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1.  Epicardial Adipose Tissue in Patients with Chronic Obstructive Pulmonary Disease 
PLoS ONE  2013;8(6):e65593.
Rationale
Epicardial Adipose Tissue (EAT) volume as determined by chest computed tomography (CT) is an independent marker of cardiovascular events in the general population. COPD patients have an increased risk of cardiovascular disease, however nothing is known about the EAT volume in this population.
Objectives
To assess EAT volume in COPD and explore its association with clinical and physiological variables of disease severity.
Methods
We measured EAT using low-dose CT in 171 stable COPD patients and 70 controls matched by age, smoking history and BMI. We determined blood pressure, cholesterol, glucose and HbA1c levels, microalbuminuria, lung function, BODE index, co-morbidity index and coronary artery calcium score (CAC). EAT volume were compared between groups. Uni and multivariate analyses explored the relationship between EAT volume and the COPD related variables.
Results
COPD patients had a higher EAT volume [143.7 (P25–75, 108.3–196.6) vs 129.1 (P25–75, 91.3–170.8) cm3, p = 0.02)] and the EAT volume was significantly associated with CAC (r = 0.38, p<0.001) and CRP (r = 0.32, p<0.001) but not with microalbuminuria (r = 0.12, p = 0.13). In COPD patients, EAT volume was associated with: age, pack-years, BMI, gender, FEV1%, 6 MWD, MMRC and HTN. Multivariate analysis showed that only pack-years (B = 0.6, 95% CI: 0.5–1.3), BMI (B = 7.8, 95% CI: 5.7–9.9) and 6 MWD (B = −0.2, 95% CI: −0.3–−0.1), predicted EAT volume.
Conclusions
EAT volume is increased in COPD patients and is independently associated with smoking history, BMI and exercise capacity, all modifiable risk factors of future cardiovascular events. EAT volume could be a non-invasive marker of COPD patients at high risk for future cardiovascular events.
doi:10.1371/journal.pone.0065593
PMCID: PMC3675061  PMID: 23762399
2.  Comparison of arterial and venous blood biomarker levels in chronic obstructive pulmonary disease 
F1000Research  2013;2:114.
Purpose: The development of novel biomarkers is an unmet need in chronic obstructive pulmonary disease (COPD). Arterial blood comes directly from the lung and venous blood drains capillary beds of the organ or tissue supplied. We hypothesized that there would be a difference in levels of the biomarkers metalloproteinase 9 (MMP-9), vascular endothelial growth factor A (VEGF-A) and interleukin 6 (IL-6) in arterial compared with venous blood. 
Methods: Radial artery and brachial vein blood samples were taken simultaneously in each of 12 patients with COPD and seven controls with normal lung function. Circulating immunoreactive MMP-9, VEGF-A and IL-6 levels in serum were measured using quantitative enzyme-linked immunosorbent assays. Results were compared using a Student’s paired t test. The study was powered to determine whether significant differences in cytokine levels were present between paired arterial and venous blood samples.  
Results: In the 12 patients with COPD, four were female, and age ranged 53-85 years, mean age 69 years. Three patients in the control group were female, with age range 46-84 years, mean age 64.7 years. In the COPD group, three patients had mild, five moderate and four severe COPD. No significant difference was found between arterial and venous levels of MMP-9, VEGF-A or IL-6. 
Conclusions: In this pilot study, levels of the measured biomarkers in arterial compared with venous blood in both COPD patients and healthy controls did not differ. This suggests that as we continue to chase the elusive biomarker in COPD as a potential tool to measure disease activity, we should focus on venous blood for this purpose.
doi:10.12688/f1000research.2-114.v1
PMCID: PMC3894801  PMID: 24555057
3.  Interstitial Lung Abnormalities and Reduced Exercise Capacity 
Rationale: The relationship between interstitial lung abnormalities (ILA) and exercise capacity has not been comprehensively evaluated.
Objectives: To assess the validity of the 6-minute walk test in subjects with ILA, and to examine the association between ILA and 6-minute walk distance (6MWD).
Methods: Spearman correlation coefficients were used to assess the strength of the relationships between 6MWD and relevant measures of dyspnea, health-related quality of life, and pulmonary function in a cohort of 2,416 people who smoke from the COPDGene study. Unadjusted and adjusted linear and logistic regression models were used to assess the strength of the association between ILA and 6MWD.
