Interatrial Shunt Devices

Elevated left atrial pressure during exercise is a hallmark of heart failure (HF) and is associated with adverse left atrial remodeling and poor outcomes. To decompress the pressure-overloaded left atrium in patients with HF, several device-based approaches have been developed to create a permanent, pressure-dependent, left-to-right interatrial shunt. Such approaches are currently in various stages of investigations in both HF with reduced ejection fraction (EF) and HF with preserved EF. This review discusses the evolution of the concept of left atrial decompression and summarizes the current landscape of device-based approaches used for left atrial decompression.

Sodium-glucose cotransporter-2 inhibitors in heart failure: Potential decongestive mechanisms and current clinical studies

Congestion is a key pathophysiological feature of heart failure (HF) syndrome that drives most of the clinical manifestations of acute HF and is related with poor quality of life and outcomes. Therefore, safe and effective decongestion is an important therapeutic target in the management of acute HF and despite the use of guideline-recommended loop diuretics, adequate decongestion is not always achieved in patients with acute HF. Recently, sodium-glucose cotransporter-2 (SGLT-2) inhibitors have been shown to provide clinical benefits across a broad spectrum of patients with HF, including consistent reduction in the risk of acute HF episodes. While the exact mechanisms underlying these benefits remain a matter of debate, a growing body of evidence suggests that effective decongestion may be partly responsible, especially in the setting of acute HF. In this review, we discuss the potential decongestive mechanisms of SGLT-2 inhibitors, such as osmotic diuresis, natriuresis, preservation of glomerular filtration and facilitation of interstitial drainage, which can collectively translate into effective and safe decongestion. Furthermore, we provide a comprehensive review of up-to-date clinical data of SGLT-2 inhibitor use in the acute HF population.

Device Interventions for Heart Failure

Despite remarkable advances in drug therapy for heart failure (HF), the residual HF-related morbidity, mortality, and hospitalizations remain substantial across all HF phenotypes, and significant proportions of patients with HF remain symptomatic despite optimal drug therapy. Driven by these unmet clinical needs, the exponential growth of transcatheter interventions, and a recent shift in the regulatory landscape of device-based therapies, novel device-based interventions have emerged as a potential therapy for various phenotypes of HF. Device-based interventions can overcome some of the limitations of drug therapy (eg, intolerance, nonadherence, inconsistent delivery, and recurrent and long-term cost) and can target some HF-related pathophysiologic pathways more effectively than drug therapy. This paper reviews the current evolving landscape of device-based interventions in HF and highlights critical points related to implementation of these therapies in the current workflow of HF management.

Role of the Renal Lymphatic System in Heart Failure

PURPOSE OF REVIEW

The lymphatic system plays a major but overlooked role in maintaining fluid homeostasis. Given the unique fluid homeostasis functions of the kidneys, dysregulation of the renal lymphatic system underlies the development of self-propagating congestive pathomechanisms. In this review, we outline the roles of the renal lymphatic system in heart failure (HF).

RECENT FINDINGS

Studies have uncovered several pathomechanisms involving the renal lymphatic system in congestive states, such as impaired interstitial draining by the renal lymphatic system, impaired structure and valves of renal lymphatics, lymphatic-induced increase in renal reabsorption of water and sodium, and development of albuminuria with proteinuria-induced renal lymphangiogenesis. These self-propagating mechanisms result in "renal tamponade" with manifestations of cardiorenal syndrome and inappropriate renal response to diuretics. Dysregulation of the renal lymphatic system is integral to the development and progression of congestion in HF. Targeting renal lymphatics may provide a novel pathway to treat intractable congestion.

Intravenous iron infusion in patients with heart failure: a systematic review and study-level meta-analysis

AIMS

There is considerable variability in the effect of intravenous iron on hard cardiovascular (CV)-related outcomes in patients with heart failure (HF) in randomized controlled trials (RCTs). We use a meta-analytic approach to analyse data from existing RCTs to derive a more robust estimate of the effect size of intravenous iron infusion on CV-related outcomes in patients with HF.

