Protocol for a longitudinal cohort study: determination of risk factors for the development of first venous leg ulcer in people with chronic venous insufficiency, the VEINS (venous insufficiency in South Florida) cohort

Abstract

IntroductionChronic venous insufficiency (CVI) affects up to one-third of the adult population yet venous leg ulcers (VLU), a significant complication of CVI, only affect 1%–2% of adults in the USA. Why some develop VLU and others do not is unclear. VLU have a significant impact on quality of life and are extremely costly and difficult to treat. Moreover, VLU prevalence is increasing, doubling in the last 20 years. In order to characterise the differences between people with CVI and those who ultimately develop VLU, we aim to set up the unique venous insufficiency in South Florida cohort.Methods and analysisSubjects will be recruited from the University of Miami Hospital and Clinic’s vascular laboratory database, which began in July 2011. Any adult age 18–95 who has had venous reflux detected on duplex ultrasound of the lower extremities is included. Approximately 2500 patients are already in the database that meet these criteria, with an estimated 2500 additional potential subjects to be recruited from the vascular laboratory database over the next 5 years. Subjects with a history of VLU prior to the duplex study date will be excluded. Data will be collected via review of the Doppler study report, patient phone interview and review of the electronic medical record. Subjects will be contacted for follow-up every 3 months for at least 5 years until the study endpoint, development of first VLU (fVLU), is reached. In order to estimate the time from reflux documentation to fVLU, Kaplan-Meier survival curves will be constructed. Cox proportional hazard regression models will be constructed to investigate possible risk factors.Ethics and disseminationThis study is approved by the University of Miami’s Institutional Review Board. We hope to present the results of this study to the scientific community at conferences and in peer-reviewed journals.