Reference ranges for spirometry across all ages: a new approach

Dyspnea in Community-Dwelling Older Persons: A Multifactorial Geriatric Health Condition

OBJECTIVES

To evaluate the associations between a broad array of cardiorespiratory and noncardiorespiratory impairments and dyspnea in older persons.

DESIGN

Cross-sectional.

SETTING

Cardiovascular Health Study.

PARTICIPANTS

Community-dwelling persons (N = 4,413; mean age 72.6, 57.1% female, 4.5% African American, 27.2% <high school education, 54.7% ever-smokers).

MEASUREMENTS

Dyspnea severity (moderate to severe defined as American Thoracic Society Grade ≥2) and several impairments, including those established using spirometry (forced expiratory volume in 1 second (FEV₁ )), maximal inspiratory pressure (respiratory muscle strength), echocardiography, ankle-brachial index, blood pressure, whole-body muscle mass (bioelectrical impedance), single chair stand (lower extremity function), grip strength, serum hemoglobin and creatinine, Center for Epidemiologic Studies Depression Scale (CES-D), Mini-Mental State Examination, medication use, and body mass index (BMI).

RESULTS

In a multivariable logistic regression model, impairments that had strong associations with moderate to severe dyspnea were FEV₁ less than the lower limit of normal (adjusted odds ratio (aOR) = 2.88, 95% confidence interval (CI) = 2.37-3.49), left ventricular ejection fraction less than 45% (aOR = 2.12, 95% CI = 1.43, 3.16), unable to perform a single chair stand (aOR = 2.10, 95% CI = 1.61-2.73), depressive symptoms (CES-D score ≥16; aOR = 2.02, 95% CI = 1.26-3.23), and obesity (BMI ≥30; aOR = 2.07, 95% CI = 1.67-2.55). Impairments with modest but still statistically significant associations with moderate to severe dyspnea included respiratory muscle weakness, diastolic cardiac dysfunction, grip weakness, anxiety symptoms, and use of cardiovascular and psychoactive medications (aORs = 1.31-1.71).

CONCLUSION

In community-dwelling older persons, several cardiorespiratory and noncardiorespiratory impairments were significantly associated with moderate to severe dyspnea, akin to a multifactorial geriatric health condition.

Phenotype of Spirometric Impairment in an Aging Population

RATIONALE

The Global Lung Initiative (GLI) provides age-appropriate criteria for establishing spirometric impairment, including mild, moderate, and severe chronic obstructive pulmonary disease (COPD) and restrictive pattern, but its association with respiratory-related phenotypes has not been evaluated.

OBJECTIVES

To evaluate respiratory-related phenotypes in GLI-defined spirometric impairment.

METHODS

In COPDGene (N = 10,131 patients; age range, 45-81 yr; average smoking history, 44.3 pack-years), we evaluated spirometry, dyspnea (modified Medical Research Council grade, ≥2), poor respiratory health-related quality of life (St. George's Respiratory Questionnaire total score, ≥25), poor exercise performance (6-minute-walk distance, <391 m), bronchodilator reversibility (FEV1 change, >12% and ≥200 ml), and computed tomography-diagnosed emphysema and gas trapping (>5% and >15% of lung, respectively).

MEASUREMENTS AND MAIN RESULTS

GLI established normal spirometry in 5,100 patients (50.3%), mild COPD in 669 (6.6%), moderate COPD in 865 (8.5%), severe COPD in 2,522 (24.9%), and restrictive pattern in 975 (9.6%). Relative to normal spirometry, graded associations with respiratory-related phenotypes were found for mild, moderate, and severe COPD, with respective adjusted odds ratios (95% confidence intervals) as follows: dyspnea-1.31 (1.10-1.56), 2.20 (1.81-2.68), and 10.73 (8.04-14.33); poor respiratory health-related quality of life-1.49 (1.28-1.75), 2.69 (2.08-3.47), and 14.61 (10.09-21.17); poor exercise performance-1.11 (0.94-1.31), 1.58 (1.33-1.88), and 4.58 (3.42-6.12); bronchodilator reversibility-2.76 (2.24-3.40), 5.18 (4.29-6.27), and 6.21 (5.06-7.62); emphysema-4.86 (3.16-7.47), 6.41 (4.09-10.05), and 17.79 (10.79-29.32); and gas trapping-3.92 (3.12-4.93), 5.20 (3.82-7.07), and 16.28 (9.71-27.30). Restrictive pattern was also associated with multiple respiratory-related phenotypes at a level similar to moderate COPD, but it was otherwise not associated with emphysema (0.89 [0.60-1.32]) or gas trapping (1.15 [0.92-1.42]).

CONCLUSIONS

GLI-defined spirometric impairment establishes clinically meaningful respiratory disease, as validated by graded associations with respiratory-related phenotypes.

Effect of Structured Physical Activity on Respiratory Outcomes in Sedentary Elderly Adults with Mobility Limitations

OBJECTIVES

To evaluate the effect of structured physical activity on respiratory outcomes in community-dwelling elderly adults with mobility limitations.

DESIGN

Multicenter, randomized trial of physical activity vs health education, with respiratory variables prespecified as tertiary outcomes over an intervention period of 24-42 months. Physical activity included walking (goal of 150 min/week) and strength, flexibility, and balance training. Health education included workshops on topics relevant to older adults and upper extremity stretching exercises.

SETTING

Lifestyle Interventions and Independence in Elders (LIFE) Study.

PARTICIPANTS

Community-dwelling persons aged 70-89 with Short Physical Performance Battery scores less than 10 (N = 1,635).

MEASUREMENTS

Dyspnea severity (defined as moderate to severe according to a Borg index >2 immediately after a 400-m walk), forced expiratory volume in 1 second (FEV1) (<lower limit of normal (LLN) defined low breathing capacity), and maximal inspiratory pressure (MIP) (<LLN defined respiratory muscle weakness) were assessed at baseline and 6, 18, and 30 months. Hospitalization for exacerbation of obstructive airways disease (EOAD) and pneumonia was also ascertained over the 42-month follow-up period.

RESULTS

The randomized groups were similar in baseline demographics, including mean age (79) and sex (67% female). The effect of physical activity on dyspnea severity, FEV1, and MIP was no different from that of health education but was associated with higher likelihood of respiratory hospitalization, significantly for EOAD (hazard ratio (HR) = 2.34, 95% confidence interval (CI) = 1.19-4.61, P = .01) and marginally for pneumonia (HR = 1.54, 95% CI = 0.98-2.42, P = .06).

CONCLUSION

In older persons with mobility limitations, physical activity was associated with higher likelihood of respiratory hospitalization than health education, but differences in dyspnea severity, FEV1, and MIP did not accompany this effect-indicating that higher hospital use could be attributable to greater participant contact.

Pulmonary function and fitness years after treatment for hypersensitivity pneumonitis during childhood

BACKGROUND

Hypersensitivity pneumonitis (HP) is an immune-mediated diffuse lung disease. Significant improvement in lung function and diffusing capacity after treatment was previously demonstrated, while long-term data focusing specifically on peripheral airway impairment and peak oxygen uptake (fitness) are lacking. Hence, the aim of this study was to conduct a comprehensive study to determine the stability of pulmonary function and fitness in patients previously diagnosed with HP.

METHODS

We performed a cross-sectional follow-up study with inclusion of longitudinal data if available in patients previously diagnosed with biopsy and high-resolution computed tomography-verified HP during childhood. We performed multiple breath wash-out (LCI2.5 ), spirometry (FEV1 ), bronchiodilator responsiveness test, diffusing capacity (DLCO and DLCO /VA ), body-plethysmography (TLC), and peak oxygen uptake (VO2peak ). St. George Respiratory Questionnaire was used as a measure of respiratory quality of life.

RESULTS

Twenty two patients were assessed. LCI2.5 was abnormal in 47.4% compared to abnormal FEV1 in only 9.1% and without significant bronchiodilator responsiveness. DLCO and TLC were abnormal in 40.9 and 13.6%, respectively, while DLCO /VA was within normal range. Only 11.1% demonstrated abnormal VO2peak . All longitudinally assessed outcomes remained unchanged between end of treatment and time of follow up.

