Oliver J. Ziff

Safety and efficacy of digoxin: systematic review and meta-analysis of observational and controlled trial data

Objective To clarify the impact of digoxin on death and clinical outcomes across all observational and randomised controlled trials, accounting for study designs and methods. Data sources and study selection Comprehensive literature search of Medline, Embase, the Cochrane Library, reference lists, and ongoing studies according to a prospectively registered design (PROSPERO: CRD42014010783), including all studies published from 1960 to July 2014 that examined treatment with digoxin compared with control (placebo or no treatment). Data extraction and synthesis Unadjusted and adjusted data pooled according to study design, analysis method, and risk of bias. Main outcome measures Primary outcome (all cause mortality) and secondary outcomes (including admission to hospital) were meta-analysed with random effects modelling. Results 52 studies were systematically reviewed, comprising 621 845 patients. Digoxin users were 2.4 years older than control (weighted difference 95% confidence interval 1.3 to 3.6), with lower ejection fraction (33% v 42%), more diabetes, and greater use of diuretics and anti-arrhythmic drugs. Meta-analysis included 75 study analyses, with a combined total of 4 006 210 patient years of follow-up. Compared with control, the pooled risk ratio for death with digoxin was 1.76 in unadjusted analyses (1.57 to 1.97), 1.61 in adjusted analyses (1.31 to 1.97), 1.18 in propensity matched studies (1.09 to 1.26), and 0.99 in randomised controlled trials (0.93 to 1.05). Meta-regression confirmed that baseline differences between treatment groups had a significant impact on mortality associated with digoxin, including markers of heart failure severity such as use of diuretics (P=0.004). Studies with better methods and lower risk of bias were more likely to report a neutral association of digoxin with mortality (P<0.001). Across all study types, digoxin led to a small but significant reduction in all cause hospital admission (risk ratio 0.92, 0.89 to 0.95; P<0.001; n=29 525). Conclusions Digoxin is associated with a neutral effect on mortality in randomised trials and a lower rate of admissions to hospital across all study types. Regardless of statistical analysis, prescription biases limit the value of observational data.

Digoxin: The good and the bad

After 230 years of use, digitalis remains an important and useful therapy for patients with atrial fibrillation, heart failure, and the 30-50 % of patients with both conditions. Although the combination of positive inotropic activity with negative chronotropic effects has been shown to reduce hospital admissions in heart failure, there is a distinct lack of robust trial data, particularly in patients with atrial fibrillation. We recently performed a comprehensive meta-analysis of all digoxin studies and demonstrated a neutral effect on mortality. This contradicts prior observational data that overlook the fact that digitalis is usually given as second-line therapy to the sickest patients. Use of these agents in clinical practice should take account of appropriate dose, serum concentration, drug interactions, and potential side effects. The aim of this review is to evaluate the evidence base for cardiac glycosides and provide a pragmatic guide to their advantages and disadvantages.

Remote ischaemic conditioning reduces infarct size in animal in vivo models of ischaemia-reperfusion injury: a systematic review and meta-analysis

Aims The potential of remote ischaemic conditioning (RIC) to ameliorate myocardial ischaemia-reperfusion injury (IRI) remains controversial. We aimed to analyse the pre-clinical evidence base to ascertain the overall effect and variability of RIC in animal in vivo models of myocardial IRI. Furthermore, we aimed to investigate the impact of different study protocols on the protective utility of RIC in animal models and identify gaps in our understanding of this promising therapeutic strategy. Methods and results Our primary outcome measure was the difference in mean infarct size between RIC and control groups in in vivo models of myocardial IRI. A systematic review returned 31 reports, from which we made 22 controlled comparisons of remote ischaemic preconditioning (RIPreC) and 21 of remote ischaemic perconditioning and postconditioning (RIPerC/RIPostC) in a pooled random-effects meta-analysis. In total, our analysis includes data from 280 control animals and 373 animals subject to RIC. Overall, RIPreC reduced infarct size as a percentage of area at risk by 22.8% (95% CI 18.8–26.9%), when compared with untreated controls (P < 0.001). Similarly, RIPerC/RIPostC reduced infarct size by 22.2% (95% CI 17.1–25.3%; P < 0.001). Interestingly, we observed significant heterogeneity in effect size (T2 = 92.9% and I2 = 99.4%; P < 0.001) that could not be explained by any of the experimental variables analysed by meta-regression. However, few reports have systematically characterized RIC protocols, and few of the included in vivo studies satisfactorily met study quality requirements, particularly with respect to blinding and randomization. Conclusions RIC significantly reduces infarct size in in vivo models of myocardial IRI. Heterogeneity between studies could not be explained by the experimental variables tested, but studies are limited in number and lack consistency in quality and study design. There is therefore a clear need for more well-performed in vivo studies with particular emphasis on detailed characterization of RIC protocols and investigating the potential impact of gender. Finally, more studies investigating the potential benefit of RIC in larger species are required before translation to humans.

