Factors associated with multiple medication use in different age groups

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.

To describe patterns of multiple medicine use in the general Swedish population and its association with sociodemographic, lifestyle, and health status factors.

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.

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.

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.