Risk of gastrointestinal bleeding associated with oral anticoagulants: population based retrospective cohort study

Difference between the Upper and the Lower Gastrointestinal Bleeding in Patients Taking Nonvitamin K Oral Anticoagulants

Nonvitamin K oral anticoagulants (NOACs) sometimes cause hemorrhage, and the gastrointestinal tract is a common site of involvement. However, clinical characteristics of gastrointestinal bleeding (GIB) during NOAC therapy have not been fully elucidated. We studied 658 patients who were prescribed dabigatran, rivaroxaban, or apixaban between April 2011 and November 2015. Medical charts were reviewed to examine whether clinically relevant bleeding (Bleeding Academic Research Consortium criteria type 2 or greater) developed. The incidence of GIB was 2.0%/year, and one-third was from the upper GI. Among all hemorrhagic events, GIB was the most common cause. The extent of bleeding from the GI tract, particularly the upper GI tract, was more serious than bleeding from the other site. Multiple regression analysis showed that both past digestive ulcer and absence of concomitant proton pump inhibitors were significantly associated with the incidence of upper GIB, while concomitant nonsteroidal anti-inflammatory drugs, dual antiplatelets, and past GIB were significant factors regarding lower GIB. GIB was common and serious in patients taking NOACs. Upper GIB tended to become more serious than lower GIB. Proton pump inhibitors seem to be key drugs for preventing upper GIB during NOAC therapy.

Major Bleeding Risk During Anticoagulation with Warfarin, Dabigatran, Apixaban, or Rivaroxaban in Patients with Nonvalvular Atrial Fibrillation

BACKGROUND

The use of non-vitamin K oral anticoagulants (NOACs) has increased steadily following marketing approval; however, their relative safety in nonvalvular atrial fibrillation (NVAF) patients in real-world clinical practice remains unclear.

OBJECTIVE

To compare the risk of major bleeding during anticoagulation therapy between warfarin and NOACs.

METHODS

This retrospective cohort study analyzed administrative claims data on new NVAF users of warfarin, dabigatran, apixaban, or rivaroxaban in routine clinical care from November 2010 to February 2015 in a commercially insured population in the United States. The primary outcome was time to first major bleeding event requiring hospitalization. Patients were followed until discontinuation or switch of anticoagulants, health plan disenrollment, death, or end of study. All patient characteristics were balanced after propensity score inverse probability of treatment (IPT) weighting. Event rates by type of anticoagulant exposure were compared using IPT-weighted Cox proportional hazards models.

RESULTS

The study cohort comprised 44,057 patients who used warfarin (n = 23,431), dabigatran (n = 8,539), apixaban (n = 3,689), and rivaroxaban (n = 8,398). Overall mean (SD) age was 70 (12) years, and 41% of the patients were women. A total of 2,337 major bleeding events occurred during 36,636.2 person-years of follow-up. The unadjusted rate of major bleeding with warfarin was 6.0 per 100 person-years versus 2.8 with dabigatran, 3.3 with apixban, and 5.0 with rivaroxaban. Relative to warfarin, major bleeding risk was lower with dabigatran (HR = 0.67, 95% CI = 0.60-0.76) and apixaban (HR = 0.52, 95% CI = 0.41-0.67). Compared with rivaroxaban, major bleeding risk was also lower with dabigatran (HR = 0.67, 95% CI = 0.58-0.78) and apixaban (HR = 0.52, 95% CI = 0.40-0.68). Major bleeding risk was similar for rivaroxaban and warfarin. Relative to apixaban, dabigatran was associated with a significantly higher risk of major gastrointestinal bleeding (HR = 1.43, 95% CI = 1.09-1.88).

CONCLUSIONS

Study results were consistent with safety findings from pivotal clinical trials comparing NOACs with warfarin and added the perspective of a large real-world observational study that compared bleeding risks associated with NOACs during anticoagulation therapy. Apixaban and dabigatran were associated with lower major bleeding risk compared with warfarin or rivaroxaban; however, apixaban had a lower risk of major gastrointestinal bleeding than dabigatran. These findings can help inform the choice of an optimal agent, which must balance effectiveness and bleeding risk in complex patients.

DISCLOSURES

This study was funded by Anthem. Adeboyeje, Sylwestrzak, and Barron are employees of HealthCore, a wholly owned and independently operated subsidiary of Anthem. White, Rosenberg, Abarca, and Crawford are employees of Anthem. Study concept and design were primarily contributed by Adeboyeje and Sylwestrzak, along with the other authors. Adeboyeje took the lead in data collection, along with Sylwestrzak and Barron. Data interpretation was performed primarily by Rosenberg, Crawford, and Redberg, with assistance from the other authors. The manuscript was written by all the authors and revised primarily by White, Abarca, and Redberg, along with the other authors.

Direct Oral Anticoagulants Versus Vitamin K Antagonists in Real-life Patients With Atrial Fibrillation. A Systematic Review and Meta-analysis

INTRODUCTION AND OBJECTIVES

To assess the effectiveness of direct oral anticoagulants vs vitamin K antagonists in real-life patients with atrial fibrillation.

METHODS

A systematic review was performed according to Cochrane methodological standards. The results were reported according to the PRISMA statement. The ROBINS-I tool was used to assess risk of bias.

RESULTS

A total of 27 different studies publishing data in 30 publications were included. In the studies with a follow-up up to 1 year, apixaban (HR, 0.93; 95%CI, 0.71-1.20) and dabigatran (HR, 0.95; 95%CI, 0.80-1.13) did not significantly reduce the risk of ischemic stroke vs warfarin, whereas rivaroxaban significantly reduced this risk (HR, 0.83; 95%CI, 0.73-0.94). Apixaban (HR, 0.66; 95%CI, 0.55-0.80) and dabigatran (HR, 0.83; 95%CI, 0.70-0.97) significantly reduced the major bleeding risk vs warfarin, but not rivaroxaban (HR, 1.02; 95%CI, 0.95-1.10), although with a high statistical heterogeneity among studies. Apixaban (HR, 0.56; 95%CI, 0.42-0.73), dabigatran (HR, 0.45; 95%CI, 0.39-0.51), and rivaroxaban (HR, 0.66; 95%CI, 0.49-0.88) significantly reduced the risk of intracranial bleeding vs warfarin. Reduced doses of direct oral anticoagulants were associated with a slightly better safety profile, but with a marked reduction in stroke prevention effectiveness.

CONCLUSIONS

Data from this meta-analysis suggest that, vs warfarin, the stroke prevention effectiveness and bleeding risk of direct oral anticoagulants may differ in real-life patients with atrial fibrillation.

Real-world comparison of all-cause hospitalizations, hospitalizations due to stroke and major bleeding, and costs for non-valvular atrial fibrillation patients prescribed oral anticoagulants in a US health plan

AIMS

To compare the risk of all-cause hospitalization and hospitalizations due to stroke/systemic embolism (SE) and major bleeding, as well as associated healthcare costs for non-valvular atrial fibrillation (NVAF) patients initiating apixaban, dabigatran, rivaroxaban, or warfarin.

MATERIALS AND METHODS

NVAF patients initiating apixaban, dabigatran, rivaroxaban, or warfarin were selected from the OptumInsight Research Database from January 1, 2013-September 30, 2015. Propensity score matching (PSM) was performed between apixaban and each oral anticoagulant. Cox models were used to estimate the risk of stroke/SE and major bleeding. Generalized linear and 2-part models were used to compare healthcare costs.

RESULTS

Of the 47,634 eligible patients, 8,328 warfarin-apixaban pairs, 3,557 dabigatran-apixaban pairs, and 8,440 rivaroxaban-apixaban pairs were matched. Compared to apixaban, warfarin patients were associated with a significantly higher risk of all-cause (hazard ratio [HR] = 1.30; 95% confidence interval [CI] = 1.21-1.40) as well as stroke/SE-related (HR = 1.60; 95% CI = 1.23-2.07) and major bleeding-related (HR = 1.95; 95% CI = 1.60-2.39) hospitalization; rivaroxaban patients were associated with a higher risk of all-cause (HR = 1.15; 95% CI = 1.07-1.24) and major bleeding-related hospitalization (HR = 1.71; 95% CI = 1.39-2.10); and dabigatran patients were associated with a higher risk of major bleeding hospitalization (HR = 1.46, 95% CI = 1.02-2.10). Warfarin patients had significantly higher major bleeding-related and total all-cause healthcare costs compared to apixaban patients. Rivaroxaban patients had significantly higher major bleeding-related costs compared to apixaban patients. No significant results were found for the remaining comparisons.

