Effect of hospitalization on inappropriate prescribing in elderly Medicare beneficiaries.

OBJECTIVES: To determine whether acute hospitalization is associated with a change in potentially inappropriate medication (PIM) use and whether use varies across geographic region.
DESIGN: Observational.
SETTING: Continental United States. PARTICIPANTS: Medicare beneficiaries aged 65 and older hospitalized for acute myocardial infarction (AMI) during 2007-08. MEASUREMENTS: Potentially inappropriate medication use was defined according to the High-Risk Medications in Elderly Adults quality indicator from the Healthcare Effectiveness Data and Information Set. Prevalence of outpatient PIM use was determined at admission and discharge and then used to identify medications discontinued during hospitalization and incident medications started during this period.
RESULTS: Of 124,051 older adults hospitalized for AMI, 9,607 (7.7%) were outpatient PIM users at admission, which increased to 8.6% at discharge (P < .001). Admission PIM rates varied according to geographic region, as did the effect of hospitalization. Admission PIM use was lowest in the northeast and remained unchanged during hospitalization (5.1-5.1%, P = .95). In contrast, admission PIM use was highest in the south and increased significantly during hospitalization (9.9-11.4%, P < .001). PIM use also increased from the long-term perspective, with 6-month period prevalence rates of 22.6% before admission and 24.6% after discharge (P < .001).
CONCLUSION: Despite intervention studies demonstrating up to 80% reduction in PIM use during acute hospitalization, a significant increase in PIM use was observed in a naturalistic setting in Medicare beneficiaries with AMI. Further research is needed to develop an approach to minimizing PIM use in the inpatient setting that is cost-effective and suitable for widespread implementation.