CONCLUSIONS

A large proportion of patients previously diagnosed with HP had abnormal LCI2.5 in contrast to normal spirometry. Spirometric outcomes, TLC, and diffusing capacity were persistently slightly reduced, but stable, and VO2peak was excellent at time of follow-up. Long-term prognosis in children with HP appears favorable although persistent peripheral airway involvement of unknown clinical significance was demonstrated in almost half of the patients. Pediatr Pulmonol. 2016;51:830-837. © 2015 Wiley Periodicals, Inc.

Lung Function Monitoring; A Randomized Agreement Study

Objective:

To determine the agreement between devices and repeatability within devices of the forced expiratory volume in 1 s (FEV₁), forced vital capacity (FVC), peak expiratory flow (PEF) and forced expiratory flow at 50% of FVC (FEF₅₀) values measured using the four spirometers included in the study.

Methods:

50 (24 women) participants (20-64 years of age) completed maximum forced expiratory flow manoeuvres and measurements were performed using the following devices: MasterScreen, SensorMedics, Oxycon Pro and SpiroUSB. The order of the instruments tested was randomized and blinded for both the participants and the technicians. Re-testing was conducted on a following day within 72 hours at the same time of the day.

Results:

The devices which obtained the most comparable values for all lung function variables were SensorMedics and Oxycon Pro, and MasterScreen and SpiroUSB. For FEV₁, mean difference was 0.04 L (95% confidence interval; -0.05, 0.14) and 0.00 L (-0.06, 0.06), respectively. When using the criterion of FVC and FEV₁ ≤ 0.150 L for acceptable repeatability, 67% of the comparisons of the measured lung function values obtained by the four devices were acceptable. Overall, Oxycon Pro obtained most frequently values of the lung function variables with highest precision as indicated by the coefficients of repeatability (CR), followed by MasterScreen, SensorMedics and SpiroUSB (e.g. min-max CR for FEV₁; 0.27-0.46).

Conclusion:

The present study confirms that measurements obtained by the same device at different times can be compared; however, measured lung function values may differ depending on spirometers used.

Study protocol, rationale and recruitment in a European multi-centre randomized controlled trial to determine the efficacy and safety of azithromycin maintenance therapy for 6 months in primary ciliary dyskinesia

Background

Clinical management of primary ciliary dyskinesia (PCD) respiratory disease is currently based on improving mucociliary clearance and controlling respiratory infections, through the administration of antibiotics. Treatment practices in PCD are largely extrapolated from more common chronic respiratory disorders, particularly cystic fibrosis, but no randomized controlled trials (RCT) have ever evaluated efficacy and safety of any pharmacotherapeutics used in the treatment of PCD. Maintenance therapy, with the macrolide antibiotic azithromycin, is currently widely used in chronic respiratory diseases including PCD. In addition to its antibacterial properties, azithromycin is considered to have beneficial anti-inflammatory and anti-quorum-sensing properties.

The aim of this study is to determine the efficacy of azithromycin maintenance therapy for 6 months on respiratory exacerbations in PCD. The secondary objectives are to evaluate the efficacy of azithromycin on lung function, ventilation inhomogeneity, hearing impairment, and symptoms (respiratory, sinus, ears and hearing) measured on a PCD-specific health-related quality of life instrument, and to assess the safety of azithromycin maintenance therapy in PCD.

Methods

The BESTCILIA trial is a European multi-centre, double-blind, randomized, placebo-controlled, parallel group study. The intervention is tablets of azithromycin 250/500 mg according to body weight or placebo administered three times a week for 6 months. Subjects with a confirmed diagnosis of PCD, age 7–50 years, are eligible for inclusion. Chronic pulmonary infections with Gram-negative bacteria or any recent occurrence of non-tuberculous mycobacteria are exclusion criteria. The planned number of subjects to be included is 125. The trial has been approved by the Research Ethics Committees of the participating institutions.

Discussion

We present a study protocol of an ongoing RCT, evaluating for the first time, the efficacy and safety of a pharmacotherapeutic treatment for patients with PCD. The RCT evaluates azithromycin maintenance therapy, a drug already commonly prescribed in other chronic respiratory disorders. Furthermore, the trial will utilize the Lung clearance index and new, PCD-specific quality of life instruments as outcome measures for PCD. Recruitment is hampered by frequent occurrence of Pseudomonas aeruginosa infection, exacerbations at enrolment, and the patients’ perception of disease severity and necessity of additional management and treatment during trial participation.

Trial registration

EudraCT 2013-004664-58 (date of registration: 2014-04-08).

Use the Lower Limit of Normal, Not 80% Predicted, in Judging Eligibility for Lung Resection

BACKGROUND

Impaired lung function (LF) is a well-known risk factor for perioperative complications in patients qualified for lung resection surgery. The recent European guidelines recommend using values below 80% predicted as indicating abnormal LF rather than the lower limit of normal (LLN).

OBJECTIVES

To assess how the choice of a cut-off point (80% predicted vs. LLN at -1.645 SD) affects the incidence of functional disorders and postoperative complications in lung cancer patients referred for lung resection.

METHODS

Preoperative spirometry and the transfer factor for carbon monoxide (TL,CO) were retrospectively analysed in 851 consecutive lung cancer patients after resectional surgery.

RESULTS

Airway obstruction was diagnosed in 369 (43.4%), and a restrictive pattern in 41 patients (4.8%). The forced expiratory volume in 1 s (FEV1) or TL,CO was below the LLN in 503 patients (59.1%), whereas the FEV1 or TL,CO was <80% predicted in 620 patients (72.9%; χ2 test: p < 0.0001). In all, 117 out of 851 patients had LF indices <80% predicted but not below the LLN. Odds ratios (ORs) for perioperative complications were higher in patients with impaired LF indices defined as below the LLN (1.59, p = 0.0005) with the exception of large resections (>5 segments). In patients with test results above the LLN and <80% predicted, the OR for perioperative complications was not different (1.14, p = 0.5) from that in patients with normal LF.

CONCLUSIONS

LF impairments are common in candidates for lung resection. Using the LLN instead of 80% predicted diminishes the prevalence of respiratory impairment by 14% and allows for safe resectional surgery without additional function testing.

Comparison of NHANES III and ERS/GLI 12 for airway obstruction classification and severity

The diagnosis and severity categorisation of obstructive lung disease is determined using reference values. The American Thoracic Society/European Respiratory Society in 2005 recommended the National Health and Nutrition Examination Survey (NHANES) III spirometry prediction equations for patients in USA aged 8–80 years. The Global Lung Initiative 2012 (GLI 12) provided spirometry prediction equations for patients aged 3–95 years. Comparison of the NHANES III and GLI 12 prediction equations for diagnosing and categorising airway obstruction in patients in USA has not been made.

We aimed to quantify the differences between NHANES III and GLI 12 predicted values in Caucasians aged 18–95 years, using both mathematical simulation and clinical data. We compared predicted forced expiratory volume in 1 s (FEV1) and lower limit of normal (LLN) FEV1/forced vital capacity (FVC) % for NHANES III and GLI 12 prediction equations by applying both a simulation model and clinical spirometry data to quantify differences in the diagnosis and categorisation of airway obstruction.

Mathematical simulation revealed significant similarities and differences between prediction equations for both LLN FEV1/FVC % and predicted FEV1. There are significant differences when using GLI 12 and NHANES III to diagnose airway obstruction and severity in Caucasian patients aged 18–95 years.

Similarities and differences exist between NHANES III and GLI 12 for some age and height combinations. The differences in LLN FEV1/FVC % and predicted FEV1 are most prominent in older taller/shorter individuals. The magnitude of the differences can be large and may result in differences in clinical management.

Symptoms and lung function decline in a middle-aged cohort of males and females in Australia

BACKGROUND

The European Community Respiratory Health Survey is a major international study designed to assess lung health in adults. This Australian follow-up investigated changes in symptoms between sexes and the roles of asthma, smoking, age, sex, height, and change in body mass index (ΔBMI) on lung function decline (LFD), which is a major risk factor for chronic obstructive pulmonary disease (COPD).

METHODS

LFD was measured as the rate of decline over time in FEV1 (mL/year) (ΔFEV1) and FVC (ΔFVC) between 1993 and 2013. Multiple linear regression was used to estimate associations between risk factors and LFD, separately for males and females. Multiple logistic regression was used to assess sex differences and changes in respiratory symptoms over time.

