Measuring accuracy of International Classification of Diseases codes in identification of patients with non-cystic fibrosis bronchiectasis

Introduction Non-cystic fibrosis bronchiectasis is a disease which is increasing in incidence and prevalence worldwide. The incidence of the disease is frequently estimated using databases that rely on International Classification of Diseases, ninth and tenth revisions, clinical modification (ICD-9-CM/ICD-10-CM) discharge diagnoses. Code accuracy has proved to be a major issue for other diagnoses using ICD codes. This study aims to investigate the accuracy of the ICD codes for the diagnosis of non-cystic fibrosis bronchiectasis. Methods This is a retrospective diagnostic accuracy study which compares the radiologist's diagnosis of bronchiectasis with the ICD code reflection of that diagnosis at discharge. Results Sensitivities were 34% (same for both ICD-9-CM and ICD-10-CM windows) and specificities ranged from 69% for the ICD-9-CM window to 81% for ICD-10-CM window. Conclusion We observed that ICD codes are an insufficient method to identify patients with a radiologist diagnosis of bronchiectasis.