This study aimed to evaluate discordance, binary classification, and model fit between race-predicted and race-neutral spirometry prediction equations. Spirometry data from 9506 patients (18-95 years old) self-identifying as White, Black, or Hispanic were analyzed, focusing on the lower limit of normal (LLN). Best-fit prediction equations were developed from 3771 patients with normal spirometry, using Bayesian Information Criterion (BIC) to compare models with and without race as a covariate. Results showed that including race as a covariate improved model fit, reducing BIC by at least ten units compared to Race-Neutral equations. Discordance between race-specific and race-neutral equations for detecting airway obstruction and restrictive spirometry patterns ranged from 4% to 13%. Using race-neutral equations resulted in false discovery rates (FDR) of 14% for Hispanics and 45% for Blacks and false negative rates (FNR) of 21% for Hispanics and 27% for Blacks in diagnosing airway obstruction. These findings indicate that removing race as a covariate in spirometry equations increases FDR and FNR, leading to higher misclassification rates. The 4%-13% discordance in interpreting airway obstruction and restrictive patterns has significant clinical implications, underscoring the need for careful consideration in developing spirometry reference equations.
190Implications of adopting the Global Lungs Initiative 2012 all-age reference equations for spirometry
Implications of adopting the Global Lungs Initiative 2012 all-age reference equations for spirometry
4Impacts of Different Spirometry Reference Equations and Diagnostic Criteria on the Frequency of Airway Obstruction in Adult People of North China.
Background and ObjectiveThe reference equations and diagnostic criteria play a critical role in the interpretation of pulmonary function tests (PFTs). The aim was to investigate the impacts of different reference equations and diagnostic criteria on the frequency of airway obstruction in adult people of a large teaching hospital of North China.MethodsThe spirometry data of all adult people who underwent PFTs in Qilu hospital from April 2012 to November 2015 were collected. Two spirometry reference equations, namely, Zhongshan-2011 and Global Lung Function Initiative 2012 (GLI-2012) were compared. The frequency of airway obstruction using different spirometry prediction equations and diagnostic criteria including forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) <92% of predicted value and FEV1/FVC <lower limits of normal (LLN) were investigated.ResultsA total of 57,888 subjects were recruited with a mean age of 55.5 ± 13.72. There were significant differences in LLN and predicted value between the GLI-2012 and Zhongshan-2011. The average age of those who had an LLN of FEV1/FVC below 0.7 was 66.59 ± 6.05 years using GLI-2012, which was significantly lower than that in Zhongshan-2011 (77.46±2.63, P<0.001). Using FEV1/FVC<LLN as diagnostic criteria, Zhongshan-2011 identifies more obstructive subjects than GLI-2012 in each age group. In 45–59 or 60–80 age group, more participants were defined as obstructive using FEV1/FVC<92%pred than FEV1/FVC<LLN (both P<0.001).ConclusionZhongshan-2011 identifies more airway obstruction than GLI-2012 in adult people of North China. Compared to FEV1/FVC<LLN, FEV1/FVC<92%pred may lead to overdiagnosis of airway obstruction in elderly people.
Read moreSymptoms and comorbidities associated with restrictive spirometry
Symptoms and comorbidities associated with restrictive spirometry
OP04 Airway Obstruction and All-Cause and Respiratory Mortality: Exploring the Relationship between three Definitions of Obstruction, Smoking using Healths Survey for England and Scottish Health Survey Data
BackgroundDebate continues about the predictive value of different spirometry based definitions of chronic obstructive pulmonary disease (COPD). We explored the hazard of death for three overlapping definitions, and any significant...
