Global Initiative on Obstructive Lung Disease (GOLD) classification of lung disease and mortality: findings from the Atherosclerosis Risk in Communities (ARIC) study

The clinical utility of the GOLD classification of COPD disease severity in pulmonary rehabilitation

The Global Initiative for Chronic Obstructive Lung Disease (GOLD) has introduced a four-stage classification of chronic obstructive pulmonary disease (COPD) severity. The present study investigated the discriminatory capacity of the GOLD classification for health status outcomes in patients with COPD. An additional analysis was performed to investigate the discriminatory capacity of a multidimensional staging system, i.e. the Body-Mass Index, Degree of Airflow Obstruction and Dyspnea, and Exercise Capacity Index (BODE index) for the outcome of quality of life. Retrospective analysis was performed on 253 COPD patients (30% stage II, 48% stage III, 22% stage IV), referred for outpatient pulmonary rehabilitation. Pulmonary function, exercise capacity, dyspnoea and quality of life were evaluated. Analyses of variance were used to detect differences between GOLD stages and BODE index quartiles, and scatterplots of individual responses were produced as well. The GOLD classification discriminated between stages for pulmonary function (p<0.001), exercise capacity (p<0.001), dyspnoea (p<0.001) and the activities section (p=0.001) of the St. George Respiratory Questionnaire (SGRQ). The BODE index discriminated between quartiles for the activities section (p<0.001), impacts section (p=0.04) and the total score (p=0.01) of the SGRQ. Scatterplots revealed marked inter-individual variation within each GOLD stage or BODE index quartile, and considerable overlap between stages for all health status outcomes. These findings show that the GOLD classification indeed can be used to discern groups of COPD patients, but due to large inter-individual variability it does not seem adequate as a basis for individual management plans in rehabilitation. The BODE index appeared to discriminate slightly better for quality of life, however, it still leaves a significant part of the variance unexplained.

COPD prevalence in Salzburg, Austria: results from the Burden of Obstructive Lung Disease (BOLD) Study

BACKGROUND

COPD is projected to be the third leading cause of death worldwide by 2020. The Burden of Obstructive Lung Disease initiative was started to measure the prevalence of COPD in a standardized way and to provide estimates of the social and economic burden of disease.

METHODS

We surveyed a gender-stratified, population-based sample of 2,200 adults >or= 40 years of age. The findings of prebronchodilator and postbronchodilator spirometry, as well as information on smoking and reported respiratory disease was recorded. Irreversible airflow obstruction was defined as a postbronchodilator FEV(1)/FVC ratio of < 0.70.

RESULTS

For 1,258 participants with good-quality postbronchodilator spirometry findings, the overall prevalence of COPD at stage I or higher was 26.1%, and was equal in men and women. The prevalence of COPD stage II or higher (FEV(1)/FVC ratio, < 0.7; FEV(1), < 80% predicted) was 10.7%. The prevalence of COPD stage I+, and COPD stage II+, increased with age and cigarette smoking. A doctor diagnosis of COPD was reported by only 5.6% of participants.

CONCLUSION

One quarter of residents of Salzburg County (Austria) who were >or= 40 years of age had at least mild irreversible airflow obstruction. The high prevalence of COPD highlights the impending health-care crisis that will affect many countries as a result of this greatly underappreciated condition.

Nested case-control study on associations between lung function, smoking and mortality in Japanese population

OBJECTIVES

Only a few long-term follow-up studies with a focus on the association between lung function and mortality in the Japanese population have been undertaken. In this study, we examined the associations of lung function, smoking and the results of allergy skin tests with mortality in a longitudinal study of the Japanese population.

METHODS

Baseline measurements were performed on residents of Fukui, Japan in 1972, and a follow-up survey was conducted in 2002. By employing a nested case-control design, 596 cases (deaths) and 596 age and sex-matched controls (survivals) were selected. Lung function was assessed using forced vital capacity (FVC) expressed as the normal percent predicted (FVC %pred) and the ratio of forced expiratory volume in 1 second (FEV(1)) to FVC (FEV(1)/FVC). Allergy skin tests were performed with extracts of house dust, candidia and mixed fungal samples (bronchomycosis). The Brinkman index was used to assess smoking intensity. The Cox proportional hazards model was used to evaluate whether lung function was associated with mortality after adjustment for other potential confounding variables.

