Association between statin use and mortality in patients with implantable cardioverter-defibrillators and left ventricular systolic dysfunction

Influence of diabetes on mortality and ICD therapies in ICD recipients: a systematic review and meta-analysis of 162,780 patients

Background

The influence of diabetes on the mortality and risk of implantable cardioverter defibrillator (ICD) therapies is still controversial, and a comprehensive assessment is lacking. We performed this systematic review and meta-analysis to address this controversy.

Methods

We systematically searched the PubMed, Embase, Web of Science and Cochrane Library databases to collect relevant literature. Fixed and random effects models were used to estimate the hazard ratio (HR) with 95% CIs.

Results

Thirty-six articles reporting on 162,780 ICD recipients were included in this analysis. Compared with nondiabetic ICD recipients, diabetic ICD recipients had higher all-cause mortality (HR = 1.45, 95% CI 1.36–1.55). The subgroup analysis showed that secondary prevention patients with diabetes may suffer a higher risk of all-cause mortality (HR = 1.89, 95% CI 1.56–2.28) (for subgroup analysis, P = 0.03). Cardiac mortality was also higher in ICD recipients with diabetes (HR = 1.68, 95% CI 1.35–2.08). However, diabetes had no significant effect on the risks of ICD therapies, including appropriate or inappropriate therapy, appropriate or inappropriate shock and appropriate anti-tachycardia pacing (ATP). Diabetes was associated with a decreased risk of inappropriate ATP (HR = 0.56, 95% CI 0.39–0.79).

Conclusion

Diabetes is associated with an increased risk of mortality in ICD recipients, especially in the secondary prevention patients, but does not significantly influence the risks of ICD therapies, indicating that the increased mortality of ICD recipients with diabetes may not be caused by arrhythmias. The survival benefits of ICD treatment in diabetes patients are limited.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-022-01580-y.

Therapeutic implications of statins in heart failure with reduced ejection fraction and heart failure with preserved ejection fraction: a review of current literature

Statins are one of the standard treatments to prevent cardiovascular events such as coronary artery disease and heart failure (HF). However, data on the use of statins to improve clinical outcomes in patients with established HF remains controversial. We summarized available clinical studies which investigated the effects of statins on clinical outcomes in patients with HF with reduced ejection fraction (HFrEF) and HF with preserved ejection fraction (HFpEF). Statins possess many pleiotropic effects in addition to lipid-lowering properties that positively affect the pathophysiology of HF. In HFrEF, data from two large randomized placebo-controlled trials did not show benefits of statins on mortality of patients with HFrEF. However, more recent prospective cohort studies and meta-analyses have shown decreased risk of mortality as well as cardiovascular hospitalization with statins treatment. In HFpEF, most prospective and retrospective cohort studies as well as meta analyses have consistently reported positive effects of statins, including reducing mortality and improving other clinical outcomes. Current evidence also suggests better outcomes with lipophilic statins in patients with HF. In summary, statins might be effective in improving survival and other clinical outcomes in patients with HF, especially for patients with HFpEF. Lipophilic statins might also be more beneficial for HF patients. Based on current evidence, statins did not cause harm and should be continued in HF patients who are already taking the medication. Further randomized controlled trials are needed to clarify the benefits of statins in HF patients.

Association of statin use and clinical outcomes in heart failure patients: a systematic review and meta-analysis

BACKGROUND

The role of statins in patients with heart failure (HF) of different levels of left ventricular ejection fraction (LVEF) remains unclear especially in the light of the absence of prospective data from randomized controlled trials (RCTs) in non-ischemic HF, and taking into account potential statins' prosarcopenic effects. We assessed the association of statin use with clinical outcomes in patients with HF.

METHODS

We searched PubMed, EMBASE, Scopus, Google Scholar and Cochrane Central until August 2018 for RCTs and prospective cohorts comparing clinical outcomes with statin vs non-statin use in patients with HF at different LVEF levels. We followed the guidelines of the 2009 PRISMA statement for reporting and applied independent extraction by multiple observers. Meta-analyses of hazard ratios (HRs) of effects of statins on clinical outcomes used generic inverse variance method and random model effects. Clinical outcomes were all-cause mortality, cardiovascular (CV) mortality and CV hospitalization.

RESULTS

Finally we included 17 studies (n = 88,100; 2 RCTs and 15 cohorts) comparing statin vs non-statin users (mean follow-up 36 months). Compared with non-statin use, statin use was associated with lower risk of all-cause mortality (HR 0.77, 95% confidence interval [CI], 0.72-0.83, P < 0.0001, I2 = 63%), CV mortality (HR 0.82, 95% CI: 0.76-0.88, P < 0.0001, I2 = 63%), and CV hospitalization (HR 0.78, 95% CI: 0.69-0.89, P = 0.0003, I2 = 36%). All-cause mortality was reduced on statin therapy in HF with both EF < 40% and ≥ 40% (HR: 0.77, 95% Cl: 0.68-0.86, P < 0.00001, and HR 0.75, 95% CI: 0.69-0.82, P < 0.00001, respectively). Similarly, CV mortality (HR 0.86, 95% CI: 0.79-0.93, P = 0.0003, and HR 0.83, 95% CI: 0.77-0.90, P < 0.00001, respectively), and CV hospitalizations (HR 0.80 95% CI: 0.64-0.99, P = 0.04 and HR 0.76 95% CI: 0.61-0.93, P = 0.009, respectively) were reduced in these EF subgroups. Significant effects on all clinical outcomes were also found in cohort studies' analyses; the effect was also larger and significant for lipophilic than hydrophilic statins.

