Inappropriateness of Medication Prescriptions to Elderly Patients in the Primary Care Setting: A Systematic Review Dedan Opondo 1 *, Saied Eslami 1 , Stefan Visscher 2 , Sophia E. de Rooij 3 , Robert Verheij 2 , Joke C. Korevaar 2 , Ameen Abu-Hanna 1 1 Department of Medical Informatics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands, 2 Netherlands Institute for Health Services Research (NIVEL), Utrecht, The Netherlands, 3 Department of Geriatrics, Academic Medical Center, University of Amsterdam, The Netherlands Abstract Background: Inappropriate medication prescription is a common cause of preventable adverse drug events among elderly persons in the primary care setting. Objective: The aim of this systematic review is to quantify the extent of inappropriate prescription to elderly persons in the primary care setting. Methods: We systematically searched Ovid-Medline and Ovid-EMBASE from 1950 and 1980 respectively to March 2012. Two independent reviewers screened and selected primary studies published in English that measured (in)appropriate medication prescription among elderly persons (.65 years) in the primary care setting. We extracted data sources, instruments for assessing medication prescription appropriateness, and the rate of inappropriate medication prescriptions. We grouped the reported individual medications according to the Anatomical Therapeutic and Chemical (ATC) classification and compared the median rate of inappropriate medication prescription and its range within each therapeutic class. Results: We included 19 studies, 14 of which used the Beers criteria as the instrument for assessing appropriateness of prescriptions. The median rate of inappropriate medication prescriptions (IMP) was 20.5% [IQR 18.1 to 25.6%.]. Medications with largest median rate of inappropriate medication prescriptions were propoxyphene 4.52(0.10–23.30)%, doxazosin 3.96 (0.32 15.70)%, diphenhydramine 3.30(0.02–4.40)% and amitriptiline 3.20 (0.05–20.5)% in a decreasing order of IMP rate. Available studies described unequal sets of medications and different measurement tools to estimate the overall prevalence of inappropriate prescription. Conclusions: Approximately one in five prescriptions to elderly persons in primary care is inappropropriate despite the attention that has been directed to quality of prescription. Diphenhydramine and amitriptiline are the most common inappropriately prescribed medications with high risk adverse events while propoxyphene and doxazoxin are the most commonly prescribed medications with low risk adverse events. These medications are good candidates for being targeted for improvement e.g. by computerized clinical decision support. Citation: Opondo D, Eslami S, Visscher S, de Rooij SE, Verheij R, et al. (2012) Inappropriateness of Medication Prescriptions to Elderly Patients in the Primary Care Setting: A Systematic Review. PLoS ONE 7(8): e43617. doi:10.1371/journal.pone.0043617 Editor: Colin Simpson, The University of Edinburgh, United Kingdom Received January 3, 2012; Accepted July 23, 2012; Published August 22, 2012 Copyright: ß 2012 Opondo et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: These authors have no support or funding to report. Competing Interests: The authors have declared that no competing interests exist. * E-mail: d.o.opondo@amc.uva.nl Introduction The elderly population is increasing, resulting in a concomitant increase in chronic diseases and functional impairment [1]. Moreover many of the elderly persons suffer from co-morbid conditions and disabilities that necessitate multiple medications or polypharmacy [2,3]. Adverse drug events are common in ambulatory care settings [4] and up to 35% of high risk older outpatients develop preventable adverse drug events [5]. One cause of preventable adverse drug events is the prescription of inappropriate medica- tions. Inappropriate medication prescription (IMP) has been defined as the prescription(s) that introduce(s) a significant risk of an adverse drug related event when there is evidence for an equally or more effective alternative medication [6]. It can also be described as the failure to achieve the optimal quality of medication use [7]. IMP has been classified as underprescribing, misprescribing or overprescribing [8]. Several factors increase the risk of IMP to elderly persons, including physiological changes like reduction in renal and hepatic function, both of which are detrimental of drug metabolism and disabilities like visual and cognitive decline. Aparasu et al. [9] and Gallagher et al. [10] reviewed, in 2000 and 2006 respectively, the incidence of IMP in elderly persons. Both reviews included studies with elderly persons in any healthcare setting from community dwelling elders to nursing PLOS ONE | www.plosone.org 1 August 2012 | Volume 7 | Issue 8 | e43617