Thirty-six trials in 37 papers (n=1,994) were included: 20 parallel and 16 crossover.
All studies on MS were double-blinded and achieved a quality score of 3 or greater. The follow-up period ranged from 6 to 27 months.
Compared with placebo, IVIG was associated with a statistically significant improvement on the Expanded Disability Status Scale score after 1 year (SMD -0.46, 95% CI: -0.92, 0.01, p=0.05) in patients with relapse-remitting disease (4 trials, n=167), but not at 2 years (2 trials, n=188). The use of IVIG increased the proportion of relapse-free patients (5 trials, n=296) in relapse-remitting and secondary progressive disease (OR 0.24, 95% CI: 0.10, 0.60) and reduced the number of relapses experienced per year (4 trials, n=254) in relapse-remitting patients (SMD -0.82, 95% CI: -1.54, -0.11).
The follow-up period ranged from 6 months to 1 year.
No statistically significant difference in the Hughes' disability grading (2 trials, n=398) or in the odds of death (4 trials, n=447) was observed between IVIG and plasma exchange in patients with a symptom duration of less than 14 days. The combination of plasma exchange followed by IVIG had no significant benefit in comparison with either treatment alone (1 trial, n=379).
Idiopathic chronic inflammatory demyelinating polyneuropathy.
The follow-up period ranged from 2 to 6 weeks.
Compared with placebo, IVIG was associated with a statistically significant reduction in disability scores (4 trials, n=125; SMD -0.67, 95% CI: -1.04, -0.30), as well as with a higher proportion of patients experiencing clinical improvement as defined by the investigators (4 trials, n=152; OR 4.43, 95% CI: 2.20, 8.91). There was no difference in 10-m walk time, 9-hole pegboard time or disability scores between IVIG and prednisolone (1 trial, n=32), or in the Neuropathy Disability Score between IVIG and plasma exchange (1 trial, n=20).
Compared with interferon-alpha, a greater proportion of patients using IVIG experienced a decrease of 20% or more in the Clinical Neuropathy Disability Score (1 trial, n=20; OR 36.00,95% CI: 2.72, 476.28) after 6 months; this benefit was also present at 12 months. Overall disability at 4 weeks was significantly reduced by IVIG in comparison with placebo (1 trial, n=22), although there was no statistically significant difference for the primary outcome of that study which was disability at 2 weeks. Patients assigned to receive IVIG experienced an improvement in neuromuscular symptom scores and in sensory capabilities, whereas none of the patients receiving placebo experienced clinically significant changes (1 trial). Further outcomes available from these small studies are available in the paper.
Multifocal motor neuropathy.
Compared with placebo, IVIG led to a statistically significant mean decrease in Neurologic Disability Score (1 trial, n=16) and increased muscle strength (1 trial, n=6).
Inclusion body myositis.
There was no statistically significant difference between IVIG and placebo (2 trials, n=44) for muscle strength, patient's own assessment of improvement, measurement of arm-outstretched time, or electromyographic testing. There was no statistically significant difference in muscle strength between IVIG combined with prednisone and placebo (1 trial, n=37).
Statistical analyses were not reported for two of the studies of myasthenia gravis, and one study reported no statistically significant difference between IVIG and placebo on the 42-day change of Quantitative Myasthenia Gravis Score and the Myasthenia Gravis-Activities of Daily Living profile.
Brief summaries of the single studies investigating seven other neurologic conditions were provided, although a synthesis was not conducted.