Intravenous immunoglobulin for chronic inflammatory demyelinating polyradiculoneuropathy

Background Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) causes progressive or relapsing weakness and numbness of the limbs, developing over at least two months. Uncontrolled studies suggest that intravenous immunoglobulin (IVIg) helps. Objectives To review systematically the evidence from randomised controlled trials concerning the efficacy and safety of IVIg in CIDP. Search strategy We searched the Cochrane Neuromuscular Trials Register, MEDLINE, EMBASE and ISI from January 1985 to May 2008. Selection criteria Randomised controlled studies testing any dose of IVIg versus placebo, plasma exchange or corticosteroids in definite or probable CIDP. Data collection and analysis Two authors reviewed literature searches to identify potentially relevant trials, scored their quality and extracted data independently. We contacted authors for additional information. Main results Seven randomised controlled trials were considered eligible including 287 participants. These trials were homogeneous and overall quality was high. Five studies on 235 participants compared IVIg against placebo. One trial with 20 participants compared IVIg with plasma exchange and one trial compared IVIg with prednisolone in 32 participants. A significantly higher proportion of participants improved in disability within one month after IVIg treatment as compared with placebo (relative risk 2.40, 95% confidence interval 1.72 to 3.36). Whether all these improvements are equally clinically relevant cannot be deduced from this analysis because each trial used different disability scales and definitions of significant improvement. In three trials including 84 participants the disability could be transformed to the modified Rankin score, on which significantly more patients improved one point after IVIg treatment compared to placebo (relative risk 2.40, 95% confidence interval 0.98 to 5.83). Only one study included in this review had a long-term follow-up. The results of this study suggest that intravenous immunoglobulin improves disability more than placebo over 24 and 48 weeks. The mean disability score revealed no significant difference between IVIg and plasma exchange at six weeks. There was no significant difference in improvement in disability on prednisolone compared with IVIg after two or six weeks. There were no statistically significant differences in frequencies of side effects between the three types of treatment. Authors' conclusions The evidence from randomised controlled trials shows that intravenous immunoglobulin improves disability for at least two to six weeks compared with placebo, with a number needed to treat of 3.00. During this period it has similar efficacy to plasma exchange and oral prednisolone. In one large trial, benefit of IVIg persisted for 24 and possibly 48 weeks.