Small airway loss in the physiologically ageing lung: a cross-sectional study in unused donor lungs.

BACKGROUND: Physiological lung ageing is associated with a gradual decline in dynamic lung volumes and a progressive increase in residual volume due to diminished elastic recoil of the lung, loss of alveolar tissue, and lower chest wall compliance. However, the effects of ageing on the small airways (ie, airways <2·0 mm in diameter) remain largely unknown. By using a combination of ex-vivo conventional CT (resolution 1 mm), whole lung micro-CT (resolution 150 µm), and micro-CT of extracted cores (resolution 10 µm), we aimed to provide a multiresolution assessment of the small airways in lung ageing in a large cohort of never smokers. METHODS: For this cross-sectional study, we included donor lungs collected from 32 deceased never-smoking donors (age range 16-83 years). Ex-vivo CT and whole lung high-resolution CT (micro-CT) were used to determine total airway numbers, stratified by airway diameter. Micro-CT was used to assess the number, length, and diameter of terminal bronchioles (ie, the last generation of conducting airways); mean linear intercept; and surface density in four lung tissue cores from each lung, extracted using a uniform sampling approach. Regression ß coefficients are calculated using linear regression and polynomial models. FINDINGS: Ex-vivo CT analysis showed an age-dependent decrease in the number of airways of diameter 2·0 mm to less than 2·5 mm (ß coefficient per decade -0·119, 95% CI -0·193 to -0·045; R2=0·29) and especially in airways smaller than 2·0 mm in diameter (-0·158, -0·233 to -0·084; R2=0·47), between 30 and 80 years of age, but not of the larger (≥2·5 mm) diameter airways (-0·00781, -0·04409 to 0·02848; R2=0·0007). In micro-CT analysis of small airways, the total number of terminal bronchioles per lung increased until the age of 30 years, after which an almost linear decline in the number of terminal bronchioles was observed (ß coefficient per decade -2035, 95% CI -2818 to -1252; R2=0·55), accompanied by a non-significant increase in alveolar airspace size (6·44, -0·57 to 13·45, R2=0·10). Moreover, this decrease in terminal bronchioles was associated with the age-related decline of pulmonary function predicted by healthy reference values. INTERPRETATION: Loss of terminal bronchioles is an important structural component of age-related decline in pulmonary function of healthy, non-smoking individuals. FUNDING: Research Foundation-Flanders, KU Leuven, Parker B Francis Foundation, UGent, Canadian Institutes for Health.

Small airways pathology in idiopathic pulmonary fibrosis: a retrospective cohort study.

BACKGROUND: The observation that patients with idiopathic pulmonary fibrosis (IPF) can have higher than normal expiratory flow rates at low lung volumes led to the conclusion that the airways are spared in IPF. This study aimed to re-examine the hypothesis that airways are spared in IPF using a multiresolution imaging protocol that combines multidetector CT (MDCT), with micro-CT and histology. METHODS: This was a retrospective cohort study comparing explanted lungs from patients with severe IPF treated by lung transplantation with a cohort of unused donor (control) lungs. The donor control lungs had no known lung disease, comorbidities, or structural lung injury, and were deemed appropriate for transplantation on review of the clinical files. The diagnosis of IPF in the lungs from patients was established by a multidisciplinary consensus committee according to existing guidelines, and was confirmed by video-assisted thoracic surgical biopsy or by pathological examination of the contralateral lung. The control and IPF groups were matched for age, sex, height, and bodyweight. Samples of lung tissue were compared using the multiresolution imaging approach: a cascade of clinical MDCT, micro-CT, and histological imaging. We did two experiments: in experiment 1, all the lungs were randomly sampled; in experiment 2, samples were selected from regions of minimal and established fibrosis. The patients and donors were recruited from the Katholieke Universiteit Leuven (Leuven, Belgium) and the University of Pennsylvania Hospital (Philadelphia, PA, USA). The study took place at the Katholieke Universiteit Leuven, and the University of British Columbia (Vancouver, BC, Canada). FINDINGS: Between Oct 5, 2009, and July 22, 2016, explanted lungs from patients with severe IPF (n=11), were compared with a cohort of unused donor (control) lungs (n=10), providing 240 samples of lung tissue for comparison using the multiresolution imaging approach. The MDCT specimen scans show that the number of visible airways located between the ninth generation (control 69 [SD 22] versus patients with IPF 105 [33], p=0·0023) and 14th generation (control 9 [6] versus patients with IPF 49 [28], p<0·0001) of airway branching are increased in patients with IPF, which we show by micro-CT is due to thickening of their walls and distortion of their lumens. The micro-CT analysis showed that compared with healthy (control) lung anatomy (mean 5·6 terminal bronchioles per mL [SD 1·6]), minimal fibrosis in IPF tissue was associated with a 57% loss of the terminal bronchioles (mean 2·4 terminal bronchioles per mL [SD 1·0]; p<0·0001), the appearance of fibroblastic foci, and infiltration of the tissue by inflammatory immune cells capable of forming lymphoid follicles. Established fibrosis in IPF tissue had a similar reduction (66%) in the number of terminal bronchioles (mean 1·9 terminal bronchioles per mL [SD 1·4]; p<0·0001) and was dominated by increased airspace size, Ashcroft fibrosis score, and volume fractions of tissue and collagen. INTERPRETATION: Small airways disease is a feature of IPF, with significant loss of terminal bronchioles occuring within regions of minimal fibrosis. On the basis of these findings, we postulate that the small airways could become a potential therapeutic target in IPF. FUNDING: Katholieke Universiteit Leuven, US National Institutes of Health, BC Lung Association, and Genentech.

