Chronic obstructive pulmonary disease in non-smokers: a case-comparison study

Clinical characteristics of chronic obstructive pulmonary disease in never-smokers: A systematic review

INTRODUCTION

Chronic Obstructive Pulmonary Disease (COPD) is the third cause of death worldwide. While tobacco smoking is a key risk factor, COPD also occurs in never-smokers (NS). However, available evidence on risk factors, clinical characteristics, and natural history of the disease in NS is scarce. Here, we perform a systematic review of the literature to better describe the characteristics of COPD in NS.

METHODS

We searched different databases following the PRISMA guidelines with explicit inclusion and exclusion criteria. A purpose-designed quality scale was applied to the studies included in the analysis. It was not possible to pool the results due to the high heterogeneity of the studies included.

RESULTS

A total of 17 studies that met the selection criteria were included, albeit only 2 of them studied NS exclusively. The total number of participants in these studies were 57,146 subjects,25,047 of whom were NS and 2655 of the latter had NS-COPD. Compared to COPD in smokers, COPD in NS is more frequent in women and older ages, and is associated with a slightly higher prevalence of comorbidities. There are not enough studies to understand if COPD progression and clinical symptoms in NS are different to that of ever-smokers.

CONCLUSIONS

There is a significant knowledge gap on COPD in NS. Given that COPD in NS account for about a third of all COPD patients in the world, particularly in low-middle income countries, and the decrease in tobacco consumption in high income countries, understanding COPD in NS constitutes a public-health priority.

Chronic obstructive pulmonary disease in never-smokers: risk factors, pathogenesis, and implications for prevention and treatment

Chronic obstructive pulmonary disease (COPD) was traditionally thought to be caused by tobacco smoking. However, recognition of the importance of non-smoking-related risk factors for COPD has increased over the past decade, with evidence on the burden, risk factors, and clinical presentations of COPD in never-smokers. About half of all COPD cases worldwide are due to non-tobacco-related risk factors, which vary by geographical region. These factors include air pollution, occupational exposures, poorly controlled asthma, environmental tobacco smoke, infectious diseases, and low socioeconomic status. Impaired lung growth during childhood, caused by a range of early-life exposures, is associated with an increased risk of COPD. Potential mechanisms for the pathogenesis of COPD in never-smokers include inflammation, oxidative stress, airway remodelling, and accelerated lung ageing. Compared with smokers who develop COPD, never-smokers with COPD have relatively mild chronic respiratory symptoms, little or no emphysema, milder airflow limitation, and fewer comorbidities; however, exacerbations can still be frequent. Further research-including epidemiological, translational, clinical, and implementation studies-is needed to address gaps in understanding and to advance potential solutions to reduce the burden of COPD in never-smokers.

Fixed-dose combination of three drugs, i.e. LABA/LAMA/ICS for COPD: Results of a real-world study from India

BACKGROUND

The use of triple therapy with inhaled corticosteroids, long-acting beta-agonist and long-acting antimuscarinics has been shown to be beneficial in COPD patients who continue to have symptoms and exacerbations, despite receiving dual bronchodilator combinations. This study assessed the real-world effectiveness and safety of once-daily, fixed-dose combination of Tiotropium/Formoterol/Ciclesonide (TFC) (18 mcg/12 mcg/400 mcg) via dry powder inhaler (DPI) or metered dose inhaler (MDI) in patients with COPD.

PATIENTS AND METHODS

In this 24-week, open-label, prospective, non-comparative, multicentre, real-world study, COPD patients requiring triple therapy as judged by their physician, were enrolled. The primary endpoint was mean change from baseline in pre-dose Forced Expiratory Volume in 1 s (FEV₁) at week 24. Pre and post-dose (30 min) FEV₁, Forced Vital capacity (FVC), COPD Assessment Test (CAT), modified Medical Research Council (mMRC) score and safety were also evaluated. A post-hoc analysis was conducted to evaluate the efficacy of the triple drug combination among smoker and non-smoker COPD patients.