METHOD AND RESULTS

PubMed/Medline was searched using the following terms: ('intravenous' and 'iron' and 'heart failure') from inception till 6 November 2022 for RCTs comparing intravenous iron infusion with placebo or standard of care in patients with HF and iron deficiency. Outcomes were the composite of CV mortality and first hospitalization for HF; all-cause mortality; CV mortality; first hospitalization for HF; and total hospitalizations for HF. Random effects risk ratio (RR) with 95% confidence intervals (CIs) were calculated. Ten RCTs with a total of 3438 patients were included. Intravenous iron resulted in a significant reduction in the composite of CV mortality and first hospitalization for HF [RR 0.0.85; 95% CI (0.77, 0.95)], first hospitalization for HF [RR 0.82; 95% CI (0.67, 0.99)], and total hospitalizations for HF [RR 0.74; 95% CI (0.60, 0.91)] but no statistically significant difference in all-cause mortality [RR 0.95; 95% CI. (0.83, 1.09)] or CV mortality [OR 0.89; 95% CI (0.75, 1.05)].

CONCLUSIONS

Intravenous iron infusion in patients with HF reduces the composite risk of first hospitalization for HF and CV mortality as well as the risks of first and recurrent hospitalizations for HF, with no effect on all-cause mortality or CV mortality alone.

Post-recovery COVID-19 and incident heart failure in the National COVID Cohort Collaborative (N3C) study

Cardiac involvement has been noted in COVID-19 infection. However, the relationship between post-recovery COVID-19 and development of de novo heart failure has not been investigated in a large, nationally representative population. We examined post-recovery outcomes of 587,330 patients hospitalized in the United States (257,075 with COVID-19 and 330,255 without), using data from the National COVID Cohort Collaborative study. Patients hospitalized with COVID-19 were older (51 vs. 46 years), more often male (49% vs. 42%), and less often White (61% vs. 69%). Over a median follow up of 367 days, 10,979 incident heart failure events occurred. After adjustments, COVID-19 hospitalization was associated with a 45% higher hazard of incident heart failure (hazard ratio = 1.45; 95% confidence interval: 1.39-1.51), with more pronounced associations among patients who were younger (P-interaction = 0.003), White (P-interaction = 0.005), or who had established cardiovascular disease (P-interaction = 0.005). In conclusion, COVID-19 hospitalization is associated with increased risk of incident heart failure.

Efficacy and safety of sodium-glucose cotransporter 2 inhibitors initiation in patients with acute heart failure, with and without type 2 diabetes: a systematic review and meta-analysis

Background

There is uncertainty and limited data regarding initiation of sodium-glucose cotransporter 2 (SGLT2) inhibitors among patients hospitalized with acute heart failure (AHF). This systematic review and meta-analysis aim to establish the efficacy and safety of SGLT2 inhibitors initiated in patients hospitalized for AHF.

Methods

PubMed/Medline, Embase, and Cochrane library were searched using the following terms: (“sglt2" and "acute heart failure") and (“sglt2" and "worsening heart failure") from inception till November 15th, 2021 for randomized controlled trials (RCTs) comparing the efficacy and safety of initiating an SGLT2 inhibitor compared with placebo in patients with AHF. Major cardiovascular and diabetes scientific meetings in 2021 were also searched for relevant studies. Prespecified efficacy outcomes were all-cause mortality, rehospitalization for heart failure, and improvement in Kansas City Cardiomyopathy Questionnaire (KCCQ) scale score. Prespecified safety outcomes were acute kidney injury (AKI), hypotension, and hypoglycemia. Random effects odds ratio (OR) and mean difference with 95% confidence intervals (CIs) were calculated.

Results

Three RCTs with a total of 1831 patients were included. Initiation of SGLT2 inhibitors in patients with AHF reduced the risk of rehospitalization for heart failure (OR 0.52; 95% CI [0.42, 0.65]) and improved Kansas City Cardiomyopathy Questionnaire scores (mean difference 4.12; 95% CI [0.1.89, 6.53]). There was no statistically significant effect for initiation of SGLT2 inhibitors in patients with AHF on all-cause mortality (OR 0.70; 95% CI [0.46, 1.08]). Initiation of SGLT2 inhibitors in patients with AHF did not increase the acute kidney injury (OR 0.76; 95% CI [0.50, 1.16]), hypotension (OR 1.17; 95% CI [0.80, 1.71]), or hypoglycemia (OR 1.51; 95% CI [0.86, 2.65]).

Conclusion

Initiation of SGLT2 inhibitors in patients hospitalized for AHF during hospitalization or early post-discharge (within 3 days) reduces the risk of rehospitalization for heart failure and improves patient-reported outcomes with no excess risk of adverse effects.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-022-01455-2.

