BACKGROUND: The risk of recurrence after a venous thromboembolism (VTE) related to estrogen-containing contraceptives is a key driver to guide anticoagulant treatment decisions.
OBJECTIVE: To estimate the incidence rate of recurrent VTE after discontinuation of anticoagulant treatment in women with a first episode of VTE related to estrogen-containing contraceptives.
METHODS: Embase, MEDLINE, and the CENTRAL were searched from 1 January 2008 to 27 May 2021 for prospective and retrospective studies reporting on recurrence after a first VTE related to estrogen-containing contraceptives. Risk of bias was assessed using QUIPS tool. Recurrence rates per 100 patient-years were pooled using Knapp-Hartung random-effects meta-analysis. Incidence rates were reported separately based on study follow-up duration (=1 year, 1-5 years, and >5 years) and for several subgroups.
RESULTS: A total of 4,120 studies were identified, of which 14 were included. The pooled recurrence rate was 1.57 (95%-CI: 1.10-2.23; I2 = 82%) per 100 patient-years. Recurrence rates per 100 patient-years were 2.73 (95%-CI: 0.00-3643; I2 = 80%) for studies with =1 year follow-up, 1.35 (95%-CI: 0.68-2.68; I2 = 44%) for studies with 1-5 years follow-up, and 1.42 (95%-CI: 0.84-2.42; I2 = 78%) for studies with >5 years follow-up.
CONCLUSION: Among women with VTE associated with estrogen-containing contraceptives, the risk of recurrence after stopping anticoagulation is low, which favors short-term anticoagulation. Large prospective studies on VTE recurrence rates and risk factors after stopping short-term anticoagulants are needed.
This is a worthwhile review to share, but I do think the results need to be interpreted with caution. The study discussion leans toward a suggestion that the lower risk for recurrent VTE is solely because the index VTE was OCP associated (thus, stop OCP and low recurrent VTE). The median age of the population was young (mainly in 30s) and presumably all female, which are populations known to have lower recurrent VTE, most not requiring long-term anticoagulation even when fully 'unprovoked'. The question that is not answered: is if the risk of recurrent VTE for OCP-associated VTE similar to otherwise matched unprovoked VTE. That is, the review doesn't address the risk for recurrent VTE in an obese female with OCP-associated VTE but also severe PTS and positive 6-month D-dimer (high HERDOO2).