Association is not causation: treatment effects cannot be estimated from observational data in heart failure

Lymphocyte-to-C-Reactive Protein (LCR) Ratio Is Not Accurate to Predict Severity and Mortality in Patients with COVID-19 Admitted to the ED

Health care systems worldwide have been battling the ongoing COVID-19 pandemic. Since the beginning of the COVID-19 pandemic, Lymphocytes and CRP have been reported as markers of interest. We chose to investigate the prognostic value of the LCR ratio as a marker of severity and mortality in COVID-19 infection. Between 1 March and 30 April 2020, we conducted a multicenter, retrospective cohort study of patients with moderate and severe coronavirus disease 19 (COVID-19), all of whom were hospitalized after being admitted to the Emergency Department (ED). We conducted our study in six major hospitals of northeast France, one of the outbreak's epicenters in Europe. A total of 1035 patients with COVID-19 were included in our study. Around three-quarters of them (76.2%) presented a moderate form of the disease, while the remaining quarter (23.8%) presented a severe form requiring admission to the ICU. At ED admission, the median LCR was significantly lower in the group presenting severe disease compared to that with moderate disease (versus 6.24 (3.24-12) versus 12.63 ((6.05-31.67)), p < 0.001). However, LCR was neither associated with disease severity (OR: 0.99, CI 95% (0.99-1)), p = 0.476) nor mortality (OR: 0.99, CI 95% (0.99-1)). In the ED, LCR, although modest, with a threshold of 12.63, was a predictive marker for severe forms of COVID-19.

Bergenin alleviates myocardial ischemia-reperfusion injury via SIRT1 signaling

Myocardial ischemia-reperfusion (MI/R) is a major risk factor for cardiovascular disease. At present, reducing oxidative stress and apoptosis is a crucial therapeutic strategy for ameliorating MI/R injury. However, there is a lack of drugs targeting oxidative stress and apoptosis for the clinical therapy of MI/R. Bergenin is a reportedly effective agent with antioxidative and antiapoptotic activity against acute injury. Nevertheless, the roles and potential mechanisms of bergenin against MI/R injury remain unknown. Here, we hypothesized that bergenin attenuated MI/R-induced apoptosis and reactive oxygen species (ROS) production via SIRT1. Mice were subjected to MI/R and treated with bergenin, after which the cardiac function, cardiomyocyte apoptosis, LDH release, and MDA content were evaluated. In vitro, myocardial injury model of H9c2 cells was induced by simulated ischemia/reperfusion (SI/R), apoptosis and oxidative stress was decreased after treated with bergenin. Bergenin significantly reduced myocardial apoptosis and ROS generation in vitro and improved cardiac function in vivo. Intriguingly, bergenin remarkably decreased apoptosis in cardiac tissue accompanied by SIRT1 upregulation following MI/R injury. Further studies showed that inhibiting SIRT1 blocked bergenin's beneficial impact against apoptosis following SI/R injury through excessive oxidative stress and depression of the Bcl2 to Bax ratio. Collectively, these findings indicate that bergenin alleviates MI/R injury by ameliorating myocardial apoptosis and oxidative damage via the SIRT1 signaling pathway.

Compound Danshen Dripping Pill inhibits hypercholesterolemia/atherosclerosis-induced heart failure in ApoE and LDLR dual deficient mice via multiple mechanisms

Heart failure is the leading cause of death worldwide. Compound Danshen Dripping Pill (CDDP) or CDDP combined with simvastatin has been widely used to treat patients with myocardial infarction and other cardiovascular diseases in China. However, the effect of CDDP on hypercholesterolemia/atherosclerosis-induced heart failure is unknown. We constructed a new model of heart failure induced by hypercholesterolemia/atherosclerosis in apolipoprotein E (ApoE) and LDL receptor (LDLR) dual deficient (ApoE^-/-LDLR^-/-) mice and investigated the effect of CDDP or CDDP plus a low dose of simvastatin on the heart failure. CDDP or CDDP plus a low dose of simvastatin inhibited heart injury by multiple actions including anti-myocardial dysfunction and anti-fibrosis. Mechanistically, both Wnt and lysine-specific demethylase 4A (KDM4A) pathways were significantly activated in mice with heart injury. Conversely, CDDP or CDDP plus a low dose of simvastatin inhibited Wnt pathway by markedly up-regulating expression of Wnt inhibitors. While the anti-inflammation and anti-oxidative stress by CDDP were achieved by inhibiting KDM4A expression and activity. In addition, CDDP attenuated simvastatin-induced myolysis in skeletal muscle. Taken together, our study suggests that CDDP or CDDP plus a low dose of simvastatin can be an effective therapy to reduce hypercholesterolemia/atherosclerosis-induced heart failure.

