BACKGROUND: Although antipsychotics are used for treatment of delirium/agitation in hospitalized patients, their scope of use has not been investigated in a large, multicenter cohort.

OBJECTIVE: To determine rates of use and hospital variation in use of antipsychotics in nonpsychiatric admissions.

DESIGN, SETTING, PATIENTS: Cohort study of adult, nonpsychiatric admissions to 300 US hospitals contributing data to the Premier database, from July 1, 2009 to June 30, 2010.

MEASUREMENTS: Antipsychotic exposure defined using pharmacy charges. Potentially excessive dosing defined using guidelines for long-term care facilities.

RESULTS: Our cohort included 2,695,081 admissions (median age, 63 years; 56% female). Antipsychotic exposure occurred in 160,773 (6%) admissions; 102,148 (64%) received atypical antipsychotics, 76,979 (48%) received typical, and 18,354 (11%) received both. Among exposed admissions, 47% received >/=1 potentially excessive daily dose. Among the variables we analyzed, the strongest predictors of antipsychotic receipt were delirium (relative risk [RR]: 2.93, 95% CI: 2.88-2.98) and dementia (RR: 2.78, 95% CI: 2.72-2.83). After adjustment for patient characteristics, patients admitted to hospitals in the highest antipsychotic prescribing quintile were more than twice as likely to be exposed compared to patients admitted to hospitals in the lowest prescribing quintile (RR: 2.56, 95% CI: 2.50-2.61). This relationship was similar across subgroups of admissions with delirium and dementia.

CONCLUSIONS: Antipsychotic medication exposure is common in nonpsychiatric admissions to US hospitals. The observed variation in antipsychotic prescribing was not fully explained by measured patient characteristics, suggesting the possibility of differing hospital prescribing cultures. Additional research and guidelines are necessary to define appropriate use of these potentially harmful medications in the hospital setting.