Comparison of treatment effect estimates of non-vitamin K antagonist oral anticoagulants versus warfarin between observational studies using propensity score methods and randomized controlled trials

Impact of diagnostic coding schemas on major bleeding risk assessment for oral anticoagulants in patients with atrial fibrillation using administrative claims data

BACKGROUND

Reliable diagnostic coding schemas are essential for accurately assessing bleeding risks in patients on oral anticoagulants, particularly in observational studies.

OBJECTIVES

This study evaluated how different published diagnostic coding schemas impact the assessment of major bleeding risks associated with direct oral anticoagulants (DOACs) and warfarin.

METHODS

This retrospective cohort study included patients with atrial fibrillation who initiated DOACs or warfarin between 2012 and 2019 using Taiwan's national claims database. Major bleeding events, including gastrointestinal bleeding, intracranial hemorrhage (ICH), and other major bleeding events, were identified using coding schemas from Cunningham et al., the Mini-Sentinel protocol, and Yao et al. Propensity score matching was performed to ensure covariate balance. Incidence rates and hazard ratios (HRs) were estimated to evaluate the bleeding risks.

RESULTS

After matching, each cohort comprised 20 704 patients. The number of reported major bleeding events was influenced by the strictness of the coding schema, with Cunningham yielding the most events, followed by the Mini-Sentinel and Yao schemas. DOACs were associated with a consistently lower risk of composite major bleeding (HR range across different coding schemas, 0.73-0.76; all P < .05) and ICH (HR range, 0.43-0.63; all P < .05) but not gastrointestinal bleeding (HR range, 0.87-0.90; all P > .05), regardless of the coding schema applied. Restricting ICH definitions to primary diagnosis or spontaneous cases revealed a more pronounced reduction in ICH risk associated with DOACs.

CONCLUSION

While the choice of coding schemas has a negligible impact on overall bleeding risk comparisons between DOACs and warfarin, it significantly affects ICH risk assessment. This underscores the importance of careful coding schema selection in observational studies evaluating major bleeding risks.

Treatment Effects in Randomized and Nonrandomized Studies of Pharmacological Interventions: A Meta-Analysis

Importance

Randomized clinical trials (RCTs) are widely regarded as the methodological benchmark for assessing clinical efficacy and safety of health interventions. There is growing interest in using nonrandomized studies to assess efficacy and safety of new drugs.

Objective

To determine how treatment effects for the same drug compare when evaluated in nonrandomized vs randomized studies.

Data Sources

Meta-analyses published between 2009 and 2018 were identified in MEDLINE via PubMed and the Cochrane Database of Systematic Reviews. Data analysis was conducted from October 2019 to July 2024.

Study Selection

Meta-analyses of pharmacological interventions were eligible for inclusion if both randomized and nonrandomized studies contributed to a single meta-analytic estimate.

Data Extraction and Synthesis

For this meta-analysis using a meta-epidemiological framework, separate summary effect size estimates were calculated for nonrandomized and randomized studies within each meta-analysis using a random-effects model and then these estimates were compared. The reporting of this study followed the Guidelines for Reporting Meta-Epidemiological Methodology Research and relevant portions of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guideline.

Main Outcome and Measures

The primary outcome was discrepancies in treatment effects obtained from nonrandomized and randomized studies, as measured by the proportion of meta-analyses where the 2 study types disagreed about the direction or magnitude of effect, disagreed beyond chance about the effect size estimate, and the summary ratio of odds ratios (ROR) obtained from nonrandomized vs randomized studies combined across all meta-analyses.

Results

A total of 346 meta-analyses with 2746 studies were included. Statistical conclusions about drug benefits and harms were different for 130 of 346 meta-analyses (37.6%) when focusing solely on either nonrandomized or randomized studies. Disagreements were beyond chance for 54 meta-analyses (15.6%). Across all meta-analyses, there was no strong evidence of consistent differences in treatment effects obtained from nonrandomized vs randomized studies (summary ROR, 0.95; 95% credible interval [CrI], 0.89-1.02). Compared with experimental nonrandomized studies, randomized studies produced on average a 19% smaller treatment effect (ROR, 0.81; 95% CrI, 0.68-0.97). There was increased heterogeneity in effect size estimates obtained from nonrandomized compared with randomized studies.

