Spirometric changes during exacerbations of COPD: a post hoc analysis of the WISDOM trial

Characterization of Baseline Lung Allograft Dysfunction in Single Lung Transplant Recipients

BACKGROUND

Baseline lung allograft dysfunction (BLAD) is characterized by the failure to achieve normal baseline lung function after double lung transplantation (DLTX) and is associated with a high risk of mortality. In single lung transplant (SLTX) recipients, however, cutoff values and associated factors have not been explored. Here, we aimed to define BLAD in SLTX recipients, investigate its impact on allograft survival, and identify potential risk factors for BLAD in SLTX recipients.

METHODS

We performed a retrospective, single-center analysis of the LTX cohort of LMU Munich between 2010 and 2018. In accordance with DLTX cutoffs, BLAD in SLTX recipients was defined as failure to achieve percentage of forced expiratory volume in 1 s and percentage of forced vital capacity of >60% on 2 consecutive tests >3 wk apart. Survival analysis and regression analysis for potential predictors of BLAD were performed.

RESULTS

In a cohort of 141 SLTX recipients, 43% of patients met BLAD criteria. SLTX recipients with BLAD demonstrated impaired survival. Native lung hyperinflation was associated with BLAD in obstructive disease, whereas donor/recipient lung size mismatch was associated with BLAD in both obstructive and restrictive underlying diseases. Pulmonary function testing at 3 mo after lung transplantation predicted normal baseline lung function in SLTX recipients with obstructive lung disease.

CONCLUSIONS

BLAD in SLTX recipients is as relevant as in DLTX recipients and should generally be considered in the follow-up of LTX recipients. Risk factors for BLAD differed between underlying obstructive and restrictive lung disease. A better understanding of associated factors may help in the development of preventive strategies.

Evaluating Adherence to the 2023 Canadian Thoracic Society Chronic Obstructive Pulmonary Disease Pharmacotherapy Guidelines: A Hospital-Based Study

Background

A previous study at Montfort Hospital (Ottawa, Ontario, Canada) found that only one-fifth of patients treated in 2022 for a severe acute exacerbation of chronic obstructive pulmonary disease (AECOPD) were prescribed the appropriate inhaled therapy at discharge. The revised 2023 Canadian Thoracic Society (CTS) COPD pharmacotherapy guidelines now recommend inhaled triple therapy as initial maintenance treatment in patients at high risk of AECOPD.

Objectives

The primary objective of this study was to determine if adherence to the CTS guidelines significantly improved following the publication of the 2023 statement. A secondary objective was to review the proportion of patients receiving appropriate optimization based on whether they were treated exclusively in the emergency department (ED) or required hospitalization.

Design

Retrospective study.

Methods

Subjects treated for AECOPD in the first 12 months after the publication of the 2023 guidelines were reviewed. Patient characteristics and inhaled therapy were charted. Adherence to the guidelines was compared to the prior cohort from 2022.

Results

A total of 169 patients were treated for AECOPD. After excluding individuals who died in the hospital and those who were maintained on inhaled triple therapy, 74 were candidates for review of their inhaled therapy. 27% received recommended medication optimization at discharge compared to 20% in 2022 (P = 0.25). Adherence to the guidelines significantly improved for hospitalized patients (51% vs 27%, P = 0.02). Only 5% of subjects treated exclusively in the ED received appropriate inhaler optimization. The most common deviations from the guidelines were the continued use of prior therapy (35%) and the lack of any long-acting medication (22%).

Conclusions

Adherence to the CTS COPD pharmacotherapy guidelines remained very low in ED-treated patients. The findings highlight the need for structured COPD care plans.

Remote Patient Monitoring and Machine Learning in Acute Exacerbations of Chronic Obstructive Pulmonary Disease: Dual Systematic Literature Review and Narrative Synthesis

BACKGROUND

Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are associated with high mortality, morbidity, and poor quality of life and constitute a substantial burden to patients and health care systems. New approaches to prevent or reduce the severity of AECOPD are urgently needed. Internationally, this has prompted increased interest in the potential of remote patient monitoring (RPM) and digital medicine. RPM refers to the direct transmission of patient-reported outcomes, physiological, and functional data, including heart rate, weight, blood pressure, oxygen saturation, physical activity, and lung function (spirometry), directly to health care professionals through automation, web-based data entry, or phone-based data entry. Machine learning has the potential to enhance RPM in chronic obstructive pulmonary disease by increasing the accuracy and precision of AECOPD prediction systems.

OBJECTIVE

This study aimed to conduct a dual systematic review. The first review focuses on randomized controlled trials where RPM was used as an intervention to treat or improve AECOPD. The second review examines studies that combined machine learning with RPM to predict AECOPD. We review the evidence and concepts behind RPM and machine learning and discuss the strengths, limitations, and clinical use of available systems. We have generated a list of recommendations needed to deliver patient and health care system benefits.

METHODS

A comprehensive search strategy, encompassing the Scopus and Web of Science databases, was used to identify relevant studies. A total of 2 independent reviewers (HMGG and CM) conducted study selection, data extraction, and quality assessment, with discrepancies resolved through consensus. Data synthesis involved evidence assessment using a Critical Appraisal Skills Programme checklist and a narrative synthesis. Reporting followed PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines.

RESULTS

These narrative syntheses suggest that 57% (16/28) of the randomized controlled trials for RPM interventions fail to achieve the required level of evidence for better outcomes in AECOPD. However, the integration of machine learning into RPM demonstrates promise for increasing the predictive accuracy of AECOPD and, therefore, early intervention.

CONCLUSIONS

This review suggests a transition toward the integration of machine learning into RPM for predicting AECOPD. We discuss particular RPM indices that have the potential to improve AECOPD prediction and highlight research gaps concerning patient factors and the maintained adoption of RPM. Furthermore, we emphasize the importance of a more comprehensive examination of patient and health care burdens associated with RPM, along with the development of practical solutions.

Increased Risk of Severe Cardiovascular Events Following Exacerbations of Chronic Obstructive Pulmonary Disease: Results of the EXACOS-CV Study in Japan

INTRODUCTION

Severe exacerbations of chronic obstructive pulmonary disease (COPD) are known to increase the risk of cardiovascular events. However, this association has not been investigated specifically in patients with COPD in Japan, whose characteristics may differ from those of Western patients (i.e., western Europe, the US, and Canada).

