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 FEV1 (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.
In COPD patients, hyperinflation impairs cardiac function. We examined whether lung deflation improves oxygen pulse, a surrogate marker of stroke volume.
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.
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).
In COPD, decreased hyperinflation through lung volume reduction is associated with improved O2 pulse.
cardiac function; hyperinflation; lung volume reduction surgery; oxygen pulse
This study compared visuomotor speed and cognitive flexibility in emphysema patients treated either with standard multidisciplinary medical therapy (MT) or lung volume reduction surgery (LVRS), followed over a 2-year period.
MT patients (n=544) and 542 LVRS patients completed the Trail Making Test (TMT) Parts A and B prior to randomization (baseline). Testing was repeated at 1 and 2 years.
There were no differences on scores for TMT Part A and B between the LVRS and MT groups at baseline or at years 1 and 2. No significant difference between MT and LVRS was noted in terms of overall change in TMT Part A and B over 2 years. The MT group had a significant improvement on TMT-Part A at each followup time compared to baseline (P<.03) but the LVRS group did not. Both the MT and LVRS groups had a significant decline in performance (increase in time to completion) on TMT-Part B when comparing year 1 to baseline (P<.0001).
Emphysema patients who received LVRS or MT as treatment performed similarly on measures of visuomotor speed and flexibility at baseline and 1 and 2 year followup. Both groups showed improvement on visuomotor speed during the first year yet overall cognitive flexibility declined. By the second year neither group had any significant change from baseline. These findings suggest that improvement on visuomotor speed and flexibility, observed in a previous 6-month study of LVRS subjects, was not sustained at 1 and 2 year followup.
Lung volume reduction surgery; Medical therapy; Sequential skills
Rationale: The characterization of young adults who develop late-onset diseases may augment the detection of novel genes and promote new pathogenic insights.
Methods: We analyzed data from 2,500 individuals of African and European ancestry in the COPDGene Study. Subjects with severe, early-onset chronic obstructive pulmonary disease (COPD) (n = 70, age < 55 yr, FEV1 < 50% predicted) were compared with older subjects with COPD (n = 306, age > 64 yr, FEV1 < 50% predicted).
Measurements and Main Results: Subjects with severe, early-onset COPD were predominantly females (66%), P = 0.0004. Proportionally, early-onset COPD was seen in 42% (25 of 59) of African Americans versus 14% (45 of 317) of non-Hispanic whites, P < 0.0001. Other risk factors included current smoking (56 vs. 17%, P < 0.0001) and self-report of asthma (39 vs. 25%, P = 0.008). Maternal smoking (70 vs. 44%, P = 0.0001) and maternal COPD (23 vs. 12%, P = 0.03) were reported more commonly in subjects with early-onset COPD. Multivariable regression analysis found association with African American race, odds ratio (OR), 7.5 (95% confidence interval [CI], 2.3–24; P = 0.0007); maternal COPD, OR, 4.7 (95% CI, 1.3–17; P = 0.02); female sex, OR, 3.1 (95% CI, 1.1–8.7; P = 0.03); and each pack-year of smoking, OR, 0.98 (95% CI, 0.96–1.0; P = 0.03).
Conclusions: These observations support the hypothesis that severe, early-onset COPD is prevalent in females and is influenced by maternal factors. Future genetic studies should evaluate (1) gene-by-sex interactions to address sex-specific genetic contributions and (2) gene-by-race interactions.
chronic obstructive pulmonary disease; female; African Americans
Severe hypoxemia is a major complication of chronic obstructive pulmonary disease (COPD). Long term oxygen therapy is beneficial in hypoxemic COPD patients. However, the clinical and radiographic predictors of hypoxemia and the use of oxygen therapy are not well described. This study aimed to find the correlates of resting hypoxemia and the pattern of oxygen use in moderate to severe COPD patients.
Subjects with GOLD stage II or higher COPD from the first 2500 COPDGene subjects were included in this analysis. All subjects were current or ex-smokers between ages 45 and 80. Severe resting hypoxemia was defined as room air oxygen saturation (SpO2) ≤ 88%. Use of supplemental oxygen therapy was determined by questionnaire.
