Global Lung Initiative Equations Research Articles

Race-neutral Equations and Pulmonary Function Test Interpretation in Two Pediatric Cohorts

ObjectivesTo investigate the changes in predicted lung function measurements when using race-neutral equations in children, based upon the new Global Lung Initiative (GLI) reference equations utilizing a race-neutral approach in interpreting spirometry results compared with the 2012 race-specific GLI equations. Study designWe analyzed data from two multicenter prospective cohorts comprised of healthy children and children with history of severe (requiring hospitalization) bronchiolitis. Spirometry testing was done at the 6-year physical exam and 677 tests were analyzed using new GLI Global and 2012 GLI equations. We used multivariable logistic regression, adjusted for age, height, and sex, to examine the association of race with the development of new impairment or increased severity (FEV1 z-score≤-1.645) as per 2022 ATS guidelines. ResultsCompared with the race-specific GLI, the race-neutral equation yielded increases in the median FEV1 and FVC percent predicted in White children but decreases in these two measures in Black children. The prevalence of obstruction increased in White children by 21% and the prevalence of possible restriction increased in Black children by 222%. Compared with White race, Black race was associated with increased prevalence of new impairments (aOR 7.59; 95%CI, 3.00-19.67; p<0.001) and increased severity (aOR 35.40; 95%CI, 4.70-266.40; p=0.001). Results were similar across both cohorts. ConclusionsAs there are no biological justifications for the inclusion of race in spirometry interpretation, use of race-neutral spirometry reference equations led to an increase in both the prevalence and severity of respiratory impairments among Black children.

Impact of Using Global Lung Initiative Race-neutral Equations for Chronic Respiratory Disease in Western India.

The Global Lung Initiative (GLI) race-neutral equations are considered to be race agnostic, using inverse probability weight, and have lower limits of normality (LLN) different from the GLI mixed equations. In this observational study, we analyzed the impact of using GLI equations to interpret spirometry of 1,169 patients with chronic respiratory diseases, including asthma, chronic obstructive pulmonary disease (COPD), COPD suspects, small airway obstruction, posttubercular lung disease, and preserved ratio with impaired spirometry (PRISm) (46% females, average age 46 years). Predicted normal and the LLN using GLI equations were significantly higher than those using Indian equations. The GLI race-neutral equations changed the category in 35.17% of males and 42.64% of females compared to Indian equations. The GLI mixed equations categorized a greater percentage of patients to have a mixed ventilatory pattern compared to the GLI race-neutral equations. There was a significant change in the grading of the severity of COPD using Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages based on the percentage of predicted values of FEV1. Although GLI race-neutral equations have greater concordance with Indian equations than GLI Mixed equations, these substantially overdiagnose abnormal ventilatory patterns on spirometry in adult Indians in western India with chronic respiratory disease. A substantial number of patients with normal or obstructive patterns on spirometry are recategorized to have mixed or restrictive patterns. The use of GLI race-neutral equations increases the severity of airflow limitation in COPD patients. GLI race-neutral predictions for FEV1 result in substantially fewer patients demonstrating postbronchodilator responsiveness (PBDR).

Referential equations for pulmonary diffusing capacity generated from the Japanese population using the Lambda, Mu, or Sigma method and their comparisons with prior referential equations

BackgroundThis study aimed to establish reference equations for single-breath lung carbon monoxide diffusing capacity (DLCO), alveolar volume (VA), and transfer coefficient of the lungs for carbon monoxide (KCO, sometimes written as DLCO/VA) in the Japanese population. A generalised additive model for location size and shape (GAMLSS) was used to build each equation. MethodsTo collect pulmonary function data throughout a broad age range, we prospectively obtained pulmonary function data from healthy volunteers and retrospectively obtained data from patients with normal diffusing capacity aged 16–85 years. ResultsIn total, 702 tests were conducted. The validation group z-scores, except for DLCO in males, showed substantial discrepancies between the Global Lung Initiative (GLI) baseline prediction equations and the present study’s prediction equations, indicating the need for a new reference value prediction approach. The root mean square errors of the DLCO, VA, and KCO reference values obtained from the present study’s prediction equations were lower than those derived from the GLI and previous linear regression equations. ConclusionsReference values obtained in this study were more appropriate for our sample than those derived from the existing baseline prediction equations. This research’s contribution is the development of a more precise prediction equation that can be used to establish a reference value range for pulmonary diffusing capacity. Ethics and disseminationThis research does not include any dissemination plan (publications, data deposition and curation).

