Value of preoperative evaluation of FEV1 in patients with destroyed lung undergoing pneumonectomy - a 20-year real-world study.

BACKGROUND: Clinical guidelines recommend a preoperative forced expiratory volume in one second (FEV1) of > 2 L as an indication for left or right pneumonectomy. This study compares the safety and long-term prognosis of pneumonectomy for destroyed lung (DL) patients with FEV1 ≤ 2 L or > 2 L. METHODS: A total of 123 DL patients who underwent pneumonectomy between November 2002 and February 2023 at the Department of Thoracic Surgery, Beijing Chest Hospital were included. Patients were sorted into two groups: the FEV1 > 2 L group (n = 30) or the FEV1 ≤ 2 L group (n = 96). Clinical characteristics and rates of mortality, complications within 30 days after surgery, long-term mortality, occurrence of residual lung infection/tuberculosis (TB), bronchopleural fistula/empyema, readmission by last follow-up visit, and modified Medical Research Council (mMRC) dyspnea scores were compared between groups. RESULTS: A total of 96.7% (119/123) of patients were successfully discharged, with 75.6% (93/123) in the FEV1 ≤ 2 L group. As compared to the FEV1 > 2 L group, the FEV1 ≤ 2 L group exhibited significantly lower proportions of males, patients with smoking histories, patients with lung cavities as revealed by chest imaging findings, and patients with lower forced vital capacity as a percentage of predicted values (FVC%pred) (P values of 0.001, 0.027, and 0.023, 0.003, respectively). No significant intergroup differences were observed in rates of mortality within 30 days after surgery, incidence of postoperative complications, long-term mortality, occurrence of residual lung infection/TB, bronchopleural fistula/empyema, mMRC ≥ 1 at the last follow-up visit, and postoperative readmission (P > 0.05). CONCLUSIONS: As most DL patients planning to undergo left/right pneumonectomy have a preoperative FEV1 ≤ 2 L, the procedure is generally safe with favourable short- and long-term prognoses for these patients. Consequently, the results of this study suggest that DL patient preoperative FEV1 > 2 L should not be utilised as an exclusion criterion for pneumonectomy.

COPD exacerbations and patient-reported outcomes according to post-bronchodilator FEV1 - a post-hoc analysis of pooled data.

BACKGROUND: Management strategies of chronic obstructive pulmonary disease (COPD) need to be tailored to the forced expiratory volume in one second (FEV1), exacerbations, and patient-reported outcomes (PROs) of individual patients. In this study, we analyzed the association and correlation between the FEV1, exacerbations, and PROs of patients with stable COPD. METHODS: This was a post-hoc analysis of pooled data from two cross-sectional studies that were previously conducted in Malaysia from 2017 to 2019, the results of which had been published separately. The parameters measured included post-bronchodilator FEV1 (PB-FEV1), exacerbations, and scores of modified Medical Research Council (mMRC), COPD Assessment Test (CAT), and St George's Respiratory Questionnaire for COPD (SGRQ-c). Descriptive, association, and correlation statistics were used. RESULTS: Three hundred seventy-four patients were included in the analysis. The PB-FEV1 predicted was < 30% in 85 (22.7%), 30-49% in 142 (38.0%), 50-79% in 111 (29.7%), and ≥ 80% in 36 (9.6%) patients. Patients with PB-FEV1 < 30% predicted had significantly more COPD exacerbations than those with PB-FEV1 30-49% predicted (p < 0.001), 50-79% predicted (p < 0.001), and ≥ 80% predicted (p = 0.002). The scores of mMRC, CAT, and SGRQ-c were not significantly higher in patients with more severe airflow limitation based on PB-FEV1 (p = 0.121-0.271). The PB-FEV1 predicted had significant weak negative correlations with exacerbations (r = - 0.182, p < 0.001), mMRC (r = - 0.121, p = 0.020), and SGRQ-c scores (r = - 0.114, p = 0.028). There was a moderate positive correlation between COPD exacerbations and scores of mMRC, CAT, and SGRQ-c (r = 0.407-0.482, all p < 0.001). There were significant strong positive correlations between mMRC score with CAT (r = 0.727) and SGRQ-c scores (r = 0.847), and CAT score with SGRQ-c score (r = 0.851) (all p < 0.001). CONCLUSIONS: In COPD patients, different severity of airflow limitation was not associated with significant differences in the mMRC, CAT, and SGRQ-c scores. Exacerbations were significantly more frequent in patients with very severe airflow limitation only. The correlation between airflow limitation with exacerbations, mMRC, and SGRQ-c was weak.

