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Original Paper

Intensity of Long-Term Treatment with Warfarin Is Influenced by Seasonal Variations

Salobir B. · Šabovič M. · Peternel P.

Author affiliations

Department of Vascular Diseases, University Medical Centre, Ljubljana, Slovenia

Corresponding Author

Mišo Šabovič, MD, PhD

Department of Vascular Diseases

University Medical Centre Ljubljana

Riharjeva 24, 1000 Ljubljana (Slovenia)

Tel. +386 1 283 3500, Fax +386 1 283 3155, E-Mail miso.sabovic@trnovo.kclj.si

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Pathophysiol Haemost Thromb 2002;32:151–154

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In a prospective study, which lasted 1 year and was performed on a large cohort of 800 patients treated at an outpatient anticoagulant clinic, we investigated possible seasonal variations in the intensity of the effect of warfarin treatment. For every season – winter, spring, summer and autumn – the mean prothrombin time reported as an international normalised ratio (INR) and the percentages of INR below 2.0 and above 4.0 were calculated. Significant seasonal variations in mean INR measurements were found, with the lowest values in summer and the highest values in autumn (F = 14.2, p < 0.0001). In addition, a trend toward a higher percentage of INR below 2.0 in summer and above 4.0 in autumn was observed. No significant differences were found between older (>65 years) and younger (<65 years) patients, although there was a trend toward more pronounced variations in younger patients. Consideration of seasonal variations might result in more accurate and safe guidance of warfarin treatment.

© 2002 S. Karger AG, Basel

Article / Publication Details

First-Page Preview
Abstract of Original Paper

Received: May 09, 2002
Accepted: August 13, 2002
Published online: December 10, 2009
Issue release date: May 2003

Number of Print Pages: 4
Number of Figures: 2
Number of Tables: 2

ISSN: 1424-8832 (Print)
eISSN: 1424-8840 (Online)

For additional information: http://www.karger.com/PHT

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