Incidence and Effects of Polypharmacy on Clinical Outcome among Patients Aged 80+: A Five-Year Follow-Up Study

Objectives Polypharmacy is a problem of growing interest in geriatrics with the increase in drug consumption in recent years, is defined according to the WHO criteria as the, "concurrent use of five or more different prescription medication". We investigated the clinical characteristics of polypharmacy and identified the effects of polypharmacy on clinical outcome among patients aged 80+ admitted to Chinese PLA general hospital. Methods Older men aged >= 80 years (n = 1562) were included in this study. The included participants attended a structured clinical examination and an interview carried out by a geriatrician and trained nurses. A follow-up survey in 2014 was carried out on survivors in the same way as in 2009. The clinical outcome measured were adverse drug reactions, falls, frailty, disability, cognitive impairment, mortality. The association between polypharmacy and clinical outcome was assessed by logistic regression. Results The mean (range) age of the included participants was 85.2 (80-104) years. Medication exposure was reported by 100% of the population. Mean number of medications reported in this population was 9.56 +/- 5.68. The prevalence of polypharmacy (>= 6 medications) in the present study was 70%. At the time of the follow-up survey, an increase in the number of taken medicines had occurred among half of the survivors. The risk of different outcomes in relation to number of medications rises significantly, the odds ratios were 1.21 (95% confidence interval [CI] 1.17-1.28) for adverse drug reactions, 1.18 (95% CI 1.10-1.26) for falls, 1.16 (95% CI 1.09-1.24) for disability, and 1.19 (95% CI 1.12-1.23) for mortality. There was no association between increasing number of medications and cognitive impairment. Conclusions Our study demonstrates that polypharmacy is very common in the very old patients, and observed that number of medications was a factor associated with difference clinical outcome independently of the age, type of medications prescribed and accompanied comorbidities.