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

Effectiveness of Aspirin on Major COPD Outcomes: A Prevalent New-User Design Observational Study

Observational studies that have reported an association between aspirin use in chronic obstructive pulmonary disease (COPD) with reductions in mortality and COPD exacerbations were shown to be affected by time-related biases. We assessed this association using a prevalent new-user study design that avoids these biases. We used the United Kingdom's Clinical Practice Research Datalink (CPRD) to form a cohort of patients with COPD. Aspirin initiators were matched on time and propensity score with nonusers during 2002-2018. The outcomes were all-cause mortality and COPD exacerbation within a one-year follow-up. Hazard ratios (HR) and 95% confidence interval (CI) of each outcome associated with aspirin use compared to nonuse were estimated using an as-treated approach. The study cohort included 10,287 initiators of aspirin and 10,287 matched nonusers. The cumulative incidence of all-cause mortality at one year was 11.5% for aspirin users and 9.2% for nonusers. The HR of all-cause mortality associated with aspirin initiation was 1.22 (95% CI: 1.08-1.37), while for severe exacerbation it was 1.21 (95% CI 1.08-1.37), compared with nonuse. The HR of a first moderate or severe exacerbation with aspirin use was 0.90 (95% CI 0.85-0.95). These estimates did not vary by platelet count. This large population-based study, designed to emulate a trial, found aspirin use in patients with COPD associated with a higher risk of all-cause mortality and severe exacerbation, but a lower risk of moderate or severe exacerbation. Further research is warranted to assess this reduction in moderate or severe exacerbations, particularly in patients with cardiovascular risk factors.

β-Blocker Use and Clinical Outcomes in Patients With COPD Following Acute Myocardial Infarction

Importance

While β-blockers are associated with decreased mortality in cardiovascular disease (CVD), exacerbation-prone patients with chronic obstructive pulmonary disease (COPD) who received metoprolol in the Beta-Blockers for the Prevention of Acute Exacerbations of Chronic Obstructive Pulmonary Disease (BLOCK-COPD) trial experienced increased risk of exacerbations requiring hospitalization. However, the study excluded individuals with established indications for the drug, raising questions about the overall risk and benefit in patients with COPD following acute myocardial infarction (AMI).

Objective

To investigate whether β-blocker prescription at hospital discharge is associated with increased risk of mortality or adverse cardiopulmonary outcomes in patients with COPD and AMI.

Design, Setting, and Participants

This prospective, longitudinal cohort study with 6 months of follow-up enrolled patients aged 35 years or older with COPD who underwent cardiac catheterization for AMI at 18 BLOCK-COPD network hospitals in the US from June 2020 through May 2022.

Exposure

Prescription for any β-blocker at hospital discharge.

Main Outcomes and Measures

The primary outcome was time to the composite outcome of death or all-cause hospitalization or revascularization. Secondary outcomes included death, hospitalization, or revascularization for CVD events, death or hospitalization for COPD or respiratory events, and treatment for COPD exacerbations.

Results

Among 3531 patients who underwent cardiac catheterization for AMI, prevalence of COPD was 17.1% (95% CI, 15.8%-18.4%). Of 579 total patients with COPD and AMI, 502 (86.7%) were prescribed a β-blocker at discharge. Among the 562 patients with COPD included in the final analysis, median age was 70.0 years (range, 38.0-94.0 years) and 329 (58.5%) were male; 553 of the 579 patients (95.5%) had follow-up information. Among those discharged with β-blockers, there was no increased risk of the primary end point of all-cause mortality, revascularization, or hospitalization (hazard ratio [HR], 1.01; 95% CI, 0.66-1.54; P = .96) or of cardiovascular events (HR, 1.11; 95% CI, 0.65-1.92; P = .69), COPD-related or respiratory events (HR, 0.75; 95% CI, 0.34-1.66; P = .48), or treatment for COPD exacerbations (rate ratio, 1.01; 95% CI, 0.53-1.91; P = .98).

Conclusions and Relevance

In this cohort study, β-blocker prescription at hospital discharge was not associated with increased risk of adverse outcomes in patients with COPD and AMI. These findings support use of β-blockers in patients with COPD and recent AMI.

The influence of immortal time bias in observational studies examining associations of antifibrotic therapy with survival in idiopathic pulmonary fibrosis: A simulation study

Background

Immortal time bias (ITB) has been overlooked in idiopathic pulmonary fibrosis (IPF). We aimed to identify the presence of ITB in observational studies examining associations between antifibrotic therapy and survival in patients with IPF and illustrate how ITB may affect effect size estimates of those associations.