Decoupling race/ethnicity from pediatric lung function metrics to investigate potential misclassification bias in environmental epidemiologic research

Background and aim: Electronic health records (EHR) are increasingly being used in environmental epidemiologic research. Respiratory studies of asthma commonly use derived spirometry metrics, such as percent predicted forced expiratory volume in one second (FEV1%predicted), that are calculated from age, height, sex, and – controversially – race/ethnicity. We examine potential misclassification bias introduced by historically race/ethnicity-adjusted pediatric lung function metrics. Methods: Spirometry results for children with asthma ages 5-17 years were obtained from a clinical EHR data repository at Boston Medical Center (BMC) from 2003 to 2019. BMC is New England’s largest safety net hospital, serving a racio-ethnically diverse pediatric population. Recorded lung function metrics included FEV1 (liters), forced vital capacity (liters), and previously calculated FEV1%predicted (%) that adjusted for race/ethnicity. We recalculated FEV1%predicted values by standardizing to a global, multiethnic population using the Global Lung Initiative equations and compared to original FEV1%predicted from the EHR data repository. Results: The EHR included 1141 children that had 2651 spirometry measurements. Mean FEV1%predicted was 91.6% from the EHR and 87.2% when recalculated. Original FEV1%predicted values were higher compared to recalculated values for Black children (mean=89.3% [standard error=0.56] vs. 82.5% [0.42] , n=1526, p&amp;#x3c;0.01), but not for Asian (93.8% [3.72] vs. 92.0% [3.59], n=32, p=0.72), Hispanic (96.5% [1.65] vs. 94.4% [1.56], n=129, p=0.37), Other (93.8% [3.55] vs. 91.3% [2.52], n=47, p=0.57), Not Recorded (94.7% [0.73] vs. 94.1% [0.66], n=720, p=0.25), and White (94.1% [1.72] vs. 94.1% [1.42], n=195, p=0.97). Conclusions: Race/ethnicity-adjustment of a commonly used &amp;#x22;objective” lung function metric in EHR may artificially improve lung function test results, particularly for Black children with asthma, resulting in a potential source of misclassification bias in environmental epidemiologic research. Continued use of historically race/ethnicity-adjusted lung function metrics warrants critical reevaluation, especially in research aimed at disentangling the environmental drivers of health disparities driven by structural racism.

THE PREVALENCE OF SMALL AIRWAYS DYSFUNCTION IN ASTHMATICS WITH AIRFLOW OBSTRUCTION

TYPE: Abstract TOPIC: Allergy and Airway PURPOSE: To evaluate the prevalence and characteristics of small airways dysfunction (SAD) in adult asthmatic patients with persistent airflow obstruction as measured by FEV1/FVC. METHODS: Spirometry records of adult patients diagnosed with asthma were retrospectively obtained from the pulmonary function unit of a tertiary hospital in the West Midlands, United Kingdom. The 2012 Global Lung Initiative equations were used to produce % predicted values and z-scores. Airflow obstruction was defined as a z-score of <-1.645 in FEV1/FVC. The SAD was defined as a z-score of <-1.645 in MMEF. The z-score for FEV1 was used to categorize the severity of the obstruction as per the ARTP guidelines. Demographics were also obtained to assess the characteristics of patients with and without SAD. RESULTS: A total of 395 records were obtained, of which 337 (85.3%) had evidence of SAD as measured by MMEF. Although most patients with mild airflow obstruction had evidence of SAD (63.1%), it was the only severity group with a prevalence of less than 100%. SAD was more prevalent in females (89.53%) than males (81.37%) (p= 0.032). No statistical differences were found between smoking history, age, weight, height, or ethnicity when compared to those with and without SAD. CONCLUSIONS: As measured by MMEF, the prevalence of SAD is high in asthmatic patients with physiological airflow obstruction and is more common in females. CLINICAL IMPLICATIONS: In asthmatic patients with airflow obstruction, therapies that also target small airways should be considered in the treatment plan. DISCLOSURE: Nothing to declare. KEYWORD: Asthma

