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Henry C, Biardel S, Boucher M, Godbout K, Chakir J, Côté A, Laviolette M, Bossé Y. Bronchial thermoplasty attenuates bronchodilator responsiveness. Respir Med 2023; 217:107340. [PMID: 37422022 DOI: 10.1016/j.rmed.2023.107340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 05/31/2023] [Accepted: 06/25/2023] [Indexed: 07/10/2023]
Abstract
INTRODUCTION Bronchial thermoplasty is an effective intervention to improve respiratory symptoms and to reduce the rate of exacerbations in uncontrolled severe asthma. A reduction in airway smooth muscle is arguably the most widely discussed mechanisms accounting for these clinical benefits. Yet, this smooth muscle reduction should also translate into an impaired response to bronchodilator drugs. This study was designed to address this question. METHODS Eight patients with clinical indication for thermoplasty were studied. They were uncontrolled severe asthmatics despite optimal environmental control, treatment of comorbidities, and the use of high-dose inhaled corticosteroids and long-acting β2-agonists. Lung function measured by spirometry and respiratory mechanics measured by oscillometry were examined pre- and post-bronchodilator (salbutamol, 400 μg), both before and at least 1 year after thermoplasty. RESULTS Consistent with previous studies, thermoplasty yielded no benefits in terms of baseline lung function and respiratory mechanics, despite improving symptoms based on two asthma questionnaires (ACQ-5 and ACT-5). The response to salbutamol was also not affected by thermoplasty based on spirometric readouts, including forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), and FEV1/FVC ratio. However, a significant interaction was observed between thermoplasty and salbutamol for two oscillometric readouts, namely reactance at 5 Hz (Xrs5) and reactance area (Ax), showing an attenuated response to salbutamol after thermoplasty. CONCLUSIONS Thermoplasty attenuates the response to a bronchodilator. We argue that this result is a physiological proof of therapeutic efficacy, consistent with the well-described effect of thermoplasty in reducing the amount of airway smooth muscle.
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Affiliation(s)
- Cyndi Henry
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ) - Université Laval, Québec, Canada
| | - Sabrina Biardel
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ) - Université Laval, Québec, Canada
| | - Magali Boucher
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ) - Université Laval, Québec, Canada
| | - Krystelle Godbout
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ) - Université Laval, Québec, Canada
| | - Jamila Chakir
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ) - Université Laval, Québec, Canada
| | - Andréanne Côté
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ) - Université Laval, Québec, Canada
| | - Michel Laviolette
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ) - Université Laval, Québec, Canada
| | - Ynuk Bossé
- Institut Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ) - Université Laval, Québec, Canada.
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Baydur A, Barbers R, May D. Effect of bronchial thermoplasty on static and dynamic lung compliance and resistance in patients with severe persistent asthma. Respir Med 2023; 217:107341. [PMID: 37429559 DOI: 10.1016/j.rmed.2023.107341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 06/21/2023] [Accepted: 06/25/2023] [Indexed: 07/12/2023]
Abstract
RATIONALE Bronchial thermoplasty (BT) reduces severity and frequency of bronchoconstriction and symptoms in severe, persistent asthmatics although it is usually not associated with change in spirometric variables. Other than spirometry. there are almost no data on changes in lung mechanics following BT. OBJECTIVE To assess lung static and dynamic lung compliance (Cst,L and Cdyn,L, respectively) and static and dynamic lung resistance (Rst,L and Rdyn,L, respectively) before and after BT in severe asthmatics using the esophageal balloon technique. METHODS Rdyn,L and Cdyn,L were measured at respiratory frequencies up to 145 breaths/min, using the esophageal balloon technique in 7 patients immediately before and 12-50 weeks after completing a series of 3 BT sessions. RESULTS All patients experienced improved symptoms within a few weeks following completion of BT. Pre-BT, all patients exhibited frequency dependency of lung compliance, with mean Cdyn,L decreasing to 63% of Cst,L at maximum respiratory rates. Post-BT, Cst,L did not change significantly from pre-thermoplasty values, while Cdyn,L diminished to 62%% of Cst,L. In 4 of 7 patients, post-BT values of Cdyn,L were consistently higher than pre-BT over the range of respiratory rates. RL in 4 of 7 patients during quiet breathing and at higher respiratory frequencies decreased following BT. CONCLUSIONS Patients with severe persistent asthma exhibit increased resting lung resistance and frequency dependence of compliance, the magnitudes of which are ameliorated in some patients following bronchial thermoplasty and associated with variable change in frequency dependence of lung resistance. These findings are related to asthma severity and may be related to the heterogeneous and variable nature of airway smooth muscle modeling and its response to BT.
