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When TNFi Doses are Reduced, Ankylosing Spondylitis Medical Costs Decrease

March 05, 2021

Among the 17.8% of patients with ankylosing spondylitis who had their initial tumor necrosis factor inhibitor (TNFi) dose reduced over 2 years, medical costs dropped significantly, according to a study published online ahead of print in the journal Rheumatology and Therapy. 

“TNFis may be administered at a reduced dose to patients with ankylosing spondylitis for various reasons,” researchers wrote. “However, in practice, there is insufficient evidence of how the dose reduction of TNFi is implemented and the amount of medical costs it reduces.” 

To investigate the effect of TNFi dose reduction on medical costs, researchers used an insurance claims database in South Korea to identify 1352 patients with ankylosing spondylitis newly treated with TNFis. Patients were categorized according to the TNFi prescribed and followed for 2 years. 

Of the 56.51% of patients who continued TNFi use over 2 years, 17.8% had their doses reduced, according to the study. Per TNFi, the proportion of patients with reduced doses was 24.83% with etanercept, 21.97% with adalimumab, 11.98% with infliximab, and 11.70% with golimumab. 

With dose reductions, total health care costs associated with ankylosing spondylitis decreased 35.52% for the infliximab group, 31.80% for the etanercept group, 26.34% for the golimumab group, and 24.85% for the adalimumab group, the study showed. 

“The cost of AS-related total medical care significantly increased medical cost savings from 24.85% to 35.52% following TNFi dose reduction,” researchers concluded. “If patients with potential for dose reduction are screened well, health care costs may be reduced without worsening disease activity.” 

Jolynn Tumolo


Koo BS, Lim YC, Lee MY, et al. Dose Reduction of Tumor Necrosis Factor Inhibitor and its Effect on Medical Costs for Patients with Ankylosing Spondylitis [published online ahead of print, 2021 Jan 9]. Rheumatol Ther. 2021;10.1007/s40744-020-00274-9. doi:10.1007/s40744-020-00274-9

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