OBJECTIVES: Chronic inflammatory demyelinating polyneuropathy (CIDP) is a rare neurological sensory and motor disorder, and treatment options include intravenous immunoglobulin (IVIg). The effect of replicating the eligibility criteria from randomized controlled trials (RCTs) in a real-world, claims-based cohort in this population was done in order to evaluate how a real-world population differs from RCT populations.

METHODS: Patients initiating IVIg after diagnosis with CIDP were identified in commercial, Medicare, and Medicaid claims, years 2008-2018 at the first use of IVIg following 6 months without use of immunoglobulins. Comorbidity- and treatment-based exclusion criteria from an ongoing RCT were defined in claims and were applied to the IVIg cohort to observe the resulting decrease in sample size. Not all RCT exclusion criteria could be defined in claims; defined criteria included other neuropathies, multiple sclerosis, Parkinson’s disease, diabetic neuropathy, high-dose systemic corticosteroid use, plasma exchange/plasmapheresis, and immunosuppressant use.

RESULTS: We identified 3,975 IVIg initiators with CIDP prior to applying the RCT exclusion criteria. Of these patients, 75.4% had a diagnosis of another neuropathy, 26.5% had prior corticosteroid use, and 15.9% had diabetic neuropathy/uncontrolled diabetes. Other RCT exclusion criteria were each present in <7% of the sample. After cumulatively applying all criteria, 86.1% of the original sample was excluded.

CONCLUSIONS: The RCT population does not reflect a population of real-world users of IVIg. Replicating RCT exclusion criteria excluded the vast majority of identified IVIg users with CIDP, primarily resulting from one criterion (other neuropathy). While some RCT exclusions may be necessary to reduce misclassification of CIDP status, the resulting RCT-replicated population does not accurately reflect the real-world users of IVIg.