INTRODUCTION: CIDP is a debilitating and slowly progressing or relapsing immune-mediated neuropathy. Intravenous immunoglobulin (IVIG) is recommended as first-line therapy for CIDP. The clinical profile of patients with CIDP newly initiating IVIG is not well characterized. This retrospective claims-based cohort study aimed to identify and describe characteristics of US patients with CIDP initiating IVIG treatment.
METHODS: Adult immunoglobulin-naïve patients with CIDP from 2008–2018 were identified via diagnosis coding using the IBM MarketScan Research Databases (full cohort). Clinical and demographic characteristics of new IVIG users were described overall and by initial IVIG product. Logistic regression and propensity score methods were used to evaluate probability of receiving available IVIG treatments based on baseline characteristics.
RESULTS: New IVIG users (n=3975, mean age 57 years) had similar demographics compared with the full cohort (n=32,090, mean age 57 years). Almost all (99%) new IVIG use was started in an ambulatory setting. Forty-one percent of new IVIG users had prior nonimmunoglobulin CIDP treatments (35% high-dose corticosteroids). New IVIG users tended to have greater comorbidity/symptom burden (weakness and/or difficulty walking [61% vs 35%], neuropathic or chronic pain [80% vs 64%], diabetes [33% vs 29%], hypertension [62% vs 52%], hypothyroidism [21% vs 18%], rheumatoid arthritis [19% vs 14%], and other autoimmune disorders [7% vs 3%]) and were more likely to have had diagnostic/laboratory testing than the full cohort. Clinical and demographic characteristics tended to be similar among patients by initial IVIG product; differences in initial IVIG product selection varied by year and geographic region.
CONCLUSIONS: Patients with CIDP initiating IVIG have a heavy burden of symptoms, comorbidities, and diagnostic/laboratory testing. The characteristics of US patients initiating different IVIG products are well balanced, suggesting that IVIG products are generally used interchangeably.
