Validation of International Classification of Diseases (ICD) code-based case definitions of immune checkpoint inhibitor associated inflammatory arthritis from administrative health data

The authors aimed to validate International Classification of Diseases (ICD) code-based case definitions for immune checkpoint inhibitor-associated inflammatory arthritis (ICI-IA) using administrative health data. Their study found that the best-performing case definition, which included at least one ICD code for inflammatory arthritis, achieved a sensitivity of 88% and specificity of 86.7%, indicating that these definitions can effectively support ICI-IA surveillance and research.