Eighty-two of 1060 COPD subjects (7.7%) had severe resting hypoxemia. Twenty-one of the 82 (25.6%) were not using continuous supplemental oxygen. Female sex, higher BMI, lower FEV1, and enrollment in Denver were independent risk factors for hypoxemia; emphysema severity on quantitative chest CT scan did not predict hypoxemia. 132 of 971(13.6%) subjects without severe resting hypoxemia were using continuous supplemental oxygen. In non-hypoxemic oxygen users, Denver recruitment, higher BMI, lower FEV1, and more severe dyspnea were associated with the use of continuous oxygen.
A large number of COPD patients without severe hypoxemia were using supplemental oxygen therapy and the pattern of oxygen use was affected by factors other than resting SpO2 and emphysema severity. Longitudinal data will be required to reveal the effects of oxygen therapy in this subgroup.
Hypoxemia; long-term oxygen therapy; COPD; emphysema
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.
chronic obstructive pulmonary disease genetics; chronic obstructive pulmonary disease epidemiology; chronic obstructive pulmonary disease metabolism; genome-wide association study
Rationale: A significant proportion of smokers have lung function impairment characterized by a reduced FEV1 with a preserved FEV1/FVC ratio. These smokers are a poorly characterized group due to their systematic exclusion from chronic obstructive pulmonary disease (COPD) studies.
Objectives: To characterize the clinical, functional, and radiographic features of Global Initiative for Chronic Obstructive Lung Disease (GOLD)-Unclassified (FEV1/FVC ≥ 0.7 and FEV1 < 80% predicted) and lower limits of normal (LLN)-unclassified (FEV1/FVC ≥ LLN and FEV1 < LLN) subjects compared to smokers with normal lung function and subjects with COPD.
Methods: Data from the first 2,500 subjects enrolled in the COPDGene study were analyzed. All subjects had 10 or more pack-years of smoking and were between the ages of 45 and 80 years. Multivariate regression models were constructed to determine the clinical and radiological variables associated with GOLD-Unclassified (GOLD-U) and LLN-Unclassified status. Separate multivariate regressions were performed in the subgroups of subjects with complete radiologic measurement variables available.
Measurements and Main Results: GOLD-U smokers account for 9% of smokers in COPDGene and have increased body mass index (BMI), a disproportionately reduced total lung capacity, and a higher proportion of nonwhite subjects and subjects with diabetes. GOLD-U subjects exhibit increased airway wall thickness compared to smoking control subjects and decreased gas trapping and bronchodilator responsiveness compared to subjects with COPD. When LLN criteria were used to define the “unclassified” group, African American subjects were no longer overrepresented. Both GOLD-U and LLN-Unclassified subjects demonstrated a wide range of lung function impairment, BMI, and percentage of total lung emphysema.
Conclusions: Subjects with reduced FEV1 and a preserved FEV1/FVC ratio are a heterogeneous group with significant symptoms and functional limitation who likely have a variety of underlying etiologies beyond increased BMI.
Clinical trial registered with www.clinicaltrials.gov (NCT000608764).
lung diseases, classification; lung diseases, diagnosis; lung diseases, epidemiology
Patients’ beliefs about the causes of their illness have been associated with emotional adjustment and behavioral outcomes in several medical conditions; however, few studies have examined illness attributions among patients with COPD. In the current study, patterns of patients’ causal attributions for COPD were identified and examined in relation to health behaviors and symptoms.
Three-hundred and ninety-four patients with COPD and ≥10 pack year history of smoking completed a self-report questionnaire that included the Illness Perception Questionnaire- Revised (IPQ-R).
A factor analysis of the IPQ-R cause items using principal axis factoring yielded four individual items (i.e., smoking, heredity, pollution, and personal behavior) and one large factor that was primarily driven by psychological attributions. Ninety-three percent of patients agreed or strongly agreed that smoking was a cause of their COPD. Higher scores on the large IPQ-R factor were associated with reduced quality of life (r=.25, p<.001) and symptoms of anxiety (r=.33, p<.001) and depression (r=.31, p<.001), indicating that patients who attributed their COPD to psychological factors were more likely to have poorer emotional adjustment and quality of life.
Our finding of one large factor with several stand-alone items is in contrast with previous research that has derived a multi-factor structure for the cause items of the IPQ-R in other chronic illness populations. This difference may be due to the importance of smoking, environmental exposures, and heredity in the development of COPD. Future research should expand upon these specific attributions in COPD‥
Chronic Obstructive Pulmonary Disease (COPD); Causal Attributions; Illness Perception Questionnaire- Revised (IPQ-R); Illness Beliefs
Acute exacerbations adversely affect patients with chronic obstructive pulmonary disease (COPD). Macrolide antibiotics benefit patients with a variety of inflammatory airway diseases.