RESULTS

In Melbourne, 318 subjects (53.8% females) participated. The prevalence of most respiratory symptoms had either remained relatively stable over 20 years or decreased (significantly so for wheeze). The exception was shortness of breath after activity, which had increased. Among the 262 subjects who completed spirometry, current smoking declined from 20.2% to 7.3%. Overall mean (± standard deviation) FEV1 declined by 23.1 (±17.1) and FVC by 22.9 (±20.2) mL/year. Predictors of ΔFEV1 in males were age, maternal smoking, and baseline FEV1; and in females they were age, ΔBMI, baseline FEV1, and pack-years in current smokers. Decline in FVC was predicted by baseline FVC, age, and ΔBMI in both sexes; however, baseline FVC predicted steeper decline in females than males.

CONCLUSION

Most respiratory symptoms remained stable or decreased over time in both sexes. Age, baseline lung function, and change in BMI were associated with the rate of decline in both sexes. However, obesity and personal smoking appear to put females at higher risk of LFD than males. Health promotion campaigns should particularly target females to prevent COPD.

Outcomes of Childhood Asthma and Wheezy Bronchitis. A 50-Year Cohort Study

RATIONALE

Cohort studies suggest that airflow obstruction is established early in life, manifests as childhood asthma and wheezy bronchitis, and continues into early adulthood. Although an association between childhood asthma and chronic obstructive pulmonary disease (COPD) in later life has been demonstrated, it is unclear if childhood wheezy bronchitis is associated with COPD.

OBJECTIVES

To investigate whether childhood wheezy bronchitis increases the risk of COPD in the seventh decade.

METHODS

A cohort of children recruited in 1964 at age 10 to 15 years, which was followed up in 1989, 1995, and 2001, was followed up again in 2014 when at age 60 to 65 years. Discrete time-to-event and linear mixed effects models were used.

MEASUREMENTS AND MAIN RESULTS

FEV1 and FVC were measured. COPD was defined as post-bronchodilator FEV1/FVC <0.7. Childhood wheezing phenotype was related to 1989, 1995, 2001, and 2014 spirometry data. Three hundred thirty subjects, mean age 61 years, were followed up: 38 with childhood asthma; 53 with childhood wheezy bronchitis; and 239 control subjects (of whom 57 developed adulthood-onset wheeze between ages 16 and 46 yr). In adjusted multivariate analyses, childhood asthma was associated with an increased risk of COPD (odds ratio, 6.37; 95% confidence interval, 3.73-10.94), as was childhood wheezy bronchitis (odd ratio 1.81; 95% confidence interval, 1.12-2.91). The COPD risk increased with childhood asthma, and wheezy bronchitis was associated with reduced FEV1 that was evident by the fifth decade and not an accelerated rate of FEV1 decline. In contrast, adulthood-onset wheeze was associated with accelerated FEV1 decline.

CONCLUSIONS

Childhood wheezy bronchitis and asthma are associated with an increased risk of COPD and reduced ventilatory function.

Factors associated with quality of life in children with asthma living in Scotland

INTRODUCTION

Asthma affects children's quality of life (QoL) but factors associated with QoL are not well understood. Our hypothesis was that there are factors linked to QoL which are amenable to treatment or environmental modification.

METHODS

QoL was ascertained in a study designed to link environmental exposures to asthma outcomes. Univariate and multivariate analysis were used to determine which factors are associated with QoL.

RESULTS

There were 553 children with asthma where QoL was determined, mean age 10.3 and 312 (58%) were boys. The median QoL score was 5.9 (interquartile range 4.6, 6.8). In the multivariate model, asthma severity (as evidenced by British Thoracic Society, BTS, treatment step), smoking exposure, socioeconomic status and rhinitis were associated with the QoL score. QoL score was reduced by (i) 30% [95% confidence interval 20, 39] for those on BTS step 4 compared to BTS step 1 treatment (ii) 11% [2, 19] for children with ≥ two resident smokers with reference to no resident smokers (iii) 3% [1, 5] for each quintile difference in deprivation compared to the most affluent and (iv) 9% [4, 14] for children with rhinitis compared to no rhinitis.

CONCLUSIONS

The QoL for children with asthma in the UK is generally good. Clinicians caring children with asthma should consider routinely asking about smoke exposure and hayfever symptoms in addition to assessing asthma control.

Pulmonary ventilation and micro-structural findings in congenital diaphragmatic hernia

BACKGROUND

With increasing survival of patients with more severe forms of congenital diaphragmatic hernia (CDH) and risk of long-term respiratory morbidity, studies on lung morphology are needed. We used hyperpolarised (3) He MRI and anatomical (1) H MRI in a cohort of young adult CDH patients to image regional lung ventilation and microstructure, focusing on morphological and micro-structural (alveolar) abnormalities.

METHODS

Nine patients with left-sided CDH, born 1975-1993, were studied. Regional ventilation was imaged with hyperpolarised (3) He MRI, and the (3) He apparent diffusion coefficient (ADC) was computed separately for the ipsilateral and contralateral lungs. (1) H MRI was used to image lung anatomy, total lung volume and motion during free-breathing.

RESULTS

(3) He MRI showed ventilation abnormalities in six patients, ranging from a single ipsilateral ventilation defect (3 patients) to multiple ventilation defects in both lungs (one patient treated with extra corporeal membrane oxygenation). In eight patients, (3) He ADC values for the ipsilateral lung were significantly higher than those for the contralateral lung.

CONCLUSIONS

Functional and micro-structural changes persist into adulthood in most CDH patients. Ipsilateral elevated (3) He ADC values are consistent with enlargement of mean dimensions of the confining lung micro-structure at the alveolar level.

Challenges in Collating Spirometry Reference Data for South-Asian Children: An Observational Study

Availability of sophisticated statistical modelling for developing robust reference equations has improved interpretation of lung function results. In 2012, the Global Lung function Initiative(GLI) published the first global all-age, multi-ethnic reference equations for spirometry but these lacked equations for those originating from the Indian subcontinent (South-Asians). The aims of this study were to assess the extent to which existing GLI-ethnic adjustments might fit South-Asian paediatric spirometry data, assess any similarities and discrepancies between South-Asian datasets and explore the feasibility of deriving a suitable South-Asian GLI-adjustment.

The development of bronchiectasis on chest computed tomography in children with cystic fibrosis: can pre-stages be identified?

Objective

Bronchiectasis is an important component of cystic fibrosis (CF) lung disease but little is known about its development. We aimed to study the development of bronchiectasis and identify determinants for rapid progression of bronchiectasis on chest CT.

Methods

Forty-three patients with CF with at least four consecutive biennial volumetric CTs were included. Areas with bronchiectasis on the most recent CT were marked as regions of interest (ROIs). These ROIs were generated on all preceding CTs using deformable image registration. Observers indicated whether: bronchiectasis, mucus plugging, airway wall thickening, atelectasis/consolidation or normal airways were present in the ROIs.

Results

We identified 362 ROIs on the most recent CT. In 187 (51.7 %) ROIs bronchiectasis was present on all preceding CTs, while 175 ROIs showed development of bronchiectasis. In 139/175 (79.4 %) no pre-stages of bronchiectasis were identified. In 36/175 (20.6 %) bronchiectatic airways the following pre-stages were identified: mucus plugging (17.7 %), airway wall thickening (1.7 %) or atelectasis/consolidation (1.1 %). Pancreatic insufficiency was more prevalent in the rapid progressors compared to the slow progressors (p = 0.05).

Conclusion

Most bronchiectatic airways developed within 2 years without visible pre-stages, underlining the treacherous nature of CF lung disease. Mucus plugging was the most frequent pre-stage.

Key Points

• Development of bronchiectasis in cystic fibrosis lung disease on CT.

• Most bronchiectatic airways developed within 2 years without pre-stages.

• The most frequently identified pre-stage was mucus plugging.

• This study underlines the treacherous nature of CF lung disease.

Electronic supplementary material

The online version of this article (doi:10.1007/s00330-016-4329-z) contains supplementary material, which is available to authorized users.

