Clinical characteristics of patients requiring emergency hospitalization due to immune-related adverse events: a retrospective study.

Background: Immune checkpoint inhibitors (ICIs) have revolutionized cancer treatment, offering hope for various malignancies by enhancing the immune response against tumors. However, ICIs are associated with unique immune-related adverse events (irAEs), which differ significantly from conventional chemotherapy-induced toxicities. These irAEs, which affect more than 70% of patients and often escalate to severe grades, present substantial clinical management challenges and frequently necessitate emergency hospitalization. Therefore, this study aimed to investigate the clinical characteristics of patients requiring emergency hospitalization due to irAEs during ICI therapy to enhance understanding and improve management strategies.

Methods: This retrospective study evaluated patients who received ICIs at Iwate Medical University Hospital between August 1, 2016, and December 31, 2022, and required emergency hospitalization due to irAEs. Clinical data were extracted from the medical records, including patient demographics, presenting complaints, time from ICI initiation to hospitalization, irAE diagnoses, and treatment outcomes. The Spearman rank correlation coefficient was used to analyze the associations between the chief complaints and irAE diagnoses.

Results: Of 1009 ICI-treated patients, 96 required emergency hospitalization for irAEs. The cohort's mean age was 73 years, with 75.0% of patients being male. Among patients who required emergency hospitalization, a high proportion were undergoing treatment for lung cancer (41.7%). The median hospitalization duration was 87 days. The chief complaints included dyspnea (34.4%) and fatigue (34.4%), with gastrointestinal and respiratory disorders being the most frequent irAEs (35.4%). Significant correlations were observed between dyspnea and respiratory diseases (Rs = 0.66), skin diseases and disorders (Rs = 0.81), pain and musculoskeletal disorders (Rs = 0.59), and diarrhea and gastrointestinal disorders (Rs = 0.49). Corticosteroids were administered to 64.6% of the patients. Despite emergency interventions, 8.3% of patients succumbed to irAEs, while 33.3% resumed ICI therapy after hospitalization.

Conclusions: Emergency hospitalization due to irAEs is a considerable concern in ICI therapy, occurring in 9.5% of treated patients. The high incidence of severe irAEs within the first 3 months of treatment underscores the need for early and vigilant monitoring. This study highlights the importance of recognizing and promptly managing irAEs to improve patient outcomes. Future strategies should focus on developing comprehensive management frameworks and enhancing patient and caregiver education to recognize symptoms that warrant immediate medical attention.