Variation in antipsychotic treatment choice across US nursing homes.

OBJECTIVE: Despite serious safety concerns, antipsychotic medications continue to be used widely in US nursing homes. The objective of this study was to quantify the variation in antipsychotic treatment choice across US nursing homes, and to characterize its correlates.
METHODS: Prescribing practices were assessed in a cohort of 65,618 patients 65 years or older in 45 states who initiated treatment with an antipsychotic medication after nursing home admission between 2001 and 2005, using merged Medicaid; Medicare; Minimum Data Set; and Online Survey, Certification, and Reporting data. We fit mixed-effects logistic regression models to examine how antipsychotic treatment choice at the patient-level depends on patient and nursing home fixed and random effects.
RESULTS: Among antipsychotic medication users, 9% of patients initiated treatment with a conventional agent. After adjustment for case-mix and facility characteristics, 95% of nursing homes had a predicted conventional antipsychotic prescribing rate between 2% and 20%. Individually, patient characteristics accounted for 36% of the explained variation, facility characteristics for 23%, and nursing home prescribing tendency for 81%. Results were consistent in the subgroup of nursing home patients with a diagnosis of dementia. The prescribing physician was not considered as a determinant of treatment choice owing to data limitations.
CONCLUSION: These findings indicate that antipsychotic treatment choice is to some extent influenced by a nursing home's underling prescribing "culture." This culture may reveal strategies for targeting quality improvement interventions. In addition, these findings suggest that a nursing home's tendency for specific antipsychotics merits further exploration as an instrumental variable for improved confounding adjustment in comparative effectiveness studies.