Effect of a single exacerbation on decline in lung function in COPD.

BACKGROUND: COPD exacerbations are associated with accelerated lung function decline, but whether they are causal is unknown. We evaluated the effect of a single exacerbation on rate of lung function change using data from the 4-year Understanding Potential Long-term Impacts on Function with Tiotropium (UPLIFT®) trial. METHODS: Retrospective analysis of annual rates of decline in FEV1 and FVC before and after a single (and the only) moderate-to-severe exacerbation in patients during UPLIFT® (exacerbator subgroup), compared with changes between the first and second half of the study in a non-exacerbator subgroup. A sensitivity analysis examined annual rates of decline in matched pairs of exacerbators and non-exacerbators. RESULTS: Following the single moderate-to-severe exacerbation, mean annual decline in post-bronchodilator lung function increased compared with the rate of decline before the exacerbation (FEV1 76.5 vs. 39.1 mL/year, p = 0.003; FVC 106.5 vs. 34.7 mL/year, p = 0.011). In non-exacerbators, there were no differences in rates of decline between the first and second halves of the study (post-bronchodilator FEV1 38.2 vs. 41.8 mL/year, FVC 45.3 vs. 43.9 mL/year. Before the single (moderate-to-severe) exacerbation in the exacerbator subgroup, declines in post-bronchodilator FEV1 or FVC were similar to non-exacerbators in the first half of the study; after the single exacerbation they were significantly higher than for non-exacerbators in the second half of the study. The sensitivity analysis showed similar results. CONCLUSION: A single COPD exacerbation may result in significant increase in the rate of decline in lung function.

Morphometric Analysis of Explant Lungs in Cystic Fibrosis.

RATIONALE: After repeated cycles of lung infection and inflammation, patients with cystic fibrosis (CF) evolve to respiratory insufficiency. Although histology and imaging have provided descriptive information, a thorough morphometric analysis of end-stage CF lung disease is lacking. OBJECTIVES: To quantify the involvement of small and large airways in end-stage CF. METHODS: Multidetector computed tomography (MDCT) and micro-CT were applied to 11 air-inflated CF explanted lungs and 7 control lungs to measure, count, and describe the airway and parenchymal abnormalities in end-stage CF lungs. Selected abnormalities were further investigated with thin section histology. MEASUREMENTS AND MAIN RESULTS: On MDCT, CF explanted lungs showed an increased median (interquartile range) number (631 [511-710] vs. 344 [277-349]; P = 0.003) and size of visible airways (cumulative airway diameter 217 cm [209-250] vs. 91 cm [80-105]; P < 0.001) compared with controls. Airway obstruction was seen, starting from generation 6 and increasing to 40 to 50% of airways from generation 9 onward. Micro-CT showed that the total number of terminal bronchioles was decreased (2.9/ml [2.6-4.4] vs. 5.3/ml [4.8-5.7]; P < 0.001); 49% were obstructed, and the cross-sectional area of the open terminal bronchioles was reduced (0.093 mm(2) [0.084-0.123] vs. 0.179 mm(2) [0.140-0.196]; P < 0.001). On micro-CT, 41% of the obstructed airways reopened more distally. This remodeling was confirmed on histological analysis. Parenchymal changes were also seen, mostly in a patchy and peribronchiolar distribution. CONCLUSIONS: Extensive changes of dilatation and obstruction in nearly all airway generations were observed in end-stage CF lung disease.

