Evaluation of Patient and Physician Reported Reasons for Switching Factor VIII Replacement Therapies

Inclusion Criteria: Inclusion criteria for patients/caregivers in the Patient/Caregiver Study: * Patients with hemophilia A (≥ 18 years of age) or caregivers of children with hemophilia A (≥12-\<18 years of age) * Group 1: Hemophilia A patients/caregivers who have switched to FVIII products with improved half-life for the treatment of hemophilia A during the eligibility period. These patients can also include those who have switched back from FVIII products with improved half-life to conventional FVIII replacement therapy within the Data Collection Period * Group 2: Hemophilia A patients/caregivers who are considering switching to FVIII products with improved half-life within 12 months of the Start of the Documentation period and have been prescribed prophylaxis regimen of at least 2x/week * Able to understand, read, write and speak English * Provide electronic informed consent * Able to access the Internet for at least 20 minutes per day during the Data Collection Period Inclusion criteria for physicians: * At least 60% of time spent in direct patient care * Board-certified or eligible with a Specialty in Hematology or Hematology-Oncology * Physicians with a specialty in Hematology-Oncology must have at least 10% of their practice dedicated to treatment of hemophilia * A minimum of 2 years' experience treating hemophilia A patients Inclusion criteria for patients in the physician chart study: * Hemophilia A patients age 12 year and over * Prior treatment with one of the following FVIII replacement products: Adynovate, Afstyla, Eloctate, or Kovaltry * Patients that have 12 months of medical chart data available; 6 months on conventional therapy and 6 months after switching to FVIII products with improved half-life. Exclusion Criteria: Exclusion criteria for patients/caregivers in the Patient/Caregiver Study: \- Hemophilia A patient initiated FVIII products with improved half-life for the treatment at time of diagnosis with hemophilia A. Exclusion criteria for physicians: \- Unwilling to comply with the study protocol