Conclusions and Relevance

In this meta-analysis of treatment effects of pharmacological interventions obtained from randomized and nonrandomized studies, there was no overall difference in effect size estimates between study types on average, but nonrandomized studies both overestimated and underestimated treatment effects observed in randomized studies and introduced additional uncertainty. These findings suggest that relying on nonrandomized studies as substitutes for RCTs may introduce additional uncertainty about the therapeutic effects of new drugs.

Association Between Remnant Cholesterol and Risk of Incident Atrial Fibrillation: Population-Based Evidence From a Large-Scale Prospective Cohort Study

BACKGROUND

Evidence for the relationship between remnant cholesterol (RC) and incident atrial fibrillation (AF) risk remains sparse and limited.

METHODS AND RESULTS

Participants were enrolled between 2006 and 2010 and followed up to 2021. The multivariable Cox proportional hazards model was used to examine the relationship between RC quartiles and risk of incident AF. Subgroup analyses and sensitivity analyses were performed to explore the potential modification of the association and the robustness of the main findings. A total of 422 316 participants (mean age, 56 years; 54% women) were included for analyses. During a median follow-up of 11.9 years (first quartile-third quartile, 11.6-13.2 years), there were 24 774 AF events documented with an incidence of 4.92 events per 1000 person-years (95% CI, 4.86-4.98). Participants in higher RC quartiles had a lower risk of incident AF than those in the lowest quartile (first quartile): hazard ratio (HR)=0.96 (95% CI, 0.91-1.00) for second quartile; HR=0.92 (95% CI, 0.88-0.96) for third quartile; and HR=0.85 (95% CI, 0.81-0.89) for fourth quartile (P for trend <0.001). The association between RC quartiles and risk of incident AF was stronger in participants aged ≥65 years, in men, and in participants without history of diabetes when compared with control groups (P<0.001 for interaction).

CONCLUSIONS

On the basis of data from this large-scale prospective cohort study, elevated RC was associated with a lower risk of incident AF.

Healthcare outcomes assessed with observational study designs compared with those assessed in randomized trials: a meta-epidemiological study

BACKGROUND

Researchers and decision-makers often use evidence from randomised controlled trials (RCTs) to determine the efficacy or effectiveness of a treatment or intervention. Studies with observational designs are often used to measure the effectiveness of an intervention in 'real world' scenarios. Numerous study designs and their modifications (including both randomised and observational designs) are used for comparative effectiveness research in an attempt to give an unbiased estimate of whether one treatment is more effective or safer than another for a particular population. An up-to-date systematic analysis is needed to identify differences in effect estimates from RCTs and observational studies. This updated review summarises the results of methodological reviews that compared the effect estimates of observational studies with RCTs from evidence syntheses that addressed the same health research question.

OBJECTIVES

To assess and compare synthesised effect estimates by study type, contrasting RCTs with observational studies. To explore factors that might explain differences in synthesised effect estimates from RCTs versus observational studies (e.g. heterogeneity, type of observational study design, type of intervention, and use of propensity score adjustment). To identify gaps in the existing research comparing effect estimates across different study types.

SEARCH METHODS

We searched MEDLINE, the Cochrane Database of Systematic Reviews, Web of Science databases, and Epistemonikos to May 2022. We checked references, conducted citation searches, and contacted review authors to identify additional reviews.

SELECTION CRITERIA

We included systematic methodological reviews that compared quantitative effect estimates measuring the efficacy or effectiveness of interventions tested in RCTs versus in observational studies. The included reviews compared RCTs to observational studies (including retrospective and prospective cohort, case-control and cross-sectional designs). Reviews were not eligible if they compared RCTs with studies that had used some form of concurrent allocation.

