Piloting tele-monitoring in COPD: a mixed methods exploration of issues in design and implementation

BACKGROUND

In 2008 NHS Lothian implemented a COPD tele-monitoring service incorporating a touch-screen computer for daily recording of symptoms and weekly oximetry and spirometry measurement. Data were transmitted by secure broadband link to a call centre where trained workers monitored data and contacted clinicians according to an agreed algorithm.

AIMS

To explore the perceptions of patients and professionals about the pilot implementation of the COPD tele-monitoring service.

METHODS

In-depth interviews were undertaken with patients and professionals before and after installation of the tele-monitoring equipment. Interviews were recorded, transcribed and thematically analysed. Data on use of healthcare resources were obtained from primary care records.

RESULTS

Twenty of the 27 patients in the pilot and 25 professionals participated. (n=55 interviews and one focus group). Patients were generally positive about the technology, which they perceived enabled earlier recognition of exacerbations and facilitated access to clinical advice. In contrast, clinicians had concerns about false positive symptom scores, difficulties in interpreting physiological data, overtreatment (reflected in a large increase in antibiotics and steroid prescribing), and an increased workload.

CONCLUSIONS

Tele-monitoring was perceived by patients as improving access to professional care, but raised concerns for clinicians about possible over-treatment and how best to organise services to support the technology.

A combined pulmonary-radiology workshop for visual evaluation of COPD: study design, chest CT findings and concordance with quantitative evaluation

The purposes of this study were: to describe chest CT findings in normal non-smoking controls and cigarette smokers with and without COPD; to compare the prevalence of CT abnormalities with severity of COPD; and to evaluate concordance between visual and quantitative chest CT (QCT) scoring.

METHODS

Volumetric inspiratory and expiratory CT scans of 294 subjects, including normal non-smokers, smokers without COPD, and smokers with GOLD Stage I-IV COPD, were scored at a multi-reader workshop using a standardized worksheet. There were 58 observers (33 pulmonologists, 25 radiologists); each scan was scored by 9-11 observers. Interobserver agreement was calculated using kappa statistic. Median score of visual observations was compared with QCT measurements.

RESULTS

Interobserver agreement was moderate for the presence or absence of emphysema and for the presence of panlobular emphysema; fair for the presence of centrilobular, paraseptal, and bullous emphysema subtypes and for the presence of bronchial wall thickening; and poor for gas trapping, centrilobular nodularity, mosaic attenuation, and bronchial dilation. Agreement was similar for radiologists and pulmonologists. The prevalence on CT readings of most abnormalities (e.g. emphysema, bronchial wall thickening, mosaic attenuation, expiratory gas trapping) increased significantly with greater COPD severity, while the prevalence of centrilobular nodularity decreased. Concordances between visual scoring and quantitative scoring of emphysema, gas trapping and airway wall thickening were 75%, 87% and 65%, respectively.

CONCLUSIONS

Despite substantial inter-observer variation, visual assessment of chest CT scans in cigarette smokers provides information regarding lung disease severity; visual scoring may be complementary to quantitative evaluation.

Inflammatory biomarkers improve clinical prediction of mortality in chronic obstructive pulmonary disease

RATIONALE

Accurate prediction of mortality helps select patients for interventions aimed at improving outcome.

OBJECTIVES

Because chronic obstructive pulmonary disease is characterized by low-grade systemic inflammation, we hypothesized that addition of inflammatory biomarkers to established predictive factors will improve accuracy.

METHODS

A total of 1,843 patients enrolled in the Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints study were followed for 3 years. Kaplan-Meier curves, log-rank analysis, and Cox proportional hazards analyses determined the predictive value for mortality of clinical variables, while C statistics assessed the added discriminative power offered by addition of biomarkers.

MEASUREMENTS AND MAIN RESULTS

At recruitment we measured anthropometrics, spirometry, 6-minute walk distance, dyspnea, BODE index, history of hospitalization, comorbidities, and computed tomography scan emphysema. White blood cell and neutrophil counts, serum or plasma levels of fibrinogen, chemokine ligand 18, surfactant protein D, C-reactive protein, Clara cell secretory protein-16, IL-6 and -8, and tumor necrosis factor-α were determined at recruitment and subsequent visits. A total of 168 of the 1,843 patients (9.1%) died. Nonsurvivors were older and had more severe airflow limitation, increased dyspnea, higher BODE score, more emphysema, and higher rates of comorbidities and history of hospitalizations. The best predictive model for mortality using clinical variables included age, BODE, and hospitalization history (C statistic of 0.686; P < 0.001). One single biomarker (IL-6) significantly improved the C statistic to 0.708, but this was further improved to 0.726 (P = 0.003) by the addition of all biomarkers.

