Lung hyperinflation and functional exercise capacity in patients with COPD - a three-year longitudinal study

The contribution of estimated dead space fraction to mortality prediction in patients with chronic obstructive pulmonary disease-a new proposal

Background

Mortality due to chronic obstructive pulmonary disease (COPD) is increasing. However, dead space fractions at rest (VD/VTrest) and peak exercise (VD/VTpeak) and variables affecting survival have not been evaluated. This study aimed to investigate these issues.

Methods

This retrospective observational cohort study was conducted from 2010-2020. Patients with COPD who smoked, met the Global Initiatives for Chronic Lung Diseases (GOLD) criteria, had available demographic, complete lung function test (CLFT), medication, acute exacerbation of COPD (AECOPD), Charlson Comorbidity Index, and survival data were enrolled. VD/VTrest and VD/VTpeak were estimated (estVD/VTrest and estVD/VTpeak). Univariate and multivariable Cox regression with stepwise variable selection were performed to estimate hazard ratios of all-cause mortality.

Results

Overall, 14,910 patients with COPD were obtained from the hospital database, and 456 were analyzed after excluding those without CLFT or meeting the lung function criteria during the follow-up period (median (IQR) 597 (331-934.5) days). Of the 456 subjects, 81% had GOLD stages 2 and 3, highly elevated dead space fractions, mild air-trapping and diffusion impairment. The hospitalized AECOPD rate was 0.60 ± 2.84/person/year. Forty-eight subjects (10.5%) died, including 30 with advanced cancer. The incidence density of death was 6.03 per 100 person-years. The crude risk factors for mortality were elevated estVD/VTrest, estVD/VTpeak, ≥2 hospitalizations for AECOPD, advanced age, body mass index (BMI) <18.5 kg/m2, and cancer (hazard ratios (95% C.I.) from 1.03 [1.00-1.06] to 5.45 [3.04-9.79]). The protective factors were high peak expiratory flow%, adjusted diffusing capacity%, alveolar volume%, and BMI 24-26.9 kg/m2. In stepwise Cox regression analysis, after adjusting for all selected factors except cancer, estVD/VTrest and BMI <18.5 kg/m2 were risk factors, whereas BMI 24-26.9 kg/m2 was protective. Cancer was the main cause of all-cause mortality in this study; however, estVD/VTrest and BMI were independent prognostic factors for COPD after excluding cancer.

Conclusions

The predictive formula for dead space fraction enables the estimation of VD/VTrest, and the mortality probability formula facilitates the estimation of COPD mortality. However, the clinical implications should be approached with caution until these formulas have been validated.

Association between the Static and Dynamic Lung Function and CT-Derived Thoracic Skeletal Muscle Measurements-A Retrospective Analysis of a 12-Month Observational Follow-Up Pilot Study

BACKGROUND

Patients with chronic obstructive pulmonary disease (COPD) with low skeletal muscle mass and severe airway obstruction have higher mortality risks. However, the relationship between dynamic/static lung function (LF) and thoracic skeletal muscle measurements (SMM) remains unclear. This study explored patient characteristics (weight, BMI, exacerbations, dynamic/static LF, sex differences in LF and SMM, and the link between LF and SMM changes.

METHODS

A retrospective analysis of a 12-month prospective follow-up study patients with stable COPD undergoing standardized treatment, covering mild to severe stages, was conducted. The baseline and follow-up assessments included computed tomography and body plethysmography.

RESULTS

This study included 35 patients (17 females and 18 males). This study revealed that females had more stable LF but tended to have greater declines in SMM areas and indices than males (-5.4% vs. -1.9%, respectively), despite the fact that females were younger and had higher LF and less exacerbation than males. A multivariate linear regression showed a negative association between the inspiratory capacity/total lung capacity ratio (IC/TLC) and muscle fat area.

CONCLUSIONS

The findings suggest distinct LF and BC progression patterns between male and female patients with COPD. A low IC/TLC ratio may predict increased muscle fat. Further studies are necessary to understand these relationships better.

Can static hyperinflation predict exercise capacity in COPD?

INTRODUCTION

The diagnosis and severity assessment of COPD relies on spirometry, and in particular the FEV1. However, it has been proposed that hyperinflation and air-trapping are better predictors of exercise capacity and mortality than the FEV1.

RESEARCH

QUESTION: Does static hyperinflation predict exercise capacity?

METHODS

We conducted an observational prospective study. Patients with COPD referred to the lung function laboratory were consecutively recruited. Patients with hyperinflation (the experimental group) were compared to patients without hyperinflation (the control group). The sample sizes were determined assuming an effect size of 0.5 and a power of 0.80.

