-
1.
The role of low molecular weight heparin on recurrent pregnancy loss: A systematic review and meta-analysis.
Jiang, F, Hu, X, Jiang, K, Pi, H, He, Q, Chen, X
Taiwanese journal of obstetrics & gynecology. 2021;(1):1-8
Abstract
To assess the roles of the low molecular weight heparin (LMWH) on recurrent pregnancy loss (RPL). The relevant studies of all randomized controlled trials (RCTs) were retrieved, and the systematic evaluation was conducted. PubMed, Embase, and Cochrane library databases were searched by using keywords, including low-molecular-weight heparin or LMWH, and recurrent miscarriage or recurrent pregnancy loss in pregnant women from their earliest data to February 2020. Two investigators independently evaluated eligibility. Risk ratios (RRs) and their corresponding 95% confidence interval (CI) were determined. To pool the results, this meta-analysis was performed using random-effect model due to the high heterogeneity among these eight studies. A total of eight RCTs involving 1854 participants were included in the meta-analysis involving 963 patients with RPL who were prescribed LMWH (enoxaparin, tinzaparin, or dalteparin) alone and 891 patients who were treated with no LMWH interventions (placebo, folic acid or non-treatment) were compared. Pooled data from the remaining eight RCTs showed the differences between intervention groups and control groups. Compared with control groups, LMWH had significantly improved live births (RR,1.19; 95%CI, 1.03 to 1.38; P = 0.02), and reduced miscarriage rates (RR, 0.62; 95%CI, 0.43 to 0.91; P = 0.01). The study suggested that LMWH could improve the live births and reduce the miscarriage rates of RPL. Therefore, LMWH might be a good treatment choice for women with unexplained PRL.
-
2.
Early detection of the existence or absence of the treatment effect: A cumulative meta-analysis.
Laporte, S, Chapelle, C, Trone, JC, Bertoletti, L, Girard, P, Meyer, G, Safieddine, M, Cucherat, M, Ollier, E, Mismetti, P, et al
Journal of clinical epidemiology. 2020;:24-33
Abstract
OBJECTIVES An unexpected promising effect of low molecular weight heparins (LMWHs) on survival in patients with cancer was observed in early trials in post hoc subgroup analyses but not found in more recent trials. To highlight a possible regression over time toward the lack of the antitumoral effect of LMWHs, we performed a cumulative meta-analysis of survival data from randomized controlled trials (RCTs). STUDY DESIGN AND SETTING Medical databases were searched to identify RCTs comparing, in patients with cancer, LMWHs with placebo or no treatment in patients free of venous thromboembolism (VTE), or to vitamin K antagonists in patients who experienced an acute VTE in overall survival. The cumulative hazard ratio (HR) was estimated after each study inclusion in chronological order. RESULTS Twenty-three studies (12,970 patients) were included. The cumulative meta-analysis of the earlier trials showed a significant improvement in overall survival with LMWHs. This apparent benefit then gradually regressed over time toward an absence of the effect of LMWHs on survival (HR: 0.98 [95% confidence interval, 0.93; 1.03]). CONCLUSION Despite supportive experimental data and early clinical findings, the promising antitumoral effect of LMWHs in patients with cancer gradually vanished over time toward a lack of impact on overall survival. This result suggests 'p-hacking' and selective reporting of the positive results from post hoc subgroup analyses in the early studies.
-
3.
Anticoagulation for the Treatment of Cancer-Associated Thrombosis: A Systematic Review and Network Meta-Analysis of Randomized Trials.
