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The risk of overanticoagulation in patients with heart failure on coumarin anticoagulants
Author(s) -
Visser Loes E.,
Bleumink Gysèle S.,
Trienekens Paul H.,
Vulto Arnold G.,
Hofman Albert,
Stricker Bruno H. Ch.
Publication year - 2004
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1111/j.1365-2141.2004.05162.x
Subject(s) - acenocoumarol , medicine , heart failure , phenprocoumon , risk factor , cohort , population , anticoagulant , epidemiology , cohort study , cardiology , warfarin , surgery , atrial fibrillation , environmental health
Summary Heart failure has been identified as a risk factor for increased coumarin anticoagulant responsiveness in several small‐scale experiments. Epidemiological studies quantifying the risk of overanticoagulation by heart failure in a non‐selected population on coumarins are scarce. Therefore, we investigated whether patients with heart failure have an increased risk of overanticoagulation and determined the effect of incidental heart failure on coumarin dose requirements. A cohort study of all patients was performed from an outpatient anticoagulation clinic treated with acenocoumarol or phenprocoumon between 1 January 1990 and 1 January 2000. All cohort members were followed until the first occurrence of an international normalized ratio (INR) ≥6·0, the last INR assessment, death, loss to follow‐up, or end of the study period. Of the 1077 patients in the cohort, 396 developed an INR ≥6·0. The risk of overanticoagulation was 1·66 [95% confidence interval (CI): 1·33–2·07] for cases of prevalent heart failure and 1·91 (95%CI: 1·31–2·79) for incidental cases. The decrease in dose requirements in patients with incidental heart failure showed a significant trend from the fifth INR measurement preceding the date of incidental heart failure to the third measurement after this date. Heart failure is an independent risk factor for overanticoagulation. Therefore, patients with heart failure should be closely monitored to prevent potential bleeding complications.