Undiagnosed airflow obstruction: prevalence and implications

Prevalence and Characteristics of Undiagnosed COPD in Adults 40 Years and Older - Reports from the Tunisian Population-Based Burden of Obstructive Lung Disease Study

This study aimed to investigate the underdiagnosis of COPD and its determinants based on the Tunisian Burden of Obstructive Lung Disease study. We collected information on respiratory history symptoms and risk factors for COPD. Post-bronchodilator (Post-BD) FEV1/FVC < the lower limit of normal (LLN) was used to define COPD. Undiagnosed COPD was considered when participants had post-BD FEV1/FVC < LLN but were not given a diagnosis of emphysema, chronic bronchitis or COPD. 730 adults aged ⩾40 years selected from the general population were interviewed, 661 completed spirometry, 35 (5.3%) had COPD and 28 (80%) were undiagnosed with the highest prevalence in women (100%). When compared with patients with an established COPD diagnosis, undiagnosed subjects had a lower education level, milder airway obstruction (Post-BD FEV1 z-score -2.2 vs. -3.7, p < 0.001), fewer occurrence of wheezing (42.9% vs. 100%, p = 0.009), less previous lung function test (3.6% vs. 42.8%, p = 0.019) and less visits to the physician (32.1% vs. 85.7%, p = 0.020) in the past year. Multivaried analysis showed that the probability of COPD underdiagnosis was higher in subjects who had mild to moderate COPD and in those who did not visit a clinician and did not perform a spirometry in the last year. Collectively, our results highlight the need to improve the diagnosis of COPD in Tunisia. Wider use of spirometry should reduce the incidence of undiagnosed COPD. Spirometry should also predominately be performed not only in elderly male smokers but also in younger women in whom the prevalence of underdiagnosis is the highest.

Airflow obstruction among ever-employed U.S. adults aged 18-79 years by industry and occupation: NHANES 2007-2008 to 2011-2012

INTRODUCTION

This study estimated the prevalence of spirometry-defined airflow obstruction by industry and occupation and chronic obstructive pulmonary disease (COPD) among ever-employed U.S. adults.

METHODS

Data came from the National Health and Nutrition Examination Survey (NHANES) 2007-2008 to 2011-2012, a nationally representative study of the non-institutionalized civilian U.S.

POPULATION

Data on respondent's current and/or longest held job were used to create prevalence estimates and adjusted prevalence odds ratios (PORs) for airflow obstruction and COPD.

RESULTS

Among ever-employed U.S. adults, airflow obstruction prevalence was 12.40% and COPD was 3.47%. High airflow obstruction prevalence and significant PORs were reported in mining; manufacturing; construction; and services to buildings industries as well as extraction; bookbinders, prepress, and printing; installers and repairers; and construction occupations.

CONCLUSION

Prevalence of airflow obstruction varies by industry and occupation. Industries and occupations with increased risk were identified using the most current NHANES data including detailed occupations and spirometry.

Chronic respiratory disease: an unrecognized risk factor in dialysis

Background

Few studies have analysed the impact of chronic respiratory disease (CRD) on outcomes in dialysis. We therefore sought to describe patients with CRD and end-stage renal disease and their outcomes after dialysis start, compared with patients without CRD, focusing especially on causes of death, access to renal transplantation and causes of hospital admissions.

Methods

The study included 52 797 adults aged 18 years and older who began dialysis from 2008 to 2013 and are recorded in the French national REIN registry. Survival, specific mortality and access to the waiting list and to renal transplantation were analysed, with adjustment for various comorbidities and consideration of competitive risks. The numbers of hospitalizations and hospital days, together with their causes, were analysed through an indirect link between the REIN database and the national French hospital discharge database.

Results

The frequency of CRD at dialysis start was 12% and was associated with various other comorbidities, including obesity and tobacco use. After adjustment for those comorbidities, CRD remained associated with a higher risk of death [hazard ratio (HR) 1.20, 95% confidence interval (CI) 1.16-1.25]. Patients with CRD were 30% less likely to undergo transplantation (HR 0.67, 95% CI 0.6-0.7) than patients without CRD. Their risk of dying from a respiratory disease was 8.8 times higher; their risk of dying from infection was also higher. Patients with CRD had a higher rate of admissions and more hospital days, for all causes and for every cause, except cancer.

Conclusions

CRD was associated with higher risks of death and hospital admissions and with lower likelihoods of being wait-listed for and undergoing renal transplantation. Increasing clinical awareness by patients and doctors and encouragement of spirometry use should promote more accurate clinical diagnosis and better preventive care for CRD.

