Accuracy of ICD-10 diagnostic codes for identifying housing instability

People experiencing housing instability, which comprises homelessness and other unstable housing circumstances, are at high risk for poor health outcomes. The International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10) includes Z59 diagnostic codes for housing instability, which are assigned by clinicians during health care encounters. Prior research suggests that Z59 codes are used infrequently.This study sought to evaluate the performance of Z59 codes for identifying housing instability during health care encounters using patient-reported data on housing instability as the reference standard to define this exposure.