DATA COLLECTION AND ANALYSIS

Using results from observational studies as the reference group, we examined the relative summary effect estimates (risk ratios (RRs), odds ratios (ORs), hazard ratios (HRs), mean differences (MDs), and standardised mean differences (SMDs)) to evaluate whether there was a relatively larger or smaller effect in the ratio of odds ratios (ROR) or ratio of risk ratios (RRR), ratio of hazard ratios (RHR), and difference in (standardised) mean differences (D(S)MD). If an included review did not provide an estimate comparing results from RCTs with observational studies, we generated one by pooling the estimates for observational studies and RCTs, respectively. Across all reviews, we synthesised these ratios to produce a pooled ratio of ratios comparing effect estimates from RCTs with those from observational studies. In overviews of reviews, we estimated the ROR or RRR for each overview using observational studies as the reference category. We appraised the risk of bias in the included reviews (using nine criteria in total). To receive an overall low risk of bias rating, an included review needed: explicit criteria for study selection, a complete sample of studies, and to have controlled for study methodological differences and study heterogeneity. We assessed reviews/overviews not meeting these four criteria as having an overall high risk of bias. We assessed the certainty of the evidence, consisting of multiple evidence syntheses, with the GRADE approach.

MAIN RESULTS

We included 39 systematic reviews and eight overviews of reviews, for a total of 47. Thirty-four of these contributed data to our primary analysis. Based on the available data, we found that the reviews/overviews included 2869 RCTs involving 3,882,115 participants, and 3924 observational studies with 19,499,970 participants. We rated 11 reviews/overviews as having an overall low risk of bias, and 36 as having an unclear or high risk of bias. Our main concerns with the included reviews/overviews were that some did not assess the quality of their included studies, and some failed to account appropriately for differences between study designs - for example, they conducted aggregate analyses of all observational studies rather than separate analyses of cohort and case-control studies. When pooling RORs and RRRs, the ratio of ratios indicated no difference or a very small difference between the effect estimates from RCTs versus from observational studies (ratio of ratios 1.08, 95% confidence interval (CI) 1.01 to 1.15). We rated the certainty of the evidence as low. Twenty-three of 34 reviews reported effect estimates of RCTs and observational studies that were on average in agreement. In a number of subgroup analyses, small differences in the effect estimates were detected: - pharmaceutical interventions only (ratio of ratios 1.12, 95% CI 1.04 to 1.21); - RCTs and observational studies with substantial or high heterogeneity; that is, I2 ≥ 50% (ratio of ratios 1.11, 95% CI 1.04 to 1.18); - no use (ratio of ratios 1.07, 95% CI 1.03 to 1.11) or unclear use (ratio of ratios 1.13, 95% CI 1.03 to 1.25) of propensity score adjustment in observational studies; and - observational studies without further specification of the study design (ratio of ratios 1.06, 95% CI 0.96 to 1.18). We detected no clear difference in other subgroup analyses.

AUTHORS' CONCLUSIONS

We found no difference or a very small difference between effect estimates from RCTs and observational studies. These findings are largely consistent with findings from recently published research. Factors other than study design need to be considered when exploring reasons for a lack of agreement between results of RCTs and observational studies, such as differences in the population, intervention, comparator, and outcomes investigated in the respective studies. Our results underscore that it is important for review authors to consider not only study design, but the level of heterogeneity in meta-analyses of RCTs or observational studies. A better understanding is needed of how these factors might yield estimates reflective of true effectiveness.

Design, implementation, and inferential issues associated with clinical trials that rely on data in electronic medical records: a narrative review

Real world evidence is now accepted by authorities charged with assessing the benefits and harms of new therapies. Clinical trials based on real world evidence are much less expensive than randomized clinical trials that do not rely on "real world evidence" such as contained in electronic health records (EHR). Consequently, we can expect an increase in the number of reports of these types of trials, which we identify here as 'EHR-sourced trials.' 'In this selected literature review, we discuss the various designs and the ethical issues they raise. EHR-sourced trials have the potential to improve/increase common data elements and other aspects of the EHR and related systems. Caution is advised, however, in drawing causal inferences about the relationships among EHR variables. Nevertheless, we anticipate that EHR-CTs will play a central role in answering research and regulatory questions.