LIMITATIONS

No causal relationships can be concluded, and unobserved confounders may exist in this retrospective database analysis.

CONCLUSIONS

This study demonstrated a significantly higher risk of hospitalization (all-cause, stroke/SE, and major bleeding) associated with warfarin, a significantly higher risk of major bleeding hospitalization associated with dabigatran or rivaroxaban, and a significantly higher risk of all-cause hospitalization associated with rivaroxaban compared to apixaban. Lower major bleeding-related costs were observed for apixaban patients compared to warfarin and rivaroxaban patients.

Risk of hair loss with different antidepressants: a comparative retrospective cohort study

The aim of this study was to quantify the risk of hair loss with different antidepressants. A retrospective cohort study design using a large health claims database in the USA from 2006 to 2014 was utilized. A cohort of new user and mutually exclusive users of fluoxetine, fluvoxamine, sertraline, citalopram, escitalopram, paroxetine, duloxetine, venlafaxine, desvenlafaxine, and bupropion were followed to the first diagnosis of alopecia. The cohort was comprised of 1 025 140 new users of fluoxetine, fluvoxamine, sertraline, citalopram, escitalopram, paroxetine, duloxetine, venlafaxine, desvenlafaxine, and bupropion, with sertraline the most commonly prescribed (N=190 227) and fluvoxamine (N=3010) the least prescribed. Compared with bupropion, all other antidepressants had a lower risk of hair loss, with fluoxetine and paroxetine having the lowest risk [hazard ratio (HR)=0.68, 95% confidence interval (CI): 0.63-0.74, HR=0.68, 95% CI: 0.62-0.74, respectively] and fluvoxamine having the highest risk (HR=0.93, 95% CI: 0.64-1.37). Compared with fluoxetine, bupropion had the highest risk of hair loss (HR=1.46, 95% CI: 1.35-1.58, number needed to harm=242 for 2 years) and paroxetine had the lowest risk (HR=0.99, 95% CI: 0.90-1.09). The results of this large population-based cohort study suggest an increase in the risk of hair loss with bupropion compared with selective serotonin reuptake inhibitors and selective norepinephrine reuptake inhibitors, whereas paroxetine had the lowest risk.

Bleeding Risk of Warfarin and Direct Oral Anticoagulants in Younger Population: A Historical Cohort Study Using a Japanese Claims Database

A historical cohort analysis of the Japan medical data center (JMDC) claims databases was performed to compare the incidence rates of bleeding events with warfarin (WF) versus direct oral anticoagulant (DOAC) treatment in patients with non-valvular atrial fibrillation. The aim of this study is to clarify the risk factors for bleeding events in younger patients newly treated with WF or DOAC in clinical practice setting. Patients who newly initiated WF or DOAC treatment from April 2012 to March 2015 were selected from the JMDC claims database. A 1:1 propensity score matching analysis was used for new users of WF or DOAC. Kaplan-Meier curves were generated to depict the time to bleeding event (total bleeding events, gastrointestinal hemorrhage, and intracranial hemorrhage) during the follow-up period. Cox proportional regression models were used to estimate the hazard ratios for total bleeding events caused by oral anticoagulants. Overall, 2,046 patients (503 WF and 1,543 DOAC) were included. After applying propensity score matching, Kaplan-Meier analysis of the WF and DOAC groups displayed comparable incidences of total bleeding events, gastrointestinal hemorrhage, and intracranial hemorrhage. Cox proportional hazards modeling showed that the use of WF was not associated with total bleeding events compared with DOAC (hazard ratio: 1.21, 95% confidence interval: 0.93-1.54, p = 0.15). This historical cohort study using a claims database indicates that the bleeding risk of DOAC was comparable to that of WF in Japanese younger population.

Renal Outcomes in Anticoagulated Patients With Atrial Fibrillation

BACKGROUND

Lifelong oral anticoagulation, either with warfarin or a non-vitamin K antagonist oral anticoagulant (NOAC), is indicated for stroke prevention in most patients with atrial fibrillation (AF). Emerging evidence suggests that NOACs may be associated with better renal outcomes than warfarin.

OBJECTIVES

This study aimed to compare 4 oral anticoagulant agents (apixaban, dabigatran, rivaroxaban, and warfarin) for their effects on 4 renal outcomes: ≥30% decline in estimated glomerular filtration rate (eGFR), doubling of the serum creatinine level, acute kidney injury (AKI), and kidney failure.

METHODS

Using a large U.S. administrative database linked to laboratory results, the authors identified 9,769 patients with nonvalvular AF who started taking an oral anticoagulant agent between October 1, 2010 and April 30, 2016. Inverse probability of treatment weighting was used to balance more than 60 baseline characteristics among patients in the 4 drug cohorts. Cox proportional hazards regression was performed in the weighted population to compare oral anticoagulant agents.

RESULTS

The cumulative risk at the end of 2 years for each outcome was 24.4%, 4.0%, 14.8%, and 1.7% for ≥30% decline in eGFR, doubling of serum creatinine, AKI, and kidney failure, respectively. When the 3 NOACs were pooled, they were associated with reduced risks of ≥30% decline in eGFR (hazard ratio [HR]: 0.77; 95% confidence interval [CI]: 0.66 to 0.89; p < 0.001), doubling of serum creatinine (HR: 0.62; 95% CI: 0.40 to 0.95; p = 0.03), and AKI (HR: 0.68; 95% CI: 0.58 to 0.81; p < 0.001) compared with warfarin. When comparing each NOAC with warfarin, dabigatran was associated with lower risks of ≥30% decline in eGFR and AKI; rivaroxaban was associated with lower risks of ≥30% decline in eGFR, doubling of serum creatinine, and AKI; however, apixaban did not have a statistically significant relationship with any of the renal outcomes.

CONCLUSIONS

Renal function decline is common among patients with AF treated with oral anticoagulant agents. NOACs, particularly dabigatran and rivaroxaban, may be associated with lower risks of adverse renal outcomes than warfarin.

Dabigatran in real-world atrial fibrillation

In the RE-LY clinical trial, dabigatran presented a better effectiveness/ safety profile when compared to warfarin. However, clinical trials are not very representative of the real-world setting. We aimed to assess the performance of dabigatran in real-world patients with atrial fibrillation (AF) by means of a systematic review and meta-analysis of observational comparison studies with vitamin K antagonists (VKA). We searched PubMed, Embase and Scopus databases until November 2015 and selected studies according to the following criteria: observational study performed with nonvalvular AF patients; reporting adjusted hazard ratios (HR) of clinical events in a follow-up period; for dabigatran 75 mg, 110 mg or 150 mg versus VKA. Twenty studies were selected which included 711,298 patients, 210,279 of which were treated with dabigatran and the remaining 501,019 with VKA. Ischaemic stroke incidence was of 1.65 /100 patient-years for dabigatran and 2.85/100 patient-years for VKA (HR 0.86, 95 % confidence interval of 0.74–0.99). Major bleeding rate was 3.93/100 patient-years for dabigatran and 5.61/100 patient-years for VKA (0.79, 0.69–0.89). Risk of mortality (0.73, 0.61–0.87) and intracranial bleeding (0.45, 0.38–0.52) were significantly lower in patients treated with dabigatran when compared to patients on VKA. Risk of gastrointestinal (GI) bleeding was significantly higher in patients treated with dabigatran (1.13, 1.00–1.28). No significant difference was observed in risk of myocardial infarction (0.99, 0.89–1.11). In this combined analysis of real-world observational comparison studies with VKA, dabigatran was associated with a lower risk of ischaemic stroke, major bleeding, intracranial bleeding and mortality, higher risk of GI bleeding and a similar risk of myocardial infarction.

Supplementary Material to this article is available online at www.thrombosis-online.com.

Risk of Gastrointestinal Bleeding in Patients Taking Non-Vitamin K Antagonist Oral Anticoagulants: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

Non-vitamin K antagonist oral anticoagulants (NOACs) are convenient and effective in the prevention and treatment of venous thromboembolism and the prevention of stroke in patients with atrial fibrillation. However, these drugs have been associated with an increased risk of gastrointestinal (GI) bleeding. We conducted a systematic review and meta-analysis to determine the risk of GI bleeding in patients receiving these drugs.

