Use of specific airway resistance to assess bronchodilator response in children

Background and objective: Changes in specific airway resistance (ΔsRaw) after bronchodilation, as measured by plethysmography and FEV₁, are frequently considered to be interchangeable indices of airway obstruction. However, the baseline relationship between these two indices is weak, and the value of ΔsRaw that best predicts FEV₁ reversibility in children has yet to be determined. The aim of this study was (i) to establish the sRaw cut‐off value that best distinguishes between positive and negative bronchodilator responses, as measured by FEV₁ reversibility; (ii) to determine whether the discrepancy between ΔsRaw and ΔFEV₁ might be explained by independent correlations between ΔFEV₁ and both ΔsRaw (mainly airway obstruction) and ΔFVC (airway closure); and (iii) to assess the effect of height and age on the relationship between ΔsRaw and ΔFEV₁. Methods: A retrospective study was performed in 481 children (median age 10.5 years, range 6.1–17.6) with actual or suspected asthma, for whom sRaw and spirometry data were obtained at baseline and after administration of a bronchodilator. Results: The sRaw cut‐off value that best predicted FEV₁ reversibility was a 42% decrease from baseline (P = 0.0001, area under the curve 0.70, sensitivity 55%, specificity 77%) and was independent of height and age. Changes in FEV₁ were significantly but independently related to ΔsRaw and ΔFVC (index of air trapping) (r = 0.40, P < 0.0001 and r = 0.39, P < 0.0001, respectively). Conclusions: A 42% decrease in sRaw predicted FEV₁ reversibility reasonably well, whereas a smaller decrease in sRaw failed to detect approximately one out of two positive responses detected by FEV₁, with no influence of height or age.     

Comparison of FEV(3), FEV(6), FEV(1)/FEV(3) and FEV(1)/FEV(6) with usual spirometric indices

Background and objective: Pulmonary function tests play an important role in the management of pulmonary diseases. One of the tests that are widely used is spirometry. Performing an acceptable spirometry manoeuvre according to the standards set by the American Thoracic Society/European Respiratory Society is difficult. The aim of this study was to compare forced expiratory volume in 3 s (FEV₃) and forced expiratory volume in 6 s (FEV₆) with forced vital capacity (FVC), and forced expiratory volume in 1 s FEV₁/FEV₃ and FEV₁/FEV₆ with FEV₁/FVC, in order to substitute the usual spirometric manoeuvres with manoeuvres that are easier to perform. Methods: In a cross‐sectional study, spirometry was performed for 588 subjects who were referred for occupational health evaluations. The accuracy of FEV₃, FEV₆, FEV₁/FEV₃ and FEV₁/FEV₆ was compared with that of FVC and FEV₁/FVC. Chi‐square tests and kappa tests were used to analyse the data. Results: Individuals with normal (n = 297) and abnormal spirometry (n = 291) were evaluated. The sensitivity, specificity, positive predictive value and negative predictive value of FEV₁/FEV₆, as compared with that of FEV₁/FVC for detecting obstruction, were 93.56, 99.32, 98.95 and 96.09, respectively. The sensitivity, specificity, positive predictive value and negative predictive value of FEV₆, as compared with that of FVC for detecting restriction, were 96.68, 98.65, 96.68 and 98.65, respectively. Conclusions: FEV₆ and FEV₁/FEV₆ can be used as surrogates for FVC and FEV₁/FVC, respectively, and these parameters showed acceptable sensitivity, specificity, positive predictive value and negative predictive value for occupational health evaluations.     

Evaluation of interrupter resistance in methacholine challenge testing in children

Bronchial hyperresponsiveness (BHR) is a key feature of asthma and is assessed using bronchial provocation tests. The primary outcome in such tests (a 20% decrease in forced expiratory volume in 1 sec (FEV₁)) is difficult to measure in young patients. This study evaluated the sensitivity and specificity of the interrupter resistance (R_int) technique, which does not require active patient participation, by comparing it to the primary outcome measure. Methacholine challenge tests were performed in children with a history of moderate asthma and BHR. Mean and individual changes in R_int and FEV₁ were studied. A receiver operating characteristic (ROC) curve was used to describe sensitivity and specificity of R_int. Seventy‐three children (median age: 9.2 years; range: 6.3–13.4 years) participated. There was a significant (P < 0.01) increase in mean R_int with increasing methacholine doses. However, individual changes of R_int showed large fluctuations. There was great overlap in change of R_int between children who did and did not reach the FEV₁ endpoint. A ROC curve showed an area under the curve of 0.65. Because of low sensitivity and specificity, the use of R_int to diagnose BHR in individual patients seems limited. Pediatr Pulmonol. 2011; 46:266–271. © 2011 Wiley‐Liss, Inc.     

