Healthcare resources and costs associated with nonvalvular atrial fibrillation in Spain: apixaban versus acenocoumarol.

Aim: Healthcare resources usage and costs associated to nonvalvular atrial fibrillation (NVAF) were analyzed in Spain. Methods: This is an observational and retrospective study on patients with NVAF who started their treatment with apixaban or acenocoumarol between 1 January 2015 and 31 December 2017. Results: 2160 patients treated with apixaban were paired (1:1) with patients treated with acenocoumarol (propensity score matching). Apixaban reduced the incidence of strokes and systemic embolisms, minor and major bleedings and deaths, versus acenocoumarol. Apixaban led to reductions of 80, 55 and 43% in costs related to nursing visits, hospitalizations, and emergency visits, respectively, leading to annual cost savings of €274/patient, from the perspective of society. Conclusion: Our results suggested that apixaban is a cost-effective alternative for patients with NVAF.

Cost-effectiveness of direct oral anticoagulants versus vitamin K antagonist in atrial fibrillation: A study protocol using Real-World Data from Catalonia (FantasTIC Study).

BACKGROUND: Anticoagulant therapy is used for stroke prevention and proved to be effective and safe in the long term. The study aims to analyse the cost-effectiveness relationship of using of direct-acting oral anticoagulants vs vitamin K antagonists to prevent ischaemic stroke in patients with nonvalvular atrial fibrillation, including all the active ingredients marketed in Spain, prescribed for 2 years in the Primary Care service of the Institut Català de la Salut. METHODS: Population-based cohort study, in which the cost of the 2 treatment groups will be evaluated. Direct costs (pharmacy, primary care, emergency and hospitalization) and indirect costs (lost productivity) will be included from a social perspective. Effectiveness (assessed as the occurrence of a health event, the 1 of primary interest being stroke) will be determined, with a 2-year time horizon and a 3% discount rate. The average cost of the 2 groups of drugs will be compared using a regression model to determine the factors with the greatest influence on determining costs. We will carry out a univariate ('one-way') deterministic sensitivity analysis. DISCUSSION: We hope to provide relevant information about direct and indirect costs of oral anticoagulants, which, together with aspects of effectiveness and safety, could help shape the consensual decision-making of evaluating bodies.

Perioperative bridging of vitamin K antagonist treatment in patients with atrial fibrillation: only a very small group of patients benefits.

AIMS: Bridging anticoagulation in atrial fibrillation (AF) patients who need to interrupt vitamin K antagonists for procedures is a clinical dilemma. Currently, guidelines recommend clinicians to take the stroke and bleeding risk into consideration, but no clear thresholds are advised. To aid clinical decision making, we aimed to develop a model in which periprocedural bridging therapy is compared with withholding anticoagulation in AF patients, for several bleeding and stroke risk groups. METHODS AND RESULTS: A model was developed to simulate both a bridge and a non-bridge cohort, using simulated international normalized ratio (INR) values for patients on warfarin, acenocoumarol, and phenprocoumon. For both clinical strategies, stroke and bleeding risks were included and outcomes were stratified by CHA2DS2-VASc or CHADS2 and HAS-BLED groups. Quality-adjusted life expectancy was the main outcome considered. Our analyses show bridging to only be beneficial for patients with HAS-BLED scores equal or lower to 2 and with CHA2DS2-VASc scores of 6 or higher. For patients using acenocoumarol bridging may be beneficial starting at a CHA2DS2-VASc score of 7. Post-procedural time to therapeutic INR has a significant influence on the results: no significant benefit of bridging was found for patients reaching therapeutic INR values within 5 days. CONCLUSION: When deciding whether to bridge anticoagulation, clinicians should consider the patient's individual stroke and bleeding risk, while also considering the patient's post-procedural INR management. In practice, only a small subset of patients is expected to benefit from bridging anticoagulation treatment.

The international normalized ratio (INR): What reagent, what instrument? The assessment of the agreement between INR values according to different reagent/instrument combinations.