Digoxin use and outcomes after myocardial infarction in patients with atrial fibrillation

Digoxin is used for rate control in atrial fibrillation (AF), but evidence for its efficacy and safety after myocardial infarction (MI) is scarce and mixed. We studied post‐MI digoxin use effects on AF patient outcomes in a nationwide registry follow‐up study in Finland. Digoxin was used by 18.6% of AF patients after MI, with a decreasing usage trend during 2004–2014. Baseline differences in digoxin users (n = 881) and controls (n = 3898) were balanced with inverse probability of treatment weight adjustment. The median follow‐up was 7.4 years. Patients using digoxin after MI had a higher cumulative all‐cause mortality (77.4% vs. 72.3%; hazard ratio [HR]: 1.19; confidence interval [CI]: 1.07–1.32; p = 0.001) during a 10‐year follow‐up. Mortality differences were detected in a subgroup analysis of patients without baseline heart failure (HF) (HR: 1.23; p = 0.019) but not in patients with baseline HF (HR: 1.05; p = 0.413). Cumulative incidences of HF hospitalizations, stroke and new MI were similar between digoxin group and controls. In conclusion, digoxin use after MI is associated with increased mortality but not with HF hospitalizations, new MI or stroke in AF patients. Increased mortality was detected in patients without baseline HF. Results suggest caution with digoxin after MI in AF patients, especially in the absence of HF.

Association between dosing and combination use of medications and outcomes in heart failure with reduced ejection fraction: data from the Swedish Heart Failure Registry

AIMS

To assess the association between combination, dose and use of current guideline-recommended target doses (TD) of renin-angiotensin system inhibitors (RASi), angiotensin receptor-neprilysin inhibitors (ARNi) and β-blockers, and outcomes in a large and unselected contemporary cohort of patients with heart failure (HF) and reduced ejection fraction.

METHODS AND RESULTS

Overall, 17 809 outpatients registered in the Swedish Heart Failure Registry (SwedeHF) from May 2000 to December 2018, with ejection fraction <40% and duration of HF ≥90 days were selected. Primary outcome was a composite of time to cardiovascular death and first HF hospitalization. Compared with no use of RASi or ARNi, the adjusted hazard ratio (HR) (95% confidence interval [CI]) was 0.83 (0.76-0.91) with <50% of TD, 0.78 (0.71-0.86) with 50%-99%, and 0.73 (0.67-0.80) with ≥100% of TD. Compared with no use of β-blockers, the adjusted HR (95% CI) was 0.86 (0.76-0.91), 0.81 (0.74-0.89) and 0.74 (0.68-0.82) with <50%, 50%-99% and ≥100% of TD, respectively. Patients receiving both an angiotensin-converting enzyme inhibitor (ACEi)/angiotensin receptor blocker (ARB)/ARNi and a β-blocker at 50%-99% of TD had a lower adjusted risk of the primary outcome compared with patients only receiving one drug, i.e. ACEi/ARB/ARNi or β-blocker, even if this was at ≥100% of TD.

CONCLUSION

Heart failure with reduced ejection fraction patients using higher doses of RASi or ARNi and β-blockers had lower risk of cardiovascular death or HF hospitalization. Use of two drug classes at 50%-99% of TD dose was associated with lower risk than one drug class at 100% of TD.

The effect of sodium-glucose transport protein 2 inhibitors on mortality and heart failure in randomized trials versus observational studies

AIM

Randomized clinical trials (RCTs) allocating type 2 diabetes patients to treatment with sodium-glucose transport protein 2 (SGLT-2) inhibitors or placebo have found significant effects on the risk of heart failure and modest effects on mortality. In the wake of the first trials, a number of observational studies have been conducted, some of these reporting a mortality reduction of 50% compared to active comparators. In this review, we systematically assess and compare the results on all-cause mortality, cardiovascular mortality and heart failure hospitalization observed in RCTs with the results obtained in observational studies.

METHOD

We performed a systematic bibliographical search including cardiovascular outcome trials and observational studies assessing the effect of SGLT-2 inhibitors on mortality and heart failure.

RESULTS

Seven RCTs and 23 observational studies were included in the current review. The observed heterogeneity between study results for all-cause mortality (p-interaction < 0.001) and cardiovascular mortality (p-interaction < 0.001) was explained by study type, whereas this was not the case for heart failure (p-interaction = 0.18).

CONCLUSION

Methodological considerations such as the omission of important confounders, immortal-time bias and residual confounding such as unmeasured social economic inequality may be the cause of the inflated results observed in observational studies and that calls for caution when observational studies are used to guide treatment of patients with type 2 diabetes.

The year in cardiology: heart failure

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The Future of Meat: Health Impact Assessment with Randomized Evidence

Massive animal farming for meat production poses major problems in terms of resource use, environmental impact, and biodiversity. Furthermore, excessive meat consumption has been associated with multiple deleterious health consequences. However, more and better-designed randomized trials are needed to increase the level of evidence on the health impacts of meat. Novel meat alternatives, such as plant- and cell-based meat, are much less impactful to the environment and might replace traditional animal meat in the future, but, despite promising early data, the health consequences of these novel products need further study. This manuscript focuses on the health impacts of meat over 3 main sections: 1) overview of the evidence highlighting the association of meat consumption with health; 2) novel alternatives to meat, including plant-based and cell-based alternatives; and 3) examine the rationale for randomized studies to evaluate the effects of the novel meat alternatives compared with the standard animal meat.