Immediate complications and flow volume changes during treatment phases of bronchial thermoplasty: a single-center descriptive study.

INTRODUCTION: Bronchial thermoplasty (B.T.) is a therapeutic bronchoscopic procedure in which controlled thermal energy is applied to the airway wall to decrease smooth muscle mass. Immediate complications of B.T. include acute exacerbation of bronchial asthma, upper and lower respiratory tract infection, hemoptysis, among others. Our study assessed these immediate adverse events and the changes in forced expiratory volume in one second (FEV1%) measured four hours after each procedure from baseline. The study also aimed to examine the number of activations during each cycle of treatment and its correlation to the corresponding change in FEV1% from baseline. METHODS: A case-series analysis of 17 patients who underwent B.T. between 2014 and 2019 was done. Demographic, clinical characteristics, including pre and post-BT FEV1% measures, and the number of activations were obtained. RESULTS: Acute exacerbation of asthma was the commonest complication accounting for 33%, 57%, and 75% after BT1, BT2, and BT3, respectively. There was deterioration in FEV1% after each treatment phase, the most significant being in BT3. There was no correlation between the number of heat activations with the change in FEV1% from baseline. CONCLUSION: The number of activations in B.T. does not correlate with the immediate deterioration in FEV1%, although exacerbation of asthma is the commonest complication post-B.T.

The effect of TGF-ß1 polymorphisms on pulmonary disease progression in patients with cystic fibrosis.

BACKGROUND: Transforming Growth Factor-ß1 (TGF-ß1) is a genetic modifier in patients with cystic fibrosis (CF). Several single nucleotide polymorphisms (SNPs) of TGF-ß1 are associated with neutrophilic inflammation, lung fibrosis and loss of pulmonary function. AIM: The aim of this study was to assess the relationship between genetic TGF-ß1 polymorphisms and pulmonary disease progression in CF patients. Furthermore, the effect of TGF-ß1 polymorphisms on inflammatory cytokines in sputum was investigated. METHODS: 56 CF-patients and 62 controls were genotyped for three relevant SNPs in their TGF-ß1 sequence using the SNaPshot® technique. Individual "slopes" in forced expiratory volume in 1 s (FEV1) for all patients were calculated by using documented lung function values of the previous five years. The status of Pseudomonas aeruginosa (Pa) infection was determined. Sputum concentrations of the protease elastase, the serine protease inhibitor elafin and the cytokines IL-1ß, IL-8, IL-6, TNF-α were measured after a standardized sputum induction and processing. RESULTS: The homozygous TT genotype at codon 10 was associated with a lower rate of chronic Pa infection (p < 0.05). The heterozygous GC genotype at codon 25 was associated with lower lung function decline (p < 0.05). Patients with homozygous TT genotype at the promotor SNP showed higher levels of TNF-α (p < 0,05). Higher levels of TGF-ß1 in plasma were associated with a more rapid FEV1 decline over five years (p < 0.05). CONCLUSIONS: Our results suggest that polymorphisms in the TGF-ß1 gene have an effect on lung function decline, Pa infection as well as levels of inflammatory cytokines. Genotyping these polymorphisms could potentially be used to identify CF patients with higher risk of disease progression. TGF-ß1 inhibition could potentially be developed as a new therapeutic option to modulate CF lung disease.

