PCN171 COST AND HEALTHCARE RESOURCE UTILIZATION (HRU) RESULTING FROM IMMUNE-RELATED ADVERSE EVENTS (IRAES) AMONG PATIENTS RECEIVING IMMUNE CHECKPOINT INHIBITORS (ICIS)

Abstract

Despite the increased use of ICIs among cancer patients, there is limited understanding in real-world economic outcomes resulting from ICI use. This study examined the costs and HRU associated with irAEs in patients receiving ICIs. An observational study was conducted using Premier Healthcare Database, a US national hospital discharge database (Mar 2015-Dec 2017). Twenty-eight distinct types of irAEs per the ASCO practice guidelines were identified. Patients with ICD-9/10 codes for non-small cell lung cancer, renal cell carcinoma, urothelial carcinoma, or Merkel cell carcinoma and at least one irAE during the study period were included. Index inpatient or hospital-based outpatient irAE encounters were defined as the first encounter with a confirmed ICI usage during a 90-day look-back period. Patients were then followed for 90 days post-irAE to determine irAE-related costs and HRU. Among 13,030 ICI patients, 51% experienced at least one irAE, with 15,277 distinct irAEs occurred across these patients. 38% of irAE events were inpatient based while the rest were outpatient based encounters. During the follow-up period, the mean±SD cost was $21,219±25,297 for inpatient index irAEs and $5,951±12,654 for outpatient index irAEs, p<0.001. The mean±SD readmission length of stay (LOS) was 9.1±9.4 days for inpatient index irAEs, and 7.7±7.2 days for outpatient index irAEs, p<0.001. Overall, the highest mean costs were for transverse myelitis ($80,976), toxic epidermal necrolysis ($69,115) and myocarditis ($45,341), while the lowest were for acquired hemophilia ($314), adrenal insufficiency ($3,974) and polymyalgia-like syndrome ($4,395). Approximately half of patients receiving an ICI experienced an irAE that required inpatient or hospital-based outpatient treatment. Patients with inpatient index encounters for irAEs subsequently had significantly higher costs and LOS during the follow-up compared to patients with outpatient index encounters. Future studies should evaluate differences in irAEs between different ICIs to enable patient centered treatment choices.