Risk of Major Bleeding With Potent Antiplatelet Agents After an Acute Coronary Event: A Comparison of Ticagrelor and Clopidogrel in 5116 Consecutive Patients in Clinical Practice

Background

Major bleeding after acute coronary syndrome predicts a poor outcome but is challenging to define. The choice of antiplatelet influences bleeding risk.

Methods and Results

Major bleeding, subsequent myocardial infarction (MI), and all‐cause mortality to 1 year were compared in consecutive patients with acute coronary syndrome treated with clopidogrel (n=2491 between 2011 and 2013) and ticagrelor (n=2625 between 2012 and 2015) in 5 English hospitals. Clinical outcomes were identified from national hospital episode statistics. Bleeding and MI events were independently adjudicated by 2 experienced clinicians, blinded to drug, sequence, and year. Bleeding events were categorized using Bleeding Academic Research Consortium 3 to 5 and PLATO (Platelet Inhibition and Patient Outcomes) criteria and MI by the Third Universal Definition. Multivariable regression analysis was used to adjust outcomes for case mix. The median age was 68 years and 34% were women. 39% underwent percutaneous coronary intervention and 13% coronary artery bypass graft surgery. Clinical outcome data were 100% complete for bleeding and 99.7% for MI. No statistically significant difference was seen in crude or adjusted major bleeding for ticagrelor compared with clopidogrel (Bleeding Academic Research Consortium 3–5, hazard ratio [HR], 1.23; 95% CI, 0.90–1.68; P=0.2, PLATO major adjusted HR, 1.30; 95% CI, 0.98–1.74; P=0.07) except in the non‐coronary artery bypass graft cohort (n=4464), where bleeding was more frequent with ticagrelor (Bleeding Academic Research Consortium 3–5, adjusted HR, 1.58; 95% CI, 1.09–2.31; P=0.017; and PLATO major HR, 1.67; 95% CI, 1.18–2.37; P=0.004). There was no difference in crude or adjusted subsequent MI (adjusted HR, 1.20; 95% CI, 0.87–1.64; P=0.27). Crude mortality was higher in the clopidogrel group but not after adjustment, using either Cox proportional hazards or propensity matched population (HR, 0.90; 95% CI, 0.76–1.10; P=0.21) as was the case for stroke (HR, 0.82; 95% CI, 0.52–1.32; P=0.42).

Conclusions

This observational study indicates that the apparent benefit of ticagrelor demonstrated in a clinical trial population may not be observed in the broader population encountered in clinical practice.

Registration

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02484924.

Large-scale evidence generation and evaluation across a network of databases (LEGEND): assessing validity using hypertension as a case study

Objectives

To demonstrate the application of the Large-scale Evidence Generation and Evaluation across a Network of Databases (LEGEND) principles described in our companion article to hypertension treatments and assess internal and external validity of the generated evidence.

Materials and Methods

LEGEND defines a process for high-quality observational research based on 10 guiding principles. We demonstrate how this process, here implemented through large-scale propensity score modeling, negative and positive control questions, empirical calibration, and full transparency, can be applied to compare antihypertensive drug therapies. We assess internal validity through covariate balance, confidence-interval coverage, between-database heterogeneity, and transitivity of results. We assess external validity through comparison to direct meta-analyses of randomized controlled trials (RCTs).

Results

From 21.6 million unique antihypertensive new users, we generate 6 076 775 effect size estimates for 699 872 research questions on 12 946 treatment comparisons. Through propensity score matching, we achieve balance on all baseline patient characteristics for 75% of estimates, observe 95.7% coverage in our effect-estimate 95% confidence intervals, find high between-database consistency, and achieve transitivity in 84.8% of triplet hypotheses. Compared with meta-analyses of RCTs, our results are consistent with 28 of 30 comparisons while providing narrower confidence intervals.

Conclusion

We find that these LEGEND results show high internal validity and are congruent with meta-analyses of RCTs. For these reasons we believe that evidence generated by LEGEND is of high quality and can inform medical decision-making where evidence is currently lacking. Subsequent publications will explore the clinical interpretations of this evidence.

