Comparative effectiveness of direct oral anticoagulants and warfarin in patients with cancer and atrial fibrillation.
ABSTRACT: Randomized clinical trials comparing direct oral anticoagulants (DOACs) to warfarin in cancer patients have not been performed. We evaluated the effectiveness and associated risk of DOACs vs warfarin, as well as comparisons of DOACs, in a large population of cancer patients with nonvalvular atrial fibrillation (AF). Using the MarketScan databases, we identified 16?096 AF patients (mean age, 74 years) initiating oral anticoagulant and being actively treated for cancer between 2010 and 2014. Anticoagulant users were matched by age, sex, enrollment date, and drug initiation date. Study end points were identified with diagnostic codes and included ischemic stroke, severe bleeding, other bleeding, and venous thromboembolism (VTE). Cox regression was used to estimate associations of anticoagulants with study end points. Compared with warfarin, rates of bleeding (hazard ratio [95% confidence interval]) were similar in rivaroxaban (1.09 [0.79, 1.39]) and dabigatran (0.96 [0.72, 1.27]) users, whereas apixaban users experienced lower rates (0.37 [0.17, 0.79]). Rates of ischemic stroke did not differ among anticoagulant users. Compared with warfarin, rate of VTE (hazard ratio [95% confidence interval]) was lower among rivaroxaban (0.51 [0.41, 0.63]), dabigatran (0.28 [0.21, 0.38]), and apixaban (0.14 [0.07, 0.32]) users. In head-to-head comparisons among DOACs, dabigatran users had lower rates of VTE than rivaroxaban users; apixaban users had lower rates of VTE and severe bleeding than rivaroxaban users. In this population of patients with AF and cancer, DOAC users experienced lower or similar rates of bleeding and stroke compared with warfarin users, and a lower rate of incident VTE.
Project description:Background:Direct oral anticoagulants (DOACs), namely rivaroxaban, apixaban, dabigatran, and edoxaban, are now included together with warfarin as standards of care for the primary treatment of venous thromboembolism (VTE). The extent to which the DOACs have been adopted since receiving US Food and Drug Administration (FDA) approval is unknown. Objective:To document temporal trends in oral anticoagulant (OAC) prescriptions among anticoagulant-naïve patients initiating OACs for VTE primary treatment in the United States and to report participant characteristics by OAC prescribed for the year 2017. Methods:MarketScan databases for years 2012 through 2017 were used to identify VTE cases and comorbidities using International Classification of Diseases codes and prescriptions for OACs via outpatient pharmaceutical claims data. Results:The 137 203 VTE cases were on average (± standard deviation) 56.7 ± 16.0 years old and 49.9% female. Warfarin was prescribed to 98.7% of VTE patients receiving an OAC in quarter 1 (January through March) of 2012. By quarter 4 (October through December) of 2017, warfarin was prescribed to 17.5%, while rivaroxaban was prescribed to 42.7%, apixaban to 38.6%, dabigatran to 1.3%, and edoxaban to <0.1%. In 2017, the comorbidity burden was highest among patients prescribed warfarin, intermediate among patients prescribed apixaban, and lowest among patients prescribed rivaroxaban. Conclusions:Rivaroxaban and apixaban use to treat VTE has increased dramatically since receiving FDA approval, whereas warfarin use has plummeted. Dabigatran and edoxaban are infrequently prescribed. Given widespread usage of rivaroxaban and apixaban, there is a need for continued monitoring of the comparative effectiveness of these OAC therapies in real-world settings.
