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Oral anticoagulation in people with cancer who have no therapeutic or prophylactic indication for anticoagulation.
Kahale, LA, Hakoum, MB, Tsolakian, IG, Matar, CF, Barba, M, Yosuico, VED, Terrenato, I, Sperati, F, Schünemann, H, Akl, EA
The Cochrane database of systematic reviews. 2017;(12):CD006466
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Abstract
BACKGROUND Oral anticoagulants may improve the survival of people with cancer through both an antitumor effect and antithrombotic effect, yet increase the risk of bleeding. OBJECTIVES To evaluate the efficacy and safety of oral anticoagulants in ambulatory people with cancer undergoing chemotherapy, hormonal therapy, immunotherapy or radiotherapy, but otherwise have no standard therapeutic or prophylactic indication for anticoagulation. SEARCH METHODS We conducted a comprehensive literature search in February 2016 that included a major electronic search of Cochrane Central Register of Controlled Trials (CENTRAL) (2016, Issue 1), MEDLINE (Ovid) and Embase (Ovid); handsearching of conference proceedings; checking of references of included studies; a search for ongoing studies; and using the 'related citation' feature in PubMed. As part of the living systematic review approach, we are running continual searches and will incorporate new evidence rapidly after it is identified. This update of the systematic review is based on the findings of a literature search conducted on 14 December 2017. SELECTION CRITERIA Randomized controlled trials (RCTs) assessing the benefits and harms of vitamin K antagonist (VKA) or direct oral anticoagulants (DOAC) in ambulatory people with cancer. These participants are typically undergoing systemic anticancer therapy, possibly including chemotherapy, target therapy, immunotherapy or radiotherapy, but otherwise have no standard therapeutic or prophylactic indication for anticoagulation. DATA COLLECTION AND ANALYSIS Using a standardized form, we extracted data in duplicate on study design, participants, intervention outcomes of interest and risk of bias. Outcomes of interest included all-cause mortality, symptomatic venous thromboembolism (VTE), symptomatic deep vein thrombosis (DVT), pulmonary embolism (PE), major bleeding, minor bleeding and health-related quality of life (HRQoL). We assessed the certainty of evidence for each outcome using the GRADE approach (GRADE Handbook). MAIN RESULTS Of 8545 identified citations, including 7668 unique citations, 16 papers reporting on 7 RCTs fulfilled the inclusion criteria. These trials enrolled 1486 participants. The oral anticoagulant was warfarin in six of these RCTs and apixaban in the seventh RCT. The comparator was either placebo or no intervention. The meta-analysis of the studies comparing VKA to no VKA did not rule out a clinically significant increase or decrease in mortality at one year (risk ratio (RR) 0.95, 95% confidence interval (CI) 0.87 to 1.03; risk difference (RD) 29 fewer per 1000, 95% CI 75 fewer to 17 more; moderate certainty evidence). One study assessed the effect of VKA on thrombotic outcomes. The study did not rule out a clinically significant increase or decrease in PE when comparing VKA to no VKA (RR 1.05, 95% CI 0.07 to 16.58; RD 0 fewer per 1000, 95% CI 6 fewer to 98 more; very low certainty evidence), but found that VKA compared to no VKA likely decreases the incidence of DVT (RR 0.08, 95% CI 0.00 to 1.42; RD 35 fewer per 1000, 95% CI 38 fewer to 16 more; low certainty evidence). VKA increased both major bleeding (RR 2.93, 95% CI 1.86 to 4.62; RD 107 more per 1000, 95% CI 48 more to 201 more; moderate certainty evidence) and minor bleeding (RR 3.14, 95% CI 1.85 to 5.32; RD 167 more per 1000, 95% CI 66 more to 337 more; moderate certainty evidence).The study assessing the effect of DOAC compared to no DOAC did not rule out a clinically significant increase or decrease in mortality at three months (RR 0.24, 95% CI 0.02 to 2.56; RD 51 fewer per 1000, 95% CI 65 fewer to 104 more; low certainty evidence), PE (RR 0.16, 95% CI 0.01 to 3.91; RD 28 fewer per 1000, 95% CI 33 fewer to 97 more; low certainty evidence), symptomatic DVT (RR 0.07, 95% CI 0.00 to 1.32; RD 93 fewer per 1000, 95% CI 100 fewer to 32 more; low certainty evidence), major bleeding (RR 0.16, 95% CI 0.01 to 3.91; RD 28 fewer per 1000, 95% CI 33 fewer to 97 more; low certainty evidence); and minor bleeding (RR 4.43, 95% CI 0.25 to 79.68; RD 0 fewer per 1000, 95% CI 0 fewer to 8 more; low certainty evidence). AUTHORS' CONCLUSIONS The existing evidence does not show a mortality benefit from oral anticoagulation in people with cancer but suggests an increased risk for bleeding.Editorial note: this is a living systematic review. Living systematic reviews offer a new approach to review updating in which the review is continually updated, incorporating relevant new evidence, as it becomes available. Please refer to the Cochrane Database of Systematic Reviews for the current status of this review.
