Trajectory of Preserved Ratio Impaired Spirometry: Natural History and Long-Term Prognosis

Physiological Characterization of Preserved Ratio Impaired Spirometry in the CanCOLD Study: Implications for Exertional Dyspnea and Exercise Intolerance

Rationale: It is increasingly recognized that adults with preserved ratio impaired spirometry (PRISm) are prone to increased morbidity. However, the underlying pathophysiological mechanisms are unknown. Objectives: Evaluate the mechanisms of increased dyspnea and reduced exercise capacity in PRISm. Methods: We completed a cross-sectional analysis of the CanCOLD (Canadian Cohort Obstructive Lung Disease) population-based study. We compared physiological responses in 59 participants meeting PRISm spirometric criteria (post-bronchodilator FEV1 < 80% predicted and FEV1/FVC ⩾ 0.7), 264 control participants, and 170 ever-smokers with chronic obstructive pulmonary disease (COPD), at rest and during cardiopulmonary exercise testing. Measurements and Main Results: Individuals with PRISm had lower total lung, vital, and inspiratory capacities than healthy controls (all P < 0.05) and minimal small airway, pulmonary gas exchange, and radiographic parenchymal lung abnormalities. Compared with healthy controls, individuals with PRISm had higher dyspnea/[Formula: see text]o2 ratio at peak exercise (4.0 ± 2.2 vs. 2.9 ± 1.9 Borg units/L/min; P < 0.001) and lower [Formula: see text]o2peak (74 ± 22% predicted vs. 96 ± 25% predicted; P < 0.001). At standardized submaximal work rates, individuals with PRISm had greater Vt/inspiratory capacity (Vt%IC; P < 0.001), reflecting inspiratory mechanical constraint. In contrast to participants with PRISm, those with COPD had characteristic small airways dysfunction, dynamic hyperinflation, and pulmonary gas exchange abnormalities. Despite these physiological differences among the three groups, the relationship between increasing dyspnea and Vt%IC during cardiopulmonary exercise testing was similar. Resting IC significantly correlated with [Formula: see text]o2peak (r = 0.65; P < 0.001) in the entire sample, even after adjusting for airflow limitation, gas trapping, and diffusing capacity. Conclusions: In individuals with PRISm, lower exercise capacity and higher exertional dyspnea than healthy controls were mainly explained by lower resting lung volumes and earlier onset of dynamic inspiratory mechanical constraints at relatively low work rates. Clinical trial registered with www.clinicaltrials.gov (NCT00920348).

Prevalence, Medicaid use and mortality risk of low FEV1 in adults aged 20-35 years old in the USA: evidence from a population-based retrospective cohort study

BACKGROUND

The prevalence, Medicaid use and mortality risk associated with low forced expiratory volume in 1 s (FEV1) among young adults aged 20-35 years are not well understood, despite its potential implications for the development of chronic pulmonary disease and overall prognosis.

METHODS

A retrospective cohort study was conducted among young adults aged 20-35 years old, using data from the National Health and Nutrition Examination Survey, National Death Index and Centers for Medicare & Medicaid Services. Participants were categorised into a low FEV1 group (pre-bronchodilator FEV1%pred <80%) and a normal FEV1 group (FEV1%pred ≥80%). Weighted logistic regression analysis was employed to identify the risk factors associated with low FEV1, while Cox proportional hazard models were used to calculate the hazard ratio (HR) for Medicaid use and the all-cause mortality between the two groups.

RESULTS

A total of 5346 participants aged 20-35 were included in the study, with 329 in the low FEV1 group and 5017 in the normal group. The weighted prevalence of low FEV1 among young adults was 7.1% (95% CI 6.0 to 8.2). Low body mass index (OR=3.06, 95% CI 1.79 to 5.24), doctor-diagnosed asthma (OR=2.25, 1.28 to 3.93), and wheezing or whistling (OR=1.57, 1.06 to 2.33) were identified as independent risk factors for low FEV1. Over a 15-year follow-up, individuals in the low FEV1 group exhibited a higher likelihood of Medicaid use compared with those in the normal group (HR=1.73, 1.07 to 2.79). However, there was no statistically significant increase in the risk of all-cause mortality over a 30-year follow-up period (HR=1.48, 1.00 to 2.19).

CONCLUSIONS

A considerable portion of young adults demonstrated low FEV1 levels, a characteristic that was associated with a higher risk of Medicaid use over a long-term follow-up, yet not linked to an augmented risk of all-cause mortality.

Lung-function trajectories: relevance and implementation in clinical practice

Lung development starts in utero and continues during childhood through to adolescence, reaching its peak in early adulthood. This growth is followed by gradual decline due to physiological lung ageing. Lung-function development can be altered by several host and environmental factors during the life course. As a result, a range of lung-function trajectories exist in the population. Below average trajectories are associated with respiratory, cardiovascular, metabolic, and mental health comorbidities, as well as with premature death. This Review presents progressive research into lung-function trajectories and assists the implementation of this knowledge in clinical practice as an innovative approach to detect poor lung health early, monitor respiratory disease progression, and promote lung health. Specifically, we propose that, similar to paediatric height and weight charts used globally to monitor children's growth, lung-function charts could be used for both children and adults to monitor lung health status across the life course. To achieve this proposal, we introduce our free online Lung Function Tracker tool. Finally, we discuss challenges and opportunities for effective implementation of the trajectory concept at population level and outline an agenda for crucial research needed to support such implementation.

Preserved Ratio Impaired Spirometry (PRISm): A Global Epidemiological Overview, Radiographic Characteristics, Comorbid Associations, and Differentiation from Chronic Obstructive Pulmonary Disease

Preserved Ratio Impaired Spirometry (PRISm) manifests notable epidemiological disparities across the globe, with its prevalence and influential factors showcasing pronounced diversities among various geographical territories and demographics. The prevalence of PRISm fluctuates considerably among regions such as Latin America, the United States, and Asian nations, potentially correlating with a myriad of determinants, including socioeconomic status, environmental factors, and lifestyle modalities. Concurrently, the link between PRISm and health risks and other disorders, especially its distinction and interrelation with chronic obstructive pulmonary disease (COPD), has become a pivotal subject of scientific enquiry. Radiographic anomalies, such as perturbations in the pulmonary parenchyma and structural alterations, are posited as salient characteristics of PRISm. Furthermore, PRISm unveils intricate associations with multiple comorbidities, inclusive of hypertension and type 2 diabetes, thereby amplifying the intricacy in comprehending and managing this condition. In this review, we aim to holistically elucidate the epidemiological peculiarities of PRISm, its potential aetiological contributors, its nexus with COPD, and its association with radiographic aberrations and other comorbidities. An integrative understanding of these dimensions will provide pivotal insights for the formulation of more precise and personalised preventative and therapeutic strategies.

Sex and HIV Differences in Preserved Ratio Impaired Spirometry (PRISm) Among Ugandans Postpneumonia

Background

Preserved ratio impaired spirometry (PRISm), defined as a normal ratio of forced expiratory volume in 1 second (FEV1) to forced vital capacity (≥0.70) with low FEV1 (<80% predicted), has been associated with increased mortality in the general population. Female sex has been associated with increased odds of PRISm in people without HIV. People with HIV (PWH) are at increased risk for lung function abnormalities, but whether HIV modifies the effect of sex on PRISm development is largely unknown.

Methods

Adults with and without HIV underwent baseline followed by serial spirometry after completing therapy for pneumonia, predominantly tuberculosis (TB), in Kampala, Uganda. Using generalized estimating equations adjusted for age, body mass index, smoking, biomass fuel exposure, HIV, and TB status, we compared individuals with PRISm with those with normal spirometry. These models were stratified by HIV status.

Results

Of 339 baseline participants, 153 (45%) were women; 129 (38%) had HIV, of whom 53% were women. Overall, 105/339 participants (31%) had PRISm at baseline. HIV was associated with lower odds of PRISm (adjusted odds ratio [aOR], 0.38; 95% CI, 0.21-0.68; P = .001). Female sex trended toward increased odds of PRISm among all participants (aOR, 1.65; 95% CI, 0.99-2.75; P = .052). The association between female sex and PRISm tended to be stronger among PWH (aOR, 3.16; 95% CI, 1.14-8.76; P = .03) than among those without HIV (aOR, 1.34; 95% CI, 0.73-2.45; P = .34); this study was underpowered to detect an HIV-sex interaction of this magnitude (P = .30).

Conclusions

Among Ugandan adults who recovered from pneumonia, female sex was associated with increased odds and HIV with decreased odds of PRISm, suggesting independent sex and HIV effects on PRISm pathogenesis.

Acute Exacerbation and Longitudinal Lung Function Change of Preserved Ratio Impaired Spirometry

Background

Preserved ratio impaired spirometry (PRISm) is a heterogeneous disease entity. Limited data are available regarding its prevalence, clinical course, or prognosis. We aimed to evaluate the longitudinal clinical course of patients with PRISm compared with chronic obstructive pulmonary disease (COPD).