RESULTS

We recruited 124 participants, of whom 87% were male, the mean age was 66.1 ± 8.8 years. 67% were symptomatic (GOLD B or D). Airflow limitation was moderate to severe in the majority of patients (median FEV1 47%, IQR 38-65%) and 43% of patients had static hyperinflation. The median 6MWD was 479 meters (404-510) and peak workload in CPET was 64 watts (46-88) with peak VO2 1.12 L/min, 0.89-1.31 L/min. Patients with lower FEV1, DLCO and IC/TLC and higher RV/TLC had reduced exercise capacity in both 6MWT and CPET, measured as lower distance, greater desaturation and ∆Borg dyspnoea, and reduced workload, peak VO2 and peak VE and higher desaturation and ventilatory limitation (VE/MVV). An IC/TLC < 0.33 predicted reduced exercise performance (peak O2 <60%). Dyspnoea assessed by mMRC and QoL measured by CAT and CCQ were also worse in the hyperinflation in COPD patients.

CONCLUSION

In COPD patients, IC/TLC and RV/TLC are valuable predictors of exercise performance in both 6MWT and CPET and PRO.

Validation of Simple Prediction Equations for Step Count in Japanese Patients with Chronic Obstructive Pulmonary Disease

Physical activity is decreased in patients with chronic obstructive pulmonary disease, and decreased physical activity leads to a poor prognosis. To determine an individual’s target step count from the measured step counts and predicted step counts, simple and detailed prediction equations for step count were developed. To verify the validity of the simple prediction equation, the validity of the simple equation was evaluated in a different cohort and the correlation between the step counts calculated by the simple equation and those by the detailed prediction equation were evaluated. When the step counts calculated by the simple prediction equation for all participants were compared with the measured step counts, a significant correlation was obtained among them, and the calculated values were found to be reproducible with the measured values in patients with a measured step count of <6500 by Bland−Altman plots. Furthermore, the values calculated by the simple prediction equation and those calculated by the detailed prediction equation showed a significant correlation. In conclusion, the simple prediction equation was considered reasonable.

Pulmonary function testing in COPD: looking beyond the curtain of FEV1

Chronic obstructive pulmonary disease (COPD) management remains challenging due to the high heterogeneity of clinical symptoms and the complex pathophysiological basis of the disease. Airflow limitation, diagnosed by spirometry, remains the cornerstone of the diagnosis. However, the calculation of the forced expiratory volume in the first second (FEV1) alone, has limitations in uncovering the underlying complexity of the disease. Incorporating additional pulmonary function tests (PFTs) in the everyday clinical evaluation of COPD patients, like resting volume, capacity and airway resistance measurements, diffusion capacity measurements, forced oscillation technique, field and cardiopulmonary exercise testing and muscle strength evaluation, may prove essential in tailoring medical management to meet the needs of such a heterogeneous patient population. We aimed to provide a comprehensive overview of the available PFTs, which can be incorporated into the primary care physician's practice to enhance the efficiency of COPD management.

Endoscopic lung volume reduction with endobronchial valves in very low D LCO patients: results from the German Registry - Lungenemphysemregister e.V

Background

Endoscopic lung volume reduction (ELVR) with valves has been suggested to be the key strategy for patients with severe emphysema and concomitant low diffusing capacity of the lung for carbon monoxide (D_LCO). However, robust evidence is still missing. We therefore aim to compare clinical outcomes in relation to D_LCO for patients treated with ELVR.

Methods

We assessed D_LCO at baseline and 3 months follow-up and compared pre- and postprocedural pulmonary function test, quality of life, exercise capacity and adverse events. This is a retrospective subanalysis of prospectively collected data from the German Lung Emphysema Registry.

Results

In total, 121 patients treated with ELVR were analysed. Thirty-four patients with a D_LCO ≤20% and 87 patients with a D_LCO >20% showed similar baseline characteristics. After ELVR, there was a decrease of residual volume (both p<0.001 to baseline) in both groups, and both demonstrated better quality of life (p<0.01 to baseline). Forced expiratory volume in 1 s (FEV₁) improved significantly only in patients with a D_LCO >20% (p<0.001 to baseline). Exercise capacity remained almost unchanged in both groups (p=0.3). The most frequent complication for both groups was a pneumothorax (D_LCO ≤20%: 17.6% versus D_LCO >20%: 16.1%; p=0.728). However, there were no significant differences in other adverse events between both groups.

Conclusions

ELVR improves lung function as well as quality of life in patients with D_LCO >20% and D_LCO ≤20%. Adverse events did not differ between groups. Therefore, ELVR should be considered as a treatment option, even in patients with a very low D_LCO.

Endoscopic lung volume reduction with endobronchial valves can be safely performed in patients with a very low diffusing capacity of the lung (D_LCO). Clinical effectiveness is comparable to patients with higher D_LCO.https://bit.ly/3cOgDK1

Induction of dynamic hyperinflation by expiratory resistance breathing in healthy subjects - an efficacy and safety study

New Findings

What is the central question of this study?

The study aimed to establish a novel model to study the chronic obstructive pulmonary disease (COPD)‐related cardiopulmonary effects of dynamic hyperinflation in healthy subjects.