Sobieraj, DM, Baker, WL, Smith, E, Sasiela, K, Trexler, SE, Kim, O, Coleman, CI
Clinical and applied thrombosis/hemostasis : official journal of the International Academy of Clinical and Applied Thrombosis/Hemostasis. 2018;(9_suppl):182S-187S
Abstract
To perform a systematic review and network meta-analysis evaluating the efficacy and safety of low-molecular-weight heparins (LMWHs), vitamin K antagonists (VKAs), and direct-acting oral anticoagulants (DOACs) for the treatment of cancer-associated thrombosis (CAT). We searched MEDLINE, Cochrane Central Register of Controlled Trials, and conference abstracts through March 2018. Randomized controlled trials (RCTs) enrolling adults with CAT comparing 2 or more full-dose anticoagulants (LMWH, VKA, and DOAC) and evaluating recurrent venous thromboembolism (VTE), major bleeding, and/or all-cause mortality were included. Reviewers identified studies, extracted data, and assessed the quality of the evidence in duplicate. A frequentist network meta-analysis, which uses direct and indirect evidence to simultaneously compare multiple interventions, was performed using a random-effects approach. Results are reported as pooled relative risks (RRs) with 95% confidence intervals (CIs). We included 13 RCTs (n = 6292): 7 compared LMWHs with VKAs, 4 compared DOACs with VKAs, and 2 compared DOACs with LMWHs. The risk of recurrent VTE was significantly reduced by 28% and 54% with a DOAC compared to an LMWH and a VKA, respectively. Low-molecular-weight heparins significantly reduced the risk of recurrent VTE by 36% versus VKAs. The risk of major bleeding was 14% higher with DOACs compared to LMWHs and 15% and 25% lower with DOACs and LMWHs versus VKAs, although 95% CIs included unity for each. The risk of all-cause mortality appeared similar for all 3 comparisons (RR = 1.0 for each comparison). Direct-acting oral anticoagulants appeared superior in reducing recurrent VTE in patients with CAT compared to LMWH and VKAs, but an increased risk of major bleeding versus LMWH cannot be ruled out.
-
4.
Low molecular weight heparin for the prevention of deep venous thrombosis after total knee arthroplasty: A systematic review and meta-analysis.
Xia, ZN, Zhou, Q, Zhu, W, Weng, XS
International journal of surgery (London, England). 2018;(Pt A):265-275
-
-
Free full text
-
Abstract
BACKGROUND To systematically evaluate the prophylaxis efficacy of low-molecular-weight heparin (LMWH) in the prevention of deep venous thrombosis (DVT) after total knee arthroplasty (TKA). METHOD PubMed, Cochrane, Embase, Wanfang, CNKI, and VIP databases were searched by index words to identify the eligible RCTs; relevant literature sources were also searched. The latest research was conducted in March 2017. Relative risks (RR), mean difference (MD), and their corresponding 95% confidence intervals (95% CIs) were used to analyze the main outcomes. RESULT A total of 22 articles were included in the meta-analysis with a total number of 11,320 patients (5543 in the LMWH group and 5777 in the control group). The results indicated that in the LMWH group, the incidence of DVT (OR: 0.57, 95% CI: 0.41-0.77) and wound complications (SMD: 0.96, 95% CI: 0.75-1.22) was significantly lower than that in the control group. Furthermore, LMWH also increased the occurrence of bleeding event (OR: 1.57, 95% CI: 1.31-1.88) and the total blood transfused (SMD: 0.12, 95% CI: 0.04-0.19). However, no statistical difference was found in blood loss (SMD: -0.26, 95% CI: -0.65-0.14) between the two group. In the subgroup analysis, the incidence of DVT was significantly decreased in the ardeparin sodium group (OR: 0.70, 95%CI: 0.53-0.94) and the dalteparin group (OR:0.40, 95%CI:0.32-0.50). CONCLUSION Our meta-analysis demonstrated that LMWH is obviously efficacious in the prophylaxis of DVT after TKA. However, it has some negative effects, such as the increase in the number of bleeding events and the total blood transfused.
-
5.
Tinzaparin for Long-Term Treatment of Venous Thromboembolism in Patients With Cancer: A Systematic Review and Meta-Analysis.
