Heart failure and risk of venous thromboembolism: a systematic review and meta-analysis

Background Venous thromboembolism is a major global health problem that is often secondary to other clinical situations. Many studies have investigated the association between venous thromboembolism and heart failure, but have yielded inconsistent findings. We aimed to quantify the absolute and relative risks (RR) for venous thromboembolism in patients with heart failure after hospital admission. We also assessed rates of venous thromboembolism in patients in different settings. Methods In this systematic review and meta-analysis, we searched for studies investigating the risk of venous thromboembolism in patients in hospital with heart failure. We searched for studies published between Jan 1, 1955, and March 31, 2015, in PubMed, Embase, Evidence-Based Medicine Reviews, Allied and Complementary Medicine Database, Ovid HealthSTAR, Global Health, Ovid Nursing Database, Web of Science, CINAHL Plus, ProQuest Central, Conference Papers Index, BIOSIS Previews, and ClinicalTrials.gov. All cohort studies and subgroup analyses of randomised controlled trials (RCTs) were eligible for inclusion if they reported venous thromboembolism rates (number of events per follow-up period) or RR estimates. We extracted data from published reports and contacted the corresponding authors of records with insufficient quantitative data. RRs and 95% CIs were pooled using a random-effects model. This study is registered with PROSPERO, number CRD42014015504. Findings Of 8673 records identified, we included 71 studies with data from 88 cohorts in our analysis, with 59 cohorts included in the assessment of venous thromboembolism rates and 46 cohorts included in the meta-analysis of heart failure and risk of venous thromboembolism. Venous thromboembolism rates varied widely in patients in hospital with heart failure from different settings. The overall median symptomatic venous thromboembolism rate was 2.48% (IQR 0.84-5.61); rates was were 3.73% (1.05-7.31) for patients who did not receive thromboprophylaxis and 1.47% (0.64-3.54) for those who did. Overall, patients with heart failure in hospital had an RR of 1.51 (1 .36-1.68) for venous thromboembolism. The overall I-2 statistic was 96.1% and there was no evidence of publication bias (Egger's test, p=0.46). Interpretation Heart failure is a common independent risk factor for venous thromboembolism. Thromboprophylaxis should be considered in clinical practice for high-risk patients.