Hospitalized acute exacerbation in chronic obstructive pulmonary disease - impact on long-term renal outcomes.

INTRODUCTION: Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is a common and preventable event in patients with chronic obstructive pulmonary disease (COPD). Data regarding the impact of AECOPD on short- and long-term renal outcomes are lacking. METHODS: We included all COPD patients who were followed at Queen Mary Hospital (QMH) in year 2015 and reviewed their clinical/renal outcomes in subsequent five years. Relationships between AECOPD and adverse renal outcomes were evaluated. RESULTS: 371 COPD patients were included. 169 patients had hospitalized AECOPD in past one year (HAE group) while 202 patients did not (non-HAE group). 285 patients (76.8%) had renal progression/death and 102 (27.5%) patients developed acute kidney injury (AKI). HAE group showed a more rapid eGFR decline than non-HAE group (-4.64 mL/min/1.73m2/year vs. -2.40 mL/min/1.73m2/year, p = 0.025). HAE group had significantly higher risk for renal progression/death at 5 years [adjusted OR (aOR) 2.380 (95% CI = 1.144-4.954), p = 0.020]. The frequency of hospitalized AECOPD in past 3 years, any AECOPD in past 3 years, hospitalized AECOPD in past 3 years were also predictive of renal progression/death at 5 years [aOR were 1.176 (95% CI = 1.038- 1.331), 2.998 (95% CI = 1.438-6.250) and 2.887 (95% CI = 1.409-5.917) respectively; p = 0.011, 0.003 and 0.004]. HAE group also showed significantly higher risk of AKI [adjusted HR (aHR) 2.430; 95% CI = 1.306-4.519, p = 0.005]. CONCLUSIONS: AECOPD, in particular HAE, was associated with increased risk of renal progression/death and AKI. Prevention of AECOPD, especially HAE, may potentially improve short- and long-term renal outcomes in COPD patients.

Cardiovascular outcomes in obstructive sleep apnoea and implications of clinical phenotyping on effect of CPAP treatment.

BACKGROUND: There is a growing awareness of the heterogeneity of obstructive sleep apnoea (OSA). Clinical trials of CPAP treatment on cardiovascular protection have been mostly negative. We aimed to assess the association between polysomnographic parameters and incident major adverse cardiovascular events (MACEs), and to investigate if the CPAP effect could be better delineated among clinical subgroups. METHODS: This sleep cohort study was conducted using a clinical database and territory-wide electronic health administration data in Hong Kong. Cox regressions were used to calculate HRs. Latent class analysis was used to cluster patients with OSA according to clinical and polysomnographic features. RESULTS: Of 1860 eligible Chinese subjects who underwent polysomnography (2006-2013), 1544 (83%) had OSA. Over median follow-up of 8.3 years, 278 (14.9%) experienced MACEs. Apnoea-hypopnoea index (AHI) did not predict MACEs (HR: 0.95; 95% CI 0.76 to 1.17), whereas sleep time with oxygen saturation <90% (TST90) (HR: 1.41; 95% CI 1.10 to 1.81) was an independent predictor of MACEs, as were wake and nocturnal heart rate. In moderate-severe OSA (n=1108) who were indicated for CPAP treatment, regular CPAP was not associated with reduction of incident MACEs. Further cluster analysis identified a subgroup (n=333) who was younger, more obese, had more severe OSA (higher AHI and TST90) and more cardiovascular risks, in whom regular CPAP was associated with a lower risk of MACEs (HR:0.49, 95% CI 0.25 to 0.95). CONCLUSIONS: OSA-related TST90 and mean heart rate, but not AHI, were robust predictors of MACEs. A clinical phenotype subgroup who demonstrated beneficial effect of CPAP treatment was identified.

USPSTF2013 versus PLCOm2012 lung cancer screening eligibility criteria (International Lung Screening Trial): interim analysis of a prospective cohort study.