Martínez-Zapata, MJ, Mathioudakis, AG, Mousa, SA, Bauersachs, R
Clinical and applied thrombosis/hemostasis : official journal of the International Academy of Clinical and Applied Thrombosis/Hemostasis. 2018;(2):226-234
Abstract
Patients with cancer are at increased risk of recurrent venous thromboembolism (VTE) and bleeding. Thus, long-term treatment with anticoagulants for secondary prevention is challenging. The objective of this review was to evaluate current evidence on the safety and efficacy of tinzaparin compared with other anticoagulants for long-term VTE treatment in patients with cancer. Based on a preregistered protocol, we identified randomized controlled trials (RCTs) comparing long-term tinzaparin (therapeutic dose: 175 IU/kg) versus other anticoagulants for at least 3 months after an acute episode of VTE that included adult patients with underlying malignancy. We extracted predefined, clinically relevant outcomes of patients with cancer and, using standard methodology, pooled available data and assessed risk of bias and quality of evidence for each study. Three open-label RCTs evaluating 1169 patients with cancer were included in the analysis. Tinzaparin was associated with a significantly lower risk of recurrent VTE at the end of treatment (relative risk [RR], [95% confidence interval] 0.67 [0.46-0.99]) and at longest follow-up (RR: 0.58 [0.39-0.88]) and showed a lower risk of clinically relevant non-major bleeding at the end of treatment (RR: 0.71 [0.51-1.00]). No significant between-treatment differences were found for all-cause mortality (RR: 1.09 [0.91-1.30]) or fatal and non-fatal major bleeding events (RR: 1.06 [0.56-1.99]). The overall quality of evidence was deemed moderate, mainly due to small sample size in 2 of the studies and limited number of events in the meta-analyses. In conclusion, both short- and long-term treatments with tinzaparin were found to be superior to vitamin K antagonists for avoiding recurrences of VTE.
-
6.
Direct oral anti-coagulants compared with vitamin-K inhibitors and low-molecular-weight-heparin for the prevention of venous thromboembolism in patients with cancer: A meta-analysis study.
Brunetti, ND, Gesuete, E, De Gennaro, L, Correale, M, Caldarola, P, Gaglione, A, Di Biase, M
International journal of cardiology. 2017;:214-221
Abstract
BACKGROUND Prior meta-analysis studies showed that direct oral anticoagulants (DOAs) are as effective and safe as warfarin for the prevention of recurrences in patients with venous thrombo-embolism(VTE) and cancer. However, randomized studies also showed that low-molecular-weight-heparin (LMWH) performs better than warfarin in subjects with cancer. We therefore aimed to assess whether, even after pooling data with warfarin and LMWH, the use of DOAs remains safe and effective. METHODS We performed a meta-analysis of randomized controlled trials with the aim of assessing the efficacy and safety of DOAs in patients with VTE and cancer. Data on recurrent VTE and major and clinically relevant nonmajor bleeding were analyzed. Data were pooled and compared by ORs and 95% CIs. RESULTS Nine studies were included in the meta-analysis, seven in comparison with VKI, 2 with LMWH, accounting for a total of 1952 patients. VTE recurred in 5.4% and in 5.9% of patients with cancer treated with DOAs and conventional treatment, respectively (OR 0.79; 95% CI, 0.53-1.17; I2 0%). Bleeding occurred in 10.8% and 11% of patients receiving DOAs and conventional treatment, respectively (OR 0.96; 95% CI, 0.71-1.30; I2, 44%). Higher bleeding rates were found when DOAs are compared with LMWH (OR 2.72, 95% CI, 1.05-7.01). CONCLUSIONS DOAs seem to be as effective and safe as conventional treatment for the prevention of VTE in patients with cancer in comparison with VKI. Higher bleeding rates were found when DOAs are compared with LMWH.
-
7.
Efficacy and safety of anticoagulant therapy for the treatment of acute cancer-associated thrombosis: a systematic review and meta-analysis.