We performed a randomized trial to determine whether azithromycin decreased the frequency of exacerbations in participants with COPD who had an increased risk of exacerbations but no hearing impairment, resting tachycardia, or apparent risk of prolongation of the corrected QT interval.
A total of 1577 subjects were screened; 1142 (72%) were randomly assigned to receive azithromycin, at a dose of 250 mg daily (570 participants), or placebo (572 participants) for 1 year in addition to their usual care. The rate of 1-year follow-up was 89% in the azithromycin group and 90% in the placebo group. The median time to the first exacerbation was 266 days (95% confidence interval [CI], 227 to 313) among participants receiving azithromycin, as compared with 174 days (95% CI, 143 to 215) among participants receiving placebo (P<0.001). The frequency of exacerbations was 1.48 exacerbations per patient-year in the azithromycin group, as compared with 1.83 per patient-year in the placebo group (P=0.01), and the hazard ratio for having an acute exacerbation of COPD per patient-year in the azithromycin group was 0.73 (95% CI, 0.63 to 0.84; P<0.001). The scores on the St. George’s Respiratory Questionnaire (on a scale of 0 to 100, with lower scores indicating better functioning) improved more in the azithromycin group than in the placebo group (a mean [±SD] decrease of 2.8±12.8 vs. 0.6±11.4, P=0.004); the percentage of participants with more than the minimal clinically important difference of −4 units was 43% in the azithromycin group, as compared with 36% in the placebo group (P=0.03). Hearing decrements were more common in the azithromycin group than in the placebo group (25% vs. 20%, P=0.04).
Among selected subjects with COPD, azithromycin taken daily for 1 year, when added to usual treatment, decreased the frequency of exacerbations and improved quality of life but caused hearing decrements in a small percentage of subjects. Although this intervention could change microbial resistance patterns, the effect of this change is not known. (Funded by the National Institutes of Health; ClinicalTrials.gov number, NCT00325897.)
We investigated a large population of patients with chronic obstructive pulmonary disease (COPD) to determine their frequency of medication use and patterns of pharmacotherapy.
Medical and pharmacy claims data were retrospectively analyzed from 19 health plans (>7.79 million members) across the US. Eligible patients were aged ≥40 years, continuously enrolled during July 2004 to June 2005, and had at least one inpatient or at least two outpatient claims coded for COPD. As a surrogate for severity of illness, COPD patients were stratified by complexity of illness using predefined International Classification of Diseases, Ninth Revision, Clinical Modification, Current Procedural Terminology, Fourth Edition, and Healthcare Common Procedure Coding System codes.
A total of 42,565 patients with commercial insurance and 8507 Medicare patients were identified. Their mean age was 54.7 years and 74.8 years, and 48.7% and 46.9% were male, respectively. In total, 66.3% of commercial patients (n = 28,206) were not prescribed any maintenance COPD pharmacotherapy (59.1% no medication; 7.2% inhaled short-acting β2-agonist only). In the Medicare population, 70.9% (n = 6031) were not prescribed any maintenance COPD pharmacotherapy (66.0% no medication; 4.9% short-acting β2-agonist only). A subset of patients classified as high-complexity were similarly undertreated, with 58.7% (5358/9121) of commercial and 68.8% (1616/2350) of Medicare patients not prescribed maintenance COPD pharmacotherapy. Only 18.0% and 9.8% of diagnosed smokers in the commercial and Medicare cohorts had a claim for a smoking cessation intervention and just 16.6% and 23.5%, respectively, had claims for an influenza vaccination.
This study highlights a high degree of undertreatment of COPD in both commercial and Medicare patients, with most patients receiving no maintenance pharmacotherapy or influenza vaccination.
managed care; chronic obstructive pulmonary disease; health care utilization; quality of care
The coexistence of COPD and asthma is widely recognized but has not been well described. This study characterizes clinical features, spirometry, and chest CT scans of smoking subjects with both COPD and asthma.
We performed a cross-sectional study comparing subjects with COPD and asthma to subjects with COPD alone in the COPDGene Study.
