Pharmacovigilance - The next chapter

The discovery and quantification of adverse drug reactions has long relied on the careful analysis of spontaneously reported cases. Causality assessment (imputation) was a fundamental feature of individual case report analysis. This was complemented by analysis of aggregated cases, and of disproportionality analyses in spontaneous reports databases. In the absence of more specific information sources, these have resulted in the discovery of many new adverse reactions, altering drug information. It has led to the withdrawal from the market of many drugs, but its use for risk quantification remains fraught with uncertainty. The recent access to population-wide claims or electronic health records databases have confirmed for spontaneous reporting a predominant role in hypothesis generation for serious adverse drug reactions, notably those that result in hospital admission or death. In these cases, the events are identifiable at the population level, and can be quantified precisely using the tools of modern pharmacoepidemiology, to generate specific benefit-risk analyses. Spontaneous reporting remains irreplaceable in signal and alert generation in drug safety, despite its inherent limitations. For signal strengthening and assessment, more systematic and quantitative methods should be sought, such as claims databases for reactions resulting in hospital admissions.

Detection of adverse drug reactions through the minimum basic data set

OBJECTIVE

To analyze adverse drug reaction (ADR) detection using the Minimum Basic Data Set (MBDS) at hospital discharge and to compare the ADR reporting rate to the Pharmacovigilance Referral Centre with other similar hospitals that do not use this reporting system. Setting 650-bed University Hospital serving a population of 294,000 inhabitants in Spain.

METHOD

A retrospective descriptive study was conducted between January 2006 and December 2007. All reports of ADRs gathered in MBDS (a tool that encodes all administrative and clinical information generated for each patient during a hospitalization episode) with International Classification Disease codes between E930 and E949.9 were analyzed to assess the appropriateness of their referral to the pharmacovigilance centre. Finally, we compared our reporting rate with other hospitals that do not use this system for ADR identification.

MAIN OUTCOME MEASURE

The incidence of ADRs detected in hospitalized patients and the reporting rate (per thousand inhabitants) to the referral pharmacovigilance centre using the Yellow Card system.

RESULTS

Out of 43,282 hospital discharges, 386 ADR were recorded (0.89% of hospitalized patients). The mean (+/-SD) age of patients with reported ADR was 61.9 years (+/-19.2), median age was 65 years, and 55.2% were female. The Department of Pharmacy reported 276 (71.5%) of ADR using the Yellow Card system. The most frequently reported drugs were anti-cancer agents (42.5%) and cardiovascular drugs (23.8%), with a high frequency of digitalis glycosides (18.4%). ADR were most frequently recorded by the Departments of Oncology (41.7%) and Internal Medicine (17.9%).

CONCLUSION

The MBDS is a useful and accessible instrument to determine the incidence of ADR in a hospital, resulting in the notification of severe events that might otherwise not be reported. Its use also improves identification of the main drugs responsible for ADR and of the patient populations at greatest risk, facilitating the implementation of alert systems and the development of prevention and detection strategies.