No statistically significant difference in mortality rates between three tumor necrosis factor-alpha inhibitor therapies was found in patients with rheumatoid arthritis, according to researchers.
The population-based study linked data on patients with rheumatoid arthritis (RA) in the Swedish Biologics Register (ARTIS) and information from national Swedish registers on causes of death, demographics and RA characteristics and comorbidities. Patients with RA began first-ever tumor necrosis factor-alpha inhibitor (TNFi) therapy with adalimumab (ADA; n=1,609), etanercept (ETA; n=2,686) or infliximab (INF; n=2,027) between 2003 and 2008 (median age at baseline, 57 years; 76.5% women). Measures of disease activity from ARTIS included Disease Activity Score 28, C-reactive protein, erythrocyte sedimentation rate, tender and swollen joint counts, and disease duration.
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Two hundred eleven patients (3.3%) died during more than 19,100 person-years of follow-up (1.1 deaths per 100 person-years), with 85% of deaths occurring among patients exposed to only one TNFi. The most common underlying causes of death were neoplasm (30.3%), followed by circulatory system (26.5%), musculoskeletal system and connective tissue (12.8%), and respiratory system (8.5%) diseases.
“We know that although [ETA, ADA and INF] are all TNF inhibitors, they are also distinct biological entities,” researcher Julia Fridman Simard, ScD, assistant professor at Karolinska Institute in Stockholm, Sweden, told Healio.com. “We wanted to investigate whether these differences translate into clinically significant differences in [RA].”
Adjustments and modeling approaches made little statistical difference in overall mortality among the three groups: INF vs. ETA (RR=1.1; 95% CI, 0.7-1.7) and ADA vs. ETA (RR=1.3; 95% CI, 0.9-2.0). Researchers found statistically significant differences, however, between ETA vs. ADA and INF (separately) as they studied patient subsets, identifying at least four stratum-specific risks.
“With respect to mortality, we found no major differences between the three most commonly prescribed TNF-inhibitor therapies,” Simard said. “These are complex therapies that are not only potent and effective, but also expensive − our findings are in line with what most rheumatologists would hope for.”
Disclosure: See the study for a full list of relevant disclosures.