WHAT IS KNOWN AND OBJECTIVE: The international normalized ratio (INR) is widely used to monitor patients on vitamin K antagonists. This study aimed to assess the agreement of INR values obtained with different thromboplastin/instrument combinations. MATERIAL AND METHODS: International normalized ratio was determined on plasmas from 330 patients undergoing antivitamin K treatment (with acenocoumarol), using two calibration methods and four reagent/instrument combinations: Both Neoplastine CI and Neoplastine CI Plus on STA-R instrument from Diagnostica STAGO, Asnières, France; and both Thromborel S and Innovin on SYSMEX 2100i instrument from Siemens Health Care Diagnostics, Marbung, Germany. The agreement analysis was done using the Bland-Altman plot and the Cohen Kappa coefficient. RESULTS: The mean of the differences between the INR values and the limits of agreement were -0.07 [-0.51 to 0.38] for the Neoplastine CI plus and Neoplastine CI reagents, -0.08 [-1.18 to 1.03] for the Thromborel S and Innovin reagents when the INR was calculated, -0.1 [-1.15 to 0.95] for the Thromborel S and Innovin reagents when the INR was directly calibrated and -0.1 [-0.7 to 0.5] for the Neoplastine CI plus and Thromborel S. Cohen's kappa coefficients were 0.94, 0.76, 0.85 and 0.82, respectively. NEW FINDINGS AND CONCLUSION: The agreement between the four reagent/instrument combinations was high enough to classify patients as inefficaciously or efficaciously anticoagulated. The data interpretation should always be related to the clinical purpose.

Predictors for total hospital and cardiology cost claims among patients with atrial fibrillation initiating dabigatran or acenocoumarol in The Netherlands.

AIMS: The prevalence of atrial fibrillation (AF) has increased over the past years due to aging of the population, and healthcare costs associated with AF reflect a significant financial burden. The aim of this study was to explore predictors for the real-world AF-related in-hospital costs in patients that recently initiated anticoagulation with acenocoumarol or dabigatran. METHODS: Predictors for claimed total hospital care costs and cardiology costs in AF patients were explored by using hospital financial claims data from propensity score matched patient groups in a large Dutch community hospital. This study analyzed the total dataset (n = 766) and carried out a secondary analysis for all matched pairs of anticoagulation naïve AF patients (n = 590) by ordinal regression. RESULTS: Dabigatran was a predictor for significantly lower cardiology and total hospital care costs (Odds Ratio [OR] = 0.43, 95% confidence interval (CI) = 0.33-0.57; and OR = 0.60, 95% CI = 0.46-0.79, respectively). Female gender was a predictor for lower total hospital care costs. Predictors for an increase in total hospital care costs were the occurrence of stroke or systemic embolism, major bleeding, and minor bleeding. The costs predictors were comparable when limiting the analysis to patients that were anticoagulation naïve. Age and CHA2DS2-VASc were not predictors for either cardiology or total hospital care costs in both analyses. CONCLUSION: Dabigatran treatment was as a predictor for lower cardiology costs and lower total hospital care costs in AF patients that initiated oral anticoagulation.

Latin American Clinical Epidemiology Network Series - Paper 2: Apixaban was cost-effective vs. acenocoumarol in patients with nonvalvular atrial fibrillation with moderate to severe risk of embolism in Chile.

OBJECTIVE: Nonvalvular atrial fibrillation (NVAF) is a risk factor for ischemic stroke and systemic embolism. New oral anticoagulants are currently available. The objective of this study was to assess the incremental cost-utility ratio (ICUR) for apixaban vs. acenocoumarol in patients treated in Chile's public health system. STUDY DESIGN AND SETTING: We assessed cost-utility from the payer perspective with a lifetime Markov model. Epidemiologic characteristics, costs, and utilities were obtained from a Chilean cohort; data were completed with information from international literature. RESULTS: Incremental costs when using apixaban vs. acenocoumarol over a lifetime are CH$2,108,600 with an incremental effectiveness of 0.173 years of life gained (YLG) and 0.182 quality-adjusted life-year (QALY). The ICUR of apixaban vs. acenocoumarol was CH$12,188,439 per YLG and CH$11,585,714 per QALY. One to 3 times gross domestic product (GDP) per capita threshold is acceptable based on World Health Organization (WHO) norms. Chilean GDP per capita was CH$7,797,021 in 2013. The sensitivity analysis shows that these results are sensitive to the ischemic stroke risk with apixaban, and the intracranial hemorrhage risk due to the use of acenocoumarol. CONCLUSION: The use of apixaban in patients with NVAF in moderate-to-high risk of stroke is cost-effective, considering the payment threshold suggested by WHO.

The SAMe-TT2R2 Score Predicts Poor Anticoagulation Control in AF Patients: A Prospective 'Real-world' Inception Cohort Study.

