VERITAS-Pro: a new measure of adherence to prophylactic regimens in haemophilia.

Prophylactic treatment is recommended for severe haemophilia. Non-adherence to a prophylactic regimen can limit treatment effectiveness and compromise outcomes. The aim of this study is to validate a new prophylactic treatment adherence scale entitled Validated Hemophilia Regimen Treatment Adherence Scale--Prophylaxis (VERITAS-Pro), a self-/parent-report questionnaire consisting of 24 questions on six (four-item) subscales (Time, Dose, Plan, Remember, Skip, Communicate) that takes approximately 10 min to complete and is currently available in English only. Participants were recruited to complete the VERITAS-Pro for validation and reliability analysis; and observers were recruited for inter-rater reliability analysis. Validation measures included subjective adherence ratings from participants and providers and the total number of recommended infusions administered as obtained from infusion logs. Data were evaluated for the entire sample and for parent-report and self-report subsamples. The study sample included 67 males, 53 (79.1%) diagnosed with severe FVIII deficiency. Internal consistency for the total VERITAS-Pro score and all subscales was good to excellent; test-retest reliability correlations were very strong. Validation measures were strongly correlated with VERITAS-Pro scores. The VERITAS-Pro is a reliable and valid measure of adherence to prophylactic treatment of haemophilia. The VERITAS-Pro has greater utility than a global or informal rating of adherence because it represents a quantified and validated measure of adherence from the patient's perspective and it divides adherence into specific areas, allowing insight into particular issues underlying non-adherence. This tool may increase sensitivity to adherence problems and allow more targeted interventions to enhance adherence.