecting the risk of HP. The CIP of HP for 9307 patients with GCA was 6.0% (5.5-6.5), 9.4% (8.8-10.0) and 17.6% (16.8-18.4) after one, two and five years. The RD compared with 92 806 matched controls was 3.0% (2.6-3.5), 3.8% (3.2-4.4), to 5.3% (4.5-6.1). For 2401 patients with AAV, the CIP of HP was 12.6% (11.2-13.9), 17.9% (16.3-19.5) and 28.3% (26.4-30.3) after one, two and five years. Compared with 24 013 matched controls, the RD was 10.1% (8.8-11.5), 14.8% (12.3-15.4) and 20.4% (17.9-21.8). The NCC found comorbidities and immunosuppressive treatment to be associated with higher risk of HP. Patients with GCA or AAV had increased risk of HP compared with matched controls. Comorbidities and recent immunosuppressive treatment were associated with higher risk of HP, highlighting the need for focused preventive strategies.