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Affiliation(s)
- Ahmet Baydur
- Division of Pulmonary, Critical Care and Sleep Medicine, Keck School of Medicine, University of Southern California and Keck Medical Center, Los Angeles, CA, USA.
| | - Richard Barbers
- Division of Pulmonary, Critical Care and Sleep Medicine, Keck School of Medicine, University of Southern California and Keck Medical Center, Los Angeles, CA, USA
| | - Darren May
- Division of Pulmonary, Critical Care and Sleep Medicine, Keck School of Medicine, University of Southern California and Keck Medical Center, Los Angeles, CA, USA
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Menzella F, Antonicelli L, Cottini M, Imeri G, Corsi L, Di Marco F. Oscillometry in severe asthma: the state of the art and future perspectives. Expert Rev Respir Med 2023; 17:563-575. [PMID: 37452692 DOI: 10.1080/17476348.2023.2237872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 07/07/2023] [Accepted: 07/14/2023] [Indexed: 07/18/2023]
Abstract
INTRODUCTION Approximately 3-10% of people with asthma have severe asthma (SA). Patients with SA have greater impairment in daily life and much higher costs. Even if asthma affects the entire bronchial tree, small airways have been recognized as the major site of airflow limitation. There are several tools for studying small airway dysfunction (SAD), but certainly the most interesting is oscillometry. Despite several studies, the clinical usefulness of oscillometry in asthma is still in question. This paper aims to provide evidence supporting the use of oscillometry to improve the management of SA in clinical practice. AREAS COVERED In the ATLANTIS study, SAD was strongly evident across all severity. Various tools are available for evaluation of SAD, and certainly an integrated use of these can provide complete and detailed information. However, the most suitable method is oscillometry, implemented for clinical routine by using either small pressure impulses or small pressure sinusoidal waves. EXPERT OPINION Oscillometry, despite its different technological implementations is the best tool for determining the impact of SAD on asthma and its control. Oscillometry will also be increasingly useful for choosing the appropriate drug, and there is ample room for a more widespread diffusion in clinical practice.
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Affiliation(s)
| | | | | | - Gianluca Imeri
- Respiratory Unit, ASST Papa Giovanni XXIII Hospital, Bergamo, Italy
| | - Lorenzo Corsi
- Pulmonology Unit, S. Valentino Hospital, Treviso, Italy
| | - Fabiano Di Marco
- Respiratory Unit, ASST Papa Giovanni XXIII Hospital, Bergamo, Italy
- Department of Health Sciences, University of Milan, Bergamo, Italy
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Rajan A, Bennetts K, Langton D. Plethysmography Derived Gas Trapping Lacks Utility in Predicting Response to Bronchial Thermoplasty. ERJ Open Res 2022; 8:00690-2021. [PMID: 35539441 PMCID: PMC9081540 DOI: 10.1183/23120541.00690-2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 03/04/2022] [Indexed: 12/03/2022] Open
Abstract
There is a paucity of literature on measurable baseline parameters predicting response and guiding selection for bronchial thermoplasty. This study examines whether baseline gas trapping, as assessed by plethysmography, is associated with a response to bronchial thermoplasty at 12 months. 43 consecutive patients with severe asthma (mean±sd age 57.6±13.3 years) were evaluated at baseline and 12 months post bronchial thermoplasty. Data collected at both time points included spirometry, body plethysmography and four clinical outcome measures, namely Asthma Control Questionnaire (ACQ) score, annual exacerbation frequency, maintenance oral corticosteroid requirement and short-acting β-agonist use. At baseline, participants had severe airflow obstruction (forced expiratory volume in 1 s 49.1±15.8%) with marked gas trapping (residual volume (RV) 150.3±40.8%, RV/total lung capacity (TLC) 51.3±10.5%), poor symptom control (ACQ 3.3±1.0) and frequent exacerbations (median 4, interquartile range 8). 12 months after bronchial thermoplasty, significant improvements were observed in all four clinical outcome measures. However, baseline RV and RV/TLC were not significantly associated with changes in ACQ nor any other clinical outcome measure, and changes in RV and RV/TLC did not significantly correlate with a change in any clinical outcome measure. Plethysmography-derived gas trapping does not demonstrate utility in predicting response and guiding selection for bronchial thermoplasty. An improvement in gas trapping was not associated with positive clinical outcomes, suggesting that this may not be the dominant mode of action of bronchial thermoplasty in generating clinical improvement. This study examined whether measuring gas trapping by plethysmography could be used to predict response to bronchial thermoplasty; no association was foundhttps://bit.ly/3tJN1X8
