[Cost of illness in axial spondylarthritis for patients with and without tumor necrosis factor inhibitor treatment: results of a routine data analysis].

Background: Tumour necrosis factor-alpha inhibitors (TNFi) are an effective but expensive treatment option in axial spondylarthritis (axSpA) patients who fail to achieve disease control under conventional treatment.
Objective: The aim of this study was to assess the cost of illness in axSpA patients treated with and without TNFi.
Methods: Using German health insurance data, patients with axSpA who newly received TNFi between 2011 and 2015 were identified and matched by age and sex to a reference group of patients with axSpA without TNFi treatment. Costs for services performed in an outpatient setting, inpatient care, pharmacotherapy and for productivity loss due to absence from paid work were analyzed over a 2-year period. In patients treated with TNFi , the 2‑year period included 1 year before and 1 year after the initiation of TNFi.
Results: Data from 1455 axSpA patients who received TNFi treatment were included in the analyses. Costs for services performed in an outpatient setting, inpatient care, pharmacotherapy (excluding TNFi) as well as productivity loss significantly decreased after initiation of TNFi. Mean total costs increased from € 6075 in the year prior to TNFi initiation to € 27,871 in the year after TNFi initiation. Excluding costs for TNFi, total costs decreased by 22% to € 4761. Mean total costs among the reference group of 1455 age and sex-matched axSpA patients who did not receive TNFi remained stable over 2 years: € 3939 in the first year vs. € 3832 in the second year.
Conclusion: Initiation of TNFi treatment led to a sharp increase in the total costs of axSpA patients. Part of this increase was offset by a decrease of costs for services performed in an outpatient setting, inpatient care, pharmacotherapy (excluding TNFi) as well as productivity loss. In patients who did not receive TNFi, the costs remained stable over 2 years.