Analysis of adverse drug reactions for preventability.

Although preventability criteria have been assessed for all adverse drug reactions (ADRs) investigated at our institution over the past 12 years, a systematic evaluation of the data had not been performed. This project analysed preventability data previously collected to identify the potential areas for process improvements. A 3-year retrospective analysis was performed. All ADRs were categorised by drug, drug class, severity, probability of causality and preventability. Factors involved in preventability were assessed and tallied. Descriptive statistics was used to analyse the data. Most ADRs occurred prior to admission. In the outpatient setting, anticoagulants and anticonvulsants were associated with more preventable ADRs (pADRs) than other drug classes, followed by cardiotonic agents and non-steroidal anti-inflammatory drugs (NSAIDs). For ADRs that occurred in hospitalised patients, antibiotics and opiates were associated with approximately half of all pADRs. The preventability categories most frequently associated with ADRs prior to admission were presence of a toxic drug level and drug-drug interactions, while inappropriate dose, route or frequency was the most common preventability category for inpatient ADRs. The majority of pADRs were moderate in severity in both the in- and outpatient settings. Drugs and drug classes involved in pADRs differ in the in- and outpatient settings. Preventability categories also differ by setting. Most pADRs occur prior to admission in our healthcare system. This presents a challenge in terms of implementing the process changes to reduce the pADRs, as patients in the community are outside our control.