BACKGROUND: Lung cancer is a major health problem. CT lung screening can reduce lung cancer mortality through early diagnosis by at least 20%. Screening high-risk individuals is most effective. Retrospective analyses suggest that identifying individuals for screening by accurate prediction models is more efficient than using categorical age-smoking criteria, such as the US Preventive Services Task Force (USPSTF) criteria. This study prospectively compared the effectiveness of the USPSTF2013 and PLCOm2012 model eligibility criteria. METHODS: In this prospective cohort study, participants from the International Lung Screening Trial (ILST), aged 55-80 years, who were current or former smokers (ie, had ≥30 pack-years smoking history or ≤15 quit-years since last permanently quitting), and who met USPSTF2013 criteria or a PLCOm2012 risk threshold of at least 1·51% within 6 years of screening, were recruited from nine screening sites in Canada, Australia, Hong Kong, and the UK. After enrolment, patients were assessed with the USPSTF2013 criteria and the PLCOm2012 risk model with a threshold of at least 1·70% at 6 years. Data were collected locally and centralised. Main outcomes were the comparison of lung cancer detection rates and cumulative life expectancies in patients with lung cancer between USPSTF2013 criteria and the PLCOm2012 model. In this Article, we present data from an interim analysis. To estimate the incidence of lung cancers in individuals who were USPSTF2013-negative and had PLCOm2012 of less than 1·51% at 6 years, ever-smokers in the Prostate Lung Colorectal and Ovarian Cancer Screening Trial (PLCO) who met these criteria and their lung cancer incidence were applied to the ILST sample size for the mean follow-up occurring in the ILST. This trial is registered at ClinicalTrials.gov, NCT02871856. Study enrolment is almost complete. FINDINGS: Between June 17, 2015, and Dec 29, 2020, 5819 participants from the International Lung Screening Trial (ILST) were enrolled on the basis of meeting USPSTF2013 criteria or the PLCOm2012 risk threshold of at least 1·51% at 6 years. The same number of individuals was selected for the PLCOm2012 model as for the USPSTF2013 criteria (4540 [78%] of 5819). After a mean follow-up of 2·3 years (SD 1·0), 135 lung cancers occurred in 4540 USPSTF2013-positive participants and 162 in 4540 participants included in the PLCOm2012 of at least 1·70% at 6 years group (cancer sensitivity difference 15·8%, 95% CI 10·7-22·1%; absolute odds ratio 4·00, 95% CI 1·89-9·44; p<0·0001). Compared to USPSTF2013-positive individuals, PLCOm2012-selected participants were older (mean age 65·7 years [SD 5·9] vs 63·3 years [5·7]; p<0·0001), had more comorbidities (median 2 [IQR 1-3] vs 1 [1-2]; p<0·0001), and shorter life expectancy (13·9 years [95% CI 12·8-14·9] vs 14·8 [13·6-16·0] years). Model-based difference in cumulative life expectancies for those diagnosed with lung cancer were higher in those who had PLCOm2012 risk of at least 1·70% at 6 years than individuals who were USPSTF2013-positive (2248·6 years [95% CI 2089·6-2425·9] vs 2000·7 years [1841·2-2160·3]; difference 247·9 years, p=0·015). INTERPRETATION: PLCOm2012 appears to be more efficient than the USPSTF2013 criteria for selecting individuals to enrol into lung cancer screening programmes and should be used for identifying high-risk individuals who benefit from the inclusion in these programmes. FUNDING: Terry Fox Research Institute, The UBC-VGH Hospital Foundation and the BC Cancer Foundation, the Alberta Cancer Foundation, the Australian National Health and Medical Research Council, Cancer Research UK and a consortium of funders, and the Roy Castle Lung Cancer Foundation for the UK Lung Screen Uptake Trial.

Implementation of evidence on management of pleural diseases: insights from a territory-wide survey of clinicians in Hong Kong.