Trends and characteristics of hospitalizations for heart failure in the United States from 2004 to 2018

Aims

Hospitalization for heart failure (HF) constitutes a major healthcare and economic burden. Trends and characteristics of hospitalizations for HF for the recent years are not clear. We sought to determine the trends and characteristics of hospitalization for HF in the United States.

Method and results

A retrospective analysis of the National Inpatient Sample weighted data between 1 January 2004 and 31 December 2018, which included hospitalized adults ≥ 18 years with primary discharge diagnosis of HF using International Classification of Diseases‐9/10 administrative codes. Main outcomes were trends in hospitalizations for HF (per 1000 person) and inpatient mortality (%) between 2004 and 2018.

Conclusions

Hospitalizations for HF have been increasing across both sexes and age groups since 2013, whereas inpatient mortality has been decreasing over the study period. Blacks have the highest risk of hospitalization for HF, and Whites have the highest in‐hospital mortality. There are significant racial and geographic disparities related to hospitalizations for HF.

Prognosis for patients with heart failure and reduced ejection fraction with and without diabetes: A 7 year nationwide veteran administration analysis

OBJECTIVE

Evidence suggests diabetes mellitus is an independent risk factor for adverse cardiovascular events in patients with heart failure. As a result, we sought to compare mortality in patients with heart failure with reduced ejection fraction (HFrEF) with and without diabetes.

RESEARCH DESIGN AND METHODS

The Veteran Affairs Hospitals' databases were queried to identify all veterans diagnosed with HFrEF from 2007 to 2015. From the overall sample of 165,159 veterans, 41,120 patients with diabetes were matched by their propensity scores (without replacement) 1:1 to non-diabetic patients. To estimate the association between diabetes (Type 1 and 2) and overall mortality of HFrEF patients, a Cox proportional hazard model was used on the matched sample and controlled for patient characteristics for a mean follow up of 3.6 years (standard deviation ±2.3).

RESULTS

In a matched sample of 41,120 veterans with HFrEF with and without diabetes, those with diabetes and HFrEF were more often on guideline-directed medical therapy than those without diabetes. In the matched cohort, the mortality risk for patients with concurrent HFrEF and diabetes was 17.7% at 1 year and 74.3% at 5 years, whereas the mortality risk for those without diabetes was 15.3% at 1 year and 69.2% at 5 years. After controlling for patient characteristics such as age, sex, body mass index, heart rate, medical therapies, comorbidities, medications, low-density lipoproteins, high-density lipoproteins, we found that patients with diabetes compared to those without had a significantly increased risk of mortality (HR: 1.85, 95% CI: 1.77-1.92, p < 0.001).

CONCLUSIONS

Diabetic HFrEF patients have a higher risk of mortality than non-diabetic HFrEF patients despite controlling for medical therapies and comorbidities.

Trends in hospitalizations for heart failure, acute myocardial infarction, and stroke in the United States from 2004 to 2018

AIM

To determine the trends in hospitalizations for heart failure (HF), acute myocardial infarction (AMI), and stroke in the United States (US).

METHOD AND RESULTS

A retrospective analysis of the National Inpatient Sample weighted data between January 1, 2004 and December 31, 2018 which included hospitalized adults ≥18 years with a primary discharge diagnosis of HF, AMI, or stroke using International Classification of Diseases-9/10 administrative codes. Main outcomes were hospitalization for HF, AMI, and stroke per 1000 United States adults, length of stay, and in-hospital mortality. There were 33.4 million hospitalizations for HF, AMI, and stroke, with most being for HF (48%). After the initial decline in HF hospitalizations (5.3 hospitalizations/1000 US adults in 2004 to 4 hospitalizations/1000 US adults in 2013, P < .001), there was a progressive increase in HF hospitalizations between 2013 and 2018 (4.0 hospitalizations/1000 US adults in 2013 to 4.9 hospitalizations/1000 US adults in 2018; P < .001). Hospitalization for AMI decreased (3.1 hospitalizations/1000 US adults in 2004 to 2.5 hospitalizations/1000 US adults in 2010, P < .001) and remained stable between 2010 and 2018. There was no significant change for hospitalization for stroke between 2004 and 2011 (2.3 hospitalizations/1000 US adults in 2004 vs 2.3 hospitalizations per 1000 US adults in 2011, P = .614); however, there was a small but significant increase in hospitalization for stroke after 2011 that reached 2.5 hospitalizations/1000 US adults in 2018. Adjusted length of stay and in-hospital mortality decreased for HF, AMI, and stroke hospitalizations.

