Waist circumference associated with pulmonary function in children

In adults abdominal obesity is related to lung dysfunction and waist circumference (WC) predicts pulmonary function. It is not known how WC affects pulmonary function in children. A cross‐sectional study of 718 children 6–17 years of age was conducted in a rural community to determine the predictability of WC for pulmonary function in children. Height, weight, WC, and pulmonary function were measured. Multivariate analysis was conducted. WC was positively associated with FVC and FEV₁ and was more strongly associated with FVC than with FEV₁. Increase in WC significantly predicted a reduction in FEV₁/FVC. After adjustment for sex, age, and height, an increase of 1 cm for WC was associated with an increase of 7 ml of FVC and 4 ml of FEV₁, and with an increase of 4 ml of FVC and 2 ml of FEV₁ with an additional adjustment for weight. Height and weight were not significantly associated with FEV₁/FVC. WC but not body mass index predicted a decline of FEV₁/FVC. WC had a larger impact on FVC than FEV₁. WC, but not BMI, was negatively associated with FEV₁/FVC in children. Pediatr Pulmonol. 2009; 44:216–221. © 2009 Wiley‐Liss, Inc.     

Baseline and post-bronchodilator interrupter resistance and spirometry in asthmatic children

In children unable to perform reliable spirometry, the interrupter resistance (R_int) technique for assessing respiratory resistance is easy to perform. However, few data are available on the possibility to use R_int as a surrogate for spirometry. We aimed at comparing R_int and spirometry at baseline and after bronchodilator administration in a large population of asthmatic children. We collected retrospectively R_int and spirometry results measured in 695 children [median age 7.8 (range 4.8–13.9) years] referred to our lab for routine assessment of asthma disease. Correlations between R_int and spirometry were studied using data expressed as z‐scores. Receiver operator characteristic curves for the baseline R_int value (z‐score) and the bronchodilator effect (percentage predicted value and z‐score) were generated to assess diagnostic performance. At baseline, the relationship between raw values of R_int and FEV₁ was not linear. Despite a highly significant inverse correlation between R_int and all of the spirometry indices (FEV₁, FVC, FEV₁/FVC, FEF_25–75%; P < 0.0001), R_int could detect baseline obstruction (FEV₁ z‐score ≤ ?2) with only 42% sensitivity and 95% specificity. Post‐bronchodilator changes in R_int and FEV₁ were inversely correlated (rhô = ?0.50, P < 0.0001), and R_int (≥35% predicted value decrease) detected FEV₁ reversibility (>12% baseline increase) with 70% sensitivity and 69% specificity (AUC = 0.79). R_int measurements fitted a one‐compartment model that explained the relationship between flows and airway resistance. We found that R_int had poor sensitivity to detect baseline obstruction, but fairly good sensitivity and specificity to detect reversibility. However, in order to implement asthma guidelines for children unable to produce reliable spirometry, bronchodilator response measured by R_int should be systematically studied and further assessed in conjunction with clinical outcomes. Pediatr Pulmonol. 2012. 47:987–993. © 2012 Wiley Periodicals, Inc.     

Factors predicting future ACS episodes in children with sickle cell anemia

While a doctor‐diagnosis of asthma is associated with an increased risk of pain and acute chest syndrome (ACS) in children with sickle cell anemia (SCA), little is known about the relationship between specific asthma characteristics and clinical factors and future morbidity in children with SCA. We evaluated the relationship between (i) asthma risk factors at the time of a clinical visit (respiratory symptoms, maternal history of asthma, allergy skin tests, spirometry results) and (ii) the known risk factor of ACS early in life, on prospective pain and ACS episodes in a cohort of 159 children with SCA followed from birth to a median of 14.7 years. An ACS episode prior to 4 years of age, (incidence rate ratio [IRR] = 2.84; P < 0.001], female gender (IRR = 1.80; P = 0.009), and wheezing causing shortness of breath (IRR = 1.68; P = 0.042) were associated with future ACS rates. We subsequently added spirometry results (obstruction defined as FEV₁/FVC less than the lower limits of normal; and bronchodilator response, FEV₁ ≥ 12%) and prick skin test responses to the model. Only ≥ 2 positive skin tests had a significant effect (IRR 1.87; P = 0.01). Thus, early in life ACS events, wheezing causing shortness of breath, and ≥ 2 positive skin tests predict future ACS events. Am. J. Hematol. 89:E212–E217, 2014. © 2014 Wiley Periodicals, Inc.     

