β-Blockers for the prevention of acute exacerbations of chronic obstructive pulmonary disease (βLOCK COPD): a randomised controlled study protocol

Heart Rate Variability on 10-Second Electrocardiogram and Risk of Acute Exacerbation of COPD: A Secondary Analysis of the BLOCK COPD Trial

Introduction

Autonomic dysfunction is common in chronic obstructive pulmonary disease (COPD), and worse autonomic function may be a marker of risk for acute exacerbations of COPD (AECOPD). Heart rate variability (HRV) is a measure of autonomic function. Our objective was to test whether lower (worse) HRV is a risk factor for AECOPD.

Methods

We measured standard deviation of normal RR intervals (SDNN) and root mean square of successive RR interval differences (RMSSD) on 10-second electrocardiograms (ECGs) performed at screening and day 42 in participants in the Beta Blockers for the Prevention of Acute Exacerbations of COPD trial ( BLOCK-COPD), a placebo-controlled trial of metoprolol for prevention of AECOPD. We used Cox-proportional hazards models to test if these HRV measures were associated with risk of any AECOPD, and separately, hospitalized AECOPD. We tested associations using baseline HRV measures and incorporating HRV measures from day 42 as a time-varying covariate. We also tested for interactions with metoprolol assignment.

Results

Of 532 trial participants, 529 (forced expiratory volume in 1 second [FEV1 ]41 ± 16.3 % predicted) were included in this analysis. We did not find a significant association between HRV measures and risk of AECOPD when all participants were analyzed together. There was a significant interaction between RMSSD and assignment to metoprolol on time to first hospitalized AECOPD; in the placebo group greater RMSSD was associated with a lower risk of hospitalized AECOPD (adjusted hazard ratio0.71, 95% confidence interval: 0.52 to 0.96, per 10 ms increase) but there was no association in the metoprolol group.

Conclusions

Autonomic dysfunction as measured by HRV may be a risk factor for AECOPD. Future studies should analyze longer HRV recordings and their performance in broader samples of people with COPD, including those on beta-blockers.

Chronotropic Index and Acute Exacerbations of Chronic Obstructive Pulmonary Disease: A Secondary Analysis of BLOCK COPD

Rationale: The chronotropic index quantifies the proportion of the expected heart rate increase that is attained during exercise. The relationship between the chronotropic index and acute exacerbations of chronic obstructive pulmonary disease (AECOPDs) has not been evaluated. Objectives: To determine whether a higher chronotropic index during a 6-minute walk (CI-6MW) is associated with lower risk of AECOPD and whether the CI-6MW is a marker of susceptibility to adverse effects of metoprolol in chronic obstructive pulmonary disease (COPD). Methods: We analyzed data from the BLOCK COPD (Beta-Blockers for the Prevention of AECOPDs) trial. We used Cox proportional hazards models to investigate the relationship between the CI-6MW and the time to AECOPDs. We also tested for interactions between study group assignment (metoprolol vs. placebo) and the CI-6MW on the time to AECOPDs. Results: Four hundred seventy-seven participants with exacerbation-prone COPD (mean forced expiratory volume in 1 second, 41% of predicted) were included in this analysis. A higher CI-6MW was independently associated with a decreased risk of AECOPDs of any severity (adjusted hazard ratio per 0.1 increase in CI-6MW of 0.88; 95% confidence interval, 0.80-0.96) but was not independently associated with AECOPDs requiring hospitalization (adjusted hazard ratio, 0.94; 95% confidence interval, 0.81-1.05). There was a significant interaction by treatment assignment, and in a stratified analysis, the protective effects of a higher CI-6MW on AECOPDs were negated by metoprolol use. Conclusions: A higher CI-6MW is associated with a decreased risk of AECOPDs and may be an indicator of susceptibility to the adverse effects of metoprolol.

Beta-blockers in chronic obstructive pulmonary disease: the good, the bad and the ugly

PURPOSE OF REVIEW

Several observational studies have suggested that β-blockers, especially cardioselective ones, are well tolerated and associated with a lower risk of acute exacerbations and death in patients with chronic obstructive pulmonary disease (COPD). However, there are dissenting studies. This review provides an update on the use of β-blockers in COPD, focusing on results of recent prospective studies and randomized controlled trials.