RESULTS

Those categorized into the first- or second-lowest quartile of FVC %pred had a higher mortality [hazard ratios (HRs) and 95% confidence intervals (CIs): 2.01 (1.26-3.19) and 1.84 (1.11-3.05)], respectively. On top of these, heavy smoking (BI≥400) was associated with a higher mortality [HR and 95% CI: 1.73 (1.18-2.53)]. There were only weak of associations between the results of allergy skin tests and mortality.

CONCLUSIONS

These results suggest that FVC %pred of lung function and smoking can serve as long-term independent predictors of mortality.

Hospital admission rates among men and women with symptoms of chronic bronchitis and airflow limitation corresponding to the GOLD stages of chronic obstructive pulmonary disease--a population-based study

Chronic obstructive pulmonary disease is a major cause of increased morbidity and mortality. The aim of this study was to investigate hospital admission rates among individuals with symptoms of chronic bronchitis and among those with airflow limitation corresponding to GOLD stages 1-4.

METHOD

Between 1974 and 1992, 22044 middle-aged individuals participated in a health screening, which included spirometry (without broncho-dilation), as well as recording of respiratory symptoms and smoking habits. Information on hospital admissions until 31 December 2002 was obtained from local and national registers. The hospital admission rates due to all causes, obstructive lung disease and cardiovascular disease were analysed among individuals with symptoms of chronic bronchitis and among those with airflow limitation corresponding to GOLD stages 1-4 using ordinal regression with adjustment for age and with individuals with normal lung function and without symptoms of chronic bronchitis as reference group.

RESULTS

Symptoms of chronic bronchitis and GOLD stages 1-4 showed increased hospital admission rates (hospital admission rates due to obstructive lung disease excluded) among smokers of both genders. Furthermore, symptoms of chronic bronchitis showed increased hospital admission rates due to obstructive lung disease among smoking women. There were also increased hospital admission rates due to obstructive lung disease among smokers of GOLD stages 1-4 and increased hospital admission rates due to cardiovascular disease among female smokers of GOLD stage 2.

CONCLUSION

Among smokers, symptoms of chronic bronchitis as well airflow limitation corresponding to GOLD stages 1-4 conveyed a substantial morbidity with increased hospital admission rates due to all causes. The burden of disease is most likely underestimated among individuals with symptoms of chronic bronchitis and chronic obstructive pulmonary disease.

The association between metabolic syndrome and restrictive ventilatory dysfunction in older persons

BACKGROUND

The restrictive, but not the obstructive respiratory dysfunction, is associated with an increased risk of developing type 2 diabetes mellitus. Our aim was to verify in an elderly nondiabetic population whether a restrictive respiratory pattern was associated with a higher prevalence of metabolic syndrome and increased insulin resistance than were obstructive and normal respiratory patterns.

METHODS

We performed a cross-sectional study of 159 consecutive nondiabetic elderly persons attending two social centers. According to their spirometric pattern, volunteers were classified into the following categories: normal spirometry, obstructive (forced expiratory volume in 1 second/forced vital capacity<0.70), and restrictive pattern (forced vital capacity<80% predicted, forced expiratory volume in 1 second/forced vital capacity>or=0.70). Independent correlates of the metabolic syndrome were identified.

RESULTS

The prevalence of metabolic syndrome was higher in restrictive (56%) than in both normal (21.4%, p=.001) and obstructive volunteers (12.9%, p=.001). Insulin resistance, as assessed by the log transformation of the HOmeostasis Model Assessment (HOMA), was higher in restrictive than in obstructive and normal volunteers (1+/-0.6 vs 0.3+/-0.6 and 0.5+/-0.5, p<.001). Restriction was an independent correlate of metabolic syndrome, also after adjustment for waist circumference and body mass index (odds ratio=3.23, 95% confidence interval, 1.23-8.48; p=.01).

CONCLUSION

Restrictive, but not obstructive respiratory pattern, is associated with metabolic syndrome and insulin resistance, and does not only reflect a limitation of ventilation due to visceral obesity. Metabolic abnormalities likely mediate cardiovascular risk in patients with restrictive respiratory impairment.

