Drug therapy for chronic idiopathic axonal polyneuropathy

Chronic idiopathic axonal polyneuropathy is an insidiously progressive sensory or sensorimotor polyneuropathy that affects elderly people. Although severe disability or handicap does not occur, it reduces quality of life.

To assess whether drug therapy for chronic idiopathic axonal polyneuropathy reduces disability, ameliorates neurological symptoms and associated impairments, and whether treatment is safe.

We searched Cochrane Library (Cochrane Neuromuscular Disease Review Group Register, Cochrane Database of Systematic Reviews, Cochrane Database of Abstracts of Reviews of Effectiveness, and the Cochrane Central Register of Controlled Trials), MEDLINE, EMBASE, ISI, and ACP Journal Club's Best Evidence, from 1981 until December 2002. We also hand searched the reference lists of relevant articles, reviews and textbooks identified electronically, and contacted authors and other experts in the field to identify additional studies.

We sought all randomised or quasi-randomised (alternate or other systematic treatment allocation), unconfounded trials that examined the effects of any drug therapy in patients with chronic idiopathic axonal polyneuropathy at least one year after the onset of treatment. Patients with chronic idiopathic axonal polyneuropathy had to fulfil the following criteria: age 40 years or older, distal sensory or sensorimotor polyneuropathy, absence of systemic or other neurological disease, chronic clinical course not reaching a nadir in less than two months, exclusion of any recognised cause of the polyneuropathy by medical history taking, clinical or laboratory investigations, electrophysiological studies in agreement with axonal polyneuropathy without evidence of demyelinating features. The primary outcome was the proportion of patients with a significant improvement in disability. Secondary outcomes were change in the mean disability score, change in the proportion of patients who make use of walking aids, change in the mean Medical Research Council sum score, degree of pain relief and/or reduction of other positive sensory symptoms, change in the proportion of patients with pain or other positive sensory symptoms, and frequency of adverse effects.

Two reviewers independently reviewed and extracted details of trial methodology and outcome data of all potentially relevant trials.

Eighteen studies were identified and assessed for possible inclusion in the review, but all were excluded because of insufficient quality or lack of relevance.

Even though chronic idiopathic axonal polyneuropathy has been clearly described and delineated, no adequate randomised or quasi-randomised controlled clinical treatment trials have been performed. In their absence there is no proven efficacious drug therapy.