Incident use and outcomes associated with potentially inappropriate medication use in older adults

Background: Most studies of potentially inappropriate medication (PIM) use among older adults have focused on prevalence rather than incidence.

Objectives: The goals of this study were to determine the 1-year incidence of PIM use among elderly Indiana Medicaid residents of nursing homes and to examine associations between incident PIM use and hospitalization and mortality.

Methods: A retrospective analysis was conducted using Indiana Medicaid enrollment and administrative claims files. Individuals were included if they were Medicaid eligible and aged ≥65 years as of January 2003 and received nursing home services in each month of 2003 or until death in 2003. Individuals also had to receive nursing home services from October 2002 through December 2002 for inclusion in the sample. To focus analysis on incident PIM use, individuals who received any PIM prescription medication from October 2002 through December 2002 were excluded from the sample, as were those not prescribed any new medication in 2003. PIMs were identified using the 2003 Beers criteria. Associations between incident PIM use and hospitalization and mortality were assessed using logistic regression models after controlling for other risk factors. Potential selection bias was examined using bivariate probit models.

Results: The study sample consisted of 7594 individuals (mean age, 83.07 years). A majority of the sample was female (76.5%), white (89.7%), and widowed (58.8%). Most individuals received care in nursing homes located in urban areas (5306 [69.9%]) and in the central region of Indiana (2838 [37.4%]). One-year incidence of PIM use was 42.1%. Incident PIM users were more likely to be hospitalized (odds ratio [OR] = 1.27; 95% CI, 1.10-C1.46) and more likely to die (OR = 1.46; 95% CI, 1.31-C1.62) in the 12 months after first receiving a PIM than nonusers, even after adjusting for demographic and clinical risk factors.

Conclusions: Incident PIM use was high among these elderly Indiana Medicaid residents of nursing homes. Individuals who began use of a PIM were at a higher risk of hospitalization and of dying.