Polynomial estimation of the smoothing splines for the new Finnish reference values for spirometry

Background Discontinuity of spirometry reference values from childhood into adulthood has been a problem with traditional reference values, thus modern modelling approaches using smoothing spline functions to better depict the transition during growth and ageing have been recently introduced. Following the publication of the new international Global Lung Initiative (GLI2012) reference values also new national Finnish reference values have been calculated using similar GAMLSS-modelling, with spline estimates for mean (Mspline) and standard deviation (Sspline) provided in tables. The aim of this study was to produce polynomial estimates for these spline functions to use in lieu of lookup tables and to assess their validity in the reference population of healthy non-smokers. Methods Linear regression modelling was used to approximate the estimated values for Mspline and Sspline using similar polynomial functions as in the international GLI2012 reference values. Estimated values were compared to original calculations in absolute values, the derived predicted mean and individually calculated z-scores using both values. Results Polynomial functions were estimated for all 10 spirometry variables. The agreement between original lookup table-produced values and polynomial estimates was very good, with no significant differences found. The variation slightly increased in larger predicted volumes, but a range of -0.018 to +0.022 litres of FEV1 representing ± 0.4% of maximum difference in predicted mean. Conclusions Polynomial approximations were very close to the original lookup tables and are recommended for use in clinical practice to facilitate the use of new reference values.

Thoracic Insufficiency Syndrome

Thoracic insufficiency syndrome (TIS) is a broad grouping of disorders that have a substantial impact on the chest wall, spine, and in many situations, both. While the conditions are varied, they share a potentially substantial impact on respiratory capacity and development over time and a presentation and need for intervention that is often in early childhood. Addressing these conditions has required a new paradigm that involves both deformity correction and a preservation of growth capacity. While there are now a number of options to treat severe spinal deformity early in life, when the deformity causes or is caused by a chest wall deformity, the Vertical Expandable Prosthetic Titanium Rib(VEPTR) is able to support surgical correction of both. The skeletal correction is often quite dramatic, but the functional measurements of quality of life and pulmonary function often do not show as dramatic and improvement, but consistently show a stabilization indicating control of the progressive thoracospinal disorder that produced TIS.

Phenotype of normal spirometry in an aging population

RATIONALE

In aging populations, the commonly used Global Initiative for Chronic Obstructive Lung Disease (GOLD) may misclassify normal spirometry as respiratory impairment (airflow obstruction and restrictive pattern), including the presumption of respiratory disease (chronic obstructive pulmonary disease [COPD]).

OBJECTIVES

To evaluate the phenotype of normal spirometry as defined by a new approach from the Global Lung Initiative (GLI), overall and across GOLD spirometric categories.

METHODS

Using data from COPDGene (n = 10,131; ages 45-81; smoking history, ≥10 pack-years), we evaluated spirometry and multiple phenotypes, including dyspnea severity (Modified Medical Research Council grade 0-4), health-related quality of life (St. George's Respiratory Questionnaire total score), 6-minute-walk distance, bronchodilator reversibility (FEV1 % change), computed tomography-measured percentage of lung with emphysema (% emphysema) and gas trapping (% gas trapping), and small airway dimensions (square root of the wall area for a standardized airway with an internal perimeter of 10 mm).

MEASUREMENTS AND MAIN RESULTS

Among 5,100 participants with GLI-defined normal spirometry, GOLD identified respiratory impairment in 1,146 (22.5%), including a restrictive pattern in 464 (9.1%), mild COPD in 380 (7.5%), moderate COPD in 302 (5.9%), and severe COPD in none. Overall, the phenotype of GLI-defined normal spirometry included normal adjusted mean values for dyspnea grade (0.8), St. George's Respiratory Questionnaire (15.9), 6-minute-walk distance (1,424 ft [434 m]), bronchodilator reversibility (2.7%), % emphysema (0.9%), % gas trapping (10.7%), and square root of the wall area for a standardized airway with an internal perimeter of 10 mm (3.65 mm); corresponding 95% confidence intervals were similarly normal. These phenotypes remained normal for GLI-defined normal spirometry across GOLD spirometric categories.

CONCLUSIONS

GLI-defined normal spirometry, even when classified as respiratory impairment by GOLD, included adjusted mean values in the normal range for multiple phenotypes. These results suggest that among adults with GLI-defined normal spirometry, GOLD may misclassify normal phenotypes as having respiratory impairment.

Lung VITAL: Rationale, design, and baseline characteristics of an ancillary study evaluating the effects of vitamin D and/or marine omega-3 fatty acid supplements on acute exacerbations of chronic respiratory disease, asthma control, pneumonia and lung function in adults

Laboratory and observational research studies suggest that vitamin D and marine omega-3 fatty acids may reduce risk for pneumonia, acute exacerbations of respiratory diseases including chronic obstructive lung disease (COPD) or asthma, and decline of lung function, but prevention trials with adequate dosing, adequate power, and adequate time to follow-up are lacking. The ongoing Lung VITAL study is taking advantage of a large clinical trial-the VITamin D and OmegA-3 TriaL (VITAL)--to conduct the first major evaluation of the influences of vitamin D and marine omega-3 fatty acid supplementation on pneumonia risk, respiratory exacerbation episodes, asthma control and lung function in adults. VITAL is a 5-year U.S.-wide randomized, double-blind, placebo-controlled, 2 × 2 factorial trial of supplementation with vitamin D3 ([cholecalciferol], 2000 IU/day) and marine omega-3 FA (Omacor® fish oil, eicosapentaenoic acid [EPA]+docosahexaenoic acid [DHA], 1g/day) for primary prevention of CVD and cancer among men and women, at baseline aged ≥50 and ≥55, respectively, with 5107 African Americans. In a subset of 1973 participants from 11 urban U.S. centers, lung function is measured before and two years after randomization. Yearly follow-up questionnaires assess incident pneumonia in the entire randomized population, and exacerbations of respiratory disease, asthma control and dyspnea in a subpopulation of 4314 randomized participants enriched, as shown in presentation of baseline characteristics, for respiratory disease, respiratory symptoms, and history of cigarette smoking. Self-reported pneumonia hospitalization will be confirmed by medical record review, and exacerbations will be confirmed by Center for Medicare and Medicaid Services data review.

Validating chest MRI to detect and monitor cystic fibrosis lung disease in a pediatric cohort

BACKGROUND

Computed Tomography (CT) is the gold standard to assess bronchiectasis and trapped air in cystic fibrosis (CF) lung disease, but has the disadvantage of radiation exposure. Magnetic Resonance Imaging (MRI) is a radiation free alternative.

OBJECTIVE

To validate MRI as outcome measure by: correlating MRI scores for bronchiectasis and trapped air with clinical parameters, and by comparing those MRI scores with CT scores.

METHODS

In patients with CF (aged 5.6-17.4 years), MRI and CT were alternated annually during routine annual check-ups between July 2007 and January 2010. Twenty-three children had an MRI performed 1 year prior to CT, 34 children had a CT 1 year prior to MRI. Bronchiectasis and trapped air were scored using the CF-MRI and CF-CT scoring system. CF-MRI scores were correlated with clinical parameters: FEV1 , Pseudomonas aeruginosa, pulmonary exacerbations and patient-reported respiratory symptoms measured on the Cystic Fibrosis Questionnaire-Revised (CFQ-R), using Spearman's correlation coefficient. MRI and CT scores were compared using intra-class correlation coefficients (ICC) and Bland-Altman plots.

RESULTS

Fifty-seven patients who had an MRI, CT and CFQ-R during the study period were included. CF-MRI bronchiectasis correlated with FEV1 , Pseudomonas aeruginosa, pulmonary exacerbations and patient-reported respiratory symptoms. CF-MRI trapped air only correlated with FEV1 and Pseudomonas aeruginosa. ICCs between MRI and CT bronchiectasis and trapped air were 0.41 and 0.35 respectively. MRI tended to overestimate bronchiectasis compared to CT.

CONCLUSION

The associations between CF-MRI scores and several important clinical parameters further contributes to the validation of MRI. MRI provides different information than CT.

