Polypharmacy: a prevalence study in the Lumiar and Queluz Health Centres

Abstract

Objectives: To study the prevalence of polymedication and the use of natural products in adults and the elderly. Study type: Cross-sectional observational study. Setting: Lumiar (Lisbon) and Queluz (Sintra) Health Centres. Population: Patients older than 40 registered at the two health centres. Methods: A random sample of 583 patients was drawn from a population of 37,434. The sample was stratified according to gender and age (40-64 years; 65 and older). Variables studied were age, gender, education, profession, professional status, chronic use of medicines, use of natural products and health status self-perception. Pearsons hypotheses test was used, with the help of Statview statistical package. Results: 571 patients (55.7% females) were interviewed by telephone. Mean age was 58,2±11,1. Average consumption of drugs for more than three months was 2,2±0,1 for the complete sample. The elderly were taking, on average, 3,9±0,2 drugs. The prevalence of simultaneous use of two to four drugs (minor polymedication) was 30.8% in the total sample. Five or more drugs (major polymedication) were present in 17.2% of the population. Both minor (39.6%) and major (37.1%) polymedication were significatively higher in the elderly population (p<0.001), as well as the prevalence of major polymedication in females (21,1%; p<0.005). Prevalence of consumption of natural products was 28.3%. Health status self-perception was mostly considered «reasonable» or «good», being worse in the elderly and in women (p<0.001). Conclusion: High prevalences of polymedication were found, specially among the elderly and women. Taking into account the possible interactions between drugs and between these and natural products, the general practitioner must find preventive and interventional strategies to reduce polymedication.