DNA methylation profiling of non-small cell lung cancer reveals a COPD-driven immune-related signature.

INTRODUCTION: Non-small cell lung cancer (NSCLC) is a heterogeneous disorder consisting of distinct molecular subtypes each characterised by specific genetic and epigenetic profiles. Here, we aimed to identify novel NSCLC subtypes based on genome-wide methylation data, assess their relationship with smoking behaviour, age, COPD, emphysema and tumour histopathology, and identify the molecular pathways underlying each subtype. METHODS: Methylation profiling was performed on 49 pairs of tumour and adjacent lung tissue using Illumina 450 K arrays. Transcriptome sequencing was performed using Illumina HiSeq2000 and validated using expression data from The Cancer Genome Atlas (TCGA). Tumour immune cell infiltration was investigated by immunohistochemistry. RESULTS: Unsupervised hierarchical clustering of tumour methylation data revealed two subgroups characterised by a significant association between cluster membership and presence of COPD (p=0.024). Ontology analysis of genes containing differentially methylated CpGs (false discovery rate, FDR-adjusted p<0.05) revealed that immune genes were strongly enriched in COPD tumours, but not in non-COPD tumours. This COPD-specific immune signature was attributable to methylation changes in immune genes expressed either by tumour cells or tumour-infiltrating immune cells. No such differences were observed in adjacent tissue. Transcriptome profiling similarly revealed that genes involved in the immune response were differentially expressed in COPD tumours (FDR-adjusted p<0.05), an observation that was independently replicated using TCGA data. Immunohistochemistry validated these findings, revealing fewer CD4-positive T lymphocytes in tumours derived from patients with COPD. CONCLUSIONS: Lung tumours of patients with COPD differ from those of patients without COPD, with differentially methylated and expressed genes being mainly involved in the immune response.

Using dynamics of forced expiration to identify COPD where conventional criteria for the FEV1 /FVC ratio do not match.

BACKGROUND AND OBJECTIVE: The definition of chronic obstructive pulmonary disease (COPD) based on a fixed forced expiratory volume in 1 s (FEV1 )/forced vital capacity (FVC) ratio or on the lower limits of FEV1 /FVC of a healthy reference population is the subject of continuous debate. We explored whether dynamics of forced expiratory flow decline on spirometry can identify subjects with and without COPD when the two key diagnostic criteria are discordant. METHODS: Four hundred twenty-three individuals with a history of ≥15 pack-years smoking had pulmonary function measurements conducted. A second-order input-output model was used to describe the dynamics of the forced expiration. The capability of the model parameters to predict presence of disease was explored with a support vector machine classifier. In the discordant individuals, newly classified subjects were validated by other pulmonary function tests. RESULTS: In the non-discordant subjects (n = 370), the second-order model was able to confirm a diagnosis of COPD in 95% of subjects (n = 351). In the discordant individuals (n = 53), the classification by dynamic flow analysis found 28 patients to be healthy whereas 25 patients were still classified as COPD. Hyperinflation, increased airways resistance and reduced dynamic volumes were observed in the newly identified COPD group of discordant subjects. When using non-spirometry-based pulmonary function criteria as a standard for correct diagnoses in the individual discordant subjects, the model allocated 68% (n = 36) of the discordant to a correct diagnosis. CONCLUSIONS: Expiratory flow dynamics can detect airflow limitation and indicate the presence of COPD. In discordant subjects, our methodology allows a better identification of subjects with or without characteristics of COPD.

Acute bronchodilator responses decline progressively over 4 years in patients with moderate to very severe COPD.

