The pragmatic role of FEF25-75 in asymptomatic subjects, allergic rhinitis, asthma, and in military setting

Diagnostic Accuracy of FEF25-75 for Bronchial Hyperresponsiveness in Patients with Suspected Asthma and/or Allergic Rhinitis: A Systematic Review and Meta-analysis

BACKGROUND

Some studies have suggested that the forced expiratory flow between 25 and 75% of vital capacity (FEF25-75) can be used as an early marker of bronchial hyperresponsiveness (BHR) in asthma and allergic rhinitis (AR), but is highly variable. Here, we aimed to assess whether the FEF25-75 can be used to diagnose BHR in patients with asthma-like symptoms and AR.

METHODS

PubMed, EMBASE, Web of Science, Wiley Online Library, Cochrane Library, SinoMed, CNKI, and Wanfang Data were searched to acquire eligible studies. Articles published before 30 Sep 2023 were included. Quality Assessment of Diagnostic Accuracy Studies 2 was used to evaluate the risk of bias and application concern of the included articles. Data were pooled using random-effects models. The univariable meta-regression and subgroup analyses were used to explore the sources of heterogeneity.

RESULTS

Twenty-five studies were included, describing 12,310 patients with asthma-like symptoms and AR. In terms of the FEF25-75, the pooled sensitivity and specificity were 0.56(95% CI 0.47-0.65) and 0.86 (95% CI 0.80-0.90), respectively. In addition, the pooled diagnostic odds ratio (DOR) was 8.00 (95% CI 6-10) and the area under the curve (AUC) was 0.80 (95% CI 0.76-0.83). Furthermore, we performed the univariable meta-regression and subgroup analyses, indicating that the disease types and ethnicity may be the sources of heterogeneity.

CONCLUSION

This meta-analysis showed that if BPT cannot be performed a value of FEF25-75 < 65% of predicted may suggest the presence of BHR in patients with suspected asthma and /or AR.

Covert airflow obstruction dominates the overt ones in interstitial lung disease: An appraisal

Background & objectives The co-presence of non-emphysematous airflow obstruction in interstitial Lung disease (ILD) is not elaborated. The present study aims the job with spirometry. Methods ILD affected individuals with or without airflow obstruction (FEV1/FVC<0.7 or >0.7) on spirometry were compared in terms of FEV1 and FEF25-75 derived variables [FEF25-75 (%-predicted), FEV1-FEF25-75 distance, reversibility of FEV1 and FEF25-75 to salbutamol and change in FEV1 and FEF25-75 in %-predicted values]. Those showing significant difference (P=0.0001) suggesting obstruction were selected to draw respective receiver operating curve (ROC) curves to identify the best cut-off value for individual parameters. The efficacy of each surrogate was tested to identify airflow obstruction in both the initial 'overlap' as well as the 'unmixed' ILD affected individual for the presence of airflow obstruction. Results FEV1/FVC identified 30 overlap from 235 ILDs. The FEF25-75 (%-predicted), FEV1-FEF25-75 distance, FEF25-75 reversibility (in ml) and FEV1 (%-predicted) were significantly (P<0.0001) different between the two groups. Of these, the FEF25-75 (%-predicted) had high specificity and sensitivity (93.33 and 79.47%) to identify airflow limitation in the initial unmixed ILD-group. The surrogates with their cut off values identified 92 extra individuals making it 122/235 (51.91%) of ILD having airflow obstruction. The 'unmixed' group showed higher frequency and degree of FEV1 reversibility. Interpretation & conclusions The findings of this study suggest that the airflow obstruction in ILD involves both the intrathoracic large and small airways. Although seemingly parallel, their relative status (qualitative and quantitative) needs research especially in light of the a etio pathology and the extent of involvement of ILD.

Combining small airway parameters with conventional parameters obtained during spirometry to diagnose airflow obstruction: A cross-sectional study

BACKGROUND AND OBJECTIVE

The use of small airway parameters generated by spirometry, namely forced expiratory flow between 25% and 75% of forced vital capacity (FVC) (FEF25%-75%) and forced expiratory flow at 50% and 75% of FVC (FEF50% and FEF75%, respectively), is widely discussed. We evaluated the importance of these spirometric parameters in a large Chinese population.