Methods

Immortal time bias was identified in observational studies using the ITB Study Assessment Checklist. We used a simulation study to illustrate how ITB may affect effect size estimates of antifibrotic therapy on survival in patients with IPF based on four statistical techniques including time-fixed, exclusion, time-dependent and landmark methods.

Results

Of the 16 included IPF studies, ITB was detected in 14 studies, while there were insufficient data for assessment in two others. Our simulation study showed that use of time-fixed [hazard ratio (HR) 0.55, 95% confidence interval (CI) 0.47-0.64] and exclusion methods (HR 0.79, 95% CI 0.67-0.92) overestimated the effectiveness of antifibrotic therapy on survival in simulated subjects with IPF, in comparison of the time-dependent method (HR 0.93, 95% CI 0.79-1.09). The influence of ITB was mitigated using the 1 year landmark method (HR 0.69, 95% CI 0.58-0.81), compared to the time-fixed method.

Conclusion

The effectiveness of antifibrotic therapy on survival in IPF can be overestimated in observational studies, if ITB is mishandled. This study adds to the evidence for addressing the influence of ITB in IPF and provides several recommendations to minimize ITB. Identifying the presence of ITB should be routinely considered in future IPF studies, with the time-dependent method being an optimal approach to minimize ITB.

Beta-blocker use in patients with chronic obstructive pulmonary disease: A systematic review: A systematic review of βB in COPD

Beta-blockers (βB) are a frequently used class of medications. Although βB have many indications, those related to cardiovascular disease are among the most common and important. However, in patients with chronic obstructive pulmonary disease (COPD), βB are used less often due to concerns about an unfavorable impact on respiratory morbidity and mortality. We performed a systematic review to assess the safety of βB in patients with COPD. We included a total of 2 randomized controlled trials and 28 observational studies. The majority found statistically significant reductions in mortality. The two higher quality observational studies reported increased mortality with βB. The risk of COPD exacerbations was reduced in about half of the studies. Nonetheless, there were significant biases that confounded the results. The highest quality RCT found a significant increase in severe and very severe COPD exacerbations with βB use. In conclusion, data on the safety of βB in patients with COPD are conflicting. However, given higher quality evidence showed harm with their use, βB should be prescribed with caution in patients with COPD, including patients with cardiac indication for βB.

Preventing adverse cardiac events (PACE) in chronic obstructive pulmonary disease (COPD): study protocol for a double-blind, placebo controlled, randomised controlled trial of bisoprolol in COPD

INTRODUCTION

Heart disease in chronic obstructive pulmonary disease (COPD) is a common but neglected comorbidity. Patients with COPD are frequently excluded from clinical trials of treatments aimed at reducing cardiac morbidity and mortality, which has led to undertreatment of cardiovascular disease in patients with COPD. A particular concern in COPD is the underuse of beta (β)-blockers. There is observational evidence that cardioselective β-blockers are safe and may even reduce mortality risk in COPD, although some evidence is conflicting. There is an urgent need to answer the research question: Are cardioselective β-blockers safe and of benefit in people with moderately severe COPD? The proposed study will investigate whether cardioselective β-blocker treatment in patients with COPD reduces mortality and cardiac and respiratory morbidity.

METHODS AND ANALYSES

This is a double-blind, randomised controlled trial to be conducted in approximately 26 sites in Australia, New Zealand, India, Sri Lanka and other countries as required. Participants with COPD will be randomised to either bisoprolol once daily (range 1.25-5 mg, dependent on tolerated dose) or matched placebo, in addition to receiving usual care for their COPD over the study duration of 24 months.The study will enrol 1164 participants with moderate to severe COPD, aged 40-85 years. Participants will be symptomatic from their COPD and have a postbronchodilator forced expiratory volume in 1 s (FEV₁) ≥30% and ≤70% predicted and a history of at least one exacerbation requiring systemic corticosteroids, antibiotics or both in the prior 24 months.

ETHICS AND DISSEMINATION

The study protocol has been approved by the Sydney Local Health District Human Research Ethics Committee at The Concord Repatriation General Hospital.

TRIAL REGISTRATION NUMBERS

NCT03917914; CTRI/2020/08/027322.