Carrier, M, Cameron, C, Delluc, A, Castellucci, L, Khorana, AA, Lee, AY
Thrombosis research. 2014;(6):1214-9
Abstract
BACKGROUND Current clinical practice guidelines all recommend the use of therapeutic doses of low molecular weight heparins (LMWH) for the initial and long-term treatment of cancer-related thrombosis. The use of vitamin-K antagonists (VKA) is acceptable if LMWH is not available. Direct oral anticoagulants (DOACs) have been shown to be comparable to conventional therapy for the acute treatment of VTE but their efficacy and safety in cancer patients remains uncertain. METHODS A systematic literature search strategy was conducted using MEDLINE, EMBASE, and the EBM reviews. Randomized controlled trials (RCTs) reporting rates of recurrent VTE and major bleeding in cancer patients were included. Relative risks (RR) (95% confidence intervals (CI)) for these outcomes were generated. RESULTS A total of 9 RCTs (2310 patients) were included in our analysis. In comparison to VKA, LMWH showed a significant reduction in recurrent VTE events (RR: 0.52; 95% CI: 0.36 to 0.74) whereas DOACs did not (RR: 0.66; 95% CI: 0.39 to 1.11). LMWH was associated with a non significant increase in the risk of major bleeding (RR: 1.06; 95% CI: 0.5 to 2.23) whereas DOACs showed a non significant reduction (RR: 0.78; 95% CI: 0.42 to 1.44). Annualized risks of recurrent VTE and major bleeding among patients randomized to VKA were higher in the LMWH studies as compared to the studies assessing DOACs suggesting that a higher risk cancer population were enrolled in the LMWH studies. CONCLUSIONS LMWH should be used for the treatment of acute cancer-associated thrombosis. The use DOACs cannot be supported until trials comparing them to LMWH are conducted.
-
8.
Long-term treatment of venous thromboembolism with tinzaparin compared to vitamin K antagonists: a meta-analysis of 5 randomized trials in non-cancer and cancer patients.
Laporte, S, Bertoletti, L, Romera, A, Mismetti, P, Pérez de Llano, LA, Meyer, G
Thrombosis research. 2012;(6):853-8
Abstract
PURPOSE Due to its specific pharmacokinetic profile, tinzaparin, a low-molecular-weight heparin (LMWH), appears not to be associated with anti-factor Xa accumulation. Our meta-analysis aimed at determining whether long-term curative doses of tinzaparin is a valuable alternative to vitamin K antagonists (VKA) for the treatment of symptomatic venous thromboembolism (VTE), especially in patients with cancer who are at higher risk of recurrence and bleeding. MATERIALS AND METHODS A systematic literature search identified randomized studies on long-term tinzaparin compared to VKA in patients with VTE. Outcome measures were VTE recurrence, major bleeding, deaths and net clinical benefit combining the three endpoints during the treatment period and at one year. Pooled relative risk was estimated using the logarithm of the relative risk (RR) method based on a fixed-effect model in the overall population and cancer population. RESULTS Five randomized controlled studies were eligible. No difference between groups in VTE recurrence was found in the overall population (RR=0.85 [0.55; 1.31]). In cancer patients, a non-significant 38% VTE risk reduction in favor of tinzaparin was observed on treatment (RR=0.62 [0.30; 1.31]). The difference was significant at the end of follow-up at one year (RR=0.40 [0.19; 0.82], p<0.01). The incidence of major bleeding in the tinzaparin group was not significantly different from the VKA group in the overall population and cancer patients. CONCLUSIONS Tinzaparin appears as a valuable option for long-term treatment of patients in whom VKA are contraindicated or difficult to monitor. Tinzaparin may have a more favorable benefit-risk ratio than VKA in patients with cancer and VTE.
-
9.
Direct thrombin inhibitors versus vitamin K antagonists or low molecular weight heparins for prevention of venous thromboembolism following total hip or knee replacement.