Individualized approaches to thromboprophylaxis in atrial fibrillation

Atrial fibrillation (AF) is the most common arrhythmia worldwide. The prevalence of AF in persons older than 55 years is at least 33.5 million globally and is predicted to more than double in the next half-century. Anticoagulation, heart rate control, and heart rhythm control comprise the 3 main treatment strategies in AF. Anticoagulation is aimed at preventing debilitating stroke, systemic embolism, and associated mortality. Historically, anticoagulation in AF was achieved with a vitamin K antagonist such as warfarin, which is supported by evidence demonstrating reduced incident stroke and all-cause mortality. However, warfarin has unpredictable pharmacokinetics with many drug-drug interactions that require regular monitoring to ensure patients remain in the therapeutic anticoagulant range. Non-vitamin K antagonist oral anticoagulants including dabigatran, rivaroxaban, apixaban, and edoxaban provide a possible solution to these issues with their more predictable pharmacokinetics, rapid onset of action, and greater specificity. Results from large randomized, controlled trials indicate that these agents are at least noninferior to warfarin in prevention of stroke. These trials also demonstrate a consistently lower incidence of intracranial hemorrhage, almost always all life-threatening bleeds, and many forms of major bleeds with the possible exception of gastrointestinal and some other forms of mucosal bleeding, compared with warfarin. Patients with AF are a heterogeneous population with diverse risk of stroke and bleeding, and different subgroups respond differently to anticoagulation. Important clinical questions have arisen regarding optimal anticoagulation drug selection in distinct populations such as those with renal impairment, older age, coronary artery disease, and heart failure as well as those at particularly high risk for bleeding or thromboembolism. In this review, treatment strategies in AF management are discussed in the context of different individual subgroups of patients.

The interplay between atrial fibrillation and heart failure on long-term mortality and length of stay: Insights from the, United Kingdom ACALM registry

BACKGROUND There is concern that the development of heart failure and atrial fibrillation has a detrimental influence on clinical outcomes. The aim of this study was to assess all-cause mortality and length of hospital stay in patients with chronic and new-onset concomitant AF and HF. METHODS Using the ACALM registry, we analysed adults hospitalised between 2000 and 2013 with AF and HF and assessed prevalence, mortality and length of hospital stay. Patients with HF and/or AF at baseline (study-entry) were compared with patients who developed new-onset disease during follow-up. RESULTS Of 929,552 patients, 31,695 (3.4%) were in AF without HF, 20,768 (2.2%) had HF in sinus rhythm, and 10,992 (1.2%) had HF in AF. Patients with HF in AF had the greatest all-cause mortality (70.8%), followed by HF in sinus rhythm (64.1%) and AF alone (45.1%, p<0.0001). Patients that developed new-onset AF, HF or both had significantly worse mortality (58.5%, 70.7% and 74.8% respectively) compared to those already with the condition at baseline (48.5%, 63.7% and 67.2% respectively, p<0.0001). Patients with HF in AF had the longest length of hospital stay (9.41days, 95% CI 8.90-9.92), followed by HF in sinus rhythm (7.67, 95% CI 7.34-8.00) and AF alone (6.05, 95% CI 5.78-6.31). CONCLUSIONS Patients with HF in AF are at a greater risk of mortality and longer hospital stay compared to patients without the combination. New-onset AF or HF is associated with significantly worse prognosis than long-standing disease.