Methods

A retrospective study enrolled PRISm and COPD patients who underwent chest computed tomography and longitudinal pulmonary function tests between January 2013 and December 2020. We compared the incidence of acute exacerbations and lung function changes between PRISm and COPD patients.

Results

Of the 623 patients, 40 and 583 had PRISm and COPD, respectively. Compared to COPD patients, PRISm patients were younger, more likely to be female and have a history of tuberculosis, and less likely to be smokers. They also had less severe comorbidities, lower forced vital capacity (FVC) and diffusing capacity of the lungs for carbon monoxide (DLCO). The clinical course was not significantly different between the PRISm and COPD patients in terms of the risk of moderate-to-severe acute exacerbations or proportion of frequent exacerbators. During follow-up, PRISm patients had a significantly slower annual decline of forced expiratory volume in 1 second, FVC, and DLCO than COPD patients.

Conclusion

PRISm patients had no significant difference in the risk of acute exacerbations, but a significantly slower decline of lung function during longitudinal follow-up, compared with COPD patients.

The many faces of COPD in real life: a longitudinal analysis of the NOVELTY cohort

Background

The diagnosis of COPD requires the demonstration of non-fully reversible airflow limitation by spirometry in the appropriate clinical context. Yet, there are patients with symptoms and relevant exposures suggestive of COPD with either normal spirometry (pre-COPD) or preserved ratio but impaired spirometry (PRISm). Their prevalence, clinical characteristics and associated outcomes in a real-life setting are unclear.

Methods

To investigate them, we studied 3183 patients diagnosed with COPD by their attending physician included in the NOVELTY study (clinicaltrials.gov identifier NCT02760329), a global, 3-year, observational, real-life cohort that included patients recruited from both primary and specialist care clinics in 18 countries.

Results

We found that 1) approximately a quarter of patients diagnosed with (and treated for) COPD in real life did not fulfil the spirometric diagnostic criteria recommended by the Global Initiative for Chronic Obstructive Lung Disease (GOLD), and could be instead categorised as pre-COPD (13%) or PRISm (14%); 2) disease burden (symptoms and exacerbations) was highest in GOLD 3-4 patients (exacerbations per person-year (PPY) 0.82) and lower but similar in those in GOLD 1-2, pre-COPD and PRISm (exacerbations range 0.27-0.43 PPY); 3) lung function decline was highest in pre-COPD and GOLD 1-2, and much less pronounced in PRISm and GOLD 3-4; 4) PRISm and pre-COPD were not stable diagnostic categories and change substantially over time; and 5) all-cause mortality was highest in GOLD 3-4, lowest in pre-COPD, and intermediate and similar in GOLD 1-2 and PRISm.

Conclusions

Patients diagnosed COPD in a real-life clinical setting present great diversity in symptom burden, progression and survival, warranting medical attention.

Clinical relevance of lung function trajectory clusters in middle-aged and older adults

Background

The determinants and health outcomes of lung function trajectories in adults among the general population are poorly understood. We aimed to identify and characterise clusters of lung function trajectories in adults aged ≥45 years.

Methods

Gaussian finite-mixture modelling was applied to baseline and annualised change of forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and FEV1/FVC ratio z-scores in participants of the Rotterdam Study, a prospective population-based cohort study, with repeated spirometry (n=3884; mean±sd age 64.7±8.9 years). Longitudinal outcomes were all-cause mortality, respiratory outcomes (symptoms, COPD (FEV1/FVC <0.7 in absence of asthma), preserved ratio impaired spirometry (PRISm; FEV1/FVC ≥0.7 and FEV1 or FVC <80%)), smoking cessation and weight changes. Independent risk factors, including genetics, were identified by multiple logistic regression.

Results

We identified eight trajectory clusters, with the reference group having persistently normal spirometry (prevalence 42.8%). Three clusters showed higher mortality, adjusted for confounders: 1) the persistently low FEV1 cluster (prevalence 6.8%, hazard ratio (HR) 1.71, 95% CI 1.37-2.13); 2) rapid FEV1 decliners (prevalence 4.6%, HR 1.48, 95% CI 1.10-1.99); and 3) FVC decliners (prevalence 3.7%, HR 1.49, 95% CI 1.09-2.03). In contrast, FVC improvers (prevalence 6.7%, HR 0.61, 95% CI 0.41-0.90) and persistently high FEV1 (prevalence 29.2%, HR 0.82, 95% CI 0.69-0.98) were protective trajectory clusters. Clusters were characterised by differences in genetic predisposition (polygenic scores of FEV1 and FEV1/FVC), demographics, cigarette smoking, respiratory symptoms (chronic cough, wheezing and dyspnoea), cardiovascular factors (body mass index, hypertension and heart failure) and serum C-reactive protein levels. Frailty, weight changes and the development of respiratory symptoms, COPD and PRISm were significantly associated with trajectory clusters.

Conclusions

This study reveals clinically relevant lung function trajectory clusters in older adults of the general population.

Impact of preserved ratio impaired spirometry on coronary artery calcium score progression: a longitudinal cohort study

Background

Preserved ratio impaired spirometry (PRISm) is associated with increased cardiovascular disease (CVD) risk and mortality. However, a causal relationship between PRISm and CVD remains unclear. We investigated the progression of coronary artery calcium (CAC) scores based on the presence of PRISm and reduced forced vital capacity (FVC).

Methods

This retrospective cohort study included 11 420 participants aged ≥40 years with forced expiratory volume in 1 s (FEV1)/FVC ≥0.7 who underwent at least two health screening examinations with coronary computed tomography scan between 2003 and 2020, and were without a history of CVD or interstitial lung disease. Participants with PRISm, defined as FEV1/FVC ≥0.7 and FEV1 <80% predicted, were further divided by low FVC (FVC <80% predicted). We estimated the 5-year progression rates of CAC by comparing participants with and without PRISm at baseline using mixed linear models.

Results

Of the 11 420 participants, 8536 (75%), 811 (7%) and 2073 (18%) had normal spirometry, PRISm with normal FVC and PRISm with low FVC, respectively. During the mean (range) follow-up of 6.0 (0.5-17.2) years, the multivariable adjusted ratio of 5-year CAC progression rates comparing participants with PRISm to those with normal spirometry was 1.08 (95% CI 1.04-1.13). This rate was higher in participants with PRISm with low FVC (1.21 (95% CI 1.12-1.30)) than in those with normal FVC.

Conclusion

In this longitudinal cohort study of subjects without a history of CVD, PRISm was significantly associated with CAC progression, which was more evident in the group with PRISm and low FVC.

All-cause and cause-specific mortality by spirometric pattern and sex - a population-based cohort study

BACKGROUND

Chronic airway obstruction (CAO) and restrictive spirometry pattern (RSP) are associated with mortality, but sex-specific patterns of all-cause and specific causes of death have hardly been evaluated.

OBJECTIVES

To study the possible sex-dependent differences of all-cause mortality and patterns of cause-specific mortality among men and women with CAO and RSP, respectively, to that of normal lung function (NLF).

DESIGN

Population-based prospective cohort study.

METHODS

Individuals with CAO [FEV1/vital capacity (VC) < 0.70], RSP [FEV1/VC ⩾ 0.70 and forced vital capacity (FVC) < 80% predicted] and NLF (FEV1/VC ⩾ 0.70 and FVC ⩾ 80% predicted) were identified within the Obstructive Lung Disease in Northern Sweden (OLIN) studies in 2002-2004. Mortality data were collected through April 2016, totally covering 19,000 patient-years. Cox regression and Fine-Gray regression accounting for competing risks were utilized to estimate hazard ratios (HRs) with 95% confidence intervals (CIs) adjusted for age, body mass index, sex, smoking habits and pack-years.

RESULTS

The adjusted hazard for all-cause mortality was higher in CAO and RSP than in NLF (HR, 95% CI; 1.69, 1.31-2.02 and 1.24, 1.06-1.71), and the higher hazards were driven by males. CAO had a higher hazard of respiratory and cardiovascular death than NLF (2.68, 1.05-6.82 and 1.40, 1.04-1.90). The hazard of respiratory death was significant in women (3.41, 1.05-11.07) while the hazard of cardiovascular death was significant in men (1.49, 1.01-2.22). In RSP, the higher hazard for respiratory death remained after adjustment (2.68, 1.05-6.82) but not for cardiovascular death (1.11, 0.74-1.66), with a similar pattern in both sexes.

CONCLUSION

The higher hazard for all-cause mortality in CAO and RSP than in NLF was male driven. CAO was associated with respiratory death in women and cardiovascular death in men, while RSP is associated with respiratory death, similarly in both sexes.

Association of preserved ratio impaired spirometry with mortality: a systematic review and meta-analysis

BACKGROUND

Preserved ratio impaired spirometry (PRISm) is prevalent within the general population. Increased mortality has been reported among subjects with PRISm, but the evidence has never been summarised. This systematic review aims to synthesise evidence on the association between PRISm and the risk of all-cause, cardiovascular and respiratory-related mortality.

