INTRODUCTION: CIDP is a rare immune-mediated neuropathy with significant burdens. Per guidelines, IVIG is first-line therapy for CIDP. The clinical profile of patients with CIDP newly initiating IVIG is not well characterized. We aimed to identify and describe demographic and clinical characteristics of patients with CIDP in the US initiating IVIG treatment.
METHODS: This claims-based cohort study identified adult immunoglobulin-naïve patients with CIDP from January 1, 2008 to December 21, 2018 via diagnosis coding using the IBM® Watson HealthTM MarketScan® Research Databases. Clinical and demographic characteristics of new IVIG users were described overall and by initial IVIG product. Probability of receiving available IVIG treatments based on baseline characteristics was evaluated by logistic regression and propensity score methods.
RESULTS: Demographics (eg, age, sex, region) were similar between new IVIG users (n = 3975) and the full cohort (n = 32 090). However, new IVIG users, compared with the full cohort, tended to have greater comorbidity and symptom burden, which included weakness and/or difficulty walking (61% vs 35%), neuropathic pain (80% vs 64%), diabetes (33% vs 29%), hypertension (62% vs 52%), leukemia/lymphoma (5% vs 3%), hypothyroidism (21% vs 18%), rheumatoid arthritis (19% vs 14%), other autoimmunity disorders (7% vs 3%), and others, respectively. Median age of new IVIG users was 58 years, and 59% were male. Most (88%) received outpatient treatment, and 41% had prior CIDP treatments other than immunoglobulin (35% high-dose corticosteroids). Ancillary testing consisted of electrodiagnostic testing (63%), cerebrospinal fluid analysis (45%), imaging studies (36%), and nerve biopsy (21%). Clinical and demographic characteristics tended to be similar among patients by initial IVIG product, except for calendar year of index treatment.
DISCUSSION: There was a trend to initiate IVIG in patients with CIDP who had greater comorbidity and symptom burden. No correlation was observed between patient characteristics and selection of initial IVIG treatment; rather, differences in selection varied by year.
CONCLUSIONS: This large, claims-based study of patients with CIDP in the US provides insights on the clinical characteristics of those who newly initiated IVIG.
