Purpose: To assess the prevalence of polypharmacy and frailty, to examine their association, and to establish their independent and combined effects on mortality in a sample of French old people.

Methods: This is a cross-sectional population study of people aged 70 years and over. A total of 2350 respondents were interviewed at home in 2008-2010. Frailty was defined as impairment in three domains or more among nutrition, energy, physical activity, strength, and mobility, in the absence of difficulties in basic activities of daily living. Mortality data were documented after a mean follow-up period of 2.6 years.

Results: Mean age of the population was 83.3 +/- 7.5 years, with 59.4% of women. Prevalence of frailty was 17.0%. Polypharmacy (5-9 drugs) was reported in 53.6% of the population, and excessive polypharmacy (10 drugs or more) in 13.8%. After adjustment for socio-demographic and health variables, polypharmacy and excessive polypharmacy were associated with frailty with odds ratio 1.77 [1.20-2.61] and 4.47 [2.37-8.42], respectively. Frailty (hazard ratio [HR] 2.56 [1.63-4.04]) and excessive polypharmacy (HR 1.83 [1.28-2.62]) were independent predictors of mortality. Compared with non-frail people without polypharmacy, frail people with excessive polypharmacy were six times more likely to die during the follow-up period (HR 6.30 [3.09-12.84]).

Conclusion: By showing the independent and combined effects of polypharmacy and frailty on mortality risk, this study should reinforce the awareness of clinicians with regard to these factors, rather prevalent in old people.