Project description:OBJECTIVE:Oral anticoagulation (OAC) prescribed to AF patients for the prevention of cardioembolic complications likely has the added benefit of preventing venous thromboembolism (VTE). This study evaluated, among AF patients who are anticoagulated, whether type of OAC was associated with subsequent VTE risk. METHODS:Non-valvular AF patients prescribed OACs between 2010 and September 2015 were identified via the MarketScan administrative claims databases. OACs included warfarin and direct OACs (DOACs: dabigatran, rivaroxaban, and apixaban). Incident VTE was defined by ICD-9-CM codes. Patients were matched on age, sex, CHA2DS2-VASc, and high-dimensional propensity scores. The final analysis included 117,912?AF patients. RESULTS:In total, 1357 VTE events accrued over a mean follow-up of 484 days. In multivariable-adjusted, propensity score-matched Cox models, relative to new users of warfarin, risk of incident VTE was lower among new users of dabigatran [hazard ratio (95% confidence interval)?=?0.55 (0.47-0.66)] and apixaban [0.51 (0.39-0.68)], but similar among new users of rivaroxaban [1.01 (0.87-1.19)]. In head-to-head DOAC comparisons, VTE risk was lower among users of dabigatran [0.48 (0.36-0.64)] and apixaban [0.61 (0.47-0.78)] vs rivaroxaban. Findings were mostly similar across patient sub-groups. CONCLUSIONS:In this large practice-based population of AF patients prescribed OACs for primary prevention of stroke and systemic embolization, subsequent risk of VTE was lowest among those prescribed apixaban and dabigatran, while risk was similar with prescriptions for warfarin and rivaroxaban. Among AF patients prescribed OACs, lowering the risk of VTE may be an additional benefit of apixaban and dabigatran, beyond the reduced bleeding risk observed in randomized clinical trials.
Project description:Direct oral anticoagulants (DOACs) are at least as efficacious and safe as warfarin among non-valvular atrial fibrillation (NVAF) patients; limited evidence is available regarding NVAF patients with heart failure (HF). US Medicare enrollees with NVAF and HF initiating DOACs (apixaban, rivaroxaban, dabigatran) or warfarin were selected. Propensity score matching and Cox models were used to estimate the risk of stroke/systemic embolism (SE), major bleeding (MB), and major adverse cardiac events (MACE) comparing DOACs versus warfarin and DOACs versus DOACs. We identified 10,570 apixaban-warfarin, 4,297 dabigatran-warfarin, 15,712 rivaroxaban-warfarin, 4,263 apixaban-dabigatran, 10,477 apixaban-rivaroxaban, and 4,297 dabigatran-rivaroxaban matched pairs. Compared to warfarin, apixaban had lower rates of stroke/SE (hazard ratio = 0.64, 95% confidence interval = 0.48-0.85), MB (hazard ratio = 0.66, 0.58-0.76), and MACE (hazard ratio = 0.73,0.67-0.79); dabigatran and rivaroxaban had lower rates of MACE (hazard ratio = 0.87,0.77-0.99; hazard ratio = 0.84, 0.79-0.89, respectively). Rivaroxaban had a lower stroke/SE rate (hazard ratio = 0.65, 0.52-0.81) and higher MB rate (hazard ratio = 1.18, 1.08-1.30) versus warfarin. Compared to dabigatran and rivaroxaban, apixaban had lower MB (hazard ratio = 0.71, 0.57-0.89; hazard ratio = 0.55, 0.49-0.63) and MACE rates (hazard ratio = 0.80, 0.69-0.93; hazard ratio = 0.86, 0.79-0.94), respectively. All DOACs had lower MACE rates versus warfarin; differences were observed in stroke/SE and MB. Our findings provide insights about OAC therapy among NVAF patients with HF.
