Heparin for venous thromboembolism prophylaxis in patients with acute spinal cord injury: a systematic review and meta-analysis

Abstract

The objective of this study is to systematically review and estimate the effect of heparin for thromboprophylaxis in patients with acute spinal cord injury (SCI). We searched the PubMed database up to February 2013. Only randomized control trials (RCTs), quasi-RCTs, cohorts, case-control and cross-sectional studies were included. The incidence of venous thromboembolism (VTE) and major bleeding complication were recorded as the endpoints. The summary relative risks (RR) were calculated by meta-analysis. A total of 18 studies with 2578 patients were included. Four studies evaluated the effects of low-dose unfractionated heparin (LDUH) compared placebo or untreated. No significant differences were observed, with the summary RR 0.661 (95% confidence interval (CI) 0.365-1.199; Z=1.36, P=0.173) for VTE. Only one RCT compared fixed-dose LDUH with adjusted-dose LDUH, which showed lower VTE incidence but higher bleeding incidence for adjusted dose. Nine trials have compared LDUH with low-molecular-weight heparin (LMWH). No significant differences were observed for VTE with the summary RR 1.633 (95% CI 0.822-3.243; Z=1.40, P=0.162). But major bleeding was lower with LMWH (summary RR=2.034, 95% CI 1.018-4.063; Z=2.01, P=0.044). Three studies compared different LMWHs, which included one for enoxaparin versus tinzaparin and two for enoxaparin versus dalteparin. No significant differences were observed with the summary RR 0.694 (95% CI 0.336-1.434; Z=0.99, P=0.324) for VTE. Three studies compared different dose of LMWH. No differences were observed. Our meta-analysis showed that in patients with acute SCI, LDUH have no thromboprophylaxis effect compared with placebo or untreated; LMWH seems only can reduce bleeding incidence, but not prophylaxis thromboembolism compared with LDUH. Because of no good quality studies existed in this setting, well-designed RCTs are urgently needed.