Dataset Information

Predicted values for the forced expiratory flow adjusted for forced vital capacity, a descriptive study.

ABSTRACT:

Background

The forced expiratory flows (FEFs) towards the end of the expiration may be more sensitive in detecting peripheral airways obstruction compared to the forced expiratory volume in 1?s and forced vital capacity (FVC). However, they are highly variable. A partial solution is to adjust the FEFs for FVC (FEF/FVC). Here we provide reference equations for these adjusted FEFs at 25%, 50%, 75% and 25-75% of FVC, which are currently lacking.

Methods

We included pulmonary healthy, never-smoker adults; 14?472 subjects from Lifelines, a biobank for health research, and 338 subjects from the department's control cohorts (NORM and Fiddle). Reference equations were obtained by linear regression on 80% of the Lifelines dataset and validated on the remaining data. The best model was defined as the one with the highest adjusted R²-value. The difference in variability between adjusted and unadjusted FEFs was evaluated using the coefficient of variation.

Results

For all adjusted FEFs, the best model contained age, height and weight. The adjustment improved the coefficient of variation of the FEF₇₅ from 39% to 36% and from 43% to 40%, respectively, in males and females. The highest percentage of explained variance by the reference equation was obtained for FEF₇₅/FVC, 32%-38% for males, and 41%-46% for females, depending on the validation set.

Conclusion

We developed reference equations for FVC-adjusted FEF values. We demonstrated minimally yet significantly improved variability. Future studies in obstructive airway diseases should demonstrate whether it is worthwhile to use these (predicted) adjusted FEF values.

SUBMITTER: Cox CA

PROVIDER: S-EPMC7737427 | biostudies-literature | 2020 Oct

REPOSITORIES: biostudies-literature

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Publications

Predicted values for the forced expiratory flow adjusted for forced vital capacity, a descriptive study.

Cox Claire A CA Vonk Judith M JM Kerstjens Huib A M HAM van den Berge Maarten M Ten Hacken Nick H T NHT

ERJ open research 20201001 4

<h4>Background</h4>The forced expiratory flows (FEFs) towards the end of the expiration may be more sensitive in detecting peripheral airways obstruction compared to the forced expiratory volume in 1 s and forced vital capacity (FVC). However, they are highly variable. A partial solution is to adjust the FEFs for FVC (FEF/FVC). Here we provide reference equations for these adjusted FEFs at 25%, 50%, 75% and 25-75% of FVC, which are currently lacking.<h4>Methods</h4>We included pulmonary healthy, ...[more]

PMID: 33344626

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Project description:BackgroundThe assumption that the assessment of forced expiratory flow between 25% and 75% of vital capacity (FEF(25-75)) does not provide additional information in asthmatic children with normal FEV(1) percent predicted has not been adequately tested.ObjectiveWe sought to determine whether the measurement of FEF(25-75) percent predicted offers advantages over FEV(1) percent predicted and FEV(1)/forced vital capacity (FVC) percent predicted for the evaluation of childhood asthma.MethodsThis is a secondary analysis of data from the Pediatric Asthma Controller Trial and the Characterizing the Response to a Leukotriene Receptor Antagonist and Inhaled Corticosteroid trials. Pearson correlation coefficients, Pearson partial correlation coefficients, canonical correlations, and receiver operating characteristic (ROC) curves were constructed.ResultsAmong 437 children with normal FEV(1) percent predicted, FEF(25-75) percent predicted, and FEV(1)/FVC percent predicted were (1) positively correlated with log(2) methacholine PC(20), (2) positively correlated with morning and evening peak expiratory flow percent predicted, and (3) negatively correlated with log(10) fraction of exhaled nitric oxide and bronchodilator responsiveness. Pearson partial correlations and canonical correlations indicated that FEF(25-75) percent predicted was better correlated with bronchodilator responsiveness and log(2) methacholine PC(20) than were FEV(1) percent predicted or FEV(1)/FVC percent predicted. In the ROC curve analysis, FEF(25-75) at 65% of predicted value had a 90% sensitivity and a 67% specificity for detecting a 20% increase in FEV(1) after albuterol inhalation.ConclusionFEF(25-75) percent predicted was well correlated with bronchodilator responsiveness in asthmatic children with normal FEV(1). FEF(25-75) percent predicted should be evaluated in clinical studies of asthma in children and might be of use in predicting the presence of clinically relevant reversible airflow obstruction.

Project description:ObjectivesThe aim of this study was to assess the prevalence and determinants of post-tuberculosis chronic respiratory signs, as well as the clinical impact of a low forced expiratory flow between 25% and 75% (FEF25-75%) in a group of individuals previously treated successfully for pulmonary tuberculosis.DesignThis was a cross-sectional study involving individuals in their post-tuberculosis treatment period. They all underwent a spirometry following the 2005 criteria of the American Thoracic Society/European Respiratory Society. Distal airflow obstruction (DAO) was defined by an FEF25-75% <65% and a ratio forced expiratory volume during the first second (FEV1)/forced vital capacity (FVC) ? 0.70. Logistic regression models were used to investigate the determinants of persisting respiratory symptoms following antituberculous treatment.SettingThis study was carried out in the tuberculosis diagnosis and treatment centre at Yaounde Jamot Hospital, which serves as a referral centre for tuberculosis and respiratory diseases for the capital city of Cameroon (Yaounde) and surrounding areas.ParticipantsAll consecutive patients in their post-tuberculosis treatment period were consecutively enrolled between November 2012 and April 2013.ResultsOf the 177 patients included, 101 (57.1%) were men, whose median age (25th-75th centiles) was 32 (24-45.5) years. At least one chronic respiratory sign was present in 110 (62.1%) participants and DAO was found in 67 (62.9%). Independent determinants of persisting respiratory signs were the duration of symptoms prior to tuberculosis diagnosis higher than 12?weeks (adjusted OR 2.91; 95% CI 1.12 to 7.60, p=0.029) and presence of DAO (2.22; 1.13 to 4.38, p=0.021).ConclusionsFEF25-75%<65% is useful for the assessment and diagnosis of post-tuberculous DAO. Mass education targeting early diagnosis of pulmonary tuberculosis can potentially reduce the prevalence of post-tuberculosis respiratory signs and distal airflow obstruction.