Prevalence of undiagnosed airflow obstruction among people with a history of smoking in a primary care setting

Purpose

The purpose of this study was to define the prevalence of undiagnosed airflow obstruction (AO) among subjects with a history of smoking but no previous diagnosis of chronic lung disease. The finding of AO likely represents diagnosis of chronic obstructive pulmonary disease.

Patients

People aged ≥30 years with a history of smoking who attended public outpatient clinics for primary care services were included in this study.

Methods

A cross-sectional survey in five clinics in Hong Kong using the Breathlessness, Cough, and Sputum Scale, the Lung Function Questionnaire, and office spirometry was conducted.

Results

In total, 731 subjects (response rate =97.9%) completed the questionnaires and spirometry tests. Most of the subjects were men (92.5%) in the older age group (mean age =62.2 years; standard deviation =11.7). Of the 731 subjects, 107 had AO, giving a prevalence of 14.6% (95% confidence interval =12.1–17.2); 45 subjects with AO underwent a postbronchodilator test. By classifying the severity of chronic obstructive pulmonary disease using the Global Initiative for Chronic Obstructive Lung Disease, 27 (60%) were considered to be in mild category and 18 (40%) in moderate category. None of them belonged to the severe or very severe category. The total score of Lung Function Questionnaire showed that majority of the subjects with AO also had chronic cough, wheezing attack, or breathlessness, although most did not show any acute respiratory symptoms in accordance with the Breathlessness, Cough, and Sputum Scale. Diagnosis of AO was positively associated with the number of years of smoking (odds ratio =1.044, P=0.035) and being normal or underweight (odds ratio =1.605, P=0.046). It was negatively associated with a history of hypertension (odds ratio =0.491, P=0.003).

Conclusion

One-seventh of smokers have undiagnosed AO. Spirometry screening of smokers should be considered in order to diagnose AO at an early stage, with an emphasis on smoking cessation.

Undiagnosed Obstructive Lung Disease in the United States. Associated Factors and Long-term Mortality

RATIONALE

Understanding factors associated with undiagnosed obstructive lung disease and its impact on mortality could inform the ongoing discussions about benefits and risks of screening and case finding.

OBJECTIVES

To define factors associated with undiagnosed obstructive lung disease and its long-term mortality.

METHODS

Cross-sectional analysis of participants, aged 20 to 79 years, in two National Health and Nutritional Examination Surveys (NHANES), NHANES III (1988-1994) and NHANES 2007-2012, with longitudinal follow-up of NHANES III participants.

MEASUREMENTS AND MAIN RESULTS

We classified participants with spirometry-confirmed obstructive disease, based on the fixed ratio definition (FEV1/FVC < 0.7), as "diagnosed" (physician diagnosis of either asthma or chronic obstructive pulmonary disease), and "undiagnosed" (no recorded physician diagnosis). For the longitudinal analysis of NHANES III participants, mortality was the outcome of interest. We tested the contribution of self-reported health status and comorbidity burden (exposure) to the odds of being undiagnosed using logistic models adjusted for demographics, smoking status, and lung function. We estimated hazard ratios (HRs) for all-cause mortality for diagnosed and undiagnosed subjects participating in NHANES III who had spirometry using Cox- proportional regression analysis. Among those with spirometry-defined obstruction, 71.2% (SE, 1.8) in NHANES III and 72.0% (SE, 1.9) in NHANES 2007-2012 were undiagnosed. In multivariate models, undiagnosed obstructive disease was consistently associated in both surveys with self-reported good/excellent health status, lower comorbidity burden, higher lung function, and being of racial/ethnic minority. Among NHANES III participants (median follow up, 14.5 yr), both undiagnosed (HR, 1.23; 95% confidence interval, 1.08-1.40) and correctly diagnosed participants (HR, 1.74; 95% confidence interval, 1.45-2.09) had higher risk for all-cause mortality than participants without obstruction.

CONCLUSIONS

Undiagnosed obstructive lung disease is common among American adults and remained unchanged over 2 decades. Although undiagnosed subjects appear healthier than those with a diagnosis, their risk of death was increased compared with subjects without obstruction. These findings need to be considered when judging the implications of case-finding programs for obstructive lung disease.

