Survival of disease-modifying antirheumatic drugs used as the first antirheumatic medication in the treatment of ankylosing spondylitis in Finland. A nationwide population-based register study.

The tight national drug reimbursement regulations in the treatment of ankylosing spondylitis (AS) in Finland lead to the practice that at least one traditional disease-modifying antirheumatic drug (DMARD), if not contraindicated, has been tried and has failed before a patient can be eligible for reimbursement of anti-tumour necrosis factor (TNF) treatment. The aim of the present study is to evaluate drug survival of the firstly prescribed DMARDs in patients with AS. All AS patients from January 1, 2000 to December 31, 2007 were collected from the nationwide drug reimbursement registry maintained by the Social Insurance Institution (SII). Data on antirheumatic medication came from the prescription registry of SII. A total of 2,890 AS patients (60 % males) were identified. Sulfasalazine (SSA) monotherapy was the most common first antirheumatic treatment (2,319 patients, 87 %), followed by methotrexate (MTX) monotherapy (230 patients, 9 %) and by hydroxychloroquine monotherapy (77 patients, 3 %). A combination of two or more DMARDs was used by 44 patients (2 %). Only seven patients (0.3 %) had biological (etanercept or adalimumab) started as the first antirheumatic drug. Median survival time of SSA monotherapy was 4.5 years (95 % CI 4.2 to 4.8) and that of MTX was 1.9 years (95 % CI 1.5 to 2.1). SSA is almost the standard as the first antirheumatic treatment of AS in Finland. Although the clinical efficiency of SSA was not evaluable in the present study, these data suggest that the use of SSA can at least postpone the need and start of TNF inhibitors with marked economic consequences.