METHODS

We systematically searched MEDLINE, Embase and Web of Science for population-based cohort studies from inception to April 2023 using the terms related to impaired spirometry and mortality. Titles and abstracts were screened to identify eligible studies that reported mortality estimates for individuals with PRISm. We excluded studies that adopted other definitions of impaired spirometry, had a specific study setting (e.g. HIV patients), had an insufficient follow-up period (<1 year) or reported duplicated data. Random-effects meta-analysis was used to produce pooled hazard ratio (HR) with 95% confidence intervals. Between-study heterogeneity was assessed with I2.

RESULTS

Eight studies met the inclusion criteria involving 40 699 individuals with PRISm. All included studies reported increased risk of all-cause mortality among adults with PRISm. Meta-analysis showed that PRISm was associated with an increased risk of all-cause mortality (pooled HR 1.71, 95% CI 1.51-1.93; I2=64%), cardiovascular mortality (pooled HR 1.57, 95% CI 1.44-1.72; I2=35%) and respiratory-related mortality (pooled HR 1.97, 95% CI 1.55-2.49; I2=0%).

CONCLUSIONS

Individuals with PRISm have a significantly increased risk of mortality compared with those with normal spirometry.

Impact of the metabolic syndrome on cardiopulmonary morbidity and mortality in individuals with lung function impairment: a prospective cohort study of the Danish general population

Background

Whether the metabolic syndrome plays a role for the prognosis of individuals with lung function impairment (preserved ratio impaired spirometry (PRISm) or airflow limitation) is unclear. We hypothesised that the metabolic syndrome in individuals with lung function impairment is associated with increased cardiopulmonary morbidity and mortality.

Methods

The Copenhagen General Population Study was initiated in 2003 based on a random sample of white men and women aged 20-100 years drawn from the Danish general population. The risk of ischemic heart disease/heart failure, respiratory disease, and all-cause mortality was analysed with Cox models adjusted for age, sex, current smoking, and asthma during 15 years of follow-up.

Findings

Among 106,845 adults, 86,159 had normal lung function, 6126 had PRISm, and 14,560 had airflow limitation. We observed 10,448 hospital admissions for ischemic heart disease/heart failure, 21,140 for respiratory disease, and 11,125 deaths. Individuals with versus individuals without the metabolic syndrome generally had higher 5-year absolute risk of all outcomes, including within those with normal lung function, mild-moderate-severe PRISm, and very mild-mild-moderate-severe airflow limitation alike. Compared to individuals without the metabolic syndrome and with normal lung function, those with both the metabolic syndrome and severe PRISm had hazard ratios of 3.74 (95% CI: 2.53-5.55; p < 0.0001) for ischemic heart disease/heart failure, 5.02 (3.85-6.55; p < 0.0001) for respiratory disease, and 5.32 (3.76-7.54; p < 0.0001) for all-cause mortality. Corresponding hazard ratios in those with both the metabolic syndrome and severe airflow limitation were 2.89 (2.34-3.58; p < 0.0001) for ischemic heart disease/heart failure, 5.98 (5.28-6.78; p < 0.0001) for respiratory disease, and 4.16 (3.50-4.95; p < 0.0001) for all-cause mortality, respectively. The metabolic syndrome explained 13% and 27% of the influence of PRISm or airflow limitation on ischemic heart disease/heart failure and all-cause mortality.

Interpretation

The metabolic syndrome conferred increased risk of cardiopulmonary morbidity and mortality at all levels of lung function impairment.

Funding

Danish Lung Foundation, Danish Heart Foundation, Capital Region of Copenhagen, and Boehringer Ingelheim. JV is supported by the NIHR Manchester BRC.

Preserved Ratio Impaired Spirometry and Risks of Macrovascular, Microvascular Complications and Mortality Among Individuals With Type 2 Diabetes

BACKGROUND

The prospective associations of preserved ratio impaired spirometry (PRISm) with new-onset macrovascular and microvascular complications and mortality among individuals with type 2 diabetes (T2D) and whether PRISm enhances the prediction ability of an established office-based risk score remain to be elucidated.

RESEARCH QUESTION

Can PRISm be used as a predictor of poor prognosis in individuals with T2D?

STUDY DESIGN AND METHODS

We included 20,047 study participants with T2D and complete data on spirometry at recruitment from the UK Biobank cohort. Multivariable Cox proportional hazards models were used to assess the associations of baseline PRISm (FEV1 to FVC ratio, ≥ 0.70; FEV1, < 80% predicted) with subsequent risks of incident stroke (any type), ischemic stroke, myocardial infarction, unstable angina, coronary heart disease, diabetic retinopathy, diabetic kidney disease, all-cause mortality, cardiovascular mortality, and respiratory mortality.

RESULTS

For this cohort analysis, 4,521 patients (22.55% of participants with T2D) showed comorbid PRISm at baseline. Over a median follow-up of 11.52 to 11.87 years, patients with T2D with PRISm at baseline showed higher risks than those with normal spirometry findings of various T2D complications developing and mortality; the adjusted hazard ratios for PRISm were 1.413 (95% CI, 1.187-1.681) for stroke (any type), 1.382 (95% CI, 1.129-1.690) for ischemic stroke, 1.253 (95% CI, 1.045-1.503) for myocardial infarction, 1.206 (95% CI, 1.086-1.339) for coronary heart disease, 1.311 (95% CI, 1.141-1.506) for diabetic retinopathy, 1.384 (95% CI, 1.190-1.610) for diabetic kidney disease, 1.337 (95% CI, 1.213-1.474) for all-cause mortality, 1.597 (95% CI, 1.296-1.967) for cardiovascular mortality, and 1.559 (95% CI, 1.189-2.044) for respiratory mortality, respectively. The addition of PRISm significantly improved the reclassification ability, based on the net reclassification index, of an office-based risk score by 15.53% (95% CI, 10.14%-19.63%) to 33.60% (95% CI, 20.90%-45.79%).

INTERPRETATION

Individuals with T2D with comorbid PRISm, accounting for a considerable proportion of the population with T2D, showed significantly increased risks of adverse macrovascular and microvascular complications and mortality.

Peripheral airway dysfunction in prematurity-associated obstructive lung disease identified by oscillometry

INTRODUCTION

Mechanisms underlying lung dysfunction after preterm birth are poorly understood. Studying phenotypes of prematurity-associated lung disease may aid understanding of underlying mechanisms. Preterm-born children with and without lung dysfunction and term controls were assessed using oscillometry before and after exercise, and after postexercise bronchodilation.

METHODS

Preterm-born children, born at gestation of 34 weeks or less, were classified into those with prematurity-associated obstructive lung disease (POLD; FEV1  < LLN, FEV1 /FVC < LLN), prematurity-associated preserved ratio of impaired spirometry (pPRISm; FEV1  < LLN, FEV1 /FVC ≥ LLN) and compared to preterm (FEV1  ≥ LLN) and term controls (%predicted FEV1  > 90%). All children underwent cardiopulmonary exercise, and oscillometry assessment at baseline, postexercise, and after postexercise bronchodilator administration.

RESULTS

From 241 participants aged 7-12 years, complete data were available from 179: 15 children with POLD and 11 with pPRISm were compared with 93 preterm and 60 term controls. POLD group, when compared to both control groups, had impaired impedance, greater resistance, more negative (greater magnitude) reactance at low frequencies, and also had decreased compliance. pPRISm group demonstrated impaired reactance and compliance compared to term controls. No differences were noted between the preterm and term controls. Exercise had little impact on oscillometry values, but children with POLD had greatest improvements after postexercise bronchodilator administration, with decreased resistance and decreased magnitude of reactance, particularly at low frequencies.

CONCLUSION

Preterm-born children with obstructive airway disease had the greatest oscillometry impairments and the largest improvements after postexercise bronchodilator compared to control groups. Oscillometry can potentially be used to identify preterm-born children with lung disease to institute treatment.

Clinical significance of normalized airflow obstruction in patients with chronic obstructive pulmonary disease

BACKGROUND

There is ongoing debate regarding the diagnostic criteria for chronic obstructive pulmonary disease (COPD); recent studies have focused on the early COPD detection and management. Here, we compared clinical features and prognosis in patients with FEV1/FVC<0.70 at baseline, according to normalized airflow obstruction status during follow-up.

METHODS

We used the Korea COPD Subgroup Study (KOCOSS) cohort database, a prospective nationwide observational COPD study. Normalized obstruction (NO) was defined as FEV1/FVC ≥0.7 in the 2-year follow-up period, whereas fixed obstruction (FO) was defined as FEV1/FVC <0.7. Demographic and clinical data, 1-year exacerbation risk and difference in FEV1 decline over 2 years were compared between NO and FO groups.

RESULTS

Among the 670 COPD patients with post-bronchodilator FEV1/FVC <0.7 in this study, 95 (14.2%) displayed NO. Compared with the FO group, the NO group had higher FEV1, and DLCO, body mass index, as well as lower Saint George Respiratory Questionnaire, Beck Depression Index, and Beck Anxiety Index. Blood eosinophil count, IgE level, and FeNO did not significantly differ between two groups. There was no significant difference in exacerbation frequency between the two groups, but the NO group had a significant increase in FEV1 compared with the FO group during follow-up.

