Needs and opportunities for achieving optimal outcomes from the use of medicines in hospitals and health systems

For years, the patient safety literature has been replete with articles describing the scope and breadth of adverse drug events (ADEs) across the continuum of care. In 1991, Leape1 reported that drug complications constituted 19% of total adverse events in hospitalized patients. Bates et al.2 reported in 1995 that medication errors occurred in 5.3% of inpatient medication orders, with 7.5% resulting in an ADE. Later work in the primary care environment revealed 27 ADEs per 100 patients, with 13% identified as serious, 28% as ameliorable, and 11% as preventable.3 Transitions of care are often a source of ADEs as well. In one study, more than 12% of patients discharged from a general medicine service experienced an ADE,4 and a high rate of preventable events among community-dwelling elderly has been reported.5 The costs associated with ADEs are significant, with preventable ADEs resulting in $3.5 billion in hospital admissions and increased lengths of stay.6 Many preventable ADEs are the result of an increasingly complex medication-use system in hospitals and health systems. The components of these complexities are multiple and include increasing patient use of medications, especially high-risk, complex therapies; multiple handoffs and lack of standardization during the medication-use process; and an aging population with multiple chronic conditions.