Read more1Household air pollution and airway obstruction in adult female cooks of rural Nepal: A comparative study among biogas and firewood users
Household air pollution and airway obstruction in adult female cooks of rural Nepal: A comparative study among biogas and firewood users
Read moreThe effectiveness of lower limit of normal criteria and cutoff rate of forced expiratory volume in 1 s/forced expiratory volume in 6 s using in the diagnosis of airway obstruction in chronic obstructive pulmonary disease patients diagnosed with fixed ratio
AIMS: The definition of limited airflow as forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) ratio for chronic obstructive pulmonary disease (COPD) is still controversial. The objective of this study was to compare the prevalence of COPD using fixed ratio and lower limit of normal (LLN) of FEV1/FVC for the presence of airflow limitation and evaluate the performance of FEV1/forced expiratory volume in 6 s (FEV6) in patients diagnosed with COPD according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) fixed ratio.\nSUBJECTS AND METHODS: Patients who presented to the pulmonary disease clinic between May 2008 and December 2017 and who were diagnosed with COPD were evaluated retrospectively. The distribution of FEV1/FVC-LLN according to the GOLD fixed ratio was evaluated after the patients were divided based on age groups. A receiver operating characteristics curve was used to determine the best FEV1/FEV6 cutoff value which fit into the FEV1/FVC <LLN, and sensitivity and specificity were calculated.\nRESULTS: Of the patients, 165 (85.9%) were male and 27 were female, with a mean age of 64.40 ± 10.66 years (range, 40–85). Among the patients, 11.5% of 61 patients aged 40–60 years, 28.4% of 67 patients aged 61–70 years, and 26.6% of 64 patients aged over 70 years were out of the diagnosis of obstruction according to the fixed ratio of FEV1/FVC >LLN. The cutoff value of FEV1/FEV6 for airway obstruction according to FEV1/FVC <LLN was 0.735 with a sensitivity of 99.3%, a specificity of 95.3%, and area under the curve of 0.900 (95% confidence interval: 0.856–0.944, P < 0.001).\nCONCLUSIONS: In this study, older patients, particularly, were diagnosed less often with an FEV1/FVC <LLN value calculated according to the Global lung function initiative (GLI) norms, compared to the fixed ratio. In addition, ratio of FEV1/FEV6 of < 0.735 may be useful in the diagnosis of airway obstruction in the early period and may also be used in office-type spirometers, since it is not dependent on a time constant.
Read moreHow frequent are unusual types of ventilatory impairment (mixed and nonspecific)? Analysis of over 10,000 patients data
How frequent are unusual types of ventilatory impairment (mixed and nonspecific)? Analysis of over 10,000 patients data
5Spirometry for the diagnosis of airway obstruction in patients with risk factors for COPD: the GOLD and lower limit of normal criteria.
ABSTRACTObjective:The identification of persistent airway obstruction is key to making a diagnosis of COPD. The GOLD guidelines suggest a fixed criterion-a post-bronchodilator FEV1/FVC ratio < 70%-to define obstruction, although other guidelines suggest that a post-bronchodilator FEV1/FVC ratio < the lower limit of normal (LLN) is the most accurate criterion. Methods:This was an observational study of individuals ≥ 40 years of age with risk factors for COPD who were referred to our pulmonary function laboratory for spirometry. Respiratory symptoms were also recorded. We calculated the prevalence of airway obstruction and of no airway obstruction, according to the GOLD criterion (GOLD+ and GOLD−, respectively) and according to the LLN criterion (LLN+ and LLN−, respectively). We also evaluated the level of agreement between the two criteria. Results:A total of 241 individuals were included. Airway obstruction was identified according to the GOLD criterion in 42 individuals (17.4%) and according to the LLN criterion in 23 (9.5%). The overall level of agreement between the two criteria was good (k = 0.67; 95% CI: 0.52-0.81), although it was lower among the individuals ≥ 70 years of age (k = 0.42; 95% CI: 0.12-0.72). The proportion of obese individuals was lower in the GOLD+/LLN+ category than in the GOLD+/LLN− category (p = 0.03), as was the median DLCO (p = 0.04). Conclusions:The use of the GOLD criterion appears to be associated with a higher prevalence of COPD. The agreement between the GOLD and LLN criteria also appears to be good, albeit weaker in older individuals. The use of different criteria to define airway obstruction seems to identify individuals with different characteristics. It is essential to understand the clinical meaning of discordance between such criteria. Until more data are available, we recommend a holistic, individualized approach to, as well as close follow-up of, patients with discordant results for airway obstruction.
Read more1Air pollution and its effects on lung health in never-smoker youth of Delhi NCR versus Pauri Garhwal: a comparative cross-sectional study
Air pollution and its effects on lung health in never-smoker youth of Delhi NCR versus Pauri Garhwal: a comparative cross-sectional study
Read moreSpirometry Assessments in Children With Sickle Cell Disease in Ghana.
Spirometry Assessments in Children With Sickle Cell Disease in Ghana.