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Goorsenberg AWM, d'Hooghe JNS, Srikanthan K, Ten Hacken NHT, Weersink EJM, Roelofs JJTH, Kemp SV, Bel EH, Shah PL, Annema JT, Bonta PI. Bronchial Thermoplasty Induced Airway Smooth Muscle Reduction and Clinical Response in Severe Asthma. The TASMA Randomized Trial. Am J Respir Crit Care Med 2021; 203:175-184. [PMID: 32721210 DOI: 10.1164/rccm.201911-2298oc] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Rationale: Bronchial thermoplasty (BT) is a bronchoscopic treatment for severe asthma targeting airway smooth muscle (ASM). Observational studies have shown ASM mass reduction after BT, but appropriate control groups are lacking. Furthermore, as treatment response is variable, identifying optimal candidates for BT treatment is important.Objectives: First, to assess the effect of BT on ASM mass, and second, to identify patient characteristics that correlate with BT response.Methods: Patients with severe asthma (n = 40) were randomized to immediate (n = 20) or delayed (n = 20) BT treatment. Before randomization, clinical, functional, blood, and airway biopsy data were collected. In the delayed control group, reassessment, including biopsies, was performed after 6 months of standard clinical care, followed by BT. In both groups, post-BT data including biopsies were obtained after 6 months. ASM mass (% positive desmin or α-smooth muscle actin area in the total biopsy) was calculated with automated digital analysis software. Associations between baseline characteristics and Asthma Control Questionnaire and Asthma Quality of Life Questionnaire (AQLQ) improvement were explored.Measurements and Main Results: Median ASM mass decreased by >50% in the immediate BT group (n = 17) versus no change in the delayed control group (n = 19) (P = 0.0004). In the immediate group, Asthma Control Questionnaire scores improved with -0.79 (interquartile range [IQR], -1.61 to 0.02) compared with 0.09 (IQR, -0.25 to 1.17) in the delayed group (P = 0.006). AQLQ scores improved with 0.83 (IQR, -0.15 to 1.69) versus -0.02 (IQR, -0.77 to 0.75) (P = 0.04). Treatment response in the total group (n = 35) was positively associated with serum IgE and eosinophils but not with baseline ASM mass.Conclusions: ASM mass significantly decreases after BT when compared with a randomized non-BT-treated control group. Treatment response was associated with serum IgE and eosinophil levels but not with ASM mass.
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Affiliation(s)
| | | | - Karthikan Srikanthan
- Department of Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| | - Nick H T Ten Hacken
- Department of Respiratory Medicine, Royal Brompton Hospital, London, United Kingdom
| | | | - Joris J T H Roelofs
- Department of Pulmonology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Samuel V Kemp
- Department of Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands.,National Heart & Lung Institute, Imperial College, London, United Kingdom; and
| | | | - Pallav L Shah
- Department of Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands.,National Heart & Lung Institute, Imperial College, London, United Kingdom; and.,Department of Pulmonology, Chelsea & Westminster Hospital, London, United Kingdom
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Ravi A, Goorsenberg AWM, Dijkhuis A, Dierdorp BS, Dekker T, van Weeghel M, Sabogal Piñeros YS, Shah PL, Ten Hacken NHT, Annema JT, Sterk PJ, Vaz FM, Bonta PI, Lutter R. Metabolic differences between bronchial epithelium from healthy individuals and patients with asthma and the effect of bronchial thermoplasty. J Allergy Clin Immunol 2021; 148:1236-1248. [PMID: 33556463 DOI: 10.1016/j.jaci.2020.12.653] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 11/23/2020] [Accepted: 12/01/2020] [Indexed: 01/27/2023]
Abstract