The Decline of the Experimental Paradigm During the COVID-19 Pandemic: A Template for the Future

The current Coronavirus Disease 2019 (COVID-19) pandemic has exerted an unprecedented impact across the globe. As a consequence of this overwhelming catastrophe, long-established prevailing medical and scientific paradigms have been disrupted. The response of the scientific community, medical journals, media, and some politicians has been far from ideal. The present manuscript discusses the failure of the scientific enterprise in its initiatives to address the COVID-19 outbreak as a consequence of the disarray attributable to haste and urgency. To enhance conveying our message, this manuscript is organized into 3 interrelated sections: 1) the accelerated pace of publications coupled with a dysfunctional review process; 2) failure of the clinical trial enterprise; 3) propagation of misleading information by the media. In response we propose a template comprising a focus on randomized controlled clinical trials, and an insistence on responsible journal publication, and enumeration of policies to deal with social media-propagated news. We conclude with a reconsideration of the appropriate role of academic medicine and journals.

Randomized Trials Versus Common Sense and Clinical Observation: JACC Review Topic of the Week

Concerns about the external validity of traditional randomized clinical trials (RCTs), together with the widespread availability of real-world data and advanced data analytic tools, have led to claims that common sense and clinical observation, rather than RCTs, should be the preferred method to generate evidence to support clinical decision-making. However, over the past 4 decades, results from well-done RCTs have repeatedly contradicted practices supported by common sense and clinical observation. Common sense and clinical observation fail for several reasons: incomplete understanding of pathophysiology, biases and unmeasured confounding in observational research, and failure to understand risks and benefits of treatments within complex systems. Concerns about traditional RCT models are legitimate, but randomization remains a critical tool to understand the causal relationship between treatments and outcomes. Instead, development and promulgation of tools to apply randomization to real-world data are needed to build the best evidence base in cardiovascular medicine.

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Well-conducted RCTs have repeatedly contradicted practices supported by common sense and clinical observation.

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Common sense and clinical observation fail because of the inability to fully understand complex biopsychosocial systems.

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RCTs must be integrated into clinical practice to improve the evidence base in cardiology.

Healthcare quality and mortality among patients hospitalized for heart failure by hospital level in Beijing, China

Aims

This study sought to compare healthcare quality and 30 day, 90 day, and 1 year mortality rates among patients admitted to secondary and tertiary hospitals for heart failure (HF) in Beijing.

Methods and results

This study retrospectively enrolled patients hospitalized with a primary discharge diagnosis of HF during January 2014 to December 2015, from five tertiary and four secondary hospitals, in Beijing, China. Mortality data were extracted from Beijing Death Surveillance Database. HF healthcare quality indices were used to evaluate in‐hospital care. Associations between hospital level and mortality rates were assessed using generalized linear mixed models, adjusting for patients' baseline characteristics and intra‐hospital correlation. Data from 1413 patients (median [interquartile range] age = 74 [65–80] years, 52.7% female) from secondary hospitals and 1250 patients (median [interquartile range] age = 72 [61–79] years, 43.3% female) from tertiary hospitals were collected. Rates of left ventricular ejection fraction assessment (73.2% vs. 90.1%) and combined use of β‐blockers and angiotensin‐converting enzyme inhibitors/angiotensin II receptor blockers (30.1% vs. 49.3%) were lower in secondary hospitals than those in tertiary hospitals, respectively. Patients admitted to secondary hospitals had a higher 90 day mortality [10.8% vs. 5.0%; adjusted odds ratio (OR): 2.06; 95% confidence interval (CI): 1.10–3.84, P = 0.024 and a higher 1 year mortality rate [21.0% vs. 12.1%; adjusted OR: 1.64; 95% CI: 1.02–2.62, P = 0.039], but 30 day mortality rates were not significantly different (5.5% vs. 3.0%; adjusted OR: 1.49; 95% CI: 0.63–3.52, P = 0.368).

Conclusions

Worse quality of care for patients with HF in secondary hospitals was associated with higher 90 day and 1 year mortality rates. Improving care quality in secondary hospitals is crucial to improve prognosis of patients they served.

Heart failure medication after a first hospital admission and risk of heart failure readmission, focus on beta-blockers and renin-angiotensin-aldosterone system medication: A retrospective cohort study in linked databases

BACKGROUND

This study assessed the association between heart failure (HF) medication (angiotensin-converting-enzyme inhibitors (ACEI)/angiotensin-receptor blockers (ARB), beta-blockers (BB), mineralocorticoid-receptor antagonists (MRA) and diuretics) and HF readmissions in a real-world unselected group of patients after a first hospital admission for HF. Furthermore we analysed readmission rates for ACEI versus ARB and for carvedilol versus β1-selective BB and we investigated the effect of HF medication in relation to time since discharge.