Measurements and Main Results: In all subjects, and in those with ILA, 6MWD in COPDGene was associated with relevant clinical and physiologic measures. The mean 6MWD in COPDGene subjects with ILA was 386 m (SD, 128 m), and 82% and 19% of subjects with ILA had 6MWDs less than or equal to 500 and 250 m, respectively. ILA was associated with a reduced 6MWD in univariate (−30 m; 95% confidence interval, −50 to −10; P = 0.004) and multivariate models (−19 m; 95% confidence interval, −33 to −5; P = 0.008). Compared with subjects without ILA, subjects with ILA had an 80% and 77% increase in their odds to have a walk distance limited to less than or equal to 500 and 250 m, respectively. Although these findings were dependent on ILA subtype, they were not limited to those with COPD.
Conclusions: Our study demonstrates that ILA is associated with measurable decrements in the 6MWD of people who smoke.
Clinical trial registered with www.clinicaltrials.gov (NCT 00608764).
doi:10.1164/rccm.201109-1618OC
PMCID: PMC3326424  PMID: 22268134
six-minute walk distance; emphysema; interstitial lung disease; subclinical; idiopathic pulmonary fibrosis
4.  Health effects of the Federal Bureau of Prisons tobacco ban 
Background
Tobacco smoking remains the leading cause of preventable death in America, claiming 450,000 lives annually. Chronic Obstructive Pulmonary Disease, caused by smoking in the vast majority of cases, became the third leading cause of death in the U.S. in 2008. The burden of asthma, often exacerbated by tobacco exposure, has widespread clinical and public health impact. Despite this considerable harm, we know relatively little about the natural history of lung disease and respiratory impairment in adults, especially after smoking cessation.
Methods/Design
Our paper describes the design and rationale for using the 2004 Federal Bureau of Prisons tobacco ban to obtain insights into the natural history of respiratory diseases in adult men and women of different races/ethnicities who are imprisoned in federal medical facilities. We have developed a longitudinal study of new prison arrivals, with data to be collected from each participant over the course of several years, through the use of standardized questionnaires, medical chart reviews, lung function tests, six-minute walk tests, and stored serum for the analysis of present and future biomarkers. Our endpoints include illness exacerbations, medication and health services utilization, lung function, serum biomarkers, and participants’ experience with their health and nicotine addiction.
Discussion
We believe the proposed longitudinal study will make a substantial contribution to the understanding and treatment of respiratory disease and tobacco addiction.
doi:10.1186/1471-2466-12-64
PMCID: PMC3556062  PMID: 23067295
Pulmonary disease; Chronic Obstructive Pulmonary Disease; Asthma; Pathophysiology; Biomarkers; Pulmonary function tests; Tobacco; Nicotine; Addiction; Health services
5.  Longitudinal inspiratory capacity changes in chronic obstructive pulmonary disease 
Respiratory Research  2012;13(1):66.
Background
The changes in inspiratory capacity (IC) over time in chronic obstructive pulmonary disease (COPD) patients are unknown. The Understanding Potential Long-term Impacts on Function with Tiotropium (UPLIFT®) trial included IC measurements.
Methods
IC analysis from UPLIFT® (N = 5992) was performed at 1 and 6 months, and every 6 months through 4 years. Annualized rate of decline in pre- and post-bronchodilator IC and mean differences at each time point were analyzed by mixed-effects models. The relationships between baseline IC and exacerbation rate and mortality were explored using Cox regression analysis.
Results
Baseline characteristics: age, 65 years; 75% men; post-bronchodilator forced expiratory volume in 1 second, 1.32 L (48% predicted); pre- and post-bronchodilator IC, 2.03 and 2.33 L. Mean IC rate of decline (mL/year) was 34 ± 2 (1.7% of baseline) and 50 ± 3 (2.1% of baseline) pre- and post-bronchodilator, respectively, without significant between-group differences. Morning pre-bronchodilator (trough) IC improved with tiotropium versus placebo: 124 mL (1 month), 103 mL (1 year), 107 mL (2 years), 98 mL (3 years), and 97 mL (4 years) (all p < 0.001). Post-bronchodilator improvements were similar between treatment groups. Lower baseline IC values were associated with reduced time to first exacerbation. For the lowest quartile (n = 1413) the values in months were 14.3 (11.7–17.0) for tiotropium and 10.3 (8.8–11.7) for controls (p < 0.01).