Acute Bronchodilator Response Has Limited Value in Differentiating Bronchial Asthma from COPD

Background. Acute responsiveness to inhaled bronchodilators is often used to differentiate between bronchial asthma and chronic obstructive pulmonary disease (COPD). The response can be expressed in terms of a change in FEV₁ and FVC in several ways—as absolute change, change as percent of baseline value, or as percent of predicted value with different thresholds for a positive test. A comprehensive evaluation of the diagnostic value of these different methods of expressing the acute bronchodilator response has not been carried out. Methodology. Response to inhaled salbutamol was measured by spirometry in 200 asthmatics and 154 patients with COPD. The sensitivity, specificity, and positive and negative predictive values of different methods of expressing responsiveness were calculated. Receiver operative characteristic curves were obtained. Results. None of the expressions of response gave a clear-cut separation between the two diseases. A ΔFEV₁≥ 0.2 L gave the most satisfactory combination of sensitivity (73%) and specificity (80%) and the highest positive (82%) and negative predictive values (69%) for diagnosing asthma. These values were superior to those obtained for the ERS or the ATS criteria for reversibility (ΔFEV₁%predicted ≥ 9% and ΔFEV₁ of ≥ than 12% and 0.2 L over the baseline, respectively), which had almost similar diagnostic characteristics. This was confirmed by the area under curve of the ROC plots. Expressions of response in terms of changes in FVC were unsatisfactory in separating the two diseases. Conclusions. It was concluded that the test of acute bronchodilator responsiveness has limited diagnostic value in separating asthma and COPD.     

Significant Bronchodilator Responsiveness and “Reversibility” in a Population Sample

ABSTRACT

Chronic Obstructive Pulmonary Disease (COPD) is defined by being “not fully reversible”, most guidelines recommend measurement of lung function after the administration of a bronchodilator. The objective of this study was to compare bronchodilator responsiveness (significant improvement in the FEV₁ or FVC) to full-, partial- or “inverse’” reversibility in obstruction status in a population-based sample in Southeastern Kentucky. The study population was selected using random digit dialing of an adult population in Southeastern Kentucky as part of the Burden of Lung disease (BOLD) project. Lung function was assessed using spirometry pre- and post-bronchodilation. Subjects presence and severity of COPD was classified using modified Global Obstructive Lung Disease (GOLD) criteria. We examined the relation between changes in “obstruction” status (based on the FEV₁/ FVC of 0.7) and the presence of “significant bronchodilator responsiveness” (based on ≥ 12% improvement in the FEV₁ or the FVC). The final population with acceptable pre- and post-bronchodilator spirometry included 440 participants. 32/440 subjects (7.3%) changed from obstructed to unobstructed (full-reversibility), 19/440 (4.3%) changed from unobstructed to obstructed (“inverse”-reversibility), 389/440 (88.4%) had either no-change or partial-reversibility, and 65/440 (14.8%) had bronchodilator responsiveness. Among those with full-reversibility, only 9/32 (28.1%) had bronchodilator responsiveness, whereas among subjects with “inverse”-reversibility, 10/19 (52.6%) had bronchodilator responsiveness. Among all subjects with bronchodilator responsiveness, only 19/65 (29.2%) changed categories. Our findings suggest that significant bronchodilator responsiveness is not the same as “reversibility” of “obstruction”, even though these terms are often used interchangeably.     

Forced expiratory maneuvers in children aged 3 to 5 years

There is no consensus about reproducibility and reliability of spirometry in young children. We evaluated forced expiratory maneuvers from 98 children aged 3 to 5 years with a variety of respiratory disorders before and after bronchodilator treatment. Forced vital capacity (FVC) and forced expiratory volume in 1 sec (FEV,) were analyzed for reproducibility by the American Thoracic Society criteria and for reliability based on the coefficient of variation (CVYo). Over 90% of the patients cooperated, however, while 95% could exhale for at least 1 second, very few generated an FEV, on all 6 “best” efforts. This clearly improved with age. Of all patients nearly 60% performed reproducible pre-and postbronchodilator sets of FVC but only 32% performed reproducible sets of FEV₁. Based on the CV%, those patients who could reproducibly perform an FVC and FEV, did it quite reliably (mean CV%, 9.38 and 7.01 for FVC and FEV₁, respectively). We conclude that while some very young children can perform spirometry, reliability of performance cannot be assumed in this age group. Pediatr Pulmonol. 1994;18:144–149. © 1994 Wiley-Liss, Inc.     

