Responsiveness of the condition-specific Outcome measures for VAscular MAlformations (OVAMA) questionnaire to measure symptoms and appearance in patients with vascular malformations

Background Evidence-based guidelines for the treatment of vascular malformations (VMs) are not readily available, possibly due to the diversity in methods used to evaluate treatment efficacy in clinical research, complicating the aggregation and comparison of study results. The Outcome measures for VAscular MAlformations (OVAMA) questionnaire was developed to measure uniformly symptoms and appearance (i.e. condition-specific core outcome domains) in patients with VMs. However, the OVAMA questionnaire needs to be responsive to changes in these constructs in order to assess whether disease status has changed since treatment.Objectives To assess the responsiveness of the OVAMA questionnaire in patients with VMs.Methods In a prospective longitudinal study, patients completed the OVAMA questionnaire at baseline and at 8 weeks after treatment or a watchful waiting policy. Additionally, patients completed global rating of change (GRC) scales at follow-up. Responsiveness was evaluated following the criterion approach of testing predefined hypotheses about expected relationships between the OVAMA questionnaire and GRC scales measuring the same constructs. The OVAMA questionnaire was considered responsive if >= 75% of the hypotheses were confirmed.Results Between July 2020 and September 2022, 89 patients were recruited in a vascular anomaly centre in the Netherlands; 63 patients completed the questionnaires at baseline and follow-up. In total, 15 constructs of the OVAMA questionnaire were assessed for 5 hypotheses. Of these 75 hypotheses, 63 (84%) were confirmed, providing evidence that the OVAMA questionnaire is responsive to change.Conclusion Our study found convincing evidence that the OVAMA questionnaire is responsive to changes in symptoms and appearance in patients with VMs. In addition to determining a baseline for symptoms and appearance, the OVAMA questionnaire can now be used to evaluate the effect of treatment from a patient's perspective. The responsive OVAMA questionnaire allows for uniform evaluation and comparison of the effects of treatment on the condition-specific core outcome domains, tackling heterogeneity in outcome measurement and improving the clinical research of VMs. The Outcome measures for VAscular MAlformations (OVAMA) questionnaire was developed to measure uniformly symptoms and appearance (i.e. condition-specific core outcome domains) in patients with vascular malformations (VMs). This study was performed to evaluate the responsiveness of the OVAMA questionnaire following the criterion approach of testing predefined hypotheses about expected relationships between the OVAMA questionnaire and other outcome measurement instruments and showed that the OVAMA questionnaire is responsive to changes in symptoms and appearance in patients with VMs. The OVAMA questionnaire can now be used to evaluate the effect of treatment from the patient's perspective and to achieve uniformity in outcome reporting. Congenital vascular malformations (or 'VMs') are rare abnormalities of blood vessels present from birth. They lead to a range of symptoms and can affect a person's appearance. The aim of treatment is to reduce the impact of VMs.Studies have shown that patients and doctors find it important that a treatment's effect is measured in the same way worldwide. To help with this, a questionnaire called the 'OVAMA' was created. To assess the effects of treatment, the OVAMA questionnaire is designed to find changes in symptoms and appearance. It is completed by patients.This Dutch study aimed to find out if the OVAMA questionnaire can detect changes in symptoms and appearance in people with VMs. We asked people with VMs to answer the OVAMA questionnaire before and after treatment. They also answered another questionnaire called the global rating of change (or 'GRC') scales after treatment. We compared the changes found by the OVAMA questionnaire with those found by the GRC. Changes in the symptoms and appearance of VMs found by both questionnaires were similar.Our findings suggest that the OVAMA questionnaire could be used to test the effect of treatment, from a patient's point of view. Our study also showed how the effectiveness of treatments can be measured in the same way so that the results of different studies can be compared.