Identifying Patients With Hepatic Encephalopathy Using Administrative Data in the ICD-10 Era

Hepatic encephalopathy (HE) is a common complication of cirrhosis resulting in relapsing-remitting mental status changes ranging from deficits in executive function to coma. Incident HE is associated with an abrupt increase in mortality¹ and frequent hospitalization.² To further the understanding of the burden and impact of HE at the population level, valid algorithms are required to identify patients in administrative data. An International Classification of Diseases (ICD)-9 code is specific for HE (572.2), offering a 0.92 positive predictive value (PPV) and 0.36 negative predictive value (NPV).³ When applied in an algorithm to patients with ICD-9 codes for cirrhosis (eg, 571.5), Kanwal et al⁴ found a PPV and NPV of 0.86 and 0.87. Unfortunately, the switch to ICD-10 in 2015 rendered algorithms validated using ICD-9 invalid. Kaplan et al⁵ previously showed that lactulose and rifaximin use correlated with grade of HE for Child classification. Herein, we validate a diagnostic coding algorithm for HE using ICD-10 and medication records.