Excessive polypharmacy and potentially inappropriate prescribing in 147 care homes: a cross-sectional study

Background: Care-home residents often have multiple cognitive and physical impairments and are at high risk of adverse drug events (ADEs).

Aim: Describe excessive polypharmacy and potentially inappropriate prescribing predisposing care-home residents to ADEs.

Design and Setting: Cross-sectional analysis of all dispensed prescriptions for residents of 147 care-homes.

Method: Prevalence of excessive polypharmacy was examined using multilevel logistic regression, by modelling associations between individual and care-home predictors with excessive polypharmacy (≥10 drugs). Prescribing of drugs known to increase the risk of eight clinically important ADE categories was examined. Drugs prescribed within each ADE category, for each resident, were counted.

Results: 32.3% of residents had excessive polypharmacy, which was more common in residents aged 70-74 years (aOR =1.86 [1.04-3.34]) and 80-84 years (aOR =1.75 [1.01-3.02]), living in a residential care-home (aOR =1.50 [95%CI 1.19-1.88]), and located in Fife (aOR =1.37 [1.09-1.71]). Excessive polypharmacy was less common in residents with dementia (aOR =0.73 [0.64-0.84]). 8.9% (5.9%-11.6%) of the variation was attributable to care-home predictors. Potentially inappropriate prescribing of ≥2 drugs was seen across all ADE categories with highest prevalence seen in drugs predisposing to constipation (35.8%), sedation (27.7%), and renal injury (18.0%).

Conclusions: Excessive polypharmacy is common in care-home residents and is associated with both individual and care-home predictors. Potentially inappropriate prescribing of drugs that predisposed residents to all included ADEs categories is common. Research is needed to support and evaluate safe care-home prescribing practices.