Drug interactions with oral anticoagulants in German nursing home residents: comparison between vitamin K antagonists and non-vitamin K antagonist oral anticoagulants based on two nested case–control studies

  • Kathrin JobskiEmail author
  • Falk Hoffmann
  • Stefan Herget-Rosenthal
  • Michael Dörks
Original Paper



Vitamin K antagonists (VKAs) are susceptible to drug–drug interactions. Non-VKA oral anticoagulants (NOACs) have a decreased sensitivity to pharmacokinetic interactions and might be therefore considered superior in patients treated with multiple drugs. The objective of this study was to compare the risk of serious bleeding associated with interacting drugs in German nursing home residents treated with VKA or NOAC.


Using claims data of new nursing home residents aged ≥ 65 years (2010–2014) we conducted separate nested case–control analyses within two cohorts of patients treated with VKA or NOAC, respectively. Cases were defined as patients hospitalized for serious bleeding. For each case, up to 20 controls were selected by risk-set sampling. Conditional logistic regression was used to obtain confounder-adjusted odds ratios (aORs) and 95% confidence intervals (CI) for the risk of bleeding associated with VKA or NOAC use and interacting drugs compared with the use of the respective oral anticoagulant alone.


Among 127,227 new nursing home residents, 16,804 patients received oral anticoagulation. Based on 372 cases and 7281 matched controls, the highest risk of bleeding in VKA users was observed for the concomitant use of antibiotics (aOR 3.00; CI 2.11–4.27) vs. VKA use alone, followed by non-steroidal anti-inflammatory drugs (1.66; 1.13–2.43). Among 243 NOAC cases and 4776 matched controls, elevated risks for bleeding were observed for the use of heparins (2.05; 1.25–3.36) and platelet inhibitors (1.92; 1.36–2.72).


Concomitant medication needs to be prescribed cautiously and monitored closely in nursing home residents treated with oral anticoagulants.

Graphic Abstract


Anticoagulants Drug interactions Risk of bleeding Nursing home residents 



The authors thank the DAK-Gesundheit for providing the data for this study.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Supplementary material

392_2019_1526_MOESM1_ESM.docx (66 kb)
Supplementary material 1 (DOCX 66 kb)


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Department of Health Services ResearchCarl von Ossietzky University OldenburgOldenburgGermany
  2. 2.Department of MedicineRotes Kreuz HospitalBremenGermany

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