Introduction: The introduction of biological and targeted synthetic disease‑modifying antirheumatic drugs (b/tsDMARDs) has improved healthcare and health outcomes in patients with rheumatic inflammatory diseases but their cost is substantial.

Objective: Explore direct treatment costs of patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA), and axial spondyloarthritis (axSpA) using real‑world data from a tertiary single‑center.

Methods: A retrospective study integrating data from two databases: a clinical registry and a healthcare expenses database covering the period from January 2021 to September 2023 was performed. Direct medical costs were calculated from the public payer and the patient perspectives, encompassing fully reimbursed services and out‑of‑pocket expenses.

Results: The study comprised 593 patients with RA (50.6%), PsA (20.3%), and axSpA (29.1%). The annual average per patient direct medical costs were €4635 for PsA, €3891 for axSpA, and €3106 for RA. The highest healthcare costs were driven by b/tsDMARDs, which accounted for 94.7% of total costs in PsA, 91.8% in axSpA, and 90.9% in RA. Anti‑TNF use was highest in axSpA with 61.3% (37.6% biosimilars), 58.3% with RA (41.7% biosimilars), and 34.2% with PsA (17.5% biosimilars). Anti‑IL‑17/IL‑23 agents were used in 42.5% of PsA and 36.9% of axSpA patients, while anti‑IL‑6 in 48.7% of RA patients.

Conclusions: The direct cost of b/tsDMARDs varies across diseases. Expenditures on PsA management were the highest and were mainly associated with the high prices of the drugs used and the lowest share of biosimilar anti‑TNFs. Potential savings can be achieved by reducing the use of expensive agents.