Utility of bronchodilator response for asthma diagnosis in Latino preschoolers

BackgroundAsthma diagnosis in preschoolers is mostly based on clinical evidence, but a bronchodilator response could be used to help confirm the diagnosis. The objective of this study is to evaluate the utility of bronchodilator response for asthma diagnosis in preschoolers by using spirometry standardised for this specific age group.MethodsA standardised spirometry was performed before and after 200 mcg of salbutamol in 64 asthmatics and 32 healthy control preschoolers in a case-control design study.ResultsThe mean age of the population was 4.1 years (3–5.9 years) and 60% were females. Almost 95% of asthmatics and controls could perform an acceptable spirometry, but more asthmatics than controls reached forced expiratory volume in one second (FEV₁) (57% vs. 23%, p = 0.033), independent of age. Basal flows and FEV₁ were significantly lower in asthmatics than in controls, but no difference was found between groups in forced vital capacity (FVC) and FEV in 0.5 s (FEV_0.5). Using receiver operating characteristic (ROC) curves, the variable with higher power to discriminate asthmatics from healthy controls was a bronchodilator response (% of change from basal above the coefficient of repeatability) of 25% in forced expiratory flow between 25% and 75% (FEF_25–75) with 41% sensitivity, 80% specificity. The higher positive likelihood ratio for asthma equalled three for a bronchodilator response of 11% in FEV_0.5 (sensitivity 30%, specificity 90%).ConclusionsIn this sample of Chilean preschoolers, spirometry had a very high performance and bronchodilator response was very specific but had low sensitivity to confirm asthma diagnosis.     

Assessment of bronchial obstruction and its reversibility by shape indexes of the flow‐volume loop in asthmatic children

Asthma assessment by spirometry is challenging in children as forced expiratory volume in 1 s (FEV1) is frequently normal at baseline. Bronchodilator (BD) reversibility testing may reinforce asthma diagnosis but FEV1 sensitivity in children is controversial. Ventilation inhomogeneity, an early sign of airway obstruction, is described by the upward concavity of the descending limb of the forced expiratory flow‐volume loop (FVL), not detected by FEV1. The aim was to test the sensitivity and specificity of FVL shape indexes as β‐angle and forced expiratory flow at 50% of the forced vital capacity (FEF50)/peak expiratory flow (PEF) ratio, to identify asthmatics from healthy children in comparison to “usual” spirometric parameters. Seventy‐two school‐aged asthmatic children and 29 controls were prospectively included. Children performed forced spirometry at baseline and after BD inhalation. Parameters were expressed at baseline as z‐scores and BD reversibility as percentage of change reported to baseline value (Δ%). Receiver operating characteristic curves were generated and sensitivity and specificity at respective thresholds reported. Asthmatics presented significantly smaller zβ‐angle, zFEF50/PEF and zFEV1 (p ≤ .04) and higher BD reversibility, significant for Δ%FEF50/PEF (p = .02) with no difference for Δ%FEV1. zβ‐angle and zFEF50/PEF exhibited better sensitivity (0.58, respectively 0.60) than zFEV1 (0.50), and similar specificity (0.72). Δ%β‐angle showed higher sensitivity compared to Δ%FEV1 (0.72 vs. 0.42), but low specificity (0.52 vs. 0.86). Quantitative and qualitative assessment of FVL by adding shape indexes to spirometry interpretation may improve the ability to detect an airway obstruction, FEV1 reflecting more proximal while shape indexes peripheral bronchial obstruction.     

Ethnic differences in spirometry measurements in China: Results from a large community‐based epidemiological study

Background and objective

No previous studies have examined differences in spirometry measurements among ethnic populations in China, and factors which may influence ethnic differences are unclear. Our study aimed to investigate whether forced expiratory volume in 1 s (FEV₁) and forced vital capacity (FVC) differ among Han Chinese and other ethnic minorities in China.