What is the main finding and its importance?

A model of expiratory resistance breathing (ERB) was established in which dynamic hyperinflation was induced in healthy subjects, expressed both by lung volumes and intrathoracic pressures. ERB outperformed existing methods and represents an efficacious model to study cardiopulmonary mechanics of dynamic hyperinflation without potentially confounding factors as present in COPD.

Abstract

Dynamic hyperinflation (DH) determines symptoms and prognosis of chronic obstructive pulmonary disease (COPD). The induction of DH is used to study cardiopulmonary mechanics in healthy subjects without COPD‐related confounders like inflammation, hypoxic vasoconstriction and rarefication of pulmonary vasculature. Metronome‐paced tachypnoea (MPT) has proven effective in inducing DH in healthy subjects, but does not account for airflow limitation. We aimed to establish a novel model incorporating airflow limitation by combining tachypnoea with an expiratory airway stenosis. We investigated this expiratory resistance breathing (ERB) model in 14 healthy subjects using different stenosis diameters to assess a dose–response relationship. Via cross‐over design, we compared ERB to MPT in a random sequence. DH was quantified by inspiratory capacity (IC, litres) and intrinsic positive end‐expiratory pressure (PEEPi, cmH₂O). ERB induced a stepwise decreasing IC (means (95% CI): tidal breathing: 3.66 (3.45–3.88), ERB 3 mm: 3.33 (1.75–4.91), 2 mm: 2.05 (0.76–3.34), 1.5 mm: 0.73 (0.12–1.58) litres) and increasing PEEPi (tidal breathing: 0.70 (0.50–0.80), ERB 3 mm: 11.1 (7.0–15.2), 2 mm: 22.3 (17.1–27.6), 1.5 mm: 33.4 (3.40–63) cmH₂O). All three MPT patterns increased PEEPi, but to a far lesser extent than ERB. No adverse events during ERB were noted. In conclusion, ERB was proven to be a safe and efficacious model for the induction of DH and might be used for the investigation of cardiopulmonary interaction in healthy subjects.

Effect of Age on the Efficacy and Safety of Once-Daily Single-Inhaler Triple-Therapy Fluticasone Furoate/Umeclidinium/Vilanterol in Patients With COPD: A Post Hoc Analysis of the Informing the Pathway of COPD Treatment Trial

BACKGROUND

In the Informing the Pathway of COPD Treatment (IMPACT) trial, single-inhaler triple-therapy fluticasone furoate (FF), umeclidinium (UMEC), and vilanterol (VI) reduced moderate/severe exacerbation rates vs FF/VI and UMEC/VI in patients with symptomatic COPD and a history of exacerbations, with a similar safety profile.

RESEARCH QUESTION

Are trial outcomes with single-inhaler triple-therapy FF/UMEC/VI vs FF/VI and UMEC/VI affected by age in patients with symptomatic COPD and a history of exacerbations?

STUDY DESIGN AND METHODS

IMPACT was a phase III, double-blind, 52-week trial. Patients ≥ 40 years of age with symptomatic COPD and ≥ 1 moderate/severe exacerbation in the previous year were randomly assigned 2:2:1 to FF/UMEC/VI 100/62.5/25 μg, FF/VI 100/25 μg, or UMEC/VI 62.5/25 μg. End points assessed by age included annual rate of moderate/severe exacerbations, change from baseline (CFB) in trough FEV₁, proportion of St. George's Respiratory Questionnaire (SGRQ) responders (≥ 4 units decrease from baseline in SGRQ total score), and safety.

RESULTS

The intention-to-treat population comprised 10,355 patients; 4,724 (46%), 4,225 (41%), and 1,406 (14%) were ≤ 64, 65 to 74, and ≥ 75 years of age, respectively. FF/UMEC/VI reduced on-treatment moderate/severe exacerbation rates vs FF/VI (% reduction [95% CI]: ≤ 64 years, 8% [-1 to 16]; P = .070; 65-74 years, 22% [14-29]; P < .001; ≥ 75 years, 18% [3-31]; P = .021) and vs UMEC/VI (≤ 64 years, 16% [7-25]; P = .002; 65-74 years, 33% [25-41]; P < .001; ≥ 75 years, 24% [6-38]; P = .012), with greatest rate reduction seen in the 65 to 74 and ≥ 75 years subgroups. Post hoc analyses of CFB in trough FEV₁ and proportion of SGRQ responders at week 52 were significantly greater with FF/UMEC/VI than with FF/VI or UMEC/VI in all subgroups. No new safety signals were identified.

INTERPRETATION

FF/UMEC/VI reduced the rate of moderate/severe exacerbations and improved lung function and health status vs FF/VI and UMEC/VI irrespective of age for most end points, with a similar safety profile.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov; No.: NCT02164513; URL: www.clinicaltrials.govCTT116855.