Project description:Oral anticoagulants used for the primary treatment of venous thromboembolism (VTE) include warfarin and the more recently introduced direct oral anticoagulants (DOACs), including rivaroxaban, apixaban, dabigatran and edoxaban. Information on the comparative safety of these medications in routine clinical practice is lacking. We identified patients with diagnoses for VTE and prescriptions for oral anticoagulants using claims data from a large U.S. insurance database from 2012 to 2017. Marginal structural logistic models were used to examine associations between type of oral anticoagulant and risk of all-cause mortality. Of 62,431 enrolees in this analysis, 51% were female and the mean age was 61.9 years. Initial oral anticoagulant prescriptions were for warfarin (n?=?35,704), rivaroxaban (n?=?21,064) and apixaban (n?=?5,663). A total of 1,791 deaths occurred within 6 months of the initial oral anticoagulant prescription. Risk of all-cause mortality was not associated with having a prescription for warfarin versus any DOAC or between any head-to-head DOAC comparisons. Also, associations generally did not vary when stratified by VTE type, sex, age, co-morbidities (including renal disease) or anti-platelet medication use. In this observational study, the associations with all-cause mortality comparing DOACs versus warfarin agree with results from previous clinical trials and observational studies, while the associations for head-to-head DOAC comparisons provide new information on the comparative safety of DOACs. Our findings suggest that other criteria such as patient preference, cost, recurrent VTE risk or bleeding risk should be used when determining the choice of anticoagulant for the primary treatment of VTE.
Project description:Understanding of the comparative bleeding risks of oral anticoagulant (OAC) therapies for the primary treatment of venous thromboembolism (VTE) is limited. Therefore, among anticoagulant-naïve VTE patients, we conducted comparisons of apixaban, rivaroxaban and warfarin on the rate of hospitalised bleeding within 180 days of OAC initation. MarketScan databases for the time-period from 2011 to 2016 were used and, for each OAC comparison, new users were matched with up to five initiators of a different OAC. The final analysis included 83 985 VTE patients, who experienced 1944 hospitalised bleeding events. In multivariable-adjusted Cox regression models, rate of hospitalised bleeding was lower among new users of apixaban when compared to new users of rivaroxaban [hazard ratio (95% confidence interval) 0·58 (0·41-0·80)] or warfarin [0·68 (0·50-0·92)]. Overall, the hospitalised bleeding rate was similar when comparing new users of rivaroxaban to new users of warfarin [0·98 (0·68-1·11)], though there was some suggestion that rivaroxaban was associated with lower bleeding risk among younger individuals. Findings from this large real-world population concur with results from the randomised trial which found lower bleeding risk with apixaban versus warfarin and, for the first time, reveal a lower risk of bleeding in a comparison of apixaban versus rivaroxaban.
Project description:The nonvitamin K antagonist oral anticoagulants have recently become available as an alternative to warfarin as stroke prophylaxis in atrial fibrillation, but data on real-life patient experience, including bleeding risk, are lacking. Our objective was to compare major bleeding events and nonpersistence between the nonvitamin K antagonist oral anticoagulant apixaban and other nonvitamin K antagonist oral anticoagulants (dabigatran and rivaroxaban) and warfarin in a contemporary, nation-wide cohort of patients with nonvalvular atrial fibrillation.Of 54 321 patients (median age, 73 years; 56% male; mean CHA2DS2-VASc score, 2.9), 7963, 6715, 15 413, and 24 230 patients initiated apixaban, rivaroxaban, dabigatran, and warfarin, respectively. Apixaban and rivaroxaban initiators were older, less often male, with higher HAS-BLED and CHA2DS2-VASc scores compared with dabigatran and warfarin initiators. A total of 2418 patients (4.5%) experienced a major bleeding event over all available follow-up. In this period, rivaroxaban (hazard ratio [HR] [95% CI], 1.49 [1.27-1.77]), dabigatran (HR, 1.17 [1.00-1.38]), and warfarin (HR, 1.23 [1.05-1.43]) users were significantly more likely to bleed than apixaban users. Findings were similar when restricted to the first 30 days after OAC initiation. Risk of nonpersistence was higher for dabigatran (HR, 1.45 [1.33-1.59]) and warfarin initiators (HR, 1.22 [1.12-1.33]), but not for rivaroxaban initiators (HR, 1.07 [0.96-1.20]) compared with apixaban initiators.In a real-world cohort of nonvalvular atrial fibrillation patients, apixaban had a lower adjusted major bleeding risk compared with rivaroxaban, dabigatran, and warfarin. Apixaban had a lower risk of nonpersistence compared with dabigatran and warfarin and similar risk compared with rivaroxaban.
