A 10-year matched-pairs study comparing azathioprine and no immunosuppression in multiple sclerosis.

In a retrospective matched-pairs study the efficacy of azathioprine treatment was compared with no treatment over a period of at least 10 years. Of 277 patients with clinically definite multiple sclerosis seen during the years 1973 and 1974, 42 pairs were selected by similarity in disability score, sex, age and disease duration. Only 3 patients were lost to follow-up, and in 2 cases the initial diagnosis could not be confirmed. At the end of the 10-year period the number of wheelchair-bound, bedridden or deceased patients was double in the untreated as compared with the azathioprine-treated group but the number of non- or only minimally handicapped patients was similar in each group. The mean disability score was significantly lower in the treated group. Although caution is warranted as in every retrospective study because of insufficiently controlled confounding variables, these results support a positive but weak long-term effect of azathioprine.