Project description:Rationale: The American Thoracic Society (ATS)/European Respiratory Society defines a positive bronchodilator response (BDR) by a composite of BDR in either forced expiratory volume in 1 second (FEV1) and/or forced vital capacity (FVC) greater than or equal to 12% and 200 ml (ATS-BDR). We hypothesized that ATS-BDR components would be differentially associated with important chronic obstructive pulmonary disease (COPD) outcomes. Objectives: To examine whether ATS-BDR components are differentially associated with clinical, functional, and radiographic features in COPD. Methods: We included subjects with COPD enrolled in the COPDGene study. In the main analysis, we excluded subjects with self-reported asthma. We categorized BDR into the following: 1) No-BDR, no BDR in either FEV1 or FVC; 2) FEV1-BDR, BDR in FEV1 but no BDR in FVC; 3) FVC-BDR, BDR in FVC but no BDR in FEV1; and 4) Combined-BDR, BDR in both FEV1 and FVC. We constructed multivariable logistic, linear, zero-inflated negative binomial, and Cox hazards models to examine the association of BDR categories with symptoms, computed tomography findings, change in FEV1 over time, respiratory exacerbations, and mortality. We also created models using the ATS BDR definition (ATS-BDR) as the main independent variable. Results: Of 3,340 COPD subjects included in the analysis, 1,083 (32.43%) had ATS-BDR, 182 (5.45%) had FEV1-BDR, 522 (15.63%) had FVC-BDR, and 379 (11.34%) had Combined-BDR. All BDR categories were associated with FEV1 decline compared with No-BDR. Compared with No-BDR, both ATS-BDR and Combined-BDR were associated with higher functional residual capacity %predicted, greater internal perimeter of 10 mm, and greater 6-minute-walk distance. In contrast to ATS-BDR, Combined-BDR was independently associated with less emphysema (adjusted beta regression coefficient, -1.67; 95% confidence interval [CI], -2.68 to -0.65; P = 0.001), more frequent respiratory exacerbations (incidence rate ratio, 1.25; 95% CI, 1.03-1.50; P = 0.02) and severe exacerbations (incidence rate ratio, 1.34; 95% CI, 1.05-1.71; P = 0.02), and lower mortality (adjusted hazards ratio, 0.76; 95% CI, 0.58-0.99; P = 0.046). Sensitivity analysis that included subjects with self-reported history of asthma showed similar findings. Conclusions: BDR in both FEV1 and FVC indicates a COPD phenotype with asthma-like characteristics, and provides clinically more meaningful information than current definitions of BDR.

Project description:BACKGROUND:Forced Vital Capacity (FVC) is an important predictor of all-cause mortality in the absence of chronic respiratory conditions. Epidemiological evidence highlights the role of early life factors on adult FVC, pointing to environmental exposures and genes affecting lung development as risk factors for low FVC later in life. Although highly heritable, a small number of genes have been found associated with FVC, and we aimed at identifying further genetic variants by focusing on lung development genes. METHODS:Per-allele effects of 24,728 SNPs in 403 genes involved in lung development were tested in 7,749 adults from three studies (NFBC1966, ECRHS, EGEA). The most significant SNP for the top 25 genes was followed-up in 46,103 adults (CHARGE and SpiroMeta consortia) and 5,062 children (ALSPAC). Associations were considered replicated if the replication p-value survived Bonferroni correction (p<0.002; 0.05/25), with a nominal p-value considered as suggestive evidence. For SNPs with evidence of replication, effects on the expression levels of nearby genes in lung tissue were tested in 1,111 lung samples (Lung eQTL consortium), with further functional investigation performed using public epigenomic profiling data (ENCODE). RESULTS:NCOR2-rs12708369 showed strong replication in children (p = 0.0002), with replication unavailable in adults due to low imputation quality. This intronic variant is in a strong transcriptional enhancer element in lung fibroblasts, but its eQTL effects could not be tested due to low imputation quality in the eQTL dataset. SERPINE2-rs6754561 replicated at nominal level in both adults (p = 0.036) and children (p = 0.045), while WNT16-rs2707469 replicated at nominal level only in adults (p = 0.026). The eQTL analyses showed association of WNT16-rs2707469 with expression levels of the nearby gene CPED1. We found no statistically significant eQTL effects for SERPINE2-rs6754561. CONCLUSIONS:We have identified a new gene, NCOR2, in the retinoic acid signalling pathway pointing to a role of vitamin A metabolism in the regulation of FVC. Our findings also support SERPINE2, a COPD gene with weak previous evidence of association with FVC, and suggest WNT16 as a further promising candidate.

Dataset Information

Predicted values for the forced expiratory flow adjusted for forced vital capacity, a descriptive study.

Background

Methods

Results

Conclusion

Publications

Predicted values for the forced expiratory flow adjusted for forced vital capacity, a descriptive study.

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