Patterns of hospital admissions and readmissions due to immune-related adverse events in patients with genitourinary cancers.
Authors: He Hongchao , Gajagowni Saivaroon , Varughese Sheeba , Ren Wenhong , Jan Anna , Wang Emily , Rawther-Karedath Anishia , Jonasch Eric , Campbell Matthew T. , Subudhi Sumit Kumar , Alhalabi Omar , Siddiqui Bilal Ahmed 
Published: February 2025

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Background:
Immune checkpoint therapies (ICTs) improve survival in patients with genitourinary (GU) cancers, specifically renal cell carcinoma (RCC) and urothelial carcinoma (UC). However, they also lead to inflammation of normal host organs: immune-related adverse events (irAEs). Severe irAEs may lead to repetitive hospitalizations especially if refractory which affects patients’ ability to receive further anti-cancer therapy. We reasoned that identifying such irAEs may enable clinical quality improvement interventions to improve outcomes.
Methods:
All consecutive patients hospitalized under the Genitourinary Medical Oncology inpatient service at The University of Texas MD Anderson Cancer Center with irAEs over a 14-month period (June 2023 to August 2024) were evaluated. Readmission was defined as re-entry to any hospital within 30 days of an initial discharge. Patient characteristics, ICT regimens, irAE types, treatment strategies, time to outpatient follow-up, and clinical outcomes were analyzed.
Results:
Sixty-seven patients (n=53 male; n=14 female) were admitted at least once for an irAE. The median age was 69 years (IQR: 62.0-75.5). Male predominance was consistent with the sex distribution of the cancers included (RCC, n=42, 63%; UC, n=11, 16%; prostate cancer, n=11, 16%). Gastroenterology-related irAEs were the most common cause of hospitalization, accounting for 45% (30/67) of admissions, primarily due to colitis (n=18) and hepatitis (n=9). Among these cases, 7% (2/30) were classified as grade 4, 80% (24/30) as grade 3, and 13% (4/30) as grade 2. Readmission occurred in 28% (19/67) of patients. Of the readmissions, 42% (8/19) were due to irAEs, 37% (7/19) to non-ICT-related reasons (e.g., disease progression, edema, pulmonary embolism), and 21% (4/19) to infection. Among the 8 readmissions for irAEs, 75% (6/8) were classified as grade 3 and 25% (2/8) as grade 2. Of these, 5 readmissions were attributed to the recurrence of the same irAE (colitis, n=3; hepatitis, n=2). These cases of recurrent irAEs resulted in delayed anti-cancer therapy for a median of 49 days (IQR: 42-57.5). Furthermore, readmissions were potentially preventable in 3 cases (colitis, n=2; hepatitis, n=1) due to delays in initiating biologic therapy, while the remaining 2 cases were associated with delays in outpatient follow-up.
Conclusions:
In this single-department, single-center case series, gastroenterology-related irAEs were the most common cause of irAE-related admissions and readmissions in patients undergoing ICT therapy for GU cancers. Quality improvement efforts to reduce readmission are ongoing at our institution including: (1) Improving clinical education for early detection of symptoms; (2) Shortening time to post-discharge outpatient follow-up; and (3) Optimizing timing and usage of steroid-sparing biologic therapies.