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.