Factors Associated with Multiple Medication Use in Different Age Groups

BACKGROUND: Multiple medicine use among elderly persons is likely to be the result of treatment regimens developed over a long period of time. By learning more about how multiple medication use develops, the quality of prescribing may be improved across the adult lifespan. OBJECTIVE: To describe patterns of multiple medicine use in the general Swedish population and its association with sociodemographic, lifestyle, and health status factors. METHODS: Data from a cross-sectional population health survey collected during 2001-2005 from 2816 randomly selected Swedish residents (age 30-75 y; response rate 76%) were analyzed. Multiple medicine use was restricted to prescription drugs and defined as the 75th percentile; that is, the 25% of the study group using the highest number of drugs per individual. RESULTS: Seventy-one percent of the respondents used some kind of drug, 51.5% used one or more prescription drug, 38.4% used one or more over-the-counter (OTC) medication, and 8.3% used one or more herbal preparation. The cutoff amounts defining multiple medicine use were: 2 or more medications for 30- to 49-year-olds, 3 or more for 50- to 64-year-olds, and 5 or more for 65- to 75-year-olds. No association between use of multiple medicines and use of OTC drugs or herbal preparations was found. When drugs were classified into therapeutic subgroups, 76.3% of those aged 30-49 years, 97.9% of those aged 50-64 years, and 100% of those aged 65-75 years were taking a unique combination of drugs. Multivariate analyses showed that diabetes and poor self-rated health were associated with multiple medicine use in all age cohorts. Female sex and hypertension were associated with multiple medicine use among those aged 30-49 and 50-64 years, current smoking among those aged 50-64 years, and obesity among those aged 65-75 years. CONCLUSIONS: Multiple medicine use was associated with morbidity and poor self-rated health across all age groups. The vast majority of users of multiple drugs are taking a unique combination of medications.