Spirometric reference equations for Cameroonians aged 4 to 89\xa0years derived using lambda, mu, sigma (LMS) method

BackgroundSpirometric reference values are well known in several ethnic groups but the normative spirometric values of blacks living in Africa have been less studied. The purpose of this study is to establish normative spirometric equations from a representative population of Cameroonian children and adults and compare these equations with those developed by the Global Lung Initiative (GLI) and in Nigerians.MethodsSpirometric data from healthy Cameroonians aged 4–89 years randomly collected between 2014 and 2018 were used to derive reference equations using generalized additive model for location (mu), shape (lambda) and scale (sigma).ResultsA total of 625 children and adolescents (290 males and 335 females) and 1152 adults (552 males and 600 females) were included in the study. The prediction equation for spirometric index was written as: M = Exp[a0 + a1*ln (Height) + a2*ln (Age) + Mspline, Mspline was age related spline contribution]. Applying the GLI standards for African Americans resulted in overall values greater than those found in our study for forced expiratory volume in 1s (FEV1) and forced vital capacity (FVC). These values were very close in children and adolescents while the values obtained with the GLI equations for African Americans were significantly higher in adults. FEV1/FVC ratio in our study was similar for adult males but lower in adult females (88% vs 85%, difference = + 3.5%) when applying Nigerian standards.ConclusionsFEV1 and FVC of the Cameroonian infant and adolescent population are very close to those of black Americans. However, FEV1 and FVC of Cameroonian adults are significantly lower than those of black American adults. These equations should allow a more suitable interpretation of spirometry in the Cameroonian population.

The applicability of the global lung initiative equations and other regional equations on a sample of healthy Middle Eastern adolescents.

The Global Lung Initiative 2012 (GLI-2012) spirometry equations are multi-ethnic equations that cover all ages between 3 and 95. However, there is a need to evaluate the suitability of these equations to a sample of Middle Eastern adolescents prior to being applied in clinical practice. The aim of this study is to evaluate the suitability of GLI-2012 equations and two regional equations to a sample of Jordanian adolescents. Spirometric measures were collected from 1036 healthy 14 to 17-year-old Jordanian children. z-scores, predicted values, percent predicted values, and frequency of measures below lower limit of normal (LLN) were calculated for each adolescent using the studied equations. The means of z-scores produced by GLI-2012 equations for Caucasians in forced expiratory volume in the first second (FEV1), forced vital capacity (FVC), FEV1/FVC% and mid forced expiratory flow (FEF25-75) for boys were 0.12, -0.06, 0.34 and 0.09, respectively, while for girls they were -0.09, -0.16, 0.19 and -0.05, respectively. The mean of z-scores produced by GLI-2012 Other or Mixed equations in FEV1, FVC, FEV1/FVC% and FEF25-75 for boys were 0.74, 072, 021 and 0.33, respectively, and for girls were 0.53, 0.56,0.02 and 0.2, respectively. The frequency of measures below LLN as produced by GLI 2012 for Caucasians were significantly different from the expected 5% in FEV1 and FEF25-75 in boys only, whereas Other or Mixed produced frequencies significantly different from the expected 5% in most of the parameters. Spirometry reference equations formulated for Jordanian adolescents may improve the diagnosis and treatment of asthma in Jordan.