BACKGROUND Asthma is a heterogeneous disease with differences in onset, severity, and inflammation. Bronchial epithelial cells (BECs) contribute to asthma pathophysiology. OBJECTIVE We determined whether transcriptomes of BECs reflect heterogeneity in inflammation and severity in asthma, and whether this was affected in BECs from patients with severe asthma after their regeneration by bronchial thermoplasty. METHODS RNA sequencing was performed on BECs obtained by bronchoscopy from healthy controls (n = 16), patients with mild asthma (n = 17), patients with moderate asthma (n = 5), and patients with severe asthma (n = 17), as well as on BECs from treated and untreated airways of the latter (also 6 months after bronchial thermoplasty) (n = 23). Lipidome and metabolome analyses were performed on cultured BECs from healthy controls (n = 7); patients with severe asthma (n = 9); and, for comparison, patients with chronic obstructive pulmonary disease (n = 7). RESULTS Transcriptome analysis of BECs from patients showed a reduced expression of oxidative phosphorylation (OXPHOS) genes, most profoundly in patients with severe asthma but less profoundly and more heterogeneously in patients with mild asthma. Genes related to fatty acid metabolism were significantly upregulated in asthma. Lipidomics revealed enhanced levels of lipid species (phosphatidylcholines, lysophosphatidylcholines. and bis(monoacylglycerol)phosphate), whereas levels of OXPHOS metabolites were reduced in BECs from patients with severe asthma. BECs from patients with mild asthma characterized by hyperresponsive production of mediators implicated in neutrophilic inflammation had decreased expression of OXPHOS genes compared with that in BECs from patients with mild asthma with normoresponsive production. BECs obtained after thermoplasty had significantly increased expression of OXPHOS genes and decreased expression of fatty acid metabolism genes compared with BECs obtained from untreated airways. CONCLUSION BECs in patients with asthma are metabolically different from those in healthy individuals. These differences are linked with inflammation and asthma severity, and they can be reversed by bronchial thermoplasty.
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Affiliation(s)
- Abilash Ravi
- Department of Respiratory Medicine, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Department of Experimental Immunology, Amsterdam Infection and Immunity Institute, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
| | - Annika W M Goorsenberg
- Department of Respiratory Medicine, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Annemiek Dijkhuis
- Department of Experimental Immunology, Amsterdam Infection and Immunity Institute, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Barbara S Dierdorp
- Department of Experimental Immunology, Amsterdam Infection and Immunity Institute, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Tamara Dekker
- Department of Experimental Immunology, Amsterdam Infection and Immunity Institute, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Michel van Weeghel
- Laboratory Genetic Metabolic Diseases, Core Facility Metabolomics, Department of Clinical Chemistry, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Yanaika S Sabogal Piñeros
- Department of Respiratory Medicine, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Department of Experimental Immunology, Amsterdam Infection and Immunity Institute, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Pallav L Shah
- Royal Brompton Hospital, London, United Kingdom; National Heart and Lung Institute, Imperial College, London, United Kingdom; Chelsea and Westminster Hospital, London, United Kingdom
| | - Nick H T Ten Hacken
- Department of Pulmonology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Jouke T Annema
- Department of Respiratory Medicine, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Peter J Sterk
- Department of Respiratory Medicine, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Frédéric M Vaz
- Laboratory Genetic Metabolic Diseases, Core Facility Metabolomics, Department of Clinical Chemistry, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Peter I Bonta
- Department of Respiratory Medicine, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - René Lutter
- Department of Respiratory Medicine, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Department of Experimental Immunology, Amsterdam Infection and Immunity Institute, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
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Marinakis G, Paraschos M, Patrani M, Tsoutsouras T, Vassiliou M. Non-interventional monitoring of expiratory flow limitation during experimental mechanical ventilation. ERJ Open Res 2021; 7:00264-2020. [PMID: 33532479 PMCID: PMC7836650 DOI: 10.1183/23120541.00264-2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 09/25/2020] [Indexed: 11/17/2022] Open
Abstract
