Axonal loss at time of diagnosis as biomarker for long-term disability in chronic inflammatory demyelinating polyneuropathy

Muscle Nerve. 2022 Dec;66(6):715-722. doi: 10.1002/mus.27722. Epub 2022 Oct 26.

Abstract

Introduction/aims: We hypothesized that early, pretreatment axonal loss would predict long-term disability, supported by a pilot study of selected patients with chronic inflammatory demyelinating polyneuropathy (CIDP). To further test this hypothesis, we examined a larger consecutive group of CIDP patients.

Methods: Needle electromyography and motor and sensory nerve conduction studies were carried out in 30 CIDP patients at pretreatment and follow-up 5 to 28 years later. Changes in amplitudes were expressed as axonal Z scores and changes in conduction as demyelination Z scores and correlated with findings of the Inflammatory Rasch-built Overall Disability Scale (I-RODS), the Neuropathy Impairment Score (NIS), and isokinetic dynamometry (IKS).

Results: At follow-up, the median I-RODS score was 73, the NIS was 23, and the IKS was 56%. The median axonal Z score was unchanged at follow-up. Conversely, the corresponding demyelination Z scores improved. The initial axonal loss was correlated with the clinical outcome and was an independent predictor of outcome by multivariate regression analysis. Axonal loss at follow-up was also correlated with the clinical outcome. Only the follow-up demyelination Z score was correlated with the clinical outcomes. Furthermore, the latency until treatment initiation was predictive of all three clinical outcome scores at follow-up, and of axonal loss and demyelination at follow-up.

Discussion: The present study findings indicate that pretreatment axonal loss at diagnosis in CIDP is predictive of long-term disability, neurological impairment, and strength. A delay in treatment is associated with more pronounced axonal loss and a worse clinical outcome.

Keywords: axonal loss; electrophysiological examination; long-term follow-up; prediction of CIDP; prognosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biomarkers
  • Electromyography
  • Humans
  • Neural Conduction / physiology
  • Pilot Projects
  • Polyradiculoneuropathy, Chronic Inflammatory Demyelinating* / diagnosis

Substances

  • Biomarkers