Project description:Direct oral anticoagulants (DOACs) have low risk of intracranial hemorrhage compared to warfarin. We sought to clarify the different mechanisms responsible for suppression of bleeding events using the Total Thrombus-formation Analysis System (T-TAS), a flow-microchip chamber with thrombogenic surfaces. Blood samples were obtained at Off- and On-anticoagulant (trough) from 120 consecutive patients with atrial fibrillation (warfarin; n = 29, dabigatran; n = 19, rivaroxaban; n = 47, apixaban; n = 25), which were used for T-TAS to compute the area under the curve (AUC) (AR10-AUC30) in the AR chip, and to measure plasma concentrations of DOACs at On-anticoagulant. In addition, the two-dimensional area covered by thrombi (%) in the capillary was analyzed every 3 minutes after sample applications. The AR10-AUC30 correlated weakly and negatively with plasma concentrations of DOACs, and the levels at On-anticoagulant were lower in all groups than at Off-anticoagulant. AR10-AUC30 levels at Off- and On-anticoagulant were identical among the groups. The thrombi areas in early phase were significantly larger in rivaroxaban and apixaban than warfarin and dabigatran groups. The findings suggested that visual analysis of the AR-chip can identify the differential inhibitory patterns of warfarin and DOACs on thrombus formation under flow condition.
Project description:<h4>Objective</h4>To investigate the associations between direct oral anticoagulants (DOACs) and risks of bleeding, ischaemic stroke, venous thromboembolism, and all cause mortality compared with warfarin.<h4>Design</h4>Prospective open cohort study.<h4>Setting</h4>UK general practices contributing to QResearch or Clinical Practice Research Datalink.<h4>Participants</h4>132?231 warfarin, 7744 dabigatran, 37?863 rivaroxaban, and 18?223 apixaban users without anticoagulant prescriptions for 12 months before study entry, subgrouped into 103?270 patients with atrial fibrillation and 92?791 without atrial fibrillation between 2011 and 2016.<h4>Main outcome measures</h4>Major bleeding leading to hospital admission or death. Specific sites of bleeding and all cause mortality were also studied.<h4>Results</h4>In patients with atrial fibrillation, compared with warfarin, apixaban was associated with a decreased risk of major bleeding (adjusted hazard ratio 0.66, 95% confidence interval 0.54 to 0.79) and intracranial bleeding (0.40, 0.25 to 0.64); dabigatran was associated with a decreased risk of intracranial bleeding (0.45, 0.26 to 0.77). An increased risk of all cause mortality was observed in patients taking rivaroxaban (1.19, 1.09 to 1.29) or on lower doses of apixaban (1.27, 1.12 to 1.45). In patients without atrial fibrillation, compared with warfarin, apixaban was associated with a decreased risk of major bleeding (0.60, 0.46 to 0.79), any gastrointestinal bleeding (0.55, 0.37 to 0.83), and upper gastrointestinal bleeding (0.55, 0.36 to 0.83); rivaroxaban was associated with a decreased risk of intracranial bleeding (0.54, 0.35 to 0.82). Increased risk of all cause mortality was observed in patients taking rivaroxaban (1.51, 1.38 to 1.66) and those on lower doses of apixaban (1.34, 1.13 to 1.58).<h4>Conclusions</h4>Overall, apixaban was found to be the safest drug, with reduced risks of major, intracranial, and gastrointestinal bleeding compared with warfarin. Rivaroxaban and low dose apixaban were, however, associated with increased risks of all cause mortality compared with warfarin.
