Abstract No. 150 Development and validation of a health-related quality-of-life measure for vascular malformations: the PROVAM questionnaire

Abstract

Quality-of-life and patient-reported outcome measures have become a major focus of clinical and outcomes assessments. The purpose of this study was to develop a valid Patient Reported Outcome Measure for Vascular Malformation (“PROVAM”) questionnaire to assess health-related quality of life in patients with vascular malformations (VAMs) before and after treatment. We developed and validated PROVAM using a mixed-methods design during an IRB-approved, prospective clinical trial at a VAM clinic. The pilot instrument consisted of 30 items (26 Likert-type response scale, 4 free-response) across domains including pain, social and emotional well-being, functional impact, and treatment. Functional impact items were specific to VAM anatomic location (head and neck or torso and extremities). Two items were included in the test battery to assess questionnaire relevance and ease of understanding. The questionnaire was implemented in the clinical setting from July 2019 to February 2020 to obtain evidence for reliability and construct validity of items and scales. To evaluate reliability, internal consistency was measured using Cronbach’s alpha. Factor analysis, and convergent and discriminant validity testing were used to assess construct validity. Responsiveness was evaluated using patients with both pre- and post-treatment questionnaires, with the hypothesis that total score would decrease post-treatment. 108 patients with VAM (median age 18 years; 58% female) completed a total of 130 questionnaires. All subscales including pain, emotional and social well-being, and functional impact, had Cronbach’s alpha coefficients > = 0.79. These dimensions were confirmed by factor analysis (P< 0.001). 25 of 26 Likert-type response questions were shown to be valid with good convergent and discriminant construct validity. In a subset of patients who completed PROVAM pre- and post-treatment (median follow up 10-weeks; n = 13), there was a significant decrease in total score (P = 0.036). Participants found survey questions easy to understand (median score 5 [IQR 4-5] on 5-point Likert-type scale) and relevant (median score 4 [IQR 3-5]). Preliminary data support the reliability, validity, and responsiveness of the 30-item PROVAM instrument to measure health-related quality of life in patients with VAMs.