Background Expiratory flow limitation (EFL) is common among patients in the intensive care unit under mechanical ventilation (MV) and may have significant clinical consequences. In the present study, we examine the possibility of non-interventional detection of EFL during experimental MV. Methods Eight artificially ventilated New Zealand rabbits were included in the experiments. EFL was induced during MV by application of negative expiratory pressure (−5, −8 and −10 hPa) and detected by the negative expiratory pressure technique. Airway pressure (Paw) and gas flow (V′) were digitally recorded and processed off-line for the evaluation of respiratory mechanics. The method is based on the computation and monitoring of instantaneous respiratory resistance Rrs(t). The resistive pressure (Paw,res(t)) is calculated by subtracting from Paw its elastic component and the end-expiratory pressure, as assessed by linear regression. Then, Rrs(t) is computed as the instant ratio Paw,res(t)/V′(t). Results Two completely different patterns of expiratory Rrs(t) separate the cases with EFL from those without EFL. Small and random fluctuations are noticed when EFL is absent, whereas the onset of EFL is accompanied by an abrupt and continuous rise in Rrs(t), towards the end of expiration. Thus, EFL is not only detected but may also be quantified from the volume still to be expired at the time EFL occurs. Conclusion The proposed technique is a simple, accurate and non-interventional tool for EFL monitoring during MV. Respiratory system resistance in expiratory flow limitation during mechanical ventilationhttps://bit.ly/34hU6Bv
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Affiliation(s)
- Giorgos Marinakis
- Dept of Critical Care Medicine, General Hospital of Athens, "Korgialenio - Benakio" Hellenic Red Cross, Athens, Greece
| | - Michael Paraschos
- Dept of Critical Care Medicine, General Hospital of Athens, "Korgialenio - Benakio" Hellenic Red Cross, Athens, Greece
| | - Maria Patrani
- Dept of Critical Care Medicine, General Hospital of Athens, "Korgialenio - Benakio" Hellenic Red Cross, Athens, Greece
| | - Theodoros Tsoutsouras
- Dept of Critical Care Medicine, General Hospital of Athens, "Korgialenio - Benakio" Hellenic Red Cross, Athens, Greece
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[Application of a multiple linear regression model of FEV1 in pulmonary function test]. NAN FANG YI KE DA XUE XUE BAO = JOURNAL OF SOUTHERN MEDICAL UNIVERSITY 2020; 40:1799-1803. [PMID: 33380396 PMCID: PMC7835695 DOI: 10.12122/j.issn.1673-4254.2020.12.15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
OBJECTIVE To construct a multiple linear regression model of forced expiratory volume in 1 second (FEV1) for estimating FEV1 in special populations unable to receive or uncooperative in pulmonary ventilation function tests. METHODS The multiple linear regression model of FEV1 was constructed based on the data of 813 individuals undergoing pulmonary function tests in First Affiliated Hospital of Zhejiang Chinese Medical University between September, 2017 and September, 2019, and was validated using the data of another 94 individuals from the same hospital between January and July, 2020. FEV1 of the individuals was measured by pulmonary ventilation function test, and respiratory resistance (Rrs) was measured using forced oscillation technique (FOT). Pearson correlation analysis was used to assess the correlation between the factors, and the model equation was established by multiple stepwise regression analysis. The calculated FEV1 based on the model was compared with the measured FEV1 among both the individuals included for modeling and validation. RESULTS FEV1 was not significantly correlated with BMI (r=-0.026, P=0.457), poorly correlated with body mass (r=0.382, P=0.000), positively correlated with height (r=0.723, P=0.000), and negatively correlated with Rrs (r=-0.503, P=0.000) with an obvious gender differences (t=18.517, P=0.000). FEV1 was positively correlated with age among individuals below 25 years of age (r=0.578, P=0.000) and was negatively correlated with age among those beyond or at the age of 25 (r=-0.589, P=0.000). For individuals beyond or at the age of 25 years, the variables of height, gender, age and Rrs were included in the model, and the calculated FEV1 did not differ significantly from the measured values in either the modeling sample (n=751; t=1.293, P=0.196) or the verification sample (n=83;t=-1.736, P=0.086), and the two values were well correlated in the verification sample (r=0.891, P=0.000). For individuals below 25 years, only height was included in the model, and the calculated FEV1 and the measured values showed no significant difference in the modeling sample (n=62; t=-0.009, P=0.993) or the verification sample (n=11; t=-0.635, P=0.540) with a good correlation in the verification sample (r=0.795, P=0.003). CONCLUSIONS The multiple linear regression model for calculating FEV1 constructed in this study is suitable for clinical application.
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