BACKGROUND: We previously reported a progressive decline in absolute responses of FEV1 and FVC to a near-maximal dose of 2 different short-acting bronchodilators over 4 years. Since varying host factors and the method of expressing the response may impact the time trend of acute bronchodilator responses, we now examined the potential influence of salient host characteristics on changes in bronchodilator responses over time expressed in different ways. METHODS: As part of the 4-year, placebo-controlled Understanding Potential Long-term Impacts on Function with Tiotropium (UPLIFT) trial, pre- and post-bronchodilator spirometry was performed at baseline and 1 month and every 6 months thereafter. Post-bronchodilator values for FEV1 and FVC were analyzed for subjects completing at least the 1 year visit (Placebo - N = 2463; Tiotropium - N = 2579), stratified by GOLD stage, age, gender and smoking status and expressed as absolute, relative (%) and % predicted changes from pre-bronchodilator values. Annual changes in bronchodilator response were estimated using linear mixed effects models. RESULTS: For all subjects analyzed, FEV1 and FVC bronchodilator responses showed progressive and highly significant (p < 0.0001) declines over 4 years. Declines were generally larger in patients with severe/very severe than mild/moderate airflow obstruction, in older patients (≥65 yrs) and in former than continuing smokers. CONCLUSION: Acute FEV1 and FVC responses to bronchodilators decline significantly over time in COPD patients, whether expressed as absolute, relative or % predicted changes, potentially impacting on the clinical responses to bronchodilator therapy as well as on the annual rate of decline in post-bronchodilator lung function. Clinicaltrials.gov number: NCT00144339.

Acute lung allograft rejection: diagnostic role of probe-based confocal laser endomicroscopy of the respiratory tract.

BACKGROUND: Acute cellular rejection (AR) after lung transplantation may result in significant morbidity and mortality both on the short and long term. Transbronchial biopsy through flexible bronchoscopy is highly sensitive for the diagnosis of AR, but reproducibility of histopathologic interpretation is less convincing. Probe-based confocal laser endomicroscopy (pCLE), a novel imaging tool in the field of respiratory medicine, enables real-time imaging of the pulmonary acini. METHODS: We performed 105 bronchoscopies in lung transplant recipients, combining both transbronchial biopsies and pCLE. We conducted an observational survey for pCLE findings in AR. RESULTS: Calculations for cellularity showed a median cell count (ACA) of 50 (IQR 18 to 120) cells per microscopic field for AR and 10 (IQR 0 to 15) cells per microscopic field for matched controls (p = 0.0004). Cellular autofluorescence in the AR group was 1,163 (± 157) units and 489 (± 101) units for the matched controls (p = 0.0009). Autofluorescent cells were present in 73% (± 10) of the recorded frames in the AR group and in only 42% (± 9) of the recorded frames in the control group (p = 0.03). Contingency analysis for the presence/absence of ACA in the AR group versus the control group showed a sensitivity of 0.93 and a specificity of 0.46 (relative risk = 6.5 [95% CI 0.94 to 44.8], p = 0.01). The consecutive application of 3 pCLE criteria resulted in a sensitivity of 0.93 and a specificity of 0.83 for detection of AR. CONCLUSION: Our observational survey suggests the existence of specific pCLE characteristics in patients with AR. Further efforts are necessary to validate these findings prospectively.

Risk factors and comorbidities in the preclinical stages of chronic obstructive pulmonary disease.

RATIONALE: There is little information about comorbidities and their risk factors in the preclinical stages of chronic obstructive pulmonary disease (COPD). OBJECTIVES: This study aims to investigate the prevalence of premorbid risk factors and comorbid diseases and its association with daily physical activity in subjects detected with COPD by spirometry screening. METHODS: Sixty subjects with preclinical COPD (63 ± 6 yr; 68% [n = 41] male) were compared with 60 smoking control subjects (62 ± 7 yr; 70% [n = 42] male) and 60 never-smoking control subjects (62 ± 6 yr; 57% [n = 34] male). Comorbidities (cardiovascular, metabolic, and musculoskeletal disease) and daily physical activity (by multisensor activity monitor) were measured objectively. MEASUREMENTS AND MAIN RESULTS: The prevalence of premorbid risk factors and comorbid diseases was significantly higher in preclinical COPD compared with age-matched never-smoking control subjects, but was similar to smoking control subjects not suffering from COPD. In preclinical COPD and smoking control subjects, the combination of cardiovascular disease and musculoskeletal disease was the most prevalent (15% [n = 9] and 12% [n = 7], respectively). In a multivariate logistic regression analysis, physical inactivity and smoking were found to be independent risk factors for having greater than or equal to two comorbidities. CONCLUSIONS: Premorbid risk factors and comorbid diseases were more prevalent in the preclinical stages of COPD and smokers without COPD. Physical inactivity and smoking were more strongly associated with the presence of comorbidities compared with airflow obstruction. Clinical trial registered with www.clinicaltrials.gov (NCT 01314807).