Association between pulmonary function and renal function: findings from China and Australia.

BACKGROUND: The relationship between obstructive lung function and impaired renal function is unclear. This study investigated the dose-response relationship between obstructive lung function and impaired renal function. METHODS: Two independent cross-sectional studies with representative sampling were applied. 1454 adults from rural Victoria, Australia (1298 with normal renal function, 156 with impaired renal function) and 5824 adults from Nanjing, China (4313 with normal renal function, 1511 with impaired renal function). Pulmonary function measurements included forced expiratory volume in one second (FEV1) and forced vital capacity (FVC). Estimated glomerular filtration rate (eGFR), and impaired renal function marked by eGFR <60 mL/min/1.73m2 were used as outcome. RESULTS: eGFR increased linearly with FEV1 in Chinese participants and with FVC in Australians. A non-linear relationship with peaked eGFR was found for FEV1 at 2.65 L among Australians and for FVC at 2.78 L among Chinese participants, respectively. A non-linear relationship with peaked eGFR was found for the predicted percentage value of forced expiratory volume in 1 s (PFEV1) at 81-82% and for the predicted percentage value of forced vital capacity (PFVC) at 83-84% among both Chinese and Australian participants, respectively. The non-linear dose-response relationships between lung capacity measurements (both for FEV1 and FVC) and risk of impaired renal function were consistently identified in both Chinese and Australian participants. An increased risk of impaired renal function was found below 3.05 L both for FEV1 and FVC, respectively. The non-linear relationship between PFEV and PVC and the risk of impaired renal function were consistently identified in both Chinese and Australian participants. An increased risk of impaired renal function was found below 76-77% for PFEV1 and 79-80% for PFVC, respectively. CONCLUSIONS: In both Australian and Chinese populations, the risk of impaired renal function increased both with FEV1 and FVC below 3.05 L, with PFEV1 below 76-77% or with PFVC below 79-80%, respectively. Obstructive lung function was associated with increased risk of reduced renal function. The screen for impaired renal function in patients with obstructive lung disease might be useful to ensure there was no impaired renal function before the commencement of potentially nephrotoxic medication where indicated (eg diuretics).

Effects of aerobic exercise-based pulmonary rehabilitation on quality of life in pediatric asthma: A systematic review and meta-analysis.

BACKGROUND: Pediatric asthma poses a significant global health burden, impacting the well-being and daily lives of affected children. Aerobic exercise-based pulmonary rehabilitation emerges as a promising intervention to address the multifaceted challenges faced by pediatric asthma patients. OBJECTIVES: The purpose of this systematic review and meta-analysis was to comprehensively evaluate the effects of aerobic exercise-based pulmonary rehabilitation on pulmonary function and quality of life in pediatric asthma patients. METHODS: Randomized controlled trials (RCTs) involving pediatric participants (5-18 years) were included. Aerobic exercise program-based pulmonary rehabilitation interventions were assessed for their impact on actual and percentage predicted values of lung volumes and flow rates such as forced vital capacity (FVC), maximum mid-expiratory flow (FEF25-75), peak expiratory flow (PEF), forced expiratory volume in one second (FEV1), FEV1/FVC, and on quality of life (QoL) measures. A systematic search of databases, hand-searching, and consultation with experts identified relevant studies. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines guided study selection, data extraction, and quality assessment. RESULTS: The systematic review included 20 studies with diverse exercise interventions and outcomes. The meta-analysis using fixed-effects model showed that there was a significant improvement in FVC (% predicted) [SMD= 0.30, 95 %CI: 0.13, 0.48] and FEF25-75 (% predicted) [SMD= 0.31, 95 %CI: 0.03, 0.58] in the experimental group compared with the control group. Furthermore, using a random-effects model involving 12 studies, significant increases in the QoL [SMD= 0.70, 95 %CI: 0.14, 1.26] were found in the exercise group. Due to inter-study heterogeneity, additional analyses were conducted. Publication bias analysis indicated robustness, with no significant asymmetry in funnel plots. CONCLUSION: Aerobic exercise-based pulmonary rehabilitation significantly enhances pulmonary function and quality of life in pediatric asthma patients. The findings, supported by improvements in FVC and FEF25-75, demonstrate the efficacy of these interventions. Quality of life measures also showed notable improvements. Despite inter-study heterogeneity, the results are robust, suggesting that aerobic exercise should be considered a valuable non-pharmacological strategy in managing pediatric asthma.

