7 Percent of Outpatients Experience One or More Adverse Event

Among outpatients, 7.0 percent have at least one adverse event (AE), with adverse drug events being the most common, according to a study published online May 7 in the Annals of Internal Medicine.

Noting that knowledge of outpatient AEs remains limited, David M. Levine, M.D., M.P.H., from Harvard Medical School in Boston, and colleagues describe the frequency and types of harm that occurred at 11 outpatient sites during one year. Data were reviewed for 3,103 patients who received outpatient care. Possible AEs were identified by nurse reviewers and adjudicated by physicians.

The researchers found that 7.0 percent of patients had at least one AE (8.6 events per 100 patients per year). The most common AEs were adverse drug events, health care-associated infections, and surgical or procedural events (63.8, 14.8, and 14.2 percent, respectively). AEs were never fatal; 17.4 and 2.1 percent were serious and life-threatening, respectively. Of the AEs, 23.2 percent were preventable. Having at least one AE occurred less often at ages 18 to 44 years versus ages 65 to 84 years (standardized risk difference, −0.05) and occurred more often with Black versus Asian race (standardized risk difference, 0.09). Overall, 1.8 to 23.6 percent of patients had at least one AE across study sites; there was considerable variation observed in the clinical category of AEs.

“We believe these data serve as an urgent call for patient safety research and innovation in the outpatient setting,” the authors write.

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