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Randomised controlled trials (RCTs) are considered the gold standard of clinical research as they use rigorous methodologies, detailed protocols, pre-specified statistical analyses and well-defined patient cohorts. However, RCTs do not take into account the complexity of real-world clinical decision-making. To tackle this, real-world data are being increasingly used to evaluate the long-term safety and effectiveness of a given therapy in routine clinical practice and in patients who may not be represented in RCTs, addressing key clinical questions that may remain. Real-world evidence plays a substantial role in supporting the use of non-vitamin K antagonist (VKA) oral anticoagulants (NOACs) in clinical practice. By providing data on patient profiles and the use of anticoagulation therapies in routine clinical practice, real-world evidence expands the current awareness of NOACs, helping to ensure that clinicians are well-informed on their use to implement patient-tailored clinical decisions. There are various issues with current anticoagulation strategies, including under- or overtreatment and frequent monitoring with VKAs. Real-world studies have demonstrated that NOAC use is increasing (Dresden NOAC registry and Global Anticoagulant Registry in the FIELD-AF [GARFIELD-AF]), as well as reaffirming the safety and effectiveness of rivaroxaban previously observed in RCTs (XArelto on preveNtion of sTroke and non-central nervoUS system systemic embolism in patients with non-valvular atrial fibrillation [XANTUS] and IMS Disease Analyzer). This article will describe the latest updates in real-world evidence across a variety of methodologies, such as non-interventional studies (NIS), registries and database analyses studies. It is anticipated that these studies will provide valuable clinical insights into the management of thromboembolism, and enhance the current knowledge on anticoagulant use and outcomes for patients.

Today, direct oral anticoagulants (DOAC) are widely used alternatives to Vitamin-K antagonists (VKA). Women of reproductive age may become pregnant during anticoagulation and, while VKA carry an embryotoxic potential, the risk of DOAC embryopathy is unknown. As a result, some patients elect to terminate pregnancy for fear of DOAC embryotoxicity. To assess the risk of DOAC embryopathy, we reviewed cases of DOAC exposure in pregnancy collected from physicians, literature and pharmacovigilance systems of drug authorities and manufacturers. A total of 357 reports including duplicates were available from which 233 unique cases could be identified. Information on pregnancy outcome was available in only 137/233 cases (58.8 %): 67 live births (48.9 %); 31 miscarriages (22.6 %); 39 elective pregnancy terminations (28.5 %). In 93 cases (39.9 %) no outcome data were available (including 3 cases of ongoing pregnancy). Of the 137 pregnancies with reported outcomes, seven showed abnormalities (5.1 %) of which three (2.2 %) could potentially be interpreted as embryopathy: live birth with facial dysmorphism; miscarriage in week 10 with limb abnormality; elective pregnancy termination due to a foetal cardiac defect in a woman who had to terminate a previous pregnancy due to Fallot tetralogy. Within its limitations (small numbers, incomplete outcome data) our results do not indicate that DOAC exposure in pregnancy carries a high risk of embryopathy or that DOAC exposure per se should be used to direct patient counselling towards pregnancy termination. Pregnancy outcome data are inconsistently captured in pharmacovigilance databases indicating the strong need for a more robust system of reporting.

The effectiveness and safety of rivaroxaban for stroke prevention in atrial fibrillation (SPAF) demonstrated in ROCKET AF needs to be confirmed in daily care. To evaluate effectiveness and safety of rivaroxaban therapy in SPAF patients in daily care, we used data from an ongoing, prospective, non-interventional registry of more than 2700 patients on novel oral anticoagulants in daily care. Between October 1, 2011 and February 28, 2013, a total of 1204 SPAF patients receiving rivaroxaban were enrolled. During a mean follow-up of 796.2 ± 207.3 days, the combined endpoint of stroke/transient ischaemic attack/systemic embolism occurred at a rate of 2.03/100 patient-years in the intention-to-treat analysis (95 % confidence interval [CI] 1.5-2.7) and at 1.7/100 patient-years in the on-treatment analysis (events within 3 days after last intake). On-treatment rates were higher in patients selected for 15 mg rivaroxaban (n=384) once daily [OD] compared with the 820 patients selected for 20 mg OD (2.7 [95 % CI 1.6-4.2] vs 1.25/100 patient-years [95 % CI 0.8-1.9]). On treatment, major bleeding occurred at a rate of 3.0/100 patient-years and significantly more often in patients receiving the 15 mg OD dose compared with the 20 mg OD dose (4.5 vs 2.4/100 patient-years). Rivaroxaban treatment discontinuation occurred in a total of 277 patients during follow-up (12.0/100 patient-years in Kaplan-Meier analysis). Our data contribute to the confirmation of effectiveness and relative safety of rivaroxaban in daily-care patients. Furthermore, rivaroxaban discontinuation rates were considerably lower than those reported for vitamin K antagonists.

