[Clinical assessment of the course of relapsing-remitting multiple sclerosis in patients treated with interferon beta].

AIM OF THE STUDY: To analyse retrospectively course of the disease in the patients with relapsing-remitting multiple sclerosis (R-R MS), treated with interferon beta (IFN-beta), to compare clinical data within the periods before, during and after IFN-beta treatment and to refer these parameters to clinical state of patients at the beginning of treatment.

MATERIAL AND METHOD: The study comprised 40 patients (18 men, 22 women, aged 22-55 years) with R-R MS, treated with IFN-beta for at least 12 months, with documented follow-up before the treatment and for at least 12 months after it was discontinued. Annual exacerbation rate (AER) and annual rate of disability progression measured by means of expanded standard disability status scale (ap-EDSS) within the periods before, during and after the IFN-alpha treatment were compared for all the patients and referred to duration of the disease and EDSS score at the beginning of treatment. AER and ap-EDSS were also analyzed for subgroups of patients who were relapse-free or whose EDSS score improved during the treatment.

RESULTS: Mean values of AER and ap-EDSS were significantly lower during the IFN-beta treatment than before and after the treatment. AER during and after the treatment correlated positively with EDSS score at the beginning of the treatment. ap-EDSS during the treatment was significantly lower for the patients with EDSS <3 at the beginning of the treatment than for those with EDSS > or = 3. The patients who were relapse--free during the treatment had significantly lower EDSS score at the beginning of treatment and lower AER after the treatment in comparison with those who had relapses. The patients whose EDSS score improved during the treatment had significantly lower EDSS score at the beginning of treatment and lower AER after the treatment in comparison with those whose EDSS score worsened or remained unchanged. AER and ap-EDSS did not depend upon duration of IFN-beta treatment.

CONCLUSIONS: In patients with R-R MS IFN-beta has significant influence upon course of the disease: it causes decrease in exacerbation rate and slower progression of disability. However, improvement of these parameters persists only during the treatment. Clinical effect of treatment depends on initial stage of disability but does not depend on dynamics of the disease before the treatment. For optimal results of IFN-beta treatment, it should be introduced possibly early in the course of MS.