Ambulatory care visits for treating adverse drug effects in the United States, 1995-2001.

This AHRQ–funded study estimates the national prevalence of adverse drug events by capturing data from outpatient physician visits. Using survey data, investigators report on more than 4 million office visits associated with a diagnostic code for an adverse drug event. Although upward trends over time were not statistically significant, the authors conclude that their findings and methods may offer a mechanism for continued tracking of this important safety concern on a national level.