METHODS AND FINDINGS

Medication at discharge was determined with dispensing data from the Dutch PHARMO Database Network including 22,476 patients with HF between 2001 and 2015. After adjustment for age, gender, number of medications and year of admission no associations were found for users versus non-users of ACEI/ARB (hazard ratio, HR = 1.01; 95%CI 0.96-1.06), BB (HR = 1.00; 95%CI 0.95-1.05) and readmissions. The risk of readmission for patients prescribed MRA (HR = 1.11; 95%CI 1.05-1.16) or diuretics (HR = 1.17; 95%CI 1.09-1.25) was higher than for non-users. The HR for ARB relative to ACEI was 1.04 (95%CI 0.97-1.12) and for carvedilol relative to β1-selective BB 1.33 (95%CI 1.20-1.46). Post-hoc analyses showed a protective effect shortly after discharge for most medications. For example one month post discharge the HR for ACEI/ARB was 0.77 (95%CI 0.69-0.86). Although we did try to adjust for confounding by indication, probably residual confounding is still present.

CONCLUSIONS

Patients who were prescribed carvedilol have a higher or at least a similar risk of HF readmission compared to β1-selective BB. This study showed that all groups of HF medication -some more pronounced than others- were more effective immediately following discharge.

Late gadolinium enhancement for re-worsening left ventricular ejection fraction in patients with dilated cardiomyopathy

Aims

This study aimed to evaluate the clinical parameters including late gadolinium enhancement (LGE) of cardiovascular magnetic resonance to predict re‐worsening of left ventricular ejection fraction (LVEF) in patients with dilated cardiomyopathy (DCM).

Methods and results

We included 138 patients with recent‐onset DCM who had an LVEF <45% and underwent LGE of cardiovascular magnetic resonance imaging at diagnosis and echocardiography at the yearly follow‐up [median 6 (4–8.3) years]. Initial LVEF recovery was defined as LVEF increase >10% from baseline, resulting in LVEF ≧45% after treatment. The patients were divided into three groups: (i) improved (n = 83, 60%), defined as those with sustained LVEF ≧45%; (ii) re‐worsening (n = 39, 28%), those with >5% decrease and LVEF <45% after the initial LVEF recovery; and (iii) not‐improved (n = 16, 12%), those without initial LVEF recovery. The primary endpoint was a composite of hospitalization for heart failure or sudden cardiac death. In baseline, LGE was observed in 70 patients. The LGE area was significantly larger in the re‐worsening and not‐improved groups than that in the improved group (P < 0.001). Loess curves of long‐term LVEF trajectories showed that LVEF in the re‐worsening group increased in the first 2 years and slowly declined thereafter. Multivariate logistic regression analysis demonstrated that LGE area [odds ratio (OR) 1.09, 95% confidence interval (CI) 1.03–1.16, P = 0.004], B‐type natriuretic peptide (OR 1.49, 95% CI 1.05–2.21, P = 0.030) level at the initial recovery, and LVEF (OR 0.91, 95% CI 0.86–0.97, P = 0.004) at the initial LVEF recovery were independent predictors of re‐worsening of LVEF. During a median follow‐up of 2273 (interquartile range: 1634–3191) days, the primary endpoint was observed in 31 (22%) patients. Univariate Cox proportional hazards analysis demonstrated that the risk of experiencing the primary event in the re‐worsening group was significantly higher (hazard ratio: 4.30, 95% CI 1.63–11.31, P = 0.003) than that in the improved group and was lower than that in the not‐improved group (hazard ratio: 0.33, 95% CI 0.15–0.72, P = 0.006).

Conclusions

Re‐worsening of LVEF was observed in 28% of patients with recent‐onset DCM who showed an initial improvement in LVEF. High LGE burden, higher B‐type natriuretic peptide level, and lower LVEF at the initial LVEF recovery were independent predictors of re‐worsening of LVEF in patients with DCM. Careful observation is recommended for patients with a high risk for re‐worsening of LVEF, even in those with an initial LVEF recovery.

Digoxin-mortality: randomized vs. observational comparison in the DIG trial

AIMS

The Digitalis Investigation Group (DIG) trial, the only large randomized trial of digoxin in heart failure, reported a neutral effect on mortality and a significant reduction in heart failure hospitalizations. Recent observational studies reported increased mortality with digoxin treatment. We present further analyses of the DIG trial displaying the inability to control bias in observational treatment comparisons despite extensive statistical adjustments.

METHODS AND RESULTS

Forty-four percent of the 6800 patients in the DIG trial had been treated with digoxin before randomization, and half of them were randomly withdrawn from digoxin treatment. We contrast the main randomization-based result of the DIG trial with the observational non-randomized comparison of patients pre-treated or not pre-treated with digoxin. Mortality [hazard ratio (HR) 1.22, 95% confidence interval (CI) 1.12-1.34; P < 0.001] and heart failure hospitalizations (HR 1.47, 95% CI 1.33-1.61; P < 0.001) were significantly higher in patients pre-treated with digoxin even after adjustment for baseline population differences. The higher risks for both outcomes in those who had previously received digoxin persisted even if they received placebo during the trial (HR 1.24, 95% CI 1.10-1.40; P < 0.001). This sharply contradicts the neutral effect on mortality and the significant reduction in heart failure hospitalizations observed in the randomized comparison.