CONCLUSIONS

In conclusion, statins may have a beneficial effect on CV outcomes irrespective of HF etiology and LVEF level. Lipophilic statins seem to be much more favorable for patients with heart failure.

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

Aims

Treatment 'effects' are often inferred from non-randomized and observational studies. These studies have inherent biases and limitations, which may make therapeutic inferences based on their results unreliable. We compared the conflicting findings of these studies to those of prospective randomized controlled trials (RCTs) in relation to pharmacological treatments for heart failure (HF).

Methods and results

We searched Medline and Embase to identify studies of the association between non-randomized drug therapy and all-cause mortality in patients with HF until 31 December 2017. The treatments of interest were: angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, beta-blockers, mineralocorticoid receptor antagonists (MRAs), statins, and digoxin. We compared the findings of these observational studies with those of relevant RCTs. We identified 92 publications, reporting 94 non-randomized studies, describing 158 estimates of the 'effect' of the six treatments of interest on all-cause mortality, i.e. some studies examined more than one treatment and/or HF phenotype. These six treatments had been tested in 25 RCTs. For example, two pivotal RCTs showed that MRAs reduced mortality in patients with HF with reduced ejection fraction. However, only one of 12 non-randomized studies found that MRAs were of benefit, with 10 finding a neutral effect, and one a harmful effect.

Conclusion

This comprehensive comparison of studies of non-randomized data with the findings of RCTs in HF shows that it is not possible to make reliable therapeutic inferences from observational associations. While trials undoubtedly leave gaps in evidence and enrol selected participants, they clearly remain the best guide to the treatment of patients.

Impact of statin therapy on all-cause mortality and ICD interventions in heart failure patients - a systematic review

OBJECTIVES

Implantable cardioverter defibrillators (ICDs) have a unique role for the primary and secondary prevention of sudden cardiac death (SCD). The aim of our systematic review is to present the existing data about the impact of statins on all-cause mortality and ICD interventions in heart failure (HF) patients who had an ICD implanted either for primary or for secondary prevention of SCD.

METHODS AND RESULTS

We searched PubMed database and the reference list of the relevant studies for retrieving studies evaluating the effect of statins on all-cause mortality and ICD interventions in HF patients. We finally included 17 relevant studies in our systematic review. Of them, nine studies included data about the impact of statins on all-cause mortality, eight studies about the impact of statins on appropriate ICD interventions and three studies about the impact of statins on inappropriate ICD interventions in HF patients. These data showed that statins seem to have a beneficial role in the reduction of all-cause mortality and ICD interventions in HF patients.

CONCLUSIONS

Statins seem to have a beneficial role in the reduction of all-cause mortality and ICD interventions in HF patients. However, further research about pleiotropic effects of statins is needed as well randomized control trials to elucidate the exact role of statin therapy in ICD outcomes.

Adjuvant antiarrhythmic therapy in patients with implantable cardioverter defibrillators

The risk of sudden cardiac death from ventricular fibrillation or ventricular tachycardia in patients with cardiomyopathy related to structural heart disease has been favorably impacted by the wide adaptation of implantable cardioverter defibrillators (ICDs) for both primary and secondary prevention. Unfortunately, after ICD implantation both appropriate and inappropriate ICD therapies are common. ICD shocks in particular can have significant effects on quality of life and disease-related morbidity and mortality. While not indicated for primary prevention of ICD therapies, beta-blockers and antiarrhythmic drugs are a cornerstone for secondary prevention of them. This review will summarize our current understanding of adjuvant antiarrhythmic drug therapy in ICD patients. The review will also discuss the roles of nonantiarrhythmic drug approaches that are used in isolation and in combination with antiarrhythmic drugs to reduce subsequent risk of ICD shocks.

Long-term clinical outcomes of statin use for chronic heart failure: a meta-analysis of 15 prospective studies

BACKGROUND

The effect of statin treatment on the long-term prognosis in patients with chronic heart failure (CHF) remains uncertain. This study aimed to answer the question by a meta-analysis.

METHODS

The Cochrane databases, MEDLINE and EMBASE, were systematically searched. The eligibility of prospective studies that assigned CHF patients to receive statin treatment and a control (no statin treatment), had defined prognostic outcomes as primary endpoint, and had a minimal follow-up of 12 months was determined.

