Potentially inappropriate medication use in hospitalized elders.

Background: Prescribing of potentially harmful medications has not been well documented in hospitals.

Objective: The objective of the study was to determine the rate of and factors associated with potentially inappropriate medication (PIM) prescribing in a large inpatient sample.

Design: The study was a retrospective cohort of the period between September 1, 2002, and June 30, 2005. We used multivariable logistic regression to identify patient, physician, and hospital characteristics associated with PIM prescribing.

Setting: The study collected data from 384 US hospitals.

Patients: The sample was composed of patients aged >or=65 years admitted with 1 or more of 7 common medical diagnoses.

Measurements: The percentage of patients prescribed PIMs as defined using a modified Beers list was measured. Multivariable-adjusted odds ratios for PIM use were computed.

Results: Of the 493,971 patients, 49% received at least 1 PIM, and 6% received 3 or more, most commonly promethazine, diphenhydramine, and propoxyphene. Patient, physician, and hospital characteristics were all associated with PIM use. Patients with myocardial infarction or heart failure were most likely (61% and 52% vs. 46% for pneumonia), men (47% vs. 49% for women) and those in managed care plans (44% vs. 49% for other plans) were less likely, and patients >or=85 years were least likely (42% vs. 53% for patients aged 65-74 years) to receive PIMs (P < .0001 for all comparisons). For high-severity PIMs, internists and hospitalists had similar prescribing rates (33%), cardiologists had a higher rate (48%), and geriatricians had the lowest rate (24%). The proportion of elders receiving PIMs ranged from 34% in the Northeast to 55% in the South, and variation at the individual hospital level was extreme. At 7 hospitals, PIMs were never prescribed.

Conclusions: Wide variation in the use of PIMs is associated with hospital and physician characteristics. Care may be improved by minimizing this non-patient-centered variation.