Methods

We recruited 7137 individuals aged 35–70 years from four areas of China inhabited by ethnic minority groups between 2007 and 2009. We conducted spirometry tests for all available participants, and compared FEV₁ and FVC among Uygur, Hui, Mongolian, Dai and Han Chinese ethnicities, using nonlinear multiplicative regression models.

Results

A total of 2005 healthy never‐smokers were enrolled in the analysis. For all ethnicities, spirometry values increased with height and decreased with age; FEV₁ and FVC were consistently higher in males than in females. Compared with Han Chinese, FEV₁ was 4.42% (95% CI: 2.11–6.78%) higher in Mongolians, 4.08% (95% CI: 1.33–6.76%) lower in Uygurs, 4.39% (95% CI: 1.33–7.35%) lower in Hui people and 4.72% (95% CI: 1.80–7.55%) lower in Dai people, after adjusted for potential confounders including height, age, sex and place of residence. We observed similar differences for FVC.

Conclusions

We detected significant differences in spirometry measurements among ethnic populations in China. Such differences cannot be fully explained by demographic, anthropometric or socioeconomic factors, but may also be attributed to genetic background as well as indoor and outdoor environmental exposures that need further investigation.

     

Age is a predictor of a small decrease in lung function in children with sickle cell anemia

The longitudinal pattern of lung function in children with sickle cell anemia (SCA) has shown a decrease in FEV₁% predicted, a risk factor for death in adults with SCA, but predictors for this decline are poorly characterized. In a prospective longitudinal multi‐center cohort of children with SCA, we tested the hypotheses that: (1) FEV₁% predicted declines over time; and (2) SCA‐specific characteristics and therapy predict this decline. At three clinical centers, children with SCA (HbSS or HbSβ⁰ thalassemia), unselected for respiratory disease, were enrolled in the Sleep and Asthma Cohort (SAC) study. Study‐certified pulmonary function technicians performed spirometry and lung volumes. Each assessment was reviewed centrally. Predicted values were determined for TLC, FEV₁, FVC, and FEV₁/FVC ratio. A total of 197 participants, mean age 11.0 years at first testing (range 4‐19.3 years), had a minimum of three spirometry measurements, over an average of 4.4 years (range 1.1‐6.5 years) from baseline to endpoint. In a multivariable model, FEV₁% predicted declines by 0.3% for every additional year of age (95% CI ?0.56 to ?0.05, P = .020). Sex, asthma history, hemoglobin, reticulocyte count, white blood cell count, incidence rate of severe acute pain and acute chest syndrome episodes, and hydroxyurea therapy were not associated with a decline in FEV₁% predicted. In a large, rigorously evaluated, prospective cohort of an unselected group of children with SCA, FEV₁% predicted declines minimally over an average of 4 years, and none of the examined disease features predict the decline.     

Spirometry in an unselected group of 6-year-old children: the DARC birth cohort study

This study presents reference equations for spirometric parameters in 6-year-old children and evaluates the ability of spirometry to discriminate healthy children from children with asthma. Baseline spirometry and respiratory symptoms were assessed in 404 children participating in a longitudinal birth cohort study. Children with known asthma, possible asthma and a control group also performed bronchodilator measurements. At least two acceptable flow-volume curves at baseline were obtained by 368/404 children (91%). The two best values for FEV1 and FVC were within 5% of each other in 88% and 83% of children, respectively. Linear regression analyses for 242 children included in the reference population demonstrated height to be the main predictor of all spirometric indices except FEV1/FVC. FEV1, FEV75, and FVC correlated reasonably to anthropometric data in contrast to flow parameters. Gender differences were found for FEV1, FVC, and FEV75, but not for flow parameters. Asthma was diagnosed in 25/404 children. Baseline lung function in healthy children and children with asthma overlapped, although asthmatic children could be discriminated to some extent. Bronchodilator tests showed a difference in Delta FEV1(mean) between healthy children and children with asthma (3.1% vs. 6.1%, P < 0.05). At a cut-off point of Delta FEV1 = 7.8%, bronchodilator tests had a sensitivity of 46% and a specificity of 92% for current asthma. Spirometry including bronchodilator measurements was demonstrated to be feasible in 6-year-old children and reference values were determined. Spirometry aids the diagnosis of asthma in young children, but knowledge on sensitivity and specificity of these measurements is a prerequisite.     