CONCLUSIONS

In contrast to the trend of AMI and stroke hospitalizations, a progressive increase in hospitalizations for HF has occurred since 2013. From 2004 to 2018, in-hospital mortality has decreased for HF, AMI, and stroke hospitalizations.

Relationship of Nonalcoholic Fatty Liver Disease and Heart Failure With Preserved Ejection Fraction

Although there is an established bidirectional relationship between heart failure with reduced ejection fraction and liver disease, the association between heart failure with preserved ejection fraction (HFpEF) and liver diseases, such as nonalcoholic fatty liver disease (NAFLD), has not been well explored. In this paper, the authors provide an in-depth review of the relationship between HFpEF and NAFLD and propose 3 NAFLD-related HFpEF phenotypes (obstructive HFpEF, metabolic HFpEF, and advanced liver fibrosis HFpEF). The authors also discuss diagnostic challenges related to the concurrent presence of NAFLD and HFpEF and offer several treatment options for NAFLD-related HFpEF phenotypes. The authors propose that NAFLD-related HFpEF should be recognized as a distinct HFpEF phenotype.

Device Therapy in Chronic Heart Failure: JACC State-of-the-Art Review

The regulatory landscape for device-based heart failure (HF) therapies has seen a major shift in the last 7 years. In 2013, the U.S. Food and Drug Administration released guidance for early feasibility and first-in-human studies, thereby encouraging device innovation, and in 2016 the U.S. Congress authorized the Breakthrough Devices Program to expedite access for Americans to innovative devices indicated for diagnosis and treatment of serious illnesses, such as HF. Since December 2016, there has been an increase in the number of HF devices for which manufacturers are seeking approval through the breakthrough designation pathway. This has led to a rapid uptake in the development and evaluation of device-based HF therapies. This article reviews the current and future landscape of device therapies for chronic HF and associated comorbidities and the regulatory environment that is driving current and future innovation.

Lymphatic Dysregulation in Patients With Heart Failure: JACC Review Topic of the Week

The lymphatic system is an integral part of the circulatory system and plays an important role in the volume homeostasis of the human body. The complex anatomy and physiology paired with a lack of simple diagnostic tools to study the lymphatic system have led to an underappreciation of the contribution of the lymphatic system to acute and chronic heart failure (HF). Herein, we discuss the physiological role of the lymphatic system in volume management and the evidence demonstrating the dysregulation of the lymphatic system in HF. Further, we discuss the opportunity to target the lymphatic system in the management of HF and different potential approaches to accessing the lymphatic system.

Direct Oral Anticoagulants Versus Warfarin in Left Ventricular Thrombus: A Systematic Review and Meta-Analysis

BACKGROUND

There are conflicting results regarding the safety and efficacy of direct oral anticoagulants (DOACs) in the management of left ventricular thrombus (LVT) compared with the vitamin K antagonist warfarin.

STUDY QUESTION

What is the safety and efficacy of DOACs in the management of LVT compared with warfarin?

DATA SOURCE

Randomized clinical trials and cohort studies in the MEDLINE and Cochrane databases from inception till April 4, 2021.

STUDY DESIGN

The present analysis is a systematic review and meta-analysis. Desired outcomes were all-cause mortality, complete resolution of LVT, stroke and systemic emboli, and major bleeding. The risk ratio (RR) of the outcomes and 95% confidence intervals (CIs) were calculated using a random-effects modeling approach.

RESULTS

Twelve studies with a total of 2322 patients were included. There was no difference between the 2 interventions in the resolution of LVT [RR 0.97 (CI 0.93-1.02)], stroke and systemic embolism [RR 0.95 (CI 0.63-1.45)], bleeding [RR 1.14 (CI 0.81-1.60)], and all-cause mortality [RR 0.99 (CI 0.67, 1.46)].

CONCLUSIONS

DOACs and warfarin have comparable safety and efficacy outcomes in the management of LVT.

