This study was aimed to investigate the prevalence of venous thromboembolism in patients with chronic venous disease and the impact of some intrinsic and extrinsic risk factors.

A retrospective study on 641 outpatients (489 women) with primary chronic venous disease (C₀–C₆). The prevalence of venous thromboembolism was evaluated according to sex, age, BMI, the presence of ≥1 first-degree siblings diagnosed with venous thromboembolism, CEAP clinical class, smoking and the use of hormone therapy.

Venous thromboembolism episodes occurred in 32 patients (5%) with no gender predominance (OR 1.49, 95% CI = 0.90–2.45; p = 0.146). There was no increased RR of venous thromboembolism in the age group 46–69 years compared with patients aged ≤45 years (p = 0.350). In persons aged ≥70 years, the risk of venous thromboembolism was 3.2 times higher than in patients aged 46–69 years and 4.78 times higher than in patients aged ≤45 years. The risk of venous thromboembolism rose very significantly in obese compared with normostenic patients (p = 0.002). There were significantly more venous thromboembolism episodes in patients with chronic venous insufficiency (55.3%) than patients with varicose veins (44.7%) (p < 0.001). A family history of venous thromboembolism (p = 0.12), smoking (p = 0.905) and hormone therapy (p = 0.326) were not associated with increased risk of venous thromboembolism. Smoking was a risk factor in obese patients (p = 0.033), but the combination of obesity, smoking, estrogens in women did not increase the risk of venous thromboembolism.

The 5% prevalence of venous thromboembolism episodes in patients was comparable with the prevalence of venous thromboembolism in the general European population. Age ≥70 years and obesity were strongly associated with an occurrence of venous thromboembolism. Obese patients with chronic venous disease were at higher risk for venous thromboembolism than obese people in the general population. A family history of venous thromboembolism, smoking and estrogens alone or in combination were not revealed as significant risk factors.