A comparison of clinic and home spirometry as longtudinal outcomes in cystic fibrosis.

BACKGROUND: The COVID-19 pandemic has accelerated the transition to telehealth, including the use of home spirometry in cystic fibrosis. Evaluating the accuracy and precision of longitudinal home spirometry is a requisite for telehealth-based research. This secondary analysis of a CF study (eICE) evaluates whether there are cross-sectional or longitudinal differences between home and clinic spirometry. METHODS: Participants age ≥14 years with ppFEV1>25 were recruited from 2011-2015, issued a home spirometer, and asked to complete spirometry efforts twice per week for one year. Clinic spirometry was collected at baseline and every three months. Cross-sectional differences between clinic spirometry and the closest home spirometry measurement were analyzed. Longitudinally, we apply 5 methods to analyze the precision of home spirometry, and differences between clinic vs. home data. RESULTS: Home spirometry is estimated to be 2.0 (95% CI: 0.3, 3.5) percentage points lower than clinic spirometry cross-sectionally. Longitudinally, the estimates of 12-month change in home spirometry varied by analysis method from -2.6 to -1.0 ppFEV1/ year, with precision markedly different. However, home spirometry change estimates were qualitatively similar to the clinic results: -3.0 ppFEV1/year (95% CI: -4.1, -1.9). CONCLUSIONS: To leverage the potential cost, feasibility and convenience of home spirometry, the differences with clinic spirometry must be acknowledged. Significantly lower ppFEV1 in home devices shows that direct comparison to clinic spirometers may induce a spurious change from baseline, and additional variability in home devices impacts statistical power. The effect of coaching, setting, and equipment must be understood to use and improve home spirometry in CF.

Causal Relationship Between Lung Function and Atrial Fibrillation: A Two Sample Univariable and Multivariable, Bidirectional Mendelian Randomization Study.

Background: Observational studies have identified impaired lung function accessed by forced expiratory volume in one second (FEV1), forced vital capacity (FVC) or the ratio of FEV1 over FVC (FEV1/FVC) as an independent risk factor for atrial fibrillation (AF). However, the result may be affected by confounders or reverse causality. Methods: We performed univariable MR (uvMR), multivariable MR (mvMR) and bidirectional two-sample MR to jointly estimate the causality of lung function with AF. Apart from the inverse variance weighted (IVW) approach as the main MR analysis, three complementary sensitive analyses approaches including MR-Egger regression, weighted median (WM) MR and Pleiotropy Residual Sum and Outlier (MR-PRESSO) in uvMR as well as mvMR-Egger and mvMR-PRESSO in mvMR were applied to control for pleiotropy. Linkage disequilibrium score (LDSC) regression was applied to estimate genetic correlation between lung function and AF. Results: All forward and reverse uvMR analyses consistently suggested absent causal relations between lung function and AF risk [forward IVW: odds ratio (OR)FEV1 = 1.031, 95% CI = 0.909-1.169, P = 0.630; ORFVC = 1.002, 95% CI = 0.834-1.204, P = 0.982; ORFEV1/FVC = 1.076, 95% CI = 0.966-1.199, P = 0.182; reverse IVW: ORFEV1 = 0.986, 95% CI = 0.966-1.007, P = 0.187; ORFVC = 0.985, 95% CI = 0.965-1.006, P = 0.158; ORFEV1/FVC = 0.994, 95% CI = 0.973-1.015, P = 0.545]. The forward MR-Egger showed that each standard deviation (SD) increase in FEV1/FVC was related to a higher AF risk (OR = 1.502, 95% CI = 1.178-1.915, P = 0.006) without heterogeneity (Q_pval = 0.064), but pleiotropy effect exist (intercept = -0.017, P = 0.012). However, this significant effect disappeared after adjustment of FEV1 and FVC (OR = 1.523, 95% CI = 0.445-5.217, P = 0.503) in mvMR. No evidence was found for independent causal effects of FEV1 and FVC on AF in mvMR analysis by using mvIVW method (ORFEV1 = 0.501, 95% CI = 0.056-4.457, P = 0.496; ORFVC = 1.969, 95% CI = 0.288-13.474, P = 0.490). Notably, the association between lung function and AF were replicated using the FinnGen cohort data. Conclusions: Our findings reported no coheritability between lung function and AF, and failed to find substantial causal relation between decreased lung function and risk of AF. However, lung function and AF were both associated with inflammation, which may be potential pathway, warranting further study.