Effectiveness of Aspirin in COPD: Biases in the Observational Studies

Several observational studies report decreased incidence of mortality and of exacerbations with aspirin use in patients with chronic obstructive pulmonary disease (COPD), with calls for a large randomized trial. Aspirin does have local and systemic pulmonary mechanisms of action that could make this drug beneficial in the treatment of COPD. However, the potential for biases in the observational studies has not been examined. We searched the literature for all observational studies reporting on the effect of aspirin in COPD patients on exacerbation and mortality. We reviewed the studies for the presence of time-related and other biases. We identified eight observational studies reporting an overall reduction in all-cause mortality or exacerbation with aspirin use of 21% (pooled rate ratio (RR) 0.79; 95% CI 0.71-0.86). We found two studies affected by immortal time bias (pooled RR 0.81; 95% CI 0.74-0.89), three studies affected by collider-stratification bias (pooled RR 0.66; 95% CI 0.55-0.79) and three that involved some exposure misclassification (pooled RR 0.85; 95% CI 0.78-0.92). Moreover, while adjusting for cardiovascular factors, six of the eight studies did not adjust for important markers of COPD severity and thus remain susceptible to confounding bias. In conclusion, all observational studies reporting on the effectiveness of aspirin on major outcomes of COPD are affected by biases known to exaggerate the effectiveness of a drug. As these studies cannot be used to support a beneficial effect for aspirin in COPD, it would be premature to consider a randomized trial to investigate this question until methodologically rigorous studies are available.

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.

Recent advances on animal models related to chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) has become an important public health problem in the world. According to reports, COPD ranks fourth in the global cause of death, causing a serious economic burden on society. The pathogenesis of COPD is complex, making it difficult to simulate the pathological changes and clinical features of COPD. Moreover, the COPD animal model has an irreplaceable role in the study of etiology, pathology and treatment. It is worth noting that the risk factors for chronic obstructive pulmonary disease persist, and the economic burden of global chronic obstructive pulmonary disease is expected to continue to increase in the coming decades. Establishing a standardized, a clinically realistic COPD animal model has always been a research direction that scholars are keen on. Therefore, it is essential to establish an economical animal model. The establishment of a suitable animal model can accurately simulate the pathological features of human chronic obstructive pulmonary disease and help to develop effective interventions and treatments in a short period of time. This review integrates the experimental animal species selected in the animal models used in COPD studies. Subsequently, different methods and mechanisms for establishing animal models were summarized according to different modeling factors. Finally, the criteria for evaluating existing animal models are discussed. It is hoped that the summary of this paper will guide the establishment of relevant animal models for future COPD research.

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.).

Prevalence of cardiac comorbidities, and their underdetection and contribution to exertional symptoms in COPD: results from the COSYCONET cohort

Background

A substantial prevalence of cardiovascular disease is known for COPD, but detection of its presence, relationship to functional findings and contribution to symptoms remains challenging. The present analysis focusses on the cardiovascular contribution to COPD symptoms and their relationship to the patients’ diagnostic status, medication and echocardiographic findings.

Methods

Patients from the COPD cohort COSYCONET with data on lung function, including FEV₁, residual volume/total lung capacity (RV/TLC) ratio, diffusing capacity TLCO, and echocardiographic data on left ventricular ejection fraction (LVEF) and end-diastolic diameter (LVEDD), medical history, medication, modified British Medical Research Council dyspnea scale (mMRC) and Saint Georges Respiratory Questionnaire (SGRQ) were analyzed.

Results

A total of 1591 patients (GOLD 0–4: n=230/126/614/498/123) fulfilled the inclusion criteria. Ischemic heart disease, myocardial infarction or heart failure were reported in 289 patients (18.2%); 860 patients (54%) received at least one cardiovascular medication, with more than one in many patients. LVEF<50% or LVEDD>56 mm was found in 204 patients (12.8%), of whom 74 (36.3%) had neither a cardiovascular history nor medication. Among 948 patients (59.6%) without isolated hypertension, there were 21/55 (38.2%) patients with LVEF<50% and 47/88 (53.4%) with LVEDD>56 mm, who lacked both a cardiac diagnosis and medication. LVEDD and LVEF were linked to medical history; LVEDD was dependent on RV/TLC and LVEF on FEV₁. Exertional COPD symptoms were best described by mMRC and the SGRQ activity score. Beyond lung function, an independent link from LVEDD on symptoms was revealed.

Conclusion

A remarkable proportion of patients with suspicious echocardiographic findings were undiagnosed and untreated, implying an increased risk for an unfavorable prognosis. Cardiac size and function were dependent on lung function and only partially linked to cardiovascular history. Although the contribution of LV size to COPD symptoms was small compared to lung function, it was detectable irrespective of all other influencing factors. However, only the mMRC and SGRQ activity component were found to be suitable for this purpose.

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.