Validation of International Warfarin Pharmacogenetics Consortium (IWPC) Algorithm in Elderly Patients With Comorbidity

Prospective Validation of IWPC Pharmacogenetic Algorithm for Estimating the Appropriate Initial Dose of Warfarin in Elderly People (65 or Older) With Heart Valves Prostheses or Non Valvular Atrial Fibrillation and Comorbidity

The purpose of this study is to validate the International Warfarin Pharmacogenetics Consortium (IWPC) algorithm in a prospective cohort of elderly people (65 years or older) with heart valves and/or nonvalvular atrial fibrillation (AF) and at least one comorbid condition, and to assess the algorithm's prognostic relevance.

Inclusion Criteria:

• Age ≥ 65 years
• Patients who initiate warfarin because of non valvular atrial fibrillation or heart valve replacement
• At least one comorbid condition
• At least two other drugs regularly assumed over and above warfarin

Exclusion Criteria:

• Presence of systemic coagulopathies
• Presence of malignancies needing chemotherapy
• Inability or refusal to give informed consent