119 (13%) of 915 subjects with COPD reported a history of physician-diagnosed asthma. These subjects were younger (61.3 vs 64.7 years old, p = 0.0001) with lower lifetime smoking intensity (43.7 vs 55.1 pack years, p = 0.0001). More African-Americans reported a history of asthma (33.6% vs 15.6%, p < 0.0001). Subjects with COPD and asthma demonstrated worse disease-related quality of life, were more likely to have had a severe COPD exacerbation in the past year, and were more likely to experience frequent exacerbations (OR 3.55 [2.19, 5.75], p < 0.0001). Subjects with COPD and asthma demonstrated greater gas-trapping on chest CT. There were no differences in spirometry or CT measurements of emphysema or airway wall thickness.
Subjects with COPD and asthma represent a relevant clinical population, with worse health-related quality of life. They experience more frequent and severe respiratory exacerbations despite younger age and reduced lifetime smoking history.
Airway hyperresponsiveness; asthma; Chronic obstructive pulmonary disease; emphysema; Exacerbation; Gas-trapping
Rationale: Several family-based studies have identified genetic linkage for lung function and airflow obstruction to chromosome 2q.
Objectives: We hypothesized that merging results of high-resolution single nucleotide polymorphism (SNP) mapping in four separate populations would lead to the identification of chronic obstructive pulmonary disease (COPD) susceptibility genes on chromosome 2q.
Methods: Within the chromosome 2q linkage region, 2,843 SNPs were genotyped in 806 COPD cases and 779 control subjects from Norway, and 2,484 SNPs were genotyped in 309 patients with severe COPD from the National Emphysema Treatment Trial and 330 community control subjects. Significant associations from the combined results across the two case-control studies were followed up in 1,839 individuals from 603 families from the International COPD Genetics Network (ICGN) and in 949 individuals from 127 families in the Boston Early-Onset COPD Study.
Measurements and Main Results: Merging the results of the two case-control analyses, 14 of the 790 overlapping SNPs had a combined P < 0.01. Two of these 14 SNPs were consistently associated with COPD in the ICGN families. The association with one SNP, located in the gene XRCC5, was replicated in the Boston Early-Onset COPD Study, with a combined P = 2.51 × 10−5 across the four studies, which remains significant when adjusted for multiple testing (P = 0.02). Genotype imputation confirmed the association with SNPs in XRCC5.
Conclusions: By combining data from COPD genetic association studies conducted in four independent patient samples, we have identified XRCC5, an ATP-dependent DNA helicase, as a potential COPD susceptibility gene.
emphysema; genetic linkage; metaanalysis; single nucleotide polymorphism
The objective of this study was to test three hypotheses in a sample of individuals with COPD: 1) unsupportive family relationships are associated with psychological distress; 2) psychological distress is associated with smoking status; and 3) unsupportive family relationships are indirectly associated with smoking status via psychological distress.
Cross-sectional data were collected via self-report questionnaires completed by 455 individuals with COPD who had at least a 10 pack-year smoking history. The hypotheses were tested with structural equation modeling.
All three hypotheses were supported. Unsupportive family relationships were associated with psychological distress (β = .67, p < .001), psychological distress was associated with smoking status (β = .40, p < .001), and unsupportive family relationships were indirectly associated with smoking status via psychological distress (β = .27, p < .001).
Results of this study suggest that family relationships are an important factor to include in future longitudinal research that attempts to elucidate social and psychological influences on smoking behavior.
depression; anxiety; smoking; chronic obstructive pulmonary disease
Chronic obstructive pulmonary disease (COPD) is a leading cause of death and 70% of the cost of COPD is due to hospitalizations. Self-reported daily physical activity and health status have been reported as predictors of a hospitalization in COPD but are not routinely assessed.
We tested the hypothesis that self-reported daily physical activity and health status assessed by a simple question were predictors of a hospitalization in a well-characterized cohort of patients with severe emphysema.
Investigators gathered daily physical activity and health status data assessed by a simple question in 597 patients with severe emphysema and tested the association of those patient-reported outcomes to the occurrence of a hospitalization in the following year. Multiple logistic regression analyses were used to determine predictors of hospitalization during the first 12 months after randomization.
