Incidence of varicose veins, chronic venous insufficiency and venous reflux in the general population and associated risk factors: the Edinburgh Vein Study follow up
Robertson, Lindsay Anne
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Chronic venous disease (CVD) is a common problem in the western world, causes considerable morbidity and has a substantial impact on the health care system in terms of cost of treatment. Most epidemiological research has focussed on the prevalence of varicose veins and ulceration. As such, evidence on the incidence and risk factors is limited. The aim of this study was to measure the incidence of C2 varicose veins, C3-C6 chronic venous insufficiency (CVI) and venous reflux ≥ 0.5 seconds duration in an adult population, and to investigate risk factors associated with the development of these conditions. The Edinburgh Vein Study was a prospective cohort study in which 1,566 men and women aged 18-64 years randomly sampled from the general population underwent an examination comprising clinical and photographic classification of CVD, duplex scanning of the deep and superficial systems of both legs, and completed a questionnaire on lifestyle and medical history. After a 13 year period, invitations were sent to the 1456 survivors to attend a follow up examination. In total, 880 participated in the follow up study, giving a response rate of 60.4%. The overall incidence of C2 varicose veins was 18.2% (95% CI 15.2-21.6), equivalent to an annual incidence rate of 1.4% (95% CI 1.1-1.7). There were no gender differences (p=0.78). Age was associated with the development of new C2 varicose veins the 13 year incidence rose from 9.8% in those aged 18-34 years to 25.7% in those aged 55-64 years (p<0.001). New cases of C3-C6 CVI developed in 9.2% (95% CI 7.0-11.9) of the study sample over 13 years, an annual incidence rate of 0.7% (95% CI 0.5-0.9). There were no gender differences: the 13 year incidence was 10.7% (95% CI 7.2-15.5) and 8.1% (95% CI 5.7-11.6) in men and women respectively (p=0.32). The incidence increased consistently with age, from 2.1% in those aged under 35 years to 17.1% in those aged over 55 years (p<0.001). Of all C3-C6 conditions, C3 corona phlebectatica had the highest incidence (5.3%, 95% CI 3.7-7.5). C5-C6 venous ulceration had the lowest incidence, affecting only 0.5% (95% CI 0.2-1.6) of the study sample over the 13 years. Overall, 12.7% of participants developed new venous reflux ≥0.5 seconds duration from baseline to follow up. The 13 year incidence of superficial, deep and combined venous reflux was 8.8%, 2.6% and 1.3% respectively. Neither age nor sex were associated with the incidence of venous reflux (p>0.05). The highest incidence of reflux was in the great saphenous vein in the lower third of the thigh (4.2%, 95% CI 2.4-7.1). Venous reflux at baseline was associated with the development of new C2 varicose veins at follow up: the incidence creased linearly in those with no reflux, deep, superficial and combined reflux respectively (p<0.001). Family history of venous disease was a significant risk factor for C2 varicose veins (age and sex-adjusted OR 1.7, 95% CI 1.1-2.7) while obesity was associated with the development of CVI (age and sex adjusted OR 4.5 (95% CI 3.3-6.9). Pregnancy appeared to be associated with the development of varicose veins but the association was not statistically significant due to small numbers. No risk factor was associated with the development of venous reflux. The Edinburgh Vein Study is one of a few cohort studies to report the incidence of C2 varicose veins, C3-C6 CVI and venous reflux ≥0.5 seconds duration, and investigate risk factors associated with these conditions. While the results on incidence are consistent with the limited evidence from other studies, the exact effect of risk factors remains unknown. Genetic studies would help clarify whether CVD is an inherited or acquired condition. For other risk factors, results of this study could be combined with other population-based studies in a meta-analysis. The overall estimate of effect would identify the most important risk factors associated with the development of CVD and venous reflux. Finally the natural history and progression of CVD needs to be assessed. The Edinburgh Vein Follow Up Study has examined this relationship and results will help to identify those most likely to progress to more severe disease and, in turn, those who will benefit most from treatment. Appropriate, clinically proven, effective and cost-effective treatments can then be administered in an attempt to reduce the burden of CVD.