Study designs of evaluations included in the review
Placebo-controlled, randomised trials (RCTs) where the clinical parameters, outcome criteria and measurements were reported. Studies which omitted any of these parameters were excluded.
Specific interventions included in the review
Placebo and no treatment (natural history) groups from trials of all experimental drugs. These included azathioprine, cyclophosphamide (CFX), copolymer1, interferon (IFN)-beta, IFN-alpha, IFN-treatment factor (TF), TF, azathioprine-prednisone, CFX-plasmapheresis, and cyclosporin.
Participants included in the review
Progressive and remitting-relapsing MS patients who were treated with placebo. All of the studies included patients who were moderately disabled and who had a similar mean disease duration: 6 to 9 years in placebo-treated patients in trials evaluating both relapse- remitting and progressive patients; 3.1 to 6.4 years in placebo- treated patients in trials evaluating relapsing patients; and 10.4 to 12.6 in placebo-treated patients in trials evaluating progressive patients. The mean age of onset ranged from 27.6 to 36 years (15 studies).
Outcomes assessed in the review
The percentage of patients whose disease worsened according to a definite change in the disability score (DS) was assessed.
How were decisions on the relevance of primary studies made?
The authors do not state how the papers were selected for the review, or how many of the reviewers performed the selection.