Key messages
• Intravenous immunoglobulin (IVIg) leads to improvement in disability for at least two to six weeks compared with dummy treatment.
• During this time period, IVIg is probably equally effective as plasma-exchange and steroids.
• One study showed that the effect of IVIg persisted for six months, but more research is needed to know whether the benefit persists for longer and what the long-term side effects are.
What is chronic inflammatory demyelinating polyradiculoneuropathy?
Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an illness in which nerves become inflamed, leading to paralysis. The likely cause is that the body attacks its own nerves.
What are possible treatments for chronic inflammatory demyelinating polyradiculoneuropathy?
CIDP usually requires long-term treatment to prevent further disability. There is much debate about the best treatment. One choice is a medicine called immunoglobulin, which is a product made from purified antibodies from human donor blood and which is given through a drip into a vein. Steroid medicines and plasma exchange (a procedure for removing and replacing the plasma component of the blood) are known to be effective.
What did we want to find out?
We wanted to know if immunoglobulin was better than placebo (dummy treatment), plasma exchange, or steroids for improving disability in people with CIDP. We also wanted to know if immunoglobulin had any unwanted effects in this population.
What did we do?
We searched for studies that examined immunoglobulin compared with placebo, plasma exchange, or steroids in people with CIDP. We compared and summarised the results of the studies and rated our confidence in the evidence, based on factors such as study methods and sizes.
What did we find?
Nine studies involving 372 people with CIDP were eligible for this review. Five studies compared immunoglobulin with placebo, one compared immunoglobulin with plasma exchange, two compared immunoglobulin with a steroid called prednisolone, and one compared immunoglobulin with a steroid called methylprednisolone.
Main results
Evidence from five studies showed that immunoglobulin compared with placebo increases the number of people who have significantly improved disability scores after two to six weeks of treatment. For every four people who receive treatment, one experiences a significant improvement. Based on evidence from one study, we can conclude that disability scores are probably better in people treated with immunoglobulin compared with people who receive placebo after 24 weeks of treatment. The risk of serious unwanted effects of immunoglobulin is probably similar to that of placebo.
Results from two other studies showed that immunoglobulin was probably no better than steroids (prednisolone or methylprednisolone) for improving disability. There is probably little or no difference in the risk of severe side effects between immunoglobulin and prednisolone, and there may be little or difference in the risk of severe side effects between immunoglobulin and methylprednisolone. With all treatments, fewer than one in 10 people experienced a severe side effect.
What are the limitations of the evidence?
We are confident that immunoglobulin compared with placebo increases the likelihood of improved disability scores after two to six weeks of treatment. However, we have moderate confidence in most other results, because statistical analysis suggested that the effect of immunoglobulin could be beneficial or harmful.
Each study defined improvement in its own way, and the studies used different measurement scales, so it is difficult to relate them to changes in the clinical condition of people with CIDP. Further research is needed to assess the long-term benefits and harms of immunoglobulin compared with other treatments.
How up to date is the evidence?
This is an update of a review first published in 2002 and last updated in 2013. The most recent search for studies was in March 2023.
Evidence from RCTs shows that IVIg improves disability for at least two to six weeks compared with placebo, with an NNTB of 4. During this period, IVIg probably has similar efficacy to oral prednisolone and IVMP. Further placebo-controlled trials are unlikely to change these conclusions. In one large trial, the benefit of IVIg compared with placebo in terms of improved disability score persisted for 24 weeks. Further research is needed to assess the long-term benefits and harms of IVIg relative to other treatments.
Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) causes progressive or relapsing weakness and numbness of the limbs, which lasts for at least two months. Uncontrolled studies have suggested that intravenous immunoglobulin (IVIg) could help to reduce symptoms. This is an update of a review first published in 2002 and last updated in 2013.
To assess the efficacy and safety of intravenous immunoglobulin in people with chronic inflammatory demyelinating polyradiculoneuropathy.
We searched the Cochrane Neuromuscular Specialised Register, CENTRAL, MEDLINE, Embase, and two trials registers on 8 March 2023.