CONCLUSION

Prescription of digoxin is an indicator of disease severity and worse prognosis, which cannot be fully accounted for by covariate adjustments in the DIG trial where patients were well-characterized. It is unlikely that weaker research approaches (observational studies of administrative data or registries) can provide more reliable estimates of the effects of cardiac glycosides.

The 2020 Canadian Cardiovascular Society/Canadian Heart Rhythm Society Comprehensive Guidelines for the Management of Atrial Fibrillation

The Canadian Cardiovascular Society (CCS) atrial fibrillation (AF) guidelines program was developed to aid clinicians in the management of these complex patients, as well as to provide direction to policy makers and health care systems regarding related issues. The most recent comprehensive CCS AF guidelines update was published in 2010. Since then, periodic updates were published dealing with rapidly changing areas. However, since 2010 a large number of developments had accumulated in a wide range of areas, motivating the committee to complete a thorough guideline review. The 2020 iteration of the CCS AF guidelines represents a comprehensive renewal that integrates, updates, and replaces the past decade of guidelines, recommendations, and practical tips. It is intended to be used by practicing clinicians across all disciplines who care for patients with AF. The Grading of Recommendations, Assessment, Development and Evaluations (GRADE) system was used to evaluate recommendation strength and the quality of evidence. Areas of focus include: AF classification and definitions, epidemiology, pathophysiology, clinical evaluation, screening and opportunistic AF detection, detection and management of modifiable risk factors, integrated approach to AF management, stroke prevention, arrhythmia management, sex differences, and AF in special populations. Extensive use is made of tables and figures to synthesize important material and present key concepts. This document should be an important aid for knowledge translation and a tool to help improve clinical management of this important and challenging arrhythmia.

Principles of Large-scale Evidence Generation and Evaluation across a Network of Databases (LEGEND)

Evidence derived from existing health-care data, such as administrative claims and electronic health records, can fill evidence gaps in medicine. However, many claim such data cannot be used to estimate causal treatment effects because of the potential for observational study bias; for example, due to residual confounding. Other concerns include P hacking and publication bias. In response, the Observational Health Data Sciences and Informatics international collaborative launched the Large-scale Evidence Generation and Evaluation across a Network of Databases (LEGEND) research initiative. Its mission is to generate evidence on the effects of medical interventions using observational health-care databases while addressing the aforementioned concerns by following a recently proposed paradigm. We define 10 principles of LEGEND that enshrine this new paradigm, prescribing the generation and dissemination of evidence on many research questions at once; for example, comparing all treatments for a disease for many outcomes, thus preventing publication bias. These questions are answered using a prespecified and systematic approach, avoiding P hacking. Best-practice statistical methods address measured confounding, and control questions (research questions where the answer is known) quantify potential residual bias. Finally, the evidence is generated in a network of databases to assess consistency by sharing open-source analytics code to enhance transparency and reproducibility, but without sharing patient-level information. Here we detail the LEGEND principles and provide a generic overview of a LEGEND study. Our companion paper highlights an example study on the effects of hypertension treatments, and evaluates the internal and external validity of the evidence we generate.

Medical treatment of octogenarians with chronic heart failure: data from CHECK-HF

BACKGROUND

Elderly heart failure (HF) patients are underrepresented in clinical trials, though are a large proportion of patients in real-world practice. We investigated practice-based, secondary care HF management in a large group of chronic HF patients aged ≥ 80 years (octogenarians).

METHODS

We analyzed electronic health records of 3490 octogenarians with chronic HF at 34 Dutch outpatient clinics in the period between 2013 and 2016 , 49% women. Study patients were divided into HFpEF [LVEF ≥ 50%; n = 911 (26.1%)], HFrEF [LVEF < 40%; n = 2009 (57.6%)] and HF with mid-range EF [HFmrEF: LVEF 40-49%; n = 570 (16.3%)].

RESULTS

Most HFrEF patients aged ≥ 80 years received a beta blocker and a renin-angiotensin system (RAS) inhibitor (angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker), i.e. 78.3% and 72.8% respectively, and a mineralocorticoid receptor antagonist (MRA) was prescribed in 52.0% of patients. All three of these guideline-recommended medications (triple therapy) were given in only 29.9% of octogenarians with HFrEF, and at least 50% of target doses of triple therapy, beta blockers, RAS inhibitor and MRA, were prescribed in 43.8%, 62.2% and 53.5% of the total group of HFrEF patients. Contraindications or intolerance for beta blockers was present in 3.5% of the patients, for RAS inhibitors and MRAs in, 7.2% and 6.1% CONCLUSIONS: The majority of octogenarians with HFrEF received one or more guideline-recommended HF medications. However, triple therapy or target doses of the medications were prescribed in a minority. Comorbidities and reported contraindications and tolerances did not fully explain underuse of recommended HF therapies.

