Need of more frequent International Normalized Ratio monitoring in elderly patients on long-term anticoagulant therapy after influenza vaccination

Daniela Poli, L. Chiarugi, M. Capanni, E. Antonucci, R. Abbate, G. F. Gensini, D. Prisco

Research output: Contribution to journalArticle

Abstract

Previous findings suggest the safety of influenza vaccination for patients on oral anticoagulant therapy (OAT). However, some studies reported a moderate reduction or increase of the anticoagulation. We assessed the effect of influenza vaccination on anticoagulation levels. Seventy-three patients on stable long-term OAT were recruited. Patients were compared with a control group of 72 patients observed during the same period. No differences in the anticoagulation levels were found in patients and in controls during the 3 months before and after the vaccination. However, in patients older than 70 years we observed a reduction of anticoagulation intensity achieved in the month after the vaccination, with a prolonged time spent below the therapeutic range (10% before and 27% after, P = 0.001), and this behaviour was still observed 3 months after vaccination. Influenza vaccination is safe in patients on OAT, but it is associated with a slight reduction in warfarin effect in the elderly, suggesting the need of more frequent International Normalized Ratio monitoring after vaccination in these subjects.

Original languageEnglish
Pages (from-to)297-300
Number of pages4
JournalBlood Coagulation and Fibrinolysis
Volume13
Issue number4
DOIs
Publication statusPublished - Jun 2002

Keywords

  • Elderly patients
  • Influenza vaccination
  • Oral anticoagulant therapy

ASJC Scopus subject areas

  • Hematology

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