Direct costs in patients with chronic inflammatory arthropathies on biological therapy: a real-world data study

The aim of the study was to assess the direct costs for the Spanish Health System of patients with chronic inflammatory arthropathies treated with biological therapies in daily clinical practice and to establish possible factors associated with lower costs.

A descriptive, observational and retrospective study was conducted. Patients with rheumatoid arthritis, ankylosing spondylitis and psoriatic arthritis who started a biological therapy between 1 January 2009 and 31 December 2016 were included. Variables related to socioeconomic status, disease and biological therapy were included. The annual cost of biological treatment and other direct medical costs were calculated for each disease. The analysis of costs was based on the National Health Service perspective. The time horizon comprised the 8-year long study period.

A total of 422 biological therapy lines were analysed. The annual biological therapy cost per patient was €12,494±3,865 for rheumatoid arthritis, €11,248±2,763 for ankylosing spondylitis and €12,263±35,155 for psoriatic arthritis (p=0.008). The cost of biological therapies entailed about 80% of the total cost of these diseases. Hospital admission was a factor which contributed to an increasing cost in all these conditions. A longer duration of the biological therapy was associated with lower cost in all the diseases.

The cost of ankylosing spondylitis is lower than that of rheumatoid arthritis and psoriatic arthritis. The biological therapy is the factor with the highest impact on the overall cost of these diseases. Preventing hospital admissions and a higher persistence to the biological therapy can contribute to lower costs for the system.