Conclusion
IC declines from approximately 34 to 50 mL/year in patients with stage II to IV COPD. Tiotropium treatment does not change the IC decline rate but provides 24-hour improvements in IC sustained over the long term. Trough IC differences suggest that tiotropium provides sustained decrease in end-expiratory lung volume.
doi:10.1186/1465-9921-13-66
PMCID: PMC3443002  PMID: 22866681
COPD; Inspiratory Capacity; Tiotropium
6.  Serum PARC/CCL-18 Concentrations and Health Outcomes in Chronic Obstructive Pulmonary Disease 
Rationale: There are no accepted blood-based biomarkers in chronic obstructive pulmonary disease (COPD). Pulmonary and activation-regulated chemokine (PARC/CCL-18) is a lung-predominant inflammatory protein that is found in serum.
Objectives: To determine whether PARC/CCL-18 levels are elevated and modifiable in COPD and to determine their relationship to clinical end points of hospitalization and mortality.
Methods: PARC/CCL-18 was measured in serum samples from individuals who participated in the ECLIPSE (Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints) and LHS (Lung Health Study) studies and a prednisolone intervention study.
Measurements and Main Results: Serum PARC/CCL-18 levels were higher in subjects with COPD than in smokers or lifetime nonsmokers without COPD (105 vs. 81 vs. 80 ng/ml, respectively; P < 0.0001). Elevated PARC/CCL-18 levels were associated with increased risk of cardiovascular hospitalization or mortality in the LHS cohort and with total mortality in the ECLIPSE cohort.
Conclusions: Serum PARC/CCL-18 levels are elevated in COPD and track clinical outcomes. PARC/CCL-18, a lung-predominant chemokine, could be a useful blood biomarker in COPD.
Clinical trial registered with www.clinicaltrials.gov (NCT 00292552).
doi:10.1164/rccm.201008-1220OC
PMCID: PMC3114051  PMID: 21216880
biomarker; chronic obstructive pulmonary disease; PARC/CCL-18; chemokine
7.  Health status in the TORCH study of COPD: treatment efficacy and other determinants of change 
Respiratory Research  2011;12(1):71.
Background
Little is known about factors that determine health status decline in clinical trials of COPD.
Objectives
To examine health status changes over 3 years in the TORCH study of salmeterol+fluticasone propionate (SFC) vs. salmeterol alone, fluticasone propionate alone or placebo.
Methods
St George's Respiratory Questionnaire (SGRQ) was administered at baseline then every 6 months.
Measurements and Main Results
Data from 4951 patients in 28 countries were available. SFC produced significant improvements over placebo in all three SGRQ domains during the study: (Symptoms -3.6 [95% CI -4.8, -2.4], Activity -2.8 [95% CI -3.9, -1.6], Impacts -3.2 [95% CI -4.3, -2.1]) but the pattern of change over time differed between domains. SGRQ deteriorated faster in patients with Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages III & IV relative to GOLD stage II (p < 0.001). There was no difference in the relationship between deterioration in SGRQ Total score and forced expiratory volume in one second (FEV1) decline (as % predicted) in men and women. Significantly faster deterioration in Total score relative to FEV1 % predicted was seen in older patients (≥ 65 years) and there was an age-related change in Total score that was independent of change in FEV1. The relationship between deterioration in FEV1 and SGRQ did not differ in different world regions, but patients in Asia-Pacific showed a large improvement in score that was unrelated to FEV1 change.
Conclusions
In addition to treatment effects, health status changes in clinical trials may be influenced by demographic and disease-related factors. Deterioration in health status appears to be fastest in older persons and those with severe airflow limitation.
Trial Registration
ClinicalTrials.gov: NCT00268216
doi:10.1186/1465-9921-12-71
PMCID: PMC3117702  PMID: 21627828
COPD; quality of life; health status; lung function
9.  Comorbidities, Patient Knowledge, and Disease Management in a National Sample of Patients with Chronic Obstructive Pulmonary Disease 
The American journal of medicine  2009;122(4):348-355.
Purpose
Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death in the United States but is often under-treated. COPD often overlaps with other conditions such as hypertension and osteoporosis, which are less morbid but which may be treated more aggressively. We evaluated the prevalence of these comorbid conditions and compared testing, patient knowledge, and management in a national sample of patients with COPD.
