Thirty-day mortality in atrial fibrillation patients with gastrointestinal bleeding in the emergency department: differences between direct oral anticoagulant and warfarin users.

More clinical data are required on the safety of direct oral anticoagulants (DOACs). Although patients treated with warfarin and DOACs have a similar risk of bleeding, short-term mortality after a gastrointestinal bleeding (GIB) episode in DOAC-treated patients has not been clarified. The objective of this study was to assess differences in 30-day mortality in patients treated with DOACs or warfarin admitted to the emergency department (ED) for GIB. This was a multicentre retrospective study conducted over 2 years. The study included patients evaluated at three different EDs for GIB. The baseline characteristics were included. Subsequently, we assessed the differences in past medical history and clinical data between the two study groups (DOAC and warfarin users). Differences between the two groups were evaluated using Kaplan-Meier curves. Among the 284 patients presenting GIB enrolled in the study period, 39.4% (112/284) were treated with DOACs and 60.6% (172/284) were treated with warfarin. Overall, 8.1% (23/284) of patients died within 30 days. Among the 172 warfarin-treated patients, 8.7% (15/172) died within 30 days from ED evaluation. In the 112 DOAC-treated patients, the mortality rate was 7.1% (8/112). The Cox regression analysis, adjusted for possible clinical confounders, and the Kaplan-Meier curves did not outline differences between the two treatment groups. The present study shows no differences between DOACs and warfarin in short-term mortality after GIB.

Healthy User Bias in Comparative Safety Studies for Brand-Name vs. Generic Products: The Example of Warfarin.

Warfarin was selected as a case study to examine confounding when comparing a product across different manufacturers because it is a narrow therapeutic index drug with prevalent beliefs for brand-name superiority. Medicare beneficiaries aged ≥65 years with atrial fibrillation and an incident outpatient warfarin prescription from July 2006 through July 2015 were included in the study population (N = 746,098). Substantial imbalances were observed between brand-name warfarin and generics for (i) clinical comorbidity, (ii) socioeconomic status, (iii) prescriber specialty, (iv) recent ambulatory and emergent care, (v) drug adherence, (vi) pharmacy setting (e.g., retail, mail-order), and (vii) risk scores for bleeding and thrombosis. Patients receiving brand-name warfarin were healthier than patients receiving generic manufactured warfarin. Utilization of generic warfarin products also differed by geographic region and pharmacy setting. Manufacturer-level comparative-safety studies for causal inference should carefully consider the presence of these imbalances and their potential for introducing healthy user bias.

A Review on the New and Old Anticoagulants.

Anticoagulants serve as the primary strategy for the prevention and treatment of both arterial and venous thromboembolism. Anticoagulants disrupt coagulation by interfering at various points in the coagulation cascade. This class of medications does not lyse clots that already exist; rather, it prevents thrombus formation and prevents or slows the extension of an existing clot. For decades, the standard therapy for patients requiring oral anticoagulation was warfarin. However, due to some of the shortcomings of warfarin, including the need for continuous routine monitoring, longtime onset and offset of anticoagulation effect, major food and drug interactions, and high incidence of bleeding, newer agents, termed direct oral anticoagulants, or DOACs were developed. This article will provide a review of clinically important information regarding the most commonly used anticoagulants and their reversal agents.

Assessment of Outcomes of Treatment With Oral Anticoagulants in Patients With Atrial Fibrillation and Multiple Chronic Conditions: A Comparative Effectiveness Analysis.