Chronic obstructive pulmonary disease and health-related quality of life in the 2009 Texas Behavioral Risk Factor survey

INTRODUCTION

Individuals with chronic obstructive pulmonary disease (COPD) experience irreversible airflow obstruction, dyspnea, coughing, and fatigue. One of the goals of treating individuals with COPD is to improve their quality of life. The aim of this research was to evaluate the 2009 Texas Behavioral Risk Factor Surveillance System (BRFSS) as a method for surveillance of COPD by identifying factors associated with impaired health-related quality of life (HRQoL) among respondents with COPD as well as comment on differences between the COPD and non-COPD population in a state representative sample.

METHOD

Data from 348 COPD respondents were obtained from the 2009 Texas BRFSS. The Andersen behavior model was used to categorize variables as predisposing characteristics, health behaviors, and health service utilization. Self-rated health (SRH) was the HRQoL indicator used in this analysis. Chi-square tests were used to examine differences between COPD and non-COPD respondents. The relation between SRH and risk factors were modeled using domain analysis and logistic regressions. All analyses incorporated the sample weights to be representative of the state population.

RESULTS

Adults with COPD reported significantly worse SRH than adults who did not have COPD (p < .001). Among respondents with COPD, the predisposing characteristics associated with impaired HRQoL were obesity, education, and asthma; the health practices and service utilization factors associated with HRQoL included smoking, physical inactivity, having a health plan, and the inability to see a doctor because of costs.

CONCLUSIONS

The Texas COPD population experienced increased risk of impaired SRH compared with the non-COPD population. The findings from our population-level survey study are similar to results observed at the clinical level.

Mortality in COPD: causes, risk factors, and prevention

Chronic obstructive pulmonary disease (COPD) is a leading and increasing cause of death, the extent of which is underestimated as a consequence of underdiagnosis and underreporting on death certificates. Data from large trials, such as the Lung Health Study, Towards a Revolution in COPD Health (TORCH), Understanding Potential Long-term Impacts on Function with Tiotropium (UPLIFT), European Respiratory Society Study on Chronic Obstructive Pulmonary Disease (EUROSCOP), and Inhaled Steroids in Obstructive Lung Disease (ISOLDE), have shown that the causes of death in patients with mild COPD are predominantly cancer and cardiovascular disease, but as COPD severity increases, deaths due to non-malignant respiratory disease are increasingly common. In practice, mortality of patients with COPD can be predicted by a variety of measures including: forced expiratory volume in one second (FEV(1)), the ratio of inspiratory and total lung capacities, exercise capacity, dyspnea scores, and composite indices such as the body-mass index (B), degree of airflow obstruction (O), degree of functional dyspnea (D), and exercise capacity (E) (BODE) index. Smoking cessation improves survival in COPD patients, and in select patients with advanced disease, oxygen therapy, lung volume reduction surgery, or lung transplantation may also improve survival.

Lung function in young adults predicts airflow obstruction 20 years later

OBJECTIVE

The burden of obstructive lung disease is increasing, yet there are limited data on its natural history in young adults. To determine in a prospective cohort of generally healthy young adults the influence of early adult lung function on the presence of airflow obstruction in middle age.

METHODS

A longitudinal study was performed of 2496 adults who were 18 to 30 years of age at entry, did not report having asthma, and returned at year 20. Airflow obstruction was defined as an forced expiratory volume in 1 second/forced vital capacity ratio less than the lower limit of normal.

RESULTS

Airflow obstruction was present in 6.9% and 7.8% of participants at years 0 and 20, respectively. Less than 10% of participants with airflow obstruction self-reported chronic obstructive pulmonary disease. In cross-sectional analyses, airflow obstruction was associated with less education, smoking, and self-reported chronic obstructive pulmonary disease. Low forced expiratory volume in 1 second, forced expiratory volume in 1 second/forced vital capacity ratio, and airflow obstruction in young adults were associated with low lung function and airflow obstruction 20 years later. Of those with airflow obstruction at year 0, 52% had airflow obstruction 20 years later. The forced expiratory volume in 1 second/forced vital capacity at year 0 was highly predictive of airflow obstruction 20 years later (c-statistic 0.91; 95% confidence interval, 0.89-0.93). The effect of cigarette smoking on lung function decline with age was most evident in young adults with preexisting airflow obstruction.

CONCLUSION

Airflow obstruction is mostly unrecognized in young and middle-aged adults. Low forced expiratory volume in 1 second, low forced expiratory volume in 1 second/forced vital capacity ratio, airflow obstruction in young adults, and smoking are highly predictive of low lung function and airflow obstruction in middle age.