METHODS

This longitudinal retrospective cohort study analyzed secondary claims data and included patients aged ≥ 40 years with COPD (International Classification of Diseases-10 codes J41-J44). All exacerbations occurring during follow-up were measured. Time-dependent Cox models were used to estimate hazard ratios (HRs) for the association between time periods following an exacerbation of COPD (vs. time prior to a first exacerbation) and occurrence of a first hospitalization for a severe fatal or non-fatal cardiovascular event.

RESULTS

The analysis included 152,712 patients with COPD with a mean age of 73.8 years and 37.6% of whom were female. During a median follow-up of 37 months, 63,182 (41.4%) patients experienced ≥ 1 exacerbation and 13,314 (8.7%) patients experienced ≥ 1 severe cardiovascular event. Following an exacerbation of COPD, the risk of a severe cardiovascular event was increased in the first 30 days [adjusted HR (aHR) 1.44, 95% confidence interval (CI) 1.33-1.55] and remained elevated for 365 days post-exacerbation (aHR 1.13, 95% CI 1.04-1.23). Specifically, the risks of acute coronary syndrome or arrhythmias remained significantly increased for up to 180 days, and the risk of decompensated heart failure for 1 year.

CONCLUSION

Among Japanese patients with COPD, the risk of experiencing a severe cardiovascular event increased following a COPD exacerbation and remained elevated for 365 days, emphasizing the need to prevent exacerbations.

[Chronic obstructive pulmonary disease (COPD): eosinophilia and novel drug therapies]

BACKGROUND

The phenotyping of chronic obstructive pulmonary disease (COPD) has increasingly gained attention in recent years, as it leads to new and individualized therapeutic concepts.

OBJECTIVE

The aim is to provide an overview of the heterogeneity of COPD and to summarize current drug therapy concepts, particularly in the context of eosinophilic airway inflammation.

DATA

Several prospective, randomized, placebo-controlled studies have shown a reduction in exacerbations and overall mortality with inhaled triple therapy using an inhaled corticosteroid and dual bronchodilation. The higher the eosinophils in the blood, the greater the expected effect. In addition, a reduction in exacerbations with biologics in COPD with eosinophilia has been demonstrated for dupilumab. Eosinophil-guided therapy for acute exacerbations is the subject of current research.

CONCLUSION

For COPD without exacerbations, dual bronchodilation forms the basis of inhaled therapy. With exacerbations, inhaled triple therapy is indicated for patients with a blood eosinophil count of ≥ 300/µl. This type of treatment may also be useful when eosinophils are between 100 and 300/µl. Therapy with dupilumab is a possible option for the eosinophilic phenotype in the near future.

The disruptive effects of COPD exacerbation-associated factors on epithelial repair responses

Introduction

Exacerbations of chronic obstructive pulmonary disease (COPD) increase mortality risk and can lead to accelerated loss of lung function. The increased inflammatory response during exacerbations contributes to worsening of airflow limitation, but whether it also impacts epithelial repair is unclear. Therefore, we studied the effect of the soluble factor micro-environment during COPD exacerbations on epithelial repair using an exacerbation cocktail (EC), composed of four factors that are increased in COPD lungs during exacerbations (IL-1β, IL-6, IL-8, TNF-α).

Methods

Mouse organoids (primary CD31-CD45-Epcam+ cells co-cultured with CCL206 fibroblasts) were used to study epithelial progenitor behavior. Mature epithelial cell responses were evaluated using mouse precision cut lung slices (PCLS). The expression of epithelial supportive factors was assessed in CCL206 fibroblasts and primary human lung fibroblasts.

Results

EC exposure increased the number and size of organoids formed, and upregulated Lamp3, Muc5ac and Muc5b expression in day 14 organoids. In PCLS, EC imparted no effect on epithelial marker expression. Pre-treatment of CCL206 fibroblasts with EC was sufficient to increase organoid formation. Additionally, the expression of Il33, Tgfa and Areg was increased in CCL206 fibroblasts from EC treated organoids, but these factors individually did not affect organoid formation or size. However, TGF-α downregulated Foxj1 expression and upregulated Aqp5 expression in day 14 organoids.

Conclusions

EC exposure stimulates organoid formation and growth, but it alters epithelial differentiation. EC changes the epithelial progenitor support function of fibroblasts which contributes to observed effects on epithelial progenitors.

Implications of Cardiopulmonary Risk for the Management of COPD: A Narrative Review

Chronic obstructive pulmonary disease (COPD) constitutes a major global health burden and is the third leading cause of death worldwide. A high proportion of patients with COPD have cardiovascular disease, but there is also evidence that COPD is a risk factor for adverse outcomes in cardiovascular disease. Patients with COPD frequently die of respiratory and cardiovascular causes, yet the identification and management of cardiopulmonary risk remain suboptimal owing to limited awareness and clinical intervention. Acute exacerbations punctuate the progression of COPD in many patients, reducing lung function and increasing the risk of subsequent exacerbations and cardiovascular events that may lead to early death. This narrative review defines and summarises the principles of COPD-associated cardiopulmonary risk, and examines respiratory interventions currently available to modify this risk, as well as providing expert opinion on future approaches to addressing cardiopulmonary risk.

Mortality prevention as the centre of COPD management

COPD is a major healthcare problem and cause of mortality worldwide. COPD patients at increased mortality risk are those who are more symptomatic, have lower lung function and lower diffusing capacity of the lung for carbon monoxide, decreased exercise capacity, belong to the emphysematous phenotype and those who have concomitant bronchiectasis. Mortality risk seems to be greater in patients who experience COPD exacerbations and in those who suffer from concomitant cardiovascular and/or metabolic diseases. To predict the risk of death in COPD patients, several composite scores have been created using different parameters. In previous years, large studies (also called mega-trials) have evaluated the efficacy of different therapies on COPD mortality, but until recently only nonpharmaceutical interventions have proven to be effective. However, recent studies on fixed combinations of triple therapy (long-acting β-agonists, long-acting muscarinic antagonists and inhaled corticosteroids) have provided encouraging results, showing for the first time a reduction in mortality compared to dual therapies. The aim of the present review is to summarise available data regarding mortality risk in COPD patients and to describe pharmacological therapies that have shown effectiveness in reducing mortality.

Rate of severe exacerbations, healthcare resource utilisation and clinical outcomes in patients with COPD in low-income and middle-income countries: results from the EXACOS International Study

INTRODUCTION

The EXAcerbations of Chronic obstructive lung disease (COPD) and their OutcomeS (EXACOS) International Study aimed to quantify the rate of severe exacerbations and examine healthcare resource utilisation (HCRU) and clinical outcomes in patients with COPD from low-income and middle-income countries.