CONCLUSIONS

The addition of a panel of selected biomarkers improves the ability of established clinical variables to predict mortality in chronic obstructive pulmonary disease. Clinical trial registered with www.clinicaltrials.gov (NCT00292552).

Antioxidant pharmacological therapies for COPD

Increased oxidative stress occurs in the lungs and systemically in COPD, which plays a role in many of the pathogenic mechanisms in COPD. Hence, targeting local lung and systemic oxidative stress with agents that modulate the antioxidants/redox system or boost endogenous antioxidants would be a useful therapeutic approach in COPD. Thiol antioxidants (N-acetyl-l-cysteine [NAC] and N-acystelyn, carbocysteine, erdosteine, and fudosteine) have been used to increase lung thiol content. Modulation of cigarette smoke (CS) induced oxidative stress and its consequent cellular changes have also been reported to be effected by synthetic molecules, such as spin traps (α-phenyl-N-tert-butyl nitrone), catalytic antioxidants (superoxide dismutase [ECSOD] mimetics), porphyrins, and lipid peroxidation and protein carbonylation blockers/inhibitors (edaravone and lazaroids/tirilazad). Preclinical and clinical trials have shown that these antioxidants can reduce oxidative stress, affect redox and glutathione biosynthesis genes, and proinflammatory gene expression. In this review the approaches to enhance lung antioxidants in COPD and the potential beneficial effects of antioxidant therapy on the course of the disease are discussed.

Graphene-based nanoplatelets: a new risk to the respiratory system as a consequence of their unusual aerodynamic properties

Graphene is a new nanomaterial with unusual and useful physical and chemical properties. However, in the form of nanoplatelets this new, emerging material could pose unusual risks to the respiratory system after inhalation exposure. The graphene-based nanoplatelets used in this study are commercially available and consist of several sheets of graphene (few-layer graphene). We first derived the respirability of graphene nanoplatelets (GP) from the basic principles of the aerodynamic behavior of plate-shaped particles which allowed us to calculate their aerodynamic diameter. This showed that the nanoplatelets, which were up to 25 μm in diameter, were respirable and so would deposit beyond the ciliated airways following inhalation. We therefore utilized models of pharyngeal aspiration and direct intrapleural installation of GP, as well as an in vitro model, to assess their inflammatory potential. These large but respirable GP were inflammogenic in both the lung and the pleural space. MIP-1α, MCP-1, MIP-2, IL-8, and IL-1β expression in the BAL, the pleural lavage, and cell culture supernatant from THP-1 macrophages were increased with GP exposure compared to controls but not with nanoparticulate carbon black (CB). In vitro, macrophages exposed to GP showed expression of IL-1β. This study highlights the importance of nanoplatelet form as a driver for in vivo and in vitro inflammogenicity by virtue of their respirable aerodynamic diameter, despite a considerable 2-dimensional size which leads to frustrated phagocytosis when they deposit in the distal lungs and macrophages attempt to phagocytose them. Our data suggest that nanoplatelets pose a novel nanohazard and structure-toxicity relationship in nanoparticle toxicology.

The European Respiratory Society spirometry tent: a unique form of screening for airway obstruction

In order to raise public awareness of the importance of early detection of airway obstruction and to enable many people who had not been tested previously to have their lung function measured, the European Lung Foundation and the European Respiratory Society (ERS) organised a spirometry testing tent during the annual ERS Congresses in 2004-2009. Spirometry was performed during the ERS Congresses in volunteers; all participants answered a simple, brief questionnaire on their descriptive characteristics, smoking and asthma. Portable spirometers were freely provided by the manufacturer. Nurses and doctors from pulmonary departments of local hospitals/universities gave their service for free. Lower limit of normal (LLN) and Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria for diagnosing and grading airway obstruction were used. Of 12,448 participants in six congress cities, 10,395 (83.5%) performed acceptable spirometry (mean age 51.0 ± 18.4 yrs; 25.5% smokers; 5.5% asthmatic). Airway obstruction was present in 12.4% of investigated subjects according to LLN criteria and 20.3% according to GOLD criteria. Through multinomial logistic regression analysis, age, smoking habits and asthma were significant risk factors for airway obstruction. Relative risk ratio and 95% confidence interval for LLN stage I, for example, was 2.9 (2.0-4.1) for the youngest age (≤ 19 yrs), 1.9 (1.2-3.0) for the oldest age (≥ 80 yrs), 2.4 (2.0-2.9) for current smokers and 2.8 (2.2-3.6) for reported asthma diagnosis. In addition to being a useful advocacy tool, the spirometry tent represents an unusual occasion for early detection of airway obstruction in large numbers of city residents with an important public health perspective.