METHODS

We searched the EMBASE, Medline, Cochrane, and ISI Web of knowledge databases through January 2016 for randomized trials that compared NOACs with conventional anticoagulants for approved indications. We conducted a meta-analysis, reporting odds ratios (ORs) with 95% confidence intervals (CIs). The primary outcome was major GI bleeding. Secondary outcomes included clinically relevant nonmajor bleeding and upper and lower GI bleeding. We performed a priori subgroup analyses by individual drug.

RESULTS

Our analysis included a total of 43 randomized trials, comprising 166,289 patients. There was no difference between NOACs and conventional anticoagulants in the risk of major bleeding (1.5% vs 1.3%, respectively; OR, 0.98; 95% CI, 0.80-1.21), clinically relevant nonmajor bleeding (0.6% vs 0.6%, respectively; OR, 0.93; 95% CI, 0.64-1.36), upper GI bleeding (1.5% vs 1.6%, respectively; OR, 0.96; 95% CI, 0.77-1.20), or lower GI bleeding (1.0% vs 1.0%, respectively; OR, 0.88; 95% CI, 0.67-1.15). Dabigatran (2.0% vs 1.4%, respectively; OR, 1.27; 95% CI, 1.04-1.55) and rivaroxaban (1.7% vs 1.3%, respectively; OR, 1.40; 95% CI, 1.15-1.70) were associated with increased odds of major GI bleeding compared with conventional anticoagulation, whereas no difference was found for apixaban (0.6% vs 0.7%, respectively; OR, 0.81; 95% CI, 0.64-1.02) or edoxaban (1.9% vs 1.6%, respectively; OR, 0.93; 95% CI, 0.78-1.11). These subgroup findings were not observed in other sensitivity analyses.

CONCLUSIONS

In a systematic review and meta-analysis, we found risk of major GI bleeding to be similar between NOACs and conventional anticoagulation. Dabigatran and rivaroxaban, however, may be associated with increased odds of major GI bleeding. Further high-quality studies are needed to characterize GI bleeding risk among NOACs.

Bleeding-related hospital admissions and 30-day readmissions in patients with non-valvular atrial fibrillation treated with dabigatran versus warfarin

Essentials Bleeding is a common cause of hospital admission and readmission in oral anticoagulant users. Patients with dabigatran and warfarin were included to assess hospital admission risk. Dabigatran users had a higher risk of 30-day readmission with bleeding than warfarin users. Close monitoring following hospital discharge for dabigatran-related bleeding is warranted.

SUMMARY

Background Reducing 30-day hospital readmission is a policy priority worldwide. Warfarin-related bleeding is among the most common cause of hospital admissions as a result of adverse drug events. Compared with warfarin, dabigatran achieves a full anticoagulation effect more quickly following its initiation; hence it may lead to early-onset bleeds. Objectives To compare the incidence of bleeding-related hospital admissions and 30-day readmissions with dabigatran vs. warfarin in patients with non-valvular atrial fibrillation (NVAF). Methods This was a retrospective cohort study using a population-wide database managed by the Hong Kong Hospital Authority. Patients newly diagnosed with NVAF from 2010 through to 2014 and prescribed dabigatran or warfarin were 1:1 matched by propensity score. The incidence rate of hospital admission with bleeding (a composite of gastrointestinal bleeding, intracranial hemorrhage and bleeding at other sites) was assessed. Results Among the 51 946 patients with NVAF, 8309 users of dabigatran or warfarin were identified, with 5160 patients matched by propensity score. The incidence of first hospitalized bleeding did not differ significantly between groups (incidence rate ratio, 0.92; 95% confidence interval [CI], 0.66-1.28). Among patients who were continuously prescribed their initial anticoagulants upon discharge, dabigatran use was associated with a higher risk of 30-day readmission with bleeding over warfarin (adjusted hazard ratio, 2.87; 95%CI, 1.10-7.43). Conclusion When compared with warfarin, dabigatran was associated with a comparable incidence of first hospital admission but a higher risk of 30-day redmission with respect to bleeding. Close early monitoring of patients initiated on dabigatran following hospital discharge for bleeding is warranted.

Systemic Octreotide Therapy in Prevention of Gastrointestinal Bleeds Related to Arteriovenous Malformations and Obscure Etiology in Atrial Fibrillation

OBJECTIVES

The present study describes the use of octreotide (OCT) in patients with atrial fibrillation (AF) receiving oral anticoagulation (OAC) who have gastrointestinal (GI) bleeding related to arteriovenous malformations (AVMs), as well as its effect on OAC tolerance and subsequent rebleeding.

BACKGROUND

AVMs cause significant GI bleeding, especially in patients with AF who are receiving OAC for stroke prevention. OCT has been shown to minimize recurrent GI bleeds related to AVMs.

METHODS

In a multicenter, observational study, 38 AF patients with contraindications to OAC because of AVM-related GI bleeding were started on 100 μg of subcutaneous OCT twice daily. OAC was resumed in all patients within 48 h. Incidence of recurrent GI bleeds was calculated, and hemoglobin levels were recorded at enrollment and at 3 and 6 months' follow-up.

RESULTS

After a median follow-up of 8 months, 36 patients (mean age 69 ± 8.0 years; mean CHA₂DS₂-VASc score 3 ± 1 and mean HAS-BLED score 3 ± 1) were available for analysis. All were able to successfully resume OAC, and 28 of 36 (78%) remained on OAC at the conclusion of the study, whereas 8 underwent left atrial appendage closure with subsequent OAC discontinuation. No systemic thromboembolic events occurred in follow-up. Of the 28 patients who continued receiving OAC, 19 (68%) were free of recurrent GI bleed, 4 had minor GI bleeds, 4 required transfusion, and 1 required colectomy for GI bleeding. Mean hemoglobin levels in all patients receiving OAC were significantly higher at 3- and 6-month follow-up than at baseline (p < 0.001).

CONCLUSIONS

Subcutaneous OCT therapy is an attractive option in AF patients receiving OAC who have AVM-related GI bleeds. It allows successful reinitiation of OAC as a bridge to left atrial appendage exclusion or short-term relief from bleeding.

Non-Vitamin K Antagonist Oral Anticoagulant Dosing in Patients With Atrial Fibrillation and Renal Dysfunction

BACKGROUND

Dose reduction of non-vitamin K antagonist oral anticoagulants (NOACs) is indicated in patients with atrial fibrillation (AF) with renal impairment. Failure to reduce the dose in patients with severe kidney disease may increase bleeding risk, whereas dose reductions without a firm indication may decrease the effectiveness of stroke prevention.

OBJECTIVES

The goal of this study was to investigate NOAC dosing patterns and associated outcomes, i.e., stroke (ischemic stroke and systemic embolism) and major bleeding in patients treated in routine clinical practice.

METHODS

Using a large U.S. administrative database, 14,865 patients with AF were identified who initiated apixaban, dabigatran, or rivaroxaban between October 1, 2010, and September 30, 2015. We examined use of a standard dose in patients with a renal indication for dose reduction (potential overdosing) and use of a reduced dose when the renal indication is not present (potential underdosing). Cox proportional hazards regression was performed in propensity score-matched cohorts to investigate the outcomes.

RESULTS

Among the 1,473 patients with a renal indication for dose reduction, 43.0% were potentially overdosed, which was associated with a higher risk of major bleeding (hazard ratio: 2.19; 95% confidence interval: 1.07 to 4.46) but no statistically significant difference in stroke (3 NOACs pooled). Among the 13,392 patients with no renal indication for dose reduction, 13.3% were potentially underdosed. This underdosing was associated with a higher risk of stroke (hazard ratio: 4.87; 95% confidence interval: 1.30 to 18.26) but no statistically significant difference in major bleeding in apixaban-treated patients. There were no statistically significant relationships in dabigatran- or rivaroxaban-treated patients without a renal indication.

CONCLUSIONS

In routine clinical practice, prescribed NOAC doses are often inconsistent with drug labeling. These prescribing patterns may be associated with worse safety with no benefit in effectiveness in patients with severe kidney disease and worse effectiveness with no benefit in safety in apixaban-treated patients with normal or mildly impaired renal function.