METHODS

We conducted a cross-sectional observational study in which spirometry and bronchodilator responsiveness (BDR) data were collected in a healthcare centre from May 2021 to August 2022 and in a tertiary hospital from January 2017 to March 2022. Discordance was assessed between the classification of test results by the large airway parameters of forced expiratory volume in 1 second (FEV1) and FEV1/FVC ratio and by the small airway parameters of FEF25%-75%, FEF75% and FEF50%. The predictive power of Z-scores of spirometric parameters for airflow limitation and BDR was assessed using receiver operating characteristic curves.

RESULTS

Our study included 26,658 people. Among people with a normal FVC (n = 14,688), 3.7%, 4.5% and 3.6% of cases exhibited normal FEV1/FVC ratio but impaired FEF25%-75%, FEF75% and FEF50%, respectively, while 6.8%-7.0% of people exhibited normal FEV1 but impaired FEF25%-75%, FEF75% and FEF50%. Using the Z-scores of combining both large and small airway parameters in spirometry showed the best area under the curve for predicting airflow limitation (0.90; 95% CI 0.87-0.94) and predicting BDR (0.72; 95% CI 0.71-0.73).

CONCLUSION

It is important to consider both large and small airway parameters in spirometry to avoid missing a diagnosis of airflow obstruction.

Independent and combined associations of multiple-heavy-metal exposure with lung function: a population-based study in US children

Previous research has found relationships between some single metals and lung function parameters. However, the role of simultaneous multi-metal exposure is poorly understood. The crucial period throughout childhood, when people are most susceptible to environmental dangers, has also been largely ignored. The study aimed to evaluate the joint and individual associations of 12 selected urinary metals with pediatric lung function measures using multi-pollutant approaches. A total of 1227 children aged 6-17 years from the National Health and Nutrition Examination Survey database of the 2007-2012 cycles were used. The metal exposure indicators were 12 urine metals adjusted for urine creatinine, including arsenic (As), barium (Ba), cadmium (Cd), cesium (Cs), cobalt (Co), mercury (Hg), molybdenum (Mo), lead (Pb), antimony (Sb), thallium (Tl), tungsten (Tu), and uranium (Ur). The outcomes of interest were lung function indices, including the 1st second of a forceful exhalation (FEV₁), forced vital capacity (FVC), forced expiratory flow between 25 and 7% of vital capacity (FEF_25-75%), and peak expiratory flow (PEF). Multivariate linear regression, quantile g-computation (QG-C), and Bayesian kernel machine regression models (BKMR) were adopted. A significantly negative overall effect of metal mixtures on FEV₁ (β = - 161.70, 95% CI - 218.12, - 105.27; p < 0.001), FVC (β = - 182.69, 95% CI - 246.33, - 119.06; p < 0.001), FEF_25-75% (β = - 178.86 (95% CI - 274.47, - 83.26; p < 0.001), and PEF (β = - 424.17, 95% CI - 556.55, - 291.80; p < 0.001) was observed. Pb had the largest negative contribution to the negative associations, with posterior inclusion probabilities (PIPs) of 1 for FEV₁, FVC, and FEF_25-75%, and 0.9966 for PEF. And Pb's relationship with lung function metrics showed to be nonlinear, with an approximate "L" shape. Potential interactions between Pb and Cd in lung function decline were observed. Ba was positively associated with lung function metrics. Metal mixtures were negatively associated with pediatric lung function. Pb might be a crucial element. Our findings highlight the need for prioritizing children's environmental health to protect them from later respiratory disorders and to guide future research into the toxic mechanisms of metal-mediated lung function injury in the pediatric population.

