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Both interferon β-1b (IFNβ-1b) and azathioprine (AZA) are effective in reducing relapse frequency in relapsing-remitting multiple sclerosis (RRMS).1 2 However, no prospective study has compared the efficacy of the two drugs. To assess their clinical efficacy and impact on the patients' quality of life, we performed a pilot study on a small group of patients with RRMS. Patients with at least two relapses during the previous 2 years and EDSS lower than or equal to 3.5 were offered treatment with IFNβ-1b or AZA after information about the efficacy, tolerability, and mode of administration of both drugs, and allocated to one of the two treatments according to the patient's choice. Some patients refused to be treated with either drug, mainly because of the fear of side effects and the negative impact of chronic treatment on their lifestyle; they were followed up according to the same protocol (not treated (NT) group). All patients gave informed consent. Serial neurological evaluations were performed every 3 months for 1 year. At the same times a self administered disease specific questionnaire (MSQOL-54), recently validated in the Italian MS population,3 was filled in and the Hamilton depression rating scale (HD) was administered. Scores for the MSQOL-54 were analysed as previously described3; briefly, the raw scores were linearly transformed into 0–100 scales; the higher the transformed score, the better the patient's quality of life. The two composite scores mental health and physical health were also evaluated. A t test for unpaired samples was used to compare the scores between groups, with adjustment for multiple comparisons. The Kruskal-Wallis test and the two sample Wilcoxon rank sum test were used to compare the change in scores between groups. The main clinical variables were compared using at test for unpaired and paired data.
Thirty two patients were included in the study (11 IFNβ-1b, 10 AZA, 11 NT). The clinical characteristics at entry were similar in the two actively treated groups, whereas in the NT group age was significantly higher than in the AZA group (but not the IFN group) and pretreatment relapse frequency (RF) was lower than in the IFN group (but not the AZA group). After 1 year, RF significantly decreased in both the IFN and AZA treated groups without differences between the two treatments, whereas it was unchanged in the NT group. The EDSS remained stable in the three groups (table). Five of 11 patients treated with IFN had flu-like symptoms on one or more occasions, whereas no side effects occurred in the other two groups.
No significant differences in the HD scores and quality of life profile were found between the three groups at entry. At 6 (data not shown) and 12 months the mental health composite score significantly increased in patients treated with AZA compared with the patients treated with IFN, mainly due to the increase in role limitation for emotional reasons item; no significant differences between the NT group and actively treated groups were seen. No significant changes in HD scores in the three groups were found at 12 months. These results suggest that both AZA and IFNβ-1b are effective in reducing relapse frequency in patients with RRMS. The treatment effect on quality of life has been rarely investigated, with conflicting results: no significant change after 1 year of IFNβ-1b treatment was found by Schwartz et al,4 whereas an improvement on physical items after 5 years was reported by Rice et al.5 In our study, the impact on quality of life was better in patients treated with AZA than in those treated with IFN, mainly due to the improvement in mental score. A direct effect of the drugs on the CNS seems unlikely: no symptoms of neurotoxicity were found in either treatment group and no patients developed depression according to the HD scale. Most likely the improvement of quality of life in patients treated with AZA might be related to different tolerability or to differences in treatment schedules, resulting in a more pronounced and persistent perception of the disease in patients treated with IFN. Due to the few patients, the results of this study need to be verified by a larger randomised comparative trial.
We are indebted to Dr Alessandra Solari, Laboratory of Epidemiology, C Besta National Neurological Institute, Milan, Italy, for performing the statistical analysis of the data.