RESULTS

Out of the 297 patients enrolled [mean age 61 ± 10 years; 84.8% males; 55.2% smokers and post-dose FEV₁ (% predicted) 39 ± 16%], 253 completed the study. Mean change in pre-dose FEV₁ from baseline to week 24 increased significantly after administering the triple drug combination [580 ± 600 mL, 95% CI (510, 650 mL), p < 0.0001]. The increase in the pre-dose FEV₁ was significant at all time points (p < 0.0001). Similar improvements were seen in pre-dose FVC, post-dose FEV₁ and post-dose FVC across all time points. CAT scores and the proportion of patients with improved mMRC score improved at all visits. The post-hoc analysis showed that TFC significantly increased pre-dose FEV₁ both among smokers [mean change 200 ± 430 mL, 95% CI (130, 270 mL), p < 0.0001] as well as non-smokers [990 ± 470 mL, 95% CI (900, 1070 mL), p < 0.0001] at week 24. This difference was significant from week 12 onwards. Mean change in pre and post-dose FEV₁ and FVC was significant across all visits between the two groups. At week 24, CAT score reduced significantly from baseline (overall: -6.6 ± 6.07; smokers: -5.17 + 6.96; non-smokers: 8.06 ± 4.44; all p < 0.0001). The mean difference between the two groups was 2.88 (p < 0.0001) at week 24. TFC was well tolerated.

CONCLUSION

In this real world, multicentre study in India, TFC significantly improved lung function, symptoms and quality of life among all patients with COPD, but the effect was more pronounced among non-smoker COPD patients.

Prevalence, risk factors and clinical correlates of COPD in a rural setting in Tanzania

Chronic obstructive pulmonary disease (COPD) causes substantial burden of disease in developed countries, but there are limited data from Africa. We aimed to estimate the prevalence of COPD in Tanzania and identify the risk factors associated with it.This was a cross-sectional descriptive survey involving adults aged ≥35 years. We collected data on symptoms and risk factors using the Burden of Obstructive Lung Diseases questionnaire. Spirometry was performed and COPD diagnosed based on post-bronchodilator forced expiratory volume in 1 s/forced vital capacity <70%. We also measured indoor and outdoor carbon monoxide (CO) levels.A total of 869 participants (49.1% females) completed the questionnaires. Of these, 57.1% completed post-bronchodilator spirometry. Of the 25.2% ever-smokers, only 5.4% were current smokers. COPD prevalence was estimated at 17.5% (21.7% in males and 12.9% in females). COPD was associated with a history of cough, phlegm production and wheezing. 51.7% of COPD patients reported cough and 85% had mild to moderate airway limitation. Females had a higher rate of exacerbation. Pulmonary tuberculosis (TB) was reported in 10% of patients. Only 1.7% of patients who were diagnosed as COPD had ever received any medication, with only one female COPD patient having received an inhaler. 99.5% of the population used biomass fuels for cooking. The majority of households had CO levels up to 20 ppm.The prevalence of COPD in Tanzania is high, with a peak at a relatively young age and a preponderance in males. A history of TB, cigarette smoking and male sex are important risk factors. Indoor air pollution coupled with use of biomass fuel for cooking and heating may be an important risk factor for developing COPD in rural Tanzania. However, these factors need to be studied further.

Neutrophil CD64 as a Marker of Bacterial Infection in Acute Exacerbations of Chronic Obstructive Pulmonary Disease

Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are responsible for most mortality in patients with chronic obstructive pulmonary disease (COPD) and are caused mainly by bacterial infection. We analyzed and compared neutrophil CD64 expression (using the ratio of CD64 level in neutrophils to that in lymphocytes as an index), serum C-reactive protein (CRP), procalcitonin (PCT) levels, white blood cell (WBC) count, and neutrophil percentage among healthy subjects and patients with stable COPD or AECOPD. Compared with patients with COPD and healthy subjects, patients with AECOPD demonstrated significantly increased CD64 index, CRP, PCT, WBC count, and neutrophil percentage. Interestingly, CD64 index and PCT were both significantly higher in patients with AECOPD with positive bacterial sputum culture than those with negative culture. Furthermore, CD64 index and PCT were positively correlated in AECOPD, and there was also correlation between CD64 index and CRP, WBC, and neutrophil percentage. These data suggest that CD64 index is a relevant marker of bacterial infection in AECOPD. We divided patients with AECOPD into CD64-guided group and conventional treatment group. In CD64-guided group, clinicians prescribed antibiotics based on CD64 index; while in the conventional treatment group, clinicians relied on experience and clinical symptoms to determine the necessity for antibiotics. We found that the efficacy of antibiotic treatment in CD64-guided group was significantly improved compared with the conventional treatment group, including reduction of hospital stays and cost and shortened antibiotic treatment duration. Thus, the CD64 index has important diagnostic and therapeutic implications for antibiotic treatment of patients with AECOPD.