Atrial fibrillation (AF) patients treated with well-controlled vitamin K antagonists (VKAs) may benefit less from non-vitamin K antagonist oral anticoagulants (NOACs) because they are supposed to be at low risk of thromboembolic and bleeding complications. However, little is known about the selection, management, and outcome of such "stable" VKA patients in current practice. We assessed characteristics, VKA persistence and 12 months' outcome of AF patients selected for VKA continuation. On March 1, 2013, the Dresden NOAC registry opened recruitment of patients continuing on VKA for sites that had been actively recruiting AF patients treated with NOACs in the prior 18 months. Patient characteristics were compared with those of NOAC patients from the same sites. Four hundred twenty-seven VKA patients had a significantly lower bleeding risk profile compared with 706 patients selected for NOAC treatment. For VKA, international normalised ratio time-in-therapeutic range before enrolment was 71 % and increased to 75 % during a mean follow-up of 15 months. Rates of stroke/transient ischaemic attack/systemic embolism were 1.3/100 patient-years (intention-to-treat) and 0.94/100 patient-years (as-treated). On-treatment rate of ISTH major bleeding was 4.15/100 patient-years (95 % CI 2.60-6.29) with a case-fatality rate of 16.3 % (all-cause mortality at day 90 after major bleeding). In conclusion, in daily care, AF patients selected for VKA therapy are healthier than those treated with NOAC, demonstrate a high quality of anticoagulant control and very low stroke rates. However, despite adequate patient selection and INR control, the risk of major VKA bleeding is unacceptably high and bleeding outcome is poor.

The effectiveness and safety of dabigatran for stroke prevention in atrial fibrillation (SPAF) demonstrated in RE-LY needs to be confirmed in daily care. To evaluate treatment persistence, effectiveness and safety of dabigatran therapy in SPAF patients in daily care, we used data from an ongoing, prospective, non-interventional registry of more than 2,500 patients on novel oral anticoagulants in daily care. Between October 1, 2011 and February 28, 2013, a total of 341 SPAF patients receiving dabigatran were enrolled. The combined endpoint of stroke/transient ischaemic attack/systemic embolism occurred at a rate of 2.93/100 patient-years in the intention-to-treat analysis (95%-CI 1.6-4.9) and at 1.9/100 patient-years in the on treatment analysis (events within three days after last intake). On-treatment rates were higher in patients selected for 110 mg dabigatran (n=183) BID compared to the 158 patients selected for 150 mg BID (2.88 [95% CI 1.16- 5.93] vs 0.86/100 patient-years [95% CI 0.10, 3.12]). On treatment, major bleeding occurred at a rate of 2.3/100 patient-years and numerically more often in patients receiving the 110 mg BID dose compared to the 150 mg BID dose (2.9 vs 1.7/100 patient-years). Dabigatran treatment discontinuation occurred in a total of 124 patients during follow-up (25.8 per 100 patient-years in Kaplan Meier analysis). Main reasons for treatment discontinuation were non-bleeding side effects. Our data contribute to the confirmation of effectiveness and relative safety of dabigatran in unselected patients in daily care. However, discontinuation rates are not lower than those reported for patients treated with vitamin K antagonists.

The prevention and treatment of venous thromboembolism (VTE) remains a clinical challenge, primarily owing to drawbacks associated with the use of heparins and vitamin K antagonists (VKAs). These and other factors, including a growing elderly population, mean that VTE presents a continuing burden to patients and physicians. Anticoagulant therapy is a fundamental approach for VTE management. Non-VKA oral anticoagulants, including the factor Xa inhibitors apixaban, edoxaban and rivaroxaban, and the thrombin inhibitor dabigatran, have been studied in phase III trials across a spectrum of thromboembolic disorders. These agents offer simplified care, with similar or improved efficacy and safety outcomes compared with heparins and vitamin K antagonists. There are several factors a physician must consider when prescribing an anticoagulant. An important consideration with all anticoagulant use is bleeding risk, especially in high-risk groups such as the elderly or those with renal impairment or cancer. In orthopaedic patients, other risks include a need for surgical revision or blood transfusion, or wound complications. Therefore, the clinical benefits of an anticoagulant should ideally be balanced with any risks associated with the therapy. Quantitative benefit-risk assessments are lacking, and owing to differences in trial design the non-VKA oral anticoagulants cannot be compared directly. Based on trial and "real-life" data, this review will summarise the clinical data for the non-VKA oral anticoagulants in the prevention and treatment of VTE, focusing on the balance between the benefits and risks of anticoagulation with these drugs, and their potential impact on VTE management.

Background: The direct factor Xa inhibitor rivaroxaban is approved for venous thromboembolism (VTE) treatment in adults. However, in all phase-III trials children or adolescents have not been included. For under-aged VTE patients, current standard treatment consists of low molecular weight heparin or Vitamin K antagonists. Rivaroxaban could be an attractive alternative, however, no data on the pharmacokinetics (PK) of rivaroxaban in adolescents are currently available. PATIENT, METHODS: We report PK data for rivaroxaban derived from a girl (age:15 years), who presented three month after acute deep vein thrombosis, already receiving rivaroxaban therapy. In the steady state of rivaroxaban therapy (20 mg once daily), plasma levels at baseline, 3 and 6 hours after intake of rivaroxaban were measured to evaluate the pharmacokinetics and changes of global coagulation tests., Results: At baseline, a very low trough level of only 9.9 ng/ml rivaroxaban was found. At 3 hours, a peak concentration of 137.76 ng/ml rivaroxaban was observed with a rapid decrease within 6 hours after drug intake, when plasma levels of 34.45 ng/ml were measured. The patients INR and aPTT values reacted correspondingly., Conclusion: Our data indicate that adolescents may exhibit lower peak and trough levels after rivaroxaban intake compared to adult patients, but seem to have similar PK curves during the elimination phase. While our case is the first published case of a successful VTE treatment in an under-aged patient, we strongly discourage the routine use of rivaroxaban in non-adult patients, until data from phase II and III trials are available.