Effect of ageing upon warfarin dose requirements: a longitudinal study.
This longitudinal study was designed to establish the rate of age-related change in warfarin dose requirements. Warfarin dosage was recorded retrospectively in 104 patients who had been stabilized on warfarin for a median period of 10 years (range 6-24 years) for prophylaxis of thromboembolic disease. There was a significant negative correlation between dosage and age at the start of therapy (p = 0.002, r = -0.30). Warfarin requirements fell over time, dosage difference being significantly correlated with age difference (p = 0.01, r = 0.25). Use of regression equation derived from these data suggests a 21% fall in warfarin requirements in this population over a 15-year period. The relationship between change in warfarin dose requirements and ageing established in this longitudinal study is in good agreement with that established by cross-sectional studies, suggesting that no major birth cohort effect is influencing requirements in our warfarin-treated population.
Wynne
H A
HA
Department of Medicine, University of Newcastle upon Tyne.
Kamali
F
F
Edwards
C
C
Long
A
A
Kelly
P
P
D000328:Adult; D000367:Age Factors; D000368:Aged; D000925:Anticoagulants / Q000008:administration & dosage* / Q000009:adverse effects; D004305:Dose-Response Relationship, Drug; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013923:Thromboembolism / Q000097:blood / Q000517:prevention & control*; D014859:Warfarin / Q000008:administration & dosage* / Q000493:pharmacokinetics
D000925:Anticoagulants; D014859:Warfarin