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

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

Comparative Effectiveness and Safety Between Apixaban, Dabigatran, Edoxaban, and Rivaroxaban Among Patients With Atrial Fibrillation : A Multinational Population-Based Cohort Study

BACKGROUND

Current guidelines recommend using direct oral anticoagulants (DOACs) over warfarin in patients with atrial fibrillation (AF), but head-to-head trial data do not exist to guide the choice of DOAC.

OBJECTIVE

To do a large-scale comparison between all DOACs (apixaban, dabigatran, edoxaban, and rivaroxaban) in routine clinical practice.

DESIGN

Multinational population-based cohort study.

SETTING

Five standardized electronic health care databases, which covered 221 million people in France, Germany, the United Kingdom, and the United States.

PARTICIPANTS

Patients who were newly diagnosed with AF from 2010 through 2019 and received a new DOAC prescription.

MEASUREMENTS

Database-specific hazard ratios (HRs) of ischemic stroke or systemic embolism, intracranial hemorrhage (ICH), gastrointestinal bleeding (GIB), and all-cause mortality between DOACs were estimated using a Cox regression model stratified by propensity score and pooled using a random-effects model.

RESULTS

A total of 527 226 new DOAC users met the inclusion criteria (apixaban, n = 281 320; dabigatran, n = 61 008; edoxaban, n = 12 722; and rivaroxaban, n = 172 176). Apixaban use was associated with lower risk for GIB than use of dabigatran (HR, 0.81 [95% CI, 0.70 to 0.94]), edoxaban (HR, 0.77 [CI, 0.66 to 0.91]), or rivaroxaban (HR, 0.72 [CI, 0.66 to 0.79]). No substantial differences were observed for other outcomes or DOAC-DOAC comparisons. The results were consistent for patients aged 80 years or older. Consistent associations between lower GIB risk and apixaban versus rivaroxaban were observed among patients receiving the standard dose (HR, 0.72 [CI, 0.64 to 0.82]), those receiving a reduced dose (HR, 0.68 [CI, 0.61 to 0.77]), and those with chronic kidney disease (HR, 0.68 [CI, 0.59 to 0.77]).

LIMITATION

Residual confounding is possible.

CONCLUSION

Among patients with AF, apixaban use was associated with lower risk for GIB and similar rates of ischemic stroke or systemic embolism, ICH, and all-cause mortality compared with dabigatran, edoxaban, and rivaroxaban. This finding was consistent for patients aged 80 years or older and those with chronic kidney disease, who are often underrepresented in clinical trials.

PRIMARY FUNDING SOURCE

None.

Real-world evidence comparing oral anticoagulants in non-valvular atrial fibrillation: a systematic review and network meta-analysis

Aim: To compare real-world effectiveness/safety of non-vitamin K antagonist oral anticoagulants and vitamin K antagonists among patients with non-valvular atrial fibrillation. Materials & methods: A systematic review of electronic databases yielded 7661 citations published from January 2013 to January 2020. Fifty-five studies were included in Bayesian network meta-analyses of hazard ratios. Results & conclusion: In comparison with vitamin K antagonists, apixaban, dabigatran and rivaroxaban were associated with a reduced risk of stroke or systemic embolism, ischemic stroke, intracranial hemorrhage and all-cause mortality. Apixaban, dabigatran and edoxaban, but not rivaroxaban, were associated with a reduced risk of major bleeding. This study confirmed the effectiveness and safety of non-vitamin K antagonist oral anticoagulants for the treatment of non-valvular atrial fibrillation in real-world settings, consistent with clinical trial evidence.

