Objective: To determine the prevalence of inappropriate medication use among hospitalized older adults and to identify predictors of this use.
Methods: A total of 5734 patients (mean age 79 years) admitted to geriatric and internal medicine wards participating in the study in 1995 and 1997 were included in this analysis. Inappropriate medication use was defined on the basis of the criteria published by Beers in 1997. Only medications used during hospital stay were considered for the present study.
Results: During hospital stay, 837 (14.6%) patients received one or more medications classified as inappropriate based on Beers criteria. Ticlopidine ( n=346; 6.0% of the study sample) was the most frequently used medication among those in Beers' list, followed by digoxin ( n=174; 3.0%) and amytriptyline ( n=113; 2.0%). The multivariate analysis showed that age [75-84 years vs 65-74 years, odds ratio (OR) 0.85, 95% confidence interval (CI) 0.71-1.00; >or=85 years vs 65-74 years, OR 0.58, 95% CI 0.46-0.73], cognitive impairment (OR 0.77, 95% CI 0.64-0.94), Charlson co-morbidity index (>or=2 vs 0-1, OR 1.20, 95% CI 1.02-1.40) and overall number of medications used during hospital stay (5-8 medications vs <5 medications, OR 2.20, 95% CI 1.72-2.82; >or=9 medications vs <5 medications, OR 3.68, 95% CI 2.86-4.73) were significantly associated with use of inappropriate medications.
Conclusions: Inappropriate medication use was common among hospitalized older adults. The most important determinant of risk of receiving an inappropriate medication was the number of drugs being taken. Older age and cognitive impairment were associated with a reduced likelihood of using an inappropriate medication.