RESULTS

Fifteen studies involving 45,110 patients were included in the analysis. Additional statin treatment was associated with reduced all-cause mortality (risk ratios [RR] = 0.71, 95% confidence intervals [CI] 0.61-0.83) and reduced rehospitalisation rate for heart failure (RR = 0.84, 95% CI 0.74-0.96). Statin treatment, however, had little impact on pump failure mortality, cardiovascular mortality, and sudden cardiac death. Atorvastatin treatment appeared to facilitate to reduce all-cause mortality (lnRR = 0.61, p = 0.05) and rehospitalisation for heart failure (lnRR = 0.44, p = 0.04) compared with non-atorvastatin therapy.

CONCLUSIONS

Based on the available data, statins persistently decreased all-cause mortality and the incidence of rehospitalisation for heart failure in CHF patients, and the benefits might be partially associated with use of specific statin.

Statins and the reduction of sudden cardiac death: antiarrhythmic or anti-ischemic effect?

Sudden cardiac death is an important cause of cardiovascular mortality with the majority of cases occurring in low-risk groups. HMG-CoA reductase inhibitors (statins) have recently been shown to reduce the incidence of ventricular tachycardia (VT)/fibrillation (VF) and sudden cardiac death, and this has been attributed to their pleiotropic effects. However, it is unclear whether this occurs through an 'indirect' anti-ischemic or 'direct' antiarrhythmic effect. We systematically reviewed articles published on MEDLINE between January 1996 and December 2009 focusing on the reduction of VT/VF and sudden cardiac death by statins and the potential mechanisms. Studies reporting sudden cardiac death or VT/VF outcomes with statin use (n = 23) or the pathophysiology of sudden cardiac death reduction by statins (n = 19) were included. We found that statins have been shown to reduce VT/VF and sudden cardiac death only in subjects with underlying coronary artery disease or ischemic cardiomyopathy. No definite benefits were seen with statins in sudden cardiac death and VT/VF in patients with non-ischemic cardiomyopathy. There is insufficient evidence to point toward a benefit in populations at low risk for VT/VF. In conclusion, an anti-ischemic rather than a primary antiarrhythmic effect emerges as the likely mechanism of sudden cardiac death reduction with statins.

Impact of lipid-lowering therapy on outcomes in atrial fibrillation

Lipid-lowering therapy (LLT) decreases mortality in select patient populations. LLT has also been shown to have antiarrhythmic effects, thus favorably influencing the incidence and recurrence of atrial fibrillation (AF). However, data are lacking regarding the effect of LLT on mortality in patients with AF. The Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) study was the one of the largest multicenter trials comprising of 4,060 patients with AF at high risk for stroke and death. This is a post hoc analysis of the National Heart, Lung, and Blood Institute limited-access dataset of AFFIRM patients who were on LLT at the time of randomization (n = 913). The control group consisted of AFFIRM patients who were not on LLT (n = 3,147). Cox proportional hazards analysis was performed controlling for baseline differences. The end point was all-cause mortality, cardiovascular mortality, and ischemic stroke. A separate analysis was carried out for the combined end point of death, ventricular tachycardia, ventricular fibrillation, cardiac arrest, ischemic stroke, major bleeding, systemic embolism, pulmonary embolism, and myocardial infarction. Patients on LLT were younger and on more cardioactive medications but also had more cardiovascular morbidities. On multivariate analysis, LLT use was associated with lower all-cause mortality (hazard ratio [HR] 0.77, 95% confidence interval [CI] 0.62 to 0.95, p = 0.01), cardiovascular mortality (HR 0.71, 95% CI 0.53 to 0.95, p = 0.02), ischemic stroke (HR 0.56, 95% CI 0.36 to 0.89, p = 0.01), and combined end point (HR 0.81, 95% CI 0.69 to 0.96, p = 0.01). In conclusion, a decrease in mortality and adverse cardiovascular events was observed using LLT in AF.

Reduction in the intensity rate of appropriate shocks for ventricular arrhythmias with statin therapy

Higher rate of implantable cardioverter-defibrillator (ICD) shocks has been associated with increased mortality and morbidity. The aim of our study was to determine whether statins reduced the intensity rate of appropriate shock therapy for ventricular tachycardia/fibrillation in patients with an ICD placed for left ventricular systolic dysfunction. In this retrospective single center analysis, patients with an ejection fraction <or=35% who underwent ICD implantation were divided into treatment and control groups based on statin use. A zero-inflated negative binomial model was used to compare the intensity rate of appropriate ICD shocks between the 2 groups. Characteristics associated with shock-free follow-up were assessed using a stepwise logistic regression model. We found 699 patients eligible for inclusion, with 412 (59%) in the statin treatment group. The adjusted mean intensity rate of shocks was lower in patients on statin therapy (intensity rate ratio = 0.22; 95% confidence interval, 0.12-0.41; P < 0.001). Statin use was associated with a significantly higher probability of shock-free follow-up (odds ratio = 1.64; 95% confidence interval, 1.09-2.48; P = 0.019). In conclusion, statins reduced the intensity rate of appropriate shock therapy for ventricular tachycardia/fibrillation and increased probability of shock-free follow-up in patients with cardiomyopathy. Larger randomized trials are needed to confirm this relationship.