Pulmonary function in school-age children following intravitreal injection of bevacizumab for retinopathy of prematurity

The effect of anti-vascular endothelial growth factor on neonatal lung development was inconclusive. To evaluate pulmonary function in school-age children who have received intravitreal bevacizumab (IVB) for retinopathy of prematurity (ROP), this study included 118 school-aged children who were grouped into three groups: full-term control children (group 1), preterm children who had not received IVB treatment (group 2) and preterm children with ROP who had received IVB treatment (group 3). Pulmonary function was measured by spirometry and impulse oscillometry. Pulmonary function was significantly better in group 1 than in groups 2 and 3 (all p < 0.05 in forced vital capacity (FVC), forced expiratory volume in 1 s (FEV₁), forced expiratory flow between 25 and 75% of FVC (FEF_25-75), and respiratory resistance at 5 Hz and difference between respiratory resistance at 5 and 20 Hz (R5-R20). There were no statistically significant differences between group 2 and group 3 in all pulmonary function parameters, including FVC, FEV₁, ratio of FEV₁ to FVC, FEF_25-75, R5, R20, R5-R20, and respiratory reactance at 5 Hz. In conclusion, our study revealed that preterm infants receiving IVB for ROP had comparable pulmonary function at school age to their preterm peers who had not received IVB treatment.

Obesity is a risk factor for decrease in lung function after COVID-19 infection in children with asthma

INTRODUCTION

It is not clear whether asthma, the most frequent chronic disease in childhood, is a risk for severe SARS-CoV-2 infection in the pediatric population and how SARS-CoV-2 infection affects the lung functions in these patients.

PURPOSE

We aimed to investigate the course and the consequences of SARS-CoV-2 infection among children with asthma and determine the risk factors for the decline in lung function tests (LFTs).

METHODS

In this retrospective study, asthmatic children with coronavirus disease 2019 (COVID-19) were compared with a random control group of asthmatic patients without COVID-19. In addition, the clinical course and the effect on LFTs of COVID-19 among children with asthma were also evaluated.

RESULTS

One hundred eighty-nine patients who had COVID-19, and 792 who did not were included in the study. Fever, fatigue, and cough were the most frequent symptoms during COVID-19. Regarding the severity of COVID-19, 163 patients (87.6%) had a mild clinical condition, 13 (7%) had moderate disease, 1 (0.5%) had severe disease, and 2 had (1.1%) critically ill disease. Two patients were diagnosed with multisystem inflammatory syndrome in children (MIS-C), one patient suffered from pneumothorax. LFTs of the patients before and after COVID-19 infection were analyzed; no significant differences were found in FEV1 % (91.7% vs. 90.9%, p = 0.513), FVC% (89.8% vs. 90.8%, p = 0.502) and FEV1 /FVC (103.1% vs. 100.6%, p = 0.056), while FEF25%-75% values (107.6% vs. 98.4%, p < 0.001) were significantly lower after the COVID-19 infection. Obesity (odds ratio [OR]: 3.785, 95% confidence interval [CI]: 1.152-12.429, p = 0.028] and having a family history of atopy (OR: 3.359, 95% CI: 1.168-9.657, p = 0.025] were found to be the independent risk factors for ≥25% decrease in FEF25-75 after COVID-19 infection.

CONCLUSION

COVID-19 infection leads to dysfunction of the small airways in asthmatic children and obesity is an independent risk factor for a ≥25% decrease in FEF25-75. The long-term effects of COVID-19 infection especially on small airways require close monitoring in children with asthma.

Association between Lung Function and New-Onset Diabetes Mellitus in Healthy Individuals after a 6-Year Follow-up

BACKGROUND

We analyzed hemoglobin A1c (HbA1c) levels and various lung function test results in healthy individuals after a 6-year follow-up period to explore the influence of lung function changes on glycemic control.

METHODS

Subjects whose HbA1c levels did not qualify as diabetes mellitus (DM) and who had at least two consecutive lung function tests were selected among the people who visited a health promotion center. Lung function parameters, including forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), FEV/FVC ratio, and forced expiratory flow 25% to 75% (FEF25%-75%), were divided into four groups based on their baseline quantiles. To evaluate future DM onset risk in relation to lung function changes, the correlation between baseline HbA1c levels and changes in lung function parameters after a 6-year follow-up period was analyzed.

RESULTS

Overall, 17,568 individuals were included; 0.9% of the subjects were diagnosed with DM. The individuals included in the quartile with FEV1/FVC ratio values of 78% to 82% had lower risk of DM than those in the quartile with FEV1/FVC ratio values of ≥86% after adjusting for age, sex, and body mass index (P=0.04). Baseline percent predicted FEV1, FVC, FEV1/FVC ratio, and FEF25%-75%, and differences in the FEV1/FVC ratio or FEF25%-75%, showed negative linear correlations with baseline HbA1c levels.

