Background Non-suicidal self-injury and suicide attempts are increasing problems among American adolescents. This study proposed a definition for identifying intentional self-harm injuries (ISHIs) in emergency department (ED) records coded with International Classification of Diseases, 10th Revision, Clinical Modification (ICD-10-CM) codes and sought to estimate: (1) the definition’s positive predictive value (PPV) in a pediatric population treated in one Kentucky ED, and (2) the proportion of Intentional self-harm injuries (ISHIs) with intent to die (i.e., suicide attempt) that cannot be captured by ICD-10-CM codes and can only be identified by a medical record abstraction.
Methods The study definition captured initial encounters for ISHIs based on first valid external cause-of-injury self-harm codes in the ICD-10-CM range X71-X83, T14.91, T36-T65, or T71. Medical records for a random sample of 207 ED discharge records were reviewed following a specified protocol. The PPV for the study definition was reported with its 95% confidence interval (95%CI).
Results The estimated PPV for the study definition’s ability to capture true ISHIs was 88.9%, 95%CI (83.8%, 92.8%). The estimated percentage of ISHIs with intent to die was 45.9%, 95%CI (47.1%, 61.0%). The ICD-10-CM code “suicide attempt” (T14.91) captured only 7 cases, but coding guidelines allow assignment of this code only when the mechanism of the suicide attempt is unknown.
Conclusions This study demonstrated a critical shortcoming in U.S. morbidity surveillance. The ICD-10-CM coding system and coding guidelines do not allow accurate identification of ISHIs with intent to die; modifications are needed to address this issue.