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.
Researchers have reviewed systematically the evidence from randomised controlled trials ( RCTs ) concerning the efficacy and safety of IVIg in chronic inflammatory demyelinating polyradiculoneuropathy.
Eight RCTs, including 332 participants, were considered to be eligible for inclusion in the review. These trials were homogeneous and the overall risk of bias low.
Five studies, in a total of 235 participants compared intravenous immunoglobulin against placebo. One trial with 20 participants compared intravenous immunoglobulin with plasma exchange, one trial compared intravenous immunoglobulin with Prednisolone in 32 participants, and one trial, newly included at this update, compared IVIg with intravenous Methylprednisolone in 46 participants.
A significantly higher proportion of participants has improved in disability within one month after IVIg treatment as compared with placebo ( risk ratio, RR=2.40; number needed to treat for an additional beneficial outcome 3.03, high quality evidence ).
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 score could be transformed to the modified Rankin score, on which improvement of one point after IVIg treatment compared to placebo was barely significant ( RR=2.40 ) ( moderate quality evidence ).
Only one placebo-controlled 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 ( moderate quality evidence ).
There was no significant difference in improvement in disability on Prednisolone compared with IVIg after two or six weeks, or on Methylprednisolone compared to IVIg after two weeks or six months ( moderate quality evidence ).
There were no statistically significant differences in frequencies of side effects between the three types of treatment for which data were available ( IVg versus placebo or steroids ) ( moderate or high quality evidence ).
Mild and transient adverse events were found in 49% of participants treated with IVIg, while serious adverse events were found in 6%.
The evidence from RCTs has shown that intravenous immunoglobulin improves disability for at least two to six weeks compared with placebo, with an NNTB of three. During this period it has similar efficacy to plasma exchange, oral Prednisolone and intravenous Methylprednisolone.
In one large trial, the benefit of intravenous immunoglobulin persisted for 24 and possibly 48 weeks.
Further research is needed to compare the long-term benefits as well as side effects of IVIg with other treatments. ( Xagena )
Eftimov F et al, Cochrane Database Syst Rev. 2013 Dec 30;12:CD001797. doi: 10.1002/14651858.CD001797.pub3.