Exploring Sources of Variability in Individual Pharmacokinetics of Factor VIII and IX Concentrates in Hemophilia in the Web Accessible Population Pharmacokinetics Service - Hemophilia (WAPPS-Hemo) Database

Innovation and expected results: As the classical PK approach typically requires 11 samples, which can be a burden to the patient, specific subgroups of individuals are often excluded from analysis-including children, elderly and critical care patients. As WAPPS-Hemo is the largest database of individual PK data, a large subgroup of pediatric patients and patients with inhibitors are available for investigation, allowing for analysis of variability in previously unavailable groups. Determining predictors of variability within patient outcome will allow us to improve the current models used to estimate individual PK, resulting in better individual care and use of resources.

Eligibility criteria: All valid data in the WAPPS-Hemo database will be used. All factor concentrates will be included. All available covariates will be analyzed.

Patients: Individuals with hemophilia A or B, any severity, who are registered on WAPPS-Hemo and for whom infusion and/or PK data are available. Both adult and pediatric patients will be included. Patients with history of inhibitors will be included as a separate subgroup.

Available covariates: age, sex, weight, height, dose and type of factor administered (as total and IU/kg), blood group, baseline factor level, positive history of inhibitors, hematocrit, hemoglobin, serum creatinine and laboratory methods used to measure factor VIII and factor IX.

Design: retrospective data analysis