Drugs & Therapy Perspectives

, Volume 34, Issue 7, pp 322–334 | Cite as

Evaluation of potential prescribing errors in patients with polypharmacy: a method to improve medication safety in ambulatory care

  • Friederike LaidigEmail author
  • Marcus May
  • Julia Brinkmann
  • Nils Schneider
  • Dirk O. Stichtenoth
Original Research Article



Medication errors in ambulatory care are frequent and present an increased risk for adverse drug events. Polypharmacy is particularly susceptible to prescribing errors. Estimating the potential risk of such errors may lead to measures that increase patient safety.


The aim of this study was to evaluate potential prescribing errors that were identified by pharmacotherapy experts in patients receiving polypharmacy in ambulatory care.


Medication analyses of 400 patients participating in a German health insurance project and receiving polypharmacy (defined as five or more drugs) were examined. Potential prescribing errors identified were categorized into 8 main categories and 33 sub-criteria. The reliability and severity of these errors were evaluated using the Delphi method to estimate the potential risk, and a risk score was calculated. The number of responses from attending physicians receiving the results of the medication analyses was assessed.


On average, patients took 13.4 ± standard deviation (SD) 3.6 drugs regularly. In total, 2937 potential prescribing errors were identified in 400 medical records, primarily for the criteria “indication” (29%) and “interaction” (28%). Maximum severity was found for the criterion “contraindication” (sk = 2). The risk score was highest for the criterion “interaction” (rk = 3.1) and lowest for “dosage” (rk = 1.5). A total of 17% of physicians contacted replied.


A large number of potential prescribing errors were found. Medication analysis by experts combined with pharmacological consultation with the attending physicians were a valuable tool to detect potential prescribing errors and may help to improve medication safety.



The study was conducted based on “Arzneimittel sicher anwenden”, a project launched by KKH, a German statutory health insurance. DOS coordinated the project together with Lutz Herbarth (PhD, KKH). MM, JB, FL and DOS carried out the medication analyses. FL, MM, JB, NS and DOS assessed the reliability of the underlying data. MM, JB, Christoph Schröder (docent, Institute of Clinical Pharmacology, MHH), Jens Tank (professor, Institute of Clinical Pharmacology, MHH), Stefan Engeli (professor, Institute of Clinical Pharmacology, MHH) and DOS rated the severity of the PPEs as members of the Delphi method.

Author contributions

FL was responsible for the study concept, acquired the data, carried out the statistical analysis, interpreted the data and drafted the manuscript. All authors contributed to critical revision of the manuscript and read and approved the final manuscript.

Compliance with ethical standards

Ethics approval

The study was approved by the Ethical Review Committee of Hannover Medical School (no: 1637-2012) according to German regulations. All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Formal consent is not required for this type of study. This article does not contain any studies with animals performed by any of the authors.

Consent to participate

Informed consent from participants was not required as the retrospective study design did not affect the healthcare of included patients. All personal data were subjected to pseudonymization, and retracing was not possible without the pseudonym key. All data were analysed anonymously.


This study received no external funding.

Conflict of interest

Friederike Laidig, Marcus May, Julia Brinkmann, Nils Schneider and Dirk O. Stichtenoth have no conflicts of interest.

Supplementary material

40267_2018_507_MOESM1_ESM.pdf (121 kb)
Supplementary material 1 (PDF 120 kb)


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Copyright information

© Springer International Publishing AG, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Institute of Clinical PharmacologyHannover Medical SchoolHannoverGermany
  2. 2.Clinical Research Center HannoverHannover Medical SchoolHannoverGermany
  3. 3.Institute of General PracticeHannover Medical SchoolHannoverGermany
  4. 4.Kaufmännische Krankenkasse - KKHHannoverGermany

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