Systems biology coupled with label-free high-throughput detection as a novel approach for diagnosis of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a treatable and preventable disease state, characterised by progressive airflow limitation that is not fully reversible. Although COPD is primarily a disease of the lungs there is now an appreciation that many of the manifestations of disease are outside the lung, leading to the notion that COPD is a systemic disease. Currently, diagnosis of COPD relies on largely descriptive measures to enable classification, such as symptoms and lung function. Here the limitations of existing diagnostic strategies of COPD are discussed and systems biology approaches to diagnosis that build upon current molecular knowledge of the disease are described. These approaches rely on new 'label-free' sensing technologies, such as high-throughput surface plasmon resonance (SPR), that we also describe.

Do family physicians' records fit guideline diagnosed COPD?

BACKGROUND

In family practice, chronic obstructive pulmonary disease (COPD) is usually not diagnosed until clinically apparent and of moderately advanced severity.

OBJECTIVE

To analyse the diagnostic process from early development onwards and to assess the current state of underpresentation and underdiagnosis of COPD and asthma in primary care in the Netherlands.

METHODS

The population-based study sample consisted of formerly undiagnosed subjects (n = 532) from family practice. Family physicians' (FPs) chronic respiratory disease diagnoses (as recorded over 10 years in their patient records) were compared to a cross-sectional but extensive diagnostic assessment by a chest physician. Logistic regression modelling was used for a retrospective analysis on the relation between respiratory symptoms, practice visit rate and FPs' diagnosis of COPD.

RESULTS

After 10 years, the chest physician diagnosed 26% of subjects as COPD and 16% as (late-onset) asthma. Underpresentation of these patients in family practice was 46%, whereas underdiagnosis occurred in 37% of patients. A chest physician diagnosis of COPD was associated with the presence of chronic cough [odds ratio (OR) = 2.3, 95% confidence interval (CI) 1.1-4.6], a FP diagnosis of COPD with chronic phlegm (OR = 10.6, 95% CI 1.3-83.6). Repeated practice visits (OR = 1.8) and presence of wheeze and breathlessness (OR = 5.5) appeared to trigger the diagnostic process in family practice.

CONCLUSIONS

There is still considerable underpresentation and underdiagnosis of COPD in family practice. As FPs focus on presented symptoms and as detection increases with the frequency of practice visits, diagnostic guidelines should stress the importance of persistent cough and phlegm to support timely diagnosis of COPD in family practice.

Variability of the prevalence of undiagnosed airflow obstruction in smokers using different diagnostic criteria

PURPOSES

To estimate the prevalence of undiagnosed airflow obstruction (AFO) in Hong Kong smokers with no previous diagnosis of respiratory disease, and to assess its variability when applying different prediction equations and diagnostic criteria.

METHODS

A multicenter, population-based, cross-sectional prevalence study was performed in smokers aged 20 to 80 years. Three different criteria (fixed 70% [Global Initiative for Chronic Obstructive Lung Disease and British Thoracic Society], fixed 75%, and European Respiratory Society [ERS]) were applied to define a lower limit of normal (LLN) of the FEV(1)/FVC ratio to compare with the Hong Kong Chinese reference equation (criterion 1), which had used a distribution-free method to obtain the lower fifth percentile of FEV(1)/FVC ratio as the LLN.

RESULTS

In 525 male patients, using criterion 1 (local internal prediction equation) and defining AFO as FEV(1)/FVC less than LLN, the overall prevalence of AFO was 13.7%: 8.3% in age > or = 20 to 40 years, 14.0% in age > or = 40 to 60 years, and 17.8% in age > or = 60 to 80 years. When the local internal prediction equation was used as the comparison reference, the fixed-ratio methods tended to miss AFO in younger age groups and overdiagnose AFO in old age, while the ERS criteria, which uses an almost lower fifth percentile-equivalent method, showed less of such a trend but still only showed moderate agreement with criterion 1.

CONCLUSIONS

Undiagnosed AFO was prevalent in Hong Kong smokers. Estimated prevalence rates were highly affected by the criteria used to define AFO. The predicted lower fifth percentile values calculated from a local reference equation as the LLN of FEV(1)/FVC ratio should be used for the diagnosis of AFO.

