Document resource
Objectives To explore characteristics and treatment of patients with rheumatoid arthritis (RA) with invasive fungal infections (IFIs) and to describe infection details and outcome.Methods IFIs reported to the German RABBIT (Rheumatoid Arthritis: Observation of Biologic Therapy) register between May 2001 and December 2023 were analysed using a two-stage approach. First, a detailed case description, including a comparison of cases by infection outcome, was conducted using routine register data and hospital discharge letters. Second, a multivariable time-dependent Cox regression model was fitted to analyse associations with IFI development using routine register data only.Results Among 22 535 patients with RA, 69 IFIs occurred (incidence rate: 0.65/1000 patient-years), with a case fatality of 35% (n=24). Causative pathogens were Pneumocystis jirovecii (35%), Candida spp (33%) and Aspergillus spp (13%).Patients with IFIs were on average 65.4 years old; 54% were female, 80% ever-smokers, 84% glucocorticoid (GC) users and 91% had any infection-risk associated comorbidity at hospitalisation. IFI development was associated with older age (HR 1.36 per 10 years (95% CI 1.05 to 1.76)), male sex (HR 1.92 (95% CI 1.14 to 3.21)), ever-smoking (HR 2.43 (95% CI 1.35 to 4.37)), cardiovascular disease (HR 3.03 (95% CI 1.80 to 5.10)), chronic lung disease (HR 2.09 (95% CI 1.21 to 3.61)), other autoimmune disease (HR 2.11 (95% CI 1.10 to 4.07)), and the use of GCs (HR 1.17 (95% CI 1.11 to 1.22)).Conclusion In patients with RA, IFIs are rare but life-threatening. They occur particularly in patients who are predisposed to infection due to relevant comorbidities, a history of smoking or both. Except for GC use, the overall impact of targeted RA treatment on the risk of IFI appears to be less relevant than that of multimorbidity.