OBJECTIVES: Accounting for high-dose systemic corticosteroid (SCS) use is critical for unbiased real-world studies of patients with inflammatory or immunological disorders. SCS administration may be recorded as procedural codes for injections/infusions (Healthcare Common Procedural Coding System; HCPCS) or pharmacy-dispensed medications (National Drug Code; NDC). Understanding the patterns of SCS coding is important for the valid design of real-world studies.
METHODS: US patients initiating immunoglobulin (IG) treatment for CIDP or PIDD were identified in IBM MarketScan Research Databases from 2008–2018 and 2012–2018, respectively; high-dose SCS use was determined. Patients identified by each coding system were compared.
RESULTS: Among 3975 patients with CIDP and initiating IG, 1382 (34.8%) had prior high-dose SCS use, identified by HCPCS in 925 (23.3%) patients and NDC in 646 (16.3%) patients (non-mutually exclusive). Compared with NDC-identified patients, HCPCS-identified patients were older, more likely to be male, from Southern US, receiving outpatient IG, and have had back pain, central nervous system disorders, diabetes, dyslipidemia, hypertension, and osteoarthritis. HCPCS-identified patients were less likely to have deep vein thrombosis (DVT), opioid use, or prior use of immunomodulating agents. Among 17,931 PIDD patients initiating IG, 11,576 (64.6%) had prior high-dose SCS use, identified by HCPCS in 8826 (49.2%) patients and NDC in 6342 (35.4%) patients (non-mutually exclusive). Compared with NDC-identified patients, HCPCS-identified patients were older, more likely to be female, from Southern US, receiving outpatient IG, using Medicare, and more often had low Risk Vital Sign scores (disease severity algorithm) and have had cancer, fibromyalgia, inflammatory bowel disease, and obesity. HCPCS-identified patients were less likely to have had pneumonia or DVT.
CONCLUSIONS: HCPCS and NDC identification of high-dose SCS use may elucidate differences in patient populations, which should be considered in real-world studies.
