Rationale, design, and methodology of the observational INSIGHTS-SVT study on the current state of care and outcomes of patients with superficial vein thrombosis

Abstract Objective Superficial vein thrombosis (SVT) is a common disease in clinical practice. In terms of pathophysiology and outcomes, the condition is related to venous thromboembolism, bearing a potential for severe thromboembolic complications if it is not treated adequately. A wide range of treatment approaches (including oral and injectable anticoagulants, pain medication, nondrug therapy including compression therapy, and no treatment at all) are applied in clinical practice, but there is sparse information about selection of patients for therapies, current treatment pathways, and drug use as well as outcomes. The INvestigating SIGnificant Health TrendS in the management of Superficial Vein Thrombosis (INSIGHTS-SVT) study aims to close this gap by collecting representative data on the current treatment of SVT. Methods The observational prospective study of about 1200 patients is carried out by up to 120 clinical and office-based physicians who regularly treat patients with SVT and are capable of conducting appropriate compression ultrasound diagnostics, such as vascular physicians, phlebologists, internists, vascular surgeons, and general practitioners. Patients are eligible for inclusion if they have ultrasound-confirmed acute, isolated SVT of the lower extremities. Documentation about the characteristics of the patients, diagnostics, comorbidities, and medical and nonmedical treatment is collected at baseline, at 10 ± 3 days or at approximately 45 days (depending on treatment), at approximately 3 months, and at approximately 12 months. Patients are requested to fill in quality of life questionnaires (on pain, Venous Insufficiency Epidemiological and Economic Study on Quality of Life/Symptoms [VEINES-QOL/Sym], EuroQol-5 Dimension 5-Level [EQ-5D-5L]) at baseline and at approximately 3 months. Interventions are not stipulated by the trial protocol. Results The primary efficacy outcome is the incidence of venous thromboembolism at 3 months; the primary safety outcome is the combined incidence of major and clinically relevant bleeding events at 3 months. As quality measures, plausibility checks at data entry, queries based on statistical analyses that focus on outliers and distribution of values, monitoring visits, and adjudication procedures will be applied. Conclusions This large study is expected to provide a comprehensive picture of patients with SVT under clinical practice conditions in Germany.