Reference values for spirometry in elderly individuals: a cross-sectional study of different reference equations

Background: Spirometry is the single most important test for the evaluation of respiratory function. The results are interpreted by comparing measured data with predicted values previously obtained from a reference population. Reference equations for spirometry have been discussed previously. The aim of this study was to compare reference values based on National Health and Nutrition Assessment Survey (NHANES III), European Community of Steel and Coal (ECSC), and Global Lung Initiative (GLI) equations in an elderly sample population. Methods: Subjects from the Geriatric Study on Health Effects of Air Quality in elder care centres who met the inclusion criteria were enrolled. Spirometry was performed according to international guidelines. The forced vital capacity, forced expiratory volume in 1 s, and FEV1/FVC ratio were reported as percentages of the predicted value, and the lower limit of normality was calculated. Results: Out of 260 elderly patients, 69.6% were women; the mean age was 83.0 ± 6.46 years with an age range of 65– 95 years. The lowest %FVC and %FEV1 values were obtained using the GLI reference equations. However, when NHANES III equations were used, the FEV1/FVC ratio was higher than ratios obtained from GLI and ECSC equations. The prevalence of airway obstruction was highest using ECSC equations, while GLI equations demonstrated more restrictive defects. Conclusions: The present study showed meaningful differences in the reference values, and consequently, in the results obtained using NHANES III, ECSC, and GLI reference equations. The spirometry interpretation was also influenced by the reference equations used.

Lung health and exposure to air pollution in Malawian children (CAPS): a cross-sectional study

BackgroundNon-communicable lung disease and exposure to air pollution are major problems in sub-Saharan Africa. A high burden of chronic respiratory symptoms, spirometric abnormalities and air pollution exposures has been found...

Lung function: population epidemiology and concordance in Australian children aged 11-12 years and their parents.

ObjectivesTo describe the epidemiology of lung function in Australian children aged 11–12 years and their parents, and explore the degree of intergenerational concordance.DesignCross-sectional study (the Child Health CheckPoint) nested in the Longitudinal Study of Australian Children (LSAC).SettingAssessment centres in seven Australian cities and eight regional towns, February 2015 to March 2016. Families unable to attend a clinic appointment were offered a home visit during the same period.Participants1874 families (53% of all eligible) participated in the study. Lung function data were available for 1759 children aged 11–12 years and 1774 parents (1668 biological pairs).Outcome measuresParticipants completed spirometry with measures including forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and mid expiratory flow (MEF), converted to z-scores using Global Lung Initiative equations. Parent–child concordance was assessed using Pearson’s correlation coefficients and multivariable linear regression models. Survey weights and methods accounted for LSAC’s complex sampling, stratification and clustering within postcodes.ResultsAll lung function measures followed approximately normal distributions. Mean (SD) for FEV1, FVC and MEF z-scores in children were 0.33 (1.07), 0.83 (1.14) and −0.48 (1.09), respectively. Mean (SD) in parents were 0.28 (1.10), 0.85 (1.15) and −0.45 (1.10), respectively. Parent FEV1, FVC and MEF were associated with child lung function with significant positive correlation coefficients (0.22, 95% CI 0.17 to 0.26; 0.24, 95% CI 0.20 to 0.29; and 0.24, 95% CI 0.20 to 0.29, respectively).ConclusionsMean lung volumes were larger but with smaller airway size than international standards for both parents and children in this population sample. Modest associations between parent and child lung function highlight the potential for better identification of ‘at risk’ populations. Therefore, these findings may aid the development of health policy that aims to prevent the onset or limit the progression of lung disease.