OBJECTIVES: International guidelines recommend that an average individual time in therapeutic range should be >65% to 70% for optimal efficacy and safety outcomes while taking a vitamin K antagonist. The Sex, Age (<60 years); Medical history (at least 2 of the following: hypertension, diabetes, coronary artery disease/myocardial infarction, peripheral arterial disease, congestive heart failure, previous stroke, pulmonary disease, hepatic or renal disease); Treatment (interacting drugs, eg, amiodarone for rhythm control) [all 1 point]; and the current Tobacco use (2 points) and Race (non-Caucasian; 2 points) (SAMe-TT2R2) score would help decision making by identifying those patients with newly diagnosed atrial fibrillation who could do well on vitamin K antagonists. The study objective was to validate the predictive value of the SAMe-TT2R2 score for discriminating those who would achieve a high time in the therapeutic range (≥65%) in a prospective "real-world" cohort of patients with atrial fibrillation initiating oral anticoagulation therapy with vitamin K antagonists. METHODS: We studied an inception cohort of consecutive patients with nonvalvular atrial fibrillation who initiated oral anticoagulation in our outpatient anticoagulation clinic. The baseline SAMe-TT2R2 score was calculated. At 6 months, we calculated the time in therapeutic range using a linear method. RESULTS: We included 459 patients, of whom 222 (47%) were male. Their median age was 76 years (interquartile range, 70-82 years), median Cardiac failure or dysfunction, Hypertension, Age over 75 years [Doubled], Diabetes, Stroke [Doubled] - Vascular disease, Age between 65-74 and Sex category [Female] (CHA2DS2-VASc) score was 4 (3-5), and median Hypertension, Abnormal Renal/Liver Function, Stroke, Bleeding History or Predisposition, Labile INR, Elderly, Drugs/Alcohol Concomitantly (HAS-BLED) score was 3 (2-3). The median SAME-TT2R2 score was 2 (1-2). At 6 months, the mean ± standard deviation time in therapeutic range was 64% ± 17% overall, and 248 patients (54%) had a time in therapeutic range value >65%. Patients with a SAME-TT2R2 score 0 to 1 had a mean time in therapeutic range of 67% ± 18%, whereas patients with a SAME-TT2R2 score ≥2 had a mean time in therapeutic range of 61% ± 16% (P < .001). The odds ratio for having a low time in therapeutic range value was 2.10 (95% confidence interval, 1.44-3.06; P < .001) for those patients with a SAME-TT2R2 score ≥2. CONCLUSIONS: In a prospective "real-world" inception cohort of patients with atrial fibrillation initiating oral anticoagulation with acenocoumarol, we have validated the clinical value of the SAME-TT2R2 score for the identification of patients who would have poor-quality anticoagulation. Thus, rather than imposing a "trial of vitamin K antagonists" for such patients (and exposing such patients to thromboembolic risks), we can a priori identify those patients who can (not cannot) do well on a vitamin K antagonists. Such patients would benefit from additional strategies for improving anticoagulation control with vitamin K antagonists or alternative oral anticoagulant drugs.

Genotype-guided dosing of coumarin derivatives: the European pharmacogenetics of anticoagulant therapy (EU-PACT) trial design.

The narrow therapeutic range and wide interpatient variability in dose requirement make anticoagulation response to coumarin derivatives unpredictable. As a result, patients require frequent monitoring to avert adverse effects and maintain therapeutic efficacy. Polymorphisms in VKORC1 and CYP2C9 jointly account for about 40% of the interindividual variability in dose requirements. To date, several pharmacogenetic-guided dosing algorithms for coumarin derivatives, predominately for warfarin, have been developed. However, the potential benefit of these dosing algorithms in terms of their safety and clinical utility has not been adequately investigated in randomized settings. The European Pharmacogenetics of Anticoagulant Therapy (EU-PACT) trial will assess, in a single-blinded and randomized controlled trial with a follow-up period of 3 months, the safety and clinical utility of genotype-guided dosing in daily practice for the three main coumarin derivatives used in Europe. The primary outcome measure is the percentage time in the therapeutic range for international normalized ratio. This report describes the design and protocol for the trial.

A study on the safety, efficacy, and efficiency of sulodexide compared with acenocoumarol in secondary prophylaxis in patients with deep venous thrombosis.

