Introduction: The risk of stroke associated with atrial fibrillation (AF) is greatest in the elderly. However, in this age group, systemic anticoagulation (SA) is often underused due to fear of bleeding complications. This fear persists inspite of the introduction of newer anticoagulants. Ironically, in this age group, warfarin may be the safer anticoagulant despite their greater sensitivity to the drug and greater risk of complications. Dosing algorithms for W have been developed to reduce the risks of SA, the effectives in the elderly is not known. We had previously demonstrated that W dosing based on ACCP recommendations (ADR) was effective. The effect of age on the effectiveness and safety of this regimen is the subject of this study.
Methods: From our anticoagulation practice we then identified 61 consecutive patients with chronic AF whose medical regimen was otherwise stable. Their INR and clinical histories were then abstracted. They were then stratified according to age into 45-60, 60-79, and greater than 80 years. The times in therapeutic (TTR), as well as time in sub therapeutic (SUB) and supra therapeutic (SUP) ranges for each group were then calculated and compared using ANOVA.
Results: Majority of patients were drawn from those over 60 years of age. Using ADR the rates of effective anticoagulation was comparable among the different age groups. Likewise, safety as reflected in the time SUB or SUP was the same for all groups.
Conclusions: A warfarin dosing regimen based on current ACCP guidelines results in similar rates of effective anticoagulation in all age groups, including octogenarians. The safety profile was likewise comparable across the different age groups.