Sublobar resection: functional evaluation and pathophysiological considerations.

To date, pulmonary function tests (PFTs) are part of consolidated standard operating procedures in thoracic surgery. PFTs are usually used to assess the pre-operative risk, post-operative outcomes and complications after pulmonary resections. The only functional parameter used in common practice is the forced expiratory volume in one second (FEV1). However, the FEV1 alone poorly reflects lung pathophysiology, especially in patients with pre-operative emphysema and airflow obstruction; moreover, the predictive power of spirometric parameters in guiding the surgical approach in terms of the extension of the excision is currently unknown. In the present critical overview, we report and discuss the results of four studies that compared pre and post-surgery FEV1 and forced vital capacity (FVC) in patients undergoing lobectomy or segmentectomy, highlighting the critical aspects of spirometry in lung surgery and suggesting new approaches for the interpretation of pulmonary mechanics in patients undergoing major or minor parenchymal resections. Overall, the literature on the topic is limited to spirometric parameters, and post-surgical function loss and the consequent recovery are often analysed in inhomogeneous study samples, with varying respiratory comorbidities and functional phenotypes. We underline the role of static lung volumes in the patients' initial assessment. In fact, they tend to decrease in patients with emphysema that undergo a lobectomy, followed by a decrease in lung compliance; some of these patients experience also an increase in closing volume, a condition that worsens the stresses implicated in lung ventilation and promotes the damage to the remaining airways. Spirometric data should be therefore always associated to body-plethysmography and indexes of ventilation distribution, to improve the evaluation of the functional characteristics in patients undergoing lung surgery. Prospective studies are needed to establish the relationship and long-term consequences of different surgical approaches in terms of lung mechanics and functional loss.

Relationship between pulmonary function and brachial-ankle pulse wave velocity in coal miners in northern China.