Causes of hospitalization in the USA between 2005 and 2018

In this report, we identify the 10 most common causes of hospitalizations in the USA in 2005–2018 using the discharge data from the National Inpatient Sample database. We show that sepsis has been the leading cause of hospitalizations in the USA followed by heart failure, which has consistently been within the three most common causes of hospitalizations since 2005. In addition, we show a high burden of cardiovascular diseases as a cause of hospitalization over the study period with a consistent presence of cardiac arrhythmias as one of the top 10 causes of hospitalizations in the USA and emergence of acute myocardial infarction as one of the top 10 causes after 2014.

Effects of sodium-glucose cotransporter 1 and 2 inhibitors on cardiovascular and kidney outcomes in type 2 diabetes: A meta-analysis update

In this report, we aim to provide an updated meta-analysis of the sodium-glucose cotransporter 2 (SGLT2) inhibitors trial data with the new trial data on sotagliflozin, a first-in-class dual SGLT1 and SGLT2 inhibitor. We searched Medline, Cochrane library, and Embase databases for randomized clinical trials comparing cardiovascular and kidney outcomes between SGLT2 and dual SGLT1/2 inhibitors and placebo. Nine randomized clinical trials with a total of 60,914 patients with type 2 diabetes were included. In patients with type 2 diabetes, the use of SGLT2 and dual SGLT1/2 inhibitors improves the cardiovascular and kidney outcome.

Effect of sodium-glucose cotransporter 2 inhibitors on cardiovascular and kidney outcomes-Systematic review and meta-analysis of randomized placebo-controlled trials

Sodium-glucose cotransporter 2 inhibitor (SGLT2i) use is associated with improved cardiovascular and kidney outcomes. However, the magnitude and potential heterogeneity of effect across patients with varying types of cardiometabolic and kidney disease is unclear. To examine the effect of SGLT2i on cardiovascular and kidney outcomes among patients with type 2 diabetes mellitus (T2DM), and independent of T2DM status, among patients with heart failure (HF), and chronic kidney disease.

METHOD

Medline, Embase, Cochrane library and scientific conferences were searched from inception till September 24, 2020 for randomized controlled trials comparing cardiovascular and kidney outcomes between SGLT2i and placebo. Random effects hazard ratios (HR) with 95% confidence intervals (CIs) were calculated.

RESULTS

Eight trials with a combined 59,747 patients were included. In the overall population, SGLT2i reduced the risk of all-cause mortality (HR 0.84; 95% CI [0.78-0.91]), cardiovascular mortality (HR 0.84; 95% CI [0.76-0.93]) hospitalization for HF (HR 0.69; 95% CI [0.64-0.74]), myocardial infarction (HR 0.91; 95% CI [0.84-0.99]), and composite kidney outcome (HR 0.62; 95% CI [0.56-0.70]). There was no significant effect on the risk of stroke (HR 0.98; 95% CI [0.86-1.11]). Results were consistent across subgroups stratified by diabetes and HF status. SGLT2i use was not associated with a greater risk of hypoglycemia (OR 0.92; 95% CI [0.84-1.01]) or amputation (OR 1.25; 95% CI [0.97-1.62]). There were 64 diabetic ketoacidosis events with SGLT2i use and 18 with placebo (OR 2.86; 95% CI [1.39-5.86]).

CONCLUSIONS

In patients with cardiometabolic and kidney disease, SGLT2i improved cardiovascular and kidney outcomes, regardless of T2DM, HF, and/or CKD status. The magnitude of risk reduction was largest for hospitalization for HF and progression of kidney disease, more modest for mortality and MI and absent for stroke.

Dissecting myocardial mechanics in patients with severe aortic stenosis: 2-dimensional vs 3-dimensional-speckle tracking echocardiography

Background

Aortic stenosis (AS) causes left ventricular (LV) pressure overload, leading to adverse LV remodeling and dysfunction. Identifying early subclinical markers of LV dysfunction in patients with significant AS is critical as this could provide support for earlier intervention, which may result in improved long-term outcomes. We therefore examined the impact of severe AS and its consequent increase in LV afterload on myocardial deformation and rotational mechanics by 2-dimensional (2D) and 3-dimensional (3D) speckle-tracking echocardiography.

Methods

We prospectively measured various strain parameters in 168 patients (42% female, mean age 72 ± 12 years) with severe AS and LV ejection fraction (EF) ≥50%, and compared them to normal values found in literature. 2D and 3D images were analyzed for global longitudinal strain (GLS), global circumferential strain (GCS), global radial strain (GRS), basal rotation, apical rotation, and peak systolic twist. We further assessed the degree of concordance between 2D and 3D strain, and examined their association with measures of LV preload and afterload.