Importance: Comparative effectiveness and safety of oral anticoagulants in patients with atrial fibrillation (AF) and multiple chronic conditions (MCC) are unknown. Objective: To determine whether there are differences in efficacy and safety of dabigatran, rivaroxaban, and warfarin regarding stroke prevention and bleeding rates, respectively, in elderly patients with AF with MCC. Design, Setting, and Participants: This retrospective comparative effectiveness analysis included data from the population-based Medicare beneficiaries database, evaluating patients with new AF diagnosed from January 1, 2010, to December 31, 2013, who initiated an oral anticoagulant within 90 days of diagnosis. Patients with CHA2DS2-VASc scores of 1 to 3, 4 to 5, and 6 or higher; HAS-BLED scores of 0 to 1, 2, and 3 or higher; and Gagne comorbidity scores of 0 to 2, 3 to 4, and 5 or higher were categorized as having low, moderate, or high morbidity, respectively. Within morbidity categories, patients receiving dabigatran, rivaroxaban, or warfarin were matched using a 3-way propensity matching, and the relative hazards of stroke, major hemorrhage (MH), and death were evaluated. Data analysis included follow-up from the date of initial anticoagulant use through December 31, 2013. Exposures: Rivaroxaban (20 mg once daily), dabigatran (150 mg twice daily), or warfarin therapy. Main Outcomes and Measures: Ischemic stroke, MH, and death. Results: The study cohort included 21 979 patients using dabigatran (mean [SD] age, 75.8 [6.4] years; 51.1% female), 23 177 using rivaroxaban (mean [SD] age, 75.8 [6.4] years; 49.9% female), and 101 715 using warfarin (mean [SD] age, 78.5 [7.2] years; 57.3% female). In the propensity-matched cohorts, there were no differences in stroke rates between the 3 oral anticoagulant groups. Dabigatran users had lower hazard of MH compared with warfarin users among patients with low MCC (hazard ratio [HR], 0.62; 95% CI, 0.47-0.83; P < .001; for MCC defined as low CHA2DS2-VASc score), and similar risk in patients with moderate to high MCC. While there was no difference in MH between rivaroxaban and warfarin users, rivaroxaban users had significantly higher MH risk compared with dabigatran users in the medium and high comorbidity groups (HR, 1.24; 95% CI, 1.04-1.48; P = .02 and HR, 1.28; 95% CI, 1.05-1.56; P = .01, respectively). Dabigatran and rivaroxaban users had lower rates of death compared with warfarin users (HR ranged from 0.52-0.84), across comorbidity levels. Conclusions and Relevance: Oral anticoagulants are similarly effective in stroke prevention among patients with AF with MCC. However, dabigatran and rivaroxaban use may be associated with lower rates of mortality in patients with MCC.

European guidelines on perioperative venous thromboembolism prophylaxis: Patients with preexisting coagulation disorders and after severe perioperative bleeding.

: In patients with inherited bleeding disorders undergoing surgery, we recommend assessment of individual risk for venous thromboembolism, taking into account the nature of the surgery and anaesthetic, type and severity of bleeding disorder, age, BMI, history of thrombosis, the presence of malignancy and other high-risk comorbidities. Venous thromboembolism risk should be balanced against the increased bleeding risk associated with anticoagulant use in patients with known bleeding disorders (Grade 1C). In these patients undergoing major surgery, we recommend against routine postoperative use of pharmacological thromboprophylaxis, especially for patients with haemophilia A and B (Grade 1B). Glomerular filtration rate should be assessed before initiation of each direct oral anticoagulant, and also at least once a year or more frequently as needed, such as postoperatively before the resumption of therapeutic direct oral anticoagulant administration, when it is suspected that renal function could decline or deteriorate (Grade 1C). Reduced dosages of low molecular weight heparins may be used relatively safely during transient severe (<50 × 10 l) thrombocytopaenia (Grade 2C). Monitoring of anti-Xa levels may be used to adjust the doses of low molecular weight heparin in patients with moderate or severe thrombocytopaenia (Grade 2C). The delay between major gastrointestinal bleeding and resuming warfarin should be at least 7 days (Grade 2C). For patients at a high risk of thromboembolism and with a high bleeding risk after surgery, we consider that administering a reduced dose of direct oral anticoagulant on the evening after surgery and on the following day (first postoperative day) after surgery is a good practice (Grade 2B).

Impact on Outcomes of Changing Treatment Guideline Recommendations for Stroke Prevention in Atrial Fibrillation: A Nationwide Cohort Study.