METHODS

EXACOS International was an observational, cross-sectional study with retrospective data collection from medical records for a period of up to 5 years. Data were collected from 12 countries: Argentina, Brazil, Chile, Colombia, Costa Rica, Dominican Republic, Guatemala, Hong Kong, Mexico, Panama, Russia and Taiwan. The study population comprised patients ≥40 years of age with COPD. Outcomes/variables included the prevalence of severe exacerbations, the annual rate of severe exacerbations and time between severe exacerbations; change in lung function over time (measured by the forced expiratory volume in 1 s (FEV1)); peripheral blood eosinophil counts (BECs) and the prevalence of comorbidities; treatment patterns; and HCRU.

RESULTS

In total, 1702 patients were included in the study. The study population had a mean age of 69.7 years, with 69.4% males, and a mean body mass index of 26.4 kg/m2. The mean annual prevalence of severe exacerbations was 20.1%, and 48.4% of patients experienced ≥1 severe exacerbation during the 5-year study period. As the number of severe exacerbations increased, the interval between successive exacerbations decreased. A statistically significant decrease in mean (SD) FEV1 from baseline to post-baseline was observed in patients with ≥1 severe exacerbation (1.23 (0.51) to 1.13 (0.52) L; p=0.0000). Mean BEC was 0.198 x109 cells/L, with 64.7% of patients having a BEC ≥0.1 x109 cells/L and 21.3% having a BEC ≥0.3 x109 cells/L. The most common comorbidity was hypertension (58.3%). An increasing number of severe exacerbations per year was associated with greater HCRU.

DISCUSSION

The findings presented here indicate that effective treatment strategies to prevent severe exacerbations in patients with COPD remain a significant unmet need in low-income and middle-income countries.

Effect on Physical Position of Peak Inspiratory Flow in Stable COPD: An Observational Study

Background

We examined the effect of physical position on peak inspiratory flow (PIF) in patients with chronic obstructive pulmonary disease (COPD) using dry-powder inhalers (DPIs) with low‑medium internal resistance (R2) and/or high internal resistance (R5).

Methods

This prospective study in stable, ambulatory patients with spirometry-confirmed COPD evaluated the effect of 3 physical positions on maximal PIF achieved. Participants had PIFs of 30-90L/min (R5) or 60-90L/min (R2 DPIs) using the In-Check™ DIAL. PIF was measured in triplicate randomly in 3 positions that patients might be in while using their inhaler (standing, sitting, and semi-upright [supine position with the head of the bed at 45°, neck flexed forward]) against prescribed DPI resistance (R2/R5/both). Correlations between PIF and percentage decline in PIF between positions and differences in participant characteristics with >10% versus ≤10% PIF decline standing to semi-upright were calculated.

Results

A total of 76 participants (mean age, 65.2 years) had positional measurements; 59% reported seated DPI use at home. The mean (standard deviation) PIF standing, sitting, and semi-upright was 80.7 (13.4), 77.8 (14.3), and 74.0 (14.5) L/min, respectively, for R2 and 51.1 (9.52), 48.6 (9.84), and 45.8 (7.69) L/min, respectively, for R5 DPIs. PIF semi-upright was significantly lower than sitting and standing (R2; P < 0.0001) and standing (R5; P= 0.002). Approximately half of the participants had >10% decline in PIF from standing to semi-upright. Patient characteristics exceeding the 0.10 absolute standardized difference threshold with the decline in PIF for both the R2 and R5 DPIs were waist-to-hip ratio, modified Medical Research Council dyspnea score, and postbronchodilator percentage predicted forced vital capacity and PIF by spirometry.

Conclusions

PIF was significantly affected by physical position regardless of DPI resistance. PIF was highest when standing and lowest when semi-upright. We recommend that patients with COPD stand while using an R2 or R5 DPI. Where unfeasible, the position should be sitting rather than semi-upright. ClinicalTrials.gov identifier NCT04168775.

Quantifying variation in home spirometry in people with cystic fibrosis during baseline health, and associations with clinical outcomes

BACKGROUND

Home spirometry is increasingly used to monitor lung function in people with cystic fibrosis (pwCF). Although decreases in lung function in the setting of increased respiratory symptoms are consistent with a pulmonary exacerbation (PEx), the interpretation of home spirometry during asymptomatic periods of baseline health is unclear. The aims of this study were to determine the variation in home spirometry in pwCF during asymptomatic periods of baseline health and to identify associations between this variation and PEx.

METHODS

Near-daily home spirometry measurements were obtained from a cohort of pwCF enrolled in a long-term study of the airway microbiome. Associations between the degree of variation in home spirometry and the time to next PEx were evaluated.

RESULTS

Thirteen subjects (mean age of 29 years and mean percent predicted forced expiratory volume in one second [ppFEV1] of 60) provided a median of 204 spirometry readings taken during 40 periods of baseline health. The mean week-to-week within-subject level of variation in ppFEV1 was 15.2 ± 6.2%. The degree of variation in ppFEV1 during baseline health was not associated with time to PEx.

CONCLUSIONS

Variation in ppFEV1 measured with near-daily home spirometry in pwCF during periods of baseline health exceeded the variation in ppFEV1 expected in clinic spirometry (based on ATS guidelines). The degree of variation in ppFEV1 during baseline health was not associated with time to PEx. These data are relevant for guiding interpretation of home spirometry.

Filling the gaps in the evaluation and selection of mobile health technologies in respiratory medicine

INTRODUCTION

Mobile health (mHealth) technology in respiratory medicine is a fast-growing and promising digital technology that is popular among patients and healthcare providers (HCPs). They provide reminders and step-by-step instructions for the correct inhalation technique, monitor patients' adherence to treatment, and facilitate communication between patients and HCPs.

AREAS COVERED

While numerous mHealth apps have been developed over the years, most applications do not have supporting evidence. Selecting the best mHealth app in respiratory medicine is challenging due to limited studies carrying out mHealth app selection. Although mHealth technologies play an important part in the future of respiratory medicine, there is no single guide on the evaluation and selection of mHealth technologies for patients with pulmonary diseases. This paper aims to provide an overview of mHealth technologies, particularly emphasizing digital inhalers and standalone applications used in asthma. Additionally, it offers insights into the evaluation, selection, and pertinent considerations surrounding mHealth applications in respiratory medicine.

EXPERT OPINION

Evaluating mHealth apps will take time, resources, and collaboration between stakeholders such as governmental regulatory bodies, subject-matter experts, and industry representatives. Filling the gaps in the evaluation and selection of the mHealth app will improve clinical decision-making, personalized treatments, self-management and disease monitoring in respiratory medicine.