CONCLUSION

Transient airflow obstruction in the NO group may represent a clinical manifestation of early COPD; close monitoring is needed for such patients.

Clinical Characteristics and Medical Utilization of Smokers with Preserved Ratio Impaired Spirometry

Purpose

To investigate the clinical characteristics and medical utilization of smokers with preserved ratio impaired spirometry (PRISm).

Patients and Methods

We used data from the Korean National Health and Nutrition Examination Survey between 2007 and 2012, linked to the Health Insurance Review and Assessment Service. Clinical characteristics and medical utilization, including inpatient admission, emergency department visit, prescribed medication, and medical cost, were retrospectively compared among three groups: normal spirometry, PRISm, and chronic obstructive pulmonary disease (COPD).

Results

A total of 7115 smokers were included (4743 normal spirometry, 689 PRISm, and 1683 COPD subjects). The mean age was the highest in the COPD group, followed by the PRISm and normal groups, and the proportion of women was the highest in the PRISm group. The tobacco exposure, socioeconomic status (SES), and schooling level of the PRISm group were at levels between those of the normal and COPD groups. However, the PRISm group had the highest proportion of current smokers, highest body mass index (BMI), and lowest mean FEV1 and FVC % predicted. During the study period, the medical utilization of 92 smokers (13.4%) in the PRISm group and 436 smokers (25.9%) in the COPD group was related to respiratory diseases. Emergency department visit or hospitalization and overall medical cost of the PRISm group were comparable to those of the COPD group, except for outpatient clinic visit. Old age, women, low BMI, low SES, low schooling level, high amount of tobacco exposure, wheezing, and decreased FEV1 and FVC % predicted were factors associated with medical utilization in PRISm.

Conclusion

Medical utilization was comparable between the PRISm and COPD groups. Smokers with PRISm who were older, women, or heavy smokers with low BMI, low SES and schooling level, wheezing, or low FEV1 and FVC might need close observation and early treatment.

Association of spirometric restriction with mortality in the silicotics: a cohort study

BACKGROUND

Restrictive spirometry pattern (RSP), defined as reduced forced vital capacity (FVC) in absence of airflow obstruction (AFO), is associated with increased risk of mortality in general population. However, evidence in the patients with silicosis is limited. This study was aimed to investigate the relationship between RSP and the risk of death in a silicotic cohort.

METHOD

This retrospective cohort study used data from the Pneumoconiosis Clinic, Hong Kong Department of Health that containing 4315 patients aged 18-80 years and diagnosed with silicosis during 1981-2019, with a follow-up till 31 December 2019. Spirometry was carried out at the diagnostic examination of silicosis. Lung function categories were classified as normal spirometry (FEV1/FVC ≥ 0.7, FVC ≥ 80% predicted), RSP only (FEV1/FVC ≥ 0.7, FVC < 80% predicted), AFO only (FEV1/FVC < 0.7, FVC ≥ 80% predicted), and RSP&AFO mixed (FEV1/FVC < 0.7, FVC < 80% predicted). The hazard ratio (HR) and 95% confidence intervals (95% CI) were computed using a Cox proportional hazards model adjusting for age, body mass index, history of tuberculosis, smoking status, pack-years, and radiographic characteristics of silicotic nodules.

RESULTS

Among the 4315 patients enrolled in the study, the prevalence of RSP was 24.1% (n = 1038), including 11.0% (n = 473) with RSP only and 13.1% (n = 565) with mixed RSP and AFO. During the follow-up period, a total of 2399 (55.6%) deaths were observed. Compared with the silicotics with normal spirometry, those with RSP only had significantly increased risk of all-cause mortality (HR = 1.63, 95% CI 1.44-1.85) and respiratory-related mortality (HR = 1.56, 95% CI 1.31-1.85). Notably, a higher risk of mortality was observed in silicotics with mixed ventilatory defects of both RSP and AFO (all-cause mortality: HR = 2.22, 95% CI 1.95-2.52; respiratory-related mortality: HR = 2.59, 95% CI 2.18-3.07) than in those with RSP only.

CONCLUSION

RSP is significantly associated with increased risk of all-cause and respiratory-related mortality in the silicotics, and patients with mixed restrictive and obstructive ventilatory defect have higher risk of mortality than those with single RSP or AFO. These findings emphasize the importance of recognizing RSP in the occupational settings, especially for the silicotic patients with mixed ventilatory defect.

Characterising airway obstructive, dysanaptic and PRISm phenotypes of prematurity-associated lung disease

INTRODUCTION

Although obstructive airway disease has been shown to be associated with prematurity, other spirometry phenotypes are less well described.

OBJECTIVES

We characterised abnormal spirometry phenotypes in preterm-born children, including prematurity-associated obstructive lung disease (POLD, forced expiratory volume in 1 s (FEV1)

METHODS

768 children, aged 7-12 years, underwent FENO measurements and spirometry before and after salbutamol. Groups were compared using parametric tests; multinomial regression was used.

RESULTS

22.6% of 544 preterm-born (mean gestation: 31 weeks) and 9.2% of 195 term-born children, with satisfactory data available, were classified into one of four abnormal spirometry groups. Each phenotype was generally more prevalent in preterm-born children than in the term-born children. For the preterm group, POLD-reversible (4.4%) was associated with increased FENO, bronchopulmonary dysplasia (BPD) and intrauterine growth restriction. POLD-fixed group (3.3%) did not have increased FENO but was associated with BPD. 41% of the pDysanapsis group (5.9%) had bronchodilator response, 31% had increased FENO and was associated with postnatal weight gain. In the pPRISm group (9%), 13% responded to bronchodilators, FENO was not increased and was non-significantly associated with body mass index (p=0.064).

CONCLUSIONS

Further to airway obstruction, we describe airway dysanapsis and pPRISm spirometry phenotypes in survivors of prematurity, both of which have poor outlook in other disease groups. By identifying specific phenotypes, targeted therapy can be developed to improve long-term outcomes.

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Key Words

• paediatric lung disaese

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MESH Headings

• Humans
• Infant, Newborn
• Bronchodilator Agents/therapeutic use
• Bronchopulmonary Dysplasia/complications
• Forced Expiratory Volume/physiology
• Lung
• Lung Diseases, Obstructive
• Pulmonary Disease, Chronic Obstructive
• Spirometry
• Vital Capacity/physiology
• Premature Birth
• Infant, Premature

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Grants

• MR/M022552/1 Medical Research Council

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Affiliation(s)

Michael Cousins Department of Child Health, Cardiff University School of Medicine, Cardiff, UK
Kylie Hart Department of Child Health, Cardiff University School of Medicine, Cardiff, UK
Sarah J Kotecha Department of Child Health, Cardiff University School of Medicine, Cardiff, UK
A John Henderson MRC Integrative Epidemiology Unit, Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
W John Watkins Department of Child Health, Cardiff University School of Medicine, Cardiff, UK
Andrew Bush Centre for Paediatrics and Child Health, Imperial College of Medicine, London, UK
Sailesh Kotecha Department of Child Health, Cardiff University School of Medicine, Cardiff, UK

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[The FEV1/VC ratio to define bronchial obstruction: Should we use a fixed ratio or the lower limit of normal?]

INTRODUCTION

While the screening of chronic obstructive lung diseases (COPD, asthma, etc.) constitutes a major public health issue in France and worldwide, simple spirometry appears currently as the key to meeting the challenge. Since description of the forced expiratory maneuver by Robert Tiffeneau in 1947, it has been admitted that the FEV1/VC ratio permits diagnosis obstructive pulmonary diseases. However, the diagnostic criteria for this ratio remain uncertain. The long-lasting debate between advocates of a 0.7 "fixed ratio" (FR) of 0.7 and advocates of the "lower limit of normal" (LLN) remains relevant.

STATE OF THE ARTS

In this general review, we describe the respective advantages of the FR and LLN criteria according to the most recently published studies, and characterize the conditions associated with discrepancies between these criteria.

PERSPECTIVES AND CONCLUSIONS

FR and LLN appear not to share similar diagnosis values and the use of both criteria facilitates proposal of an up-to-date interpretation and diagnosis strategy in the context of first-line spirometry, particularly for patients with FEV1/VC ratio in the "grey zone".

Impaired Spirometry and COPD Increase the Risk of Cardiovascular Disease: A Canadian Cohort Study

BACKGROUND

Individuals with COPD and preserved ratio impaired spirometry (PRISm) findings in clinical settings have an increased risk of cardiovascular disease (CVD).

RESEARCH QUESTION

Do individuals with mild to moderate or worse COPD and PRISm findings in community settings have a higher prevalence and incidence of CVD compared with individuals with normal spirometry findings? Can CVD risk scores be improved when impaired spirometry is added?