Methods and Methods
A survey was administered by telephone in 2006 to 1,003 COPD patients to evaluate the prevalence of comorbid conditions, diagnostic testing, knowledge, and management using standardized instruments. The completion rate was 87%.
Results
Among 1,003 patients with COPD, 61% reported moderate or severe dyspnea and 41% a prior hospitalization for COPD. The most prevalent comorbid diagnoses were hypertension (55%), hypercholesterolemia (52%), depression (37%), cataracts (31%) and osteoporosis (28%). Only 10% of respondents knew their FEV1 (95% CI: 8, 12%) compared to 79% who knew their blood pressure (95% CI: 76%, 83%). Seventy-two percent (95% CI: 69%, 75%) reported taking any medication for COPD – usually a short-acting bronchodilator – whereas 87% (95% CI: 84%, 90%) of patients with COPD and hypertension were taking an antihypertensive medication and 72% (95% CI: 68%, 75%) of patients with COPD and hypercholesterolemia were taking a statin.
Conclusion
Although most of these COPD patients in this national sample were symptomatic and many had been hospitalized for COPD, COPD self-knowledge was low and COPD was undertreated compared to generally asymptomatic, less morbid conditions such as hypertension.
doi:10.1016/j.amjmed.2008.09.042
PMCID: PMC2692705  PMID: 19332230
chronic obstructive pulmonary disease; emphysema; chronic bronchitis; asthma; comorbidities
10.  Gender and respiratory factors associated with dyspnea in chronic obstructive pulmonary disease 
Respiratory Research  2007;8(1):18.
Rationale
We had shown that COPD women expressed more dyspnea than men for the same degree of airway obstruction.
Objectives
Evaluate gender differences in respiratory factors associated with dyspnea in COPD patients.
Methods
In a FEV1 % matched population of 100 men and women with COPD we measured: age, MMRC, FEV1, FVC, TLC, IC/TLC, PaO2, PaCO2, DLCO, Pimax, P0.1, Ti/Ttot, BMI, ffmi, 6MWD and VAS scale before and after the test, the Charlson score and the SGRQ. We estimated the association between these parameters and MMRC scores. Multivariate analysis determined the independent strength of those associations.
Results
MMRC correlated with: BMI (men:-0.29, p = 0.04; women:-0.28, p = 0.05), ffmi (men:-0.39, p = 0.01), FEV1 % (men:-0.64, p < 0.001; women:-0.29, p = 0.04), FVC % (men:-0.45, p = 0.001; women:-0.33, p = 0.02), IC/TLC (men:-0.52, p < 0.001; women: -0.27, p = 0.05), PaO2 (men:-0.59, p < 0.001), PaCO2 (men:0.27, p = 0.05), DLCO (men:-0.54, p < 0.001), P0.1/Pimax (men:0.46, p = 0.002; women:0.47, p = 0.005), dyspnea measured with the Visual Analog Scale before (men:0.37, p = 0.04; women:0.52, p = 0.004) and after 6MWD (men:0.52, p = 0.002; women:0.48, p = 0.004) and SGRQ total (men:0.50, p < 0.001; women:0.59, p < 0.001). Regression analysis showed that P0.1/Pimax in women (r2 = 0.30) and BMI, DLCO, PaO2 and P0.1/Pimax in men (r2 = 0.81) were the strongest predictors of MMRC scores.
Conclusion
In mild to severe COPD patients attending a pulmonary clinic, P0.1/Pimax was the unique predictor of MMRC scores only in women. Respiratory factors explain most of the variations of MMRC scores in men but not in women. Factors other than the respiratory ones should be included in the evaluation of dyspnea in women with COPD.
doi:10.1186/1465-9921-8-18
PMCID: PMC1821020  PMID: 17341300
11.  Gender associated differences in determinants of quality of life in patients with COPD: a case series study 
Background
The influence of gender on the expression of COPD has received limited attention. Quality of Life (QoL) has become an important outcome in COPD patients. The aim of our study was to explore factors contributing to gender differences in Quality of Life of COPD patients.
Methods
In 146 men and women with COPD from a pulmonary clinic we measured: Saint George's Respiratory Questionnaire (SGRQ), age, smoking history, PaO2, PaCO2, FEV1, FVC, IC/TLC, FRC, body mass index (BMI), 6 minute walk distance (6MWD), dyspnea (modified MRC), degree of comorbidity (Charlson index) and exacerbations in the previous year. We explored differences between genders using Mann-Whitney U-rank test. To investigate the main determinants of QoL, a multiple lineal regression analysis was performed using backward Wald's criteria, with those variables that significantly correlated with SGRQ total scores.
