Patterns of drug use and factors associated with polypharmacy and excessive polypharmacy in elderly persons: results of the Kuopio 75+ study: a cross-sectional analysis.

backgroundAlthough the increasing use of drugs in elderly persons has raised many concerns in recent years, the process leading to polypharmacy (PP) and excessive polypharmacy (EPP) remains largely unknown.

objectiveTo describe the number and type of drugs used and to evaluate the role of different factors associated with PP (i.e. 6-9 drugs) and EPP (i.e. > or =10 drugs), with special reference to the number and type of medical diagnoses and symptoms, in a population of home-dwelling elderly persons aged > or =75 years.

methodsThe study was a cross-sectional analysis of a population-based cohort in 1998. The population consisted of home-dwelling elderly persons aged > or =75 years in the city of Kuopio, Finland. The data for the analysis were obtained from the Kuopio 75+ Study, which drew a random sample of 700 elderly residents aged > or =75 years living in the city of Kuopio from the population register. Of these, 601 attended a structured clinical examination and an interview carried out by a geriatrician and a trained nurse in 1998. For this analysis, all home-dwelling elderly participants (n = 523) were included. Study data were expressed as proportions and means with standard deviations. The factors associated with PP and EPP were examined by multinomial logistic regression.

resultsThe most commonly used drugs were cardiovascular drugs (97% in EPP, 94% in PP and 59% in non-PP group) and analgesics (89%, 76% and 54%), respectively. Use of psychotropics was markedly higher in the EPP group (77%) than in the PP (42%) and non-PP groups (20%). The mean number of drugs per diagnosis was 3.6 in the EPP group, 2.6 in the PP group and 1.6 in the non-PP group. Factors associated only with EPP were moderate self-reported health (odds ratio [OR] 2.05; 95% CI 1.08, 3.89), female gender (OR 2.43; 95% CI 1.27, 4.65) and age > or =85 years (OR 2.84; 95% CI 1.41, 5.72). Factors that were associated with both PP and EPP included poor self-reported health (PP: OR 2.15; 95% CI 1.01, 4.59 and EPP: OR 6.02; 95% CI 2.55, 14.20), diabetes mellitus (PP: OR 2.28; 95% CI 1.26, 4.15 and EPP: OR 2.07; 95% CI 1.03, 4.18), depression (PP: OR 2.13; 95% CI 1.16, 3.90 and EPP: OR 2.93; 95% CI 1.51, 5.66), pain (PP: OR 2.69; 95% CI 1.68, 4.30 and EPP: OR 2.74; 95% CI 1.56, 4.82), heart disease (PP: OR 2.51; 95% CI 1.54, 4.08 and EPP: OR 4.63; 95% CI 2.45, 8.74) and obstructive pulmonary disease (including asthma or chronic obstructive pulmonary disease) [PP: OR 2.79; 95% CI 1.24, 6.25 and EPP: OR 6.82; 95% CI 2.87, 16.20].

conclusionThe study indicates that the factors associated with PP and EPP are not uniform. Age > or =85 years, female gender and moderate self-reported health were factors associated only with EPP, while poor self-reported health and several specific disease states were associated with both PP and EPP. The high number of drugs per diagnosis observed in this study calls for a thorough assessment of the need for and outcomes associated with use of these drugs.