Anaemia as an independent key risk factor for major haemorrhage in patients treated with vitamin K antagonists: Results of the SCORE prospective cohort

Long-term risk of recurrent venous thromboembolism among patients receiving extended oral anticoagulant therapy for first unprovoked venous thromboembolism: A systematic review and meta-analysis

BACKGROUND

The long-term risk for recurrent venous thromboembolism (VTE) during extended anticoagulation for a first unprovoked VTE is uncertain.

OBJECTIVES

To determine the incidence of recurrent VTE during extended anticoagulation of up to 5 years in patients with a first unprovoked VTE.

METHODS

MEDLINE, EMBASE, and the Cochrane CENTRAL were searched to identify randomized trials and prospective cohort studies reporting recurrent VTE among patients with a first unprovoked VTE who were to receive anticoagulation for a minimum of six additional months after completing ≥3 months of initial treatment. Unpublished data on number of recurrent VTE and person-years, obtained from authors of included studies, were used to calculate study-level incidence rate, and random-effects meta-analysis was used to pool results.

RESULTS

Twenty-six studies and 15 603 patients were included in the analysis. During 11 631 person-years of follow-up, the incidence of recurrent VTE and fatal pulmonary embolism per 100 person-years was 1.41 (95% CI, 1.03-1.84) and 0.09 (0.04-0.16), with 5-year cumulative incidences of 7.1% (3.0%-13.2%) and 1.2% (0.4%-4.6%), respectively. The incidence of recurrent VTE was 1.08 (95% CI, 0.77-1.44) with direct oral anticoagulants and 1.55 (1.01-2.20) with vitamin K antagonists. The case-fatality rate of recurrent VTE was 4.9% (95% CI, 2.2%-8.7%).

CONCLUSIONS

In patients with a first unprovoked VTE, the long-term risk of recurrent VTE during extended anticoagulation is low but not negligible. Thus, clinicians and patients should be aware of this risk and take appropriate and timely action in case of suspicion of recurrent VTE. Estimates from this study can be used to advise patients on what to expect while receiving extended anticoagulation, and estimate the net clinical benefit of extended treatment to guide long-term management of unprovoked VTE.

Long-Term Risk for Major Bleeding During Extended Oral Anticoagulant Therapy for First Unprovoked Venous Thromboembolism : A Systematic Review and Meta-analysis

BACKGROUND

The long-term risk for major bleeding in patients receiving extended (beyond the initial 3 to 6 months) anticoagulant therapy for a first unprovoked venous thromboembolism (VTE) is uncertain.

PURPOSE

To determine the incidence of major bleeding during extended anticoagulation of up to 5 years among patients with a first unprovoked VTE, overall, and in clinically important subgroups.

DATA SOURCES

MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials from inception to 23 July 2021.

STUDY SELECTION

Randomized controlled trials (RCTs) and prospective cohort studies reporting major bleeding among patients with a first unprovoked VTE who were to receive oral anticoagulation for a minimum of 6 additional months after completing at least 3 months of initial anticoagulant treatment.

DATA EXTRACTION

Two reviewers independently abstracted data and assessed study quality. Unpublished data required for analyses were obtained from authors of included studies.

DATA SYNTHESIS

Among the 14 RCTs and 13 cohort studies included in the analysis, 9982 patients received a vitamin K antagonist (VKA) and 7220 received a direct oral anticoagulant (DOAC). The incidence of major bleeding per 100 person-years was 1.74 events (95% CI, 1.34 to 2.20 events) with VKAs and 1.12 events (CI, 0.72 to 1.62 events) with DOACs. The 5-year cumulative incidence of major bleeding with VKAs was 6.3% (CI, 3.6% to 10.0%). Among patients receiving either a VKA or a DOAC, the incidence of major bleeding was statistically significantly higher among those who were older than 65 years or had creatinine clearance less than 50 mL/min, a history of bleeding, concomitant use of antiplatelet therapy, or a hemoglobin level less than 100 g/L. The case-fatality rate of major bleeding was 8.3% (CI, 5.1% to 12.2%) with VKAs and 9.7% (CI, 3.2% to 19.2%) with DOACs.

LIMITATION

Data were insufficient to estimate incidence of major bleeding beyond 1 year of extended anticoagulation with DOACs.

CONCLUSION

In patients with a first unprovoked VTE, the long-term risks and consequences of anticoagulant-related major bleeding are considerable. This information will help inform patient prognosis and guide decision making about treatment duration for unprovoked VTE.

PRIMARY FUNDING SOURCE

Canadian Institutes of Health Research. (PROSPERO: CRD42019128597).

Anemia and bleeding in patients receiving anticoagulant therapy for venous thromboembolism: comment

Kuperman et al. found that patients with anemia had a higher risk of major bleeding (RR 2.84; 95% CI 2.52-3.39) in RIETE database. Anemia appeared to be an independent predictive factor for major bleeding [hazard ratio (HR) 1.95; 95% CI 1.72-2.20] in this registry. Unfortunately, selection bias due to enrolled patients does not allowed us to use these major results in ambulatory care. The aim of SCORE study was to refine bleeding risk estimation in French vitamin K antagonist (VKA) treated patients and to identifying one or several parameters of prognostic significance. We conducted a prospective, multi-center cohort study of 962 consecutive outpatients from private angiologic offices, clinics and hospitals enrolled in grenoble angiologic network for thromboembolic diseases between May 2009 and December 2010, followed during 1 year by their general practitioner. Main outcome was the occurrence of major bleeding or clinically non major relevant bleeding (CNMRB). Incidence rates major bleeding and CNMRB were 2.86 (95% CI 1.95-4.2) events per 100 patient-years and 12% (95% CI 9.89-14.11) respectively. Cox multivariate analyses showed that only anemia was strongly associated with a risk of major bleeding (HR 6.1; 95% CI 2.7-13.8; p = 0.001). Logistic regression analyses performed in CNMRB showed that anemia, prior gastro-intestinal bleeding and antiplatelet drug use were strongly associated with a risk of CNMRB at 1 year, respectively OR 2.53, 95% CI (1.4-4.56); p = 0.002, OR 3.32, 95% CI (1.51-7.31); p = 0.003 and OR 1.77, 95% CI (1.1-2.83); p = 0.017. These new data were consistent between major and CRNM bleeding in VKA treated patients. The key role of anemia should be confirmed in other prospective cohort studies, with different anticoagulants use such as direct oral anticoagulant in ambulatory care settings.