Predicting major bleeding among hospitalized patients using oral anticoagulants for atrial fibrillation after discharge

Aim

Real-world predictors of major bleeding (MB) have been well-studied among warfarin users, but not among all direct oral anticoagulant (DOAC) users diagnosed with atrial fibrillation (AF). Thus, our goal was to build a predictive model of MB for new users of all oral anticoagulants (OAC) with AF.

Methods

We identified patients hospitalized for any cause and discharged alive in the community from 2011 to 2017 with a primary or secondary diagnosis of AF in Quebec’s RAMQ and Med-Echo administrative databases. Cohort entry occurred at the first OAC claim. Patients were categorized according to OAC type. Outcomes were incident MB, gastrointestinal bleeding (GIB), non-GI extracranial bleeding (NGIB) and intracranial bleeding within 1 year of follow-up. Covariates included age, sex, co-morbidities (within 3 years before cohort entry) and medication use (within 2 weeks before cohort entry). We used logistic-LASSO and adaptive logistic-LASSO regressions to identify MB predictors among OAC users. Discrimination and calibration were assessed for each model and a global model was selected. Subgroup analyses were performed for MB subtypes and OAC types.

Results

Our cohort consisted of 14,741 warfarin, 3,722 dabigatran, 6,722 rivaroxaban and 11,196 apixaban users aged 70–86 years old. The important MB predictors were age, prior MB and liver disease with ORs ranging from 1.37–1.64. The final model had a c-statistic of 0.63 (95% CI 0.60–0.65) with adequate calibration. The GIB and NGIB models had similar c-statistics of 0.65 (95% CI 0.63–0.66) and 0.67 (95% CI 0.64–0.70), respectively.

Conclusions

MB and MB subtype predictors were similar among DOAC and warfarin users. The predictors selected by our models and their discriminative potential are concordant with published data. Thus, these models can be useful tools for future pharmacoepidemiologic studies involving older oral anticoagulant users with AF.

Compared to randomized studies, observational studies may overestimate the effectiveness of DOACs: a metaepidemiological approach

BACKGROUND AND OBJECTIVES

Randomized controlled trials (RCTs) are criticized for including patients who are overselected. Health authorities consequently encourage "real-world" postmarketing cohort studies. Our objective was to determine the differences between RCTs and observational studies as regards their populations and efficacy/safety results.

METHODS

A systematic review was conducted to identify RCTs and observational studies including patients with venous thromboembolism receiving direct oral anticoagulants or conventional treatment. Ratios of hazard ratio (RHR) comparing epidemiological studies (prospective and retrospective cohort studies and studies using living databases) with RCTs were computed.

RESULTS

Six RCTs (27,121 patients) and twenty observational studies (248,971 patients) were identified and analyzed. Prospective cohort studies seemed to recruit patients who were no less selected than those of RCTs whereas other types of observational studies may reflect the population treated in real life. Among observational studies, prospective cohort studies yielded the most favorable estimates of treatment effect compared with RCTs. These studies were associated with a nonsignificant 33% increase in efficacy estimate (RHR 0.67, [95% CI, 0.39-1.18]) but no effect on safety estimate. Studies using living databases were associated with nonsignificant trends toward a greater effect on efficacy (RHR 0.82, [0.66-1.01]) and a smaller effect on safety (RHR 1.33, [0.96-1.84]).

DISCUSSION

Overall, in this clinical setting, an exaggeration of the treatment efficacy estimate was seen with observational studies compared with RCTs.

CONCLUSIONS

As the presence of residual confounding cannot be excluded, these results should be interpreted cautiously.

Direct oral anticoagulants versus vitamin K antagonists in real-world patients with nonvalvular atrial fibrillation. The FANTASIIA study

INTRODUCTION AND OBJECTIVES

To compare the long-term results of direct oral anticoagulants (DOAC) vs vitamin K antagonists (VKA) in real-world-patients with nonvalvular atrial fibrillation (NVAF) in a nationwide, prospective study.