RECENT FINDINGS

In totality, cohort studies indicate that β-blockers are generally well tolerated and effective in COPD patients who also have a clear cardiovascular indication for these medications. Although β-blockers on average reduce lung function acutely in COPD patients, the absolute decrease is relatively small, especially if cardioselective β-blockers are used. The results of two large randomized controlled trials suggest that β-blocker use does not reduce the therapeutic benefits of inhaled bronchodilators in COPD patients. The use of β-blockers in COPD patients, who do not have overt cardiovascular disease, does not prevent COPD exacerbations and may paradoxically increase the risk of COPD-related hospitalization and mortality.

SUMMARY

The use of β-blockers is generally well tolerated and effective in COPD patients, who also have a clear cardiovascular indication for these drugs. However, they should not be used in patients who do not have overt cardiovascular disease as β-blockers can reduce lung function, worsen health status and increase the risk of COPD-related hospitalization.

Beta-blockeRs tO patieNts with CHronIc Obstructive puLmonary diseasE (BRONCHIOLE) - Study protocol from a randomized controlled trial

BACKGROUND

Observational studies indicate that beta-blockers are associated with a reduced risk of exacerbation and mortality in patients with chronic obstructive pulmonary disease (COPD) even without overt cardiovascular disease, but data from randomized controlled trials (RCT) are lacking. The aim of this RCT is to investigate whether beta-blocker therapy in patients with COPD without diagnosed cardiovascular disease is associated with a decreased 1-year risk of the composite endpoint of death, exacerbations, or cardiovascular events.

METHODS

The Beta-blockeRs tO patieNts with CHronIc Obstructive puLmonary diseasE (BRONCHIOLE) study is an open-label, multicentre, prospective RCT. A total of 1700 patients with COPD will be randomly assigned to either standard COPD care and metoprolol at a target dose of 100 mg per day or to standard COPD care only. The primary endpoint is a composite of death, COPD exacerbations, and cardiovascular events. Major exclusion criteria are ischemic heart disease, left-sided heart failure, cerebrovascular disease, critical limb ischemia, and atrial fibrillation/flutter. Study visits are an inclusion visit, a metoprolol titration visit at 1 month, follow-up by telephone at 6 months, and a final study visit after 1 year. Outcome data are obtained from medical history and record review during study visits, as well as from national registries.

DISCUSSION

BRONCHIOLE is a pragmatic randomized trial addressing the potential of beta-blockers in patients with COPD. The trial is expected to provide relevant clinical data on the efficacy of this treatment on patient-related outcomes in patients with COPD.

TRIAL REGISTRATION

ClinicalTrials.gov, ID: NCT03566667. Registered on 25 June 2018.

Chronic Obstructive Pulmonary Disease and Heart Failure: A Breathless Conspiracy

Heart failure (HF) and chronic obstructive pulmonary disease (COPD) are both common causes of breathlessness and often conspire to confound accurate diagnosis and optimal therapy. Risk factors (such as aging, smoking, and obesity) and clinical presentation (eg, cough and breathlessness on exertion) can be very similar, but the treatment and prognostic implications are very different. This review discusses the diagnostic challenges in individuals with exertional dyspnea. Also highlighted are the prevalence, clinical relevance, and therapeutic implications of a concurrent diagnosis of COPD and HF.

Metoprolol for the Prevention of Acute Exacerbations of COPD

BACKGROUND

Observational studies suggest that beta-blockers may reduce the risk of exacerbations and death in patients with moderate or severe chronic obstructive pulmonary disease (COPD), but these findings have not been confirmed in randomized trials.

METHODS

In this prospective, randomized trial, we assigned patients between the ages of 40 and 85 years who had COPD to receive either a beta-blocker (extended-release metoprolol) or placebo. All the patients had a clinical history of COPD, along with moderate airflow limitation and an increased risk of exacerbations, as evidenced by a history of exacerbations during the previous year or the prescribed use of supplemental oxygen. We excluded patients who were already taking a beta-blocker or who had an established indication for the use of such drugs. The primary end point was the time until the first exacerbation of COPD during the treatment period, which ranged from 336 to 350 days, depending on the adjusted dose of metoprolol.

