Adverse events, such as medication errors, are a major cause of hospital admissions. This retrospective study of a subset of OPERAM intervention patients who were readmitted with a potentially preventable drug-related admission (DRA) examined whether use of STOPP/START criteria during in-hospital medication review can identify medication errors prior to a potentially preventable DRA. Researchers found that medication errors identified at readmission could not be addressed by prior in-hospital medication reviews because the medication error occurred after the in-hospital review or because recommended medication regimen changes were not provided or not implemented.