Content Validity for the VVSymQ® Instrument: A New Patient-Reported Outcome Measure for the Assessment of Varicose Veins Symptoms

BACKGROUND Varicose veins are common and can impact patients' quality of life, but consensus regarding the evaluation of varicose vein symptoms is lacking and existing measures have limitations. OBJECTIVE This research aimed to develop and establish the content validity of a new electronic patient-reported outcome (PRO) measure, the VVSymQ® instrument, to assess symptoms of superficial venous insufficiency (varicose veins) in clinical trials. METHODS The development of the VVSymQ® instrument began with qualitative interviews with patients based on the symptom domain of the VEINES-QOL/Sym, an existing PRO instrument for chronic venous disorders of the leg. Three phases of qualitative research were conducted to examine the relevance and importance of the symptoms to patients with varicose veins, and the patients' ability to understand and use the VVSymQ® instrument. The development included evaluating questions that had 1-week and 24-h recall periods, and paper and electronic versions of the new instrument. RESULTS Five symptoms (heaviness, achiness, swelling, throbbing, and itching [HASTI™]) were consistently reported by patients across all sources of qualitative data. The final version of the VVSymQ® instrument queries patients on the HASTI™ symptoms using a 24-h recall period and a 6-point duration-based response scale ranging from "None of the time" to "All of the time," and is administered daily via an electronic diary. Cognitive interviews demonstrated varicose vein patients' understanding of and their ability to use the final version of the VVSymQ® instrument. CONCLUSION Content validity was established for the VVSymQ® instrument, which assesses the five HASTI™ symptoms of varicose veins daily via an electronic diary and has promise for use in research and practice.