METHODS

The FANTASIIA registry prospectively included outpatients with AF anticoagulated with DOAC or VKA (per protocol, proportion of VKA and DOAC 4:1), consecutively recruited from June 2013 to October 2014 in Spain. The incidence of major events was analyzed and compared according to the anticoagulant treatment received.

RESULTS

A total of 2178 patients were included in the study (mean age 73.8±9.4 years), and 43.8% were women. Of these, 533 (24.5%) received DOAC and 1645 (75.5%) VKA. After a median follow up of 32.4 months, patients receiving DOAC vs those receiving VKA had lower rates of stroke-0.40 (95%CI, 0.17-0.97) vs 1.07 (95%CI,0.79-1.46) patients/y, P=.032-, severe bleedings-2.13 (95%CI, 1.45-3.13) vs 3.28 (95%CI, 2.75-3.93) patients/y; P = .044-, cardiovascular death-1.20 (95%CI, 0.72-1.99) vs 2.45 (95%CI, 2.00-3.00) patients/y; P = .009-, and all-cause death-3.77 (95%CI, 2.83-5.01) vs 5.54 (95%CI, 4.83-6.34) patients/y; P = .016-. In a modified Cox regression model by the Andersen-Gill method for multiple events, hazard ratios for patients receiving DOAC were: 0.42 (0.16-1.07) for stroke; 0.47 (0.20-1.16) for total embolisms; 0.76 (0.50-1.15) for severe bleedings; 0.67 (0.39-1.18) for cardiovascular death; 0.86 (0.62-1.19) for all-cause death, and 0.82 (0.64-1.05) for the combined event consisting of stroke, embolism, severe bleeding, and all-cause death.

CONCLUSIONS

Compared with VKA, DOAC is associated with a trend to a lower incidence of all major events, including death, in patients with NVAF in Spain.

Comparative effectiveness and safety of low-strength and high-strength direct oral anticoagulants compared with warfarin: a sequential cohort study

OBJECTIVES

The aim of this study was to compare effectiveness and safety of low-strength and high-strength direct oral anticoagulants (DOACs) with warfarin in the Australian Veteran population.

DESIGN

Sequential cohort study using inverse probability of treatment weighting (IPTW) and propensity score matching. Initiators of high-strength (apixaban 5 mg, dabigatran 150 mg, rivaroxaban 20 mg) and low-strength DOACS (apixaban 2.5 mg, dabigatran 110 mg, rivaroxaban 15 mg) were compared with warfarin initiators.

SETTING

Australian Government Department of Veterans' Affairs claims database.

PARTICIPANTS

4836 patients who initiated oral anticoagulants (45.8%, 26.0% and 28.2% on low-strength, high-strength DOACs and warfarin, respectively) between August 2013 and March 2015. Mean age was 85, 75 and 83 years for low-strength, high-strength DOACs and warfarin initiators, respectively.

MAIN OUTCOME MEASURES

One-year risk of hospitalisation for ischaemic stroke, any bleeding event or haemorrhagic stroke. Secondary outcomes were 1-year risk of hospitalisation for myocardial infarction and death.

RESULTS

Using the IPTW method, no difference in risk of ischaemic stroke or bleeding was found with low-strength DOACs compared with warfarin. As a class, no increased risk of myocardial infarction was found for low-strength DOACs, however, risk was elevated for apixaban (HR 2.25, 95% CI 1.23 to 4.13). For high-strength DOACs, no difference was found for ischaemic stroke compared with warfarin, however, there was a significant reduction in risk of bleeding events (HR 0.63, 95% CI 0.44 to 0.89) and death (HR 0.40, 95% CI 0.28 to 0.58). Propensity score matching showed no difference in risk of ischaemic stroke or bleeding.

CONCLUSION

We found that in the practice setting both DOAC formulations were similar to warfarin with regard to effectiveness and had no increased risk of bleeding.