Prediction of Post-Tuberculosis Lung Function Impairment

Objective: The aim of this study was to establish prediction equations for post-tuberculosis residual lung function in patients successfully treated for pulmonary tuberculosis (PTB). Methods: This study took place at the Yaounde Jamot Hospital of Yaounde (YJH) and used data from three cross-sectional studies conducted from January to July 2015 (7 months), December 2015 to May 2016 (6 months) and from January to May 2017 (5 months). Adults successful treated for bacteriologically proven pulmonary TB were included. Spirometric indices including forced expiratory volume in 1s (FEV1), forced vital capacity (FVC) and FEV1/FVC ratio were measured using standard methods. Predicted values were estimated using the reference spirometric equations of the Global Lung Initiative equations (GLI) 2012. General linear models were used to establish prediction equations of post-tuberculous residual lung function. Internal validation of the derived models used the bootstrap resampling procedures. A difference was considered significant if p th -75 th percentiles) of men was 40 (31-50) years and that of women was 36(27.8-46) years (p=0.002). Determinants of the post-tuberculosis spirometric indices vary according to each indice and include age, weight, height, body mass index, smoking, duration of symptoms before TB treatment, persistent of respiratory symptoms after TB treatment, persistent of cavity lesions and extension of lung sequelae. The prediction equations of the spirometric indices have been established separately for men and women to account for significant differences in the absolute values of spirometric parameters in men and women. The prediction equations of residual lung function parameters were in the form: lung function parameters = Intercept + β1*P1 + β 2 *P 2 +…βn*P n ; β n is regression coefficient for corresponding predictor (P n ), for categorical variables P n is 1 if the modality is present and 0 if the modality is absent. For each of the spirometric variable, differences in performance measures (optimism) were mostly marginal. Conclusion: The equations developed and validated in this study could help the selection of patients in whom spirometry should be a priority after TB treatment. Like any newly developed model, results from this study are just preliminary findings. Models will require independent external validation to establish the performance both in the study setting and in other settings.

Reference values for the carbon monoxide diffusion (transfer factor) in a brazilian sample of white race.

ABSTRACTObjectiveTo derive reference values from white race adults, for DCO in a sample from different sites in Brazil, through the same equipment model (Sensormedics), and compare the results with the derivatives from Crapo, Miller, Neder equations and from the Global Lung Initiative (GLI) proposal.MethodsThe tests were performed according to the norms suggested by ATS/ERS in 2005 in six Brazilian cities, with 120 adult volunteers of each gender, non-smokers, without referred anemia and without lung or cardio diseases. The expected values were derived from linear regressions and the differences between the values forecasted by some authors and the ones observed in the current study were calculated.ResultsAmong men, the age varied between 25 and 88 years old, and the height varied between 140 and 176 cm. DCO was correlated significantly and positively with the height and negatively with the age. The values forecasted by Crapo, Neder, and Miller equations were higher in comparison with the ones obtained by the current study (p<0.01) in both genders. Among men, the values did not differ when compared to the ones calculated by GLI (p=0.29); among women, the values derived by GLI were slightly higher: 0.99 ml/min/mmHg (p<0.01).Conclusionnew values forecasted for DCO were derived in a sample of white adults in Brazil. The forecasted values are similar to the ones complied by GLI equations and differ from the previously proposed equations.

Reference values for spirometry in elderly individuals: a cross-sectional study of different reference equations

BackgroundSpirometry is the single most important test for the evaluation of respiratory function. The results are interpreted by comparing measured data with predicted values previously obtained from a reference population. Reference equations for spirometry have been discussed previously. The aim of this study was to compare reference values based on National Health and Nutrition Assessment Survey (NHANES III), European Community of Steel and Coal (ECSC), and Global Lung Initiative (GLI) equations in an elderly sample population.MethodsSubjects from the Geriatric Study on Health Effects of Air Quality in elder care centres who met the inclusion criteria were enrolled. Spirometry was performed according to international guidelines. The forced vital capacity, forced expiratory volume in 1 s, and FEV1/FVC ratio were reported as percentages of the predicted value, and the lower limit of normality was calculated.ResultsOut of 260 elderly patients, 69.6% were women; the mean age was 83.0 ± 6.46 years with an age range of 65–95 years. The lowest %FVC and %FEV1 values were obtained using the GLI reference equations. However, when NHANES III equations were used, the FEV1/FVC ratio was higher than ratios obtained from GLI and ECSC equations. The prevalence of airway obstruction was highest using ECSC equations, while GLI equations demonstrated more restrictive defects.ConclusionsThe present study showed meaningful differences in the reference values, and consequently, in the results obtained using NHANES III, ECSC, and GLI reference equations. The spirometry interpretation was also influenced by the reference equations used.

