Psychometric Evaluation of a New Patient-Reported Outcome (PRO) Symptom Diary for Varicose Veins: VVSymQ® Instrument

Abstract

Objective: To evaluate the psychometric properties of the VVSymQ® instrument, a new 5-item patient-reported outcome (PRO) measure for symptoms of varicose veins. Method: The VVSymQ® electronic daily diary was administered to outpatients who received routine treatment for varicose veins (N = 40). Compliance with diary administration and item score variability, reliability, construct validity, sensitivity to change, and clinically meaningful change were evaluated. Results: Patients completed >97 % of scheduled diary assessments (at screening, baseline, and week 8). The VVSymQ® instrument captured patients’ pre-treatment symptoms (all VVSymQ® symptoms were endorsed by ≥75 % of patients at baseline), and the change post-treatment (mean change in score −6.1), with a large Cohen effect size (1.6). Test–retest reliability was high (intraclass correlation coefficient 0.96); internal consistency was good (Cronbach’s alpha ≥0.76; baseline, week 8). VVSymQ® scores were more strongly associated with PRO scores that reflect symptoms and symptom impact (the Venous Insufficiency Epidemiological and Economic Study—Quality of Life/Symptoms [VEINES-QOL/Sym] instrument and the Chronic Venous Insufficiency Quality-of-Life Questionnaire [CIVIQ-20]) than with PRO scores that reflect appearance (the Patient Self-Assessment of Appearance of Visible Varicose Veins [PA-V3]) or clinician-reported outcome scores (the Clinical–Etiology–Anatomy–Pathophysiology [CEAP] Classification of Venous Disorders and Venous Clinical Severity Score [VCSS]), demonstrating construct validity. Patients reporting that symptoms were “moderately” or “much improved” on the Patient Global Impression of Change (PGIC) anchor (i.e., >97 % of patients) had mean improvements of −6.3 VVSymQ® points, while a cumulative distribution curve showed that 50 % of patients improved by ≥−5.8 points; thus, a score change of approximately −6 demonstrated a clinically meaningful change in this study. The clinically meaningful change in the VVSymQ® score was greater in patients with a greater baseline VVSymQ® symptom burden, and the VVSymQ® instrument captured clinically meaningful treatment benefit even in patients with a low baseline symptom burden. Conclusion: The 5-item VVSymQ® instrument is a brief, psychometrically sound, useful tool for evaluating patient-reported varicose veins symptoms.