Impact of COPD on mortality: An 8-year observational retrospective healthcare claims database cohort study

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is one of the leading causes of morbidity and mortality. Here we present a large observational study on the association of COPD and exacerbations with mortality (AvoidEx Mortality).

METHODS

A real-world, observational cohort study with longitudinal analyses of German healthcare claims data in patients ≥40 years of age with a COPD diagnosis from 2011 to 2018 (n = 250,723) was conducted. Patients entered the cohort (index date) upon the first COPD diagnosis. To assess the impact of COPD on all-cause death, a propensity score-matched control group of non-COPD patients was constructed. The number and severity of exacerbations during a 12-month pre-index period were used to form subgroups. For each exacerbation subgroup the exacerbations during 12 months prior to death were analysed.

RESULTS

COPD increases the all-cause mortality risk by almost 60% (HR 1.57 (95% CI 1.55-1.59)) in comparison to matched non-COPD controls, when controlling for other baseline covariates. The cumulative risk of death after 8 years was highest in patients with a history of more than one moderate or severe exacerbation. Among all deceased COPD patients, 17.2% had experienced a severe, and 34.8% a moderate exacerbation, within 3 months preceding death. Despite increasing exacerbation rates towards death, more than the half of patients were not receiving any recommended pharmacological COPD therapy in the year before death.

CONCLUSION

Our study illustrates the impact of COPD on mortality risk and highlights the need for consequent COPD management comprising exacerbation assessment and treatment.

Severe Acute Exacerbations of Chronic Obstructive Pulmonary Disease: Are There Significant Differences Between Hospitalized and Emergency Department Patients?

Rationale

Current guidelines define a severe acute exacerbation of chronic obstructive pulmonary disease (AECOPD) as an increase in symptoms requiring hospital admission or emergency department (ED) visit. Little is known about whether or not subjects requiring hospitalization and those needing only ED care have similar patient profiles and if their clinical outcomes appear comparable.

Objective

The main goals of this study were to compare the demographic and clinical characteristics of patients treated for an AECOPD with an inpatient admission versus an ED visit and to review if hospital resource utilization was different between the 2 groups after discharge.

Methods

Subjects treated in 2022 at Montfort Hospital for an AECOPD were reviewed. Patient demographic information was collected in addition to spirometry results and blood eosinophil counts on file. Supplemental oxygen use and medication lists were also recorded. Patients with an initial hospital admission were compared to those requiring only ED care with univariate and multivariate analyses. We also assessed if subjects were again treated for an AECOPD up to 6 months post initial discharge, and if so, the type of hospital visits (hospitalization or ED).

Measurements and Main Results

A total of 135 individuals necessitated hospitalization and 79 received ED care for the treatment of an AECOPD. On univariate analysis, patients requiring an inpatient stay appeared older and were more likely to have spirometry results on file. A greater proportion of hospitalized individuals were on supplemental oxygen and prescribed at least one long-acting inhaled medication. These studied variables remained significant after multivariate logistic regression analysis. Subjects with an initial inpatient admission were also more likely to require hospitalization upon repeat presentation for a severe AECOPD.

Conclusion

Given the important differences observed in both patient characteristics and hospital resource utilization, this study supports considering an AECOPD requiring inpatient admission versus an ED visit as distinct categories of events.

The initial angle of the maximum expiratory flow-volume curve: a novel start-of-test criteria of spirometry in children

The aim of the present study was to define an initial angle called β and to assess its diagnostic value for identifying poor-quality maneuvers in spirometry testing in children. Furthermore, its predictive equation or normal value was explored. Children aged 4-14 years with respiratory symptoms who underwent spirometry were enrolled. Based on the efforts labeled during maneuvering and the quality control criteria of the guidelines, children were categorized into good-quality and poor-quality groups. According to ventilatory impairment, children in the good-quality group were divided into three subgroups: normal, restricted, and obstructed. Angle β was the angle between the line from the expiratory apex to the origin of coordinates and the x-axis of the maximal expiratory flow-volume (MEFV) curve. Demographic characteristics, angle β, and other spirometric parameters were compared among groups. The diagnostic values of angle β, forced expiratory time (FET), and their combination were assessed using receiver operating characteristic curves. Data from 258 children in the good-quality group and 702 healthy children in our previous study were used to further explore the predictive equation or normal value of angle β. The poor-quality group exhibited a significantly smaller angle β (76.44° vs. 79.36°; P < 0.001), significantly lower peak expiratory flow (PEF), FET, and effective FET (ETe), and significantly higher expiratory volume at peak flow rate (FEV-PEF) and ratio of extrapolated volume and forced vital capacity (EV/FVC) than the good-quality group. There was no significant difference in angle β among the normal, restricted, and obstructed groups. Logistic regression analysis revealed that smaller angle β and FET values indicated poor-quality MEFV curves. The combination of angle β < 74.58° and FET < 4.91 s had a significantly larger area under the curve than either one alone. The normal value of angle β of children aged 4-14 years was 78.40 ± 0.12°.   Conclusions: Angle β contributes to the quality control evaluation of spirometry in children. Both angle β < 74.58° and FET < 4.91 s are predictors of poor-quality MEFV curves, while their combination offers the highest diagnostic value. What is Known: • A slow start is one of the leading causes of poor-quality maximal expiratory flow-volume (MEFV) curves, which is a particularly prominent issue among children due to limited cooperation, especially those younger than 6 years old. • It is relatively difficult to differentiate between ventilatory dysfunction and poor cooperation when a slow start occurs in children; therefore, there is an urgent need for an objective indicator that is unaffected by ventilatory impairment to evaluate quality control of spirometry. What is New: • The initial angle β, which was introduced at the ascending limb of the MEFV curve in the present study, has a certain diagnostic value for poor-quality MEFV curves in children. • Angle β < 74.58° is a predictor of poor-quality MEFV curves, and its combination with FET < 4.91 s offers a higher diagnostic value.

Sniff and reverse-sniff nasal respiratory pressures after exacerbation of chronic obstructive pulmonary disease: A single-center prospective study

BACKGROUND

and objective: This study examined the validity of sniff nasal inspiratory (SNIP) and reverse-sniff nasal expiratory pressures (RSNEP) for estimating respiratory muscle strength and for predicting poor life expectancy following exacerbation in patients with chronic obstructive pulmonary disease (COPD).