Respiratory Function and Language Abilities of Profoundly Deaf Adolescents with and without Cochlear Implants

The objective of the study was to investigate whether hearing loss has an effect on the ventilatory functional capability and whether possible deviations of ventilatory variables from the reference ranges could have to do with the language abilities of deaf adolescents. Spirometric evaluations were performed in 72 prelingually profoundly deaf adolescents with and without cochlear implants (CI) and compared with the results of a control group consisting of 48 participants with normal hearing (CG). The deaf adolescents showed a significantly lower vital capacity (VC), forced vital capacity (FVC), and expiratory flows (PEF and MEF) compared with their hearing peers. The adolescents with CI demonstrated predominantly the oral communication mode, which however did not affect the students' education achievements. Perseverance of oral communication was also associated with higher FVC and PEF, compared with deaf participants without CI. We conclude that sensory deprivation of prelingually deaf adolescents affects the respiratory system function. The use of oral communication seems to have beneficial effects on respiratory performance in profoundly deaf adolescents.

Clinical heterogeneity of dominant chronic mucocutaneous candidiasis disease: presenting as treatment-resistant candidiasis and chronic lung disease

In gain-of-function STAT1 mutations, chronic mucocutaneous candidiasis disease (CMCD) represents the phenotypic manifestation of a complex immunodeficiency characterized by clinical and immunological heterogeneity. We aimed to study clinical manifestations, long-term complications, molecular basis, and immune profile of patients with dominant CMCD. We identified nine patients with heterozygous mutations in STAT1, including novel amino acid substitutions (L283M, L351F, L400V). High risk of azole-resistance was observed, particularly when intermittent regimens of antifungal treatment or use of suboptimal dosage occurs. We report a case of Cryptococcosis and various bacterial and viral infections. Risk of developing bronchiectasis in early childhood or gradually evolving to chronic lung disease in adolescent or adult ages emerges. Lymphopenia is variable, likely progressing by adulthood. We conclude that continuous antifungal prophylaxis associated to drug monitoring might prevent resistance to treatment; prompt diagnosis and therapy of lung disease might control long-term progression; careful monitoring of lymphopenia-related infections might improve prognosis.

Epidemiology of Chronic Obstructive Pulmonary Disease (COPD) in Aging Populations

Current epidemiologic practice evaluates COPD based on self-reported symptoms of chronic bronchitis, self-reported physician-diagnosed COPD, spirometry confirmed airflow obstruction, or emphysema diagnosed by volumetric computed chest tomography (CT). Because the highest risk population for having COPD includes a predominance of middle-aged or older persons, aging related changes must also be considered, including: 1) increased multimorbidity, polypharmacy, and severe deconditioning, as these identify mechanisms that underlie respiratory symptoms and can impart a complex differential diagnosis; 2) increased airflow limitation, as this impacts the interpretation of spirometry confirmed airflow obstruction; and 3) "senile" emphysema, as this impacts the specificity of CT-diagnosed emphysema. Accordingly, in an era of rapidly aging populations worldwide, the use of epidemiologic criteria that do not rigorously consider aging related changes will result in increased misidentification of COPD and may, in turn, misinform public health policy and patient care.

Aging-Related Considerations When Evaluating the Forced Expiratory Volume in 1 Second (FEV1) Over Time

BACKGROUND

Forced expiratory volume in 1 second (FEV1) over time is commonly expressed in liters and percent predicted (%Pred), or alternatively in L/m(3) and Z-scores-which approach is more clinically meaningful has not been evaluated. Because it uniquely accounts for the effect of aging on FEV1 and spirometric performance, we hypothesized that the Z-score approach is more clinically meaningful, based on associations between cardiopulmonary predictors and FEV1 over time.

METHODS

Using linear mixed-effects models and data from the Baltimore Longitudinal Study on Aging, including 501 white participants aged 40-95 who had completed at least three longitudinal spirometric assessments, we evaluated the associations between cardiopulmonary predictors (obesity, smoking status, hypertension, chronic bronchitis, diabetes mellitus, and myocardial infarction) and FEV1 over time, in liters, %Pred, L/m(3), and Z-scores.

RESULTS

Mean baseline values for FEV1 were 3.240L, 96.4%Pred, 0.621L/m(3), and -0.239 as a Z-score (40.6th percentile). The annual decline in FEV1 was 0.040L, 0.234 %Pred, 0.007L/m(3), and 0.008 Z-score units. Baseline age was associated with FEV1 over time in liters and L/m(3) (p < .001), and included a time interaction for %Pred (p < .001), but was not associated with Z-scores (p = .933). The associations of cardiopulmonary predictors with FEV1 over time were all significant when using Z-scores (p < .05), but varied for other methods of expressing FEV1.

CONCLUSION

A Z-score approach is more clinically meaningful when evaluating FEV1 over time, as it accounted for the effect of aging and was more frequently associated with multiple cardiopulmonary predictors.

Bleomycin-associated Lung Toxicity in Childhood Cancer Survivors

Pulmonary disease is a significant morbidity among childhood cancer survivors. The aim of this study was to characterize the pulmonary dysfunction experienced by childhood cancer survivors treated with bleomycin. A cross-sectional analysis of pulmonary function testing (PFT) in survivors treated with bleomycin was preformed. The most recent posttherapy PFT was assessed. Spirometry and lung volumes were categorized as normal, restrictive, obstructive, or mixed. Diffusing capacity of carbon monoxide (DLCO) was categorized as normal or abnormal. PFT data of 143 survivors was analyzed. PFTs were performed a median of 2.3 years (interquartile range, 1.4 to 4.9) from completion of therapy. Spirometry was abnormal in 58 (41%), only 5 (9%) had respiratory symptoms. Forty-two (70%) had obstructive, 11 (18%) restrictive, and 5 (9%) mixed ventilatory defects. The majority of abnormalities were mild (91%). DLCO was abnormal in 27. Reductions were mild in 96%. Patients with a history of relapse were more likely to develop abnormalities in spirometry and/or DLCO (odds ratio=5.02, 95% confidence interval: 1.3-19.4, P=0.01; odds ratio=3.47, 95% confidence interval: 1.01-11.9, P=0.03). Asymptomatic abnormalities of PFT are common among childhood cancer survivors treated with bleomycin and associated with a history of relapse. Research studying the risk for clinical progression of this dysfunction is warranted.

Adolescents who were born extremely preterm demonstrate modest decreases in exercise capacity

AIM

We aimed to investigate exercise capacity in adolescents who were born extremely preterm and to study changes through puberty and associations with neonatal data, exercise habits and lung function.

METHODS

This Norwegian population-based controlled cohort study focused on all infants (n = 35) born at a gestational age of ≤ 28 weeks or with a birthweight of ≤ 1000 grams in 1991-1992, together with matched term-born controls. Participants underwent spirometry and a maximal cardiopulmonary treadmill exercise test at 10 and 18 years.

RESULTS

At 18 years of age, mean (95% confidence interval) peak oxygen consumption (peak VO2 ) was 42.3 (39.2-45.4) vs 45.3 (41.3-49.3) mL/kg/min in the preterm- and term-born groups, while the completed treadmill distance was 915 (837-992) vs 1017 (912-1122) metres. Peak VO2 was unrelated to neonatal factors and current lung function. Changes between 10 and 18 were similar in the two groups, and positive associations between exercise habits and peak VO2 developed during the period.

CONCLUSION

Exercise capacity was modestly reduced in adolescents born extremely preterm, but the values were considered normal in most participants. Changes during puberty were similar to those observed for term controls, and the findings suggest similar trainability.

Physiologic findings in children previously ventilator dependent at home due to bronchopulmonary dysplasia

INTRODUCTION

Bronchopulmonary dysplasia (BPD) is the primary respiratory complication of premature birth. Some preterm newborns develop chronic respiratory failure, requiring home ventilator support. While physiologic measures have been described for prematurely born children, little is known about spirometric indices in patients with severe BPD who were previously ventilator dependent at home.

METHODS

We retrospectively reviewed medical charts of patients with severe BPD who were ventilator dependent at home. We excluded patients with other comorbidities that could contribute to the severity of BPD. Spirometry was performed when the patient was able to follow commands.

RESULTS

Between 1984 and 2012, within our severe BPD cohort who previously required home ventilator support, 19 patients were able to perform reproducible spirometry meeting ATS/ERS acceptability criteria. Ten (52.6%) were females, 13 (68.4%) were Caucasians. Mean age at liberation from ventilation was 2.4 years (C.I. 2.0, 2.9) and at decannulation was 3.5 years (C.I. 2.9, 4.0); median age at first reproducible spirometry measurement was 6.6 years (IQR: 4.9, 8.3). Spirometry results revealed significant airway obstruction, as demonstrated by Z-scores values of -1.5 (C.I. -2.5, -0.4) for FVC, -2.7 (C.I. -3.3, -1.9) for FEV1 , and -3.6 (C.I. -4.3, -2.9) for FEF25-75 . More so, serial spirometric measurements' slopes revealed that the airway obstruction remained static over time (FEV1 slope: -0.07, P-value: 0.2624; FVC slope: -0.01, P-value: 0.9064; and FEF25-75 : 0.0, P-value: 0.8532).

