The use of TNF-inhibitors in ankylosing spondylitis in Austria from 2007 to 2009 – a retrospective analysis

Abstract

The introduction of anti- tumor necrosis factor-alpha agents (TNF-inhibitors) offered new dimensions in symptom relief and alteration of disease progression for patients with Ankylosing Spondylitis (AS). In 2007, Infliximab, Etanercept and Adalimumab were approved for AS in Austria. Drug reimbursement data of 2007 were retrieved to evaluate frequency of prescription, preferred substance and data on switching therapies. Data from eight health insurance funds covering 5.4 million insured people, which corresponds to 64% of the population, was analyzed by linking two databases, combining data on therapy of individual patients and their diagnosis. For those patients on TNF-inhibitors in 2007 reimbursement data from 2008 and 2009 were obtained, respectively. A total of 694 patients with AS on TNF inhibitors in 2007 were identified for data analysis. Yearly costs for TNF-inhibitors were highest for Adalimumab (14,399 € per patient) followed by Infliximab (11,685 € per patient) and Etanercept (10,184 € per patient). In first-time TNF-inhibitor prescriptions, Adalimumab was prescribed most often, with a tendency towards prescription of Adalimumab and Etanercept in the younger and Infliximab in the older population. In the first year of prescription, 12% of patients already switched from the initially prescribed drug to another substance with those started on Etanercept showing the lowest switching rate. One-year drug survival in our data was highest for Etanercept with 83% still on the drug after 1 year, followed by Infliximab and then Adalimumab, while two-year drug survival was also highest for Etanercept (58%), followed by Adalimumab and then Infliximab. Patients with Ankylosing Spondylitis starting on TNF-inhibiting therapy in Austria in 2007 were treated most often with Adalimumab, while Etanercept showed the lowest switching rate and the longest 1- and 2-year drug survival.