New oral anticoagulant prescription rate and risk of bleeding in an Italian region

PURPOSE

The purpose of this study was to measure the prescription rate of new oral anticoagulants (NOACs) and to investigate whether there is an increased risk of bleeding associated with these medications in the 1 220 000-inhabitant Italian region Friuli Venezia Giulia.

METHODS

The administrative data of the Regional Health Information System, linkable with each other at the individual patient level through an anonymous stochastic key, were used as the source of information. Prescription rates for rivaroxaban, dabigatran, and apixaban were calculated in the regional population in 2014 and 2015, also stratified by age class and gender. A case-crossover analysis with pair-matched interval approach and a case-time-control analysis were conducted to assess the risk of hospitalization with a diagnosis of bleeding and prescription of NOACs.

RESULTS

In the regional population ≥18 years of age, 1626 NOACs prescriptions per 100 000 population-years were filled in 2014 and 3370 in 2015. Prescription rate increased with age and was greater in males than in females. Overall, being a current NOACs user was not associated with the risk of hospitalization for bleeding compared to being a nonuser. A nonsignificant increase in risk was observed among patients with low prescription intensity.

CONCLUSIONS

This study showed an increasing time trend in NOACs prescriptions NOACs in Friuli Venezia Giulia. In this Italian population, NOACs users had no significantly increased risk of bleeding events as compared with nonusers.

A single institution’s experience with using dabigatran, rivaroxaban and warfarin for prevention of thromboembolism in atrial fibrillation

Background:

Although non-vitamin K antagonist oral anticoagulants (NOACs) are approved for stroke prevention in atrial fibrillation (AF) patients, their use in the local clinical setting has not been well studied. This study aims to evaluate the clinical outcomes of dabigatran, rivaroxaban and warfarin in a tertiary hospital in Singapore.

Methods:

This is a retrospective cohort study with one-year follow-up. A total of 383 patients recruited between June 2011 and December 2014 were studied. Incidents of stroke, systemic embolism and clinically relevant bleeding events were compared between dabigatran, rivaroxaban and warfarin.

Results:

Stroke rates were 5.47% per year with warfarin, 7.27% per year with dabigatran (HR=1.32; 95% CI 0.48−3.64; p=0.591) and 2.76% per year with rivaroxaban (HR=0.49; 95% CI 0.14−1.69; p=0.261). The warfarin group had significantly higher incidence of minor bleeding (62.4% vs 3.64% for dabigatran vs 13.79% for rivaroxaban; p<0.001), major bleeding (3.91% for warfarin, 0.91% for dabigatran, 0% for rivaroxaban; p=0.028) and other adverse events (51.18% for warfarin, 3.64% for dabigatran, 8.28% for rivaroxaban; p<0.001). Incidence of dyspepsia was higher in both NOAC groups compared to warfarin (0% for warfarin, 7.27% for dabigatran, 5.52% for rivaroxaban; p=0.003).

Conclusion:

Stroke and venous thromboembolism rates after one year were comparable among dabigatran, rivaroxaban and warfarin. Warfarin was associated with more bleeding and adverse events while both NOACs were associated with higher rates of dyspepsia. Further study is needed to assess the clinical benefit of NOACs in the Singaporean population.

Safety profile of the direct oral anticoagulants: an analysis of the WHO database of adverse drug reactions

AIM

Direct oral anticoagulants (DOACs) have shown noninferiority to warfarin for stroke prevention in nonvalvular atrial fibrillation (AF) and a more promising safety profile. Unanswered safety aspects remain to be addressed and available evidence on the risk associated with these drugs are conflicting. In order to contribute to the debate on their safety profile, we conducted a comparative analysis of the reports of suspected adverse drug reactions (ADRs) associated with DOACs in VigiBase.

METHODS

Study based on reports of suspected ADRs held in VigiBase as at December 2014, in which a DOAC or warfarin were administered in patients with nonvalvular AF and listed as suspected/interacting drugs. Medical Dictionary for Regulatory Activities was used to classify ADRs. Reporting odds ratio (ROR) with 95% confidence interval were calculated. Results with P ≤ 0.05 were statistically significant.

RESULTS

We retrieved 32 972 reports. We identified 204 ADRs with a ROR >1 (P ≤ 0.05) and we focused on 105 reactions. Positive ROR emerged for DOACs and gastrointestinal haemorrhage compared with warfarin [(1.6 (1.47-1.75)], but no disproportionality with cerebral haemorrhage was found [0.31 (0.28-0.34)]. We identified other potential signals that have not been associated with DOACs previously.

CONCLUSIONS

As well as premarketing authorization clinical trial studies, we found a reduced risk of intracranial haemorrhage, but an increased risk of gastrointestinal haemorrhage in patients treated with DOACs compared to warfarin. We provide new data and we highlight several differences between the three novel oral anticoagulants, in the rate and type of ADRs occurred.

Risk of gastrointestinal bleeding during anticoagulant treatment

INTRODUCTION

Gastrointestinal bleeding (GIB) is a major problem in patients on oral anticoagulation therapy. This issue has become even more pressing since the introduction of direct oral anticoagulants (DOACs) in 2009. Areas covered: Here we review current evidence related to GIB associated with oral anticoagulants, focusing on randomized controlled trials, meta-analyses, and post-marketing observational studies. Dabigatran 150 mg twice daily and rivaroxaban 20 mg once daily increase the risk of GIB compared to warfarin. The risk increase with edoxaban is dose-dependent, while apixaban shows apparently, no increased risk. We summarize what is known about GIB risk factors for individual anticoagulants, the location of GIB in patients taking these compounds, and prevention strategies that lower the risk of GIB. Expert opinion: Recently there has been an important shift in the clinical presentation of GIB. Specifically, upper GIB has decreased with the decreased incidence of peptic ulcers due to the broad use of proton pump inhibitors and the decreased prevalence of H. pylori infections. In contrast, the incidence of lower GIB has increased, due in part to colonic diverticular bleeding and angiodysplasia in the elderly. In this population, the addition of oral anticoagulation therapy, especially DOACs, seems to increase the risk of lower GIB.

ANMCO Position Paper: direct oral anticoagulants for stroke prevention in atrial fibrillation: clinical scenarios and future perspectives

It is now 4 years since the introduction of the new direct oral anticoagulants into clinical practice. Therefore, the Italian Association of Hospital Cardiologists (ANMCO) has deemed necessary to update the previous position paper on the prevention of thrombo-embolic complications in patients with non-valvular atrial fibrillation, which was published in 2013. All available scientific evidence has been reviewed, focusing on data derived from both clinical trials and observational registries. In addition, all issues relevant to the practical clinical management of oral anticoagulation with the new direct inhibitors have been considered. Specific clinical pathways for optimal use of oral anticoagulation with the new directly acting agents are also developed and proposed for clinical implementation. Special attention is finally paid to the development of clinical algorithms for medium and long-term follow-up of patients treated with new oral direct anticoagulants.

A Comparison of the Rate of Gastrointestinal Bleeding in Patients Taking Non-Vitamin K Antagonist Oral Anticoagulants or Warfarin

OBJECTIVES

Early reports suggested that the risk of gastrointestinal bleeding (GIB) was higher for patients on non-vitamin K antagonist oral anticoagulants (NOACs) than for those on warfarin. We compared the incidence of GIB in our patients on NOACs with those on warfarin.

METHODS

We used our VA pharmacy database to identify patients taking NOACs (dabigatran, rivaroxaban, and apixaban) or warfarin between January 2011 and June 2015, and used the VistA system to identify those who were hospitalized for GIB. We included only patients with clinically significant GIB, defined as documented GI blood loss with a hemoglobin drop ≥2 g/dl, hemodynamic instability, and/or need for endoscopic evaluation, angiography, or surgery.

RESULTS

We identified 803 patients on NOACs and 6,263 on warfarin. One hundred and fifty-eight patients on warfarin had GIB (2.5%), compared with only five patients (0.6%) on NOACs (odds ratio=4.13; 95% confidence interval: 1.69-10.09). Blood transfusion for GIB was significantly more common in patients on warfarin than on NOACs (64.6% vs. 20%, P=0.04). Within 90 days of GIB hospitalization, 12 patients (7.6%) in the warfarin group died, whereas there were no deaths in the NOAC group.