CONCLUSIONS

Extreme prematurity associated with severe BPD requiring home ventilator support carries significant risks of morbidity. These patients had substantially diminished respiratory function reflecting airflow abnormalities that remained static over time.

The Effects of Bikram Yoga on Health: Critical Review and Clinical Trial Recommendations

Bikram yoga is a style of hatha yoga involving a standarized series of asanas performed to an instructional dialogue in a heated environment (40.6°C, 40% humidity). Several studies evaluating the effect of Bikram yoga on health-related outcomes have been published over the past decade. However, to date, there are no comprehensive reviews of this research and there remains a lack of large-scale, robustly-designed randomised controlled trials (RCT) of Bikram yoga training. The purpose of this review is to contextualise and summarise trials that have evaluated the effects of Bikram yoga on health and to provide recommendations for future research. According to published literature, Bikram yoga has been shown to improve lower body strength, lower and upper body range of motion, and balance in healthy adults. Non-RCTs report that Bikram yoga may, in some populations, improve glucose tolerance, bone mineral density, blood lipid profile, arterial stiffness, mindfulness, and perceived stress. There is vast potential for further, improved research into the effects of Bikram yoga, particularly in unhealthy populations, to better understand intervention-related adaptations and their influence on the progression of chronic disease. Future research should adhere to CONSORT guidelines for better design and reporting to improve research quality in this field.

Dynamic Latent Trait Models with Mixed Hidden Markov Structure for Mixed Longitudinal Outcomes

We propose a general Bayesian joint modeling approach to model mixed longitudinal outcomes from the exponential family for taking into account any differential misclassification that may exist among categorical outcomes. Under this framework, outcomes observed without measurement error are related to latent trait variables through generalized linear mixed effect models. The misclassified outcomes are related to the latent class variables, which represent unobserved real states, using mixed hidden Markov models (MHMM). In addition to enabling the estimation of parameters in prevalence, transition and misclassification probabilities, MHMMs capture cluster level heterogeneity. A transition modeling structure allows the latent trait and latent class variables to depend on observed predictors at the same time period and also on latent trait and latent class variables at previous time periods for each individual. Simulation studies are conducted to make comparisons with traditional models in order to illustrate the gains from the proposed approach. The new approach is applied to data from the Southern California Children Health Study (CHS) to jointly model questionnaire based asthma state and multiple lung function measurements in order to gain better insight about the underlying biological mechanism that governs the inter-relationship between asthma state and lung function development.

Spirometric reference values for healthy Han children aged 5-15 years in Guangzhou, southern China

BACKGROUND

Reliable interpretation of spirometry rests on appropriate reference values, but there are few published reference values for healthy children in China.

OBJECTIVE

To develop the updated spirometric normative values for healthy children aged 5-15 years in Guangzhou, southern China, and to explore the differences by comparison with published reference values.

METHODS

In this cross-sectional study, health questionnaire and physical examination conducted for screening healthy Han children. Spirometry was performed by well-trained technicians according to American Thoracic Society guidelines. Using Lambda-Mu-Sigma (LMS) algorithm, predicted equations for the median and lower limits of normal were derived for forced vital capacity (FVC), forced expiratory volume in one second (FEV1 ), peak expiratory flow (PEF), and maximal mid-expiratory flow (FEF25-75% ). Predicted values were compared with other published spirometric reference equations.

RESULTS

Data were obtained from 422 healthy children (226 boys and 196 girls) aged 5-15 years. Spirometric parameters showed moderate-to-strong positive correlations with age, height, and weight in both genders, with height being the most crucial predictor. There were significant differences between spirometric values and other published reference values. Spirometric values were comparable with the data derived from the same area population in 2002, with exception of increased height and weight in the equivalent age groups.

CONCLUSIONS

The present spirometric reference equations are feasible for assessment of lung function among children in southern China. Further studies for establishment of reference values for Chinese children in other regions are needed.

Associations of lifelong cigarette consumption and hypertension with airflow limitation in primary care clinic outpatients in Japan

BACKGROUND

Underdiagnosis is a critical problem in the management of chronic obstructive pulmonary disease (COPD). It is important to screen patients at risk for COPD among those with lifestyle-related diseases such as hypertension, diabetes mellitus, and dyslipidemia, since these diseases promote the development of cardiovascular diseases closely associated with increased COPD mortality.

METHODS

Thirteen primary care clinics in a suburb of Tokyo participated in the current study. A total of 950 patients from these clinics were enrolled in the study between 2010 and 2012; the patients ranged in age from 40 to 79 years, and they had no diagnosed respiratory diseases at the time of enrollment. Patients fulfilling the selection criteria were recruited to undergo spirometry and then completed a self-report questionnaire about comorbid diseases and smoking habits. Spirometry was performed 15 min after inhalation of 200 μg of salbutamol sulfate.

RESULTS

The prevalence of airflow limitation was 12.7% in the 950 primary care clinic patients. Lifelong cigarette consumption was the most significant risk factor for airflow limitation, e.g., patients who smoked 60 pack-years or more had a 40% likelihood of airflow limitation. Among common lifestyle-related diseases, hypertension was associated with the severity of airflow limitation (p=0.03), whereas dyslipidemia appeared to be inversely correlated with the severity of airflow limitation (p=0.004) on multiple regression analysis including lifelong cigarette consumption as a factor.

CONCLUSIONS

Undiagnosed airflow limitation was detected in 12.7% of outpatients at the primary care clinics. Since most patients with lifestyle-related diseases are treated by primary care physicians, it is essential for the physicians to obtain an accurate history of smoking and comorbid diseases to screen patients for COPD.

Two distinct phenotypes of asthma in elite athletes identified by latent class analysis

INTRODUCTION

Clusters of asthma in athletes have been insufficiently studied. Therefore, the present study aimed to characterize asthma phenotypes in elite athletes using latent class analysis (LCA) and to evaluate its association with the type of sport practiced.

METHODS

In the present cross-sectional study, an analysis of athletes' records was carried out in databases of the Portuguese National Anti-Doping Committee and the Norwegian School of Sport Sciences. Athletes with asthma, diagnosed according to criteria given by the International Olympic Committee, were included for LCA. Sports practiced were categorized into water, winter and other sports.

RESULTS

Of 324 files screened, 150 files belonged to asthmatic athletes (91 Portuguese; 59 Norwegian). LCA retrieved two clusters: "atopic asthma" defined by allergic sensitization, rhinitis and allergic co-morbidities and increased exhaled nitric oxide levels; and "sports asthma", defined by exercise-induced respiratory symptoms and airway hyperesponsiveness without allergic features. The risk of developing the phenotype "sports asthma" was significantly increased in athletes practicing water (OR = 2.87; 95% CI [1.82-4.51]) and winter (OR = 8.65; 95% CI [2.67-28.03]) sports, when compared with other athletes.

CONCLUSION

Two asthma phenotypes were identified in elite athletes: "atopic asthma" and "sports asthma". The type of sport practiced was associated with different phenotypes: water and winter sport athletes had three- and ninefold increased risk of "sports asthma". Recognizing different phenotypes is clinically relevant as it would lead to distinct targeted treatments.

