Management and evaluation of treatment adherence and effectiveness in chronic venous disorders: results of the international study VEIN Act Program Abstract Objective The aim of this study was to examine worldwide chronic venous disease (CVD) burden and evaluate effectiveness, adherence and satisfaction with conservative treatment. Materials and methods The VEIN Act Program (VAP) was an international, prospective, observational study that enrolled adult outpatients with lower-limb pain consulting for any CVD-related clinical presentation. Patients’ CVD symptoms, Clinical Etiological Anatomic Pathophysiologic (CEAP) classification, and symptom intensity were recorded. After prescribing conservative treatments, patients returned for a follow-up visit. Result A total of 567 physicians enrolled 7987 patients, 7397 of whom were included in the analysis. Patients were mainly female (79.3%), mean age was 54.0 ± 15.1 years and mean body mass index was 26.8 ± 4.8 kg/m2. CEAP clinical classifications were C0s (3.6%), C1 (19.4%), C2 (21.8%), C3 (32.0%) and C4–C6 (23.2%). Symptoms were reported by 89.6% of patients and were present across all CEAP classes. Mean intensity (10 cm visual analog scale) was > 5 cm for all symptoms. Only 30.7% of patients had previously consulted for leg problems, and 24.3% had previously received treatment. Conservative treatment alone was prescribed to 78.3% of patients, and in association with operative treatment in 21.6% of patients, and consisted mostly of venoactive drugs (VADs) [99.6%, mostly micronized purified flavonoid fraction] and compression therapy (63.4%) in combination with lifestyle changes such as weight loss. Adherence to prescribed duration was 65.2% for VADs, but only 29.1% wore compression therapy as prescribed. Symptom relief was high with VADs and compression therapy (> 96%), and the majority of patients were satisfied (94.1%). Conclusion Conservative treatments were beneficial across the spectrum of CVD, highlighting the importance of identifying patients early in the disease course.