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Balancing thromboembolic and bleeding risk with non-vitamin K antagonist oral anticoagulants (NOACs): A systematic review and meta-analysis on gender differences.
Proietti, M, Cheli, P, Basili, S, Mazurek, M, Lip, GY
Pharmacological research. 2017;:274-282
Abstract
Sex and gender differences have been reported in atrial fibrillation (AF), especially in relation to differences in thromboembolic and bleeding risks. More recently, pharmacological treatments have changed following the introduction of non-vitamin K antagonist oral anticoagulants (NOACs) progressively replacing vitamin K antagonists (VKAs). The aims of this systematic review are to summarize the available evidence on NOACs and the relationship to major adverse outcomes according to sex. Moreover, we performed a meta-analysis of data from the phase III clinical trials investigating the sex effect on stroke/systemic embolic events (SEE) and major bleeding. Our literature review found small differences in NOACs efficacy and safety between male and female patients, even if so far available literature is limited to post-hoc ancillary analyses from randomized trials and one cohort study. Meta-analysis from NOAC trials found a differential effect of NOACs, with male patients being more protected from stroke/SEE and female patients more protected from major bleeding events. Further data are needed to fully elucidate sex differences in AF patients treated with NOACs.
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Anticoagulation Regimens During Pregnancy in Patients With Mechanical Heart Valves: A Systematic Review and Meta-analysis.
Xu, Z, Fan, J, Luo, X, Zhang, WB, Ma, J, Lin, YB, Ma, SH, Chen, X, Wang, ZP, Ou, JS, et al
The Canadian journal of cardiology. 2016;(10):1248.e1-1248.e9
Abstract
BACKGROUND Managing anticoagulation in pregnant women with mechanical heart valves remains challenging. Our aim was to evaluate the effectiveness and safety of 4 regimens in these women. METHODS Relevant studies published before June 2015 were collected in several databases and analyzed with RevMan version 5.3 and SPSS version 19.0. Four regimens were defined as follows: a regimen of a vitamin K antagonist (VKA) throughout pregnancy; a heparin (H)/VKA regimen using VKAs except for unfractionated heparin (UFH) or low molecular weight heparin (LMWH) during 6-12 weeks of pregnancy; a LMWH regimen of adjusted LMWH doses throughout pregnancy; and a UFH regimen of adjusted UFH doses throughout pregnancy. The low warfarin dose in the VKA regimen was defined as 5 mg/d or less. RESULTS Fifty-one studies comprising 2113 pregnancies in 1538 women were included. The rate of fetal wastage was significantly higher in the high warfarin dose subgroup than in the low dose one. Compared with the H/VKA regimen, the rate of maternal major thromboembolic event in the low-dose VKA regimen group was significantly lower, although the fetal outcomes were similar. Compared with the H/VKA regimen, the rate of fetal wastage in the LMWH regimen group was significantly lower, and the maternal outcomes were similar. The UFH regimen presented the worst maternal and fetal outcomes. CONCLUSIONS In the absence of large prospective trials, this meta-analysis showed that the VKA regimen should be best for pregnant women with a low warfarin dose, and the H/VKA regimen might be reasonable for those with a high warfarin dose. The LMWH regimen could be used for those who refuse VKA.
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Extended Anticoagulant and Aspirin Treatment for the Secondary Prevention of Thromboembolic Disease: A Systematic Review and Meta-Analysis.
