Objective:

To estimate the prevalence and incidence of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) in the United States (US). 

Background:

CIDP is an immune-mediated neuropathic disorder that predominantly affects the peripheral nervous system. While global incidence and prevalence of CIDP have been reported, no recent, large studies focusing on the US are available. 

Design/Methods:

This retrospective study used Inovalon data from 2016 through 2020, covering nearly 170 million lives and containing professional and institutional medical claims from Commercial, Medicare Advantage, and Medicaid payers. CIDP diagnosis was defined by a patient having two diagnoses ≥30 days apart. We conducted a prevalence estimation of CIDP in 2019 and an incidence estimation across 2018 and 2019. Data collected included CIDP diagnoses, age at initial diagnosis, gender, comorbidities, and race.  

Results:

For the prevalence estimation, 7,482 patients with CIDP were identified and stratified by age groups and gender. Extrapolating this to the US population using census data gave an estimate of 58,405 patients living in the US with CIDP. A raw incidence rate of 3.58 patients per 100,000 patient-years was found which, extrapolated to the US population, gave an adjusted rate of 3.64 per 100,000 patient-years. 

Conclusions:

We observed CIDP prevalence and incidence rates higher than previously reported. This was a relatively short observational study, and CIDP identification relied on billing diagnoses and was limited primarily to Medicaid and commercially insured patients, therefore older patients are likely underrepresented. Additional research to confirm the methodology employed to identify CIDP patients seems warranted.