Impact of seasonality on the dynamics of native Vitamin D repletion in long-term renal transplant patients

Abstract Background: Renal transplant recipients (RTRs) are often Vitamin D (VitD) depleted as a result of both chronic kidney disease and mandated sun avoidance behaviours. Repleting VitD may be warranted, but how, and for how long, is unknown, as is the impact of seasonality on the success of repletion. We investigated the impact of seasonality on VitD status following VitD repletion in a large cohort of stable, long-term RTRs. Methods: Serum 25-hydroxyvitamin D [25(OH)D] concentrations and bone biochemistry parameters were analysed from 102 VitD repletion courses in 98 RTRs that had undergone VitD repletion. Repletion was delivered over 6 months with either 240 000 IU colecalciferol if pre-repletion serum VitD was between 20 and 50 nmol/L, or with 360 000 IU if VitD was <20 nmol/L. Twelve months post-repletion 25(OH)D and parathyroid hormone (PTH) were available for 75 patients. Results: At baseline, 25(OH)D was 20.1 ± 1.0 nmol/L, increasing to 65.4 ± 1.8 nmol/L following repletion (+7.55 nmol/L/month, P < 0.0001). Twelve months post-repletion and after no further VitD administration, 25(OH)D fell to 35.4 ± 1.8 nmol/L (14.2 ± 0.7 ng/mL; −2.50 nmol/L/month, P < 0.0001). PTH followed the opposite trend with baseline, repletion-end and post-repletion values being 144.2 ± 12.0, 109.6 ± 7.5 and 129.2 ± 11.4 ng/L, respectively. VitD repletion during the summer was associated with significantly higher at repletion-end 25(OH)D compared with any other time of year [summer 80.9 ± 4.0, autumn 64.1 ± 3.0 (P = 0.002), winter 48.9 ± 3.0 (P <0.001), spring 63.8 ± 2.5 nmol/L (P <0.001)]. There was no hypercalcaemia during repletion and renal transplant function remained stable without any evidence of allograft rejection. Conclusions: VitD repletion can safely and effectively be achieved in the majority of chronic stable RTRs using a 6-month bolus intermediate-dose schedule. Winter repletion is associated with an inadequate response in 25(OH)D; however, all patients experience a post-repletion fall towards deficiency in the absence of maintenance supplementation, irrespective of the season of repletion.

Calibrating the impact of dual RAAS blockade on the heart and the kidney – balancing risks and benefits

Overactivity of the renin–angiotensin–aldosterone system (RAAS) plays a key role in the pathophysiology of heart failure (HF) and chronic kidney disease (CKD). RAAS antagonists can significantly improve clinical outcomes, but monotherapy blocks but one step of the RAAS and can be bypassed through compensatory mechanisms. Providing more complete RAAS blockade by deploying drugs with complementary actions seemed logical – hence the practice of using dual (or triple) RAAS inhibitors. However, RAAS antagonists also exhibit dose‐limiting side effects, including acute kidney injury, hyperkalaemia and hypotension, which blunt their overall effectiveness. Despite achieving better RAAS blockade, several trials failed to show clinical outcome improvements. Patients with concomitant CKD and HF (cardiorenal syndrome) are at the greatest risk of these adverse events and therefore the least able to benefit, yet they also have the worst prognosis. This paradox, where those most in need have fewest therapeutic options, poses three questions which are the focus of this review: whether (i) novel therapies that prevent adverse effects can restore therapeutic benefits to patients who would otherwise be RAAS‐therapy intolerant, (ii) there are any validated alternatives to their use and (iii) newer approaches to the detection of fluid congestion are ready for implementation.