Direct comparative effectiveness and safety between non-vitamin K antagonist oral anticoagulants for stroke prevention in nonvalvular atrial fibrillation: a systematic review and meta-analysis of observational studies

The non-vitamin K antagonist oral anticoagulants (NOACs) have been increasingly prescribed in clinical practice for stroke prevention in patients with nonvalvular atrial fibrillation (AF). Direct comparisons between NOACs in trials are lacking, leaving an important clinical decision-making gap. We aimed to perform a systematic review and meta-analysis to summarize the evidence of observational studies for direct comparative effectiveness and safety amongst NOACs in patients with AF. Conference proceedings and electronic databases including MEDLINE, CINAHL, EMBASE and PUBMED were systematically searched. We included observational studies directly comparing individual NOACs in patients with nonvalvular AF who were aged ≥ 18 years for stroke prevention. Primary outcome included effectiveness outcome (stroke or systemic embolism) and safety outcome (major bleeding). Data were extracted in duplicated by two reviewers independently. A random-effects meta-analysis was conducted to synthesize the data from included observational studies. We used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) to rate the overall quality of evidence for each outcome. Fifteen studies were included for qualitative synthesis, twelve studies for meta-analyses. It was found that rivaroxaban and dabigatran were similar with regard to risk of stroke or systemic embolism (Hazard ratio [HR] = 1.00, 95% CI 0.91-1.10; evidence quality: low), but rivaroxaban was associated with higher risk of major bleeding (HR = 1.39, 95% CI 1.28-1.50; evidence quality: moderate). Compared with apixaban, a significantly higher risk of major bleeding was observed with rivaroxaban (HR = 1.71, 95% CI 1.51-1.94; evidence quality: low). Apixaban was associated with lower risk of major bleeding, in comparison with dabigatran (HR = 0.80, 95% CI 0.68-0.95; evidence quality: low). No differences in risk of stroke or systemic embolism was observed between rivaroxaban versus apixaban, and apixaban versus dabigatran. In this study, apixaban was found to have the most favorable safety profile amongst the three NOACs. No significant difference was observed in risk of stroke or systemic embolism between the NOACs. Such findings may provide some decision-making support for physicians regarding their choices amongst NOACs in patients with AF.Registration PROSPERO (identifier: CRD42016052908).

Association of Whole-Body Computed Tomography With Mortality Risk in Children With Blunt Trauma

IMPORTANCE

Although several studies have demonstrated an improvement in mortality for injured adults who receive whole-body computed tomography (WBCT), it is unclear whether children experience the same benefit.

OBJECTIVE

To determine whether emergent WBCT is associated with lower mortality among children with blunt trauma compared with a selective CT approach.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective, multicenter cohort study was conducted from January 1, 2010, to December 31, 2014, using data from the National Trauma Data Bank on children aged 6 months to 14 years with blunt trauma who received an emergent CT scan in the first 2 hours after emergency department arrival. Data analysis was conducted from February 2 to December 29, 2017.

EXPOSURES

Patients were classified as having WBCT if they received CT head, CT chest, and CT abdomen/pelvis scans in the first 2 hours and as having a selective CT if they did not receive all 3 scans.

MAIN OUTCOMES AND MEASURES

The primary outcome was in-hospital mortality in the 7 days after ED arrival. To adjust for potential confounding, propensity score weighting was used. Subgroup analyses were performed for those with the highest mortality risk (ie, occupants and pedestrians involved in motor vehicle crashes, children with a Glasgow Coma Scale score lower than 9, children with hypotension, and those admitted to the intensive care unit).

RESULTS

Of the 42 912 children included in the study (median age [interquartile range], 9 [5-12] years; 27 861 [64.9%] boys), 8757 (20.4%) received a WBCT. Overall, 405 (0.9%) children died within 7 days. After adjusting for the propensity score, children who received WBCT had no significant difference in mortality compared with those who received selective CT (absolute risk difference, -0.2%; 95% CI, -0.6% to 0.1%). All subgroup analyses similarly showed no significant association between WBCT and mortality.