Marik, PE, Cavallazzi, R
PloS one. 2015;(11):e0143252
Abstract
BACKGROUND Patients who have had an unprovoked deep venous thrombosis (DVT) or pulmonary embolus (PE) are at a high risk for recurrent venous thromboembolism (VTE). Extended "life-long" anticoagulation has been recommended in these patients. However, the risk benefit ratio of this approach is controversial and the role of the direct oral anticoagulants (DOACs) and aspirin is unclear. Furthermore, in some patients with a "weak provoking factor" there is clinical equipoise regarding continuation or cessation of anticoagulant therapy after treatment of the acute VTE event. OBJECTIVE A systematic review and meta-analysis to determine the risks (major bleeding) and benefits (recurrent VTE and mortality) of extended anticoagulation with vitamin k antagonists (VKA), DOACs and aspirin in patients with an unprovoked VTE and in those patients with clinical equipoise regarding continuation or cessation of anticoagulant therapy. In addition, we sought to determine the risk of recurrent VTE events once extended anti-thrombotic therapy was discontinued. DATA SOURCES MEDLINE, Cochrane Register of Controlled Trials, citation review of relevant primary and review articles. STUDY SELECTION Randomized placebo-controlled trials (RCTs) that compared the risk of recurrent VTE in patients with an unprovoked DVT or PE who had been treated for at least 3 months with a VKA or a DOAC and were then randomized to receive an oral anti-thrombotic agent or placebo for at least 6 additional months. We included studies that included patients in whom clinical equipoise existed regarding the continuation or cessation of anticoagulant therapy. DATA EXTRACTION Independent extraction of articles by both authors using predefined data fields, including study quality indicators. Data were abstracted on study size, study setting, initial event (DVT or PE), percentage of patients where the initial VTE event was unprovoked, the number of recurrent VTE events, major bleeds and mortality during the period of extended anticoagulation in the active treatment and placebo arms. In addition, we recorded the event rate once extended treatment was stopped. Meta-analytic techniques were used to summarize the data. Studies were grouped according to the type of anti-thrombotic agent. DATA SYNTHESIS Seven studies which enrolled 6778 patients met our inclusion criteria; two studies evaluated the extended use of Coumadin, three studies evaluated a DOAC and two studies evaluated the use of aspirin. The duration of followup varied from 6 to 37 months. In the Coumadin and aspirin studies 100% of the randomized patients had an unprovoked VTE, while in the DOAC studies between 73.5% and 93.2% of the VTE events were unprovoked. In the control group recurrent VTE occurred in 9.7% of patients compared to 2.8% in the active treatment group (OR 0.21; 95% CI 0.11-0.42, p<0.0001). VKA, DOACs and aspirin significantly reduced the risk of recurrent VTE, with VKA and DOACs being significantly more effective than aspirin. Major bleeding events occurred in 12 patients in the control group (0.4%) and 25 of 3815 (0.6%) patients in the active treatment group (OR 1.64; 95% CI 0.69-3.90, NS). There were 39 (1.3%) deaths in control patients and 33 (0.9%) deaths in the anti-thrombotic group during the treatment period (OR 0.73; 95% CI 0.40-1.33, NS). Patients whose initial VTE event was a PE were more likely to have a recurrent PE than a DVT. The annualized event rate after discontinuation of extended antithrombotic therapy was 4.4% in the control group and 6.5% in the active treatment arm. CONCLUSIONS VKA, DOACs and aspirin significantly reduced the risk of recurrent VTE, with DOACs and VKA being more effective than aspirin. The decision regarding life-long anticoagulation following an unprovoked DVT or PE should depend on the patients' risk for recurrent PE as well as the patients' values and preferences.
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Meta-analysis of randomized controlled trials reveals an improved clinical outcome of using genotype plus clinical algorithm for warfarin dosing.
