Hospitalized patients with isolated distal deep vein thrombosis: anticoagulation therapy or not?

Background: Isolated distal deep vein thrombosis (IDDVT), a disease frequently detected in hospitalized patients, can progress to proximal deep vein thrombosis (PDVT) and pulmonary embolism (PE). Here, we evaluated the effects of anticoagulation in hospitalized IDDVT patients.

Methods: We conducted a retrospective study in our hospital and enrolled hospitalized IDDVT patients diagnosed by compression ultrasonography (CUS) from January to December 2020. Participants were divided into anticoagulation (AC) and non-anticoagulation (non-AC) groups. After propensity score matching (PSM), multivariate Cox regression analyses were performed to assess whether anticoagulation was associated with PDVT/PE, and all-cause mortality.

Results: A total of 426 IDDVT inpatients with CUS follow-up were screened from 1502 distal DVT patients and finally enrolled. The median age was 67 years with 51.4% males and 15.5% cancer patients. The median follow-up was 11.6 months. There were 288 and 138 patients treated with or without anticoagulants, respectively. Patients in the non-AC group had less body mass index and more comorbidities. Patients in the AC group were treated with rivaroxaban or dabigatran (52.1%), low molecular weight heparin (42.7%), and warfarin (5.2%). The PSM generated 111 pairs of well-matched IDDVT patients with or without anticoagulation. The Kaplan-Meier analysis demonstrated that neither the incidence of PDVT/PE (5.4% vs. 2.7%, log-rank p = 0.313) nor all-cause mortality (27.9% vs. 18.9%, log-rank p = 0.098) was significant different between groups. Anticoagulation was not associated with PDVT/PE and all-cause mortality in the multivariable Cox regression analyses using the matched cohorts. The main risk factors for all-cause mortality were age, malignancy history, BMI, sepsis, heart failure, and white blood cell (WBC) count.

Conclusions: In hospitalized IDDVT patients, the thrombosis extension rate to PDVT/PE was low. Anticoagulation did not reduce the incidence of thrombosis extension of IDDVT and was not associated with all-cause mortality.