Prevention of Exacerbations in Chronic Obstructive Pulmonary Disease: Knowns and Unknowns.

The 2011 recommendations of the Global initiative for chronic Obstructive Lung Disease (GOLD) constituted a major paradigm shift in COPD management since they set 2 major goals for the assessment and management of patients: (1) the reduction of their current level of symptoms (i.e., treat the patient today); and (2) the reduction of their risk of exacerbations (i.e., prevent them tomorrow). Exacerbations are not only an important clinical endpoint in patients with COPD, but they are also a risk factor themselves for additional adverse outcomes since they have been shown to increase the risk for mortality, to accelerate the decline in pulmonary function, and to decrease health status and quality of life. Despite their importance, many unanswered questions related to exacerbations remain. The purpose of this review is to discuss: (1)knowns and unknowns in our current understanding of exacerbations, (2) what known factors increase their risk, and (3) how to best prevent them.

Chronic obstructive pulmonary disease and comorbidities.

Results of epidemiological studies have shown that chronic obstructive pulmonary disease (COPD) is frequently associated with comorbidities, the most serious and prevalent being cardiovascular disease, lung cancer, osteoporosis, muscle weakness, and cachexia. Mechanistically, environmental risk factors such as smoking, unhealthy diet, exacerbations, and physical inactivity or inherent factors such as genetic background and ageing contribute to this association. No convincing evidence has been provided to suggest that treatment of COPD would reduce comorbidities, although some indirect indications are available. Clear evidence that treatment of comorbidities improves COPD is also lacking, although observational studies would suggest such an effect for statins, ß blockers, and angiotensin-converting enzyme blockers and receptor antagonists. Large-scale prospective studies are needed. Reduction of common risk factors seems to be the most powerful approach to reduce comorbidities. Whether reduction of so-called spill-over of local inflammation from the lungs or systemic inflammation with inhaled or systemic anti-inflammatory drugs, respectively, would also reduce COPD-related comorbidities is doubtful.

Computer quantification of airway collapse on forced expiration to predict the presence of emphysema.

BACKGROUND: Spirometric parameters are the mainstay for diagnosis of COPD, but cannot distinguish airway obstruction from emphysema. We aimed to develop a computer model that quantifies airway collapse on forced expiratory flow-volume loops. We then explored and validated the relationship of airway collapse with computed tomography (CT) diagnosed emphysema in two large independent cohorts. METHODS: A computer model was developed in 513 Caucasian individuals with ≥15 pack-years who performed spirometry, diffusion capacity and CT scans to quantify emphysema presence. The model computed the two best fitting regression lines on the expiratory phase of the flow-volume loop and calculated the angle between them. The collapse was expressed as an Angle of collapse (AC) which was then correlated with the presence of emphysema. Findings were validated in an independent group of 340 individuals. RESULTS: AC in emphysema subjects (N = 251) was significantly lower (131° ± 14°) compared to AC in subjects without emphysema (N = 223), (152° ± 10°) (p < 0.0001). Multivariate regression analysis revealed AC as best indicator of visually scored emphysema (R2 = 0.505, p < 0.0001) with little significant contribution of KCO, %predicted and FEV1, %predicted to the total model (total R2 = 0.626, p < 0.0001). Similar associations were obtained when using CT-automated density scores for emphysema assessment. Receiver operating characteristic (ROC) curves pointed to 131° as the best cut-off for emphysema (95.5% positive predictive value, 97% specificity and 51% sensitivity). Validation in a second group confirmed the significant difference in mean AC between emphysema and non-emphysema subjects. When applying the 131° cut-off, a positive predictive value of 95.6%, a specificity of 96% and a sensitivity of 59% were demonstrated. CONCLUSIONS: Airway collapse on forced expiration quantified by a computer model correlates with emphysema. An AC below 131° can be considered as a specific cut-off for predicting the presence of emphysema in heavy smokers.

Annual rates of change in pre- vs. post-bronchodilator FEV1 and FVC over 4 years in moderate to very severe COPD.