Results

Patients with severe AS exhibited significantly lower GLS and GRS but higher GCS, apical rotation, and twist by 2D and 3D echocardiography compared with published normal values (P = 0.003 for 3D twist, P < 0.001 for all others). Agreement between 2D- and 3D-GLS by concordance correlation coefficient was 0.49 (95% confidence interval: 0.39–0.57). GLS was correlated with valvulo-arterial impedance, a measure of LV afterload (r = 0.34, p < 0.001 and r = 0.23, p = 0.003, respectively).

Conclusion

Patients with severe AS demonstrated lower-than-normal GLS and GRS but appear to compensate with higher-than-normal GCS, apical rotation, and twist in order to maintain a preserved LVEF. GLS showed a modest correlation with valvulo-arterial impedance.

Renin-Angiotensin System Blockade and Mortality in Patients With Hypertension and COVID-19 Infection

To determine the effect renin-angiotensin system blockers on the outcome in patients with hypertension and concurrent COVID-19 infection, we searched PubMed, the Cochrane Library, and Google Scholar for relevant articles. Twelve studies with a total of 16,101 patients met the inclusion criteria. The mortality rate among the users of angiotensin converting enzyme inhibitors or angiotensin receptor blockers was 12.15% and in non-users it was 14.56% (risk ratio 0.70, 95% CI [0.53-0.91], P < 0.007). There was no difference in the risk of death between the use of angiotensin converting enzyme inhibitors and angiotensin receptor blockers (risk ratio 1.09, 95% CI [0.90 -1.32]). We conclude that the use of angiotensin converting enzyme inhibitors and angiotensin receptor blockers improves mortality in patients with hypertension and concurrent COVID-19 infection, without a significant difference between ACEIs and ARBs in this population.

Hypothesis: Sex-Related Differences in ACE2 Activity May Contribute to Higher Mortality in Men Versus Women With COVID-19

Angiotensin-converting enzyme 2 (ACE2) facilitates the cellular entry of the severe acute respiratory syndrome-associated coronavirus 2 (SARS-CoV-2), which causes the coronavirus-2019 (COVID-19) disease. Recent reports have shown worse outcomes in men with COVID-19 infection compared to women. We review the hypothesis that sex-related differences in outcomes in COVID-19 are due to different activity of ACE2 between men and women. We also show that studies in humans have demonstrated no significant difference in serum ACE2 levels between healthy men and women. However, men with hypertension and heart failure typically have higher level of serum ACE2 activity compared to women. We hypothesize that the worse outcomes in men with COVID-19 compared to women is likely due to higher prevalence of hypertension and heart failure among men compared to women. To test this hypothesis, studies to compare the outcomes of COVID-19 infection between men and women with no preexisting heart diseases are needed.

Smoking Doubles the Mortality Risk in COVID-19: A Meta-Analysis of Recent Reports and Potential Mechanisms

Introduction

Studies have reported conflicting results regarding the effect of smoking on outcome in coronavirus disease 2019 (COVID-19) patients, but the results have been conflicting. In this meta-analysis, we systematically examined the association between smoking and mortality in COVID-19.

Methods

PubMed database was searched to look for relevant articles. Inclusion criteria were as follows: (1) cohort studies or case series studies; (2) study population included individuals with a confirmed COVID-19 infection; (3) the status of smoking was reported, regardless if it was current or in the past; and (4) mortality among smokers was reported in the study or could be calculated and compared to non-smokers. Mortality rates were pooled using a random effects model. Risk ratio (RR) and its 95% confidence interval (CI) were also calculated using the same model. Another meta-analysis was then performed to assess the difference in mortality between current and former smokers.

Results

Ten studies with a total of 11,189 patients were included. Mortality among smokers was 29.4% compared to 17.0% among non-smokers. RR was 2.07 (95% CI: 1.59, 2.69). Based on analysis of four studies (532 patients), there was no difference in mortality risk between current and former smokers (RR: 1.03; 95% CI: 0.75, 1.40).

Conclusions

Smoking, current or past, is associated with higher mortality in COVID-19 patients. Mortality among current smokers was about 50% greater than former smokers, but the difference was not statistically significant.