Liao, Z, Feng, S, Ling, P, Zhang, G
Journal of thrombosis and thrombolysis. 2015;(2):228-34
Abstract
Previous studies have raised interest in using the genotyping of CYP2C9 and VKORC1 to guide warfarin dosing. However, there is lack of solid evidence to prove that genotype plus clinical algorithm provides improved clinical outcomes than the single clinical algorithm. The results of recent reported clinical trials are paradoxical and needs to be systematically evaluated. In this study, we aim to assess whether genotype plus clinical algorithm of warfarin is superior to the single clinical algorithm through a meta-analysis of randomized controlled trials (RCTs). All relevant studies from PubMed and reference lists from Jan 1, 1995 to Jan 13, 2014 were extracted and screened. Eligible studies included randomized trials that compared clinical plus pharmacogenetic algorithms group to single clinical algorithm group using adult (≥ 18 years) patients with disease conditions that require warfarin use. We further used fix-effect models to calculate the mean difference or the risk ratios (RRs) and 95% CIs to analyze the extracted data. The statistical heterogeneity was calculated using I(2). The percentage of time within the therapeutic INR range was considered to be the primary clinical outcome. The initial search strategy identified 50 citations and 7 trials were eligible. These seven trials included 1,910 participants, including 960 patients who received genotype plus clinical algorithm of warfarin dosing and 950 patients who received clinical algorithm only. We discovered that the percentage of time within the therapeutic INR range of the genotype-guided group was improved compared with the standard group in the RCTs when the initial standard dose was fixed (95% CI 0.09-0.40; I(2) = 47.8%). However, for the studies using non-fixed initial doses, the genotype-guided group failed to exhibit statistically significant outcome compared to the standard group. No significant difference was observed in the incidences of adverse events (RR 0.94, 95% CI 0.84-1.04; I(2) = 0%, p = 0.647) and death rates (RR 1.36, 95% CI 0.46-4.05; I(2) = 10.4%, p = 0.328) between the two groups. Allocation to genotype plus clinical algorithm may be associated with a significant improvement of the percentage of time within the therapeutic INR range for patients adopting fixed dose of warfarin. The incidence of total adverse events and death rates did not differ between these two groups. Further experiments need to be conducted to confirm these findings.
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Meta-analysis of risk of stroke and thrombo-embolism with rivaroxaban versus vitamin K antagonists in ablation and cardioversion of atrial fibrillation.
Nairooz, R, Sardar, P, Pino, M, Aronow, WS, Sewani, A, Mukherjee, D, Paydak, H, Maskoun, W
International journal of cardiology. 2015;:345-53
Abstract
BACKGROUND Anticoagulation in cardioversion and ablation of atrial fibrillation is imperative for reducing thrombo-embolic events. Ample information is available about the use of warfarin and vitamin K antagonists (VKA) but few trials examine safety and efficacy of rivaroxaban in these procedures. We aim to explore the hypothesis that rivaroxaban causes equal thrombo-embolic and bleeding events when used in atrial fibrillation patients undergoing ablation or cardioversion compared to VKA. METHODS We searched the online databases as well as conference abstracts till December 2014 for studies comparing rivaroxaban with VKA in atrial fibrillation patients undergoing catheter ablation or cardioversion. We report events as Odds ratio using random effects model except when event rates were less than 1% we used Peto Odds Ratio. RESULTS A total of 8872 atrial fibrillation patients in 15 studies undergoing either catheter ablation or cardioversion were included in this analysis. There were significantly lower stroke events with rivaroxaban compared with VKA (Peto Odds Ratio (POR) 0.33, 95% confidence interval (CI) [0.11, 0.95]; P=0.04), and significantly less thrombo-embolic events with rivaroxaban compared with VKA (POR 0.46, 95% CI [0.21, 0.97]; P=0.04). Major and minor bleeding were equal with rivaroxaban versus VKA (Odds Ratio (OR) 0.92, 95% CI [0.62, 1.36]; P=0.68) and (OR 0.81,95% CI [0.58, 1.11]; P=0.19) respectively. CONCLUSION The use of rivaroxaban in ablation and cardioversion of atrial fibrillation may be associated with decreased risk of stroke and thromboembolism with equal bleeding risk compared to VKA.
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Oral anticoagulation in patients with cancer who have no therapeutic or prophylactic indication for anticoagulation.