While the slope of decline in FEV1 has traditionally been calculated from the post- rather than the pre-bronchodilator measurement in COPD interventional trials, it is not clear whether and to what extent these two slopes differ in symptomatic patients with COPD. Therefore, we used data from the 4-year UPLIFT trial of tiotropium 18 mcg QD vs. placebo to compare annual rates of change in pre- vs. post-bronchodilator FEV1 in 5041 patients with moderate to very severe COPD (mean FEV1 48% pred) in whom the post-bronchodilator FEV1 was measured after 4 inhalations of two different classes of short-acting inhaled bronchodilators at baseline and 1 month and every 6 months post-randomization over 4 years. Linear mixed effects models were used to estimate annual rates of decline in FEV1 and FVC pre- and post-bronchodilator in each treatment group separately, after adjusting for height, gender, smoking status, baseline % predicted FEV1 or FVC, and baseline acute % improvement in lung function. The slopes of the post-bronchodilator FEV1 and FVC were significantly steeper than the pre-bronchodilator slopes regardless of treatment arm (p < 0.001), while the estimated variances of the slopes were similar. Post-bronchodilator increases in FEV1 and FVC diminished progressively and significantly (p < 0.0001) over the 4-year trial, suggesting a possible explanation for the significant differences between the pre- and post-bronchodilator slopes. While the reasons for these differences are not completely clear, they are important to consider when assessing treatment effects on rates of decline in FEV1 and FVC.

Time course of diaphragm function recovery after controlled mechanical ventilation in rats.

Controlled mechanical ventilation (CMV) is known to result in rapid and severe diaphragmatic dysfunction, but the recovery response of the diaphragm to normal function after CMV is unknown. Therefore, we examined the time course of diaphragm function recovery in an animal model of CMV. Healthy rats were submitted to CMV for 24-27 h (n = 16), or to 24-h CMV followed by either 1 h (CMV + 1 h SB, n = 9), 2 h (CMV + 2 h SB, n = 9), 3 h (CMV + 3 h SB, n = 9), or 4-7 h (CMV + 4-7 h SB, n = 9) of spontaneous breathing (SB). At the end of the experiment, the diaphragm muscle was excised for functional and biochemical analysis. The in vitro diaphragm force was significantly improved in the CMV + 3 h SB and CMV + 4-7 h SB groups compared with CMV (maximal tetanic force: +27%, P < 0.05, and +59%, P < 0.001, respectively). This was associated with an increase in the type IIx/b fiber dimensions (P < 0.05). Neutrophil influx was increased in the CMV + 4-7 h SB group (P < 0.05), while macrophage numbers remained unchanged. Markers of protein synthesis (phosphorylated Akt and eukaryotic initiation factor 4E binding protein 1) were significantly increased (±40%, P < 0.001, and ±52%, P < 0.01, respectively) in the CMV + 3 h SB and CMV + 4-7 h SB groups and were positively correlated with diaphragm force (P < 0.05). Finally, also the maximal specific force generation of skinned single diaphragm fibers was increased in the CMV + 4-7 h SB group compared with CMV (+45%, P < 0.05). In rats, reloading the diaphragm for 3 h after CMV is sufficient to improve diaphragm function, while complete recovery occurs after longer periods of reloading. Enhanced muscle fiber dimensions, increased protein synthesis, and improved intrinsic contractile properties of diaphragm muscle fibers may have contributed to diaphragm function recovery.

Impact of exacerbations of cystic fibrosis on muscle strength.

BACKGROUND: Adult patients with cystic fibrosis have peripheral muscle weakness, which is related to exercise intolerance and poor prognosis. The influence of acute exacerbations on muscle strength has been poorly studied. This study aimed to investigate whether quadriceps force (QF), as assessed with an involuntary technique, changes during intravenous antibiotics therapy (IVAT) for an exacerbation. METHODS: QF was measured in 20 patients using twitch stimulation of the femoral nerve at the day of hospitalization (day 1) and at termination (day 14) of the IVAT. Physical activity was monitored during IVAT using a SenseWear armband. Ten stable patients served as control subjects. RESULTS: QF did not change during exacerbation (potentiated twitch force at day 1: 140 ± 42 N, at day 14: 140 ± 47 N), but a decrease was observed in individual patients. Changes in twitch force during exacerbation were correlated with time spent in activities of at least moderate intensity (r = 0.61, p = 0.007). CONCLUSIONS: QF does not systematically decrease during exacerbations of cystic fibrosis. Individual changes in QF are well correlated with daily time spent in activities of at least moderate intensity.

