Deterioration after corticosteroids in CIDP may be associated with pure focal demyelination pattern

BACKGROUND: In the PREDICT study, a randomised controlled trial comparing dexamethasone with prednisolone in patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), almost a quarter of patients deteriorated soon after starting treatment. The primary objective of this post-hoc analysis was to test the hypothesis that a focal demyelination pattern is associated with early deterioration after corticosteroid treatment and to explore whether various clinical characteristics are associated with deterioration after corticosteroid treatment. METHODS: Clinical outcome was categorised into early deterioration and non-early deterioration. A neurophysiologist blinded for treatment outcome scored electrophysiological data into following categories: pure focal versus non-focal distribution of demyelination and no/minor versus moderate/severe sensory involvement. Additionally, we compared electrophysiological and clinical baseline parameters, with emphasis on previously reported possible associations. RESULTS: Early deterioration was found in 7 out of 33 patients (21%). Ten patients had pure focal distribution of demyelination, of whom 5 had early deterioration; 23 patients had non-focal distribution, of whom 2 had early deterioration (p = 0.02). Higher mean median nerve sensory nerve conduction velocity (SNCV) was found in patients with early deterioration compared to patients with non-early deterioration (52.6 and respectively 40.8 m/s, p = 0.02). CONCLUSION: Pure focal distribution of demyelination and lesser sensory electrophysiological abnormalities may be associated with early deterioration in CIDP patients treated with corticosteroids.