International variation in the prevalence of COPD (the BOLD Study): a population-based prevalence study

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a growing cause of morbidity and mortality worldwide, and accurate estimates of the prevalence of this disease are needed to anticipate the future burden of COPD, target key risk factors, and plan for providing COPD-related health services. We aimed to measure the prevalence of COPD and its risk factors and investigate variation across countries by age, sex, and smoking status.

METHODS

Participants from 12 sites (n=9425) completed postbronchodilator spirometry testing plus questionnaires about respiratory symptoms, health status, and exposure to COPD risk factors. COPD prevalence estimates based on the Global Initiative for Chronic Obstructive Lung Disease staging criteria were adjusted for the target population. Logistic regression was used to estimate adjusted odds ratios (ORs) for COPD associated with 10-year age increments and 10-pack-year (defined as the number of cigarettes smoked per day divided by 20 and multiplied by the number of years that the participant smoked) increments. Meta-analyses provided pooled estimates for these risk factors.

FINDINGS

The prevalence of stage II or higher COPD was 10.1% (SE 4.8) overall, 11.8% (7.9) for men, and 8.5% (5.8) for women. The ORs for 10-year age increments were much the same across sites and for women and men. The overall pooled estimate was 1.94 (95% CI 1.80-2.10) per 10-year increment. Site-specific pack-year ORs varied significantly in women (pooled OR=1.28, 95% CI 1.15-1.42, p=0.012), but not in men (1.16, 1.12-1.21, p=0.743).

INTERPRETATION

This worldwide study showed higher levels and more advanced staging of spirometrically confirmed COPD than have typically been reported. However, although age and smoking are strong contributors to COPD, they do not fully explain variations in disease prevalence-other factors also seem to be important. Although smoking cessation is becoming an increasingly urgent objective for an ageing worldwide population, a better understanding of other factors that contribute to COPD is crucial to assist local public-health officials in developing the best possible primary and secondary prevention policies for their regions.

Global burden of COPD: risk factors, prevalence, and future trends

Chronic obstructive pulmonary disease (COPD) continues to be an important cause of morbidity, mortality, and health-care costs worldwide. It is a global health issue, with cigarette smoking being an important risk factor universally; other factors, such as exposure to indoor and outdoor air pollution, occupational hazards, and infections, are also important. As the global population ages, the burden of COPD will increase in years to come. Prevalence estimates of the disorder show considerable variability across populations, suggesting that risk factors can affect populations differently. Other advances in our understanding of COPD are increased recognition of the importance of comorbid disease, identification of different COPD phenotypes, and understanding how factors other than lung function affect outcome in our patients. The challenge we will all face in the next few years will be implementation of cost-effective prevention and management strategies to stem the tide of this disease and its cost.

The clinical management in extremely severe COPD

Chronic obstructive pulmonary disease (COPD) affects 6% of the general population and is the fourth-leading cause of death in the United States with severe and very severe disease accounting for 15% and 3% of physician diagnoses of COPD. Guidelines make few recommendations regarding providing the provision of care for the most severe stages of disease, namely Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages III and IV with chronic respiratory failure. The effectiveness of inhaled drug therapy in very severe patients has not been assessed yet. Health care systems in many countries include public funding of long-term oxygen therapy for eligible candidates. Currently, there is little evidence for the use of mechanical ventilatory support in the routine management of hypercapnic patients. Pulmonary rehabilitation should be considered as a significant component of therapy, even in the most severe patients. Although Lung Volume Reduction Surgery has been shown to improve mortality, exercise capacity, and quality of life in selected patients, this modality is associated with significant morbidity and an early mortality rate in the most severe patients. Despite significant progress over the past 25 years, both short- and long-term outcomes remain significantly inferior for lung transplantation relative to other "solid" organ recipients. Nutritional assessment and management is an important therapeutic option in patients with chronic respiratory diseases. Morphine may significantly reduce dyspnoea and does not significantly accelerate death. No consistent improvement in dyspnoea over placebo has been shown with anxiolytics. Supplemental oxygen during exercise reduces exertional breathlessness and improves exercise tolerance of the hypoxaemic patient. Non-invasive ventilation has been used as a palliative treatment to reduce dyspnoea. Hypoxaemic COPD patients, on long-term oxygen therapy, may show reduced health-related quality of life, cognitive function, and depression. Only a small proportion of patients with severe COPD discuss end-of-life issues with their physicians.

