A new national active surveillance system designed to detect adverse drug events is very good at picking up true cases, but not particularly sensitive—especially when it comes to detecting hypoglycemia due to diabetes medications and bleeding associated with anticoagulants, the Centers for Disease Control and Prevention recently reported.
In 2003, the CDC collaborated with the Consumer Product Safety Commission and the Food and Drug Administration in developing the National Electronic Injury Surveillance System-Cooperative Adverse Drug Event Surveillance (NEISS-CADES) project. Because adverse drug events (ADEs) are often more difficult to identify than other injuries, the CDC conducted an independent chart review in a sample of six NEISS-CADES hospitals, representing a range of sizes and of ADE reporting rates (0.2%-1.7% of emergency department visits).
Of 4,561 ED visit charts reviewed, a total of 68 ADE cases were identified. The patients had a median age of 57 years and 53% were female. Of the 29 ADE cases that had been reported to NEISS-CADES prior to the chart review, 25 were among the 68 cases detected by the reviewers. The remaining four cases were false-positives in which an injury attributed to a drug in the chief complaint section of the chart was not confirmed elsewhere in the chart, the CDC explained (MMWR 2005:54;380-3).
The estimated sensitivity of the NEISS-CADES for ascertaining ADEs was 0.33, while the estimated positive predictive value of a reported ADE to the system was 0.92. The relatively low sensitivity of the system was attributed to the difficulty in detecting hypoglycemia associated with diabetes agents, and of bleeding associated with anticoagulants such as warfarin and heparin.