Prevalence of prescription and non-prescription polypharmacy by frailty and sex among middle-aged and older Canadians.

Background: Estimates of polypharmacy have primarily been derived from prescription claims, and less is known about the use of non-prescription medications (alone or in combination with prescription medications) across the frailty spectrum or by sex. Our objectives were to estimate the prevalence of polypharmacy (total, prescription, non-prescription, and concurrent prescription and non-prescription) overall, and by frailty, sex and broad age group.

Data: Canadian Health Measures Survey, Cycle 5, 2016 to 2017.

Methods: Among Canadians aged 40 to 79 years, all prescription and non-prescription medications used in the month prior to the survey were documented. Polypharmacy was defined as using five or more medications total (prescription and non-prescription), prescription only and non-prescription only. Concurrent prescription and non-prescription use was defined as two or more and three or more of each. Frailty was defined using a 31-item frailty index (FI) and categorized as non-frail (FI ≤ 0.1) and pre-frail or frail (FI > 0.1). Survey-weighted descriptive statistics were calculated overall and age standardized.

Results: We analyzed 2,039 respondents, representing 16,638,026 Canadians (mean age of 56.9 years; 51% women). Overall, 52.4% (95% confidence interval [CI] = 47.3 to 57.4) were defined as pre-frail or frail. Age-standardized estimates of total polypharmacy, prescription polypharmacy and concurrent prescription and non-prescription medication use were significantly higher among pre-frail or frail versus non-frail adults (e.g., total polypharmacy: 64.1% versus 31.8%, respectively). Polypharmacy with non-prescription medications was common overall (20.5% [95% CI = 16.1 to 25.8]) and greater among women, but did not differ significantly by frailty.

Interpretation: Polypharmacy and concurrent prescription and non-prescription medication use were common among Canadian adults, especially those who were pre-frail or frail. Our findings highlight the importance of considering non-prescribed medications when measuring the exposure to medications and the potential risk for adverse outcomes.