We conducted a cohort study of acute, noninfectious liver injury among oral antimicrobial users. Potential
cases were identified in the HealthCore Integrated Research Database (HIRDSM) population between July 1, 2001, and
March 31, 2009, using ICD-9-CM codes primarily for acute and subacute necrosis of the liver, hepatic coma, and
Liver test results were used to confirm case status according to published criteria. Two physician reviewers experienced in
studying acute liver injury (blinded to study drug exposures) evaluated data abstracted from hospital and emergency
department records to validate potential cases. Of 715 potential cases having claims associated with any of the primary
screening codes, 312 (44%) were valid cases, 108 (15%) were not cases, and 295 (41%) were of uncertain status (records
inadequate for validation). Among potential cases with adequate medical records, the PPV for presence of any of the
primary codes was 74% (95% CI, 70%-78%). The highest PPV for a single code was for acute and subacute necrosis of
the liver (84%; 95% CI, 77%-90%).
Evaluation of cases of noninfectious liver injury using hospital and emergency department medical records continues to
represent the preferred approach in studies using insurance claims data.