Results
Compared with men, women had worse scores in all domains of the SGRQ (total 38 vs 26, p = 0.01, symptoms 48 vs 39, p = 0.03, activity 53 vs 37, p = 0.02, impact 28 vs 15, p = 0.01). SGRQ total scores correlated in men with: FEV1% (-0.378, p < 0.001), IC/TLC (-0.368, p = 0.002), PaO2 (-0.379, p = 0.001), PaCO2 (0.256, p = 0.05), 6MWD (-0.327, p = 0.005), exacerbations (0.366, p = 0.001), Charlson index (0.380, p = 0.001) and MMRC (0.654, p < 0.001). In women, the scores correlated only with FEV1% (-0.293, p = 0.013) PaO2 (-0.315, p = 0.007), exacerbations (0.290, p = 0.013) and MMRC (0.628, p < 0.001). Regression analysis (B, 95% CI) showed that exercise capacity (0.05, 0.02 to 0.09), dyspnea (17.6, 13.4 to 21.8), IC/TLC (-51.1, -98.9 to -3.2) and comorbidity (1.7, 0.84 to 2.53) for men and dyspnea (9.7, 7.3 to 12.4) and oxygenation (-0.3, -0.6 to -0.01) for women manifested the highest independent associations with SGRQ scores.
Conclusion
In moderate to severe COPD patients attending a pulmonary clinic, there are gender differences in health status scores. In turn, the clinical and physiological variables independently associated with those scores differed in men and women. Attention should be paid to the determinants of QoL scores in women with COPD.
doi:10.1186/1477-7525-4-72
PMCID: PMC1592076  PMID: 17007639
12.  Markers of exacerbation severity in chronic obstructive pulmonary disease 
Respiratory Research  2006;7(1):74.
Background
Patients with chronic obstructive pulmonary disease (COPD) can experience 'exacerbations' of their conditions. An exacerbation is an event defined in terms of subjective descriptors or symptoms, namely dyspnoea, cough and sputum that worsen sufficiently to warrant a change in medical management. There is a need for reliable markers that reflect the pathological mechanisms that underlie exacerbation severity and that can be used as a surrogate to assess treatment effects in clinical studies. Little is known as to how existing study variables and suggested markers change in both the stable and exacerbation phases of COPD. In an attempt to find the best surrogates for exacerbations, we have reviewed the literature to identify which of these markers change in a consistent manner with the severity of the exacerbation event.
Methods
We have searched standard databases between 1966 to July 2004 using major keywords and terms. Studies that provided demographics, spirometry, potential markers, and clear eligibility criteria were included in this study. Central tendencies and dispersions for all the variables and markers reported and collected by us were first tabulated according to sample size and ATS/ERS 2004 Exacerbation Severity Levels I to III criteria. Due to the possible similarity of patients in Levels II and III, the data was also redefined into categories of exacerbations, namely out-patient (Level I) and in-patient (Levels II & III combined). For both approaches, we performed a fixed effect meta-analysis on each of the reported variables.
Results
We included a total of 268 studies reported between 1979 to July 2004. These studies investigated 142,407 patients with COPD. Arterial carbon dioxide tension and breathing rate were statistically different between all levels of exacerbation severity and between in out- and in-patient settings. Most other measures showed weak relationships with either level or setting, or they had insufficient data to permit meta-analysis.
Conclusion
Arterial carbon dioxide and breathing rate varied in a consistent manner with exacerbation severity and patient setting. Many other measures showed weak correlations that should be further explored in future longitudinal studies or assessed using suggested mathematical modelling techniques.
doi:10.1186/1465-9921-7-74
PMCID: PMC1481583  PMID: 16686949
13.  Finding the Best Thresholds of FEV1 and Dyspnea to Predict 5-Year Survival in COPD Patients: The COCOMICS Study 
PLoS ONE  2014;9(2):e89866.
Background
FEV1 is universally used as a measure of severity in COPD. Current thresholds are based on expert opinion and not on evidence.
Objectives
We aimed to identify the best FEV1 (% predicted) and dyspnea (mMRC) thresholds to predict 5-yr survival in COPD patients.
