Immune checkpoint inhibitors in the real world: A service evaluation of immune-related adverse event incidence and blood test requesting at Portsmouth Hospitals University Trust.

BackgroundImmune checkpoint inhibitors (ICI) have revolutionised oncology care but can cause immune-related adverse events (irAE) requiring hospitalisation or lifelong treatment. Diagnosing irAE is complex, and laboratory testing is vital; however, ordering appropriate tests at appropriate intervals is challenging because of the abundance of conflicting guidelines. The burden of irAE within the NHS is not well defined, and there may be significant variation in irAE across local areas. This study seeks to inform vital local service planning.Methods1028 ICI patients were identified (2018-2023). Medical records and laboratory data were extracted and anonymised before being analysed using SQL and R to investigate the burden of irAE on hospitals and blood test request patterns by primary tumour origin.ResultsThe overall incidence of irAE was 36.8%, and the most common irAEs were skin rashes, hypothyroidism, colitis, and hepatitis. Increased prescribing of ICI across more tumour types has led to an increase in hospital inpatient days. Monitoring was inconsistent: while standard laboratory tests such as complete blood counts, liver function panel, and urea and electrolytes were frequently requested, guideline-recommended baseline tests, including AST, glucose, and thyroid testing, were significantly underutilised, with inconsistent repeat intervals.ConclusionRising ICI use at PHUT has increased irAE related hospital admissions. Blood test requests between 2018 and 2023 were found to be inconsistent across primary tumour origins, and standardised blood test profiles may help streamline the diagnosis of irAEs, leading to earlier diagnosis and interventions.