Timely Diagnosis and Monitoring Key to Preventing CIDP Disability, Study Shows

A recently published retrospective analysis of patients with chronic inflammatory demyelinating polyneuropathy (CIDP) revealed that timing of onset of therapy is critical in preventing long-term disability. Using a cohort of nearly 200 patients, those who started their initial treatment later experienced a worsening disease course, as reflected by a significant deterioration in their Inflammatory Neuropathy Cause and Treatment (INCAT) leg disability score.¹

"Our research highlights the urgent need for advances in the understanding of CIDP, including its risk factors, pathophysiology and therapeutic approaches, and describes the current knowledge gaps that require further investigation and research," Paula Quint, Department of Neurology, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University, Germany, wrote.

The study authors added that, "Regular monitoring of treatment response should be integrated more frequently into clinical routine in order to allow treatment changes in time," and that patients should adopt a “hit hard and early” treatment paradigm.

Published in the Journal of Neurology, the study included 197 patients with CIDP from 2018 to 2022 who had data on clinical examinations, medical letters, laboratory results, antibody status, nerve conduction studies, imaging and biopsy findings. The study mainly aimed to identify potential risk factors that might influence disease progression and overall treatment success. To achieve a more homogenous cohort, 43 patients diagnosed with CIDP variant (according to the 2021 EAN/PNS guidelines) were analyzed separately.

Coming into the study, 56% of patients initially started intravenous immunoglobulins while 39% started prednisolone, either continuously or recurrently. Overall, results showed that the choice of first treatment impacts the chance of responder status and treatment change. While nearly one-third (65%) of the cohort changed to second therapy, 59% of patients initially on immunoglobulins did not switch whereas 88% of those who received prednisolone as their initial treatment switched to a second therapy.

Using the Standard of Care (SOC) definition, more than half (56%; n = 110) of patients responded to their first therapy and were thus assigned to the status SOC-responder. Among those who did respond to SOC, most started with immunoglobulins (61%) or prednisolone (35%). In the SOC-refractory group (39% of cohort), 46% were treated with immunoglobulins, and 42% received prednisolone. Ten patients did not undergo immunomodulatory therapy and were excluded from this analysis.

For patients who commenced therapy within 12 months of their initial symptom manifestation, this group saw a significant (P <.01) decrease in INCAT arm disability scores 36 months after diagnosis, as well as 24 months after diagnosis (P <.05), between 12 and 24 months (P <.05), 12 and 36 months (P <.001), and between 24 and 36 months (P <.01) after diagnosis. In contrast, INCAT leg disability scores among those who started treatment late, past 12 months, were significantly (P < 0.01) lower at diagnosis and showed a significant increase 24 (P < 0.05) and 36 (P < 0.01) months after diagnosis, as well as between 12 and 24 (P < 0.05) and between 12 and 36 (P < 0.01) months after diagnosis.

READ MORE: Beyond Diagnosis: New Data Show Early Nerve Conduction Studies Predict Treatment Outcomes in CIDP

Overall, the mean MRC sum scores of SOC-responder patients showed significant improvement (P < 0.0001) 36 months after diagnosis, and were notably higher than those of SOC-refractory patients at this time point. Additionally, SOC-responder patients experienced significant improvements at 24 months (P < 0.001), as well as between 12 and 24 months (P < 0.01) and between 24 and 36 months (P < 0.001) after diagnosis. In contrast, SOC-refractory patients demonstrated a significant deterioration (p < 0.05) between 24- and 36-months post-diagnosis.

Among the 110 SOC-responders to their first therapy, 31 were sustained SOC-responders, while 15 switched to a SOC-refractory status (transitioned SOC-refractory). At all time points observed (0, 12, 24, and 36 months after diagnosis), investigators observed a higher MRC sum score in sustained SOC-responder patients than those in the transitioned SOC-refractory group, with significant (P <.05) improvement seen between 12 and 36 months after diagnosis.

Both the INCAT arm and leg disability scores were lower for sustained SOC-responder patients at all time points, but the differences were not significant, except for a significant improvement (P < 0.05) in the INCAT arm disability score between 24 and 36 months after diagnosis. Similar to the comparison between SOC-responder and SOC-refractory groups, multiple logistic regression was used to investigate factors favoring sustained SOC-responder status, but none of the tested clinical parameters showed a significant impact on therapy outcomes after 12 months of follow-up.

The study came with a few limitations, including the uneven distribution of patients and selection bias in choosing first treatments. However, the clinical and demographic characteristics were reportedly in line with previous studies, with patients typically diagnosed between the ages of 40 and 60, and a higher prevalence in men. Investigators concluded that early diagnosis and treatment are critical to prevent long-term disability, as further showcased through the deterioration in leg disability scores among those who started late. Early diagnosis using current electrophysiological and supportive criteria may improve disease progression.

REFERENCE
1. Quint P, Schroeter CB, Kohle F, et al. Preventing long-term disability in CIDP: the role of timely diagnosis and treatment monitoring in a multicenter CIDP cohort. Journal of Neurol. 2024;271:5930-5943. doi:10.1007/s00415-024-12548-1