Elevated Circulating Plasma Adiponectin in Underweight Patients With COPD

BACKGROUND

Adiponectin is an adipose tissue-derived specific protein that has antiinflammatory as well as anti-atherosclerotic effects. In the United States, many patients with COPD are obese and die of cardiovascular diseases. However, in Japan, patients with COPD are frequently cachexic and die of respiratory failure. This study was designed to investigate the role of adiponectin in these differences in characteristics of COPD.

METHODS

We enrolled normal-weight and underweight male patients with COPD (n = 31; age, 71 +/- 1 years; body mass index [BMI], 20.1 +/- 0.6 kg/m(2)) and age-matched, healthy, male, control subjects (n = 12). The adiponectin levels were measured by enzyme-linked immunosorbent assay. Correlation of adiponectin levels with pulmonary function and serum levels of proinflammatory cytokines (tumor necrosis factor [TNF]-alpha and interleukin-6) were estimated.

RESULTS

Adiponectin levels in patients with COPD were significantly higher than those in control subjects (p<0.01) and inversely correlated with BMI (r = - 0.55, p<0.01). Even in the normal-weight patients with COPD, adiponectin levels were significantly higher than those in control subjects (p<0.01). Adiponectin levels in patients with COPD significantly correlated with percentage of predicted residual volume (r = 0.40, p<0.05). In patients with TNF-alpha levels > 5 pg/mL, there was a significant correlation between plasma adiponectin and serum TNF-alpha levels (r = 0.68, p<0.05).

CONCLUSIONS

Plasma adiponectin levels in patients with COPD were elevated and correlated with body weight loss, hyperinflation, and systemic inflammation. Increased adiponectin may reduce cardiovascular events in underweight patients with COPD.

One hundred years of chronic obstructive pulmonary disease (COPD)

Chronic obstructive pulmonary disease (COPD) is an increasing health problem and one of the leading causes of morbidity and mortality worldwide, but knowledge about its pathogenesis has increased substantially in recent years. The disease results from interaction between individual risk factors (like enzymatic deficiencies) and environmental exposures to noxious agents, like cigarette smoking, occupational dusts, air pollution and infections in childhood. The main mechanisms that may contribute to airflow limitation in COPD are fixed narrowing of small airways, emphysema and luminal obstruction with mucus secretions. COPD is characterised by a chronic inflammatory process in the pulmonary tissue, with a pattern different from bronchial asthma, associated with extrapulmonary effects and is considered now a complex, systemic disease. Optimal therapeutic targeting of COPD depends on a clear understanding of the precise mechanisms of these complex processes and on early and correct evaluation of disease severity. A combination of pharmacological and non-pharmacological approaches is used to treat COPD. Bronchodilators are the mainstay of COPD treatment and can be combined with inhaled corticosteroids for greater efficacy and fewer side effects. The use of LTOT for hypoxemic patients has resulted in increased survival, and expanded drug therapy options have effectively improved dyspnoea and quality of life. Recent studies have documented the benefits of pulmonary rehabilitation. In addition, non-invasive mechanical ventilation offers new alternatives for patients with acute or chronic failure.

Chronic obstructive pulmonary disease in the older adult: what defines abnormal lung function?

BACKGROUND

The Global Initiative on Obstructive Lung Disease stages for chronic obstructive pulmonary disease (COPD) uses a fixed ratio of the post-bronchodilator forced expiratory volume in 1 second (FEV(1))/forced vital capacity (FVC) of 0.70 as a threshold. Since the FEV(1)/FVC ratio declines with age, using the fixed ratio to define COPD may "overdiagnose" COPD in older populations.

OBJECTIVE

To determine morbidity and mortality among older adults whose FEV(1)/FVC is less than 0.70 but more than the lower limit of normal (LLN).

METHODS

The severity of COPD was classified in 4965 participants aged > or =65 years in the Cardiovascular Health Study using these two methods and the age-adjusted proportion of the population who had died or had a COPD-related hospitalisation in up to 11 years of follow-up was determined.