Salivary Telomere Length and Lung Function in Adolescents Born Very Preterm: A Prospective Multicenter Study

Preterm birth is associated with abnormal respiratory functions throughout life. The mechanisms underlying these long-term consequences are still unclear. Shortening of telomeres was associated with many conditions, such as chronic obstructive pulmonary disease. We aimed to search for an association between telomere length and lung function in adolescents born preterm. Lung function and telomere length were measured in 236 adolescents born preterm and 38 born full-term from the longitudinal EPIPAGE cohort. Associations between telomere length and spirometric indices were tested in univariate and multivariate models accounting for confounding factors in the study population. Airflows were significantly lower in adolescents born preterm than controls; forced expiratory volume in one second was 12% lower in the extremely preterm born group than controls (p<0.001). Lower birth weight, bronchopulmonary dysplasia and postnatal sepsis were significantly associated with lower airflow values. Gender was the only factor that was significantly associated with telomere length. Telomere length correlated with forced expiratory flow 25–75 in the extremely preterm adolescent group in univariate and multivariate analyses (p = 0.01 and p = 0.02, respectively). We evidenced an association between telomere length and abnormal airflow in a population of adolescents born extremely preterm. There was no evident association with perinatal events. This suggests other involved factors, such as a continuing airway oxidative stress leading to persistent inflammation and altered lung function, ultimately increasing susceptibility to chronic obstructive pulmonary disease.

Different KCO and VA combinations exist for the same DLCO value in patients with diffuse parenchymal lung diseases

Background

DL_CO is the product of the CO transfer coefficient (K_CO) by the “accessible” alveolar volume (V_A). In theory, the same DL_CO may result from various combinations of K_CO and V_A values, each of which reflect different injury sites and mechanisms. We sought to determine in this study the potential variability of both V_A and K_CO for fixed values of DL_CO in diffuse parenchymal lung diseases (DPLD).

Methods

To this end, we designed a retrospective, cross-sectional study of three distinct types of DPLD and analysed pulmonary function test (PFT) datasets.

Results

We show here that for the same value of DL_CO (50 % predicted), K_CO varied from 60 to 95 % predicted and V_A from 55 to 85 % predicted in various types of DPLD idiopathic pulmonary fibrosis, sarcoidosis and connective tissue disease-associated DPLD, indicating distinct pathogenic mechanisms in these diseases. In addition, a comparison of V_A with total lung capacity may help to evidence the distal airway obstruction sometimes associated with certain DPLD particularly sarcoidosis.

Conclusion

Clinicians should take into account not only DL_CO but also V_A and K_CO values when managing patients with DPLD.

The RESPECT study: RESearch on the PrEvalence and the diagnosis of COPD and its Tobacco-related etiology: a study protocol

BACKGROUND

Smoking remains a leading health risk factor among Europeans. Tobacco, together with other factors, will lead to an expansive epidemic of chronic diseases, including COPD, among the working population in Russia. The general aim of the RESearch on the PrEvalence and the diagnosis of COPD and its Tobacco-related etiology (RESPECT) study is to gain a better understanding of the prevalence, pathogenesis and symptoms of COPD.

METHODS/DESIGN

The RESPECT study is a prospective, population-based cohort study of subjects aged 35-70 years in two north-west regions of the Russian Federation (Saint Petersburg and Arkhangelsk). The study includes three components: a cross-sectional study (prevalence), a case-control study and a cohort study (diagnostic). An investigator who interviewed the patient completed three questionnaires. Spirometry, including a reversibility test, was offered to all participants. Individuals displaying forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) < 0.7 and/or FEV1/FVC < the lower limit of normal before and/or after bronchodilation were included in a follow-up study and were examined by a pulmonologist using a standardized comprehensive examination protocol. A future case-control study of two matched groups of patients (heavy smokers with COPD versus heavy smokers without COPD) will provide information on which factors (biomarkers, including pneumoproteins, in serum and induced sputum) are related to tobacco-induced COPD.

DISCUSSION

In total, 3133 individuals (2122 from St. Petersburg and 1012 from Arkhangelsk) aged 35-70 years agreed to participate in this study and met the inclusion criteria. In total, 2974 participants met the quality criteria for spirometry, and 2388 reversibility tests were performed. A cohort of newly defined obstructive pulmonary disease patients (247 persons) was established for follow-up investigation. The RESPECT study will provide information regarding the prevalence of COPD in the north-west region of the Russian Federation. Moreover, the comprehensive RESPECT database will enable us to explore new research questions, provide novel insight into the risk factors and different phenotypes of COPD, and contribute to an improved understanding of the reasons why some heavy smokers develop the disease whereas others do not.

CLINICAL TRIAL REGISTRATION

NCT02307799 (the release date: 12/01/2014).

Serum club cell protein 16 is associated with asymptomatic airway responsiveness in adults: Findings from the French epidemiological study on the genetics and environment of asthma

BACKGROUND AND OBJECTIVE

Club cell secretory protein (CC-16) is a sensitive biomarker of airways epithelium integrity. It has gained interest as a biological marker in chronic lung diseases because of its presumed relationship to inflammation. Little is known about the association between CC-16 serum level and asthma, lung function and airway responsiveness (AR).

METHODS

Serum CC-16 level was determined by latex immunoassay in 1298 participants from the French Epidemiological case-control and family-based study on Genetics and Environment of Asthma (EGEA) (mean age 43 years; 49% men, 38% with asthma). Pre-bronchodilator lung function (forced expiratory volume in 1 s (FEV1 ), forced vital capacity (FVC) and FEV1 /FVC) and degree of AR, expressed as a function of the dose-response slope to methacholine test were measured. Standardized residuals CC-16 z-scores were obtained by regressing CC-16 level on the glomerular filtration rate. CC-16 z-scores were correlated with asthma, lung function and AR in participants with and without asthma.

RESULTS

CC-16 geometric mean level was 12.4 μg/L (range: 2.2-70.6 μg/L). In participants without asthma, lower CC-16 z-scores was associated with impaired FEV1 /FVC% (β = 0.50 (95% CI: 0.06, 0.95) and with higher degree of AR (β = 0.24 (95% CI: 0.09, 0.39)). CC-16 was not associated with impaired lung function or AR in participants with asthma.

CONCLUSIONS

Lower CC-16 serum level was associated with impaired lung function and AR, suggesting that serum CC-16 level may reflect early damages to the lung epithelium in adults without asthma.

Air Pollution by Hydrothermal Volcanism and Human Pulmonary Function

The aim of this study was to assess whether chronic exposure to volcanogenic air pollution by hydrothermal soil diffuse degassing is associated with respiratory defects in humans. This study was carried in the archipelago of the Azores, an area with active volcanism located in the Atlantic Ocean where Eurasian, African, and American lithospheric plates meet. A cross-sectional study was performed on a study group of 146 individuals inhabiting an area where volcanic activity is marked by active fumarolic fields and soil degassing (hydrothermal area) and a reference group of 359 individuals inhabiting an area without these secondary manifestations of volcanism (nonhydrothermal area). Odds ratio (OR) and 95% confidence intervals (CIs) were adjusted for age, gender, fatigue, asthma, and smoking. The OR for restrictive defects and for exacerbation of obstructive defects (COPD) in the hydrothermal area was 4.4 (95% CI 1.78-10.69) and 3.2 (95% CI 1.82-5.58), respectively. Increased prevalence of restrictions and all COPD severity ranks (mild, moderate, and severe) was observed in the population from the hydrothermal area. These findings may assist health officials in advising and keeping up with these populations to prevent and minimize the risk of respiratory diseases.

Lower Extremity Proximal Muscle Function and Dyspnea in Older Persons

OBJECTIVES

To evaluate the association between performance on a single chair stand and moderate to severe exertional dyspnea.

DESIGN

Cross-sectional.

SETTING

Cardiovascular Health Study.

PARTICIPANTS

Community-dwelling individuals aged 65 and older (N = 4,413; mean age 72.6; female, n = 2,518 (57.1%); nonwhite, n = 199 (4.5%); obese, n = 788 (17.9%); history of smoking, n = 2,410 (54.6%)).

MEASUREMENTS

Performance on single chair stand (poor (unable to rise without arm use) vs normal (able to rise without arm use)), moderate to severe exertional dyspnea (American Thoracic Society grade ≥2), age, sex, ethnicity, obesity, smoking, frailty status (Fried-defined nonfrail, prefrail, frail), high cardiopulmonary risk (composite of cardiopulmonary diseases and diabetes mellitus), spirometric impairment, arthritis, depression, stroke, and kidney disease.