BACKGROUND: To investigate the relationship between pulmonary function and brachial-ankle pulse wave velocity (baPWV). METHODS: A cross-sectional study was conducted. A total of 11,388 people with complete pulmonary function test and baPWV data and who participated in both the health examination of the Kailuan Occupational Disease Prevention and Treatment Center in 2014-2016 and the health checkup of the Kailuan Group in 2012 and 2014 were selected as subjects. The study population was divided into four groups by forced vital capacity (FVC) quartiles (group 1: FVC <3.50 L; group 2: 3.50 L ≤ FVC <3.96 L; group 3: 3.96 L ≤ FVC <4.47 L; group 4: FVC ≥4.47 L) and divided into four groups by forced expiratory volume in one second (FEV1) quartile (group 1: FEV1 <3.15 L; group 2: 3.15 L ≤ FVC <3.61 L; group 3: 3.61 L ≤ FVC <4.08 L; group 4: FVC ≥4.08 L). Linear regression analysis and multivariate logistic regression were used to analyze the effects of pulmonary function on baPWV. RESULTS: When grouped by FVC, the baPWV of the first group was significantly higher than the other groups. Similarly, the incidence of arteriosclerosis in the first group was significantly higher than the other groups. When grouped by FEV1, the baPWV of the first group was significantly higher than the other groups. The incidence of arteriosclerosis was also significantly higher in the first group than the other groups. After correcting for other confounding factors using linear regression, it was found that the effects of FVC and FEV1 on the study subject's baPWV were -23.84 and -24.65 L, respectively. Multivariate logistic regression analysis showed that when grouped by FVC quartile, the risk of arteriosclerosis was increased by 34% in group 1 compared with group 4 (OR: 1.34, 95% CI: 1.17-1.52); the risk of arteriosclerosis was increased by 16% in group 2 compared with group 4 (OR: 1.16, 95% CI: 1.03-1.31). When grouped by the FEV1 quartile, the risk of arteriosclerosis was increased by 25% in group 1 compared with group 4 (OR: 1.25, 95% CI: 1.10-1.42). CONCLUSIONS: Decreased pulmonary function is negatively correlated with baPWV and is an independent risk factor for arteriosclerosis.

Correlation of severity of chronic obstructive pulmonary disease with serum vitamin-D level.

CONTEXT: The global scenario of illness is shifting from infectious diseases to non-communicable diseases, with chronic conditions such as heart diseases, stroke and Chronic Obstructive Pulmonary Disease (COPD) now being chief causes of death globally and more than 90% of deaths due to COPD occur in low and midline income countries.[1] Low serum vitamin D level is associated with various lung diseases and decreased lung function.[2]. AIMS: This study was designed to study the serum vitamin D level and its correlation with severity of COPD as assessed by spirometry, COPD assessment test (CAT) and exercise capacity and BMI of COPD patients. SETTINGS AND DESIGN: Observational cross sectional study conducted on patients of COPD attending the outpatient department. MATERIALS AND METHODS: One hundred sixty consecutive patients of COPD attending the outpatient Department were included in the study. Pack years, CAT score, 6 minute walk distance, post bronchodilator spirometry values and BMI was recorded along with complete history and physical examination. STATISTICAL ANALYSIS USED: Data analysis was done using IBM SPSS 23 software. Descriptive statistics, Independent sample t test, ANOVA and Pearson correlation were applied. RESULTS: A significant positive correlation was found between FeV1% of predicted and serum Vitamin D level(r = 0.291; P < 0.001). A negative correlation was found between serum Vitamin D level and severity of COPD as assessed by CAT score (r = -0.355; P < 0.001). Also, a significant positive correlation was found between vitamin D levels and exercise capacity as assessed by 6 minute walk test (6MsWT) (r = 0.648; P < 0.001). CONCLUSIONS: COPD patients with more severe disease tend to have lower serum Vitamin D levels. As it is an immunomodulator affecting various inflammatory pathways, it is imperative that we give due consideration to Vitamin D levels in managing patients of COPD.

Anthropometric Indicators Associated with Dyspnea and Spirometric Parameters in Patients with Chronic Obstructive Pulmonary Disease.

BACKGROUND: This study aimed to determine anthropometric indicators associated with dyspnea and spirometric parameters in patients with chronic obstructive pulmonary disease (COPD). MATERIALS AND METHODS: A cross-sectional and observational study was carried out on 88 patients with COPD, who were visited in an outpatient respiratory clinic of a university hospital during two months. Patient height, weight, body mass index (BMI), waist circumference (WC), mid-upper arm circumference (MUAC), triceps skinfold thickness (TSFT) and subscapular skinfold thickness (SST) were recorded. Also, data on lung function and dyspnea were collected. The association between anthropometric indices and other parameters was studied. RESULTS: Pearson's correlation coefficient showed that forced expiratory volume in one second (FEV1)% predicted was positively correlated with BMI (R=0.239, P<0.05) and MUAC (R=0.431, P<0.01). By applying ANOVA, we found that the relationship between FEV1% predicted and BMI (P=0.007), WC (P=0.019) and MUAC (P<0.001) was statistically significant. Chi-square test showed that there was an association between MUAC and dyspnea (P<0.05). CONCLUSION: There was a relationship between FEV1% predicted and some anthropometric indices such as BMI, MUAC and WC; also, we found an association between MUAC and dyspnea.