CONCLUSIONS AND RELEVANCE

Among children with blunt trauma, WBCT, compared with a selective CT approach, was not associated with lower mortality. These findings do not support the routine use of WBCT for children with blunt trauma.

New developments in anticoagulants: Past, present and future

Thrombosis is a leading cause of death and disability worldwide, and anticoagulants are the mainstay of its prevention and treatment. Starting with unfractionated heparin (UFH) and vitamin K antagonists (VKAs) such as warfarin, the choices of anticoagulants have exploded in the past 20 years. With over 90% subcutaneous bioavailability, no need for coagulation monitoring and dose adjustment, and a lower risk of heparin-induced thrombocytopenia, low-molecular-weight heparin and fondaparinux have replaced UFH for prevention and initial treatment of venous thromboembolism and for secondary prevention in cancer patients. In patients undergoing percutaneous interventions, bivalirudin is often used instead of UFH. Oral anticoagulation therapy has advanced with the introduction of the non-vitamin K antagonist oral anticoagulants (NOACs), which include dabigatran, rivaroxaban, apixaban and edoxaban. With efficacy at least equal to that of VKAs but with greater safety and convenience, the NOACs are now replacing VKAs for many indications. This paper a) highlights these advances, b) outlines how specific reversal agents for the NOACs will enhance their safety, c) reviews some of the ongoing trials with the NOACs, and d) describes the inhibitors of factor XII and XI that are under investigation as anticoagulants.

The Rotterdam Study: 2018 update on objectives, design and main results

The Rotterdam Study is a prospective cohort study ongoing since 1990 in the city of Rotterdam in The Netherlands. The study targets cardiovascular, endocrine, hepatic, neurological, ophthalmic, psychiatric, dermatological, otolaryngological, locomotor, and respiratory diseases. As of 2008, 14,926 subjects aged 45 years or over comprise the Rotterdam Study cohort. Since 2016, the cohort is being expanded by persons aged 40 years and over. The findings of the Rotterdam Study have been presented in over 1500 research articles and reports (see www.erasmus-epidemiology.nl/rotterdamstudy ). This article gives the rationale of the study and its design. It also presents a summary of the major findings and an update of the objectives and methods.

Emerging therapeutic uses of direct-acting oral anticoagulants: An evidence-based perspective

Direct-acting oral anticoagulants (DOACs) were claimed to cause a potential paradigm shift in the therapeutic scenario of patients requiring short- and long-term anticoagulation, by virtue of their pharmacological properties, perceived as innovative. The evidence gathered so far (from pre-approval pivotal trials to real-world post-marketing observational data) consistently confirmed that DOACs are overall comparable to vitamin-K antagonists (VKAs) in terms of safety, efficacy and effectiveness and unequivocally documented a consistent and clinically relevant reduced risk of intracranial bleeding in the settings of non-valvular atrial fibrillation (NVAF) and venous thromboembolism (VTE). Interestingly, two parallel paths can be identified in the current research scenario: A) in the aforementioned consolidated therapeutic indications, an innovative approach is directed towards tailored treatment strategies, to identify patients most likely to benefit from one of the different anticoagulant drugs, in particular subpopulations at increased risk of adverse events (e.g., bleeding); B) in unconventional settings, DOACs are gaining interest for potential use in emerging diseases characterized by arterial and venous thromboembolic risk. In these scenarios, the risk-benefit profile of DOACs, as compared to VKAs or heparins, is less defined. The aim of this review is to critically assess the body of evidence underlying emerging therapeutic uses of DOACs (e.g., heparin-induced thrombocytopenia, anti-phospholipid antibody syndrome), including evolving issues in special populations (e.g., patients with VTE and cancer or cirrhosis). This will be achieved by analyzing the strength (i.e., systematic reviews, randomized clinical trials, observational studies, case report/series) and consistency (i.e., concordance) of both published and unpublished evidence registered in major public repositories.

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.