Asthma COPD Overlap Syndrome on CT Densitometry: A Distinct Phenotype from COPD

Patients with asthma COPD overlap syndrome (ACOS) are an important but poorly characterized group. This study sought to explore the distinct characteristics of ACOS on CT densitometry. The study population was randomly selected from communities via questionnaires. All participants underwent low-dose volumetric chest CT both before and after bronchodilator administration. Each CT scan was performed at full-inspiration and full-expiration for CT densitometry. Emphysema index (EI), air trapping (AT), mean lung density (MLD) and total lung volume (TLV) were measured and compared between the ACOS and COPD groups. The distributions of both EI and AT were compared between patients with ACOS and COPD. The variations between the pre- and post-BD measurements observed in patients with ACOS were compared with those in patients with COPD. A total of 71 patients completed the study, including 32 patients with COPD and 39 patients with ACOS. The patients with ACOS exhibited lower EI and more upper-zone-predominant EI distributions, compared with the patients with COPD. No significant differences were exhibited in AT and its distribution. Following bronchodilator administration, the variations in AT and expiratory MLD were greater in patients with ACOS than in patients with COPD. No differences were observed in the variations of EI and inspiratory MLD. Our results indicate that patients with ACOS have lower extent of emphysema and different emphysema distribution, as well as greater post-BD variations in air trapping, compared with patients with COPD. These findings suggest that CT densitometry characterizes ACOS as a distinct phenotype from COPD.

Epidemiology of chronic obstructive pulmonary disease: a population-based study in Krasnoyarsk region, Russia

BACKGROUND

Krasnoyarsk region is a territory with the widespread risk factors for chronic obstructive pulmonary disease (COPD) such as tobacco smoke, air pollution, and occupational exposure. An assessment of COPD prevalence based on medical diagnosis statistics underestimates the true COPD prevalence. This study aims to evaluate how medical examinations may increase the accuracy of estimates of COPD prevalence.

METHODS

True COPD prevalence was estimated as a number of patients with the established disease diagnosis supplemented by the additional disease cases detected during medical examinations per 1,000 inhabitants of the region. Official medical statistics data and the data collected from the Global Alliance against Chronic Respiratory Diseases program 2011 among 15,000 inhabitants of the region aged 18 years and older were analyzed.

RESULTS

This study revealed the COPD cases without official medical diagnosis. The true prevalence of COPD is estimated to be two times higher than the prevalence estimates based on medical diagnosis statistics.

CONCLUSION

Undiagnosed and untreated cases of COPD result in severe COPD forms as well as addition of severe comorbidities. Because of this, there is an increase in the index of potential years of life lost. Conducting special medical examinations may increase the number of COPD cases detected at the early stages of the disease. This, in turn, may reduce the overall burden of the disease for the population of the region.

Risk factors for chronic obstructive pulmonary disease among never-smokers in Korea

Background

Chronic obstructive pulmonary disease (COPD) patients include those who have never smoked. However, risk factors other than smoking in never-smokers have not been elucidated sufficiently. This study investigated the risk factors for COPD among never-smokers in Korea using population-based data.

Methods

The data were retrieved from the Korean National Health and Nutrition Survey IV conducted from 2007 to 2009. Among subjects aged 40 years or older who underwent appropriate pulmonary function tests, never-smokers not diagnosed with asthma and not showing a restrictive pattern on pulmonary function tests were enrolled. Risk factors of COPD in never-smokers were analyzed using logistic regression models.

Results

Among 24,871 participants in the representative Korean cohort, 3,473 never-smokers were enrolled. COPD patients accounted for 7.6% of the never-smokers. In the logistic regression analysis, low education status (odds ratio [OR]: 2.0; 95% confidence interval [CI]: 1.2–3.2), occupational exposure (OR: 2.6; 95% CI: 1.3–5.3), a history of tuberculosis (OR: 4.5; 95% CI: 2.3–8.7), bronchiectasis (OR: 6.0; 95% CI: 1.4–25.4), male sex (OR: 4.2; 95% CI: 2.6–6.7), advanced age (60–69 years vs 40–49 years; OR: 3.8; 95% CI: 2.0–7.0), and being underweight (body mass index <18.5 vs 18.0–24.9 kg/m²; OR: 3.1; 95% CI: 1.0–9.4) were associated with the development of COPD.

Conclusion

Low education status, manual labor, a history of tuberculosis and bronchiectasis, as well as male sex, advanced age and being underweight were risk factors for COPD in Korean never-smokers.