Detection and incidence of drug-induced liver injuries in hospital: a prospective analysis from laboratory signals.

AIMS: Liver damage remains the most frequent type of adverse drug reaction (ADRs) that can lead to the withdrawal of a drug from the market. The abnormal laboratory data identified by computerized hospital information systems can be used in order to improve the detection of ADRs. Our objectives were to assess the detection and incidence of drug-induced liver abnormalities in a university hospital inpatient population and to evaluate the underreporting rate of drug-induced liver injury.
METHODS: We conducted a prospective study performed 1 week per month from June to October 1997. We selected patients by a computerized process using biochemistry laboratory data, based on serum enzyme values, alanine aminotransferase (over 2 fold normal) and alkaline phosphatase (over 1.5 fold normal).
RESULTS: Among 1976 ALT and 1814 AP assays performed during the period of the study, 156 (7.9%) and 159 (8.8%) tests, respectively, fell into the selected criteria. These concerned 147 patients. Among these patients, 13 (8.8%) cases of drug-induced liver injuries were suspected. Seven cases were asymptomatic. Six cases were classified as serious by these criteria: hospitalization to investigate the cause of health status impairment (4 patients), prolongation of hospitalization (1 patient) and life-threathening (1 patient). Using the hospitalization database, the incidence of drug-induced liver injuries was estimated as 6.6 per 1000 inpatients a week. Only 1 case was reported by physicians in the same period.
CONCLUSIONS: Computerization of biochemical data would allow the development of systems to improve detection of drug-induced injury. Moreover, underreporting remains important for such potentially serious ADRs, even in a university hospital.