Efficacy of long-term prednisone therapy in patients with chronic inflammatory demyelinating polyneuropathy (CIDP): a retrospective cohort study

Introduction. Patients with CIDP respond adequately to steroid therapy and intravenous immunoglobulin (IVIG). However, few patients have access to IVIG in developing countries. little information exists about the clinical response to steroid therapy in Latin American countries. Objective. to describe the long-term functional clinical response (24 months) to prednisone therapy in CIDP patients. Material and methods. A retrospective cohort was conducted. Selection included patients with definitive CIDP diagnosis according to European criteria from the Neuromuscular Diseases clinic of the National Institute of Neurology and Neurosurgery between January 2016 and December 2020. Good response to steroid therapy was defined as with improvement in at least one point on the GBS disability score. Poor response to steroid therapy was defined as patients who did not show improvement in at least one point on the GBS disability score. Patients were evaluated at 3, 6, 12, 18 and 24 months. Results. Forty-seven patients with CIDP were included. Half of them were male and mean age was 46 +/- 15 years. Mean time since symptom onset to diagnosis was 6 (IQR 2-12) months. The most common clinical variant was sensory-motor 57.4%, followed by acute-onset CIDP 21.3% and atypical variants 21.2%. At diagnosis our patients presented: mean GBS disability score of 3 (2.25-4) points, MRC score 39.5 +/- 12 points, independent gait in 17%, mean prednisone dose of 50 mg (32.5-50). Twenty-four months after prednisone therapy, a less mean GBS disability score -1(0-2) points-, mean MRC score 56.3 +/- 5.1 points, independent gait 93% and prednisone dose 1 (0-5) mg. Patients with poor three-month functional clinical response had a delay in diagnosis > 6 months (64.7% vs 27.5%) and atypical clinical variants (47% vs 6.8%). Conclusion. CIDP patients treated with prednisone have good long-term functional clinical response. Delay in diagnosis and atypical variant are common clinical characteristics for poor functional clinical response in treatment with prednisone.