Validation of the Brazilian version of the VERITAS-Pro scale to assess adherence to prophylactic regimens in hemophilia

Abstract

Introduction: Prophylaxis is the treatment of choice for patients with severe hemophilia. Low adherence may limit the effectiveness of the prophylactic regimen, thereby compromising outcomes. Objective: The objective of this study was to validate the Brazilian version of the VERITAS-Pro prophylaxis adherence scale, originally an American questionnaire that can be answered by the individual responsible for prophylaxis as well as by an observer. Methods: The scale has 24 questions divided into six subscales: Routine, Dosage, Plan, Remember, Skip and Communicate. Participants were recruited at a blood center in southeastern Brazil for validation and reliability analyses. Validation measures included the results obtained using analog visual scales of adherence, interval between medication dispensed by the treatment center pharmacy and the percentage of recommended doses administered and infusions registered in the patients’ logs. Results: The study included 32 individuals responsible for prophylaxis and five observers. The internal consistency was very good for the VERITAS-Pro total score, excellent for the Remember, Skip and Communicate subscales, good for the Dosage subscale, and acceptable for the Routine and Plan subscales. Twelve participants answered the questionnaire on more than one occasion to evaluate reproducibility. The intraclass correlation coefficient was excellent. Regarding convergent validity, the VERITAS-Pro scores were moderately correlated with the global adherence scale and with infusion log records, but showed a weak correlation with pharmacy dispensation records. Conclusion: The Brazilian version of VERITAS-Pro is a valid and reliable instrument, enabling the understanding of specific factors related to non-adherence and allowing targeted interventions for proper treatment. Keywords: Hemophilia, Medication adherence, Questionnaire, Validation study