STUDY DESIGN AND METHODS

The analysis was embedded in the Canadian Cohort Obstructive Lung Disease (CanCOLD). Prevalence of CVD (ischemic heart disease [IHD] and heart failure [HF]) and their incidence over 6.3 years were compared between groups with impaired and normal spirometry findings using logistic regression and Cox models, respectively, adjusting for covariables. Discrimination of the pooled cohort equations (PCE) and Framingham risk score (FRS) in predicting CVD were assessed with and without impaired spirometry.

RESULTS

Participants (n = 1,561) included 726 people with normal spirometry findings and 835 people with impaired spirometry findings (COPD Global Initiative for Chronic Obstructive Lung Disease [GOLD] stage 1 disease, n = 408; GOLD stage ≥ 2, n = 331; PRISm findings, n = 96). Rates of undiagnosed COPD were 84% in GOLD stage 1 and 58% in GOLD stage ≥ 2 groups. Prevalence of CVD (IHD or HF) was significantly higher among individuals with impaired spirometry findings and COPD compared with those with normal spirometry findings, with ORs of 1.66 (95% CI, 1.13-2.43; P = .01∗) (∗ indicates statistical significane with P < .05) and 1.55 (95% CI, 1.04-2.31; P = .033∗), respectively. Prevalence of CVD was significantly higher in participants having PRISm findings and COPD GOLD stage ≥ 2, but not GOLD stage 1. CVD incidence was significantly higher, with hazard ratios of 2.07 (95% CI, 1.10-3.91; P = .024∗) for the impaired spirometry group and 2.09 (95% CI, 1.10-3.98; P = .024∗) for the COPD group compared to individuals with normal spirometry findings. The difference was significantly higher among individuals with COPD GOLD stage ≥ 2, but not GOLD stage 1. The discrimination for predicting CVD was low and limited when impaired spirometry findings were added to either risk score.

INTERPRETATION

Individuals with impaired spirometry findings, especially those with moderate or worse COPD and PRISm findings, have increased comorbid CVD compared with their peers with normal spirometry findings, and having COPD increases the risk of CVD developing.

Characterizing the urinary proteome of prematurity-associated lung disease in school-aged children

INTRODUCTION

Although different phenotypes of lung disease after preterm birth have recently been described, the underlying mechanisms associated with each phenotype are poorly understood. We, therefore, compared the urinary proteome for different spirometry phenotypes in preterm-born children with preterm- and term-born controls.

METHODS

Preterm and term-born children aged 7-12 years, from the Respiratory Health Outcomes in Neonates (RHiNO) cohort, underwent spirometry and urine collection. Urine was analysed by Nano-LC Mass-Spectrometry with Tandem-Mass Tag labelling. The preterm-born children were classified into phenotypes of prematurity-associated preserved ratio impaired spirometry (pPRISm, FEV₁ < lower limit of normal (LLN), FEV₁/FVC ≥ LLN), prematurity-associated obstructive lung disease (POLD, FEV₁ < LLN, FEV₁/FVC < LLN) and preterm controls (FEV₁ ≥ LLN,). Biological relationships between significantly altered protein abundances were analysed using Ingenuity Pathways Analysis software, and receiver operator characteristic curves were calculated.

RESULTS

Urine was analysed from 160 preterm-born children and 44 term controls. 27 and 21 were classified into the pPRISm and POLD groups, respectively. A total of 785 proteins were detected. Compared to preterm-born controls, sixteen significantly altered proteins in the pPRISm group were linked to six biological processes related to upregulation of inflammation and T-cell biology. In contrast, four significantly altered proteins in the POLD group were linked with neutrophil accumulation. Four proteins (DNASE1, PGLYRP1, B2M, SERPINA3) in combination had an area under the curve of 0.73 for pPRISm and three combined proteins (S100A8, MMP9 and CTSC) had AUC of 0.76 for POLD.

CONCLUSIONS

In this exploratory study, we demonstrate differential associations of the urinary proteome with pPRISm and POLD.

TRIAL REGISTRATION

EudraCT: 2015-003712-20.

Clinical Manifestations of Subjects With the Non-Specific Pulmonary Function Test Pattern

Introduction

Non-specific pattern (NSP) is a subgroup of preserved ratio impaired spirometry (PRISm) that requires a normal total lung capacity measurement. NSP has been historically classified as being an obstructive lung disease pattern. There has been heightened interest and investigation into PRISm recently as it has been associated with an increased likelihood of developing chronic obstructive pulmonary disease (COPD). Given the inherent challenges of understanding the clinical significance of the NSP, the aim of this study was to further explore the clinical characteristics of patients with this pulmonary function test pattern.

Material and methods

We identified 111 and 79 subjects using pre-bronchodilator (pre-BD) and post-bronchodilator (post-BD) values, respectively, that met criteria for NSP. The outpatient medical records were retrospectively reviewed for associated diagnoses that were then clustered into 'obstructive' or 'non-obstructive' groups based on the treating physician's primary pulmonary clinical diagnosis.

Results

Within this NSP cohort, cough, wheezing and sputum production were documented more frequently in those with an obstructive lung disease diagnosis. Whether identified using pre-BD or post-BD spirometric values, those with NSP and a positive BD response were more likely to carry an obstructive lung disease diagnosis.

Conclusion

Approximately one third of patients with NSP in this study were not given an obstructive lung disease diagnosis by their clinician, which supports the classification of NSP as not an exclusively obstructive lung disease pattern. However, the presence of supporting clinical symptoms, such as cough with sputum production and wheeze, and/or a positive BD response on PFT, support a diagnosis of obstruction in patients with NSP.

Trajectories of Spirometric Patterns, Obstructive and PRISm, in a Population-Based Cohort in Latin America

Background

Preserved ratio impaired spirometry (PRISm) has been associated with adverse outcomes and increased transition to other spirometric categories over time. We aimed to examine its prevalence, trajectories over time, and outcomes in a population-based sample from Latin America.

Methods

Data were obtained from two population-based surveys of adults from three cities in Latin America (PLATINO study), conducted on the same individuals 5-9 years after their baseline examination. We estimated the frequency of PRISm defined by FEV1/FVC≥0.70 with FEV1 <80%, describing their clinical characteristics, longitudinal transition trajectories over time, factors associated with the transition.

Results

At baseline, 2942 participants completed post-bronchodilator spirometry, and 2026 at both evaluations. The prevalence of normal spirometry was 78%, GOLD-stage 1 10.6%, GOLD 2-4 6.5%, and PRISm was: 5.0% (95% CI 4.2-5.8). PRISm was associated with less schooling, more reports of physician-diagnosis of COPD, wheezing, dyspnea, missing days at work, having ≥2 exacerbations in the previous year but without accelerated lung function decline. Mortality risk was significantly higher in PRISm (HR 1.97, 95% CI 1.2-3.3) and COPD GOLD 1-4 categories (HR 1.79, 95% CI 1.3-2.4) compared with normal spirometry. PRISm at baseline most frequently transitioned to another category at follow-up (46.5%); 26.7% to normal spirometry and 19.8% to COPD. The best predictors of transition to COPD were closeness of FEV1/FVC to 0.70, older age, current smoking, and a longer FET in the second assessment.

Conclusion

PRISm, is a heterogeneous and unstable condition prone to adverse outcomes that require adequate follow-up.

Preserved Ratio Impaired Spirometry in Relationship to Cardiovascular Outcomes: A Large Prospective Cohort Study

BACKGROUND

Preserved ratio impaired spirometry (PRISm) findings are a heterogeneous condition characterized by a normal FEV₁ to FVC ratio with underlying impairment of pulmonary function. Data relating to the association of baseline and trajectories of PRISm findings with diverse cardiovascular outcomes are sparse.

RESEARCH QUESTION

How do baseline and trajectories of PRISm findings impact subsequent cardiovascular events?

STUDY DESIGN AND METHODS

In the UK Biobank cohort study, we included participants free of cardiovascular disease (CVD) with spirometry (FEV₁ and FVC values) at baseline (2006-2010). Participants with baseline spirometry and follow-up spirometry (2014-2020) were included in the lung function trajectory analysis. Cox proportional hazards multivariate regression was performed to evaluate the outcomes of major adverse cardiovascular events (MACEs), incident myocardial infarction (MI), stroke, heart failure (HF), and CVD mortality in association with lung function.

RESULTS

For baseline analysis (329,954 participants), the multivariate adjusted hazard ratios (HRs) for participants had PRISm findings (vs normal spirometry findings) were 1.26 (95% CI, 1.17-1.35) for MACE, 1.12 (95% CI, 1.01-1.25) for MI, 1.88 (95% CI, 1.72-2.05) for HF, 1.26 (95% CI, 1.13-1.40) for stroke, and 1.55 (95% CI, 1.37-1.76) for CVD mortality, respectively. A total of 22,781 participants underwent follow-up spirometry after an average of 8.9 years. Trajectory analysis showed that persistent PRISm findings (HR, 1.96; 95% CI, 1.24-3.09) and airflow obstruction (HR, 1.43; 95% CI, 1.00-2.04) was associated with a higher incidence of MACE vs consistently normal lung function. Compared with persistent PRISm findings, changing from PRISm to normal spirometry findings was associated with a lower incidence of MACE (HR, 0.42; 95% CI, 0.19-0.99).