BACKGROUND: Major advances in management of common pleural diseases have taken place in the past decade. However, pleural diseases are often managed by physicians of diverse training background and research on implementation of new knowledge is scanty. We aim to evaluate the practice pattern in pleural medicine among physicians in Hong Kong, for identification of possible gaps for clinical service improvement. METHODS: The Hong Kong Thoracic Society undertook a cross-sectional questionnaire survey in 2019, targeting clinicians of various subspecialties in internal medicine and levels of experience (basic and higher trainees, specialists) from twelve regional hospitals of diverse service scopes throughout Hong Kong. Respondents were selected by non-probability quota sampling. The questionnaire tool consisted of 46 questions covering diagnostic and therapeutic aspects of common pleural diseases. The responses were anonymous, and analysed independently using SPSS statistics software. RESULTS: The survey collected 129 responses, 47(36%) were from clinicians specialized in respiratory medicine. Majority of the respondents (98%) managed pleural diseases, including performing pleural procedures in their practice. Fifty-five percent of all the respondents had not received any formal training in transthoracic ultrasonography. A significant proportion of clinicians were unaware of pleuroscopy for investigation of exudative pleural effusion, indwelling pleural catheter for recurrent malignant pleural effusion, and combined intra-pleural Alteplase plus DNase for treatment of pleural infection (30%, 15% and 70% of non-respiratory clinicians respectively). Significant heterogeneity was found in the management of pleural infection, malignant pleural effusion and pneumothorax among respiratory versus non-respiratory clinicians. Contributing factors to the observed heterogeneity included lack of awareness or training, limited accessibility of drugs, devices, or dedicated service support. CONCLUSION: Significant heterogeneity in management of pleural diseases was observed among medical clinicians in Hong Kong. Continuous medical education and training provision for both specialists and non-specialists has to be strengthened to enhance the implementation of advances, improve quality and equity of healthcare provision in pleural medicine.

Circulating adipocyte fatty acid-binding protein is reduced by continuous positive airway pressure treatment for obstructive sleep apnea-a randomized controlled study.

PURPOSE: The circulating level of adipocyte fatty acid-binding protein (AFABP), a biomarker with prognostic and therapeutic importance in metabolic disorders, has been shown to be elevated in obstructive sleep apnea (OSA). This randomized controlled study aimed to investigate the effect of continuous positive airway pressure (CPAP) treatment for OSA on AFABP levels. METHODS: Consecutive subjects attending sleep study were invited if they were confirmed to have severe OSA and were free of metabolic diseases. Participants were randomized (1:1) into CPAP or observation group for 4 weeks. Demographics, anthropometric data, and circulating biomarkers were checked at baseline and after the 4-week study period. RESULTS: Ninety subjects were randomized. The mean age was 46 ± 9 years old; 82% were male. Their mean body mass index (BMI) was 29 ± 5 kg/m2. By intention-to-treat approach, the CPAP group showed significant reductions in Epworth sleepiness scale and morning systolic blood pressure (- 7.2 mmHg, - 12.7 to - 1.7 mmHg, p = 0.011), but no significant difference in AFABP, adiponectin, C-reactive protein (CRP), and 8-isoprostane levels. In the per-protocol analysis, when only those who were compliant to CPAP were included, a significant reduction in AFABP (- 7.32 ng/ml, - 13.58, - 1.06, p = 0.023) were found in the CPAP-treated group compared with the control group, along with improvements in clinical parameters. Changes in AFABP were independently associated with both systolic blood pressure (ß = 0.289, p = 0.028) and diastolic blood pressure (ß = 0.217, p = 0.030). CONCLUSION: CPAP therapy used regularly over 4 weeks for severe OSA lowered circulating AFABP level, suggesting a potential beneficial effect of OSA treatment on alleviating metabolic risks. TRIAL REGISTRATION: The research protocol was registered at the National Institutes of Health clinical trials registry (NCT01173432).

Rapid versus gradual lung function decline in bronchiolitis obliterans syndrome after haematopoietic stem cell transplantation is associated with survival outcome.