RESULTS

A total of 532 patients underwent randomization. The mean (±SD) age of the patients was 65.0±7.8 years; the mean forced expiratory volume in 1 second (FEV1) was 41.1±16.3% of the predicted value. The trial was stopped early because of futility with respect to the primary end point and safety concerns. There was no significant between-group difference in the median time until the first exacerbation, which was 202 days in the metoprolol group and 222 days in the placebo group (hazard ratio for metoprolol vs. placebo, 1.05; 95% confidence interval [CI], 0.84 to 1.32; P = 0.66). Metoprolol was associated with a higher risk of exacerbation leading to hospitalization (hazard ratio, 1.91; 95% CI, 1.29 to 2.83). The frequency of side effects that were possibly related to metoprolol was similar in the two groups, as was the overall rate of nonrespiratory serious adverse events. During the treatment period, there were 11 deaths in the metoprolol group and 5 in the placebo group.

CONCLUSIONS

Among patients with moderate or severe COPD who did not have an established indication for beta-blocker use, the time until the first COPD exacerbation was similar in the metoprolol group and the placebo group. Hospitalization for exacerbation was more common among the patients treated with metoprolol. (Funded by the Department of Defense; BLOCK COPD ClinicalTrials.gov number, NCT02587351.).

Beta-Blockers in COPD: A Methodological Review of the Observational Studies

The use of beta-blockers in patients with chronic obstructive pulmonary disease (COPD) has received much attention. Several observational studies reported important reductions in mortality and exacerbations with these drugs, but the extent of bias in these studies is unclear. Nevertheless, the large ongoing randomized trial (βLOCK-COPD) was initiated specifically to evaluate these effects. We searched the literature to identify all observational studies investigating the effectiveness of beta-blockers in COPD patients on major outcomes, including death and COPD exacerbation. We identified 18 observational studies, with 10 studies affected by confounding bias and six by immortal time bias, while two addressed these biases. Reductions in all-cause mortality with beta-blocker use were observed among the studies with confounding bias (pooled rate ratio 0.72; 95% CI 0.59-0.88) and those with immortal time bias (pooled rate ratio 0.64; 95% CI 0.53-0.77). A large five-database study that addressed these two biases reported hazard ratios of 0.90 (95% CI: 0.78-1.02) for death and 0.54 (95% CI: 0.47-0.61) for COPD hospitalization. However, this latter estimate was the same as for the first 30 days after treatment initiation, thus indicating that important residual confounding cannot be ruled out. Observational studies, important to provide evidence from real-world data on medication effects, are unsupportive for beta-blockers in COPD. Even if immortal time bias is properly avoided, confounding bias cannot be fully controlled due to their relative contraindication in COPD. In the case of beta-blockers, randomized trials such as βLOCK-COPD are necessary to eliminate the uncertainty from residual confounding bias.

β-Blockers and the Rate of Chronic Obstructive Pulmonary Disease Exacerbations

Objective: To review the rate of exacerbations relative to β-blocker use in patients with chronic obstructive pulmonary disease (COPD). Data Sources: A MEDLINE search (1953 to May 2019) was performed using the search terms beta-blockers, chronic obstructive pulmonary disease, and exacerbations. An EMBASE search was also performed using the search terms chronic obstructive lung disease and beta adrenergic receptor blocking agents (1970 to May 2019). References from the review of literature citations were also identified. Study Selection and Data Extraction: English-language studies assessing COPD exacerbations in patients prescribed a β-blocker were included. Any article not addressing exacerbations was excluded. Data Synthesis: A total of 15 articles were included; 7 articles showed no change, 1 provided mixed results, and 7 indicated a significant decrease in COPD exacerbations in a variety of exacerbation severities. Two of the studies differentiated between cardioselective and noncardioselective β-blockers. Relevance to Patient Care and Clinical Practice: This work represents an initial assessment of the use of β-blockers to reduce COPD exacerbations. The findings raise the question if β-blockers should be used more frequently in patients with COPD. Conclusions: Based on the limited number of studies that address β-blocker use in COPD, it appears that exacerbations are not increased and may be decreased. A randomized, placebo-controlled trial is in progress to possibly provide more definitive answers to this question. Until the trial is complete, β-blockers should not be withheld in COPD patients who have concurrent cardiovascular conditions, especially where there is a mortality benefit.