METHODS

This prospective study included patients who were admitted for COPD exacerbation and underwent rehabilitation. At hospital discharge, SNIP, RSNEP, and maximum mouth inspiratory (MIP) and expiratory pressures (MEP) were measured, and the body mass index, degree of airflow obstruction, dyspnea, and exercise capacity (BODE) index was calculated by evaluating body mass index, forced expiratory volume in 1 s (FEV1), the Modified Medical Research Council Dyspnea Scale, and 6-min walk distance.

RESULTS

Data from 43 patients (mean age 76.8 years, FEV1 42.8 % predicted) were analyzed. SNIP and RSNEP were moderately correlated with MIP and MEP, respectively. Bland-Altman plot means of SNIP (48.3 ± 17.5) and RSNEP (44.7 ± 23.8 cmH2O) were lower than those of MIP (54.8 ± 19.9) and MEP (76.4 ± 31.2 cmH2O), respectively, and the SNIP-MIP and RSNEP-MEP 95 % limits of agreement were wide. Logistic regression showed that SNIP and RSNEP were significantly associated with BODE score ≥7 (poor life expectancy), and predictive accuracy was 81.4 % when combining SNIP ≤49 and RSNEP ≤42 cmH2O.

CONCLUSION

After exacerbation in patients with COPD, SNIP and RSNEP are useful indicators that complement MIP and MEP. Furthermore, a combined SNIP and RSNEP test may be beneficial in predicting poor life expectancy.

Implementing an Evidence-Based COPD Hospital Discharge Protocol: A Narrative Review and Expert Recommendations

Discharge bundles, comprising evidence-based practices to be implemented prior to discharge, aim to optimise patient outcomes. They have been recommended to address high readmission rates in patients who have been hospitalised for an exacerbation of chronic obstructive pulmonary disease (COPD). Hospital readmission is associated with increased morbidity and healthcare resource utilisation, contributing substantially to the economic burden of COPD. Previous studies suggest that COPD discharge bundles may result in fewer hospital readmissions, lower risk of mortality and improvement of patient quality of life. However, evidence for their effectiveness is inconsistent, likely owing to variable content and implementation of these bundles. To ensure consistent provision of high-quality care for patients hospitalised with an exacerbation of COPD and reduce readmission rates following discharge, we propose a comprehensive discharge protocol, and provide evidence highlighting the importance of each element of the protocol. We then review care bundles used in COPD and other disease areas to understand how they affect patient outcomes, the barriers to implementing these bundles and what strategies have been used in other disease areas to overcome these barriers. We identified four evidence-based care bundle items for review prior to a patient's discharge from hospital, including (1) smoking cessation and assessment of environmental exposures, (2) treatment optimisation, (3) pulmonary rehabilitation, and (4) continuity of care. Resource constraints, lack of staff engagement and knowledge, and complexity of the COPD population were some of the key barriers inhibiting effective bundle implementation. These barriers can be addressed by applying learnings on successful bundle implementation from other disease areas, such as healthcare practitioner education and audit and feedback. By utilising the relevant implementation strategies, discharge bundles can be more (cost-)effectively delivered to improve patient outcomes, reduce readmission rates and ensure continuity of care for patients who have been discharged from hospital following a COPD exacerbation.

High use of short-acting β2-agonists in COPD is associated with an increased risk of exacerbations and mortality

Background

Short-acting β₂-agonist (SABA) overuse has been associated with an increased risk of exacerbations in asthma; however, less is known about SABA use in COPD. Our aim was to describe SABA use and investigate potential associations between high SABA use and the risk of future exacerbations and mortality in COPD.

Methods

This observational study identified COPD patients in primary care medical records in Sweden. Data were linked to the National Patient Registry, the Prescribed Drug Registry and the Cause of Death Registry. The index date was 12 months after the date of COPD diagnosis. During a 12-month prior to index baseline period, information on SABA use was collected. Patients were followed with respect to exacerbations and mortality for 12 months post index.

Results

Of the 19 794 COPD patients included (mean age 69.1 years, 53.3% females), 15.5% and 7.0% had collected ≥3 or ≥6 SABA canisters during the baseline period, respectively. A higher level of SABA use (≥6 canisters) was independently associated with a higher risk of both moderate and severe exacerbations (hazard ratio (HR) 1.28 (95% CI 1.17‒1.40) and 1.76 (95% CI 1.50‒2.06), respectively) during follow-up. In total, 673 (3.4%) patients died during the 12-month follow-up period. An independent association was found between high SABA use and overall mortality (HR 1.60, 95% CI 1.07‒2.39). This association, however, was not found in patients using inhaled corticosteroids as maintenance treatment.

Conclusion

In COPD patients in Sweden, high SABA use is relatively common and associated with a higher risk of exacerbations and all-cause mortality.

The effect of exacerbations on lung density in α1-antitrypsin deficiency

Background

Acute exacerbations of COPD (AECOPD) have unclear impacts on emphysema measurement using computed tomography (CT)-derived 15th percentile lung density (PD15). The aim of this study was to assess the influence of AECOPD on PD15 lung density in α₁-antitrypsin deficiency.

Methods

In a post hoc analysis of the RAPID (Randomised Trial of Augmentation Therapy in α₁-Proteinase Inhibitor Deficiency) trial, raw marginal residuals of PD15 (measured - predicted) were determined by fitting a regression line to individual patient CT data. These deviations from the expected slope were compared by age, sex, baseline forced expiratory volume in 1 s, diffusing capacity of the lungs for carbon monoxide % predicted and PD15, inhaled corticosteroid use and treatment group.

Results

Positive and negative residuals (reflecting higher or lower lung density than predicted from regression) were observed, which declined in magnitude over time following AECOPD events. Logistic regression confirmed a limited effect of patient characteristics on the absolute size of residuals, whereas AECOPD within 6 weeks of CT had a notable effect versus no AECOPD within 6 weeks (OR 5.707, 95% CI 3.375-9.652; p<0.0001).

Conclusion

AECOPD result in higher or lower CT lung density estimates; the effect is greatest in the 2 weeks immediately after an AECOPD and persists for <6 weeks. Patient characteristics were less relevant than AECOPD within 6 weeks, supporting the reliability of PD15 as a measure of lung density. An exacerbation-free period prior to CT scan is advisable to reduce signal-to-noise ratio in future clinical trials.