BACKGROUND AND OBJECTIVE: Bronchiolitis obliterans syndrome (BOS) after haematopoietic stem cell transplantation (HSCT) presents with lung function decline. The pattern of lung function decline after BOS diagnosis could impact prognostication of BOS as a complication after HSCT. The aim of this study was to assess the impact of lung function decline on overall survival (OS) in BOS subjects. METHODS: Subjects with BOS were compared to those without BOS and matched for age, gender, primary diagnoses, conditioning regimes and chronic graft versus host disease. Lung function tests at baseline, at BOS diagnosis and every 3 months after HSCT were evaluated. RESULTS: Of the 1461 subjects undergoing allogeneic HSCT (allo-HSCT) between 1998 and 2015, 95 (6.5%) were diagnosed with BOS. A total of 159 matched HSCT recipients without BOS were identified. A 25% decline in FEV1 within the first 3 months after BOS diagnosis would separate BOS subjects into a subgroup with initial rapid decline and another subgroup with initial gradual decline in lung function. The rapid decline group showed lower subsequent lung function parameters and significantly worse OS compared to the gradual decline group (P = 0.013). CONCLUSION: Post-HSCT BOS subjects with initial rapid lung function decline within 3 months after BOS diagnosis will have significantly poorer lung function and worse OS compared to those with initial gradual decline in lung function after BOS diagnosis. HSCT BOS patients with rapid initial decline in lung function warrant closer monitoring for the development of other post-HSCT complications that could affect their survival.

Effect of an Indwelling Pleural Catheter vs Talc Pleurodesis on Hospitalization Days in Patients With Malignant Pleural Effusion: The AMPLE Randomized Clinical Trial.

Importance: Indwelling pleural catheter and talc pleurodesis are established treatments for malignant pleural effusions among patients with poor prognosis. Objective: To determine whether indwelling pleural catheters are more effective than talc pleurodesis in reducing total hospitalization days in the remaining lifespan of patients with malignant pleural effusion. Design, Setting, and Participants: This open-label, randomized clinical trial included participants recruited from 9 centers in Australia, New Zealand, Singapore, and Hong Kong between July 2012 and October 2014; they were followed up for 12 months (study end date: October 16, 2015). Patients (n = 146) with symptomatic malignant pleural effusion who had not undergone indwelling pleural catheter or pleurodesis treatment were included. Interventions: Participants were randomized (1:1) to indwelling pleural catheter (n = 74) or talc pleurodesis (n = 72), minimized by malignancy (mesothelioma vs others) and trapped lung (vs not), and stratified by region (Australia vs Asia). Main Outcomes and Measures: The primary end point was the total number of days spent in hospital from procedure to death or to 12 months. Secondary outcomes included further pleural interventions, patient-reported breathlessness, quality-of-life measures, and adverse events. Results: Among the 146 patients who were randomized (median age, 70.5 years; 56.2% male), 2 withdrew before receiving the randomized intervention and were excluded. The indwelling pleural catheter group spent significantly fewer days in hospital than the pleurodesis group (median, 10.0 [interquartile range [IQR], 3-17] vs 12.0 [IQR, 7-21] days; P = .03; Hodges-Lehmann estimate of difference, 2.92 days; 95% CI, 0.43-5.84). The reduction was mainly in effusion-related hospitalization days (median, 1.0 [IQR, 1-3] day with the indwelling pleural catheter vs 4.0 (IQR, 3-6) days with pleurodesis; P < .001; Hodges-Lehmann estimate, 2.06 days; 95% CI, 1.53-2.58). Fewer patients randomized to indwelling pleural catheter required further ipsilateral invasive pleural drainages (4.1% vs 22.5%; difference, 18.4%; 95% CI, 7.7%-29.2%). There were no significant differences in improvements in breathlessness or quality of life offered by indwelling pleural catheter or talc pleurodesis. Adverse events were seen in 22 patients in the indwelling pleural catheter group (30 events) and 13 patients in the pleurodesis group (18 events). Conclusions and Relevance: Among patients with malignant pleural effusion, treatment with an indwelling pleural catheter vs talc pleurodesis resulted in fewer hospitalization days from treatment to death, but the magnitude of the difference is of uncertain clinical importance. These findings may help inform patient choice of management for pleural effusion. Trial Registration: anzctr.org.au Identifier: ACTRN12611000567921.