The effect of age on bronchodilator responsiveness

The relationship between age and bronchodilator responsiveness (BDR) in children has not been studied using objective parameters. The aim of this study was to seek such a relationship in young asthmatic children using dose—response curves (DRC). Fourteen asthmatic subjects (age 3–9 years) with a forced expiratory volume in 1 sec (FEV₁) less than 80% predicted were studied after being trained to use a spirometer reliably. Each subject completed a DRC by inhaling 5 doses of salbutamol (albuterol) at 15 min intervals until a cumulative total of 6.84 mg of salbutamol had been administered. FEV₁, forced vital capacity (FVC), and forced expiratory flow at mid vital capacity (FEF_25?75) were measured before and after each nebulization. In addition, arterial oxygen saturation (Sa_O2) and heart rate (HR) were measured in some of the subjects. All lung function parameters, Sa_O2 and HR increased significantly between baseline and completion of the DRC. A significant age effect on BDR was detected in FEV₁ and FVC, with older children showing a greater response than young ones. The response had plateaued after the maximum dose in the younger but not in the older children. These findings suggest that the level of response to a bronchodilator increases significantly with increasing age in young asthmatics. © 1993 Wiley-Liss, Inc.     

Spirometry in 5-year-olds--validation of current guidelines and the relation with asthma

INTRODUCTION: Spirometry is more frequently measured in younger children. Our primary aim was to validate 2005 ATS-ERS Task Force standards for spirometry in adults and older children among a population of 5-year-old children. Our secondary aim was to relate spirometry to asthma symptoms. METHODS: Children were participants in a longitudinal cohort study where asthma symptoms and spirometry were assessed. RESULTS: Of the 827 children assessed, spirometry was obtained in 638 (85 with wheeze). A back-extrapolated volume/FVC ratio of <5% was achieved in 99% of children, the best two FVC were < or =150 ml of each other in 89% and three efforts were obtained within six attempts in 88%. The best two FVC were within 10% of each other in 82% of children. Only 13% achieved a forced expiratory time (FET) of > or =3 sec, whereas 80% had an FET of > or =1 sec. All criteria (including FET > or =1 s and FVC < or =10%) were met in 400 (65%) of the 638 children. Most spirometric indices were reduced in association with current wheeze and a history of asthma; children with current wheeze had a mean reduction of 0.65 FEV(1) z score compared to healthy children, P < 0.001. An FEV(1) z score of -1.0 had 82% sensitivity but only 50% specificity for current wheeze, the corresponding numbers for an FEF(50) z score of -1.0 being 79% and 71%. CONCLUSIONS: The standards for spirometry are mostly achieved in this age group but are not necessarily valid and require revision. Reliable spirometry is feasible in 5-year-old children where reduced measurements are associated with asthma symptoms and in whom FEF(50) appears to be the most discriminatory variable.     

Effect of Heliox- and Air-Driven Nebulized Bronchodilator Therapy on Lung Function in Patients with Asthma

Background

This study compares the effect of heliox-driven to that of air-driven bronchodilator therapy on the pulmonary function test (PFT) in patients with different levels of asthma severity.

Methods

One-hundred thirty-two participants were included in the study. Participants underwent spirometry twice with bronchodilator testing on two consecutive days. Air-driven nebulization was used one day and heliox-driven nebulization the other day in random order crossover design. After a baseline PFT, each participant received 2.5 mg of albuterol sulfate nebulized with the randomized driving gas. Post bronchodilator PFT was repeated after 30 min. The next day, the exact same protocol was repeated, except that the other driving gas was used to nebulize the drug. Participants were subgrouped and analyzed according to their baseline FEV₁ on day 1: Group I, FEV₁ ≥80 %; Group II, 80 % > FEV₁ > 50 %; Group III, FEV₁ ≤50 %. The proportion of participants with greater than 12 % and 200-mL increases from their baseline FEV₁ and the changes from baseline in PFT variables were compared between heliox-driven versus air-driven bronchodilation therapy.