Neurological and endocrinological disorders: orphans in chronic obstructive pulmonary disease

Patients with chronic obstructive pulmonary disease (COPD) are often characterised by a range of characteristic co-morbidities that interfere with their pulmonary disease. In addition to a mere association with co-morbidities, a complex pathophysiological interaction and mutual augmentation occurs between COPD and its co-morbidities that may result in disease progression and increased morbidity and mortality. An interdisciplinary approach is required both for diagnosis and treatment to target co-morbidities early in the course of the disease. This review summarizes the current knowledge of the interaction with cerebrovascular disease and endocrinological co-morbidities in COPD patients. There is growing evidence that COPD is an independent risk factor for ischemic stroke, increasing the risk about twofold. Stroke risk in COPD patients increases with the severity of the disease as measured by the degree of airflow limitation. The presence of cardiovascular risk factors is of particular importance for stroke prevention in COPD patients. Endocrinological co-morbidities are also important and many are associated with increased cardiovascular risk. Impaired glucose metabolism ranges from insulin resistance to overt diabetes mellitus, which is a frequent finding and is associated with worse outcome.

Metabolic profiling detects biomarkers of protein degradation in COPD patients

There is a paucity of biomarkers for chronic obstructive pulmonary disease (COPD). Metabolomics were applied to a defined COPD patient cohort from the ECLIPSE study (Evaluation of COPD Longitudinally to Identify Predictive Surrogate End-points). Results were correlated with accepted biomarkers for the disease. Baseline control serum (n=66) and Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage II (n=70), III (n=64) and IV (n=44) COPD patients were analysed by proton nuclear magnetic resonance ((1)H NMR). Liquid chromatography with tandem mass spectrometry (LC-MS/MS) was used to confirm amino acid changes detected by (1)H NMR. Data were correlated with body composition, emphysema and systemic inflammation. (1)H NMR identified decreased lipoproteins, N,N-dimethylglycine, and increased glutamine, phenylalanine, 3-methylhistidine and ketone bodies in COPD patients with decreased branched-chain amino acids (BCAAs) observed in GOLD stage IV patients. BCAAs, their degradation products, 3-methylhistidine, ketone bodies, and triglycerides were correlated negatively with cachexia and positively with systemic inflammation. Emphysema patients also displayed decreased serum creatine, glycine and N,N-dimethylglycine. LC-MS/MS confirmed (1)H NMR findings relating to BCAAs, glutamine and 3-methylhistidine in GOLD stage IV patients. NMR-based metabolomics characterised COPD patients based on systemic effects and lung function parameters. Increased protein turnover occurred in all COPD patients with increased protein degradation in individuals with emphysema and cachexia.

A genome-wide association study of COPD identifies a susceptibility locus on chromosome 19q13

The genetic risk factors for chronic obstructive pulmonary disease (COPD) are still largely unknown. To date, genome-wide association studies (GWASs) of limited size have identified several novel risk loci for COPD at CHRNA3/CHRNA5/IREB2, HHIP and FAM13A; additional loci may be identified through larger studies. We performed a GWAS using a total of 3499 cases and 1922 control subjects from four cohorts: the Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints (ECLIPSE); the Normative Aging Study (NAS) and National Emphysema Treatment Trial (NETT); Bergen, Norway (GenKOLS); and the COPDGene study. Genotyping was performed on Illumina platforms with additional markers imputed using 1000 Genomes data; results were summarized using fixed-effect meta-analysis. We identified a new genome-wide significant locus on chromosome 19q13 (rs7937, OR = 0.74, P = 2.9 × 10(-9)). Genotyping this single nucleotide polymorphism (SNP) and another nearby SNP in linkage disequilibrium (rs2604894) in 2859 subjects from the family-based International COPD Genetics Network study (ICGN) demonstrated supportive evidence for association for COPD (P = 0.28 and 0.11 for rs7937 and rs2604894), pre-bronchodilator FEV(1) (P = 0.08 and 0.04) and severe (GOLD 3&4) COPD (P = 0.09 and 0.017). This region includes RAB4B, EGLN2, MIA and CYP2A6, and has previously been identified in association with cigarette smoking behavior.

Changes in forced expiratory volume in 1 second over time in COPD

BACKGROUND

A key feature of chronic obstructive pulmonary disease (COPD) is an accelerated rate of decline in forced expiratory volume in 1 second (FEV(1)), but data on the variability and determinants of this change in patients who have established disease are scarce.