How Confident Are We about Observational Findings in Healthcare: A Benchmark Study

Healthcare professionals increasingly rely on observational healthcare data, such as administrative claims and electronic health records, to estimate the causal effects of interventions. However, limited prior studies raise concerns about the real-world performance of the statistical and epidemiological methods that are used. We present the "OHDSI Methods Benchmark" that aims to evaluate the performance of effect estimation methods on real data. The benchmark comprises a gold standard, a set of metrics, and a set of open source software tools. The gold standard is a collection of real negative controls (drug-outcome pairs where no causal effect appears to exist) and synthetic positive controls (drug-outcome pairs that augment negative controls with simulated causal effects). We apply the benchmark using four large healthcare databases to evaluate methods commonly used in practice: the new-user cohort, self-controlled cohort, case-control, case-crossover, and self-controlled case series designs. The results confirm the concerns about these methods, showing that for most methods the operating characteristics deviate considerably from nominal levels. For example, in most contexts, only half of the 95% confidence intervals we calculated contain the corresponding true effect size. We previously developed an "empirical calibration" procedure to restore these characteristics and we also evaluate this procedure. While no one method dominates, self-controlled methods such as the empirically calibrated self-controlled case series perform well across a wide range of scenarios.

Spironolactone use is associated with improved outcomes in heart failure with mid-range ejection fraction

Aims

Spironolactone has been shown to improve outcomes in patients with heart failure (HF) with reduced ejection fraction (EF). We investigated whether the discharge use of spironolactone could be associated with better long‐term outcomes among patients with HF with mid‐range EF (HFmrEF).

Methods and results

We analysed HFmrEF (left ventricular EF 40–49%) patients enrolled in the Japanese Cardiac Registry of Heart Failure in Cardiology, which prospectively studied the clinical characteristics, treatments, and long‐term outcomes of patients hospitalized due to HF. Patients were divided into two groups according to the use of spironolactone at discharge. The primary outcome was a composite of all‐cause death or HF rehospitalization. A total of 457 patients had HFmrEF. The mean age was 69.3 years and 286 (62.6%) were male. Among them, spironolactone was prescribed at discharge in 158 patients (34.6%). Chronic kidney disease (7.6% vs. 16.8%, P = 0.007) was less prevalent and loop diuretics (89.2% vs. 70.2%, P < 0.001) were more often prescribed in patients with spironolactone. During a mean follow‐up of 2.2 years, patients with spironolactone had a lower incidence rate of the primary outcome than those without it (171.5 vs. 278.8 primary outcome per 1000 patient‐years, incidence rate ratio 0.61, 95% confidence interval 0.44–0.86; P = 0.004). After multivariable adjustment, spironolactone use at discharge was associated with a significant reduction in the composite of all‐cause death or HF rehospitalization (adjusted hazard ratio 0.63, 95% confidence interval 0.44–0.90, P = 0.010).

Conclusions

Among patients with HF hospitalized for HFmrEF, spironolactone use at discharge was associated with better long‐term outcomes.

Comprehensive comparative effectiveness and safety of first-line antihypertensive drug classes: a systematic, multinational, large-scale analysis

BACKGROUND

Uncertainty remains about the optimal monotherapy for hypertension, with current guidelines recommending any primary agent among the first-line drug classes thiazide or thiazide-like diuretics, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, dihydropyridine calcium channel blockers, and non-dihydropyridine calcium channel blockers, in the absence of comorbid indications. Randomised trials have not further refined this choice.

METHODS

We developed a comprehensive framework for real-world evidence that enables comparative effectiveness and safety evaluation across many drugs and outcomes from observational data encompassing millions of patients, while minimising inherent bias. Using this framework, we did a systematic, large-scale study under a new-user cohort design to estimate the relative risks of three primary (acute myocardial infarction, hospitalisation for heart failure, and stroke) and six secondary effectiveness and 46 safety outcomes comparing all first-line classes across a global network of six administrative claims and three electronic health record databases. The framework addressed residual confounding, publication bias, and p-hacking using large-scale propensity adjustment, a large set of control outcomes, and full disclosure of hypotheses tested.

FINDINGS

Using 4·9 million patients, we generated 22 000 calibrated, propensity-score-adjusted hazard ratios (HRs) comparing all classes and outcomes across databases. Most estimates revealed no effectiveness differences between classes; however, thiazide or thiazide-like diuretics showed better primary effectiveness than angiotensin-converting enzyme inhibitors: acute myocardial infarction (HR 0·84, 95% CI 0·75-0·95), hospitalisation for heart failure (0·83, 0·74-0·95), and stroke (0·83, 0·74-0·95) risk while on initial treatment. Safety profiles also favoured thiazide or thiazide-like diuretics over angiotensin-converting enzyme inhibitors. The non-dihydropyridine calcium channel blockers were significantly inferior to the other four classes.

INTERPRETATION

This comprehensive framework introduces a new way of doing observational health-care science at scale. The approach supports equivalence between drug classes for initiating monotherapy for hypertension-in keeping with current guidelines, with the exception of thiazide or thiazide-like diuretics superiority to angiotensin-converting enzyme inhibitors and the inferiority of non-dihydropyridine calcium channel blockers.