Results

The proportion of participants with >12 % and 200-mL increases from their baseline FEV₁ with air- or heliox-driven bronchodilation was not different with respect to the proportion of participants with baseline FEV₁ ≥80 % (20 vs. 18 %, respectively) and 80 % > FEV₁ > 50 % (36 vs. 43 %, respectively), but it was significantly greater with heliox-driven bronchodilation in participants with FEV₁ ≤50 % (43 vs. 73 %, respectively; p = 0.01). Changes from baseline FVC, FEV₁, FEV₁/FVC, FEF_25–75 %, FEF_max, FEF_25 %, FEF_50 %, and FEF_75 % were significantly larger with heliox-driven versus air-driven bronchodilation in participants with baseline FEV₁ ≤50 %.

Conclusion

Improvements in PFT variables are more frequent and profound with heliox-driven compared to air-driven bronchodilator therapy only in asthmatic patients with baseline FEV₁ ≤50 %.     

Detection and prevalence of chronic obstructive pulmonary disease in a cardiovascular clinic: evaluation using a hand held FEV₁/FEV₆ meter and questionnaire

Background and objective: COPD is one of the leading causes of morbidity and mortality worldwide, and its prevalence continues to increase. Although spirometry is indispensable for the diagnosis of COPD, other simple and reliable tools are necessary for screening of COPD because spirometry is not widely available. This study investigated the usefulness of a combination of an electronic FEV₁/FEV₆ meter (PiKo‐6) with a COPD questionnaire as a screening method in patients with cardiovascular diseases. Methods: The PiKo‐6 and the COPD questionnaire of the International Primary Care Airways Group were used to screen patients attending a cardiovascular outpatient clinic. Patients with FEV₁/FEV₆ < 70% were defined as having airflow limitation. Patients diagnosed with airflow limitation underwent spirometry. Using data from the PiKo‐6 and the COPD questionnaire, patients were assigned to a COPD group or a non‐COPD group. The relationship between PiKo‐6 measurements and spirometry was also evaluated. Results: Among 753 patients, 82 (10.9%) showed airflow limitation when assessed with the PiKo‐6. Of these patients, 79 (10.5%) were assigned to the COPD group. FEV₁, FEV₆ and FEV₁/FEV₆, as measured with the PiKo‐6, correlated significantly with FEV₁, FVC and FEV₁/FVC, respectively, as measured by spirometry (r = 0.865, 0.751 and 0.57). Among the cardiovascular comorbidities, heart failure and ischaemic heart disease showed slightly stronger associations with airflow limitation (13.8% and 12.5%, respectively). Conclusions: Combination of the PiKo‐6 with a COPD questionnaire may be a useful and feasible method of identifying undiagnosed COPD patients attending a cardiovascular outpatient clinic.     

The reliability and utility of spirometry performed on people with asthma in community pharmacies

Objective: To investigate the reliability and the utility of spirometry generated by community pharmacists participating in two large asthma intervention trials of 892 people. Methods: The Pharmacy Asthma Care Program (PACP) and the Pharmacy Asthma Management Service (PAMS) involved up to four visits to the pharmacy over 6 months for counseling and goal setting. Pharmacists performed spirometry according to ATS/ERS guidelines to inform management. The proportion of A–E, F quality tests, as per EasyOne? QC grades, were recorded. Lung function results between visits and for participants referred/not referred to their general practitioner on the basis of spirometry were compared. Results: Complete data from 2593 spirometry sessions were recorded, 68.5% of spirometry sessions achieved three acceptable tests with between-test repeatability of 150?ml or less (A or B quality), 96% of spirometry sessions included at least one test that met ATS/ERS acceptability criteria. About 39.1% of participants had FEV₁/FVC values below the lower limit of normal (LNN), indicating a respiratory obstruction. As a result of the service, there was a significant increase in FEV₁ and FEV₁/FVC and asthma control. Lung function values were significantly poorer for participants referred to their general practitioner, compared with those not referred, on the basis of spirometry. Conclusions: Community pharmacists are able to reliably achieve spirometry results meeting ATS/ERS guidelines in people with asthma. Significant improvements in airway obstruction were demonstrated with the pharmacy services. Pharmacists interpreted lung function results to identify airway obstruction for referral, making this a useful technique for review of people with asthma in the community.     