Obstructive sleep apnoea, insulin resistance and adipocytokines.

Obstructive sleep apnoea (OSA) is associated with multiple cardiometabolic abnormalities. Obesity is considered a major risk factor for the development of OSA, and it is also an established risk factor for insulin resistance and other cardiometabolic disorders. The enigma remains whether OSA has any causal role in the adverse metabolic profile, independent of or beyond that due to obesity. Sleep apnoeas and hypopnoeas result directly in intermittent hypoxaemia and cerebral arousals, both of which may evoke a cascade of downstream biologic responses in various body tissues and cells. Adipose tissue is a major source of adipocytokines many of which play important roles in the regulation of various metabolic functions. It is hypothesized that OSA may, through its unique pathophysiology, affect metabolic function through modulation of production or action of adipocytokines. This review focuses on insulin resistance, glucose metabolism and relevant adipocytokines in the context of OSA.

Electronic cigarettes. A position statement of the forum of international respiratory societies.

BACKGROUND: Awareness and usage of electronic cigarettes has exponentially increased during the last few years, especially among young people and women in some countries. The rapid acceptance of electronic cigarettes may be attributed in part to the perception created by marketing and the popular press that they are safer than combustible cigarettes. GOALS: To alert and advise policy makers about electronic cigarettes and their potential hazards. METHODS: Using The Union's position paper on electronic cigarettes as the starting template, the document was written using an iterative process. Portions of the manuscript have been taken directly from the position papers of participating societies. RESULTS: Because electronic cigarettes generate less tar and carcinogens than combustible cigarettes, use of electronic cigarettes may reduce disease caused by those components. However, the health risks of electronic cigarettes have not been adequately studied. Studies looking at whether electronic cigarettes can aid smoking cessation have had inconsistent results. Moreover, the availability of electronic cigarettes may have an overall adverse health impact by increasing initiation and reducing cessation of combustible nicotine delivery products. CONCLUSIONS: The health and safety claims regarding electronic nicotine delivery devices should be subject to evidentiary review. The potential benefits of electronic cigarettes to an individual smoker should be weighed against potential harm to the population of increased social acceptability of smoking and use of nicotine, the latter of which has addictive power and untoward effects. As a precaution, electronic nicotine delivery devices should be restricted or banned until more information about their safety is available. If they are allowed, they should be closely regulated as medicines or tobacco products.

Clinical testing for molecular targets for personalized treatment in lung cancer.

Lung cancer is the leading cause of cancer mortality worldwide. Over the past decades, the management of advanced stage lung cancer has been revolutionized from very limited options of systemic chemotherapy with limited efficacy to the present stage of testing for biomarkers (epidermal growth factor receptor (EGFR), gene mutations) to guide therapeutic decision and to improve efficacy of treatment. Relevant advancement in understanding of lung cancer biology also revealed that different lung tumours may carry different cancer driver gene mutations and thus adopt different carcinogenic pathways. These cancer driver gene mutations were found to be mutually exclusive in individual lung tumour further supporting the rationale of testing tumour sample for the presence of these mutations, especially when there could be corresponding specific agents against these molecular targets. The aim of this article is to review the current understanding of molecular targets that are important in the personalized therapy of lung cancer and how the testing for these molecular targets, namely EGFR, KRAS and ALK, will guide therapeutic decision in advanced stage lung cancer.

Endobronchial ultrasound-guided transbronchial needle aspiration in lung cancer: the first experience in Hong Kong.