RESULTS

Poor performance on the single chair stand was established in 369 (8.4%) and moderate to severe exertional dyspnea in 773 (17.5%). Prefrail status was established in 2,210 (50.1%), frail status in 360 (8.2%), arthritis in 2,241 (51.4%), high cardiopulmonary risk in 2,469 (55.9%), spirometric impairment in 1,076 (24.4%), kidney disease in 111 (2.5%), depression in 107 (2.4%), and stroke in 93 (2.1%). In multivariable regression models, poor performance on the single chair stand was associated with moderate to severe exertional dyspnea (unadjusted odds ratio (OR) = 3.48, 95% confidence interval (CI) = 2.78-4.36; adjusted OR = 1.85, 95% CI = 1.41-2.41).

CONCLUSION

Poor performance on a single chair stand was associated with an adjusted 85% greater likelihood of moderate to severe exertional dyspnea than normal performance. These results suggest that reduced proximal muscle function of the lower extremities is associated with moderate to severe exertional dyspnea, even after adjusting for multiple confounders.

Reference values for spirometry - report from the Obstructive Lung Disease in Northern Sweden studies

BACKGROUND

Abnormal lung function is commonly identified by comparing observed spirometric values to corresponding reference values. It is recommended that such reference values for spirometry are evaluated and updated frequently. The aim of this study was to estimate new reference values for Swedish adults by fitting a multivariable regression model to a healthy non-smoking general population sample from northern Sweden. Further aims were to evaluate the external validity of the obtained reference values on a contemporary sample from south-western Sweden, and to compare them to the Global Lung Function Initiative (GLI) reference values.

METHOD

Sex-specific multivariable linear regression models were fitted to the spirometric data of n=501 healthy non-smoking adults aged 22-91 years, with age and height as predictors. The models were extended to allow the scatter around the outcome variable to depend on age, and age-dependent spline functions were incorporated into the models to provide a smooth fit over the entire age range. Mean values and lower limits of normal, defined as the lower 5th percentiles, were derived.

RESULT

This modelling approach resulted in unbiased estimates of the spirometric outcomes, and the obtained estimates were appropriate not only for the northern Sweden sample but also for the south-western Sweden sample. On average, the GLI reference values for forced expiratory volume in one second (FEV1) and, in particular, forced expiratory vital capacity (FVC) were lower than both the observed values and the new reference values, but higher for the FEV1/FVC ratio.

CONCLUSION

The evaluation based on the sample of healthy non-smokers from northern Sweden show that the Obstructive Lung Disease in Northern Sweden reference values are valid. Furthermore, the evaluation based on the south-western Sweden sample indicates a high external validity. The comparison with GLI brought further evidence to the consensus that, when available, appropriate local population-specific reference values may be preferred.

Distinguishing Asthma Phenotypes Using Machine Learning Approaches

Asthma is not a single disease, but an umbrella term for a number of distinct diseases, each of which are caused by a distinct underlying pathophysiological mechanism. These discrete disease entities are often labelled as 'asthma endotypes'. The discovery of different asthma subtypes has moved from subjective approaches in which putative phenotypes are assigned by experts to data-driven ones which incorporate machine learning. This review focuses on the methodological developments of one such machine learning technique-latent class analysis-and how it has contributed to distinguishing asthma and wheezing subtypes in childhood. It also gives a clinical perspective, presenting the findings of studies from the past 5 years that used this approach. The identification of true asthma endotypes may be a crucial step towards understanding their distinct pathophysiological mechanisms, which could ultimately lead to more precise prevention strategies, identification of novel therapeutic targets and the development of effective personalized therapies.

Implementation of a targeted screening program to detect airflow obstruction suggestive of chronic obstructive pulmonary disease within a presurgical screening clinic

BACKGROUND

Targeted spirometry screening for chronic obstructive pulmonary disease (COPD) has been studied in primary care and community settings. Limitations regarding availability and quality of testing remain. A targeted spirometry screening program was implemented within a presurgical screening (PSS) clinic to detect undiagnosed airways disease and identify patients with COPD/asthma in need of treatment optimization.

OBJECTIVE

The present quality assurance study evaluated airflow obstruction detection rates and examined characteristics of patients identified through the targeted screening program.

METHODS

The targeted spirometry screening program was implemented within the PSS clinic of a tertiary care university hospital. Current or ex-smokers with respiratory symptoms and patients with a history of COPD or asthma underwent prebronchodilator spirometry. History of airways disease and smoking status were obtained during the PSS assessment and confirmed through chart reviews.

RESULTS

After exclusions, the study sample included 449 current or ex-smokers. Abnormal spirometry results were found in 184 (41%) patients: 73 (16%) had mild, 93 (21%) had moderate and 18 (4%) had severe or very severe airflow obstruction. One hundred eighteen (26%) new cases of airflow obstruction suggestive of COPD were detected. One-half of these new cases had moderate or severe airflow obstruction. Only 34% of patients with abnormal spirometry results had reported a previous diagnosis of COPD. More than one-half of patients with abnormal spirometry results were current smokers.

CONCLUSIONS

Undiagnosed airflow obstruction was detected in a significant number of smokers and ex-smokers through a targeted screening program within a PSS clinic. These patients can be referred for early intervention and secondary preventive strategies.

Small airways dysfunction in long-term survivors of pediatric stem cell transplantation

BACKGROUND

Chronic graft-versus-host disease (cGvHD) in the lungs is a life-threatening complication of allogeneic hematopoietic stem cell transplantation (HSCT). Pulmonary cGvHD is initiated in the peripheral airways, and diagnosis may be delayed by low sensitivity of standard pulmonary function tests. Multiple breath nitrogen washout (MBWN2 ) is a promising, sensitive method to assess small airways function. This is the first report on MBWN2 in survivors of pediatric HSCT.

METHODS

This cross-sectional study undertaken 3-10 years post-HSCT, included 64 patients and 64 matched controls who all performed spirometry, whole-body plethysmography and MBWN2 . From MBWN2 the lung clearance index (LCI) and indices reflecting ventilation inhomogeneity arising close to the acinar lung zone (Sacin ) and in the conductive airway zone (Scond ) were derived. Subjective respiratory morbidity was assessed using the St. George Respiratory Questionnaire.

RESULTS

LCI, Sacin , and Scond were significantly higher in HSCT-patients compared with controls. Despite few reported symptoms and normal forced expiratory volume in 1 sec (FEV1 ) in 91%, LCI, Scond , and Sacin were abnormal in 34%, 52%, and 25% of HSCT-patients, respectively. LCI and Scond correlated weakly with spirometric findings in HSCT-patients, but not in controls. Scond was abnormal in 82% (9/11) of patients with evidence of cGvHD, and was associated with cGvHD in the multivariate analysis (r(2)  = 0.26, P = 0.001).

CONCLUSIONS

Small airways dysfunction as measured by MBWN2 was a common finding at long term follow-up of children after allogeneic HSCT and was associated with cGvHD. The majority of these subjects had normal spirometric values and did not report any respiratory symptoms. Prospective studies are required to evaluate the long term clinical consequences of these signs of small airway disease and the value of MBWN2 as an early marker of pulmonary cGvHD.

Impact of childhood anthropometry trends on adult lung function

BACKGROUND

Poor fetal growth rate is associated with lower respiratory function; however, there is limited understanding of the impact of growth trends and BMI during childhood on adult respiratory function.

METHODS

The current study data are from the Mater-University of Queensland Study of Pregnancy birth cohort. Prospective data were available from 1,740 young adults who performed standard spirometry at 21 years of age and whose birth weight and weight, height, and BMI at 5, 14, and 21 years of age were available. Catch-up growth was defined as an increase of 0.67 Z score in weight between measurements. The impact of catch-up growth on adult lung function and the relationship between childhood BMI trends and adult lung function were assessed using regression analyses.

RESULTS

Lung function was higher at 21 years in those demonstrating catch-up growth from birth to 5 years (FVC, men: 5.33 L vs 5.54 L; women: 3.78 L vs 4.03 L; and FEV1, men: 4.52 L/s vs 4.64 L/s; women: 3.31 L/s vs 3.45 L/s). Subjects in the lowest quintile of birth (intrauterine growth retardation) also showed improved lung function if they had catch-up growth in the first 5 years of life. There was a positive correlation between increasing BMI and lung function at 5 years of age. However, in the later measurements when BMI increased into the obese category, a drop in lung function was observed.

CONCLUSIONS

These data show evidence for a positive contribution of catch-up growth in early life to adult lung function. However, if weight gain or onset of obesity occurs after 5 years of age, an adverse impact on adult lung function is noted.