Analysis of warfarin therapy in pediatric patients: A prospective cohort study of 319 patients

This study details warfarin use in a large pediatric population followed in a central anticoagulation clinic. A prospective, consecutive cohort of non selected children were studied. Patients were divided into groups by age, t arget international normalized ratio (INR) range, disease, medications, and vitamin K supplemented enteral nutrition use. Groups were analyzed on mult iple aspects of warfarin therapy using multivariate methods. A total of 319 patients received 352 warfarin courses representing 391 treatment years. A ge independently influenced all aspects of therapy. When compared with all older children, the less than or equal to 1 year of age group required incr eased warfarin doses, longer overlap with heparin, longer time to achieve t arget INR ranges, more frequent INR testing and dose adjustments, and fewer INR values in the target range, Although significantly different than chil dren less than or equal to 1 year, children 1 to 6 years of age showed the same findings when compared with 7- to 18-year-olds. Fontan patients requir ed 25% decreased dosage as compared with other congenital heart disease pat ients. Children on corticosteroids had less INRs in the target range and ch ildren on phenobarbital/carbamazepine required increased maintenance dosage s of warfarin, Also, patients receiving enteral nutrition required increase d dosages of warfarin, Serious bleeding occurred in 2 children (0.5% per pa tient year). Recurrent thromboembolic events (TEs) occurred in 8 children. Two children had recurrences while receiving warfarin (1.3% per patient yea r). This study outlines the profound effect of age and relative complexity of clinical management of warfarin therapy in children. (C) 1999 by The Ame rican Society of Hematology.