Control of warfarin therapy in the elderly.

Eighty patients over 65 years old with satisfactory coagulation control with Warfarin were selected and analysed to determine factors predictive of dose. Age followed by urea were the important predictors. Albumin, globulin, sex, weight and T3 uptake were not significant factors. It is concluded that care should be taken when Warfarin is given to older patients, particularly those with high blood-urea levels.