Adverse events among medical patients after discharge from hospital

BackgroundAdverse events (AEs) are adverse outcomes caused by medical care. Several studies have indicated that a substantial number of patients experience AEs before or during hospitalization. However, few data describe AEs after hospital discharge. We determined the incidence, severity, preventability and ameliorability of AEs in patients discharged from the general internal medicine service of a Canadian hospital.MethodsAt a multisite Canadian teaching hospital, we prospectively studied patients who were consecutively discharged home or to a seniors'' residence from the general internal medicine service during a 14-week interval in 2002. We used telephone interview and chart review to identify outcomes after discharge. Two physicians independently reviewed each outcome to determine if the patient experienced an AE. The severity, preventability and ameliorability of all AEs were classified.ResultsDuring the study period, outcomes were determined for 328 of the 361 eligible patients, who averaged 71 years of age (interquartile range 54–81 years). After discharge, 76 of the 328 patients experienced at least 1 AE (overall incidence 23%, 95% confidence interval CI] 19%–28%). The AE severity ranged from symptoms only (68% of the AEs) or symptoms associated with a nonpermanent disability (25%) to permanent disability (3%) or death (3%). The most common AEs were adverse drug events (72%), therapeutic errors (16%) and nosocomial infections (11%). Of the 76 patients, 38 had an AE that was either preventable or ameliorable (overall incidence 12%, 95% CI 9%–16%).InterpretationApproximately one-quarter of patients in our study had an AE after hospital discharge, and half of the AEs were preventable or ameliorable.The Institute of Medicine report Crossing the quality chasm identifies patient safety as a prerequisite to high-quality care.¹ The need to improve safety is highlighted by research showing that hospitalized patients have a high risk of adverse outcomes resulting from treatment. For example, the Harvard Medical Practice Study found that adverse events (AEs) occurred in 3.7% of hospitalized patients.^2,3 Similar studies have found equivalent or greater rates.^4,5,6 Other research has found that AE risk increases with design flaws in the health care system.^7,8,9,10Such flaws may particularly affect patient care immediately after hospital discharge, a period associated with discontinuities in providers and in location of care. Some authors suggest that such “gaps” are important causes of error.¹¹ It is also a time when patients frequently experience extensive changes in health¹² and therapy.¹³ Finally, communication between hospital and community physicians can be inadequate.¹⁴ For these reasons, AEs may be common after discharge. A recent study, by a group that included 1 of us, found that 19% of medical patients discharged from a single teaching hospital in the United States experienced an AE within a month.¹⁵ One-third of these AEs were preventable because they were due to an error. Another third were judged “ameliorable” because their severity could have been reduced with better monitoring or earlier response to the problem.¹⁵That study was important, but it had limitations. It was carried out in a single, very specialized institution, it relied on data available in an electronic medical record, and it had a high rate of loss to follow-up. To address these concerns, we carried out a new study to determine the risk, severity and type of AEs after discharge from 2 campuses of a Canadian teaching hospital.