Mortality associated with cardiovascular drugs in patients with chronic obstructive pulmonary disease and right-sided heart failure - A danish nationwide registry-based study

BACKGROUND

The optimal medical treatment in patients with chronic obstructive pulmonary disease (COPD) and right-sided heart failure (RHF) is unknown. We aimed to estimate the risks of all-cause mortality associated with the current clinical use of various cardiovascular drugs in this patient-group.

METHODS

We followed all patients with registered COPD and RHF (defined as a diagnosis of pulmonary hypertension plus use of loop-diuretics) for the risk of all-cause mortality (Jan 1, 1995 to Dec 31, 2015) using the Danish nationwide administrative registries. The association between mortality and claimed prescriptions for cardiovascular drugs was assessed by multivariable Cox regression models.

RESULTS

5991 patients (mean age 74 ± standard deviation 10 years, 51% women) were included. Of these, 1440 (24%) used beta-blockers, 2149 (36%) renin-angiotensin system inhibitors [RASi], 1340 (22%) oral anticoagulants, 1376 (23%) calcium channel blockers, 1194 (20%) statins, 1824 (30%) spironolactone, and 2099 (35%) low-dose aspirin. During an average follow-up of 2.2 years (±standard deviation 2.8, min-max 0-19.6 years), 5071 (85%) died, corresponding to a mortality rate of 38 per 100 person-years (95% confidence interval 37-39). Compared to no use, beta-blockers were associated with adjusted hazards ratio 0.90 (95% confidence interval 0.84-0.98), RASi 0.92 (0.86-0.98), calcium channel blockers 0.86 (0.80-0.92), spironolactone 1.17 (1.10-1.24), statins 0.85 (0.78-0.92), oral anticoagulants 0.87 (0.79-0.95), and aspirin 0.99 (0.93-1.05). Propensity-score matched analyses and inverse-probability-weighted models yielded similar results.

CONCLUSION

Several cardiovascular drugs may be associated with lowered mortality in COPD and RHF. Given the grave prognosis, randomized clinical trials are warranted to test this hypothesis.

Impact of pulmonary emphysema on exercise capacity and its physiological determinants in chronic obstructive pulmonary disease

Exercise limitation is common in chronic obstructive pulmonary disease (COPD). We determined the impact of pulmonary emphysema on the physiological response to exercise independent of contemporary measures of COPD severity. Smokers 40–79 years old with COPD underwent computed tomography, pulmonary function tesing, and symptom-limited incremental exercise testing. COPD severity was quantified according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) by spirometry (GOLD 1–4); and symptom burden and exacerbation risk (GOLD A-D). Emphysema severity was quantified as the percent lung volume <−950 Hounsfield units. Regression models adjusted for age, gender, body size, smoking status, airflow limitation, symptom burden and exacerbation risk. Among 67 COPD subjects (age 67 ± 8 years; 75% male; GOLD 1–4: 11%, 43%, 30%, 16%), median percent emphysema was 11%, and peak power output (PPO) was 61 ± 32 W. Higher percent emphysema independently predicted lower PPO (−24 W per 10% increment in emphysema; 95%CI −41 to −7 W). Throughout exercise, higher percent emphysema predicted 1) higher minute ventilation, ventilatory equivalent for CO₂, and heart rate; and 2) lower oxy-hemoglobin saturation, and end-tidal PCO₂. Independent of contemporary measures of COPD severity, the extent of pulmonary emphysema predicts lower exercise capacity, ventilatory inefficiency, impaired gas-exchange and increased heart rate response to exercise.

Beta-blocker under-use in COPD patients

Background

Cardiovascular (CVS) comorbidities are common in COPD and contribute significantly to morbidity and mortality, especially following acute exacerbations of COPD (AECOPD). Beta-blockers (BBs) are safe and effective in COPD patients, with demonstrated survival benefit following myocardial infarction. We sought to determine if BBs are under-prescribed in patients hospitalized with AECOPD. We also sought to determine inpatient rates of CVS and cerebrovascular complications, and their impact on patient outcomes.

Methods

Retrospective hospital data was collected over a 12-month period. The medical records of all patients >40 years of age coded with a diagnosis of AECOPD were analyzed. Prevalent use and incident initiation of BBs were assessed. Comorbidities including indications and contraindications for BB use were analyzed.