CONCLUSIONS

In our patients, the incidence of GIB for those on warfarin was more than four times that for those on NOACs. Blood transfusions for GIB were more common in warfarin patients, and no NOAC patients died of GIB. In contrast to early reports, our findings suggest that the risk of GIB and subsequent complications is considerably lower for patients on NOACs than for patients on warfarin.

Vitamin K antagonists: relative strengths and weaknesses vs. direct oral anticoagulants for stroke prevention in patients with atrial fibrillation

Vitamin K antagonists (VKAs) have been the mainstay of anticoagulation therapy for more than 50 years. VKAs are mainly used for the prevention of stroke in patients with atrial fibrillation (AF) and the treatment and secondary prevention of venous thromboembolism. In the past 5 years, four new agents-the direct factor Xa inhibitors apixaban, edoxaban and rivaroxaban and the direct thrombin inhibitor dabigatran [collectively known as direct oral anticoagulants (DOACs) or non-VKA oral anticoagulants]-have been approved for these and other indications. Despite these new treatment options, the VKA warfarin currently remains the most frequently prescribed oral anticoagulant. The availability of DOACs provides an alternative management option for patients with AF, especially when the treating physician is hesitant to prescribe a VKA owing to associated limitations, such as food and drug interactions, and concerns about bleeding complications. Currently available real-world evidence shows that DOACs have similar or improved effectiveness and safety outcomes compared with warfarin. Treatment decisions on which DOAC is best suited for which patient to maximize safety and effectiveness should take into account not only clinically relevant patient characteristics but also patient preference. This article reviews and highlights real and perceived implications of VKAs for the prevention of stroke in patients with non-valvular AF, with specific reference to their strengths and weaknesses compared with DOACs.

Gastrointestinal bleeding in patients on novel oral anticoagulants: Risk, prevention and management

Novel oral anticoagulants (NOACs), which include direct thrombin inhibitor (dabigatran) and direct factor Xa inhibitors (rivaroxaban, apixaban and edoxaban), are gaining popularity in the prevention of embolic stroke in non-valvular atrial fibrillation as well as in the prevention and treatment of venous thromboembolism. However, similar to traditional anticoagulants, NOACs have the side effects of bleeding, including gastrointestinal bleeding (GIB). Results from both randomized clinical trials and observations studies suggest that high-dose dabigatran (150 mg b.i.d), rivaroxaban and high-dose edoxaban (60 mg daily) are associated with a higher risk of GIB compared with warfarin. Other risk factors of NOAC-related GIB include concomitant use of ulcerogenic agents, older age, renal impairment, Helicobacter pylori infection and a past history of GIB. Prevention of NOAC-related GIB includes proper patient selection, using a lower dose of certain NOACs and in patients with renal impairment, correction of modifiable risk factors, and prescription of gastroprotective agents. Overt GIB can be managed by withholding NOACs followed by delayed endoscopic treatment. In severe bleeding, additional measures include administration of activated charcoal, use of specific reversal agents such as idarucizumab for dabigatran and andexanent alfa for factor Xa inhibitors, and urgent endoscopic management.

Reintroduction of anti-thrombotic therapy after a gastrointestinal haemorrhage: if and when?

Gastrointestinal haemorrhage is a common clinical scenario and, in those using antithrombotic agents, the risk is significantly increased. Management of these patients, in terms of initial resuscitation is well established and numerous guidelines exist in this area. However, few studies have addressed the subsequent dilemma of if and when antithrombotic agents should be reintroduced. Consequently, practice is variable and not necessarily evidenced-based. Overall, for patients that are either anticoagulated or using antiplatelet drugs for secondary prophylaxis, there is a clear benefit to restarting these agents. However, there is limited data to guide when this should occur. For individuals at low risk of re-bleeding, current guidelines suggest single agent aspirin can be continued without interruption, assuming haemostatic control has been confirmed endoscopically. For those at higher bleeding risk, aspirin should be withheld, but reintroduced early (within 3 days of index endoscopy). However, randomised evidence is lacking, as are studies including more modern agents or combined anticoagulant/ antiplatelet regimens. As such, guidance statements are limited and management suggestions must be extrapolated from clinical trials, retrospective studies and data relating specifically to warfarin and aspirin. The intention of this review is to summarise what evidence is available and, where this is lacking, suggest pragmatic management options based on a risk-benefit assessment of thromboembolism and recurrent bleeding.

Reversal of direct oral anticoagulants

An understanding of how to counteract the anticoagulant effect of direct oral anticoagulants is essential in the event of haemorrhage, emergency surgery and overdose. This review summarizes strategies for the reversal of direct oral anticoagulants, including the use of novel agents.

Comparing Stroke and Bleeding with Rivaroxaban and Dabigatran in Atrial Fibrillation: Analysis of the US Medicare Part D Data

BACKGROUND

No studies have directly compared the effectiveness and safety of dabigatran and rivaroxaban using US Medicare data.

OBJECTIVE

Our objective was to compare effectiveness and safety between rivaroxaban 20 mg/dabigatran 150 mg and rivaroxaban 15 mg/dabigatran 75 mg among patients with atrial fibrillation (AF).

METHODS

Using 2010-2013 US Medicare Part D data, we selected patients with AF initiating dabigatran 150/75 mg or rivaroxaban 20/15 mg between 4 November 2011 (when rivaroxaban was approved) and 31 December 2013. Our sample included 7322 patients receiving dabigatran 150 mg, 5799 patients receiving rivaroxaban 20 mg, 1818 receiving dabigatran 75 mg, and 2568 receiving rivaroxaban 15 mg. We followed them until stroke, other thromboembolic events, bleeding, discontinuation or switch of an anticoagulant, death, or 31 December 2013. We constructed Cox proportional hazard models with propensity score weighting to compare clinical outcomes between groups.

RESULTS

There was no difference in the risk of stroke between dabigatran 150 mg and rivaroxaban 20 mg (hazard ratio [HR] 1.05; 95 % confidence interval [CI] 0.97-1.13) or between dabigatran 75 mg and rivaroxaban 15 mg (HR 1.05; 95 % CI 0.94-1.18). Compared with dabigatran 150 mg, rivaroxaban 20 mg was associated with a higher risk of other thromboembolic events (HR 1.28; 95 % CI 1.14-1.44), major bleeding (HR 1.32; 95 % CI 1.17-1.50), and death (HR 1.36; 95 % CI 1.19-1.56). The risk of thromboembolic events other than stroke (HR 1.37; 95 % CI 1.15-1.62), major bleeding (HR 1.51; 95 % CI 1.25-1.82), and death (HR 1.21; 95 % CI 1.04-1.41) was also higher for rivaroxaban 15 mg than for dabigatran 75 mg.

CONCLUSIONS

There was no difference in stroke prevention between rivaroxaban and dabigatran; however, rivaroxaban was associated with a higher risk of thromboembolic events other than stroke, death, and bleeding.

Relationship between Early Physician Follow-Up and 30-Day Readmission after Acute Myocardial Infarction and Heart Failure

Background

Thirty-day readmission rates after acute myocardial infarction (AMI) and heart failure are important patient outcome metrics. Early post-discharge physician follow-up has been promoted as a method of reducing 30-day readmission rates. However, the relationships between early post-discharge follow-up and 30-day readmission for AMI and heart failure are inconclusive. We used nationwide population-based data to examine associations between 7-day physician follow-up and 30-day readmission, and further associations of 7-day same physician (during the index hospitalization and at follow-up) and cardiologist follow-up with 30-day readmission for non-ST-segment-elevation myocardial infarction (NSTEMI) or heart failure.

Methods

We analyzed all patients 18 years or older with NSTEMI and heart failure and discharged from hospitals in 2010 in Taiwan through Taiwan’s National Health Insurance Research Database. Cox proportional hazard models with robust sandwich variance estimates and propensity score weighting were performed after adjustment for patient and hospital characteristics to test associations between 7-day physician follow-up and 30-day readmission.

Results

The study population for NSTEMI and heart failure included 5,008 and 13,577 patients, respectively. Early physician follow-up was associated with a lower hazard ratio of readmission compared with no early physician follow-up for patients with NSTEMI (hazard ratio [HR], 0.47; 95% confidence interval [CI], 0.39–0.57), and for patients with heart failure (HR, 0.54; 95% CI, 0.48–0.60). Same physician follow-up was associated with a reduced hazard ratio of readmission compared with different physician follow-up for patients with NSTEMI (HR, 0.56; 95% CI, 0.48–0.65), and for patients with heart failure (HR, 0.69; 95% CI, 0.62–0.76).