METHODS

We analyzed the changes in FEV(1) after administration of a bronchodilator over a 3-year period in 2163 patients. A random-coefficient model was used to evaluate possible predictors of both FEV(1) levels and their changes over time.

RESULTS

The mean (±SE) rate of change in FEV(1) was a decline of 33±2 ml per year, with significant variation among the patients studied. The between-patient standard deviation for the rate of decline was 59 ml per year. Over the 3-year study period, 38% of patients had an estimated decline in FEV(1) of more than 40 ml per year, 31% had a decline of 21 to 40 ml per year, 23% had a change in FEV(1) that ranged from a decrease of 20 ml per year to an increase of 20 ml per year, and 8% had an increase of more than 20 ml per year. The mean rate of decline in FEV(1) was 21±4 ml per year greater in current smokers than in current nonsmokers, 13±4 ml per year greater in patients with emphysema than in those without emphysema, and 17±4 ml per year greater in patients with bronchodilator reversibility than in those without reversibility.

CONCLUSIONS

The rate of change in FEV(1) among patients with COPD is highly variable, with increased rates of decline among current smokers, patients with bronchodilator reversibility, and patients with emphysema.

Pulmonary function is associated with distal aortic calcium, not proximal aortic distensibility. MESA lung study

Forced expiratory volume in one second strongly predicts mortality from cardiovascular disease. FEV(1) has been associated with aortic stiffness a strong independent predictor of cardiovascular mortality. However, the anatomical site and possible mechanisms linking aortic stiffness and lung function are unknown. We therefore examined if FEV(1) and CT percent emphysema were associated with calcification of the abdominal aorta or reduced distensibility of the proximal thoracic aorta.The Multi-Ethnic Study of Atherosclerosis (MESA) measured aortic calcification on cardiac and abdominal CT scans and proximal aortic distensibility using magnetic resonance among participants aged 45-84 years without clinical cardiovascular disease. Spirometry was measured following ATS/ERS guidelines and percent emphysema was measured in the lung fields of cardiac CT scans. Multivariate analyses adjusted for age, sex, race/ethnicity and cardiovascular risk factors. Of 1,917 participants with aortic distensibility measures, 13% were current and 38% were former smokers. Eighteen percent had airflow limitation without asthma. FEV(1) was associated with the extent of distal aortic calcification (0.76; 95%CI 0.60-0.97, p = 0.02) but not proximal aortic calcification or proximal aortic distensibility (-0.04 mmHg(-1); 95%CI -0.16-0.09 mmHg(-1), p = 0.60). Percent emphysema was associated with neither measure. FEV(1) was associated with severity of distal aortic calcification where it was present independently of smoking and other cardiovascular risk factors but not with distensibility or calcification of the proximal aorta.

Predicting outcomes from 6-minute walk distance in chronic obstructive pulmonary disease

BACKGROUND

Exercise tolerance is an important clinical aspect of chronic obstructive pulmonary disease that can be easily and reliably measured with the 6-minute walking test (6MWT). To improve the utility of the 6MWT for patient and health care system management, the interpretation of the functional status measure in relation to death and hospitalization should be elucidated.

METHODS

Three-year, prospective, multicenter observational study to evaluate the predictive power of 6MWD for death or exacerbation-related hospitalization and to evaluate the factors that help determine 6MWD.

RESULTS

We measured 6MWD at baseline and annually in 2110 patients with clinically stable Global Initiative for Obstructive Lung Disease (GOLD) stage II-IV COPD and recorded exacerbation-related hospitalizations and all-cause mortality. During the study, 200 patients died and 650 were hospitalized. Using receiver operating characteristics, the best predictive thresholds of the 6MWD were 334 m for increased risk of death and 357 m for exacerbation-related hospitalization (area under the curve 0.67 and 0.60 respectively); however, the discriminatory thresholds, especially for mortality, were influenced by age. The mean (SE) 6MWD declined by 1.6 (1.2) m per year in GOLD II, 9.8 (1.3) m per year in GOLD III, and 8.5 (2.4) m per year in GOLD IV.

CONCLUSION

The 6MWD provides prognostic information that may be useful for identifying high-risk patients with COPD.