Daily physical activity in subjects with newly diagnosed COPD.

RATIONALE: Information about daily physical activity levels (PAL) in subjects with undiagnosed chronic obstructive pulmonary disease (COPD) is scarce. This study aims to assess PA and to investigate the associations between PA and clinical characteristics in subjects with newly diagnosed COPD. METHODS: Fifty-nine subjects with a new spirometry-based diagnosis of mild (n=38) and moderate (n=21) COPD (63±6 years, 68% male) were matched with 65 smoking controls (62±7 years, 75% male). PA (daily steps, time spent in moderate-to-vigorous intense physical activities (MVPA) and PAL) was measured by accelerometry. Dyspnoea, complete pulmonary function tests, peripheral muscle strength and exercise capacity served as clinical characteristics. RESULTS: PA was significantly lower in COPD versus smoking controls (7986±2648 vs 9765±3078 steps, 64 (27-120) vs 110 (55-164) min of MVPA, 1.49±0.21 vs 1.62±0.24 PAL respectively, all p<0.05). Subjects with COPD with either mild symptoms of dyspnoea (mMRC 1), those with lower diffusion capacity (T(L),co), low 6 min walking distance (6MWD) or low maximal oxygen uptake (VO(2) peak) had significantly lower PA. Multiple regression analysis identified 6 MWD and T(L),co as independent predictors of PA in COPD. CONCLUSIONS: The reduction in PA starts early in the disease, even when subjects are not yet diagnosed with COPD. Inactivity is more pronounced in subjects with mild symptoms of dyspnoea, lower levels of diffusion capacity and exercise capacity.

Perspectives using probe-based confocal laser endomicroscopy of the respiratory tract.

QUESTIONS UNDER STUDY/PRINCIPLES: Although probe-based confocal laser endomicroscopy (pCLE) is on the edge of entering daily practice in gastroenterological endoscopy, findings in the field of respiratory medicine are only rarely reported, keeping pCLE during flexible bronchoscopy as a mere preclinical research tool. Since the endomicroscopic aspects of normal bronchial and alveolar tissue have recently been described, we want to take part in the development of a pCLE glossary, describing the pCLE features of pulmonary pathologies. METHODS: We recruited among patients referred for diagnostic bronchoscopy for pCLE imaging. Images from the central airways were obtained in every patient and alveoloscopy was performed in at least five sub-segments per patient. RESULTS: Using pCLE imaging, we were able to discriminate normal from abnormal endomicroscopical patterns in four respiratory conditions. These findings were matched with classical histopathology. CONCLUSION: Reflecting on our own experience using pCLE imaging, we summarise the present state of knowledge, discuss five clinical cases and discuss current limitations and the future promise of this novel imaging tool.

Variants in the 15q24/25 locus associate with lung function decline in active smokers.

Genetic variation in nicotinic acetylcholine receptor subunit genes (nAChRs) is associated with lung function level and chronic obstructive pulmonary disease (COPD). It is unknown whether these variants also predispose to an accelerated lung function decline. We investigated the association of nAChR susceptibility variants with lung function decline and COPD severity. The rs1051730 and rs8034191 variants were genotyped in a population-based cohort of 1,226 heavy smokers (COPACETIC) and in an independent cohort of 883 heavy smokers, of which 653 with COPD of varying severity (LEUVEN). Participants underwent pulmonary function tests at baseline. Lung function decline was assessed over a median follow-up of 3 years in COPACETIC. Current smokers homozygous for the rs1051730 A-allele or rs8034191 G-allele had significantly greater FEV(1)/FVC decline than homozygous carriers of wild-type alleles (3.3% and 4.3%, p = 0.026 and p = 0.009, respectively). In the LEUVEN cohort, rs1051730 AA-carriers and rs8034191 GG-carriers had a two-fold increased risk to suffer from COPD GOLD IV (OR 2.29, 95% confidence interval [CI] = 1.11-4.75; p = 0.025 and OR = 2.42, 95% [CI] = 1.18-4.95; p = 0.016, respectively). The same risk alleles conferred, respectively, a five- and four-fold increased risk to be referred for lung transplantation because of end-stage COPD (OR = 5.0, 95% [CI] = 1.68-14.89; p = 0.004 and OR = 4.06, 95% [CI] = 1.39-11.88; p = 0.010). In Europeans, variants in nAChRs associate with an accelerated lung function decline in current smokers and with clinically relevant COPD.