Associations of interleukin-1 gene cluster polymorphisms with C-reactive protein concentration and lung function decline in smoking-induced chronic obstructive pulmonary disease.

OBJECTIVE: We reported association of haplotypes formed by IL-1b (IL1B)-511C/T (rs16944) and a variable number of tandem repeats (rs2234663) in intron 3 of IL-1 receptor antagonist (IL1RN) with rate of lung function decline in smoking-induced COPD. The aim of current study was to further investigate this association. METHODS: We genotyped an additional 19 polymorphisms in IL1 cluster (including IL1A, IL1B and IL1RN) in non-Hispanic whites who had the fastest (n = 268) and the slowest (n = 292) decline of FEV1% predicted in the same study. We also analyzed the association of all 21 polymorphisms with serum CRP levels. RESULTS: None of 21 polymorphisms showed significant association with rate of decline of lung function or CRP levels after adjusting for multiple comparisons. Before adjusting for multiple comparisons, only IL1RN_19327 (rs315949) showed significant association with lung function decline (P = 0.03, additive model). The frequencies of genotypes containing the IL1RN_19327A allele were 71.9% and 62.2%, respectively in the fast and slow decline groups (P = 0.02, odds ratio = 1.6, 95% confidence interval = 1.1-2.3); the IL1B_5200 (rs1143633) and rs2234663 in IL1RN were associated with serum CRP levels (P=0.04 and 0.03, respectively). CONCLUSIONS: No single marker was significantly associated with either rate of lung function decline or serum CRP levels.

What is the difference between FEV1 change in percentage predicted value and change over baseline in the assessment of bronchodilator responsiveness in patients with COPD?

BACKGROUND: Several criteria are clinically applied in the assessment of significant bronchodilator responsiveness in chronic obstructive pulmonary disease (COPD). The present study aimed to investigate the differences in various degree of severity of COPD among these criteria. METHODS: After 400 micrograms of salbutamol administered via spacer by metered dose inhaler (MDI), forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) changes (including percentage change, absolute change and absolute change in percentage predicted value) were retrospectively analysed in 933 stable patients with mild-to-very-severe COPD. Significant bronchodilator responsiveness was assessed using American Thoracic Society and European Respiratory Society (ATS-ERS) criterion based on FEV1 or/and FVC (both ≥12% increase over baseline and ≥200 mL) and FEV1 percentage predicted criterion (≥10% absolute increase in percentage predicted FEV1) in different grades of COPD. RESULTS: Of the patients [age 66.8 years, baseline FEV1 974 mL (39.3% predicted) and FVC 2,242 mL], mean improvements were 126 mL in FEV1 and 265 mL in FVC; 21.4% and 45.3% met ATS-ERS criterion based on FEV1 and FVC, respectively; and 13.5% met FEV1 percentage predicted criterion. The responsive ratios of ATS-ERS criterion based on FEV1 to FEV1 percentage predicted criterion in grade I, II, III and IV of COPD were 0.95(:)1.26(:)2.53(:)6.00, respectively (P<0.01 in grade II and P<0.001 in grade III). As the degree of severity increased, the mean improvement of FEV1 was reduced; on the contrary, that of FVC was increased. CONCLUSIONS: Compared with FEV1 percentage predicted criterion, ATS-ERS criterion based on FEV1 as well as FVC, the later in particular, detected a larger percentage of patients with significant responsiveness. The increasing difference was relevant as a function of the severity of airflow obstruction.