RESULTS

1621 (32.6%) subjects died and 935 (18.8%) had at least one COPD-related hospitalisation during the follow-up period. Subjects (n = 1134) whose FEV(1)/FVC fell between the LLN and the fixed ratio had an increased adjusted risk of death (hazard ratio (HR) 1.3, 95% CI 1.1 to 1.5) and COPD-related hospitalisation (HR 2.6, 95% CI 2.0 to 3.3) during follow-up compared with asymptomatic individuals with normal lung function.

CONCLUSION

In this cohort, subjects classified as "normal" using the LLN but abnormal using the fixed ratio were more likely to die and to have a COPD-related hospitalisation during follow-up. This suggests that a fixed FEV(1)/FVC ratio of <0.70 may identify at-risk patients, even among older adults.

Incidence of chronic obstructive pulmonary disease in a cohort of young adults according to the presence of chronic cough and phlegm

RATIONALE

The few prospective studies aimed at assessing the incidence of chronic obstructive pulmonary disease (COPD) in relation to the presence of chronic cough/phlegm have produced contrasting results.

OBJECTIVES

To assess the incidence of COPD in a cohort of young adults and to test whether chronic cough/phlegm and dyspnea are independent predictors of COPD.

METHODS

An international cohort of 5,002 subjects without asthma (ages 20-44 yr) with normal lung function (FEV(1)/FVC ratio >/= 70%) from 12 countries was followed from 1991-2002 in the frame of the European Community Respiratory Health Survey II. Incident cases of COPD were those who had an FEV(1)/FVC ratio less than 70% at the end of the follow-up, but did not report having had a doctor diagnose asthma during the follow-up.

MAIN RESULTS

The incidence rate of COPD was 2.8 cases/1,000/yr (95% confidence interval [CI], 2.3-3.3). Chronic cough/phlegm was an independent and statistically significant predictor of COPD (incidence rate ratio [IRR], 1.85; 95% CI, 1.17-2.93) after adjusting for smoking habits and other potential confounders, whereas dyspnea was not associated with the disease (IRR = 0.98; 95% CI, 0.64-1.50). Subjects who reported chronic cough/phlegm both at baseline and at the follow-up had a nearly threefold-increased risk of developing COPD with respect to asymptomatic subjects (IRR = 2.88; 95% CI, 1.44-5.79).

CONCLUSIONS

The incidence of COPD is substantial even in young adults. The presence of chronic cough/phlegm identifies a subgroup of subjects with a high risk of developing COPD, independently of smoking habits.

Lung Function Decline and Outcomes in an Adult Population

RATIONALE

Chronic obstructive pulmonary disease (COPD) is an important cause of morbidity and mortality.

OBJECTIVES

To determine risk factors for and outcomes of rapid lung function decline in a cohort of adults in the United States.

METHODS

We analyzed data from 15,536 adults aged 44-66 yr in the Atherosclerosis Risk in Communities study. We used Cox proportional hazard models to determine the risk of rapid lung function decline at 3 yr on mortality and COPD hospitalizations over the subsequent 8 yr.

MEASUREMENTS AND MAIN RESULTS

Of those in the baseline cohort, 13,756 (88.5%) had spirometry at the Year 3 visit. The strongest risk factors for not having a follow-up spirometry were as follows: having Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage 3 or 4 disease at baseline (adjusted odds ratio [OR] 2.8; 95% confidence interval [CI], 2.1-3.8), being black (adjusted OR, 2.4; 95% CI, 2.1-2.7), and being a current smoker (adjusted OR, 1.8; 95% CI, 1.5-2.0). Participants with GOLD stage 3 or 4 disease were also more likely to be in the most rapidly declining lung function quartile (adjusted OR, 3.7; 95% CI, 2.7-5.0). Overall, participants with the most rapidly declining lung function had a modestly increased risk of death (adjusted hazard ratio, 1.4; 95% CI, 1.2-1.7) and time to a COPD-related hospitalization (adjusted hazard ratio, 1.4; 95% CI, 1.2-1.8).

CONCLUSION

Rapid lung function decline was independently associated with a modest increased risk of COPD hospitalizations and deaths.