Integrating digital inhalers into clinical care of patients with asthma and chronic obstructive pulmonary disease

Modernizing inhaled medications through digital technology can help address persistent problems of non-adherence and poor inhaler technique in patients with obstructive lung diseases. With a growing body of supportive clinical studies, advances in digital inhaler sensors and platforms, greater support from payers and healthcare organizations, significant growth with these technologies is expected. While all digital (smart) inhalers record adherence, these are distinguished by their compatibility with commercial inhalers, capabilities to guide inhaler technique, use of patient-reported outcomes, and user-friendliness for both the healthcare professional (HCP) and patient. Due to the complexity and novelty of employing digital inhalers, collaboration with multiple entities within health systems is necessary and a well-planned integration is needed. For HCPs and patients, cybersecurity and privacy are critical, it will require review by each healthcare organization. In the US, some payers reimburse for remote monitoring using digital inhalers, but reimbursement is currently unavailable in other countries. There are several models for remote patient care, as employing an active, ongoing digital interface between the HCP and patient or they may choose to only review data at clinical encounters. Personalization of therapies and feedback are key to success. While digital inhaler malfunction uncommonly occurs, patient attrition over a year is significant. Some patients will be challenged to use digital platforms or have the necessary technology. Additional research is needed to address cost-effectiveness, in vivo accuracy of inspiratory measurement capable devices, ability to teach inhaler technique, their application for monitoring lung function, and lastly real-world adoption and implementation in routine clinical practice.

Prediction of COPD acute exacerbation in response to air pollution using exosomal circRNA profile and Machine learning

Ambient fine particulate matter (PM2.5) is linked to an increased risk of chronic obstructive pulmonary disease (COPD) exacerbations, which significantly increase the risk of mortality in COPD patients. Identifying the subtype of COPD patients who are sensitive to environmental aggressions is necessary. Using in vitro and in vivo PM2.5 exposure models, we demonstrate that exosomal hsa_circ_0005045 is upregulated by PM2.5 and binds to the protein cargo peroxiredoxin2, which functionally aggravates hallmarks of COPD by recruiting neutrophil elastase and triggering in situ release of tumor necrosis factor (TNF)-α by inflammatory cells. The biological function of hsa_circ_0005045 associated with aggravation of COPD is validated using exosome-transplantation and conditional circRNA-knockdown murine models. By sorting the major components of PM2.5, we find that PM2.5-bound heavy metals, which are distinguishable from the components of cigarette smoke, trigger the elevation of exosomal hsa_circ_0005045. Finally, using machine learning models in a cohort with 327 COPD patients, the PM2.5 exposure-sensitive COPD patients are characterized by relatively high hsa_circ_0005045 expression, non-smoking, and group C (mMRC 0-1 (or CAT < 10) and ≥ 2 exacerbations (or ≥ 1 exacerbation leading to hospital admission) in the past year). Thus, our results suggest that environmental reduction in PM2.5 emission provides a targeted approach to protecting non-smoking COPD patients against air pollution-related disease exacerbation.

Effect of timing of bronchodilator therapy initiation on exacerbations in patients with chronic obstructive pulmonary disease: a retrospective cohort study

Background

The benefit of prompt vs delayed treatment initiation with inhaled long-acting bronchodilators in reducing exacerbations in chronic obstructive pulmonary disease (COPD) is unclear. This study aimed to investigate if long-acting bronchodilator therapy initiation within 30 days of COPD diagnosis reduces exacerbation risk in patients with COPD.

Methods

This was a retrospective cohort study of patients with COPD based on claims and electronic medical records data extracted from the Real World Data database. The index date (day 0) was the date of the first confirmed inpatient or outpatient COPD diagnosis between January 1, 2005, and December 31, 2018. Patients with COPD without an asthma diagnosis and aged ≥ 40 years at the index date were included. Patients who initiated inhaled long-acting bronchodilator therapy within the first 30 days (day 0 to day 29) were categorized into the “prompt therapy” group and the rest into the “delayed therapy” group. Time from day 30 post-diagnosis to the first exacerbation and annual exacerbation rate (AER) were evaluated for the overall population and those stratified by COPD phenotype, including chronic bronchitis (CB) and emphysema.

Results

Compared with the delayed therapy group (n = 1516), time to first exacerbation was prolonged (hazard ratio 0.78; 95% confidence interval [CI] [0.70, 0.87]) and annual rates of moderate or severe exacerbations were lower (rate ratio 0.74; 95% CI [0.65, 0.84]) in the prompt therapy group (n = 1466). Similarly, time to first exacerbation was prolonged and AERs were lower in the prompt therapy group in the subgroups of patients with CB or emphysema.

Conclusions

This is the first study to demonstrate a prolonged time to first exacerbation upon initiation of long-acting bronchodilators within 30 days of COPD diagnosis. A beneficial effect was also observed in patients with CB and emphysema. Our data support advising patients to initiate long-acting bronchodilators soon after COPD diagnosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02184-6.

A machine-learning-based prediction method for easy COPD classification based on pulse oximetry clinical use

Chronic Obstructive Pulmonary Disease (COPD) is a progressive, obstructive lung disease that restricts airflow from the lungs. COPD patients are at risk of sudden and acute worsening of symptoms called exacerbations. Early identification and classification of COPD exacerbation can reduce COPD risks and improve patient’s healthcare and management. Pulse oximetry is a non-invasive technique used to assess patients with acutely worsening symptoms. As part of manual diagnosis based on pulse oximetry, clinicians examine three warning signs to classify COPD patients. This may lack high sensitivity and specificity which requires a blood test. However, laboratory tests require time, further delayed treatment and additional costs. This research proposes a prediction method for COPD patients’ classification based on pulse oximetry three manual warning signs and the resulting derived few key features that can be obtained in a short time. The model was developed on a robust physician labeled dataset with clinically diverse patient cases. Five classification algorithms were applied on the mentioned dataset and the results showed that the best algorithm is XGBoost with the accuracy of 91.04%, precision of 99.86%, recall of 82.19%, F1 measure value of 90.05% with an AUC value of 95.8%. Age, current and baseline heart rate, current and baseline pulse ox. (SPO2) were found the top most important predictors. These findings suggest the strength of XGBoost model together with the availability and the simplicity of input variables in classifying COPD daily living using a (wearable) pulse oximeter.

COPD - do the right thing

A gap exists between guidelines and real-world clinical practice for the management and treatment of chronic obstructive pulmonary disease (COPD). Although this has narrowed in the last decade, there is room for improvement in detection rates, treatment choices and disease monitoring. In practical terms, primary care practitioners need to become aware of the huge impact of COPD on patients, have non-judgemental views of smoking and of COPD as a chronic disease, use a holistic consultation approach and actively motivate patients to adhere to treatment.This article is based on discussions at a virtual meeting of leading Nordic experts in COPD (the authors) who were developing an educational programme for COPD primary care in the Nordic region. The article aims to describe the diagnosis and lifelong management cycle of COPD, with a strong focus on providing a hands-on, practical approach for medical professionals to optimise patient outcomes in COPD primary care.