Design and Methods
We conducted a patient-based pooled analysis of eleven COPD Spanish cohorts (COCOMICS). Survival analysis, ROC curves, and C-statistics were used to identify and compare the best FEV1 (%) and mMRC scale thresholds that predict 5-yr survival.
Results
A total of 3,633 patients (93% men), totaling 15,878 person-yrs. were included, with a mean age 66.4±9.7, and predicted FEV1 of 53.8% (±19.4%). Overall 975 (28.1%) patients died at 5 years. The best thresholds that spirometrically split the COPD population were: mild ≥70%, moderate 56–69%, severe 36–55%, and very severe ≤35%. Survival at 5 years was 0.89 for patients with FEV1≥70 vs. 0.46 in patients with FEV1 ≤35% (H.R: 6; 95% C.I.: 4.69–7.74). The new classification predicts mortality significantly better than dyspnea (mMRC) or FEV1 GOLD and BODE cutoffs (all p<0.001). Prognostic reliability is maintained at 1, 3, 5, and 10 years. In younger patients, survival was similar for FEV1 (%) values between 70% and 100%, whereas in the elderly the relationship between FEV1 (%) and mortality was inversely linear.
Conclusions
The best thresholds for 5-yr survival were obtained stratifying FEV1 (%) by ≥70%, 56–69%, 36–55%, and ≤35%. These cutoffs significantly better predict mortality than mMRC or FEV1 (%) GOLD and BODE cutoffs.
doi:10.1371/journal.pone.0089866
PMCID: PMC3937394  PMID: 24587085
14.  Reliability of FEV1/FEV6 to Diagnose Airflow Obstruction Compared with FEV1/FVC: The PLATINO Longitudinal Study 
PLoS ONE  2013;8(8):e67960.
QUESTION
A 6-second spirometry test is easier than full exhalations. We compared the reliability of the ratio of the Forced expiratory volume in 1 second/Forced expiratory volume in 6 seconds (FEV1/FEV6) to the ratio of the FEV1/Forced vital capacity (FEV1/FVC) for the detection of airway obstruction.
METHODS
The PLATINO population-based survey in individuals aged 40 years and over designed to estimate the prevalence of post-Bronchodilator airway obstruction repeated for the same study participants after 5–9 years in three Latin-American cities.
RESULTS
Using the FEV1/FVC
CONCLUSION
The FEV1/FEV6 is a more reliable index than FEV1/FVC because FVC varies with the duration of the forced exhalation. Reporting FET and FEV1/FEV6
doi:10.1371/journal.pone.0067960
PMCID: PMC3731337  PMID: 23936297
Respiratory medicine  2011;106(1):109-119.
Background
In COPD patients, hyperinflation impairs cardiac function. We examined whether lung deflation improves oxygen pulse, a surrogate marker of stroke volume.
Methods
In 129 NETT patients with cardiopulmonary exercise testing (CPET) and arterial blood gases (ABG substudy), hyperinflation was assessed with residual volume to total lung capacity ratio (RV/TLC), and cardiac function with oxygen pulse (O2 pulse=VO2/HR) at baseline and 6 months. Medical and surgical patients were divided into “deflators” and “non-deflators” based on change in RV/TLC from baseline (ΔRV/TLC). We defined deflation as the ΔRV/TLC experienced by 75% of surgical patients. We examined changes in O2 pulse at peak and similar (iso-work) exercise. Findings were validated in 718 patients who underwent CPET without ABGs.
Results
In the ABG substudy, surgical and medical deflators improved their RV/TLC and peak O2 pulse (median ΔRV/TLC −18.0% vs. −9.3%, p=0.0003; median ΔO2 pulse 13.6% vs. 1.8%, p=0.12). Surgical deflators also improved iso-work O2 pulse (0.53 mL/beat, p=0.04 at 20 watts). In the validation cohort, surgical deflators experienced a greater improvement in peak O2 pulse than medical deflators (mean 18.9% vs. 1.1%). In surgical deflators improvements in O2 pulse at rest and during unloaded pedaling (0.32 mL/beat, p<0.0001 and 0.47 mL/beat, p<0.0001, respectively) corresponded with significant reductions in HR and improvements in VO2. On multivariate analysis, deflators were 88% more likely than non-deflators to have an improvement in O2 pulse (OR 1.88, 95% CI 1.30–2.72, p=0.0008).
