Longitudinal risk of serious infections in patients with inflammatory arthritis on immunomodulating therapy compared to controls
Ingrid Egeland Christensen, Siri Lillegraven, Joseph Sexton, Tore K Kvien, Till Uhlig, Sella Aarrestad ProvanAbstract
Objectives
To compare the risk of serious infection across time-cohorts in patients with inflammatory arthritis (IA) initiating their first biologic/targeted synthetic disease-modifying antirheumatic drug (b/tsDMARD), to that of the general population. Secondarily, to compare the development in infection risk during treatment across diagnoses and examine risk dynamics during the course of b/tsDMARD treatment.
Methods
Patients with IA starting their first b/tsDMARD were included from the prospective NOR-DMARD study. Controls were randomly drawn from the general population. Cox-regressions were used to compare the 12-month risk of serious infections across three time-cohorts following initiation (2009–2011, 2012–2014, 2015–2018), and risk during the course of treatment at 6-months intervals up to 24 months.
Results
4309 patients (rheumatoid arthritis (RA)=1581, psoriatic arthritis (PsA)=1032 and spondyloarthritis (SpA) =1696) and 86 640 controls were included. From 2009 through 2018, 51 serious infections occurred during the first year of b/tsDMARD treatment in RA patients, HR 2.42 (95% CI 1.83, 3.21) compared with controls, 52 serious infections were observed in patients with PsA/SpA, HR 1.91 (1.44, 2.52). There were no significant differences in 12-month risk of serious infections during b/tsDMARD exposure between time-cohorts. PsA/SpA patients had a consistently lower risk of serious infection compared with RA patients. The risk of serious infections did not change during treatment course.
Conclusion
Patients with IA starting their first b/tsDMARD between 2009–2018 had a consistently higher 12-month risk of serious infection compared with controls. No change in the risk of serious infection across time-cohorts of b/tsDMARD initiation was observed, nor during treatment course.