This study was carried out to study the safety and efficacy of a fixed dosage of sulodexide compared to adjusted dosages (INR) of acenocoumarol as secondary prophylaxis in patients with deep vein thrombosis (DVT) in lower limbs. An economic evaluation based on the criteria of use in normal clinical practice was also performed. One hundred and fifty patients of both sexes were included, all over 18 years of age and diagnosed with proximal DVT of the lower limbs by color echo-Doppler, and with clinical evolution of less than 1 month. The patients were initially treated with low-molecular-weight heparin (LMWH) and urokinase in accordance with the established protocol. They were then randomized to continue treatment with acenocoumarol and INR adjustments every 30 days, or with sulodexide. Treatment was extended for 3 months with monthly follow-up visits and a final visit at 3 months posttreatment. No differences between the groups were detected concerning demographic or basal characteristics in clinical evolution or adverse reactions. In the group treated with sulodexide, no major/minor hemorrhagic complications were detected. On the other hand, in the acenocoumarol group, 1 major hemorrhage and 9 minor hemorrhages were produced (13.3%), reaching statistical difference in relation to the sulodexide group (p = 0.014; CI from 95% of 4.7% to 19.4%). Regarding the economic impact, treatment costs with sulodexide are much less than those with acenocoumarol, the data confirmed by the sensitivity analyses performed. The results prove the efficacy, safety, and efficiency of sulodexide as a secondary prophylaxis in thromboembolic disease, avoiding hemorrhagic risks and the monitoring of patients, and providing significant savings to the health system.

Abrupt versus gradual withdrawal of vitamin K antagonist treatment in patients with venous thromboembolic disease: assessment of hypercoagulability and clinical outcome.

BACKGROUND: It is yet unclear whether vitamin K antagonist treatment should be stopped abruptly or gradually after an episode of venous thromboembolism. The mode of withdrawal might influence a potential development of a hypercoagulable state, which could influence the risk for recurrent disease. METHODS: We prospectively studied 37 consecutive patients in whom acenocoumarol was discontinued either abrupt (18) or gradually (19) (2/3 and 1/3 of the initial dose for one week). Blood sampling was performed at various time points up to 18 days after complete withdrawal and was analysed for INR, prothrombin fragment F1 + 2 and D-dimer. All patients were clinically followed-up for the assessment of the association between hypercoagulability and occurrence of disease such as recurrent venous thromboembolism or malignancy. RESULTS: An approximately fourfold increase was observed (median increase from 0.3 to 1.3 nmol/l) in the F1 + 2 levels after both abrupt and gradual withdrawal and in the D-dimer concentrations in the abrupt withdrawal group (0.10 to 0.44 mg/l), while those in whom acenocoumarol was discontinued gradually showed a less pronounced increase of the D-dimer levels (0.11 to 0.29 mg/L) (not significant). During follow-up one recurrent venous thromboembolic event occurred in each group, and a diagnosis of cancer was made four times. All these patients had the highest D-dimer concentrations measured in the entire study group. CONCLUSIONS: This study indicates the potential for a hypercoagulable state after acenocoumarol discontinuation, which was not prevented by tapering the acenocoumarol dose. D-dimer, measured 2 to 3 weeks after acenocoumarol withdrawal, might be an important tool to identify patients at risk for recurrent venous thromboembolism and/or for the presence of an underlying malignancy.

Assessment of therapeutic quality control in a long-term anticoagulant trial in post-myocardial infarction patients.

Various methods have been described to evaluate efficacy of anticoagulant therapy using the international normalized ratio (INR). We compared the following approaches: (1) total INR's or the most recent measurement; (2) percent time within therapeutic range, with INR changing directly or halfway between visits; and (3) total observation time assuming INR changing linearly. The study population comprised 1700 post myocardial infarction patients. Treatment comprised 3725 patient-years. There were 61,471 INR assessments with target therapeutic level of 2.8-4.8. Acenocoumarol as well as phenprocoumon were employed. Therapeutic achievement in the first months of treatment was low: less than 60% of INR's were in range. Treatment stabilized after 6 months. Patients on acenocoumarol were within range 70% of the time compared to 80% for phenprocoumon. Method 3 is preferred because it incorporates time and is capable of calculating incidence rates at different INR levels. Our findings call for an urgent improvement of standard of anticoagulant control in the first months following commencement of treatment.

[Checking oral anticoagulation in capillary blood]. / Control de la anticoagulación oral en sangre capilar.