Therapeutic strategies utilizing SDF-1α in ischaemic cardiomyopathy

Abstract Heart failure is rapidly increasing in prevalence and will redraw the global landscape for cardiovascular health. Alleviating and repairing cardiac injury associated with myocardial infarction (MI) is key to improving this burden. Homing signals mobilize and recruit stem cells to the ischaemic myocardium where they exert beneficial paracrine effects. The chemoattractant cytokine SDF-1α and its associated receptor CXCR4 are upregulated after MI and appear to be important in this context. Activation of CXCR4 promotes both cardiomyocyte survival and stem cell migration towards the infarcted myocardium. These effects have beneficial effects on infarct size, and left ventricular remodelling and function. However, the timing of endogenous SDF-1α release and CXCR4 upregulation may not be optimal. Furthermore, current ELISA-based assays cannot distinguish between active SDF-1α, and SDF-1α inactivated by dipeptidyl peptidase 4 (DPP4). Current therapeutic approaches aim to recruit the SDF-1α-CXCR4 pathway or prolong SDF-1α life-time by preventing its cleavage by DPP4. This review assesses the evidence supporting these approaches and proposes SDF-1α as an important confounder in recent studies of DPP4 inhibitors.

The Magnum Opus: Near-peer teaching combined with questions banks

Dear SirWe read with interest the article published by Gooi & Sommerfeld (2015), suggesting a new era of medical school, “Medical School 2.0”, that can be achieved by developing a student-generated...

21 Impact of Combined Atrial Fibrillation and Heart Failure on Mortality: 14 Year Naturalistic Follow-Up Study

Background Atrial Fibrillation (AF) and Heart Failure (HF) frequently co-exist conferring considerable morbidity and mortality, yet current treatment options remain limited. Recent meta-analyses of patients with concomitant AF and HF have suggested no prognostic benefit of beta-blockers or digoxin, creating a paradox whereby those most in need have the fewest therapeutic choices. We sought to investigate the association between HF and AF and their impact on mortality from a large 14-year naturalistic follow-up study. Methods Anonymous data of adult patients aged ≥18 with all types of HF and AF admitted to several hospitals in the North of England between 2000 and 2013 was obtained and processed using the ACALM (Algorithm for Co-morbidity, Associations, Length of stay and Mortality) study protocol. ACALM uses the ICD-10 and OPCS-4 coding systems to identify patients and the methodology has been published widely. Analyses were performed comparing mortality between patients with HF, AF and combined HF and AF at baseline and their development during follow-up. Results At baseline, of 929,552 adult patients 29,164 (3.1%) had AF, 19,474 (2.1%) had HF, and 5,728 (0.6%) had both HF and AF. Of those with AF at baseline, 1,647 (5.6%) developed HF during follow-up, and of those with HF at baseline, 824 (4.2%) developed AF during follow-up. Demographics and crude mortality rates are shown; see Table. Patients with combined AF and HF at baseline had increased mortality than patients with AF or HF alone. Patients with AF at baseline that developed HF, and patients with HF at baseline that developed AF, experienced a greater mortality compared to those with combined HF and AF at baseline; see Figure.Abstract 21 Table 1 Characteristics of ACLM participants by atrial fibrillation and heart failure status at the start and end of the study Baseline AF Baseline HF BaselineAF + HF Baseline AF,developed HF Baseline HF,developed AF n 29164 19474 5728 1647 824 Age ± SD 74 ± 13 73 ± 14 77 ± 12 77 ± 11 77 ± 11 Male% 52.4 51.0 49.8 48.0 49.3 Caucasian% 87.6 82.9 86.8 92.2 90.2 South Asian% 1.7 4.0 1.8 1.6 2.4 Afro-Caribbean% 0.8 1.6 1.2 0.4 0.6 Other% 9.9 11.8 10.2 5.8 6.8 Crude Mortality (per 1000) 485 636 672 715 778 Mean Survival (Days) 722 631 692 880 922 AF, atrial fibrillation; HF, heart failure; SD, standard deviationAbstract 21 Figure 1 Kaplan Meier survival curves through the duration of follow-up in the ACALM database are shown based on atrial fibrillation and heart failure status at the start and end of the study. AF, atrial fibrillation; HF, heart failure Conclusion Concomitant AF and HF is associated with substantial mortality and risk of death, irrespective of which disease develops first. In light of limited current treatment for these patients, future therapies to specifically target the combined HF and AF group are required.