Results

Of the 366 eligible patients, 156 patients (42.6%) had at least one indication for BB use – of these patients, only 53 (34.0%) were on BB therapy and 61 (39.1%) were not on BB therapy but had no listed contraindication. Prevalent use of BBs at the time of admission in all 366 patients was 19.7%, compared with 45.6%, 39.6% and 45.9% use of anti-platelets, statins and angiotensin-converting enzyme inhibitor/angiotensin II receptor blockers, respectively. CVS and cerebrovascular complications were common in this population (57 patients, 16%) and were associated with longer length of stay (p<0.01) and greater inpatient mortality (p=0.02).

Conclusions

BBs are under-prescribed in COPD patients despite clear indication(s) for their use. Further work is required to explore barriers to BB prescribing in COPD patients.

Effectiveness and safety of concurrent beta-blockers and inhaled bronchodilators in COPD with cardiovascular comorbidities

Chronic obstructive pulmonary disease (COPD) is the most common chronic respiratory disease and its prevalence is increasing worldwide, in both industrialised and developing countries. Its prevalence is ∼5% in the general population and it is the fourth leading cause of death worldwide. COPD is strongly associated with cardiovascular diseases; in fact, ∼64% of people suffering from COPD are treated for a concomitant cardiovascular disease and approximately one in three COPD patients die as a consequence of cardiovascular diseases.Inhaled bronchodilators might have adverse cardiovascular effects, including ischaemic events and arrhythmias, and beta-blockers might adversely influence the respiratory symptoms and the response to bronchodilators. For these reasons, it is important to know the safety profiles and the possible interactions between these two classes of drug, in order to prescribe them with greater awareness.In this article, we review the literature about the epidemiology of COPD, its association with cardiovascular diseases, and the safety of concurrent use of inhaled bronchodilators and beta-blockers, as a tool for improving the approach to complex therapies in clinical practice.

Bringing Stability to the Chronic Obstructive Pulmonary Disease Patient: Clinical and Pharmacological Considerations for Frequent Exacerbators

Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are critical events associated with an accelerated loss of lung function, increased morbidity, and excess mortality. AECOPD are heterogeneous in nature and this may directly impact clinical decision making, specifically in patients with frequent exacerbations. A 'frequent exacerbator' is a sub-phenotype of chronic obstructive pulmonary disease (COPD) and is defined as an individual who experiences two or more moderate-to-severe exacerbations per year. This distinct subgroup has higher mortality and accounts for more than half of COPD-related hospitalizations annually. Thus, it is imperative to identify individuals at risk for frequent exacerbations and choose optimal strategies to minimize risk for these events. New paradigms for using combination inhalers and the introduction of novel oral compounds provide expanded treatment options to reduce the risk and frequency of exacerbations. The goals of managing frequent exacerbators or patients at risk for AECOPD are: (1) maximizing bronchodilation; (2) reducing inflammation; and (3) targeting specific molecular pathways implicated in COPD and AECOPD pathogenesis. Novel inhaler therapies including combination long-acting muscarinic agents plus long-acting beta agonists show promising results compared with monotherapy or a long-acting beta agonist inhaled corticosteroid combination in reducing exacerbation risk among individuals at risk for exacerbations and among frequent exacerbators. Likewise, oral medications including macrolides and phosphodiesterase-4 inhibitors reduce the risk for AECOPD in select groups of individuals at high risk for exacerbation. Future direction in COPD management is based on the identification of various subtypes or 'endotypes' and targeting therapies based on their pathophysiology. This review describes the impact of AECOPD and the challenges posed by frequent exacerbators, and explores the rationale for different pharmacologic approaches to preventing AECOPD in these individuals.

Evidence of potential bias in a comparison of β blockers and calcium channel blockers in patients with chronic obstructive pulmonary disease and acute coronary syndrome: results of a multinational study

OBJECTIVES

A number of observational studies have reported that, in patients with chronic obstructive pulmonary disease (COPD), β blockers (BBs) decrease risk of mortality and COPD exacerbations. To address important methodological concerns of these studies, we compared the effectiveness and safety of cardioselective BBs versus non-dihydropyridine calcium channel blockers (non-DHP CCBs) in patients with COPD and acute coronary syndromes (ACS) using a propensity score (PS)-matched, active comparator, new user design. We also assessed for potential unmeasured confounding by examining a short-term COPD hospitalisation outcome.