CONCLUSION

Healthy subjects with FEV1/FVC ratio values between 78% and 82% had 40% lower risk for future DM. Smaller differences and lower baseline FEV1/FVC ratio or FEF25%-75% values were associated with higher baseline HbA1c levels. These findings suggest that airflow limitation affects systemic glucose control and that the FEV1/FVC ratio could be one of the factors predicting future DM risk in healthy individuals.

Allergen immunotherapy for house dust mite-induced rhinitis: prescriptive criteria

Allergic rhinitis (AR) is a very common disease. In most cases, therapy is based on symptomatic drugs, while allergen immunotherapy (AIT), which is the only one to act on the cause of the disease, is reserved for patients with a greater burden of disease. In particular, the possible evolution towards asthma substantiates the use of AIT, but requires the availability of diagnostic indices related to the risk of developing asthma. We analyzed the available literature on risk factors for onset of asthma in patients with AR, including bronchial hyperresponsiveness, uncovering by respiratory function tests of airway impairment, measurement of fractioned exhaled nitric oxide, given IgE sensitization pattern, and respiratory infections detected by nasal mucus samples or by particular microbiomes. Most of these risk predictors have been investigated too little or do not have consistent results, while various studies have confirmed that early bronchial impairment in AR patients, particularly concerning small airways, should be considered as prescriptive criteria for AIT. (www.actabiomedica.it)

The Effect of Adiposity Markers on Fractional Exhaled Nitric Oxide (FeNO) and Pulmonary Function Measurements

Background

The effect of increasing body weight on pulmonary function and the fractional exhaled nitric oxide (FeNO) remains controversial and the role of different body compositions in the relationship between obesity with pulmonary function and FeNO is still unrevealed. Thus, we aim to determine the effect of overweight/obesity on lung function and FeNO, focusing on the relationship with different body compositions.

Methods

Eighty-two non-smoker students (20 ± 1.9 years) were divided into two groups: 38 subjects with normal weight (BMI = 18.5–24.99) and 44 overweight/obese subjects (BMI ≥ 25). Spirometric parameters and FeNO were measured and compared between groups and were correlated with different adiposity markers.

Results

FeNO measurements were elevated in the overweight/obese group [median (IQR) 19.5 (13)] in comparison to the normal weight group [11 (10), p value = 0.017]. A positive correlation was found between FeNO measurements and body mass index (BMI), waist circumference, hip circumference, waist-hip ratio, and visceral fat percentage (all p values < 0.01). The absolute values of forced vital capacity (FVC) forced expiratory volume in the first second (FEV₁), peak expiratory flow (PEF), forced expiratory flow during mid-expiration (FEF_25–75%), and FEV₁/FVC ratio showed no significant differences between groups. However, the percentage of the predicted values of FEV₁ and FVC was significantly higher and the value of percentage predicted FEF_25–75% was reduced significantly in the overweight/obese subjects.

Conclusion

Increase in BMI could significantly increase airway inflammation as measured by FeNO, as well as on distal airway function as determined by the percentage predicted values of FEF_25–75%. A significant correlation was also identified between visceral fat and FeNO measurement.

Pragmatic Markers in the Management of Asthma: A Real-World-Based Approach

Bronchial hyperreactivity, reversible airflow limitation and chronic airway inflammation characterize asthma pathophysiology. Personalized medicine, i.e., a tailored management approach, is appropriate for asthma management and is based on the identification of peculiar phenotypes and endotypes. Biomarkers are necessary for defining phenotypes and endotypes. Several biomarkers have been described in asthma, but most of them are experimental and/or not commonly available. The current paper will, therefore, present pragmatic biomarkers useful for asthma management that are available in daily clinical practice. In this regard, eosinophil assessment and serum allergen-specific IgE assay are the most reliable biomarkers. Lung function, mainly concerning forced expiratory flow at 25-755 of vital capacity (FEF_25-75), and nasal cytology may be envisaged as ancillary biomarkers in asthma management. In conclusion, biomarkers have clinical relevance in asthma concerning both the endotype definition and the personalization of the therapy.