Can the New Global Lung Initiative Equations Better Stratify the Risk of Death in Elderly People with Chronic Obstructive Pulmonary Disease?

Background: The forced expiratory volume in the first second (FEV₁) is commonly expressed as percentage of its value predicted by equations. The most commonly used equations are poorly applicable to elderly people. Recently, a set of equations (Global Lung Initiative, GLI) has been released that is expected to be more appropriate in this population. Objectives: We evaluated the agreement of the GLI, European Respiratory Society (ERS), and National Health and Nutrition Examination Survey (NHANES) equations for prediction of FEV₁ and compared their discriminative capacity with respect to mortality, taking as reference the prediction equation developed in the population from which our sample was drawn (SARA). Methods: We studied 264 patients with chronic obstructive pulmonary disease aged ≥70 years. Agreement was evaluated using the Bland-Altman method, discriminative capacity using incidence rate ratios for mortality calculated across quartiles of each measure. Results: The mean age of the sample was 75.8 years (72.7% men). In women, the mean FEV1ERS/FEV1SARA, FEV1NHANES/ FEV1SARA, and FEV1GLI/FEV1SARA were 0.81, 0.91, and 0.966, respectively. The corresponding values in men were 0.959, 0.963, and 1.02, respectively. The overall discriminative capacity with respect to death was equally poor for all equations. Conclusion: The GLI equations for predicting FEV₁ provide similar estimates compared to an equation developed in a healthy subset of the population in which they are applied, and higher values compared to the ERS equation, especially in women. However, the use of the GLI equation does not improve the stratification of the risk of mortality in elderly people compared to ERS or NHANES equations.

The Prevalence of Chronic Obstructive Pulmonary Disease by the Global Lung Initiative Equations in North-Western Russia

Background: The prevalence of chronic obstructive pulmonary disease (COPD) varies in different countries, while the cut-off for airflow obstruction (AO) is still contested. No COPD prevalence data based on the Global Lung Initiative (GLI) 2012 equations are available in Russia. Objectives: This study aims to assess AO prevalence by the GLI lower limit of normal (GLI-LLN) and the fixed cut-off, to identify AO risk factors and to assess the diagnostic value of respiratory symptoms in north-western Russia. Methods: In a north-western Russian population-based sample of 2,974 adults aged 35-70 years, data on socio-demographics, smoking, occupational exposures and respiratory symptoms were collected, and spirometry was performed before and after bronchodilator (BD) administration. Results: The AO prevalence was 6.8% (95% CI 5.8-7.9) based on the fixed and 4.8% (95% CI 3.9-5.7) based on the GLI-LLN cut-off. 22.5% of the participants with post-BD AO had a positive bronchodilator test, and 1% showed a paradoxical BD response. Of the environmental factors studied, only smoking was independently associated with AO (odds ratio 2.47, 95% CI 1.60-3.82). The positive predictive value of respiratory symptoms for AO was 11% based on the fixed and 8% based on the GLI-LLN cut-off. Conclusions: In a sample of adults in north-western Russia, the AO prevalence by the GLI-LLN cut-off was lower than that by the fixed cut-off. The predictive value of respiratory symptoms was low.

Diminished pulmonary function in long-term workers exposed to cotton dust determined in a cross-sectional study in small Pakistani enterprises

PurposeWhile large cotton industry plants producing for the foreign market have undergone improvements of occupational hygiene lately, working conditions in power looms producing mainly for the local market are still...