TY - JOUR
T1 - Polypharmacy, aging and potential drug-drug interactions in outpatients in Taiwan
T2 - A retrospective computerized screening study
AU - Lin, Chen Fang
AU - Wang, Chun Yu
AU - Bai, Chyi Huey
N1 - Funding Information:
The authors have no conflicts of interest that are relevant to the content of this paper. This study was supported financially by the Shin Kong Wu Ho-Su Memorial Hospital. We thank Mei-Ling Shu, Dr Swu-Jane Lin and Dr Churn-Shiouh Gau for providing advice on the study and Lucy Yun-Ju Pan for proof-reading the manuscript.
Copyright:
Copyright 2011 Elsevier B.V., All rights reserved.
PY - 2011
Y1 - 2011
N2 - Background: Polypharmacy is common in outpatients and has been identified as a major risk factor for drug-drug interactions (DDIs), which are an important cause of adverse drug reactions. There has been a rapid increase in the number of elderly patients worldwide. However, there have been few studies quantifying the impact of both patient age and the number of concomitant drugs prescribed on the probability of potential DDIs per person in general outpatients. Objective: To assess the extent to which polypharmacy and aging are associated with potential DDIs in outpatients at a medical centre in Taiwan. Methods: The medications of 81650 outpatients who visited a medical centre in Taiwan between January 2004 and March 2004 were retrospectively screened for potential DDIs using a computerized drug-interaction program. The main inclusion criteria were a minimum of two drug prescriptions and duration of use of 14 or more days. We also analysed the DDI pattern, which included severity, level of documentation and onset of potential DDIs, and assessed the impact of the number of drugs prescribed and of aging on the prevalence of potential DDIs per person. Results: The prevalence of potential DDIs was 25.6% (20902 of 81650). The mean±SD age of the 20902 patients with potential DDIs was 57.5±16.5 years, and 47.6% of these patients were male. The mean±SD number of prescribed drugs in patients with potential DDIs was 5.8±2.4, and 67.7% of these patients were prescribed more than four drugs. The majority (55.7%) of DDIs were of the C2 pattern (severity: moderate; documentation: probable). The prevalence of potential DDIs increased in a linear mode with increasing age (p<0.001) and with the number of drugs prescribed (p<0.001); furthermore, in addition to being independently associated with potential DDIs, these two factors interacted to increase the risk further. Conclusions: This study showed that approximately one-quarter of 81650 outpatients who visited a medical centre in Taiwan over a period of 3 months in 2004 had potential DDIs. We observed independent increases in potential DDIs per person in association with aging and increasing number of prescribed drugs. Furthermore, a significant interaction between these two factors was observed: the effect of aging on the prevalence of potential DDIs increased as the number of prescribed drugs increased. Potential DDIs in outpatients can be reduced by minimizing the number of drugs prescribed following careful consideration of both their benefits and risks, particularly in the aging population.
AB - Background: Polypharmacy is common in outpatients and has been identified as a major risk factor for drug-drug interactions (DDIs), which are an important cause of adverse drug reactions. There has been a rapid increase in the number of elderly patients worldwide. However, there have been few studies quantifying the impact of both patient age and the number of concomitant drugs prescribed on the probability of potential DDIs per person in general outpatients. Objective: To assess the extent to which polypharmacy and aging are associated with potential DDIs in outpatients at a medical centre in Taiwan. Methods: The medications of 81650 outpatients who visited a medical centre in Taiwan between January 2004 and March 2004 were retrospectively screened for potential DDIs using a computerized drug-interaction program. The main inclusion criteria were a minimum of two drug prescriptions and duration of use of 14 or more days. We also analysed the DDI pattern, which included severity, level of documentation and onset of potential DDIs, and assessed the impact of the number of drugs prescribed and of aging on the prevalence of potential DDIs per person. Results: The prevalence of potential DDIs was 25.6% (20902 of 81650). The mean±SD age of the 20902 patients with potential DDIs was 57.5±16.5 years, and 47.6% of these patients were male. The mean±SD number of prescribed drugs in patients with potential DDIs was 5.8±2.4, and 67.7% of these patients were prescribed more than four drugs. The majority (55.7%) of DDIs were of the C2 pattern (severity: moderate; documentation: probable). The prevalence of potential DDIs increased in a linear mode with increasing age (p<0.001) and with the number of drugs prescribed (p<0.001); furthermore, in addition to being independently associated with potential DDIs, these two factors interacted to increase the risk further. Conclusions: This study showed that approximately one-quarter of 81650 outpatients who visited a medical centre in Taiwan over a period of 3 months in 2004 had potential DDIs. We observed independent increases in potential DDIs per person in association with aging and increasing number of prescribed drugs. Furthermore, a significant interaction between these two factors was observed: the effect of aging on the prevalence of potential DDIs increased as the number of prescribed drugs increased. Potential DDIs in outpatients can be reduced by minimizing the number of drugs prescribed following careful consideration of both their benefits and risks, particularly in the aging population.
KW - Drug-utilisation
KW - Elderly
KW - Prescribing
UR - http://www.scopus.com/inward/record.url?scp=79951929592&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=79951929592&partnerID=8YFLogxK
U2 - 10.2165/11586870-000000000-00000
DO - 10.2165/11586870-000000000-00000
M3 - Article
C2 - 21250763
AN - SCOPUS:79951929592
SN - 1170-229X
VL - 28
SP - 219
EP - 225
JO - Drugs and Aging
JF - Drugs and Aging
IS - 3
ER -