Study of some Pulmonary Function Tests in Children with Sickle Cell Anemia: Correlation with Iron Overload
Background: Sickle cell disease is hereditary hemoglobinopathy characterized by abnormal hemoglobin production, hemolytic anemia, and intermittent occlusion of small vessels, leading to acute and chronic tissue ischemia, and organ damage.Pulmonary function tests can differentiate between obstructive or restrictive lung diseases, assess the severity of the disease and evaluate the degree of efficacy of therapy in patients with sickle cell anemia.Objective: The aim of this study was to study pulmonary function tests in children with sickle cell anemia and its correlation with iron overload. Patients and methods: This study was carried out on 40 children with sickle cell anemia under follow up atHematology unit, Pediatric Department, Tanta university hospital in the period between October 2012 and August 2014 including 24 males and 16 females with their age ranging from 9-15 years and mean age value of 12.7+2.2years and 40 healthy children as a control group including 22 males and 18 females with their age ranging from 7 -15 years and mean age value of 10.3+2.36 years.All patients were subjected to the following investigations: Complete blood count, HB electrophoresis, serum ferritin, serum iron, total iron binding capacity and pulmonary function tests.Results: There were significantly higher serum ferritin, serum iron and lower TIBC in patients than controls, significantly lower Forced vital capacity (FVC), Forced expiratory volume in one second (FEV1), FEV1/FVC ratio, Peak expiratory flow rate, and Forced expiratory Flow in patients compared with controls, significant negative correlation between serum ferritin and both of FVC and FEV1 in studied patients.There were restrictive spirometric pattern in 30 patients with sickle cell anemia (75%) and mixed obstructive and restrictive pattern in 10 patients (25%) with highly significant differences between patients and controls regarding restrictive and mixed pattern of spirometry. Conclusion: Most SCD patients show abnormal pulmonary functions, predominantly of restrictive pattern.Recommendations: Patients with SCD should undergo pulmonary function tests to detect and confirm lung disease for early and proper therapeutic intervention.
Read more25Diagnosis of Airway Obstruction or Restrictive Spirometric Patterns by Multiclass Support Vector Machines
This paper presents the use of multiclass support vector machines (SVMs) for diagnosis of spirometric patterns (normal, restrictive, obstructive). The SVM decisions were fused using the error correcting output codes (ECOC). The multiclass SVM with the ECOC was trained on three spirometric parameters (forced expiratory volume in 1s--FEV1, forced vital capacity--FVC and FEV1/FVC ratio). The total classification accuracy of the SVM is 97.32%. The obtained results confirmed the validity of the SVMs to help in clinical decision-making.
Read moreDecision letter: A method for low-coverage single-gamete sequence analysis demonstrates adherence to Mendel’s first law across a large sample of human sperm
Many species on Earth can carry up to two different versions of a given gene, with each of these ‘alleles’ having only a 50/50 chance of being transmitted to the next generation via sexual reproduction. Certain ‘selfish’ sequences, however, can hijack this process and increase their probability of being passed on to an offspring. Known as transmission distortion, this phenomenon may result in alleles spreading through the population even if they are detrimental to fertility. Transmission distortion has been detected in many species such as flies, mice and some plants. It can take place at various stages during reproduction; for example, the selfish alleles may become overrepresented among eggs or sperm. However, scientists need to study a large number of offspring or reproductive cells to be able to detect whether an allele is inherited more often than expected. This has made it difficult to determine whether transmission distortion also happens in humans, and research so far has resulted in conflicting conclusions. A recently published dataset of human sperm from 25 donors offered Carioscia, Weaver et al. the opportunity to examine this question. Every volunteer had produced between 969 and 3377 sperm cells, each with about 1% of their genome sequenced. Carioscia, Weaver et al. developed a computational method, which they named rhapsodi, that allowed them to ‘fill in the gaps’ and infer missing regions of the genome for each cell. To do so, they relied on the fact that sperm cells from a given individual are highly related to one another. With this more complete data at hand, it became possible to look for evidence of transmission distortion by searching for alleles that were overrepresented in sperm from a given donor. No selfish sequence could be detected in any of the 25 individuals, suggesting that human sperm may not be subject to pervasive transmission distortion. Signatures of selfish alleles detected in previous human studies may have therefore not resulted from this mechanism taking place at the sperm level. Instead, transmission distortion in humans could primarily target eggs or happen at later stages (for instance, if embryos carrying the selfish allele have better chances of survival). The ‘rhapsodi’ method developed by Carioscia, Weaver et al. should allow other scientists to work with datasets for which large portions of the genetic information is missing. It may therefore become easier for researchers to track selfish alleles which are difficult to detect, and to examine bigger, more diverse samples which also include individuals with known fertility challenges.