Conclusions

For each condition, patients who have an outpatient visit with a physician within 7 days of discharge have a lower risk of 30-day readmission. Moreover, patients who have an outpatient visit with the same physician within 7 days of discharge have a much lower risk of 30-day readmission.

Risk of Gastrointestinal Bleeding Among Dabigatran Users - A Self Controlled Case Series Analysis

This article aims to evaluate the real world risk of gastrointestinal bleeding among users naïve to dabigatran. We adopted a self-controlled case series design. We sampled 1215 eligible adult participants who were continuous insured users between July 1, 2010 and March 31, 2012 with use of dabigatran and at least one gastrointestinal bleeding episode. We used a conditional Poisson regression to estimate incidence rate ratios. The population consisted of 64.69% of male and 60.25% patients equal to or greater than age 65 at start of observation. After adjustment for time-variant confounders, the incidence rate of gastrointestinal bleeding was similar during dabigatran risk period and non-exposed period (incidence rate ratio [IRR] = 1.01, 95% confidence interval [CI] 0.90, 1.15). There was no significant difference in GI incidence rate between periods of dabigatran and warfarin (IRR = 0.99, 95% CI 0.75-1.31). Among this database of young and healthy participants, dabigatran was not associated with increased incidence rate of GI bleeding compared with non-exposed period among naïve dabigatran users. We did not detect an increased risk of GI bleeding over dabigatran vs warfarin risk period. Along with other studies on safety and effectiveness, this study should help clinicians choose the appropriate anticoagulant for their patients.

Risk-Benefit Profile of Direct-Acting Oral Anticoagulants in Established Therapeutic Indications: An Overview of Systematic Reviews and Observational Studies

Since 2008, the direct-acting oral anticoagulants (DOACs) have expanded the therapeutic options of cardiovascular diseases with recognized clinical and epidemiological impact, such as non-valvular atrial fibrillation (NVAF) and venous thromboembolism (VTE), and also in the preventive setting of orthopedic surgical patients. The large body of evidence, not only from pivotal clinical trials but also from 'real-world' postmarketing observational findings (e.g. analytical epidemiological studies and registry data) gathered to date allow for a first attempt at verifying a posteriori whether or not the pharmacological advantages of the DOACs actually translate into therapeutic innovation, with relevant implications for clinicians, regulators and patients. This review aims to synthesize the risk-benefit profile of DOACs in the aforementioned consolidated indications through an 'evidence summary' approach gathering the existent evidence-based data, particularly systematic reviews with meta-analyses of randomized controlled trials, as well as observational studies, comparing DOACs with vitamin K antagonists. Clinical evidence will be discussed and compared with major international guidelines to identify whether an update is needed. Controversial clinically relevant safety issues will be also examined in order to highlight current challenges and unsettled questions (e.g. actual bleeding risk in susceptible populations). It is anticipated that the large number of publications on NVAF or VTE (44 systematic reviews with meta-analyses and 12 observational studies retained in our analysis) suggests the potential existence of overlapping studies and calls for common criteria to qualitatively and quantitatively assess discordances, thus guiding future research.

Gastrointestinal bleeding and intracranial hemorrhage in concomitant users of warfarin and antihyperlipidemics

BACKGROUND

Drug interactions, particularly those involving warfarin, are a major clinical and public health problem. Minimizing serious bleeding caused by anticoagulants is a recent major focus of the United States (US) Department of Health and Human Services. This study quantified the risk of gastrointestinal bleeding (GIB) and intracranial hemorrhage (ICH) among concomitant users of warfarin and individual antihyperlipidemics.

METHODS

The authors conducted a high-dimensional propensity score-adjusted cohort study of new concomitant users of warfarin and an antihyperlipidemic, among US Medicaid beneficiaries from five states during 1999-2011. Exposure was defined by concomitant use of warfarin plus one of eight antihyperlipidemics. The primary outcome measure was a composite of GIB/ICH within the first 30days of concomitant use. As a secondary outcome measure, GIB/ICH was examined within the first 180days of concomitant use.

RESULTS

Among 236,691 persons newly-exposed to warfarin and an antihyperlipidemic, the crude incidence of GIB/ICH was 13.2 (95% confidence interval 12.7 to 13.8) per 100person-years. Users were predominantly older, female, and Caucasian. Adjusted hazard ratios (aHRs) for warfarin and individual statins were consistent with no association. Warfarin+gemfibrozil was associated with an 80% increased risk of GIB/ICH within the first month of concomitant use (aHR=1.8, 1.4 to 2.4). Warfarin+fenofibrate was associated with a similar increased risk (aHR=1.8, 1.2 to 2.7), yet with an onset during the second month of concomitant use.

CONCLUSIONS

Among warfarin-treated persons, the use of fibrates-but not statins-increases the risk of hospital presentation for GIB/ICH.

Improved persistence with non-vitamin-K oral anticoagulants compared with warfarin in patients with atrial fibrillation: recent Australian experience

OBJECTIVE

Long-term anticoagulant therapy in patients with non-valvular atrial fibrillation (AF) is essential to prevent thromboembolic complications, especially ischemic stroke, but treatment persistence with warfarin is poor. This study examines Australian nationwide persistence in AF patients using a non-vitamin-K oral anticoagulant (NOAC) drug.

RESEARCH DESIGN AND METHODS

We assessed national Pharmaceutical Benefit Scheme records November-December 2013 through March 2015 for prescription of NOAC drugs in a 10% random sample of long-term concession card holders. An historical comparison was made with patients prescribed warfarin in 2008. Key outcome measures were (i) the proportion not filling first repeat prescription and (ii) discontinuation within 12 months.

RESULTS

A total of 1471 patients with AF were new users of a NOAC drug (228 apixaban, 645 dabigatran, 598 rivaroxaban) and 1348 were new users of warfarin. Mean age on a NOAC was 76 years (58% male), on warfarin 74 years (54% male). Only 9% (95% CI 7-10) failed to collect the first repeat prescription on a NOAC, 30% (27-32) discontinued within 12 months; corresponding proportions on warfarin were 14% (12-16) and 62% (60-65). In a regression model adjusted for age, gender, heart failure, hypertension and diabetes, warfarin-treated patients were 2.5 times more likely to discontinue over 12 months than those who were NOAC treated (hazard ratio =2.47 [95% CI 2.19-2.79]).

CONCLUSIONS

Persistence with NOAC drugs in patients with AF appears to be superior to warfarin. If continued long-term, this alone will be of clinical importance in the prevention of stroke and death.

Use of Direct-Acting Oral Anticoagulants in Nonagenarians: A Call for More Data

The prevalence and embolic risk of atrial fibrillation (AF) increase with age. Vitamin K antagonists (VKAs) or direct-acting oral anticoagulants (DOACs) reduce the risk of stroke or embolism. The aim of this review was to summarize the paucity of information regarding the safety and efficacy of DOACs in AF patients aged 90 years or older. The maximum age of included patients is not listed in any of the available DOAC investigating trials and registries, thus it is unclear if nonagenarians were included. Additionally, we could not find any subgroup analysis addressing this issue. There is an urgent need to collect more information on the safety and efficacy of oral anticoagulants in nonagenarians, especially regarding the role of DOACs, which are increasingly prescribed to this group of patients despite the lack of data. The best solution to this problem would be a prospective, randomized trial in this group of patients, however that would require a large investment of time, effort, and funds. In the meantime, we suggest subgroup analyses addressing the effects and safety of VKAs versus DOACs in nonagenarians, in case they have been included in previously completed or ongoing trials or registries. This could be feasible and would be desirable in view of the large amount of data already accumulated. Irrespective of age, anemia in patients receiving DOACs should be carefully investigated to rule out occult blood loss. With their known interaction profile and the possibility of monitoring these drugs, VKAs should be favored over DOACs in nonagenarians until more data are available regarding the safety of DOACs.