INTERPRETATION

Individuals with baseline or persistent PRISm findings were at a higher risk of diverse cardiovascular outcomes even after adjusting for a wide range of confounding factors. However, individuals who transitioned from PRISm to normal findings showed a similar cardiovascular risk as those with normal lung function.

Preserved ratio impaired spirometry with or without restrictive spirometric abnormality

Preserved ratio impaired spirometry (PRISm) is defined by reduced FEV₁ with a preserved FEV₁/FVC ratio; some individuals with PRISm can also have restrictive ventilatory abnormality. The aim of this study was to clarify clinical features of restrictive and non-restrictive PRISm. In total, 11,246 participants (mean, 49.1 years; range, 35-65 years) from five healthcare centres were included in this study. We evaluated baseline characteristics of participants with restrictive PRISm (FEV₁/FVC ≥ 0.7, FEV₁ < 80% and FVC < 80%) and non-restrictive PRISm (FEV₁/FVC ≥ 0.7, FEV₁ < 80% and FVC ≥ 80%), and airflow obstruction (FEV₁/FVC < 0.7). We examined the longitudinal risk of developing airflow obstruction by comparing spirometry results at baseline and 5 years post-baseline among 2141 participants. Multivariate analysis demonstrated that a history of asthma or smoking could constitute an independent risk factor for non-restrictive PRISm, and that non-restrictive PRISm was independently associated with the risk of developing airflow obstruction. In contrast, female sex, advanced age, and high BMI, but not history of asthma or smoking, were risk factors for restrictive PRISm. Restrictive PRISm was not associated with the development of airflow obstruction. In conclusion, our results indicate that PRISm can be categorized according to the presence or absence of restrictive abnormality. Non-restrictive PRISm, which does not meet the conventional criteria of obstructive and restrictive ventilatory abnormalities, may be a precursor of chronic obstructive pulmonary disease and merits increased monitoring.

Plasticity of Individual Lung Function States from Childhood to Adulthood

Rationale: Recent evidence highlights the importance of optimal lung development during childhood for health throughout life. Objectives: To explore the plasticity of individual lung function states during childhood. Methods: Prebronchodilator FEV1 z-scores determined at age 8, 16, and 24 years in the Swedish population-based birth cohort BAMSE (Swedish abbreviation for Child [Barn], Allergy, Milieu, Stockholm, Epidemiological study) (N = 3,069) were used. An unbiased, data-driven dependent mixture model was applied to explore lung function states and individual state chains. Lung function catch-up was defined as participants moving from low or very low states to normal or high or very high states, and growth failure as moving from normal or high or very high states to low or very low states. At 24 years, we compared respiratory symptoms, small airway function (multiple-breath washout), and circulating inflammatory protein levels, by using proteomics, across states. Models were replicated in the independent Dutch population-based PIAMA (Prevention and Incidence of Asthma and Mite Allergy) cohort. Measurements and Main Results: Five lung function states were identified in BAMSE. Lung function catch-up and growth failure were observed in 74 (14.5%) BAMSE participants with low or very low states and 36 (2.4%) participants with normal or high or very high states, respectively. The occurrence of catch-up and growth failure was replicated in PIAMA. Early-life risk factors were cumulatively associated with the very low state, as well as with catch-up (inverse association) and growth failure. The very low state as well as growth failure were associated with respiratory symptoms, airflow limitation, and small airway dysfunction at adulthood. Proteomics identified IL-6 and CXCL10 (C-X-C motif chemokine 10) as potential biomarkers of impaired lung function development. Conclusions: Individual lung function states during childhood are plastic, including catch-up and growth failure.

Image Phenotyping of Preterm-Born Children Using Hyperpolarized 129Xe Lung Magnetic Resonance Imaging and Multiple-Breath Washout

Rationale: Preterm birth is associated with low lung function in childhood, but little is known about the lung microstructure in childhood. Objectives: We assessed the differential associations between the historical diagnosis of bronchopulmonary dysplasia (BPD) and current lung function phenotypes on lung ventilation and microstructure in preterm-born children using hyperpolarized 129Xe ventilation and diffusion-weighted magnetic resonance imaging (MRI) and multiple-breath washout (MBW). Methods: Data were available from 63 children (aged 9-13 yr), including 44 born preterm (⩽34 weeks' gestation) and 19 term-born control subjects (⩾37 weeks' gestation). Preterm-born children were classified, using spirometry, as prematurity-associated obstructive lung disease (POLD; FEV1 < lower limit of normal [LLN] and FEV1/FVC < LLN), prematurity-associated preserved ratio of impaired spirometry (FEV1 < LLN and FEV1/FVC ⩾ LLN), preterm-(FEV1 ⩾ LLN) and term-born control subjects, and those with and without BPD. Ventilation heterogeneity metrics were derived from 129Xe ventilation MRI and SF6 MBW. Alveolar microstructural dimensions were derived from 129Xe diffusion-weighted MRI. Measurements and Main Results: 129Xe ventilation defect percentage and ventilation heterogeneity index were significantly increased in preterm-born children with POLD. In contrast, mean 129Xe apparent diffusion coefficient, 129Xe apparent diffusion coefficient interquartile range, and 129Xe mean alveolar dimension interquartile range were significantly increased in preterm-born children with BPD, suggesting changes of alveolar dimensions. MBW metrics were all significantly increased in the POLD group compared with preterm- and term-born control subjects. Linear regression confirmed the differential effects of obstructive disease on ventilation defects and BPD on lung microstructure. Conclusion: We show that ventilation abnormalities are associated with POLD, and BPD in infancy is associated with abnormal lung microstructure.

The Prognostic Performance of Lung Diffusing Capacity in Preserved Ratio Impaired Spirometry: An Observational Cohort Study

Purpose

Similar to chronic obstructive pulmonary disease (COPD), the diffusing capacity of the lung (D_LCO) might be decreased and associated with poor prognosis in preserved ratio impaired spirometry (PRISm), a clinical entity as a prodromal phase of COPD. The aims of the present study were to evaluate the distributions of D_LCO and to assess the association between D_LCO and mortality among subjects with PRISm.

Patients and Methods

We conducted an observational cohort study at the National Hospital Organization Fukuoka National Hospital. We classified the 899 patients ≥ 40 years of age with an assessment of D_LCO into five groups based on spirometry: preserved spirometry, PRISm, mild COPD, moderate COPD, and severe/very severe COPD. The prevalence of low D_LCO (< 80% per predicted) was compared among the five groups. Using PRISm patients with follow-up data, we further investigated the association of low D_LCO with all-cause mortality.

Results

The prevalence of low D_LCO in the PRISm group (58.8%) was significantly higher than that in the preserved-spirometry group (21.8%), the mild-COPD group (23.5%), and the moderate-COPD group (36.0%) (all P < 0.01), and it was comparable to that in the severe/very severe-COPD group (63.2%). The results remained unchanged after adjusting for potential confounders. Among the PRISm subjects, the overall survival rate was significantly lower in the low-D_LCO group than in the preserved-D_LCO group (P < 0.01). The multivariable-adjusted hazard ratio (HR) for all-cause mortality was significantly higher in the low-D_LCO group than in the preserved-D_LCO group (HR = 10.10 (95% confidence interval 2.33–43.89)).

Conclusion

Diffusing capacity was more impaired in PRISm subjects than in those with preserved spirometry or mild to moderate COPD. Regarding PRISm, low D_LCO was a significant risk factor for all-cause mortality. Clinicians should assess D_LCO in the management of PRISm to predict the future risk of overall death.

The Relationship Between BMI and Lung Function in Populations with Different Characteristics: A Cross-Sectional Study Based on the Enjoying Breathing Program in China

Purpose

To analyze the relationship between body mass index (BMI) and lung function, which may help optimize the screening and management process for chronic obstructive pulmonary disease (COPD) in the early stages.

Patients and Methods

In this cross-sectional study using data from the Enjoying Breathing Program in China, participants were divided into two groups according to COPD Screening Questionnaire (COPD-SQ) scores (at risk and not at risk of COPD) and three groups based on lung function (normal lung function, preserved ratio impaired spirometry [PRISm], and obstructive lung function).

Results

A total of 32,033 subjects were enrolled in the current analysis. First, in people at risk of COPD, overweight and obese participants had better forced expiratory volume in one second (FEV1; overweight: 0.33 liters (l), 95% confidence interval [CI]: 0.27 to 0.38; obesity: 0.31 L, 95% CI: 0.22 to 0.39) values than the normal BMI group. Second, among people with PRISm, underweight participants had a lower FEV1 (−0.56 L, 95% CI: −0.86 to −0.26) and forced vital capacity (FVC; −0.33 L, 95% CI: −0.55 to −0.11) than participants with a normal weight, and obese participants had a higher FEV1 (0.22 L, 95% CI: 0.02 to 0.42) and FVC (0.16 L, 95% CI: 0.02 to 0.30) than participants with a normal weight. Taking normal BMI as the reference group, lower FEV1 (−0.80 L, 95% CI: −0.97 to −0.63) and FVC (−0.53 L, 95% CI: −0.64 to −0.42) were found in underweight participants with obstructive spirometry, and better FEV1 (obesity: 0.26 L, 95% CI: 0.12 to 0.40) was found in obese participants with obstructive spirometry.