Akl, EA, Kahale, L, Terrenato, I, Neumann, I, Yosuico, VE, Barba, M, Sperati, F, Schünemann, H
The Cochrane database of systematic reviews. 2014;(7):CD006466
Abstract
BACKGROUND Several basic research and clinical studies have led to the hypothesis that oral anticoagulants may improve the survival of patients with cancer through an antitumor effect in addition to their antithrombotic effect. OBJECTIVES To evaluate the efficacy and safety of oral anticoagulants in patients with cancer with no therapeutic or prophylactic indication for anticoagulation. SEARCH METHODS We performed a comprehensive search for studies of anticoagulation in patients with cancer including 1. a February 2013 electronic search of the following databases: Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, and EMBASE; 2. a handsearch of the American Society of Clinical Oncology (starting with its first volume, 1982) and of the American Society of Hematology (starting with the 2003 issue); 3. checking of references of included studies; 4. use of the 'related citation' feature in PubMed; and 5. searching clinical trials.gov for ongoing studies. SELECTION CRITERIA Randomized controlled trials (RCTs) comparing vitamin K antagonist or other oral anticoagulants with no intervention or placebo in patients with cancer without clinical evidence of venous thromboembolism. DATA COLLECTION AND ANALYSIS Using a standardized data form, we extracted data on risk of bias, participants, interventions and outcomes of interest that included all-cause mortality, venous thromboembolism, major bleeding, and minor bleeding. MAIN RESULTS Of 9559 identified citations, seven RCTs (eight reports) fulfilled the inclusion criteria. The oral anticoagulant was warfarin in six of these RCTs and apixaban in the seventh RCT. The comparator was either placebo or no intervention. The use of warfarin had no effect on mortality at six months (risk ratio (RR) 0.98; 95% confidence interval (CI) 0.82 to 1.22), one year (RR 0.97; 95% CI 0.89 to 1.04), two years (RR 0.98; 95% CI 0.81 to 1.18), or five years (RR 0.92; 95% CI 0.83 to 1.01). One study assessed the effect of warfarin on venous thromboembolism and did not show or exclude a beneficial or detrimental of effect (RR 0.15; 95% CI 0.02 to 1.20). Warfarin increased both major bleeding (RR 4.24; 95% CI 1.86 to 9.65) and minor bleeding (RR 3.19; 95% CI 1.83 to 5.55). We judged the quality of evidence as moderate for all outcomes.The study assessing the effect of apixaban did not show or exclude a beneficial effect or detrimental of apixaban on mortality at six months (RR 0.16; 95% CI 0.01 to 1.66); major bleeding (RR 0.62; 95% CI 0.06 to 6.63); and minor bleeding (RR 2.87; 95% CI 0.16 to 51.82). We judged the quality of evidence as low for all outcomes. AUTHORS' CONCLUSIONS Existing evidence does not suggest a mortality benefit from oral anticoagulation in patients with cancer while the risk for bleeding is increased.
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Duration of treatment with vitamin K antagonists in symptomatic venous thromboembolism.
Middeldorp, S, Prins, MH, Hutten, BA
The Cochrane database of systematic reviews. 2014;(8):CD001367
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Abstract
BACKGROUND Currently, the most frequently used secondary treatment for patients with venous thromboembolism (VTE) consists of vitamin K antagonists (VKA) targeted at an international normalized ratio (INR) of 2.5 (range 2.0 to 3.0). However, based on the continuing risk of bleeding and uncertainty regarding the risk of recurrent VTE, discussion on the proper duration of treatment with VKA for these patients is ongoing. Several studies have compared the risks and benefits of different durations of VKA in patients with VTE. This is the third update of a review first published in 2000. OBJECTIVES To evaluate the efficacy and safety of different durations of treatment with vitamin K antagonists in patients with symptomatic venous thromboembolism. SEARCH METHODS For this update, the Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched October 2013) and the Cochrane Central Register of Controlled Trials (CENTRAL) 2013, Issue 9. SELECTION CRITERIA Randomized controlled clinical trials comparing different durations of treatment with vitamin K antagonists in patients with symptomatic venous thromboembolism. DATA COLLECTION AND ANALYSIS Three review authors (SM, MP, and BH) extracted the data and assessed the quality of the trials independently. MAIN RESULTS Eleven studies with a total of 3716 participants were included. A consistent and strong reduction in the risk of recurrent venous thromboembolic events was observed during prolonged treatment with VKA (risk ratio (RR) 0.20, 95% confidence interval (CI) 0.11 to 0.38) independent of the period elapsed since the index thrombotic event. A statistically significant "rebound" phenomenon (ie, an excess of recurrences shortly after cessation of prolonged treatment) was not found (RR 1.28, 95% CI 0.97 to 1.70). In addition, a substantial increase in bleeding complications was observed for patients receiving prolonged treatment during the entire period after randomization (RR 2.60, 95% CI 1.51 to 4.49). No reduction in mortality was noted during the entire study period (RR 0.89, 95% CI 0.66 to 1.21, P = 0.46). AUTHORS' CONCLUSIONS In conclusion, this review shows that treatment with VKA strongly reduces the risk of recurrent VTE for as long as they are used. However, the absolute risk of recurrent VTE declines over time, although the risk for major bleeding remains. Thus, the efficacy of VKA administration decreases over time since the index event.
