Responsiveness of the Patient-Reported Outcome Measure for Vascular Malformation Questionnaire in Patients with Low-Flow Vascular Malformations

Purpose: To assess the responsiveness, defined as the ability to detect change in a patient's health or function, of the Patient-Reported Outcome Measure for Vascular Malformation (PROVAM) questionnaire in a cohort of patients with low-flow vascular malformations (VMs). Materials and Methods: PROVAM was previously developed to assess symptoms, functional limitations, and social/emotional effects experienced by patients with VMs. This is a prospective cohort study of 56 patients with venous and lymphatic VMs who completed at least 2 PROVAM questionnaires, of whom 43 had undergone treatment with sclerotherapy in the interim between questionnaires. External responsiveness was assessed using a receiver operating characteristic (ROC) curve to ascertain whether a change in the total PROVAM score predicts whether patients reported symptom improvement and by correlating the change in the total PROVAM score and change in symptoms reported during clinic visit. Internal responsiveness was evaluated using Wilcoxon signed rank test, Cohen d effect size (ESp), and standard response mean difference (SRM). Results: The total PROVAM score demonstrated excellent discrimination for symptom improvement with an area under the ROC curve of 0.856. There was a statistically significant, moderate positive correlation between the change in the total PROVAM score and the change in patient symptoms as determined from clinical visits (Spearman correlation coefficient [r_s] = 0.67, P < .001). The total PROVAM score and all subdomain scores improved significantly after treatment (all P < .05). ESp and SRM were 0.80 and 0.83, respectively. Conclusions: PROVAM is responsive to improvement after treatment and may be useful to assess health-related quality of life in patients treated for VMs.