Background and aims: Sex-specific differences exist for the initial presentation of acute venous thromboembolism (VTE): men are more likely to present with proximal deep vein thrombosis (DVT) in the lower limbs (versus pulmonary embolism [PE] or isolated distal DVT [IDDVT]) than women. We studied in detail the influence of sex, age, and VTE risk factors on the initial presentation of IDDVT versus proximal DVT.
Methods: A total of 24,911 patients with a first episode of objectively diagnosed acute symptomatic lower-limb DVT (without symptomatic PE) were enrolled in RIETE (years 2000-2017) and included in the present analysis.
Results: A total of 4266 (17.1%) patients had IDDVT. No trend for more IDDVT diagnoses was observed over time. Women aged 40-69 had a higher proportion of IDDVT, especially between 40 and 49 years (+6.7%; 95CI +3.7%; +9.9%), whereas men had more often proximal DVT. The presenting location of first acute DVT depended on sex, age, and the prevalence and type of VTE risk factors. Recent surgery was independently associated with a diagnosis of IDDVT in both women and men, whereas active cancer and pregnancy were associated with proximal DVT.
Conclusions: The interaction between age and VTE risk factors influences the presenting location (distal versus proximal) of the first acute lower-limb DVT observed in women and men. Our observations extend to IDDVT the concept that different clinical manifestations of acute VTE may not fully share the same pathophysiological mechanisms: this contributes to explain sex-specific prognostic differences.
Keywords: Deep vein thrombosis; Distal DVT; Epidemiology; Provoking risk factors; Sex; Venous thromboembolism.
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