We selected randomised controlled trials (RCTs) and quasi-RCTs that tested any dose of IVIg versus placebo, plasma exchange, or corticosteroids in people with definite or probable CIDP.
We used standard Cochrane methods. Our primary outcome was significant improvement in disability within six weeks after the start of treatment, as determined and defined by the study authors. Our secondary outcomes were change in mean disability score within six weeks, change in muscle strength (Medical Research Council (MRC) sum score) within six weeks, change in mean disability score at 24 weeks or later, frequency of serious adverse events, and frequency of any adverse events. We used GRADE to assess the certainty of evidence for our main outcomes.
We included nine RCTs with 372 participants (235 male) from Europe, North America, South America, and Israel. There was low statistical heterogeneity between the trial results, and the overall risk of bias was low for all trials that contributed data to the analysis. Five trials (235 participants) compared IVIg with placebo, one trial (20 participants) compared IVIg with plasma exchange, two trials (72 participants) compared IVIg with prednisolone, and one trial (45 participants) compared IVIg with intravenous methylprednisolone (IVMP). We included one new trial in this update, though it contributed no data to any meta-analyses.
IVIg compared with placebo increases the probability of significant improvement in disability within six weeks of the start of treatment (risk ratio (RR) 2.40, 95% confidence interval (CI) 1.72 to 3.36; number needed to treat for an additional beneficial outcome (NNTB) 4, 95% CI 3 to 5; 5 trials, 269 participants; high-certainty evidence). Since each trial used a different disability scale and definition of significant improvement, we were unable to evaluate the clinical relevance of the pooled effect. IVIg compared with placebo improves disability measured on the Rankin scale (0 to 6, lower is better) two to six weeks after the start of treatment (mean difference (MD) −0.26 points, 95% CI −0.48 to −0.05; 3 trials, 90 participants; high-certainty evidence). IVIg compared with placebo probably improves disability measured on the Inflammatory Neuropathy Cause and Treatment (INCAT) scale (1 to 10, lower is better) after 24 weeks (MD 0.80 points, 95% CI 0.23 to 1.37; 1 trial, 117 participants; moderate-certainty evidence). There is probably little or no difference between IVIg and placebo in the frequency of serious adverse events (RR 0.82, 95% CI 0.36 to 1.87; 3 trials, 315 participants; moderate-certainty evidence).
The trial comparing IVIg with plasma exchange reported none of our main outcomes.
IVIg compared with prednisolone probably has little or no effect on the probability of significant improvement in disability four weeks after the start of treatment (RR 0.91, 95% CI 0.50 to 1.68; 1 trial, 29 participants; moderate-certainty evidence), and little or no effect on change in mean disability measured on the Rankin scale (MD 0.21 points, 95% CI −0.19 to 0.61; 1 trial, 24 participants; moderate-certainty evidence). There is probably little or no difference between IVIg and prednisolone in the frequency of serious adverse events (RR 0.45, 95% CI 0.04 to 4.69; 1 cross-over trial, 32 participants; moderate-certainty evidence).
IVIg compared with IVMP probably increases the likelihood of significant improvement in disability two weeks after starting treatment (RR 1.46, 95% CI 0.40 to 5.38; 1 trial, 45 participants; moderate-certainty evidence). IVIg compared with IVMP probably has little or no effect on change in disability measured on the Rankin scale two weeks after the start of treatment (MD 0.24 points, 95% CI −0.15 to 0.63; 1 trial, 45 participants; moderate-certainty evidence) or on change in mean disability measured with the Overall Neuropathy Limitation Scale (ONLS, 1 to 12, lower is better) 24 weeks after the start of treatment (MD 0.03 points, 95% CI −0.91 to 0.97; 1 trial, 45 participants; moderate-certainty evidence). The frequency of serious adverse events may be higher with IVIg compared with IVMP (RR 4.40, 95% CI 0.22 to 86.78; 1 trial, 45 participants, moderate-certainty evidence).