Evolution of Nerve Conduction Demyelinating Parameters Between Baseline and Treatment Cessation May Not Be Predictive of Relapse in IVIg-Responsive CIDP Patients.

INTRODUCTION/AIMS: Identifying factors associated with short-term relapse is essential for tailoring maintenance treatment on a case-by-case basis in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). We sought to determine whether changes in demyelinating electrophysiological features during treatment could predict relapse after treatment discontinuation in a cohort of CIDP patients.

METHODS: We conducted a retrospective study of patients with CIDP treated with intravenous immunoglobulin (IVIg), all of whom had a first nerve conduction study (NCS) at treatment initiation or during treatment, while the disease was in a stable phase, followed by a second study at the time of treatment discontinuation. Demyelinating features and the degree of axonal loss were determined during each NCS and compared between the two examinations.

RESULTS: Thirty-one consecutive IVIg-responsive CIDP patients were included, with a mean age of 59.1 ± 14.6 years. Twenty (65%) were males. Sixteen patients (52%) relapsed after a mean of 6 months. Most patients demonstrated a reduced total number and type of demyelinating features between the two assessments, but overall, these changes were not different between the relapse and relapse-free groups. Similarly, axonal loss at our first assessment and the progression of axonal loss between our two assessments were not different in the relapse group compared to the relapse-free group.

DISCUSSION: In our population of IVIg responsive CIDP patients, we were unable to demonstrate the predictive value of follow-up nerve conduction studies alone for the risk of relapse. Looking at other biomarkers alone or in combination with NCS is necessary.