Minimizing bleeding risk in patients receiving direct oral anticoagulants for stroke prevention

Many primary care physicians are wary about using direct oral anticoagulants (DOACs) in patients with nonvalvular atrial fibrillation (AF). Factors such as comorbidities, concomitant medications, and alcohol misuse increase concerns over bleeding risk, especially in elderly and frail patients with AF. This article discusses strategies to minimize the risk of major bleeding events in patients with AF who may benefit from oral anticoagulant therapy for stroke prevention. The potential benefits of the DOACs compared with vitamin K antagonists, in terms of a lower risk of intracranial hemorrhage, are discussed, together with the identification of reversible risk factors for bleeding and correct dose selection of the DOACs based on a patient’s characteristics and concomitant medications. Current bleeding management strategies, including the new reversal agents for the DOACs and the prevention of bleeding during preoperative anticoagulation treatment, in addition to health care resource use associated with anticoagulation treatment and bleeding, are also discussed. Implementing a structured approach at an individual patient level will minimize the overall risk of bleeding and should increase physician confidence in using the DOACs for stroke prevention in their patients with nonvalvular AF.

Validity of peptic ulcer disease and upper gastrointestinal bleeding diagnoses in administrative databases: a systematic review protocol

INTRODUCTION

Administrative healthcare databases are useful to investigate the epidemiology, health outcomes, quality indicators and healthcare utilisation concerning peptic ulcers and gastrointestinal bleeding, but the databases need to be validated in order to be a reliable source for research. The aim of this protocol is to perform the first systematic review of studies reporting the validation of International Classification of Diseases, 9th Revision and 10th version (ICD-9 and ICD-10) codes for peptic ulcer and upper gastrointestinal bleeding diagnoses.

METHODS AND ANALYSIS

MEDLINE, EMBASE, Web of Science and the Cochrane Library databases will be searched, using appropriate search strategies. We will include validation studies that used administrative data to identify peptic ulcer disease and upper gastrointestinal bleeding diagnoses or studies that evaluated the validity of peptic ulcer and upper gastrointestinal bleeding codes in administrative data. The following inclusion criteria will be used: (a) the presence of a reference standard case definition for the diseases of interest; (b) the presence of at least one test measure (eg, sensitivity, etc) and (c) the use of an administrative database as a source of data. Pairs of reviewers will independently abstract data using standardised forms and will evaluate quality using the checklist of the Standards for Reporting of Diagnostic Accuracy (STARD) criteria. This systematic review protocol has been produced in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocol (PRISMA-P) 2015 statement.

ETHICS AND DISSEMINATION

Ethics approval is not required given that this is a protocol for a systematic review. We will submit results of this study to a peer-reviewed journal for publication. The results will serve as a guide for researchers validating administrative healthcare databases to determine appropriate case definitions for peptic ulcer disease and upper gastrointestinal bleeding, as well as to perform outcome research using administrative healthcare databases of these conditions.

TRIAL REGISTRATION NUMBER

CRD42015029216.

Impact on Drug Safety of Variation in Adherence: The Need for Routinely Reporting Measures of Dose Intensity in Medication Safety Studies Using Electronic Health Data

Randomized controlled trials always report the dose assessed and usually include a measure of adherence. By comparison, observational studies assessing medication safety often fail to report the dose used and rarely report any measure of adherence to therapy. This limits the ability to control for differences in doses used when undertaking meta-analyses. Non-adherence with therapy is common in the practice setting and varies across countries and settings. Inter-country differences in the registration of medicines may also result in different product strengths being available in different countries. These two factors combined means that observational studies undertaken for the same medicine in different settings may be assessing the same medicine but in circumstances where quite different dosages are used. Given that many adverse drug effects are dose dependent, differences in dosages used could be a factor explaining differences in risk estimates observed across studies. We argue that dose intensity, which can be defined as a product of the dose prescribed and adherence to the dose prescribed over the course of treatment, should be routinely reported in observational studies of medication safety. We illustrate the issue with the example of dabigatran. The randomized controlled trial evidence underpinning dabigatran’s marketing authorization resulted in uncertainty about the appropriate dose for efficacy versus safety. As a result, different dosages of dabigatran were registered in the USA and Europe. The USA registered the 150- and 75-mg dabigatran products, while the 150- and 110-mg dabigatran products were registered in Europe. Among five observational studies subsequently undertaken to resolve the safety question concerning dabigatran and risk of bleeding, only one stratified results by dose. None of the US studies stratified results by the 75-mg dabigatran dose, despite this dose not being assessed in the original trial. None of the five studies reported adherence measures, despite three separate observational studies finding between 25 and 40 % of patients were non-adherent to dabigatran. The STROBE and RECORD statements should consider adding the requirement for reporting measures of dose intensity and its component products to improve observational study reports.

How we treat bleeding associated with direct oral anticoagulants

Direct oral anticoagulants are at least as effective as vitamin K antagonists for the prevention and treatment of thromboembolism. Unfortunately, differently from vitamin K antagonists, they have the great drawback of lacking specific antidotes in the case of bleeding or emergency situations such as trauma, stroke requiring thrombolysis, and urgent surgery. The progressive development of antidotes for these new drugs, which, it is hoped, will become available in the near future, will allow better and safer management of the rapid reversal of their anticoagulant effect.

Major bleeding risk among non-valvular atrial fibrillation patients initiated on apixaban, dabigatran, rivaroxaban or warfarin: a "real-world" observational study in the United States

BACKGROUND

Limited data are available about the real-world safety of non-vitamin K antagonist oral anticoagulants (NOACs).

OBJECTIVES

To compare the major bleeding risk among newly anticoagulated non-valvular atrial fibrillation (NVAF) patients initiating apixaban, warfarin, dabigatran or rivaroxaban in the United States.

METHODS AND RESULTS

A retrospective cohort study was conducted to compare the major bleeding risk among newly anticoagulated NVAF patients initiating warfarin, apixaban, dabigatran or rivaroxaban. The study used the Truven MarketScan(®) Commercial & Medicare supplemental US database from 1 January 2013 through 31 December 2013. Major bleeding was defined as bleeding requiring hospitalisation. Cox model estimated hazard ratios (HRs) of major bleeding were adjusted for age, gender, baseline comorbidities and co-medications. Among 29 338 newly anticoagulated NVAF patients, 2402 (8.19%) were on apixaban; 4173 (14.22%) on dabigatran; 10 050 (34.26%) on rivaroxaban; and 12 713 (43.33%) on warfarin. After adjusting for baseline characteristics, initiation on warfarin [adjusted HR (aHR): 1.93, 95% confidence interval (CI): 1.12-3.33, P=.018] or rivaroxaban (aHR: 2.19, 95% CI: 1.26-3.79, P=.005) had significantly greater risk of major bleeding vs apixaban. Dabigatran initiation (aHR: 1.71, 95% CI: 0.94-3.10, P=.079) had a non-significant major bleeding risk vs apixaban. When compared with warfarin, apixaban (aHR: 0.52, 95% CI: 0.30-0.89, P=.018) had significantly lower major bleeding risk. Patients initiating rivaroxaban (aHR: 1.13, 95% CI: 0.91-1.41, P=.262) or dabigatran (aHR: 0.88, 95% CI: 0.64-1.21, P=.446) had a non-significant major bleeding risk vs warfarin.

CONCLUSION

Among newly anticoagulated NVAF patients in the real-world setting, initiation with rivaroxaban or warfarin was associated with a significantly greater risk of major bleeding compared with initiation on apixaban. When compared with warfarin, initiation with apixaban was associated with significantly lower risk of major bleeding. Additional observational studies are required to confirm these findings.

