Objective: The aim of the present study was to provide data on the use of immunomodulatory therapies in a population comprising all treated patients with relapsing-remitting multiple sclerosis (RRMS) in Denmark.
Patients and methods: From the introduction of immunomodulatory therapy in Denmark in 1996 through 2003, all patients that started immunomodulatory therapy were followed prospectively with neurological examination and standard laboratory tests every six months, and clinical data were reported to the MS Treatment Register, including relapses, Expanded Disability Status Scale scores and side effects.
Results: From 1996 through 2003 in all 2393 patients had started immunomodulatory therapy for RRMS, of whom 1252 (52.3%) were still on therapy with the same product at follow-up on 1 January 2005, whereas 1141 patients had discontinued or changed immunomodulatory therapy. Multiple Cox regression analysis of the risk of suffering a relapse showed a hazard ratio of 1.48 in patients with three or more relapses in the 24 months prior to onset compared with patients with two relapses or less; the hazard ratio was 0.84 in patients with age 238 years at treatment start compared with patients of age <38, and 1.17 for females compared with males. For disease progression the hazard ratio was 1.24 for age =38 years compared with age 2 37 years. Significant differences were observed in the hazard ratios between the different preparations, probably due to selection bias.
Conclusion: The response to immunomodulatory therapy can be predicted to some extent from demographic variables. Differences between preparations can mainly be ascribed to selection bias, and open studies are not suited for comparison of efficacy between different preparations.