The two variables tested in the hypothesis were significant predictors of a hospitalization after adjusting for all univariable significant predictors: >2 h of physical activity per week had a protective effect [odds ratio (OR) 0.60; 95% confidence interval (95% CI) 0.41–0.88] and self-reported health status as fair or poor had a deleterious effect (OR 1.57; 95% CI 1.10–2.23). In addition, two other variables became significant in the multivariate model: total lung capacity (every 10% increase) had a protective effect (OR 0.88; 95% CI 0.78–0.99) and self-reported anxiety had a deleterious effect (OR 1.75; 95% CI 1.13–2.70).
Self-reported daily physical activity and health status are independently associated with COPD hospitalizations. Our findings, assessed by simple questions, suggest the value of patient-reported outcomes in developing risk assessment tools that are easy to use.
Activity of daily living; Chronic obstructive pulmonary disease; Emphysema; Outcomes; Quality of life; Health status; Exercise
Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death among US adults and is projected to be the third by 2020. In anticipation of the increasing burden imposed on healthcare systems and payers by patients with COPD, a means of identifying COPD patients who incur higher healthcare utilization and costs is needed.
This retrospective, cross-sectional analysis of US managed care administrative claims data describes a practical way to identify COPD patients. We analyze 7.79 million members for potential inclusion in the COPD cohort, who were continuously eligible during a 1-year study period. A younger commercial population (7.7 million) is compared with an older Medicare population (0.115 million). We outline a novel approach to stratifying COPD patients using "complexity" of illness, based on occurrence of claims for given comorbid conditions. Additionally, a unique algorithm was developed to identify and stratify COPD exacerbations using claims data.
A total of 42,565 commercial (median age 56 years; 51.4% female) and 8507 Medicare patients (median 75 years; 53.1% female) were identified as having COPD. Important differences were observed in comorbidities between the younger commercial versus the older Medicare population. Stratifying by complexity, 45.0%, 33.6%, and 21.4% of commercial patients and 36.6%, 35.8%, and 27.6% of older patients were low, moderate, and high, respectively. A higher proportion of patients with high complexity disease experienced multiple (≥2) exacerbations (61.7% commercial; 49.0% Medicare) than patients with moderate- (56.9%; 41.6%), or low-complexity disease (33.4%; 20.5%). Utilization of healthcare services also increased with an increase in complexity.
In patients with COPD identified from Medicare or commercial claims data, there is a relationship between complexity as determined by pulmonary and non-pulmonary comorbid conditions and the prevalence of exacerbations and utilization of healthcare services. Identification of COPD patients at highest risk of exacerbations using complexity stratification may facilitate improved disease management by targeting those most in need of treatment.
COPDGeneis a multicenter observational study designed to identify genetic factors associated with COPD. It will also characterize chest CT phenotypes in COPD subjects, including assessment of emphysema, gas trapping, and airway wall thickening. Finally, subtypes of COPD based on these phenotypes will be used in a comprehensive genome-wide study to identify COPD susceptibility genes.
COPDGene will enroll 10,000 smokers with and without COPD across the GOLD stages. Both Non-Hispanic white and African-American subjects are included in the cohort. Inspiratory and expiratory chest CT scans will be obtained on all participants. In addition to the cross-sectional enrollment process, these subjects will be followed regularly for longitudinal studies. A genome-wide association study (GWAS) will be done on an initial group of 4000 subjects to identify genetic variants associated with case-control status and several quantitative phenotypes related to COPD. The initial findings will be verified in an additional 2000 COPD cases and 2000 smoking control subjects, and further validation association studies will be carried out.
COPDGene will provide important new information about genetic factors in COPD, and will characterize the disease process using high resolution CT scans. Understanding genetic factors and CT phenotypes that define COPD will potentially permit earlier diagnosis of this disease and may lead to the development of treatments to modify progression.
Family relationship quality predicts medical outcomes in various health conditions, including stroke, end stage renal disease, and heart failure. Family relationships also influence the onset and course of depression and anxiety disorders. Family may be particularly important in COPD given the high prevalence of depression and anxiety in COPD patients and the association of depression and anxiety with important clinical features of COPD such as dyspnea. The objective of this study was to test three hypotheses in a sample of individuals with COPD: 1) unsupportive family relationships are associated with psychological distress; 2) psychological distress is associated with dyspnea and impairment in health-related quality of life; and 3) unsupportive family relationships are indirectly associated with dyspnea and health-related quality of life via psychological distress. Cross-sectional data were collected via self-report questionnaires completed by 526 individuals with COPD. Structural equation modeling was used to test the hypotheses. All three hypotheses were supported. Unsupportive family relationships were associated with psychological distress, psychological distress was associated with dyspnea and impairment in health-related quality of life, and unsupportive family relationships were indirectly associated with dyspnea and health-related quality of life via psychological distress. If subsequent longitudinal investigations demonstrate that unsupportive family relationships do indeed lead to psychological distress among individuals with COPD, then interventions to improve family relationships of patients with COPD could lead to reductions in psychological distress and, ultimately, to improvements in dyspnea and quality of life.
