Exploring variation in rates of polypharmacy across long term care homes.

Objective: Use of multiple, concurrent drug therapies, often referred to as polypharmacy, is a concern in the long term care (LTC) setting, where frail older adults are particularly at risk for adverse events. We quantified the scope of this practice by exploring variation in the use of nine or more drug therapies across LTC homes.

Design: Cross-sectional analysis of LTC home census data.

Setting: All LTC homes in Ontario, Canada.

Participants: A total of 64,394 LTC residents aged 66 years and older residing in 589 LTC homes in the fall of 2005.

Measurements: Facility-level rates of polypharmacy were compared with rates of use of Beers criteria and antipsychotic drug therapies. Multivariate logistic regression models were used to assess predictors of polypharmacy across residents and LTC homes.

Results: Nine or more drug therapies were dispensed concurrently to 10,007 (15.5%) of LTC home residents. Compared with those dispensed fewer drugs, residents receiving 9 or more drug therapies were more likely to have multiple comorbidities. There was threefold variation in polypharmacy rates across homes (26.2% versus 7.9%) and facility-level rates of polypharmacy were modestly correlated with rates of use of Beers criteria drugs (r = 0.27, P < .001) and antipsychotic drug therapies (r = 0.16, P < .001). Controlling for resident factors, those living in LTC homes with high polypharmacy rates were more likely to receive 9 or more drug therapies (odds ratio 1.9, 95% confidence interval 1.7-2.0).

Conclusion: Residents in Ontario LTC homes commonly received nine or more concurrent drug therapies, particularly residents with multiple chronic conditions. The threefold variation in rate across homes suggests a role for this measure in guiding drug review at the facility level.