Conclusion
In COPD, decreased hyperinflation through lung volume reduction is associated with improved O2 pulse.
doi:10.1016/j.rmed.2011.07.012
PMCID: PMC3233645  PMID: 21843930
cardiac function; hyperinflation; lung volume reduction surgery; oxygen pulse
Respiratory Research  2012;13(1):71.
Background
The relationship between serum biomarkers and clinical expressions of COPD is limited. We planned to further describe this association using markers of inflammation and injury and repair.
Methods
We studied lung function, comorbidities, exercise tolerance, BODE index, and quality of life in 253 COPD patients and recorded mortality over three years. Serum levels of Interleukins 6,8 and16, tumor necrosis factor alpha (TNF α) [inflammatory panel], vascular endothelial growth factor (VEGF), and matrix metalloproteinase 9 (MMP-9) [injury and repair panel] and pulmonary and activation-regulated chemokine (PARC/CCL-18) and monocyte chemotactic protein 1 (MCP-1/CCL2) [chemoattractant panel] were measured. We related the pattern of the biomarker levels to minimal clinically important differences (MCID) using a novel visualization method [ObServed Clinical Association Results (OSCAR) plot].
Results
Levels of the inflammatory markers IL-6, TNF α were higher and those of injury and repair lower (p < 0.01) with more advanced disease (GOLD 1 vs. 4). Using the OSCAR plot, we found that patients in the highest quartile of inflammatory and lowest quartile of injury and repair biomarkers level were more clinically compromised and had higher mortality (p < 0.05).
Conclusions
In COPD, serum biomarkers of inflammation and repair are distinctly associated with important clinical parameters and survival.
doi:10.1186/1465-9921-13-71
PMCID: PMC3493287  PMID: 22906131
Exercise; Inflammation; Phenotypes; Repair; Survival
Cachexia, whether assessed by body mass index (BMI) or fat-free mass index (FFMI), affects a significant proportion of patients with chronic obstructive pulmonary disease (COPD), and is an independent risk factor for increased mortality, increased emphysema, and more severe airflow obstruction. The variable development of cachexia among patients with COPD suggests a role for genetic susceptibility. The objective of the present study was to determine genetic susceptibility loci involved in the development of low BMI and FFMI in subjects with COPD. A genome-wide association study (GWAS) of BMI was conducted in three independent cohorts of European descent with Global Initiative for Chronic Obstructive Lung Disease stage II or higher COPD: Evaluation of COPD Longitudinally to Identify Predictive Surrogate End-Points (ECLIPSE; n = 1,734); Norway-Bergen cohort (n = 851); and a subset of subjects from the National Emphysema Treatment Trial (NETT; n = 365). A genome-wide association of FFMI was conducted in two of the cohorts (ECLIPSE and Norway). In the combined analyses, a significant association was found between rs8050136, located in the first intron of the fat mass and obesity–associated (FTO) gene, and BMI (P = 4.97 × 10−7) and FFMI (P = 1.19 × 10−7). We replicated the association in a fourth, independent cohort consisting of 502 subjects with COPD from COPDGene (P = 6 × 10−3). Within the largest contributing cohort of our analysis, lung function, as assessed by forced expiratory volume at 1 second, varied significantly by FTO genotype. Our analysis suggests a potential role for the FTO locus in the determination of anthropomorphic measures associated with COPD.
doi:10.1165/rcmb.2010-0294OC
PMCID: PMC3266061  PMID: 21037115
chronic obstructive pulmonary disease genetics; chronic obstructive pulmonary disease epidemiology; chronic obstructive pulmonary disease metabolism; genome-wide association study
PLoS ONE  2011;6(9):e24395.
Previous expression quantitative trait loci (eQTL) studies have performed genetic association studies for gene expression, but most of these studies examined lymphoblastoid cell lines from non-diseased individuals. We examined the genetics of gene expression in a relevant disease tissue from chronic obstructive pulmonary disease (COPD) patients to identify functional effects of known susceptibility genes and to find novel disease genes. By combining gene expression profiling on induced sputum samples from 131 COPD cases from the ECLIPSE Study with genomewide single nucleotide polymorphism (SNP) data, we found 4315 significant cis-eQTL SNP-probe set associations (3309 unique SNPs). The 3309 SNPs were tested for association with COPD in a genomewide association study (GWAS) dataset, which included 2940 COPD cases and 1380 controls. Adjusting for 3309 tests (p<1.5e-5), the two SNPs which were significantly associated with COPD were located in two separate genes in a known COPD locus on chromosome 15: CHRNA5 and IREB2. Detailed analysis of chromosome 15 demonstrated additional eQTLs for IREB2 mapping to that gene. eQTL SNPs for CHRNA5 mapped to multiple linkage disequilibrium (LD) bins. The eQTLs for IREB2 and CHRNA5 were not in LD. Seventy-four additional eQTL SNPs were associated with COPD at p<0.01. These were genotyped in two COPD populations, finding replicated associations with a SNP in PSORS1C1, in the HLA-C region on chromosome 6. Integrative analysis of GWAS and gene expression data from relevant tissue from diseased subjects has located potential functional variants in two known COPD genes and has identified a novel COPD susceptibility locus.
