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Abstract Purpose The present study aimed to investigate the clinical characteristics and lung function impairment in young people diagnosed with chronic obstructive pulmonary disease (COPD). Patients and methods We retrospectively enrolled patients with COPD who underwent symptom assessment and comprehensive pulmonary function tests at the First Affiliated Hospital of Guangzhou Medical University between August 2017 and March 2022. The patients were categorized into two groups based on age: a young COPD group (aged 20–50 years) and an old COPD group (aged > 50 years). Results A total of 1282 patients with COPD were included in the study, with 76 young COPD patients and 1206 old COPD patients. Young COPD patients exhibited a higher likelihood of being asymptomatic, lower rates of smoking, and a lower smoking index compared to old COPD patients. Although young COPD patients had higher median post-bronchodilator forced expiratory volume in 1 s (post-BD FEV1) (1.4 vs.1.2 L, P = 0.019), diffusing capacity of the lung for carbon monoxide (DLCO) (7.2 vs. 4.6, P 120%) between two groups. Surprisingly, the prevalence of reduced DLCO was found to be 71.1% in young COPD, although lower than in old COPD (85.2%). Conclusion Young COPD showed fewer respiratory symptoms, yet displayed a similar severity distribution by GOLD categories. Furthermore, a majority of them demonstrated lung hyperinflation and reduced DLCO. These results underscore the importance of a comprehensive assessment of lung function in young COPD patients.

Abstract Background To understand the accuracy of volume calibration syringes used in China and compare the difference between new and old volume calibration syringes, technical testing was performed on volume calibration syringes in clinical lung function instruments. Materials and methods A standard validator device (Model 1180, Hans Rudolph, USA) was used to perform leak testing and volume accuracy testing for calibration syringes. Sixteen volume calibration syringes from 8 brands (CareFusion in Germany, Vyaire in Germany, Yaeger in Germany, Vitalograph in the United Kingdom, MGC Diagnostics in the United States, U-Breath in Zhejiang, China, Wendi in Ningbo, Zhejiang, and Boya in Ningbo, China) were tested. Results A total of 75% (12/16) of the volume calibration syringes passed the pressure decay leak test, 69% (11/16) of the volume calibration syringes passed the volume accuracy and repeatability test, and 56% (9/16) passed both tests; there was no significant difference in the total passing of the new and old volume calibration syringe quality tests (P > 0.05). Conclusions A standard validator device should be used for both leakage tests and volume accuracy and repeatability tests to ensure the reliability of volume calibration syringes. It is suggested that the quality verification of volume calibration syringes should be regularly conducted to ensure the accuracy of the pulmonary function tests.

Abstract Background The spirometer is an important element in lung function examinations, and its accuracy is directly related to the accuracy of the results of these examinations and to the diagnosis and treatment of diseases. Our aim was to conduct a performance analysis of the detection techniques of differential pressure and ultrasonic portable spirometers commonly used in China. Methods A standard flow/volume simulator was used to analyze the performance (accuracy, repeatability, linearity, impedance, and so on) of portable spirometers, 4 imported and 6 domestic, based on 13 curves generated by different air sources in the ISO 26782:2009 standard. A Bland–Altman diagram was used to evaluate the consistency between the values measured by the spirometers and the simulator. Results The pass rates for accuracy, repeatability, linearity, and impedance for the 10 different portable spirometers were 50%, 100%, 70%, and 70%, respectively. Only 30% (3/10) of the spirometers—2 domestic and 1 imported—met all standards of quality and performance evaluation, while the rest were partially up to standard. In the consistency evaluation, only 3 spirometers were within both the consistency standard range and the acceptability range. Conclusion The quality and performance of different types of portable spirometers commonly used in the clinic differ. The use of a standard flow/volume simulator is helpful for the standard evaluation of the technical performance of spirometers.

Abstract Background Small plateau (SP) on the flow-volume curve was found in parts of patients with suspected asthma or upper airway abnormalities, but it lacks clear scientific proof. Therefore, we aimed to characterize its clinical features. Methods We involved patients by reviewing the bronchoprovocation test (BPT) and bronchodilator test (BDT) completed between October 2017 and October 2020 to assess the characteristics of the sign. Patients who underwent laryngoscopy were assigned to perform spirometry to analyze the relationship of the sign and upper airway abnormalities. SP-Network was developed to recognition of the sign using flow-volume curves. Results Of 13,661 BPTs and 8,168 BDTs completed, we labeled 2,123 (15.5%) and 219 (2.7%) patients with the sign, respectively. Among them, there were 1,782 (83.9%) with the negative-BPT and 194 (88.6%) with the negative-BDT. Patients with SP sign had higher median FVC and FEV1% predicted (both P

Abstract Background Chronic obstructive pulmonary disease (COPD) is the fifth leading cause of death in China with a reported prevalence of 8.2% people aged ≥40 years. It is recommended that Chinese physicians follow Global Initiative for Chronic Obstructive Lung Disease (GOLD) and national guidelines, yet many patients with COPD in China remain undiagnosed. Furthermore, missed diagnoses and a lack of standardized diagnosis and treatment remain significant problems. The situation is further complicated by a lack of large-scale, long-term, prospective studies of real-world outcomes, including exacerbation rates, disease severity, efficacy of treatment, and compliance of COPD patients in China. Methods/design The REALizing and improving management of stable COPD in China (REAL) study is a 52-week multi-center, prospective, observational trial. REAL aims to recruit approximately 5000 outpatients aged ≥40 years with a clinical diagnosis of COPD per GOLD 2016. Outpatients will be consecutively recruited from approximately 50 tertiary and secondary hospitals randomly selected across six geographic regions to provide a representative population. Patients will receive conventional medical care as determined by their treating physicians. The primary objective is to evaluate COPD patient outcomes including lung function, health status, exacerbations, hospitalization rate, and dyspnea following 1 year of current clinical practice. Secondary objectives are to assess disease severity, treatment patterns, adherence to medication, and associated risk factors. Data will be collected at two study visits, at patients’ usual care visits, and by telephone interview every 3 months. Discussion Knowledge of COPD among physicians in China is poor. The REAL study will provide reliable information on COPD management, outcomes, and risk factors that may help improve the standard of care in China. Patient recruitment began on 30 June 2017 and the estimated primary completion date is 30 July 2019. Trial registration ClinicalTrials.gov identifier: NCT03131362. Registered on 20 March 2017.