Read morePerinatal risk factors and lung function at 8years of age in extremely preterm infants: Insights from a new Japanese bronchopulmonary dysplasia classification.
Advances in neonatal care have considerably improved the survival rates of extremely preterm infants. However, long-term pulmonary sequelae remain a major concern. A revised classification of bronchopulmonary dysplasia (BPD) in Japan highlights histological chorioamnionitis, small for gestational age (SGA), and a bubbly/cystic appearance on chest X-ray (bubbly/cystic CXR) as key risk factors. This study aimed to evaluate the effect of extremely preterm birth on lung function at school age. This retrospective study included 283 extremely preterm infants (born at <28 weeks of gestation) admitted to our institution between 1994 and 2013. Perinatal data and spirometry results obtained at 8 years of age were analyzed. Logistic regression analysis was performed to assess the association of histological chorioamnionitis, SGA, and bubbly/cystic CXR with obstructive (FEV1 [forced expiratory volume in 1s]/FVC [forced vital capacity]<LLN [lower limit of normal]), restrictive (FEV1/FVC≥LLN and FVC<LLN), and mixed (FEV1/FVC<LLN and FVC<LLN) patterns, with adjustments for gestational age, sex, and birth year. Extremely preterm infants exhibited lower z-scores for FEV1/FVC, FEV1, and FVC than the predicted values based on age, height, and sex. Bubbly/cystic CXR findings was associated with an increased risk of obstructive (adjusted odds ratio [aOR], 2.30; 95 % confidence interval [CI], 1.12-4.72) and mixed patterns (aOR, 3.51; 95 % CI, 1.19-10.4). SGA was a risk factor for a restrictive pattern (aOR, 2.81; 95 % CI, 1.37-5.74). Bubbly/cystic CXR findings and SGA status, key components of the revised Japanese BPD classification, were significantly associated with long-term pulmonary function abnormalities in extremely preterm infants, characterized predominantly by obstructive/mixed and restrictive patterns, respectively. These findings highlight the importance of targeted strategies to address specific perinatal risk factors and improve long-term pulmonary outcomes in this high-risk population.
Read more5Occupational exposures and small airway obstruction in the UK Biobank Cohort.
Small airways obstruction (SAO) is a key feature of both COPD and asthma, which have been associated with workplace exposures. Whether SAO, which may occur early in the development of obstructive lung disease and without symptoms, also associates with occupational exposures is unknown. Using UK Biobank data, we derived measurements of SAO from the 65 145 participants with high-quality spirometry and lifetime occupational histories. The ALOHA+ Job Exposure Matrix was used to assign lifetime occupational exposures to each participant. The association between SAO and lifetime occupational exposures was evaluated using a logistic regression model adjusted for potential confounders. A second logistic regression model was also run to account for potential co-exposures. SAO was present in varying proportions of the population depending on definition used: 5.6% (forced expiratory flow between 25 and 75% of the forced vital capacity (FEF25-75) < lower limit of normal (LLN)) and 21.4% (forced expiratory volume in 3 s (FEV3)/forced expiratory volume in 6 s (FEV6) <LLN). After adjustment for confounders and co-exposures, people in the highest category of exposure to pesticides were significantly more likely to have SAO (FEV3/FEV6 <LLN: OR 1.24, 95% CI 1.06-1.44). The association between pesticides and SAO showed an exposure-response pattern. SAO was also less likely among people in the highest exposure categories of aromatic solvents (FEV3/FEV6 <LLN: OR 0.85, 95% CI 0.73-0.99) and metals (FEV3/FEV6 <LLN: OR 0.77, 95% CI 0.62-0.94). Our findings suggest that occupational exposure to pesticides play a role in the SAO. However, further work is needed to determine causality, and identify the specific component(s) responsible and the underlying mechanisms involved.
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