Conclusion

Being underweight and severely obese are associated with reduced lung function. Slight obesity was shown to be a protective factor for lung function in people at risk of COPD and those with PRISm.

Clinical relevance of multiple confirmed preserved ratio impaired spirometry cases in adults

BACKGROUND

Preserved ratio impaired spirometry (PRISm) is a common spirometry finding, but its heterogeneous manifestations and frequent transitions to airflow limitation (AFL), chronic obstructive pulmonary disease, or normal spirometry hinder establishing an appropriate management strategy. This study examined whether transition to AFL and baseline comorbidities are more frequent in subjects with definite PRISm (PRISm confirmed on both current and past two spirometry tests) versus incident PRISm (PRISm confirmed only on a current test with past normal spirometry records) than in normal spirometry.

METHODS

Archived medical check-up data of subjects aged ≥40 years (n = 10828) with two past spirometry records, in a Japanese hospital, were cross-sectionally analyzed. Among them, data from those with follow-up spirometry after three years (n = 6467) were used to evaluate transition to AFL. PRISm was defined as forced volume in 1 s (FEV₁)/forced vital capacity ≥0.7 and % predicted FEV₁ < 80%.

RESULTS

Overall PRISm prevalence was 6.5%. In multivariable models adjusted for age, sex, smoking status, and body mass index, definite PRISm (n = 290), but not incident PRISm (n = 183), was associated with elevated hemoglobin A1c and C-reactive protein levels, and higher rates of asthma, hypertension, hyperlipidemia, and diabetes than was consistent normal spirometry (n = 9694). The transition to AFL after three years was more frequent in definite PRISm, but not incident PRISm, than in normal spirometry (adjusted hazard ratio [95% confidence interval] = 6.21 [3.42-10.71] and 1.45 [0.23-4.73], respectively).

CONCLUSIONS

Multiple confirmed PRISm on past and baseline spirometry is closely associated with metabolic syndrome factors, asthma history, and future AFL development.

Geographical Differences and Temporal Improvements in Forced Expiratory Volume in 1 Second of Preterm-Born Children: A Systematic Review and Meta-analysis

Importance

Although preterm birth is associated with later deficits in lung function, there is a paucity of information on geographical differences and whether improvements occur over time, especially after surfactant was introduced.

Objective

To determine deficits in percentage predicted forced expiratory volume in 1 second (%FEV1) in preterm-born study participants, including those with bronchopulmonary dysplasia (BPD) in infancy, when compared with term-born control groups.

Data Sources

Eight databases searched up to December 2021.

Study Selection

Studies reporting spirometry for preterm-born participants with or without a term-born control group were identified.

Data Extraction and Synthesis

Data were extracted and quality assessed by 1 reviewer and checked by another. Data were pooled using random-effects models and analyzed using Review Manager and the R metafor package.

Main Outcomes and Measures

Deficits in %FEV1 between preterm-born and term groups. Associations between deficits in %FEV1 and year of birth, age, introduction of surfactant therapy, and geographical region of birth and residence were also assessed.

Results

From 16 856 titles, 685 full articles were screened: 86 with and without term-born control groups were included. Fifty studies with term controls were combined with the 36 studies from our previous systematic review, including 7094 preterm-born and 17 700 term-born participants. Of these studies, 45 included preterm-born children without BPD, 29 reported on BPD28 (supplemental oxygen dependency at 28 days), 26 reported on BPD36 (supplemental oxygen dependency at 36 weeks' postmenstrual age), and 86 included preterm-born participants. Compared with the term-born group, the group of all preterm-born participants (all preterm) had deficits of %FEV1 of -9.2%; those without BPD had deficits of -5.8%, and those with BPD had deficits of approximately -16% regardless of whether they had BPD28 or BPD36. As year of birth increased, there was a statistically significant narrowing of the difference in mean %FEV1 between the preterm- and term-born groups for the all preterm group and the 3 BPD groups but not for the preterm-born group without BPD. For the all BPD group, when compared with Scandinavia, North America and western Europe had deficits of -5.5% (95% CI, -10.7 to -0.3; P = .04) and -4.1% (95% CI, -8.8 to 0.5; P = .08), respectively.

Conclusions and Relevance

Values for the measure %FEV1 were reduced in preterm-born survivors. There were improvements in %FEV1 over recent years, but geographical region had an association with later %FEV1 for the BPD groups.

Impaired exercise outcomes with significant bronchodilator responsiveness in children with prematurity-associated obstructive lung disease

INTRODUCTION

Preterm-born children have their normal in-utero lung development interrupted, thus are at risk of short- and long-term lung disease. Spirometry and exercise capacity impairments have been regularly reported in preterm-born children especially those who developed chronic lung disease of prematurity (CLD) in infancy. However, specific phenotypes may be differentially associated with exercise capacity. We investigated exercise capacity associated with prematurity-associated obstructive (POLD) or prematurity-associated preserved ratio of impaired spirometry (pPRISm) when compared to preterm- and term-controls with normal lung function.

MATERIALS AND METHODS

Preterm- and term-born children identified through home screening underwent in-depth lung function and cardiorespiratory exercise testing, including administration of postexercise bronchodilator, as part of the Respiratory Health Outcomes in Neonates (RHiNO) study.

RESULTS

From 241 invited children, aged 7-12 years, 202 underwent exercise testing including 18 children with POLD (percent predicted (%)FEV₁ and FEV₁ /FVC < LLN); 12 pPRISm (%FEV₁  < LLN and FEV₁ /FVC ≥ LLN), 106 preterm-controls (PT_c , %FEV₁  ≥ LLN) and 66 term-controls (T_c , %FEV₁  > 90%). POLD children had reduced relative workload, peak O₂ uptake, CO₂ production, and minute ventilation compared to T_c , and used a greater proportion of their breathing reserve compared to both control groups. pPRISm and PT_c children also had lower O₂ uptake compared to T_c . POLD children had the greatest response to postexercise bronchodilator, improving their %FEV₁ by 19.4% (vs 6.3%, 6% 6.3% in pPRISm PT_c, T_c , respectively; p < .001).

CONCLUSION

Preterm-born children with obstructive airway disease had the greatest impairment in exercise capacity, and significantly greater response to postexercise bronchodilators. These classifications can be used to guide treatment in children with POLD.

Prognosis of Patients with Chronic Obstructive Pulmonary Disease Not Eligible for Major Clinical Trials

Rationale: Randomized controlled trials only include a subset of patients with chronic obstructive pulmonary disease (COPD) fulfilling strict inclusion criteria. Thus, most patients with COPD in a real-world setting do not have the necessary evidence to support treatment effectiveness. Objectives: To test the hypotheses that most individuals with COPD in the general population are not represented in major clinical trials despite clinically significant disease with exacerbations and early death. Methods: In 105,630 adults from a Danish contemporary population-based cohort, we defined COPD as age 40 or more years, chronic respiratory symptoms, history of smoking exposure, and airflow limitation with FEV₁/FVC < 0.70. Outcomes included acute exacerbations and all-cause mortality. Symptomatic smokers without COPD were used as a reference group. Measurements and Main Results: Of all, 7,516 (7%) and 16,079 (15%) were symptomatic smokers with and without COPD. Only 44% of those with COPD were eligible for major clinical trials when applying FEV₁ < 80% predicted, smoking history of 10 or more pack-years, and no comorbid asthma as common inclusion criteria. During the median 8.9 years of follow-up, we observed 2,130 acute exacerbations and 3,973 deaths in symptomatic smokers. Compared with symptomatic smokers without COPD, multivariable-adjusted hazard ratios for exacerbations were 7.45 (95% confidence interval, 5.41-10.3) and 29.0 (21.1-39.8) in those with COPD, respectively, excluded and eligible for clinical trials. Corresponding hazard ratios for all-cause mortality were 1.21 (1.11-1.31) and 1.67 (1.54-1.81), respectively. Conclusions: More than half of individuals with COPD in the general population are excluded from major clinical trials; however, these individuals have a clinically significant disease with exacerbations and early death compared with symptomatic smokers without COPD.

Plasma immunoglobulin E and risk of exacerbation and mortality in chronic obstructive pulmonary disease: A contemporary population-based cohort

BACKGROUND

Novel biomarkers and targeted treatments are needed for patients with chronic obstructive pulmonary disease (COPD).

OBJECTIVE

To test the hypothesis that high plasma immunoglobulin (Ig)E concentrations associate with increased risk of exacerbation and mortality in individuals with COPD in the general population.