The association between non-vitamin K antagonist oral anticoagulants and gastrointestinal bleeding: a meta-analysis of observational studies

Particular concerns have been raised regarding the association between non-vitamin K antagonist oral anticoagulants (NOACs) and the risk of gastrointestinal bleeding (GIB); however, current findings are still inconclusive. We conducted a systematic review with a meta-analysis to examine the association between NOACs and GIB in real-life settings. We performed a systematic search of PubMed, EMBASE and CINAHL Plus up to September 2015. Observational studies that evaluated exposure to NOACs reporting GIB outcomes were included. The inverse variance method using the random-effects model was used to calculate the pooled estimates. Eight cohort studies were included in the primary meta-analysis, enrolling 1442 GIB cases among 106 626 dabigatran users (49 486 patient-years), and 184 GIB cases among 10 713 rivaroxaban users (4046 patient-years). The pooled incidence rates of GIB were 4.50 [95% confidence interval (CI) 3.17, 5.84] and 7.18 (95% CI 2.42, 12.0) per 100 patient-years among dabigatran and rivaroxaban users, respectively. The summary risk ratio (RR) was 1.21 (95% CI 1.05, 1.39) for dabigatran compared with warfarin, and 1.09 (95% CI 0.92, 1.30) for rivaroxaban. Subgroup analyses showed a dose-related effect of dabigatran, with a significantly higher risk of GIB for 150 mg b.i.d. (RR = 1.51, 95% CI 1.34, 1.70) but not for 75 mg b.i.d. or 110 mg b.i.d.. In addition, the use of proton pump inhibitors (PPIs)/histamine H2-receptor antagonists (H2RAs) influenced the association in dabigatran users, whereas this effect was modest among rivaroxaban users. In conclusion, our meta-analysis suggested a slightly higher risk of GIB with dabigatran use compared with warfarin, whereas no significant difference was found between rivaroxaban and warfarin for GIB risk.

The Effect of Anesthetic Type on Outcomes of Hip Fracture Surgery: A Nationwide Population-Based Study

Hip fractures are a global public health problem. During surgery following hip fractures, both general and regional anesthesia are used, but which type of anesthesia offers a better outcome remains controversial. There has been little research evaluating different anesthetic types on mortality and readmission rates for hip fracture surgery using nationwide population-based data.We used nationwide population-based data to examine the effect of anesthetic type on mortality and readmission rates for hip fracture surgery.Retrospective observational study.General acute care hospitals throughout Taiwan.A total of 17,189 patients hospitalized for hip fracture surgery in 2011.Generalized estimating equation models with propensity score weighting were performed after adjustment for patient, surgeon, and hospital characteristics to examine the associations of anesthesia type with 30-day all-cause mortality, 30-day all-cause readmission, and 30-day specific-cause readmission (including surgical site infection, sepsis, acute respiratory failure, acute stroke, acute myocardial infarction, acute renal failure, deep vein thrombosis, pneumonia, and urinary tract infection).Of 17,189 patients, 11,153 (64.9%) received regional anesthesia and 6036 (35.1%) received general anesthesia. Overall, the 30-day mortality rate was 1.7%, and the 30-day readmission rate was 12.3%. Regional anesthesia was not associated with decreased 30-day all-cause mortality (odds ratio [OR] 0.89, 95% confidence interval [CI] 0.67-1.18, P = 0.409), but associated with decreased 30-day all-cause readmission and surgical site infection readmission relative to general anesthesia (OR 0.83, 95% CI 0.75-0.93, P = 0.001 and OR 0.69, 95% CI 0.49-0.97, P = 0.031).Regional anesthesia is not associated with 30-day mortality, but is associated with lower 30-day all-cause and surgical site infection readmission compared with general anesthesia for hip fracture surgery.

Gastrointestinal Bleeding in Patients With Atrial Fibrillation Treated With Rivaroxaban or Warfarin: ROCKET AF Trial

BACKGROUND

Gastrointestinal (GI) bleeding is a common complication of oral anticoagulation.

OBJECTIVES

This study evaluated GI bleeding in patients who received at least 1 dose of the study drug in the on-treatment arm of the ROCKET AF (Rivaroxaban Once-daily Oral Direct Factor Xa Inhibition Compared with Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation) trial.

METHODS

The primary outcome was adjudicated GI bleeding reported from first to last drug dose + 2 days. Multivariable modeling was performed with pre-specified candidate predictors.

RESULTS

Of 14,236 patients, 684 experienced GI bleeding during follow-up. These patients were older (median age 75 years vs. 73 years) and less often female. GI bleeding events occurred in the upper GI tract (48%), lower GI tract (23%), and rectum (29%) without differences between treatment arms. There was a significantly higher rate of major or nonmajor clinical GI bleeding in rivaroxaban- versus warfarin-treated patients (3.61 events/100 patient-years vs. 2.60 events/100 patient-years; hazard ratio: 1.42; 95% confidence interval: 1.22 to 1.66). Severe GI bleeding rates were similar between treatment arms (0.47 events/100 patient-years vs. 0.41 events/100 patient-years; p = 0.39; 0.01 events/100 patient-years vs. 0.04 events/100 patient-years; p = 0.15, respectively), and fatal GI bleeding events were rare (0.01 events/100 patient-years vs. 0.04 events/100 patient-years; 1 fatal events vs. 5 fatal events total). Independent clinical factors most strongly associated with GI bleeding were baseline anemia, history of GI bleeding, and long-term aspirin use.

CONCLUSIONS

In the ROCKET AF trial, rivaroxaban increased GI bleeding compared with warfarin. The absolute fatality rate from GI bleeding was low and similar in both treatment arms. Our results further illustrate the need for minimizing modifiable risk factors for GI bleeding in patients on oral anticoagulation.

Effect of Adherence to Oral Anticoagulants on Risk of Stroke and Major Bleeding Among Patients With Atrial Fibrillation

BACKGROUND

In comparison to warfarin, non-vitamin K antagonist oral anticoagulants (NOACs) have the advantages of ease of dosing, fewer drug interactions, and lack of need for ongoing monitoring. We sought to evaluate whether these advantages translate to improved adherence and whether adherence is associated with improved outcomes in patients with atrial fibrillation.

METHODS AND RESULTS

We performed a retrospective cohort analysis by using a large US commercial insurance database to identify 64 661 patients with atrial fibrillation who initiated warfarin, dabigatran, rivaroxaban, or apixaban treatment between November 1, 2010, and December 31, 2014. During a median of 1.1 y of follow-up, 47.5% of NOAC patients had a proportion of days covered of ≥80%, compared with 40.2% in warfarin patients (P<0.001). Patients with CHA2DS2-VASc (risk based on the presence of congestive heart failure, hypertension age 65-74 y, age ≥75 y, diabetes mellitus, prior stroke or transient ischemic attack, vascular disease, sex category) score ≥4 were at increased risk of stroke when they were not taking anticoagulation ≥1 month versus <1 week (1-3 months: hazard ratio [HR] 1.96, 3-6 months: HR 2.64, ≥6 months: HR 3.66; all P<0.001). Patients with CHA2DS2-VASc score 2 or 3 were at increased risk of stroke when they were not taking anticoagulation ≥6 months (HR 2.73, P<0.001). In these patients with CHA2DS2-VASc score ≥2, nonadherence was not associated with intracranial hemorrhage. Among patients with CHA2DS2-VASc score 0 or 1, time not taking anticoagulation was not associated with stroke, but not taking anticoagulation ≥3 months was associated with a significant reduction of bleeding.

CONCLUSIONS

Adherence to anticoagulation is poor in practice and may be modestly improved with NOACs. Adherence to therapy appears to be most important in patients with CHA2DS2-VASc score ≥2, whereas the benefits of anticoagulation may not outweigh the harms in patients with CHA2DS2-VASc score 0 or 1.

Risk of Gastrointestinal Bleeding with Rivaroxaban: A Comparative Study with Warfarin

Introduction. The risk of gastrointestinal (GI) bleeding with rivaroxaban has not been studied extensively. The aim of our study was to assess this risk in comparison to warfarin. Methods. We examined the medical records for patients who were started on rivaroxaban or warfarin from April 2011 to April 2013. Results. We identified 300 patients (147 on rivaroxaban versus 153 on warfarin). GI bleeding occurred in 4.8% patients with rivaroxaban when compared to 9.8% patients in warfarin group (p = 0.094). GI bleeding occurred in 8% with therapeutic doses of rivaroxaban (>10 mg/d) compared to 9.8% with warfarin (p = 0.65). Multivariate analysis showed that patients who were on rivaroxaban for ≤40 days had a higher incidence of GI bleeding than those who were on it for >40 days (OR = 2.8, p = 0.023). Concomitant use of dual antiplatelet agents was associated with increased risk of GI bleeding in the rivaroxaban group (OR = 7.4, p = 0.0378). Prior GI bleeding was also a risk factor for GI bleeding in rivaroxaban group (OR = 15.5). Conclusion. The incidence of GI bleeding was similar between rivaroxaban and warfarin. The risk factors for GI bleeding with rivaroxaban were the first 40 days of taking the drug, concomitant dual antiplatelet agents, and prior GI bleeding.