Pulmonary disease; chronic obstructive; Psychological distress; Health status; Family; Interpersonal relations
Substantial evidence suggests that there is genetic susceptibility to chronic obstructive pulmonary disease (COPD). To identify common genetic risk variants, we performed a genome-wide association study in 2940 cases and 1380 smoking controls with normal lung function. We demonstrate a novel susceptibility locus at 4q22.1 in FAM13A (rs7671167, OR=0.76, P=8.6×10−8) and provide evidence of replication in one case-control and two family-based cohorts (for all studies, combined P=1.2×10−11).
Rationale: In studies that address health-related quality of life (QoL) and survival, subjects who die are usually censored from QoL assessments. This practice tends to inflate the apparent benefits of interventions with a high risk of mortality. Assessing a composite QoL-death outcome is a potential solution to this problem.
Objectives: To determine the effect of lung volume reduction surgery (LVRS) on a composite endpoint consisting of the occurrence of death or a clinically meaningful decline in QoL defined as an increase of at least eight points in the St. George's Respiratory Questionnaire total score from the National Emphysema Treatment Trial.
Methods: In patients with chronic obstructive pulmonary disease and emphysema randomized to receive medical treatment (n = 610) or LVRS (n = 608), we analyzed the survival to the composite endpoint, the hazard functions and constructed prediction models of the slope of QoL decline.
Measurements and Main Results: The time to the composite endpoint was longer in the LVRS group (2 years) than the medical treatment group (1 year) (P < 0.0001). It was even longer in the subsets of patients undergoing LVRS without a high risk for perioperative death and with upper-lobe-predominant emphysema. The hazard for the composite event significantly favored the LVRS group, although it was most significant in patients with predominantly upper-lobe emphysema. The beneficial impact of LVRS on QoL decline was most significant during the 2 years after LVRS.
Conclusions: LVRS has a significant effect on the composite QoL-survival endpoint tested, indicating its meaningful palliative role, particularly in patients with upper-lobe–predominant emphysema.
chronic obstructive pulmonary disease; outcome assessment; palliative care; quality of life; survival; emphysema
Anxiety in patients with chronic obstructive pulmonary disease (COPD) is associated with self-reported disability. The purpose of this study is to determine whether there is an association between anxiety and functional measures, quality of life and dyspnea.
Data from 1828 patients with moderate to severe emphysema enrolled in the National Emphysema Treatment Trial (NETT), collected prior to rehabilitation and randomization, were used in linear regression models to test the association between anxiety symptoms, measured by the Spielberger State Trait Anxiety Inventory (STAI) and: (a) six-minute walk distance test (6 MWD), (b) cycle ergometry peak workload, (c) St. Georges Respiratory Questionnaire (SRGQ), and (d) UCSD Shortness of Breath Questionnaire (SOBQ), after controlling for potential confounders including age, gender, FEV1 (% predicted), DLCO (% predicted), and the Beck Depression Inventory (BDI).
Anxiety was significantly associated with worse functional capacity [6 MWD (B = -0.944, p < .001), ergometry peak workload (B = -.087, p = .04)], quality of life (B = .172, p < .001) and shortness of breath (B = .180, p < .001). Regression coefficients show that a 10 point increase in anxiety score is associated with a mean decrease in 6 MWD of 9 meters, a 1 Watt decrease in peak exercise workload, and an increase of almost 2 points on both the SGRQ and SOBQ.
In clinically stable patients with moderate to severe emphysema, anxiety is associated with worse exercise performance, quality of life and shortness of breath, after accounting for the influence of demographic and physiologic factors known to affect these outcomes.