OBJECTIVE: To investigate the diagnostic performance and safety of endobronchial ultrasound-guided transbronchial needle aspiration in patients presenting with radiological features of lung cancer. DESIGN: Prospective case series. SETTING: University teaching hospital, Hong Kong. PATIENTS: Consecutive patients with mediastinal or hilar abnormalities suspected of or confirmed as having lung cancer underwent endobronchial ultrasound-guided transbronchial needle aspiration and presented between August 2006 and December 2010. MAIN OUTCOME MEASURES: Diagnostic performance (including sensitivity, specificity, negative predictive value and accuracy), procedural complications, and tissue adequacy for molecular profiling. RESULTS: A total of 269 procedures were performed in 259 patients, with malignancy confirmed in 210 (81%) of them. In the whole cohort with confirmed or suspected lung cancer, the overall sensitivity, specificity, negative predictive value, and accuracy of endobronchial ultrasound-guided transbronchial needle aspiration were 87%, 100%, 74%, and 91%, respectively. Among 42 patients with tumour samples sent for mutation tests (epidermal growth factor receptor and/or anaplastic lymphoma kinase), 40 (95%) were found to be adequate. No complication or mortality ensued from these procedures. CONCLUSION: Endobronchial ultrasound-guided transbronchial needle aspiration is highly effective in determining the diagnosis and lymph node staging in patients with lung cancer. In combination with its excellent safety profile, it should be considered a frontline diagnostic test for patients presenting with mediastinal abnormalities suspicious of lung cancer.

Air Pollution and Lung Cancer: A Review by International Association for the Study of Lung Cancer Early Detection and Screening Committee.

INTRODUCTION: The second leading cause of lung cancer is air pollution. Air pollution and smoking are synergistic. Air pollution can worsen lung cancer survival. METHODS: The Early Detection and Screening Committee of the International Association for the Study of Lung Cancer formed a working group to better understand issues in air pollution and lung cancer. These included identification of air pollutants, their measurement, and proposed mechanisms of carcinogenesis. The burden of disease and the underlying epidemiologic evidence linking air pollution to lung cancer in individuals who never and ever smoked were summarized to quantify the problem, assess risk prediction models, and develop recommended actions. RESULTS: The number of estimated attributable lung cancer deaths has increased by nearly 30% since 2007 as smoking has decreased and air pollution has increased. In 2013, the International Agency for Research on Cancer classified outdoor air pollution and particulate matter with aerodynamic diameter less than 2.5 microns in outdoor air pollution as carcinogenic to humans (International Agency for Research on Cancer group 1) and as a cause of lung cancer. Lung cancer risk models reviewed do not include air pollution. Estimation of cumulative exposure to air pollution exposure is complex which poses major challenges with accurately collecting long-term exposure to ambient air pollution for incorporation into risk prediction models in clinical practice. CONCLUSIONS: Worldwide air pollution levels vary widely, and the exposed populations also differ. Advocacy to lower sources of exposure is important. Health care can lower its environmental footprint, becoming more sustainable and resilient. The International Association for the Study of Lung Cancer community can engage broadly on this topic.

Association of Sodium-Glucose Cotransporter 2 Inhibitor vs Dipeptidyl Peptidase-4 Inhibitor Use With Risk of Incident Obstructive Airway Disease and Exacerbation Events Among Patients With Type 2 Diabetes in Hong Kong.