Early wheeze as reported by mothers and lung function in 4‐year‐olds. Prospective cohort study in Krakow

The purpose of the study was to check the hypothesis that early wheezing as reported by mothers would be associated with reduced lung function in 4‐year olds. Study participants were recruited prenatally, as part of a prospective cohort study on the respiratory health of young children exposed to various ambient air pollutants. After delivery, infants were followed over 4 years and the interviewers visited participants at their home to record respiratory symptoms every 3 months in the child's first 2 years of life and every 6 months in the 3rd and 4th years. In the 4th year of follow‐up, children were invited for standard lung function testing by spirometry quantified by forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV₁), and forced expiratory volume in 0.5 sec (FEV_0.5) levels. Out of 258 children attending spirometry testing 139 performed at least two acceptable exhalation efforts. Cohort children with acceptable spirometric measurements did not differ with respect to wheezing experience and exposure characteristics from those without. The study shows that episodic wheeze was reported in 28.1% of 4‐year olds, 6.5% had transient wheeze, and 4.3% had recurrent wheeze. There was an increased frequency of wheezing symptoms and their duration in transient and recurrent wheezers. Adjusted multivariable regression models for gender and height showed that children who reported more than two episodes of wheezing at any point over the follow‐up had FVC values lower by 120.5 ml (P = 0.016) and FEV₁ values lower by 98.3 ml (P = 0.034) compared to those who did not report any wheezing; children experiencing more than 10 wheezing days by age 4 showed FVC deficit of 87.4 ml (P = 0.034) and FEV₁ values of 65.7 ml (P = 0.066). The ratios of FEV₁/FVC%, and FEV_0.5/FVC% were neither associated with wheezing episodes nor wheezing days. In recurrent wheezers, lung function decrement amounted to 207 ml of FVC, 175 ml of FEV₁, and 104 ml of FEV_0.5. In conclusion, our findings show that wheezing experience during early postnatal life may be associated with lung function deficit of restrictive character in preschool children and detailed history of wheeze in early postnatal life, even though not physician‐confirmed, may help define the high risk group of children for poor lung function testing. Pediatr. Pulmonol. 2010; 45:919–926. © 2010 Wiley‐Liss, Inc.     

The Global Lung Initiative 2012 reference values reflect contemporary Australasian spirometry

We aimed to ascertain the fit of the European Respiratory Society Global Lung Initiative 2012 reference ranges to contemporary Australasian spirometric data. Z‐scores for spirometry from Caucasian subjects aged 4–80 years were calculated. The mean (SD) Z‐scores were 0.23 (1.00) for forced expirtory volume in 1 s (FEV₁), 0.23 (1.00) for forced vital capacity (FVC), ?0.03 (0.87) for FEV₁/FVC and 0.07 (0.95) for forced expiratory flows between 25% and 75% of FVC. These results support the use of the Global Lung Initiative 2012 reference ranges to interpret spirometry in Caucasian Australasians.     

Prevalence and features of asthma–chronic obstructive pulmonary disease overlap in Northern Italy general population

Objective: There is controversy about the diagnostic criteria, prevalence, symptoms, and spirometry characteristics of asthma–chronic obstructive pulmonary disease (COPD) overlap (ACO). Recent data indicate that the fixed method for diagnosing airway obstruction (AO) may overestimate ACO prevalence in the elderly, and a variable method may be more accurate. We aimed at estimating ACO prevalence in a general population sample and comparing patient and clinical features in subjects with ACO, COPD, and asthma. Methods: We analyzed data from a cross-sectional study estimating COPD prevalence in randomly selected adults aged 20–79 years in Verona, Italy, and estimated prevalence and analyzed characteristics of asthma, COPD, and ACO. ACO was defined as AO (Forced Expiratory Volume in one second–FEV₁/ Forced Vital Capacity–FVC < Lower Limit of Normal–LLN), highly positive bronchodilator test (≥15% increase in FEV₁ and FVC ≥400 mL), and personal self-reported history of physician diagnosed asthma and atopy. Results: One thousand two hundred and thirty-six patients were included; 207 (16.7%) had asthma, COPD, or ACO (mean ages: 61.2, 59.7, and 57.2 years, respectively). The 3 groups had similar clinical and demographic variables; however, spirometry revealed differences between ACO and COPD patients, particularly post-bronchodilator FEV₁ reversibility, which was detected in ACO and asthma patients but not in those with COPD. Conclusion: ACO prevalence in Northern Italy was estimated at 2.1%, in the range of values reported by previous studies. Marked differences between ACO and COPD revealed by spirometry may have important clinical implications in terms of treatment for patients with ACO.