The Diagnostic Accuracy of the Second Revision of the European Academy of Neurology/Peripheral Nerve Society Guideline for Diagnosing Chronic Inflammatory Demyelinating Polyradiculoneuropathy

Background: Diagnosing chronic inflammatory demyelinating polyneuropathy (CIDP) relies on clinical and electrodiagnostic features. In 2021, the European Academy of Neurology/Peripheral Nerve Society (EAN/PNS) revised the CIDP guideline, superseding the 2010 European Federation of Neurological Societies (EFNS)/PNS guideline. This study compares the diagnostic accuracy of both guidelines and evaluates the impact of specific criterion changes and nerve conduction study (NCS) extensiveness. Methods: Patients with CIDP were included if they fulfilled the 2010 EFNS/PNS electrodiagnostic criteria for at least possible CIDP or had a presumptive clinical CIDP diagnosis with objective treatment response. Matched controls were patients with suspected chronic immune-mediated neuropathy who received a diagnosis other than CIDP. Diagnostic accuracy was evaluated using two thresholds: one including possible CIDP and one restricted to (probable/definite) CIDP. The impact of electrodiagnostic criteria changes and NCS extensiveness on diagnostic performance was assessed. Results: We included 339 patients and 339 matched controls. Sensitivity of the 2010 EFNS/PNS guideline was 92% when including possible CIDP and 91% for probable/definite CIDP, with specificities of 67% and 78%, respectively. For the 2021 EAN/PNS guideline, sensitivity was 94% when including possible CIDP and 83% for CIDP, with specificities of 66% and 86%, respectively. Differences were due to sensory criteria and changes in conduction block criteria. Unilateral NCS would miss 77 possible CIDP diagnoses. Conclusion: Sensitivity and specificity were comparable when including possible CIDP, but the 2021 EAN/PNS guideline showed lower sensitivity and higher specificity for CIDP alone. Modifying criteria, including removal of sensory abnormalities, and more extensive NCS enhanced accuracy.