The influence of Anemia on clinical outcomes in venous thromboembolism: Results from GARFIELD-VTE

Abstract Introduction Clinical characteristics and outcomes of venous thromboembolism (VTE) patients with concomitant anemia are unclear. This study compares baseline characteristics, treatment patterns, and 24-month outcomes in patients with and without anemia within GARFIELD-VTE. Materials and methods GARFIELD-VTE ( ClinicalTrials.gov : NCT02155491 ) is a global, prospective, non-interventional registry of real-world treatment practices. Of the 10,679 patients enrolled in GARFIELD-VTE, 7698 were eligible for analysis. Primary outcomes were all-cause mortality, recurrent VTE, and major bleeding in VTE patients with or without concomitant anemia over 24-months after diagnosis. Event rates and 95% confidence intervals were estimated using Poisson regression. Adjusted hazard ratios were calculated using Cox proportional hazard models. Results Distribution of VTE events in 2771 patients with anemia and 4927 without anemia was similar (deep-vein thrombosis alone: 61·1% vs. 55·9%, pulmonary embolism ± deep vein thrombosis: 38·9% vs. 44·0%, respectively). Patients with anemia were older (62.6 year vs. 58.9 years) than those without. At baseline, VTE risk factors that were more common in patients with anemia included hospitalization (22·0% vs. 6·8%), surgery (19·2% vs. 8·2%), cancer (20·1% vs. 5·6%) and acute medical illness (8·3% vs. 4·2%). Patients with anemia were more likely to receive parenteral anticoagulation therapy alone than those without anemia (26·6% vs. 11·7%) and less likely to receive a direct oral anticoagulant (38·5% vs. 53·5%). During 24-months of follow-up, patients with anemia had a higher risk (adjusted hazard ratio [95% confidence interval]) of all-cause mortality (1·84 [1·56–2·18]), major bleeding (2·83 [2·14–3·75]). Among anemia patients, the risk of all-cause mortality and major bleeding remained higher in patients with severe anemia than in those with mild/moderate anemia, all-cause mortality: HR 1·43 [95% CI: 1·21–1·77]; major bleeding: HR 2·08 [95% CI: 1·52–2·86]). Conclusions VTE patients with concomitant anemia have a higher risk of adverse clinical outcomes compared with those without anemia. Further optimization of anticoagulation therapy for VTE patients with anemia is warranted.