Evaluation of the Validity of International Classification of Diseases Codes for Dermatologic Conditions

Accurate classification of dermatologic conditions using International Classification of Diseases (ICD) codes is essential for research that uses large administrative datasets. Misclassification can be associated with biased epidemiologic estimates and misleading conclusions in population-based studies.

To systematically identify and evaluate validated classification approaches for dermatologic conditions using ICD codes in US-based administrative, claims, or electronic health record data. Evidence Review: A systematic review was conducted that was registered with PROSPERO (CRD420250654233) and reported according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A comprehensive search of Ovid MEDLINE, Embase, Web of Science, and CINAHL was conducted for studies published from January 1, 2000, to October 21, 2025. The data were analyzed in October 2025. Eligible studies evaluated International Classification of Diseases, Ninth Revision (ICD-9) or International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10) codes used to identify dermatologic conditions in US-based datasets and reported at least 1 classification metric (eg, positive predictive value). To minimize selection and extraction bias, all screening and data extraction were performed independently by 2 reviewers, with discrepancies resolved by consensus.