Importance: Patients with diabetes are at higher risk for obstructive airway disease (OAD). In recent meta-analyses of post hoc analyses of cardiorenal trials, sodium-glucose cotransporter 2 inhibitors (SGLT2Is) were suggested to reduce the risk of OAD adverse events. However, a clinical investigation of this association is warranted. Objective: This study aimed to investigate the association of SGLT2I use vs dipeptidyl peptidase-4 inhibitor (DPP4I) use with OAD incidence and exacerbation events in patients with type 2 diabetes. Design, Setting, and Participants: This retrospective population-based cohort study used electronic health data from a territory-wide electronic medical database in Hong Kong. Data were collected for patients with type 2 diabetes who were prescribed SGLT2Is or DPP4Is between January 1, 2015, and December 31, 2018. Patients were followed for a median of 2.2 years between January 1, 2015, and December 31, 2020. A prevalent new-user design was adopted to match patients based on previous exposure to the study drugs. Propensity score matching was used to balance baseline characteristics. Exposures: Patients with type 2 diabetes using SGLT2Is (exposure of interest) or DPP4Is (active comparator). Main Outcomes and Measures: The main outcomes were the first incidence of OAD and the count of OAD exacerbations. The risk of incident OAD was estimated using a Cox proportional hazards regression model. The rate of exacerbations was estimated using zero-inflated Poisson regression. Statistical analysis was performed on November 13, 2022. Results: This study included 30 385 patients. The propensity score-matched non-OAD cohort (incidence analysis) consisted of 5696 SGLT2I users and 22 784 DPP4I users, while the matched OAD cohort (exacerbations analysis) comprised 381 SGLT2I users and 1524 DPP4I users. At baseline, 56% of patients in the non-OAD cohort were men and the mean (SD) age was 61.2 (9.9) years; 51% of patients in the OAD cohort were men and the mean age was 62.2 (10.8) years. Compared with DPP4I use, SGLT2I use was associated with a lower risk of incident OAD (hazard ratio, 0.65 [95% CI, 0.54-0.79]; P < .001) and a lower rate of exacerbations (rate ratio, 0.54 [95% CI, 0.36-0.83]; P = .01). The associations were consistent in sex subgroup analysis. Conclusions and Relevance: The findings of this retrospective cohort study of patients with type 2 diabetes in Hong Kong suggest that SGLT2I use was associated with a reduced risk of incident OAD and a lower rate of exacerbations in a clinical setting compared with DPP4I use. These findings further suggest that SGLT2Is may provide additional protective effects against OAD for patients with type 2 diabetes and that further investigation is warranted.

Issues in pulmonary function testing for the screening and diagnosis of chronic obstructive pulmonary disease.

PURPOSE OF REVIEW: The purpose of this review article is to provide an up-to-date summary on the current evidence for or against the use of lung function tests as screening and diagnostic tools for airflow obstruction in chronic obstructive pulmonary disease (COPD), and to consider the relevant issues in context. RECENT FINDINGS: COPD is characterized by chronic respiratory symptoms and airflow limitation with only partial reversibility on lung function testing. However, screening on a population basis or of an enriched 'at-risk' subset like chronic smokers is not supported by findings from previous epidemiological studies, screening trials or in currently published clinical management guidelines by professional societies and review bodies. The definition of airflow obstruction and the classification of disease severity of COPD also differ slightly between guidelines and statements from different professional societies. SUMMARY: Given the experience from previous screening trials and controversial classification of airflow obstruction by severity, it is impossible to have accurate screening results for COPD based on lung function tests alone. Clinical respiratory symptoms should be taken into consideration in terms of the diagnosis and management of COPD, as well as in any screening trial or programme that is to be attempted or implemented.

Clinical applications of lung function tests: a revisit.

The development and clinical application of lung function tests have a long history, and the various components of lung function tests provide very important tools for the clinical evaluation of respiratory health and disease. Spirometry, measurement of the diffusion factor, bronchial provocation tests and forced oscillation techniques have found diverse clinical applications in the diagnosis and monitoring of respiratory diseases, such as chronic obstructive pulmonary disease, interstitial lung diseases and asthma. However, there are some practical issues to be resolved, including the establishment of reference values for individual test parameters and the roles of these tests in preoperative risk assessment and pulmonary rehabilitation. Novel measurements, including negative expiratory pressure, the fraction of exhaled nitric oxide and analysis of exhaled breath condensate, may provide new insights into physiological abnormalities or airway inflammation in respiratory diseases, but their clinical applications need to be further evaluated. The clinical application of lung function tests continues to face challenges, which may be overcome by further improvement of conventional techniques for lung function testing and further specification of new testing techniques.