METHODS

Among 46,598 adults in the Copenhagen General Population Study, we included 1559 with COPD, defined as forced expiratory volume in 1 second/forced vital capacity < 0.70 and forced expiratory volume in 1 second < 80% predicted in individuals aged ≥ 40 years with chronic respiratory symptoms and smoking exposure ≥ 10 pack-years, and without asthma. We assessed risk of future severe exacerbation and all-cause mortality according to baseline plasma IgE ≥ 76 IU/mL, a clinical cutoff for omalizumab treatment in severe asthma.

RESULTS

During 14 years of follow-up (median, 6.9; interquartile range, 3.4), we recorded 224 severe exacerbations and 434 deaths in 1559 individuals with COPD. Individuals with COPD with IgE ≥ 76 IU/mL vs those with < 76 IU/mL had a multivariable adjusted hazard ratio (HR) of 1.43 (95% confidence interval, 1.07-1.89) for severe exacerbation and 1.30 (1.05-1.62) for all-cause mortality. Compared with individuals with IgE < 76 IU/mL and blood eosinophils < 300 cells/µL, the multivariable adjusted HR for severe exacerbation was 1.12 (0.76-1.67) for those with IgE < 76 IU/mL and blood eosinophils ≥ 300 cells/µL, 1.62 (1.17-2.24) for IgE ≥ 76 IU/mL and blood eosinophils < 300 cells/µL, and 1.06 (0.63-1.77) for those with IgE ≥ 76 IU/mL and blood eosinophils ≥ 300 cells/µL. Corresponding HRs for all-cause mortality were 1.27 (0.99-1.63), 1.47 (1.14-1.88), and 1.17 (0.83-1.64), respectively.

CONCLUSION

High plasma IgE was associated with an increased risk of severe exacerbation and all-cause mortality in individuals with COPD in the general population, independent of blood eosinophils.

ERS/ATS technical standard on interpretive strategies for routine lung function tests

BACKGROUND

Appropriate interpretation of pulmonary function tests (PFTs) involves the classification of observed values as within/outside the normal range based on a reference population of healthy individuals, integrating knowledge of physiological determinants of test results into functional classifications and integrating patterns with other clinical data to estimate prognosis. In 2005, the American Thoracic Society (ATS) and European Respiratory Society (ERS) jointly adopted technical standards for the interpretation of PFTs. We aimed to update the 2005 recommendations and incorporate evidence from recent literature to establish new standards for PFT interpretation.

METHODS

This technical standards document was developed by an international joint Task Force, appointed by the ERS/ATS with multidisciplinary expertise in conducting and interpreting PFTs and developing international standards. A comprehensive literature review was conducted and published evidence was reviewed.

RESULTS

Recommendations for the choice of reference equations and limits of normal of the healthy population to identify individuals with unusually low or high results are discussed. Interpretation strategies for bronchodilator responsiveness testing, limits of natural changes over time and severity are also updated. Interpretation of measurements made by spirometry, lung volumes and gas transfer are described as they relate to underlying pathophysiology with updated classification protocols of common impairments.

CONCLUSIONS

Interpretation of PFTs must be complemented with clinical expertise and consideration of the inherent biological variability of the test and the uncertainty of the test result to ensure appropriate interpretation of an individual's lung function measurements.

Clinical and Immunological Markers of Pulmonary Impairment among People with HIV(PWH) in India

Background

Despite antiretroviral therapy, chronic lung diseases remain an important source of morbidity and mortality in people with HIV (PWH). We sought to identify clinical and immunological markers of pulmonary impairment among PWH in India.

Methods

Two hundred ten adult PWH receiving antiretroviral therapy (ART) were prospectively evaluated for 3 years. Plasma concentrations of interleukin (IL)-6, IL-10, tumor necrosis factor alpha, D-dimer, C-reactive protein, soluble (s)CD14, and sCD163 were measured at enrollment. We used multivariable linear and logistic regression to measure the association of baseline and time-varying clinical and immunological variables with spirometry-defined chronic obstructive pulmonary disease (COPD), restrictive spirometry pattern (RSP), preserved ratio impaired spirometry (PRISm), forced expiratory volume in 1 second (FEV1), and forced vital capacity (FVC) during the third year of follow-up.

Results

After adjusting confounders, females were 7 times more likely to have RSP (95% CI, 2.81 to 17.62; P < .001) and 22 times more likely to have PRISm (95% CI, 7.42 to 69.92; P < .001) compared with men. Higher IL-6 concentrations were associated with lower FEV1 z-scores (β, −0.14 per log-higher; 95% CI, −0.29 to 0.008; P = .06) and higher odds of COPD (adjusted odds ratio [aOR], 2.66 per log-higher; 95% CI, 1.16 to 6.09; P = .02). Higher D-dimer concentrations were associated with lower FVC z-scores (β, −0.40 per log-higher; 95% CI, −0.78 to −0.01; P = .04). Conversely, higher IL-10 concentrations were associated with lower odds of PRISm (aOR, 0.76 per log-higher; 95% CI, 0.59 to 0.99; P = .04).

Conclusions

Female sex, higher concentrations of IL-6 and D-dimer, and lower concentrations of IL-10 were associated with pulmonary impairment in adult PWH receiving ART in India.

Association Between Preserved Ratio Impaired Spirometry and Clinical Outcomes in US Adults

Importance

Chronic lung diseases are a leading cause of morbidity and mortality. Unlike chronic obstructive pulmonary disease, clinical outcomes associated with proportional reductions in expiratory lung volumes without obstruction, otherwise known as preserved ratio impaired spirometry (PRISm), are poorly understood.

Objective

To examine the prevalence, correlates, and clinical outcomes associated with PRISm in US adults.

Design, Setting, and Participants

The National Heart, Lung, and Blood Institute (NHLBI) Pooled Cohorts Study was a retrospective study with harmonized pooled data from 9 US general population-based cohorts (enrollment, 65 251 participants aged 18 to 102 years of whom 53 701 participants had valid baseline lung function) conducted from 1971-2011 (final follow-up, December 2018).

Exposures

Participants were categorized into mutually exclusive groups by baseline lung function. PRISm was defined as the ratio of forced expiratory volume in the first second to forced vital capacity (FEV1:FVC) greater than or equal to 0.70 and FEV1 less than 80% predicted; obstructive spirometry FEV1:FVC ratio of less than 0.70; and normal spirometry FEV1:FVC ratio greater than or equal to 0.7 and FEV1 greater than or equal to 80% predicted.

Main Outcomes and Measures

Main outcomes were all-cause mortality, respiratory-related mortality, coronary heart disease (CHD)-related mortality, respiratory-related events (hospitalizations and mortality), and CHD-related events (hospitalizations and mortality) classified by adjudication or validated administrative criteria. Absolute risks were adjusted for age and smoking status. Poisson and Cox proportional hazards models comparing PRISm vs normal spirometry were adjusted for age, sex, race and ethnicity, education, body mass index, smoking status, cohort, and comorbidities.

Results

Among all participants (mean [SD] age, 53.2 [15.8] years, 56.4% women, 48.5% never-smokers), 4582 (8.5%) had PRISm. The presence of PRISm relative to normal spirometry was significantly associated with obesity (prevalence, 48.3% vs 31.4%; prevalence ratio [PR], 1.68 [95% CI, 1.55-1.82]), underweight (prevalence, 1.4% vs 1.0%; PR, 2.20 [95% CI, 1.72-2.82]), female sex (prevalence, 60.3% vs 59.0%; PR, 1.07 [95% CI, 1.01-1.13]), and current smoking (prevalence, 25.2% vs 17.5%; PR, 1.33 [95% CI, 1.22-1.45]). PRISm, compared with normal spirometry, was significantly associated with greater all-cause mortality (29.6/1000 person-years vs 18.0/1000 person-years; difference, 11.6/1000 person-years [95% CI, 10.0-13.1]; adjusted hazard ratio [HR], 1.50 [95% CI, 1.42-1.59]), respiratory-related mortality (2.1/1000 person-years vs 1.0/1000 person-years; difference, 1.1/1000 person-years [95% CI, 0.7-1.6]; adjusted HR, 1.95 [95% CI, 1.54-2.48]), CHD-related mortality (5.4/1000 person-years vs 2.6/1000 person-years; difference, 2.7/1000 person-years [95% CI, 2.1-3.4]; adjusted HR, 1.55 [95% CI, 1.36-1.77]), respiratory-related events (12.2/1000 person-years vs 6.0/1000 person-years; difference, 6.2/1000 person-years [95% CI, 4.9-7.5]; adjusted HR, 1.90 [95% CI, 1.69-2.14]), and CHD-related events (11.7/1000 person-years vs 7.0/1000 person-years; difference, 4.7/1000 person-years [95% CI, 3.7-5.8]; adjusted HR, 1.30 [95% CI, 1.18-1.42]).

Conclusions and Relevance

In a large, population-based sample of US adults, baseline PRISm, compared with normal spirometry, was associated with a small but statistically significant increased risk for mortality and adverse cardiovascular and respiratory outcomes. Further research is needed to explore whether this association is causal.