OBJECTIVE: To investigate the impact on outcomes of changing treatment guideline recommendations by comparing the proportion of patients with atrial fibrillation (AF) recommended oral anticoagulants (OACs) under the 2011 and 2014 American College of Cardiology/American Heart Association (ACC/AHA) guidelines. PATIENTS AND METHODS: We used the "National Health Insurance Research Database" in Taiwan, which included 354,649 patients with AF from January 1, 1996 through December 31, 2011. Patients with a CHADS2 (congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, and prior stroke or transient ischemic attack) score of 2 or more and a CHA2DS2-VASc (congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, prior stroke or transient ischemic attack, vascular disease, age 65-74 years, female sex category) score of 2 or more were considered to have a definitive indication for receiving OACs according to the 2011 and 2014 ACC/AHA guidelines, respectively. RESULTS: The percentages of patients with AF recommended OACs increased from 69.3% (n=245,598) under the 2011 guideline to 86.7% (n=307,640) under the new 2014 guidelines, an increment of 17.5% (95% CI, 17.4-17.6). Most women with AF (94.1%) and patients older than 65 years (97.2%) would receive OACs on the basis of the 2014 guidelines. Among patients previously not being recommended OACs in older guidelines, OAC use under the new guidelines was associated with a lower risk of adverse outcomes (ischemic stroke or intracranial hemorrhage or bleeding requiring blood transfusion or mortality) with an adjusted hazard ratio of 0.89 (95% CI, 0.85-0.94). CONCLUSION: In this nationwide cohort study, use of the 2014 guidelines led more patients with AF to receive OACs for stroke prevention, and this increased OAC use was associated with better outcomes. Better efforts to implement guidelines would lead to improved outcomes for patients with AF.

Influence of process parameters on content uniformity of a low dose active pharmaceutical ingredient in a tablet formulation according to GMP.

The article describes the development and production of tablets using direct compression of powder mixtures. The aim was to describe the impact of filler particle size and the time of lubricant addition during mixing on content uniformity according to the Good Manufacturing Practice (GMP) process validation requirements. Processes are regulated by complex directives, forcing the producers to validate, using sophisticated methods, the content uniformity of intermediates as well as final products. Cutting down of production time and material, shortening of analyses, and fast and reliable statistic evaluation of results can reduce the final price without affecting product quality. The manufacturing process of directly compressed tablets containing the low dose active pharmaceutical ingredient (API) warfarin, with content uniformity passing validation criteria, is used as a model example. Statistic methods have proved that the manufacturing process is reproducible. Methods suitable for elucidation of various properties of the final blend, e.g., measurement of electrostatic charge by Faraday pail and evaluation of mutual influences of researched variables by partial least square (PLS) regression, were used. Using these methods, it was proved that the filler with higher particle size increased the content uniformity of both blends and the ensuing tablets. Addition of the lubricant, magnesium stearate, during the blending process improved the content uniformity of blends containing the filler with larger particles. This seems to be caused by reduced sampling error due to the suppression of electrostatic charge.

Consideration of international generic distribution policies on patient outcomes in the United States and Germany.

Generic substitution of narrow therapeutic index drugs can have unintended consequences. Generic switching is often driven by cost incentives, regulations and supply, but may raise concerns about equal bioavailability, therapeutic equivalence and about possible confusion for the patient. Integrated systems of care with active management of patient behaviors, including adherence, may minimize the impact of switching. This article is intended to present policy drivers and potential consequences of generic switching and the role of pharmacist education in minimizing patient risk using warfarin and the pharmaceutical distribution systems of the United States and Germany as examples.

Raman spectroscopy as a complementary tool to assess the content uniformity of dosage units in break-scored warfarin tablets.

Due to the side effects of overdosing, the therapeutic dose of warfarin preparations must be very strictly controlled. In order to make it easier for the patient to take the required dose, two different strategies can be followed: The medicine can be commercialized in different dosages and/or tablets can be scored in order to make them easy to split. The splitting of the tablets introduces the question of how to control that the fractions contain the desirable amount of warfarin. The regulations regarding the content uniformity of dosage unit for scored tablets have changed considerably in the last 10 years, and they are still evolving. Warfarin is commercialized under the trademark of Aldocumar in four different preparations, containing 1, 3, 5 and 10 mg sodium warfarin per tablet. All these tablets are also scored, thus suggesting the possibility of splitting. A quantitative Raman method has been developed for the determination of warfarin in tablets and in the potential fragments, taking into account the score lines on the tablet surface. This method is suggested as an auxiliary procedure to verify the uniformity of API distribution in dividable tablets. A combination of a second derivative and standard normal variate (SNV) was used as spectral pre-treatments, and partial least squares (PLS) as the regression algorithm. The relative standard deviation in API content among portions was found to be less than 5%. An HPLC procedure has been used as a reference analytical method.