SETTING AND PARTICIPANTS

We identified 22 985 patients with COPD and ACS starting cardioselective BBs or non-DHP CCBs across 5 claims databases from the USA, Italy and Taiwan.

PRIMARY AND SECONDARY OUTCOME MEASURES

Stratified Cox regression models were used to estimate HRs for mortality, cardiovascular (CV) hospitalisations and COPD hospitalisations in each database after variable-ratio PS matching. Results were combined with random-effects meta-analyses.

RESULTS

Cardioselective BBs were not associated with reduced risk of mortality (HR, 0.90; 95% CI 0.78 to 1.02) or CV hospitalisations (HR, 1.06; 95% CI 0.91 to 1.23), although statistical heterogeneity was observed across databases. In contrast, a consistent, inverse association for COPD hospitalisations was identified across databases (HR, 0.54; 95% CI 0.47 to 0.61), which persisted even within the first 30 days of follow-up (HR, 0.55; 95% CI 0.37 to 0.82). Results were similar across a variety of sensitivity analyses, including PS trimming, high dimensional-PS matching and restricting to high-risk patients.

CONCLUSIONS

This multinational study found a large inverse association between cardioselective BBs and short-term COPD hospitalisations. The persistence of this bias despite state-of-the-art pharmacoepidemiologic methods calls into question the ability of claims data to address confounding in studies of BBs in patients with COPD.

Effectiveness of diagnostic screening tests in mass screening for COPD using a cooperative regional system in a region with heavy air pollution: a cross-sectional study

OBJECTIVES

This study aimed to evaluate the effectiveness of a cooperative healthcare model for early detection and diagnosis of chronic obstructive pulmonary disease (COPD).

METHODS

This was a cross-sectional observational study. We performed diagnosis of COPD at 4 public health centres in Ōmuta, Japan from March 2015 to March 2016, by adding screening for COPD at the time of routine medical evaluations. All patients aged over 40 years were eligible to participate. Among 397 eligible patients, 293 agreed to participate in the study.

RESULTS

The estimated prevalence of COPD in Ōmuta was 10% among patients aged over 40 years and was 17% among smokers. Among those who were screened, over half of them had questionnaire scores over the cut-off of 17 points and decreased FEV1/FVC%, indicating COPD (p>0.05). 30 patients with suspected COPD were referred for further investigation at a local central hospital, but only 6 underwent further medical examinations.

CONCLUSIONS

The combination of a COPD questionnaire and medical examination is effective as a COPD screening tool. Future research should investigate behavioural interventions for smoking cessation that can be offered in a cooperative model, as well as for improving participation in COPD screening and for encouraging early presentation for treatment in those suspected of having COPD.

β-Blockers, heart disease and COPD: current controversies and uncertainties

Treating people with cardiovascular disease and COPD causes significant clinician anxiety. β-Blockers save lives in people with heart disease, specifically postinfarction and heart failure. COPD and heart disease frequently coexist and people with both disorders have particularly high cardiovascular mortality. There are concerns about giving β-blockers to people with concomitant COPD that include reduced basal lung function, diminished effectiveness of emergency β-agonist treatments, reduced benefit of long-acting β-agonist treatment and difficulty in discriminating between asthma and COPD. β-Blockers appear to reduce lung function in both the general population and those with COPD because they are poorly selective for cardiac β1-adrenoceptors over respiratory β2-adrenoceptors, and studies have shown that higher β-agonist doses are required to overcome the β-blockade. COPD and cardiovascular disease share similar environmental risks and both disease states have high adrenergic and inflammatory activation. β-Blockers may therefore be particularly helpful in reducing cardiovascular events in this high-risk group. They may reduce the background inflammatory state, and inhibit the tachycardia and hypertension associated with both the endogenous adrenaline and high-dose β-agonist treatment associated with acute exacerbations of COPD. Some studies have suggested no increased and, at times, reduced mortality in patients with COPD taking β-blockers for heart disease. However, these are all observational studies and there are no randomised controlled trials. Potential ways to improve this dilemma include the development of highly β1-selective β-blockers or the use of non-β-blocking heart rate reducing agents, such as ivabridine, if these are proven to be beneficial in randomised controlled trials.