Analysis of chronic obstructive pulmonary disease exacerbations with the dual bronchodilator QVA149 compared with glycopyrronium and tiotropium (SPARK): a randomised, double-blind, parallel-group study.

BACKGROUND: We evaluated the effect of dual, longacting inhaled bronchodilator treatment on exacerbations in patients with severe and very severe chronic obstructive pulmonary disease (COPD). METHODS: In this parallel-group study, 2224 patients (aged ≥40 years, Global Initiative for Chronic Obstructive Lung Disease stages III-IV, and one or more moderate COPD exacerbation in the past year) were randomly assigned (1:1:1; via interactive voice response or web system; stratified for smoking status) to once-daily QVA149 (fixed-dose combination of indacaterol 110 µg and glycopyrronium 50 µg), glycopyrronium 50 µg, or tiotropium 18 µg for 64 weeks. Assignment to QVA149 and glycopyrronium was double-blind; tiotropium was open-label. Efficacy was assessed in all patients randomly assigned to treatment groups who received at least one dose of study drug; safety was assessed in all patients who received at least one dose whether or not they were assigned to a group. The primary objective was to show superiority of QVA149 versus glycopyrronium for rate of moderate to severe COPD exacerbations (defined by worsening symptoms and categorised by treatment requirements) during treatment. This completed trial is registered at ClinicalTrials.gov, NCT01120691. FINDINGS: Between April 27, 2010, and July 11, 2012, 741 patients were randomly assigned to receive QVA149, 741 to receive glycopyrronium, and 742 to receive tiotropium (729, 739, and 737 patients, respectively, analysed for efficacy). QVA149 significantly reduced the rate of moderate to severe exacerbations versus glycopyrronium by 12% (annualised rate of exacerbations 0·84 [95% CI 0·75-0·94] vs 0·95 [0·85-1·06]; rate ratio 0·88, 95% CI 0·77-0·99, p=0·038). Adverse events (including exacerbations) were reported for 678 (93%) of 729 patients on QVA149, 694 (94%) of 740 on glycopyrronium, and 686 (93%) of 737 on tiotropium. Incidence of serious adverse events was similar between groups (167 [23%] patients on QVA149, 179 [24%] on glycopyrronium, and 165 [22%] on tiotropium); COPD worsening was the most frequent serious adverse event (107 [15%] patients on QVA149, 116 [16%] on glycopyrronium, 87 [12%] on tiotropium). INTERPRETATIONS: The dual bronchodilator QVA149 was superior in preventing moderate to severe COPD exacerbations compared with the single longacting antimuscarinic bronchodilator glycopyrronium, with concomitant improvements in lung function and health status. These results indicate the potential of dual bronchodilation as a treatment option for patients with severe and very severe COPD. FUNDING: Novartis Pharma AG.

Cost-utility analysis of tiotropium versus usual care in patients with COPD in the UK and Belgium.

OBJECTIVE: To evaluate the cost-utility of adding tiotropium to usual care versus usual care alone for patients with moderate to very severe chronic obstructive pulmonary disease (COPD) in the UK and Belgium. METHODS: A four-state Markov model was developed with three disease severity states (moderate, severe, very severe) and death. Severity was based on post-bronchodilator FEV1 and transitions were based on outcomes of the Understanding Potential Long Term Impacts on Function with Tiotropium (UPLIFT®) trial. Utilities were derived from EQ-5D scores for a subset of UPLIFT® patients. UK costs were evaluated separately for England (E), and for Scotland, Wales and Northern Ireland (SWNI). Belgian (B) costs were obtained from local sources. Uncertainty was assessed by deterministic and probabilistic sensitivity analysis (PSA). RESULTS: Adding tiotropium to usual care resulted in an incremental cost per patient of €969 (B), £796 (E), and £812 (SWNI), and incremental QALYs of 0.052 (B), and 0.051 (E, SWNI). The four-year incremental cost-effectiveness ratios (ICER) were €18,617 (B), £15,567 (E) and £15,890 (SWNI) per QALY. Probability of tiotropium being cost-effective at £30,000 (€50,000) per QALY gained was greater than 60%. CONCLUSIONS: At willingness to pay thresholds of £(€) 30,000 per QALY gained, adding tiotropium to usual care is cost-effective.