Length-dependent retention of carbon nanotubes in the pleural space of mice initiates sustained inflammation and progressive fibrosis on the parietal pleura

The fibrous shape of carbon nanotubes (CNTs) raises concern that they may pose an asbestos-like inhalation hazard, leading to the development of diseases, especially mesothelioma. Direct instillation of long and short CNTs into the pleural cavity, the site of mesothelioma development, produced asbestos-like length-dependent responses. The response to long CNTs and long asbestos was characterized by acute inflammation, leading to progressive fibrosis on the parietal pleura, where stomata of strictly defined size limit the egress of long, but not short, fibers. This was confirmed by demonstrating clearance of short, but not long, CNT and nickel nanowires and by visualizing the migration of short CNTs from the pleural space by single-photon emission computed tomographic imaging. Our data confirm the hypothesis that, although a proportion of all deposited particles passes through the pleura, the pathogenicity of long CNTs and other fibers arises as a result of length-dependent retention at the stomata on the parietal pleura.

Increased platelet activation in patients with stable and acute exacerbation of COPD

RATIONALE

Chronic obstructive pulmonary disease (COPD) is associated with systemic inflammation and cardiovascular disease. Interaction between inflammatory cells and activated platelets is important in the pathogenesis of atherothrombosis and may contribute to cardiovascular risk in patients with COPD.

OBJECTIVES

To assess platelet-monocyte aggregation in patients with COPD and matched controls, and in patients with an acute exacerbation of COPD.

METHODS

18 men with COPD and 16 male controls matched for age and cigarette smoke exposure were recruited. A further 12 patients were investigated during and at least 2 weeks after hospitalisation for an acute exacerbation. Platelet-monocyte aggregation and platelet P-selectin expression were determined using flow cytometry.

RESULTS

Patients with COPD had increased circulating platelet-monocyte aggregates compared with controls (mean (SD) 25.3 (8.3)% vs 19.5 (4.0)%, p=0.01). Platelet-monocyte aggregation was further increased during an acute exacerbation compared with convalescence (32.0 (11.0)% vs 25.5 (6.4)%, p=0.03). Platelet P-selectin expression and soluble P-selectin did not differ between groups.

CONCLUSIONS

Patients with stable COPD have increased circulating platelet-monocyte aggregates compared with well-matched controls. Platelet activation is further increased in patients with COPD during an acute exacerbation. These findings identify a novel mechanism to explain the increased cardiovascular risk in COPD and suggest platelet inhibition as a plausible therapeutic target.

Evaluation of exhaled breath condensate pH as a biomarker for COPD

INTRODUCTION

We assessed the utility of EBC pH as a biomarker in COPD in a large cohort of well-characterised individuals with COPD and control subjects from the Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints (ECLIPSE) study. We also determined short term reproducibility and the response of EBC to oral prednisolone.

METHODS

EBC was collected with R-Tubes(TM), using techniques for sampling and measurement that have been shown to be reproducible.

RESULTS

EBC pH was lower in COPD (n = 676, 7.29 ± SD 0.60) and in smoking controls (n = 31, 7.18 ± 0.85), compared with non-smoking controls (n = 50, 7.59 ± 0.44, p = 0.0008 and 0.0033 respectively), but was not different between COPD and smoking controls. There was no relationship between EBC pH and disease severity, as assessed by the percent predicted FEV(1), nor with airway inflammation as assessed by sputum leukocyte counts. Treatment with 20 mg.day-1 prednisolone for 4 weeks did not change EBC pH.

CONCLUSION

EBC pH is lower in COPD than in healthy control non-smokers, but does not differentiate COPD from smokers without COPD, relate to disease severity or to airway inflammation, and does not respond to corticosteroids. EBC pH therefore does not appear to be a useful biomarker in COPD.

The role of IREB2 and transforming growth factor beta-1 genetic variants in COPD: a replication case-control study

Background

Genetic factors are known to contribute to COPD susceptibility and these factors are not fully understood. Conflicting results have been reported for many genetic studies of candidate genes based on their role in the disease. Genome-wide association studies in combination with expression profiling have identified a number of new candidates including IREB2. A meta-analysis has implicated transforming growth factor beta-1 (TGFbeta1) as a contributor to disease susceptibility.

Methods

We have examined previously reported associations in both genes in a collection of 1017 white COPD patients and 912 non-diseased smoking controls. Genotype information was obtained for seven SNPs in the IREB2 gene, and for four SNPs in the TGFbeta1 gene. Allele and genotype frequencies were compared between COPD cases and controls, and odds ratios were calculated. The analysis was adjusted for age, sex, smoking and centre, including interactions of age, sex and smoking with centre.

Results

Our data replicate the association of IREB2 SNPs in association with COPD for SNP rs2568494, rs2656069 and rs12593229 with respective adjusted p-values of 0.0018, 0.0039 and 0.0053. No significant associations were identified for TGFbeta1.

Conclusions

These studies have therefore confirmed that the IREB2 locus is a contributor to COPD susceptibility and suggests a new pathway in COPD pathogenesis invoking iron homeostasis.