Division of Clinical Drug Informatics, Kindai University Graduate School of Pharmacy, Higashi-osaka, Japan.
Maruzen Pharmacy, Osaka, Japan.
J Clin Pharm Ther. 2020 Oct;45(5):991-996. doi: 10.1111/jcpt.13122. Epub 2020 Jan 27.
Polypharmacy is associated with an increased risk of adverse drug reactions (ADRs) and drug interactions, decreased adherence to medication and increased medical cost. Recently, polypharmacy has become a major problem in medical care in Japan as a result of the increase in the ageing population. The purpose of this study was to investigate the current situation of polypharmacy and the association between polypharmacy and adverse events.
A retrospective data analysis was performed using two different real-world data from 2007 to 2015 in Japan. The Japanese Adverse Drug Event Report (JADER), a public spontaneous adverse drug reaction database constructed by the Pharmaceuticals and Medical Devices Agency (PMDA), and a large prescription database constructed by a database vendor (Japan Medical Information Research Institute, Inc Japan [JMIRI]) were analysed. Trends of polypharmacy during the study period were investigated.
The mean number of drugs per report in the JADER database and per prescription in the JMIRI databases during the study period ranged from 4.8 to 5.6 and 3.5 to 3.7, respectively. The mean number of drugs increased with age in both the JADER and JMIRI databases, and the peak of the mean number of drugs was at 80-89 years (5.74 drugs) in the JADER database and at 90-99 years (4.97 drugs) in the JMIRI database.
The number of drugs increased until age 90 years or more, even though adverse events are more likely to occur after the age of 80 in Japan. Therefore, polypharmacy in the elderly should be focused on the patients aged ≥80 years rather than patients aged ≥65 years from the viewpoint of the prevention of adverse events.
多种药物治疗与药物不良反应（ADR）和药物相互作用的风险增加、药物依从性降低以及医疗费用增加有关。最近，由于人口老龄化的增加，多种药物治疗在日本的医疗保健中已成为一个主要问题。本研究的目的是调查多种药物治疗的现状以及多种药物治疗与不良事件之间的关系。
使用来自日本 2007 年至 2015 年的两个不同真实世界数据进行回顾性数据分析。日本药品和医疗器械管理局（PMDA）构建的公共自发药物不良反应数据库日本药物不良反应报告（JADER）和数据库供应商（日本医药信息研究所，Inc Japan [JMIRI]）构建的大型处方数据库被分析。研究期间多种药物治疗的趋势也进行了调查。
JADER 数据库中每份报告的平均用药数和 JMIRI 数据库中每份处方的平均用药数在研究期间分别为 4.8 至 5.6 和 3.5 至 3.7。JADER 和 JMIRI 数据库中，平均用药数随年龄增加而增加，JADER 数据库中平均用药数的峰值在 80-89 岁（5.74 种药物），JMIRI 数据库中在 90-99 岁（4.97 种药物）。
即使在日本，80 岁以后发生不良反应的可能性更高，但药物的数量仍会增加到 90 岁或以上。因此，从预防不良事件的角度来看，应关注年龄≥80 岁的老年患者，而不是年龄≥65 岁的老年患者。