Assessment of patients with chronic obstructive pulmonary disease (COPD) is important to establish an accurate diagnosis, assist in making therapeutic decisions, measuring outcomes for clinical and research purposes, and determining prognosis. Chest computed tomography (CT) scans are useful in patients who present with airflow limitation and clinical features suggestive of COPD but in whom other diagnoses are being considered. In such cases, a chest CT may indicate another diagnosis. The amount and distribution of emphysema can identify outcomes from lung volume reduction surgery, and chest CT scans are mandatory in assessment of patients for this surgery. Quantitative parameters from chest CT scans have been used to define longitudinal progression of disease. Assessment of patients with COPD for both clinical and research purposes should incorporate a variety of different outcomes. There are outcome measures that have been successfully incorporated in large clinical trials, and the design and outcomes of these trials can be used to plan future clinical investigations in COPD.
chest computed tomography scan; chronic obstructive pulmonary disease; outcomes; health status; exercise capacity
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).
chronic obstructive pulmonary disease; survival; multidimensional index
Various psychological and cognitive difficulties have been documented in patients with emphysema. The aim of this article is to review prior literature on the prevalence of these difficulties in emphysema, as well as identify specific studies demonstrating improvement in these areas after therapy. Traditional therapies such as continuous and intermittent oxygen therapy and comprehensive pulmonary rehabilitation are reviewed. In general, these studies demonstrate reductions in symptoms of depression and anxiety as well as specific improvements in complex attention and verbal fluency. In a more recent study, patients with emphysema who underwent lung volume reduction surgery (LVRS) demonstrated improved psychomotor speed, verbal memory, and naming skills at 6 months compared with patients with emphysema who were in comprehensive rehabilitation only. The patients with emphysema who had LVRS also demonstrated greater decline in depressive symptoms compared with the rehabilitation patients at 6 months. There were no associations between improved neuropsychological tests and changes in depression, exercise tests, pulmonary function, oxygenation, or quality of life scores, and thus the mechanism of behavioral improvement identified in the patients who underwent LVRS remained unclear. Overall, studies suggest that psychological and cognitive improvements occur subsequent to a variety of medical and behavioral treatment therapeutic approaches, and that LVRS appears to have an advantage for some patients with emphysema.
chronic obstructive pulmonary disease; lung volume reduction surgery; neurobehavioral
Comorbidities such as cardiac disease, diabetes mellitus, hypertension, osteoporosis, and psychological disorders are commonly reported in patients with chronic obstructive pulmonary disease (COPD) but with great variability in reported prevalence. Tobacco smoking is a risk factor for many of these comorbidities as well as for COPD, making it difficult to draw conclusions about the relationship between COPD and these comorbidities. However, recent large epidemiologic studies have confirmed the independent detrimental effects of these comorbidities on patients with COPD. On the other hand, many of these comorbidities are now considered to be part of the commonly prevalent nonpulmonary sequelae of COPD that are relevant not only to the understanding of the real burden of COPD but also to the development of effective management strategies.
chronic bronchitis; obstructive lung disease; epidemiology
Pulmonary rehabilitation is an established treatment for patients with chronic lung disease. Benefits include improvement in exercise tolerance, symptoms, and quality of life, with a reduction in the use of health care resources. As an adjunct to surgical programs, such as lung volume reduction surgery, pulmonary rehabilitation plays an important role not just in preparing patients for surgery and facilitating recovery but also in selecting patients and ensuring informed choices about treatment options after optimal medical care. In the National Emphysema Treatment Trial (NETT), subjects completed 6–10 weeks of comprehensive pulmonary rehabilitation before randomization and continued rehabilitation throughout the trial, both at home and with intermittent supervision at either an NETT center or an NETT-certified satellite center. Sessions included a combination of upper and lower extremity exercise, education, and psychosocial support. Before randomization, pulmonary rehabilitation resulted in highly significant changes in exercise capacity, dyspnea, and quality of life. As expected, improvements were significantly greater in those without prior rehabilitation experience. Results for patients completing rehabilitation at satellites were similar to those at NETT centers. Prerandomization pulmonary rehabilitation had a significant effect on outcome after lung volume reduction surgery. NETT identified subgroups with differential outcome by treatment (surgical vs. nonsurgical), defined in part by postrehabilitation maximum exercise capacity. Overall, NETT demonstrated the effectiveness of pulmonary rehabilitation in improving function, symptoms, and health status in a large cohort of patients with advanced emphysema treated in a cross-section of programs in the United States.
emphysema; rehabilitation; chronic obstructive pulmonary disease