Inferring COPD Severity from Tidal Breathing

OBJECTIVE

To develop an algorithm that can infer the severity level of a COPD patient's airflow limitation from tidal breathing data that is collected by a wearable device.

METHODS

Data was collected from 25 single visit adult volunteers with a confirmed or suspected diagnosis of chronic obstructive pulmonary disease (COPD). The ground truth airflow limitation severity of each subject was determined by applying the Global Initiative for Chronic Obstructive Lung Disease (GOLD) staging criteria to the subject's spirometry results. Spirometry was performed in a pulmonary function test laboratory under the supervision of trained clinical staff. Separately, the subjects' respiratory signal was measured during quiet breathing, and a classification model was built to infer the subjects' level of airflow limitation from the measured respiratory signal. The classification model was evaluated against the ground truth using leave-one-out testing.

RESULTS

Severity of airway obstruction was classified as either mild/moderate or severe/very severe with an accuracy of 96.4%.

CONCLUSION

Tidal breathing parameters that are measured with a wearable device can be used to distinguish between different levels of airflow limitation in COPD patients.

Challenges and Pitfalls of Using Repeat Spirometry Recordings in Routine Primary Care Data to Measure FEV1 Decline in a COPD Population

Background

Electronic healthcare records (EHR) are increasingly used in epidemiological studies but are often viewed as lacking quality compared to randomised control trials and prospective cohorts. Studies of patients with chronic obstructive pulmonary disease (COPD) often use the rate of forced expiratory volume in 1 second (FEV₁) decline as an outcome; however, its definition and robustness in EHR have not been investigated. We aimed to investigate how the rate of FEV₁ decline differs by the criteria used in an EHR database.

Methods

Clinical Practice Research Datalink and Hospital Episode Statistics were used. Patient populations were defined using 8 sets of criteria around repeated FEV₁ measurements. At a minimum, patients had a diagnosis of COPD, were ≥35 years old, were current or ex-smokers, and had data recorded from 2004. FEV₁ measurements recorded during follow-up were identified. Thereafter, eight populations were defined based on criteria around: i) the exclusion of patients or individual measurements with potential measurement error; ii) minimum number of FEV₁ measurements; iii) minimum time interval between measurements; iv) specific timing of measurements; v) minimum follow-up time; and vi) the use of linked data. For each population, the rate of FEV₁ decline was estimated using mixed linear regression.

Results

For 7/8 patient populations, rates of FEV₁ decline (age and sex adjusted) were similar and ranged from −18.7mL/year (95% CI −19.2 to −18.2) to −16.5mL/year (95% CI −17.3 to −15.7). Rates of FEV₁ decline in populations that excluded patients with potential measurement error ranged from −79.4mL/year (95% CI −80.7 to −78.2) to −46.8mL/year (95% CI −47.6 to −46.0).

Conclusion

FEV₁ decline remained similar in a COPD population regardless of number of FEV₁ measurements, time intervals between measurements, follow-up period, exclusion of specific FEV₁ measurements, and linkage to HES. However, exclusion of individuals with questionable data led to selection bias and faster rates of decline.

Prevalence and characteristics of chronic obstructive pulmonary disease in China with a diagnostic criterion of FEV1/FVC less than the lower limit of normal-a reanalysis of Chinese epidemiological survey of COPD (CESCOPD) study

Background

To reappraise the prevalence and characteristics of chronic obstructive pulmonary disease (COPD) in China with a criterion of FEV₁/FVC < the lower limit of normal (LLN).

Methods

We assessed the incidence and characteristics of airflow limitation using data from the Chinese Epidemiological Survey of COPD study-a multicenter, randomized trial, with an age-dependent LLN reference equation [established by the Guangzhou Institute of Respiratory Health (GIRH)]. Questionnaire and spirometry data were collected for all eligible subjects. COPD prevalence, risk factors, severity distribution, as well as comparisons of characteristics between the LLN and 0.7 were analyzed.

Results

COPD prevalence was 9.0% among participants aged 40-80 years in China with the criterion of LLN. Greater prevalence was observed in female sex, rural areas and never smokers than with the GOLD 0.7 fixed ratio. Age distribution showed a higher incidence of COPD in people under 60 years but lower in participants over 60 years of age. With the LLN FEV₁ reference equation, patients in stage I were decreased (15.8% vs. 24.6%, P<0.001), while the proportion of patients in stage III and IV were increased when compared with the China 2002 revised equation (27.7% vs. 21.1%, for stage III, P<0.001; 8.7% vs. 5.6% for stage IV, P=0.001). Only 30.8% of patients with COPD had ever been "diagnosed" with COPD and 60.6% of the patients had respiratory symptoms, both lower than that under the GOLD 0.7 fixed-ratio criterion (35.5%, P=0.004; 64.8% for symptoms, P=0.014).

Conclusions

With the GIRH-LLN criterion, COPD prevalence was slightly higher, and a large number of women, rural patients and nonsmokers with young age and little symptoms were diagnosed when compared with GOLD 0.7 fixed ratio. These subjects may, therefore, deserve further attention and may warrant regular follow-up.

Trial Registration

Registration number: ChiCTR-ECS-13004110.

Digital Inhalers for Asthma or Chronic Obstructive Pulmonary Disease: A Scientific Perspective

Impressive advances in inhalation therapy for patients with asthma and chronic obstructive pulmonary disease (COPD) have occurred in recent years. However, important gaps in care remain, particularly relating to poor adherence to inhaled therapies. Digital inhaler health platforms which incorporate digital inhalers to monitor time and date of dosing are an effective disease and medication management tool, promoting collaborative care between clinicians and patients, and providing more in-depth understanding of actual inhaler use. With advances in technology, nearly all inhalers can be digitalized with add-on or embedded sensors to record and transmit data quantitating inhaler actuations, and some have additional capabilities to evaluate inhaler technique. In addition to providing an objective and readily available measure of adherence, they allow patients to interact with the device directly or through their self-management smartphone application such as via alerts and recording of health status. Clinicians can access these data remotely and during patient encounters, to better inform them about disease status and medication adherence and inhaler technique. The ability for remote patient monitoring is accelerating interest in and the use of these devices in clinical practice and research settings. More than 20 clinical studies of digital inhalers in asthma or COPD collectively show improvement in medication adherence, exacerbation risk, and patient outcomes with digital inhalers. These studies support previous findings about patient inhaler use and behaviors, but with greater granularity, and reveal some new findings about patient medication-taking behaviors. Digital devices that record inspiratory flows with inhaler use can guide proper inhaler technique and may prove to be a clinically useful lung function measure. Adoption of digital inhalers into practice is still early, and additional research is needed to determine patient and clinician acceptability, the appropriate place of these devices in the therapeutic regimen, and their cost effectiveness.