Increased risk of depression in COPD patients with higher education and income

This study examined potential modifying effects of income and education on the relationship between chronic obstructive pulmonary disease (COPD) and depression. The analysis was based on 44,963 Canadians aged 35 years or more who participated in the Canadian National Population Health Survey in 1996-1997. Logistic regression analysis was used to examine the association between prevalence of depression and COPD according to sex, income adequacy or educational level. We used a bootstrap procedure to take sampling weights and design effects into account. People with COPD had twice the prevalence of depression compared to those without COPD. The association tended to be stronger in well-educated men [adjusted odds ratio (OR) = 3.02, 95% confidence interval (CI) = 1.04, 8.75] and women (OR = 2.60, 95% CI = 1.55, 4.38) than those less educated (men: OR= 1.19, 95% CI = 0.47, 3.05; women: OR = 1.93, 95% CI = 0.96, 3.87). An increased prevalence of depression associated with COPD was also found in women with higher household income (adjusted odds ratio = 4.57, 95% CI = 2.27, 9.19) than those with lower income. However, this pattern was not found in men. In conclusion, COPD patients with higher education are more likely to be depressed. The modifying effect of income may vary by gender. Possible reasons for these findings are explored.

Airway obstruction in never smokers: results from the Third National Health and Nutrition Examination Survey

PURPOSE

Chronic obstructive pulmonary disease (COPD) is usually described as a disease of cigarette smoking. COPD is rarely considered in persons with no smoking history except in the context of another exposure. Accordingly, the disease has not been well characterized in these "never smokers."

METHODS

We evaluated airway obstruction (defined as forced expiratory volume in 1 second/forced vital capacity <0.70) in US adults aged 30 to 80 years interviewed in the Third National Health and Nutrition Examination Survey with valid spirometry who had never smoked. Previously described risk factors were examined for their association with obstruction in bivariate and multivariate analyses.

RESULTS

Never smokers represented 42% of the Third National Health and Nutrition Examination Survey population aged 30 to 80 years, with obstruction prevalence of 91 per 1000. Never smokers accounted for 4.56 million cases of obstruction, or 23% of the total burden. Among these obstructed never smokers, 19% reported a prior diagnosis of asthma alone, and 12.5% reported COPD (alone or with asthma), leaving 68.5% with no prior respiratory diagnosis. After adjustment for other factors, higher rates of obstruction were significantly associated with increasing age, male sex, lower body mass index, and a history of allergies.

CONCLUSIONS

Never smokers represent a significant proportion of airway obstruction in US adults. Only one fifth of obstruction in this group is explained by asthma. COPD may explain much of the remainder, although known risk factors were not explanatory in this dataset. Recommendations that lung health screening programs be limited to smokers should be reconsidered.

Respiratory symptoms and undiagnosed airflow obstruction in middle-aged adults: the Korean Health and Genome Study

BACKGROUND

The prevalence of undiagnosed airflow obstruction is difficult to measure since it requires screening in population-based samples to identify individuals free of clinical symptoms. The purpose of this report is to examine the prevalence of undiagnosed airflow obstruction and its relation with respiratory symptoms in middle-age adults in the Korean Health and Genome (KHG) Study.

METHODS

The KHG study is an ongoing population-based study of Korean adults aged 40 to 69 years. The current report includes 8,140 men and women without a pulmonary disorder or obstructive lung disease. In this sample, undiagnosed airflow obstruction was defined on the basis of spirometric testing and in the absence of a medical history or a recognized pulmonary disorder. Respiratory symptoms included chronic cough, chronic phlegm, wheezing, and shortness of breath.

RESULTS

Undiagnosed airflow obstruction was observed in 12.4% of the men (470 of 3,806 subjects) and in 3.5% of the women (152 of 4,334 subjects). In men, the age-adjusted prevalence of undiagnosed airflow obstruction increased consistently with increasing number of respiratory symptoms. In those who smoked, there was a 2.3-fold excess in its prevalence when three or more symptoms were present, as compared to when they were absent (27.4% vs 12.0%, p < 0.001). A 2.4-fold excess (20.6% vs 8.5%, p = 0.004) was observed in nonsmoking men, in whom respiratory symptoms were consistently less common than in those who smoked. Respiratory symptoms were unrelated to undiagnosed airflow obstruction in women smokers, although only 3.9% smoked cigarettes. In women who were nonsmokers, the prevalence of undiagnosed airflow obstruction increased from 2.3% in those without a respiratory symptom to 6.0% when three or more symptoms were present (p = 0.003).

CONCLUSIONS

Findings suggest that undiagnosed airflow obstruction is common in Korea with several respiratory symptoms. Whether respiratory symptoms with associations with undiagnosed airflow obstruction can be used to design early intervention strategies that prevent or delay the onset of COPD and its disabling consequences warrants further study.