Salazar, CA, Malaga, G, Malasquez, G
The Cochrane database of systematic reviews. 2010;(4):CD005981
-
-
Free full text
-
Abstract
BACKGROUND Patients who have undergone total hip or knee replacement (THR, TKR) have a high risk of developing venous thromboembolism (VTE) following surgery, despite appropriate anticoagulation with warfarin or low molecular weight heparin (LMWH). New anticoagulants are under investigation. OBJECTIVES To examine the efficacy and safety of prophylactic anticoagulation with direct thrombin inhibitors (DTIs) versus LMWH or vitamin K antagonists in the prevention of VTE in patients undergoing THR or TKR. SEARCH STRATEGY The Cochrane Peripheral Vascular Disease Group searched their Specialized Register (last searched 12 March 2010) and CENTRAL (last searched 2010, Issue 2). SELECTION CRITERIA Randomised controlled trials. DATA COLLECTION AND ANALYSIS Three reviewers independently assessed methodological quality and extracted data in pre-designed tables. The reported follow-up events were included MAIN RESULTS We included 14 studies included involving 21,642 patients evaluated for efficacy and 27,360 for safety. No difference was observed in major VTE in DTIs compared with LMWH in both types of operations (odds ratio (OR) 0.91; 95% confidence interval (CI) 0.69 to 1.19), with high heterogeneity (I(2) 71%). No difference was observed with warfarin (OR 0.85; 95% CI 0.63 to 1.15) in TKR, with no heterogeneity (I(2) 0%).More total bleeding events were observed in the DTI group (in ximelagatran and dabigatran but not in desirudin) in patients subjected to THR (OR 1.40; 95% CI 1.06, 1.85; I(2) 41%) compared with LMWH. No difference was observed with warfarin in TKR (OR 1.76; 95% CI 0.91 to 3.38; I(2) 0%). All-cause mortality was higher in the DTI group when the reported follow-up events were included (OR 2.06; 95% CI 1.10 to 3.87).Studies that initiated anticoagulation before surgery showed less VTE events; those that began anticoagulation after surgery showed more VTE events in comparison with LMWH. Therefore, the effect of the DTIs compared with LMWH appears to be influenced by the time of initiation of coagulation more than the effect of the drug itself.The results obtained from sensitivity analysis, did not differ from the analysed results; this strengthens the value of the results. AUTHORS' CONCLUSIONS Direct thrombin inhibitors are as effective in the prevention of major venous thromboembolism in THR or TKR as LMWH and vitamin K antagonists. However, they show higher mortality and cause more bleeding than LMWH. No severe hepatic complications were reported in the analysed studies. Use of ximelagatran is not recommended for VTE prevention in patients who have undergone orthopedic surgery. More studies are necessary regarding dabigatran.
-
10.
Low molecular weight heparin for the prophylaxis of thromboembolism in women with prosthetic mechanical heart valves during pregnancy.
Oran, B, Lee-Parritz, A, Ansell, J
Thrombosis and haemostasis. 2004;(4):747-51
Abstract
Increased thromboembolic events occur in women with mechanical prosthetic valves during pregnancy, and selecting an effective and safe anticoagulant is still a challenge. Low molecular weight heparin (LMWH) is a promising alternative, but a recent warning and label change about its use in patients with mechanical prosthetic valves has caused confusion among physicians. The aim of the present study was to review the risks of maternal and fetal complications with mechanical heart valves treated with LMWH during pregnancy. We performed a review of the current medical literature through MEDLINE and EMBASE (1989 to 2004). Additional data sources included abstract proceedings, and reference lists of selected articles. Among 81 pregnancies in 75 women, the proportion of valve thrombosis was 8.64% (7/81; 95% CI, 2.52%-14.76%). The frequency of overall thromboembolic complication (TEC) was 12.35% (10/81; 95% CI, 5.19%-19.51%). Nine of ten patients with TEC received a fixed dose of LMWH and two of these received a fixed low dose of LMWH. Among 51 pregnancies whose anti-factor Xa levels were monitored, only one patient was reported to have a thromboembolic complication. The frequency of live births with LMWH was 87.65% (95%CI, 80.49%-94.81%). In pregnant women with mechanical heart valves, LMWH appears to be a suitable option to a vitamin K antagonist. The use of LMWH warrants monitoring and appropriate dose adjustments to maintain a 4-6 hr post-injection anti-factor Xa level at a minimum of 1.0 U/ml to decrease the incidence of TEC.