Warfarin: what are the clinical implications of an out-of-range-therapeutic international normalized ratio?

Warfarin is a commonly used oral anticoagulant, and has well-established clinical efficacy. However, it has a narrow therapeutic window, and a mode-of-action affected by inter-individual differences and environmental factors. The effectiveness and safety of warfarin are closely related to maintenance of the international normalized ratio (INR) within therapeutic range. A supra-therapeutic INR puts patients at risk of bleeding, whereas a sub-therapeutic INR may not protect against thromboembolic complications. Research suggests a lack of anticoagulation control during warfarin therapy in different settings. Careful monitoring of the INR is essential, especially in geriatric or cancer populations who are at an increased risk of major hemorrhage. Warfarin is an effective treatment but optimization of the risk-benefit ratio is crucial in order to maximize efficacy and safety. Here, we will assess the extent to which INRs are an issue in the management of warfarin therapy, and the effect INRs may have on clinical outcomes.

An audit of INR control in the Australian indigenous setting.

BACKGROUND: Warfarin management can be difficult; many factors can impact on INR control with some factors being unique to the Australian indigenous setting. METHODS: An audit at an urban Aboriginal community controlled health service calculated the time all patients on warfarin were in the target INR therapeutic range. Those patients with the best and the worst values for time in therapeutic range (TTR) were then compared. RESULTS: The 26 identified patients on warfarin were in the target INR therapeutic range 44.9% of the time. Patients with better INR control were older than those with the worst control. There appeared to be no difference between the two groups when comparing other factors. DISCUSSION: INR control was below the cited benchmark for TTR of 60%. However, this may be better than expected in this clinical setting. The small number of patients included in the audit means that any discussion of the causes of better and poorer control must be treated with caution.

Guidelines for the management of patients on oral anticoagulants requiring dental surgery.

The objective of these guidelines is to provide healthcare professionals, including primary care dental practitioners, with clear guidance on the management of patients on oral anticoagulants requiring dental surgery. The guidance may not be appropriate in all cases and individual patient circumstances may dictate an alternative approach.

Are brand-name and generic warfarin interchangeable? Multiple n-of-1 randomized, crossover trials.

BACKGROUND: Warfarin is a commonly used anticoagulant in North America. Several generic formulations have been approved, raising concern over the safety and efficacy of these products compared with brand-name Coumadin. OBJECTIVE: To ensure that generic warfarin products can be safely interchanged with Coumadin. METHODS: Multiple n-of-1 randomized, double-blind, crossover trials switched outpatients (N = 7) between a generic warfarin formulation (Apo-warfarin) and Coumadin over 30 weeks. Study patients took each drug for five 3-week periods, with international normalized ratio (INR) measurements taken twice per period. Inter- and intrapatient differences between generic warfarin and Coumadin were compared, and overall study patient results were compared with those of a Coumadin control group. RESULTS: There were no differences between warfarin products in terms of mean INR results or number of dosage adjustments required. There also was no difference in INR variation based on warfarin formulation (p > 0.69), nor was a patient and warfarin interaction found (p > 0.81). The INR results were not influenced by whether patients were maintained on Coumadin only (control group) or interchanged between Coumadin and generic warfarin (p = 0.98). CONCLUSIONS: It appears that patients can safely and effectively switch between generic warfarin and Coumadin.

Oral vitamin K produces a normal INR within 24 hours of its administration in most patients discontinuing warfarin.

A randomized, blinded study in 30 patients was undertaken. This study found that low dose oral vitamin K was more effective than placebo when used to correct the INR in patients who are discontinuing warfarin. Larger studies will be required to determine if the use of oral vitamin K, for example in patients who are temporarily discontinuing warfarin to undergo interventional procedures, is safe and effective.