Serious infection risk with TNF inhibitors ‘significantly lower’ in PsA vs. RA
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Among patients treated with TNF inhibitors, the risk for serious infection was “significantly lower” in those with psoriatic arthritis compared with rheumatoid arthritis, according to data published in the Annals of the Rheumatic Diseases.
“Given their immunosuppressive effects, infections related to TNFi treatment is a concern,” Ingrid Egeland Christensen, of Diakonhjemmet Hospital, in Oslo, Norway, and colleagues wrote. “In patients with RA, TNFi therapy is associated with an increased risk of serious infections (SIs) compared with conventional synthetic disease modifying anti-rheumatic drugs (DMARDs). Few observational studies have addressed incidence rates (IRs) of SIs in PsA and studies comparing the risk of SIs between patients with RA and PsA are sparse. The future risk of infections should be considered when making treatment decisions.”
To analyze the incidences of — and compare the risks for — serious infection among patients with RA and PsA who receive TNF inhibitors, Christensen and colleagues examined data from the prospective observational multicenter Norwegian-DMARD (NOR-DMARD) study. The researchers included adults with RA or PsA who started TNF inhibitors between January 2009 and December 2018. They then linked their NOR-DMARD data with the Norwegian Patient Registry to identify any serious infections. Comorbidities were additionally found through linkage with the Norwegian Control and Payment of Health Reimbursement database.
In all, Christensen and colleagues analyzed 3,169 TNF inhibitor treatment courses — 1,778 for RA and 1,391 for PsA — across a total of 2,359 patients. The end of observation was determined at the first occurrence of either the last visit or withdrawal from NOR-DMARD, death, emigration or censor date. The researchers added a 30-day observation period to record infections reported after the last visit. Christensen and colleagues calculated crude incidence rates and incident rate ratios for serious infections, with the risk for serious infection compared between the two disease groups using Cox-regression models.
According to the researchers, the crude incidence rates for serious infection were 4.17 (95% CI, 3.52-4.95) for RA and 2.16 (95% CI, 1.66-2.81) in PsA. Compared with RA, patients with PsA demonstrated a lower risk for serious infections (HR = 0.59; 95% CI, 0.41-0.85) in complete set analysis. The reduced risk among patients with PsA compared with RA remained significant after multiple adjustments, and was consistent across age, gender and disease status.
The researchers noted that patients with RA were significantly older, with a more extensive use of co-medication, than those with PsA.
“This study found a significantly lower risk of SIs in patients with PsA than in patients with RA, during exposure to TNFi,” Christensen and colleagues wrote. “The results need to be interpreted with caution given the many important differences between the RA and PsA population, especially with regards to the use of co-medication. Recognizing the elevated risk in patients with RA supports the heightened awareness of SIs during follow-up of these patients.”