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

Abstract

Background: Although 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.

Objective: To 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.

Methods: The 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.

Results: The 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].

Conclusion: The 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.