PURPOSE: To check out the reproducibility and costs of prothrombin time (PT) determination as a control of oral anticoagulant therapy (OAT) in plasma and capillary blood. PATIENTS AND METHODS: The study was carried out in two phases: along two years, 1,700 patients with OAT were controlled, 700 of them in the hospital outpatient clinic. In 149 patients INR was simultaneously determined in both capillary and venous blood. The 700 patients receiving acenocoumarin who had been controlled in 1991 according to the conventional plasma-sample fashion, were controlled in the second year (i.e., 1992) by means of capillary blood testing, a comparison of the costs of each method and the need for anticoagulant drugs being undertaken. Venous blood PT was assessed with reagent thromboplastin (Tromborel S) in an Electra-1000 (MLA) system. An automated Trombotrack system was used for the capillary blood tests using Thrombotest as current procedure. The results were expressed as INR in both methods. The statistical evaluation of the results was carried out by means of Student's t, variance analysis, and correlation study. RESULTS: No significant differences were found in the anticoagulation intervals attained from venous or capillary blood samples. No significant differences were seen in 87 patients on whom the test was repeated in two samples drawn from a single capillary puncture. The weekly OAT doses of 30 patients along six months were analysed. The need for anticoagulant drugs was similar (17.4 vs 17.2 mg/patient/week). The mean INR in 1991 was 2.82 and the mean drug-need was 15.24 mg/week, whereas in 1992 the mean INR was 2.86 and the need for anticoagulant was 15.49 mg/week. The costs of the conventional method were 103.6 Pta, this being 70 Pta for capillary blood, which means a 32% savings. CONCLUSIONS: OAT control by means of PT performed on capillary blood must be considered a substitutive method for the venous blood assay due to its efficacy, simplicity and lower costs.

Two-dimensional echocardiographic assessment of anticoagulant therapy in left ventricular thrombosis early after acute myocardial infarction.

This study was designed to assess, by two-dimensional echocardiography, the effects of anticoagulant therapy on left ventricular thrombosis detected after acute myocardial infarction. Thirty-eight patients with left ventricular thrombi detected by two-dimensional echocardiology within 5 weeks (mean 4) of the onset of infarction were randomly assigned to the following groups: group A consisted of 19 patients who received oral anticoagulants (acenocoumarin 1-6 mg daily regulated to keep prothrombin time within the range of 25 to 35%) and group B which consisted of 19 non-treated control patients. Seventeen patients from both groups were restudied 15 days, 3 months and one year later to evaluate the changes in size of thrombi. Echocardiographic examinations were read blindly; a significant decrease in ventricular thrombus size was taken as a greater than or equal to 5 mm reduction of thickness in the apical views. In Group A, 9 patients showed a complete resolution of thrombus at the 15 day study; at one year, thrombus had resolved in 15 and persisted unchanged in size in 2 patients. The mean dimension of thrombi in patients of group A was 18 +/- 6.6 mm at the screening examination and decreased to 6.6 mm, 3.8 mm and 2.2 mm, respectively, at 15 days, 3 months and one year follow-up studies. Among 17 patients of group B at the 15 day study, two had resolution of thrombus and 15 were unchanged; at the one year examination thrombus was resolved in 4, decreased in size in 4 and persisted unchanged in 9 patients. Analysis of variance of the dimensional changes of thrombi in the two groups of patients confirmed a significant efficacy of anticoagulant therapy (P less than 0.001). On the basis of our results we conclude that full-dose anticoagulant therapy, started early (within 5 weeks) after acute myocardial infarction, is effective in the resolution of left ventricular thrombosis.

An assessment of an amidolytic assay for factor VII in the laboratory control of oral anticoagulants.

A comparison has been made between the prothrombin time test using British Comparative Thromboplastin (BCT) and a chromogenic substrate assay for factor VII in the assessment of laboratory control of oral anticoagulants in short-term and long-term patients. Opportunity was also taken to compare the findings with parallel results obtained with the venous Thrombotest technique and a specific clotting assay for factor VII. There was good agreement between the amidolytic factor VII assay, using a method modified from Seligsohn et al (1978) with the Quick test using BCT and Thrombotest in 60 long-term patients. Tests in 53 patients within the first 3 weeks of starting oral anticoagulant administration gave less satisfactory agreement between the above amidolytic method and the conventional tests. In contrast, there was a good correlation between the two conventional tests in both groups and also between the clotting and amidolytic factor VII method. Although the results are an improvement on previous, less satisfactory correlations between the BCT prothrombin time method and amidolytic assays for factor II and X, the present study indicates the limitations of a specific clotting assay versus a broad spectrum extrinsic clotting test in oral anticoagulant control. While not warranting the routine use of the chromogenic assay for factor VII in place of the prothrombin time using BCT, the factor VII amidolytic assay offers a limited but dependable guide to dosage in long-term patients. The complexity of the technique in its present form militates against its adoption for routine anticoagulant control in hospital laboratories.