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Novel oral anticoagulants in patients with renal insufficiency: a meta-analysis of randomized trials.
Sardar, P, Chatterjee, S, Herzog, E, Nairooz, R, Mukherjee, D, Halperin, JL
The Canadian journal of cardiology. 2014;(8):888-97
Abstract
BACKGROUND Recent reports suggest altered antithrombotic efficacy and higher risk of bleeding with new oral anticoagulants (NOACs) in patients with renal insufficiency. A meta-analysis was performed to evaluate the efficacy and safety with recommended doses of NOAC compared with conventional treatment in patients with renal insufficiency. METHODS PubMed, Cochrane Library, EMBASE, EBSCO, Web of Science, and CINAHL databases were searched from January 1, 2001 through March 23, 2014. Randomized controlled trials that compared NOACs (rivaroxaban, apixaban, and dabigatran) with comparators (vitamin K antagonist/warfarin, low molecular weight heparin, aspirin, placebo) were selected. We defined moderate renal insufficiency as creatinine clearance (estimated glomerular filtration rate [eGFR]) of 30-49 mL/min, and mild renal insufficiency as eGFR 50-79 mL/min. RESULTS There were 40,693 patients with renal insufficiency in 10 trials. Compared with other anticoagulants in patients with mild renal insufficiency there was significantly less major or clinically relevant nonmajor bleeding (odds ratio [OR], 0.81; 95% confidence interval [CI], 0.72-0.90) and stroke or systemic embolism (OR, 0.70; 95% CI, 0.54-0.92) with NOACs. Using random effects meta-analysis, there was significantly less stroke or systemic embolism (OR, 0.72; 95% CI, 0.57-0.92) and a trend toward less major or clinically relevant nonmajor bleeding (OR, 0.82; 95% CI, 0.59-1.14) with the NOACs among patients with moderate renal insufficiency, and this became statistically significant when evaluated using a fixed effects model. NOACs showed efficiency comparable with conventional anticoagulants for prevention of venous thromboembolism or related mortality. CONCLUSIONS In patients with renal insufficiency, recommended doses of novel anticoagulants are noninferior and relatively safe compared with conventional anticoagulants.
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The prevalence of oral anticoagulation in patients with atrial fibrillation in Portugal: Systematic review and meta-analysis of observational studies.
Caldeira, D, Barra, M, David, C, Costa, J, Ferreira, JJ, Pinto, FJ
Revista portuguesa de cardiologia : orgao oficial da Sociedade Portuguesa de Cardiologia = Portuguese journal of cardiology : an official journal of the Portuguese Society of Cardiology. 2014;(9):555-60
Abstract
INTRODUCTION AND OBJECTIVES Oral anticoagulation (OAC) is an effective treatment in the prevention of thromboembolic events in patients with atrial fibrillation (AF). The aim of this review was to estimate the prevalence of OAC therapy in patients with AF in Portugal. METHODS MEDLINE, the Index of Portuguese Medical Journals and SIBUL (the Bibliographic Catalog of the Integrated Library System of the University of Lisbon) were searched for Portuguese observational studies reporting the proportion of anticoagulated patients with AF. The pooled estimated prevalence of anticoagulated patients and respective 95% confidence interval (CI) were determined by means of a meta-analysis. RESULTS Seven studies were included for analysis, of which four were conducted in a hospital environment and three in the general community. These studies enrolled a total of 891 patients with AF. The pooled estimated prevalence of anticoagulated patients was 40% (95% CI: 32-48%). CONCLUSIONS The prevalence of OAC in Portuguese AF patients is low. There is a need to promote change in OAC prescribing habits for AF patients in Portugal, in accordance with international guidelines.