Project description:To assess the risk of liver injury hospitalisation in patients with atrial fibrillation (AF) after initiation of direct oral anticoagulants (DOACs) or warfarin and to determine predictors of liver injury hospitalisation in this population.We studied 113?717 patients (mean age 70, 39% women) with AF included in the MarketScan Commercial and Medicare Supplemental databases with a first prescription for oral anticoagulation after 4 November 2011, followed through 31 December 2014. Of these, 56?879 initiated warfarin, 17?286 initiated dabigatran, 30?347 initiated rivaroxaban and 9205 initiated apixaban. Liver injury hospitalisation and comorbidities were identified from healthcare claims.During a median follow-up of 12?months, 960 hospitalisations with liver injury were identified. Rates of liver injury hospitalisation (per 1000 person-years) by oral anticoagulant were 9.0 (warfarin), 4.0 (dabigatran), 6.6 (rivaroxaban) and 5.6 (apixaban). After multivariable adjustment, liver injury hospitalisation rates were lower in initiators of DOACs compared with warfarin: HR (95% CI) of 0.57 (0.46 to 0.71), 0.88 (0.75 to 1.03) and 0.70 (0.50 to 0.97) for initiators of dabigatran, rivaroxaban, and apixaban, respectively (vs. warfarin). Compared with dabigatran initiators, rivaroxaban initiators had a 56% increased risk of liver injury hospitalisation (HR 1.56, 95% CI 1.22 to 1.99). In addition to type of anticoagulant, prior liver, gallbladder and kidney disease, cancer, anaemia, heart failure and alcoholism significantly predicted liver injury hospitalisation. A predictive model including these variables had adequate discriminative ability (C-statistic 0.67, 95% CI 0.64 to 0.70).Among patients with non-valvular AF, DOACs were associated with lower risk of liver injury hospitalisation compared with warfarin, with dabigatran showing the lowest risk.
Project description:<h4>Background</h4>Clinical trials have demonstrated that direct oral anticoagulants (DOACs) are at least non-inferior to warfarin in reducing the risk of stroke/systemic embolism (SE) among patients with non-valvular atrial fibrillation (NVAF), but the comparative risk of major bleeding varies between DOACs and warfarin. Using US Department of Defense (DOD) data, this study compared the risk of stroke/SE and major bleeding for DOACs relative to warfarin.<h4>Methods</h4>Adult patients with ?1 pharmacy claim for apixaban, dabigatran, rivaroxaban, or warfarin from 01 Jan 2013-30 Sep 2015 were selected. Patients were required to have ?1 medical claim for atrial fibrillation during the 12-month baseline period. Patients with a warfarin or DOAC claim during the 12-month baseline period were excluded. Each DOAC cohort was matched to the warfarin cohort using propensity score matching (PSM). Cox proportional hazards models were conducted to evaluate the risk of stroke/SE and major bleeding of each DOAC vs warfarin.<h4>Results</h4>Of 41,001 identified patients, there were 3691 dabigatran-warfarin, 8226 rivaroxaban-warfarin, and 7607 apixaban-warfarin matched patient pairs. Apixaban was the only DOAC found to be associated with a significantly lower risk of stroke/SE (hazard ratio [HR]: 0.55; 95% confidence interval [CI]: 0.39, 0.77; p?<?0.001) and major bleeding (HR: 0.65; 95% CI: 0.53, 0.80; p?<?0.001) compared to warfarin. Dabigatran and rivaroxaban initiation were associated with similar risk of stroke/SE (dabigatran: HR: 0.68; 95% CI: 0.43, 1.07; p?=?0.096; rivaroxaban: HR: 0.83; 95% CI: 0.64, 1.09; p?=?0.187) and major bleeding (dabigatran: HR: 1.05; 95% CI: 0.79, 1.40; p?=?0.730; rivaroxaban: HR: 1.07; 95% CI: 0.91, 1.27; p?=?0.423) compared to warfarin.<h4>Conclusion</h4>Among NVAF patients in the US DOD population, apixaban was associated with significantly lower risk of stroke/SE and major bleeding compared to warfarin. Dabigatran and rivaroxaban were associated with similar risk of stroke/SE and major bleeding compared to warfarin.