FUNDING

US National Science Foundation, US National Institutes of Health, Janssen Research & Development, IQVIA, South Korean Ministry of Health & Welfare, Australian National Health and Medical Research Council.

The epigenome of twins as a perfect laboratory for studying behavioural traits

The debate upon the relative importance of nature vs nurture in the development of human behaviour can be traced back to ancient times. Traditional epidemiology and genetic epidemiology have confirmed the association of environmental and genetic factors with behavioural traits. Current genomic studies are identifying genetic variants associated with various behavioural traits. However, exploring the relationship of abundant environmental factors with the complex epigenome that mediates human behaviour is just at its beginning. Identical twins can serve as perfect experiments for studying the environmental impact on behavioural epigenetics advantaged by enriched power in association analysis due to controlling of their genetic make-ups. Recent development in causal inference using twin-based models adds more values in twins. This review briefly introduces the various approaches in making use of twins in studying behavioural epigenetics from experiment design to practical applications. Exploring the epigenome of twins using the powerful twin-based study designs and analytical approaches will help identifying causal epigenetic markers mediating environmental exposures and behavioural traits enabling both pharmaceutical intervention and effective prevention.

Rationale and design of the DIGIT-HF trial (DIGitoxin to Improve ouTcomes in patients with advanced chronic Heart Failure): a randomized, double-blind, placebo-controlled study

AIMS

Despite recent advances in the treatment of chronic heart failure (HF), mortality and hospitalizations still remain high. Additional therapies to improve mortality and morbidity are urgently needed. The efficacy of cardiac glycosides - although regularly used for HF treatment - remains unclear. DIGIT-HF was designed to demonstrate that digitoxin on top of standard of care treatment improves mortality and morbidity in patients with HF and a reduced ejection fraction (HFrEF).

METHODS

Patients with chronic HF, New York Heart Association (NYHA) functional class III-IV and left ventricular ejection fraction (LVEF) ≤ 40%, or patients in NYHA functional class II and LVEF ≤ 30% are randomized 1:1 in a double-blind fashion to treatment with digitoxin (target serum concentration 8-18 ng/mL) or matching placebo. Randomization is stratified by centre, sex, NYHA functional class (II, III, or IV), atrial fibrillation, and treatment with cardiac glycosides at baseline. A total of 2190 eligible patients will be included in this clinical trial (1095 per group). All patients receive standard of care treatment recommended by expert guidelines upon discretion of the treating physician. The primary outcome is a composite of all-cause mortality or hospital admission for worsening HF (whatever occurs first). Key secondary endpoints are all-cause mortality, hospital admission for worsening HF, and recurrent hospital admission for worsening HF.

CONCLUSION

The DIGIT-HF trial will provide important evidence, whether the cardiac glycoside digitoxin reduces the risk for all-cause mortality and/or hospital admission for worsening HF in patients with advanced chronic HFrEF on top of standard of care treatment.

Digitalis therapy is associated with higher comorbidities and poorer prognosis in patients undergoing ablation of atrial arrhythmias: data from the German Ablation Registry

BACKGROUND

Digitalis glycosides are employed for rate control of atrial fibrillation. Recent studies suggested potential harmful effects of digitalis monotherapy and combination with antiarrhythmic drugs. The aim of the present study was to assess the prevalence and potential impact of digitalis therapy on outcome in patients undergoing catheter ablation of supraventricular arrhythmias.

METHODS AND RESULTS

The German Ablation Registry is a nationwide, prospective registry with a 1-year follow-up investigating 12,566 patients receiving catheter ablations of supraventricular arrhythmias in 52 German centres. The present analysis focussed on pharmacotherapy in 8608 patients undergoing catheter ablation of atrial tachycardia, atrial fibrillation, or atrial flutter. Patients receiving digitalis therapy (n = 417) were older and presented a significantly increased prevalence of comorbidities including coronary artery disease, heart failure, diabetes, and pulmonary disease. One-year mortality was significantly higher in digitalis-treated patients (4.7% vs. 1.3%, p < 0.001), most strikingly in patients undergoing ablation of atrial flutter. This effect was maintained after adjustment for important risk factors. Similar results were obtained for as the combined endpoint of death, myocardial infarction, stroke and major bleeding (6.6% vs. 2.7%, p < 0.001), and non-fatal rehospitalisations (54.1% vs. 45.1%, p = 0.001).

CONCLUSION

In the present study of patients undergoing catheter ablation of supraventricular arrhythmias, an association of digitalis therapy with increased mortality and an increased rate of other severe adverse events were observed. The results from this 'real-life' registry are consistent with previously published studies. However, whether digitalis therapy promotes a poorer prognosis or may just serve as a marker for this aspect cannot be thoroughly interpreted.