doi:10.1371/journal.pone.0024395
PMCID: PMC3174957  PMID: 21949713
PLoS ONE  2011;6(1):e16021.
Rationale
Little is known about gender differences in plasma biomarker levels in patients with chronic obstructive pulmonary disease (COPD).
Hypothesis
There are differences in serum biomarker levels between women and men with COPD.
Objective
Explore gender differences in plasma biomarker levels in patients with COPD and smokers without COPD.
Methods
We measured plasma levels of IL-6, IL-8, IL-16, MCP-1, MMP-9, PARC and VEGF in 80 smokers without COPD (40 males, 40 females) and 152 stable COPD patients (76 males, 76 females) with similar airflow obstruction. We determined anthropometrics, smoking history, lung function, exercise tolerance, body composition, BODE index, co-morbidities and quality of life. We then explored associations between plasma biomarkers levels and the clinical characteristics of the patients and also with the clinical and physiological variables known to predict outcome in COPD.
Results
The plasma biomarkers level explored were similar in men and women without COPD. In contrast, in patients with COPD the median value in pg/mL of IL-6 (6.26 vs 8.0, p = 0.03), IL-16 (390 vs 321, p = 0.009) and VEGF (50 vs 87, p = 0.02) differed between women and men. Adjusted for smoking history, gender was independently associated with IL-16, PARC and VEGF levels. There were also gender differences in the associations between IL-6, IL-16 and VEGF and physiologic variables that predict outcomes.
Conclusions
In stable COPD patients with similar airflow obstruction, there are gender differences in plasma biomarker levels and in the association between biomarker levels and important clinical or physiological variables. Further studies should confirm our findings.
doi:10.1371/journal.pone.0016021
PMCID: PMC3022655  PMID: 21267454
Rationale: The predictive value of longitudinal change in BODE (Body mass index, airflow Obstruction, Dyspnea, and Exercise capacity) index has received limited attention. We hypothesized that decrease in a modified BODE (mBODE) would predict survival in National Emphysema Treatment Trial (NETT) patients.
Objectives: To determine how the mBODE score changes in patients with lung volume reduction surgery versus medical therapy and correlations with survival.
Methods: Clinical data were recorded using standardized instruments. The mBODE was calculated and patient-specific mBODE trajectories during 6, 12, and 24 months of follow-up were estimated using separate regressions for each patient. Patients were classified as having decreasing, stable, increasing, or missing mBODE based on their absolute change from baseline. The predictive ability of mBODE change on survival was assessed using multivariate Cox regression models. The index of concordance was used to directly compare the predictive ability of mBODE and its separate components.
Measurements and Main Results: The entire cohort (610 treated medically and 608 treated surgically) was characterized by severe airflow obstruction, moderate breathlessness, and increased mBODE at baseline. A wide distribution of change in mBODE was seen at follow-up. An increase in mBODE of more than 1 point was associated with increased mortality in surgically and medically treated patients. Surgically treated patients were less likely to experience death or an increase greater than 1 in mBODE. Indices of concordance showed that mBODE change predicted survival better than its separate components.
Conclusions: The mBODE demonstrates short- and intermediate-term responsiveness to intervention in severe chronic obstructive pulmonary disease. Increase in mBODE of more than 1 point from baseline to 6, 12, and 24 months of follow-up was predictive of subsequent mortality. Change in mBODE may prove a good surrogate measure of survival in therapeutic trials in severe chronic obstructive pulmonary disease.
Clinical trial registered with www.clinicaltrials.gov (NCT 00000606).
doi:10.1164/rccm.200709-1383OC
PMCID: PMC2542428  PMID: 18535255
chronic obstructive pulmonary disease; survival; multidimensional index

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