medwireNews: People with rheumatoid arthritis (RA) who switch between different biologic or targeted synthetic DMARDs have a higher risk for venous thromboembolism (VTE) than those who remain on the same treatment, researchers report.
Noting that “[s]witching may be a proxy for higher disease severity or poorly controlled RA,” Huifang Liang (AbbVie Inc, North Chicago, Illinois, USA) and co-investigators say that changing treatment “may be an important and independent risk factor” to include in RA drug safety studies, “particularly those using secondary data sources that lack standardised disease activity measures.”
The researchers used a US claims database to investigate rates of inpatient VTE – including deep vein thrombosis and pulmonary embolism – among 17,726 patients switching between different biologic or targeted synthetic agents between 2007 and 2017, 37,993 patients who remained on their first biologic or targeted DMARD during this time, and 92,509 conventional DMARD users. Tumor necrosis factor (TNF) inhibitors were the most commonly used biologics, while tofacitinib was the only evaluable targeted synthetic agent used in the study.
As reported in RMD Open, the age- and sex-standardized VTE incidence rates were 0.86 per 100 person–years for patients who switched treatment, compared with 0.60 per 100 person–years for those who remained on their first biologic or targeted DMARD and 0.58 per 100 person–years for the conventional DMARD group.
After adjustment for factors including age, sex, VTE history, anticoagulant use, and comorbidities, people who switched treatment once had a significant 35% higher risk for VTE compared with those remaining on their first biologic or targeted DMARD, while those who switched twice had a significant 48% elevated risk.
And switchers had a significant 36% increased VTE risk relative to those taking conventional DMARDs in the adjusted analysis.
These results remained significant when the types of VTE were analyzed separately, with people in the switching group having a 36% elevated risk for deep vein thrombosis and a 47% increased risk for pulmonary embolism relative to conventional DMARD users.
Liang and colleagues note that the elevated risk for VTE among treatment switchers was greater in their unadjusted analysis, which did not control for factors reflecting medication use and comorbidities.
Nonetheless, they point out that the statistically significant associations in the fully adjusted analysis support the concept that switching to an alternative biologic or targeted synthetic DMARD “may be a useful proxy for higher disease severity or poorly controlled RA in patients with other constellation[s] of chronic conditions and risk factors.”
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