By Bianca Nogrady
People with varicose veins are at significantly higher risk of deep venous thrombosis (DVT), a recent study has found.
Writing in JAMA, researchers reported the results of a retrospective cohort study in 212,984 Taiwanese patients with varicose veins – but without a history of DVT, pulmonary embolism (PE) or peripheral artery disease (PAD) – and 212,984 controls.
Analysis of data from the national health insurance program showed that individuals with varicose veins had a greater than fivefold increased risk of DVT compared with propensity-matched controls, over approximately seven years of follow up.
The association was influenced by age and sex; the highest hazard ratio was seen among individuals aged 20 to 34 years, and it decreased with increasing age.
Varicose veins were also associated with a 73% increase in the hazard ratio for PE, which was similar regardless of age and sex, and a 72% increase in the hazard ratio for PAD. The association with PAD was higher in men than in women, and decreased with increasing age until 75 years.
The authors commented, however, that as this was an observational retrospective study, information on potential confounders such as smoking and obesity was not available and these may have played a role in the associations seen.
‘The magnitude of the association between varicose veins and PE and PAD was small, and therefore, it may more likely be due to residual or unmeasured confounding,’ they wrote.
Commenting on the findings, Sydney varicose veins surgeon Dr Mark Malouf said the common link between all these conditions was a rise in inflammatory markers.
‘This theme is very evident in venous meetings today, not only in patients with varicose veins but in those with thrombosis, and it is of course one of the pathophysiological mechanisms proposed for PAD as well,’ Dr Malouf told Cardiology Today.
He said the findings needed confirmation with further research, as the study had limitations in terms of possible nonhomogeneity between the groups, but they were thought provoking.
‘The take-home message for the clinician who is treating patients with varicose veins is to be aware of the hazard ratio figures suggested in this paper and to keep a clinical eye out for the DVT, PE and PAD conditions in these patients.’
JAMA 2018; 319: 807-817.