Drug Survival Rates of Tumor Necrosis Factor Inhibitors in Patients with Rheumatoid Arthritis and Ankylosing Spondylitis

We investigated the compliance of Korean patients using tumor necrosis factor (TNF) inhibitors to treat rheumatoid arthritis (RA) and ankylosing spondylitis (AS), and identified potential predictors associated with treatment discontinuation. The study population comprised 114 RA and 310 AS patients treated with TNF inhibitors at a single tertiary center for at least 1 yr from December 2002 to November 2011. Of the 114 RA patients, 64 (56.1%) discontinued their first TNF inhibitors with a mean duration of 18.1 months. By contrast, 65 of 310 patients (21.0%) with AS discontinued their first TNF inhibitors, with a mean duration of 84 months. Although the survival rate did not differ among the three TNF inhibitors in the AS patients, the etanercept group had a lower discontinuation rate than the infliximab group in the RA patients. In addition, RA patients who received corticosteroids in combination with TNF inhibitors were more likely to discontinue their TNF inhibitors. The independent predictors of drug discontinuation in AS patients were male gender and complete ankylosis on radiographs of the sacroiliac joint. Our results provide further evidence that real-life treatment outcomes of RA and AS patients may be different from those observed in randomized clinical trials.