Positive Predictive Value of ICD-10 Codes for Cerebral Venous Sinus Thrombosis in Taiwan’s National Health Insurance Claims Database

OBJECTIVE: This study aims to determine the positive predictive value (PPV) of case definitions for cerebral venous sinus thrombosis (CVST) in Taiwan’s National Health Insurance claims database based on the International Classification of Diseases, 10th Revision, Clinical Modification (ICD-10-CM) diagnostic codes. STUDY DESIGN AND SETTING: Inpatient records with ICD-10-CM codes of G08, I629, I636, or I676 were retrieved from the claims data of all hospital branches of Chang Gung Medical Foundation. Manual review of the medical records and images was performed in order to ascertain the diagnosis. The PPV of various case definitions for CVST was estimated. RESULTS: Of the 380 hospitalizations, 166 and 214 were determined to be true-positive and false-positive episodes of acute CVST, respectively. The PPV of the ICD-10-CM codes of G08, I629, I636, and I676 was 88.2%, 2.0%, 100.0%, and 91.3%, respectively. The PPV generally increased when acute CVST was defined as a primary diagnosis or as ICD-10-CM codes plus anticoagulant use. Miscoding in other conditions, tentative diagnosis, and remote episode of CVST were determined as the main reasons for false-positive diagnosis of acute CVST. CONCLUSION: This study determined the PPV of ICD-10-CM codes for identifying CVST, which may offer a reference for future claims-based research.