# The incidence of early recurrent venous thromboembolism: a systematic review and meta-analysis

## TL;DR

This study finds that stopping anticoagulation briefly after 3 months is safe, as early recurrence of blood clots is rare.

## Contribution

The study provides the first meta-analysis of early VTE recurrence after discontinuing anticoagulation, showing a low risk.

## Key findings

- Early recurrence of VTE occurred in 1.04% of patients after stopping anticoagulation.
- Unprovoked VTE was associated with a 2.6-fold higher recurrence risk compared to provoked VTE.
- No fatal recurrences were reported, suggesting that stopping anticoagulation briefly is safe.

## Abstract

Patients with venous thromboembolism (VTE) receive anticoagulation for at least 3 months. To evaluate recurrence risk thereafter, some strategies include D-dimer testing after discontinuing anticoagulation, which raises concern about early recurrence.

To assess the incidence of recurrent VTE within 30 days after stopping anticoagulation.

We conducted a systematic review of EMBASE, CENTRAL, and MEDLINE to identify controlled trials and cohort studies of adult noncancer patients with deep vein thrombosis of the leg and/or pulmonary embolism treated with anticoagulants for ≥3 months. The primary outcome was symptomatic VTE within 30 days. The risk of bias was assessed using a modified version of the Newcastle-Ottawa Scale. Pooled recurrence rates were calculated using fixed random-effects meta-analyses.

Of 42 studies, 24 (57%) provided data, encompassing 11,407 patients. Early recurrence occurred in 115 patients (1.01%), with a pooled incidence of 1.04% (95% CI, 0.8%-1.4%). Men had a risk similar to that of women (risk ratio, 1.2; 95% CI, 0.6-2.3; P = .7). Unprovoked VTE was associated with a 2.6-fold increase in risk (95% CI, 1.4-4.6; P < .001) compared with provoked VTE. Patients with deep vein thrombosis at presentation had a similar risk of recurrence compared with those with an incident pulmonary embolism (risk ratio, 0.6; 95% CI: 0.3-1.2; P = .1). Findings regarding age were inconsistent. None of the recurrences was fatal. The overall risk of bias was low.

The incidence of early VTE recurrence after stopping anticoagulation is low. Temporarily discontinuing therapy to assess recurrence risk, therefore, appears safe and may aid in guiding treatment duration.

•Off-therapy D-dimer tests after VTE raise concern about early recurrence.•We performed a systematic review and meta-analysis of studies of VTE patients anticoagulated for ≥3 months.•Early recurrence was rare (1.04%). Stopping anticoagulation briefly appears safe.•Off-therapy assessment may help guide treatment duration.

Off-therapy D-dimer tests after VTE raise concern about early recurrence.

We performed a systematic review and meta-analysis of studies of VTE patients anticoagulated for ≥3 months.

Early recurrence was rare (1.04%). Stopping anticoagulation briefly appears safe.

Off-therapy assessment may help guide treatment duration.