Adverse drug events present the single greatest risk of harm to patients in hospitals. Traditional efforts to detect ADEs have focused on voluntary reporting and tracking of errors. However, public health researchers have established that only 10 to 20 percent of errors are ever reported and, of those, 90 to 95 percent cause no harm to patients. Hospitals need a more effective way to identify events that do cause harm to patients, in order to select and test changes to reduce harm. Tracking ADEs per 1,000 medication doses over time is a useful way to tell if changes the team is making are improving the safety of the medication system.

Formula: The total number of ADEs identified in a sample of patient records, divided by the total number of medication doses administered to those patients. Multiply the result by 1,000.

Decrease the number of ADEs per 1,000 doses by 75 percent within 1 year.

Every month, select a random sample of at least 20 closed patient records, each with a minimum stay of two days. (Even better would be a weekly review of 10 records, with data reported as a monthly number of ADEs per 1,000 doses.) Review the records, looking for "triggers" — certain medications, laboratory values, or events — that often provide clues that an ADE has occurred. Investigate each trigger further to determine if an ADE did in fact occur. Obtain the total number of doses administered for each patient from charge codes and units billed to the patient for medications.