An Inhaled PI3Kδ Inhibitor Improves Recovery in Acutely Exacerbating COPD Patients: A Randomized Trial

Purpose

This study evaluated the safety and efficacy of inhaled nemiralisib, a phosphoinositide 3-kinase δ (PI3Kδ) inhibitor, in patients with an acute exacerbation of chronic obstructive pulmonary disease (COPD).

Methods

In this double-blind, placebo-controlled study, 126 patients (40–80 years with a post-bronchodilator forced expiratory volume in 1 sec (FEV₁) ≤80% of predicted (previously documented)) were randomized 1:1 to once daily inhaled nemiralisib (1 mg) or placebo for 84 days, added to standard of care. The primary endpoint was specific imaging airway volume (siVaw) after 28 treatment days and was analyzed using a Bayesian repeated measures model (clintrials.gov: NCT02294734).

Results

A total of 126 patients were randomized to treatment; 55 on active treatment and 49 on placebo completed the study. When comparing nemiralisib and placebo-treated patients, an 18% placebo-corrected increase from baseline in distal siVaw (95% credible intervals (Cr I) (−1%, 42%)) was observed on Day 28. The probability that the true treatment ratio was >0% (Pr(θ>0)) was 96%, suggestive of a real treatment effect. Improvements were observed across all lung lobes. Patients treated with nemiralisib experienced a 107.3 mL improvement in posterior median FEV₁ (change from baseline, 95% Cr I (−2.1, 215.5)) at day 84, compared with placebo. Adverse events were reported by 41 patients on placebo and 49 on nemiralisib, the most common being post-inhalation cough on nemiralisib (35%) vs placebo (3%).

Conclusion

These data show that addition of nemiralisib to usual care delivers more effective recovery from an acute exacerbation and improves lung function parameters including siVaw and FEV₁. Although post-inhalation cough was identified, nemiralisib was otherwise well tolerated, providing a promising novel therapy for this acutely ill patient group.

The Ventilatory Strategy to Minimize Expiratory Flow Rate in Ventilated Patients with Chronic Obstructive Pulmonary Disease

Although the pathophysiology of chronic obstructive pulmonary disease (COPD) is multifactorial, central airway collapse is reported to have a great impact on symptom severity. In COPD patients, positive pressure formed by hyperinflated lungs compressing the tracheal wall and negative changes in intratracheal static pressure due to rapid expiratory flow velocity at the beginning of expiration collapse the trachea. This phenomenon can be explained by fluid dynamics theory. Our hypothesis is that ventilatory strategy focusing on minimization of expiratory flow rate may be advantageous for patients receiving mechanical ventilation for COPD. If appropriate counter pressure could be applied on exhalation, patients may be able to exhale slowly with reduced expiratory flow rates which may prevent negative changes of the intratracheal static pressure. We devised a new conceptual ventilation mode “minimized expiratory flow rate ventilation (MExV)” which applies regulated counter pressure on exhalation. The conceptual waveforms of “minimized expiratory flow rate ventilation” including flow rate, volume, and airway pressure are shown, compared with typical waveforms of the conventional ventilation modes.

Sit-to-stand tests in patients hospitalised for chronic obstructive pulmonary disease exacerbation: association with pulmonary function tests and risk of future exacerbations

Background/Aims

The sit-to-stand test is a quick and cost-effective measure of exercise tolerance and lower body strength. The literature focuses on its use in stable patients with chronic obstructive pulmonary disease. This study in patients hospitalised for chronic obstructive pulmonary disease exacerbation aimed to investigate possible associations of the sit-to-stand test with pulmonary function and risk of future acute exacerbations.

Methods

This study was conducted on a sample of 22 patients with chronic obstructive pulmonary disease. Participants' clinical details were recorded before they undertook spirometry, 30-second and five-repetition sit-to-stand tests. Participants were assessed via a structured telephone interview for the occurrence of acute exacerbation events in the 12 months following discharge.

Results

Patients were classified based on the presence or absence of acute exacerbations of chronic obstructive pulmonary disease over 12 months. A negative correlation was observed between five-repetition sit-to-stand test performance time and number of repetitions during the 30-second sit-to-stand test; longer sit-to-stand times and fewer repetitions were observed in patients who experienced exacerbations during follow up. The 30-second sit-to-stand test repetitions correlated positively with forced expiratory volume in 1 second (FEV1). Five-repetition sit-to-stand test performance correlated negatively with FEV1, FEV1% predicted, forced vital capacity and FEV1/forced vital capacity ratio. From the various exercise parameters, five-repetition sit-to-stand test performance time demonstrated a moderate ability to predict exacerbations.

Conclusions

This study is the first to focus on the use of the sit-to-stand tests in inpatients with acute exacerbation of chronic obstructive pulmonary disease. There was a significant correlation between the 30-second sit-to-stand test and five-repetition sit-to-stand test results. Both tests were associated with pulmonary function indices and risk of future chronic obstructive pulmonary disease exacerbations.

Advances in spirometry testing for lung function analysis

Introduction: Spirometry, the most common lung function test, is used to evaluate individuals with respiratory complaints or known respiratory disease. However, its underutilization and the misinterpretation of its parameters are causes for concern. Areas covered: This review describes new spirometry-derived metrics, new reference equations, recent recommendations for presentation of results, recent spirometry-based prevalence studies, and technological advances in spirometry equipment. Expert opinion: The underutilization of spirometry can be overcome by increasing access to portable, hand-held, and user-friendly spirometers, together with strategies that increase awareness of the importance of spirometry. New metrics derived from spirometry, together with traditional spirometric criteria, can identify individuals with structural lung disease and respiratory morbidity. Some problems with the reference equations were solved by the Global Lung Function Initiative (GLI), which covers a wider age range and more ethnic groups and provides limits of normality using the z-score. Despite these advantages, the GLI equations lack data from large populations (especially those from Africa, South Asia, and Latin America) and greater representation of older people. Another disadvantage attributed to the GLI is the lack of predicted values for peak expiratory flow and other airflows, limiting the interpretation of the maximal expiratory flow-volume curve.