Spirometry values in a Greek population: Is there an appropriate reference equation?

Background and objective: Most published reference values for lung function test (LFT) parameters introduce systematic bias. The aim of this study was to compare measured values of FEV₁ and FVC with the corresponding normal predicted values in a Greek population, and to produce reference equations for LFT parameters in this population. Methods: In a cross‐sectional study conducted in Macedonia, Greece, 1080 adult healthy, non‐smokers (432 men, 648 women, aged 18–80 years), underwent spirometry. Measured values of FVC and FEV₁ were compared with predicted values determined using three existing sets of reference equations: one recently derived from a European population and two others widely used in Europe (European Coal and Steel Community; ECSC) and the USA (National Health and Nutrition Examination Survey; NHANES III). Height and age were entered into the multivariate regression analysis to produce reference equations for LFT parameters. Results: All three published sets of equations underpredicted FEV₁ in men. FVC was accurately predicted by all equations except NHANES III. The discrepancy was even greater among women; the ECSC equation underpredicted both FEV₁ and FVC, the NHANES III equation overpredicted both FEV₁ and FVC, while the third set of equations accurately predicted FEV₁ but overpredicted FVC. The derived reference equation for FEV₁ in men was ?0.28 × age + 0.057 × height ? 4.91, and in women ?0.021 × age + 0.039 × height ? 2.58. The derived reference equation for FVC in men was ?0.28 × age + 0.071 × height ? 6.763, and in women ?0.019 × age + 0.056 × height ? 5.018. Conclusions: Measured FEV₁ and FVC values in a Greek population differed significantly from those predicted using previously published reference equations. The new locally derived spirometry reference equations may be more suitable for evaluation of lung function in everyday practice.     

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.     

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.     

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.     

Nocturnal Reflux in Children and Adolescents with Persistent Asthma and Gastroesophageal Reflux

Background. A higher frequency of nocturnal gastroesophageal reflux (GER) in adult patients with respiratory symptoms has been demonstrated. The aim of this study was to determine the prevalence of nocturnal GER by using prolonged intraesophageal pH monitoring and compare it with spirometry results in children with persistent asthma. Methods. Thirty-eight patients with persistent asthma for at least 2 years were studied. Gastrointestinal symptoms suggestive of GER were considered as regurgitation, heartburn, and abdominal pain. All patients underwent prolonged intraesophageal pH study and spirometry. GER was considered positive when a reflux index (RI) was higher than 5%. Forced vital capacity (FVC), forced expiratory volume in 1 second (FEV₁), forced mid-expiratory flow rate (FEF_{25 ? 75%}), and FEV₁/FVC ratio were measured. Results. Median age was 10 years of age (range 5 to 15) and 58% were male; GER prevalence was 47.3%. Median (range) of reflux index during supine and upright periods from GER patients were, respectively, 8.7% (3.2 to 23.6) and 10.5% (5.2 to 15.0) (p = 0.913), and only FEF_{25 ? 75%} was below the predicted value: 54.5% (39.4 to 96.9). Reflux index was not significantly correlated with FVC, FEV₁ and FEF_{25 ? 75%}. Conclusions. A high prevalence of GER was found in children and adolescents with persistent asthma, equally distributed in the supine (nocturnal) and upright positions. There was no correlation with pulmonary function test.     

Reference Values and Prediction Equations for FVC and FEV1 in the Greek Elderly

Spirometry prediction equations obtained from middle-age adults, when extrapolated for the elderly, may lead to inaccurate interpretations. The purpose of this study was to determine prediction equations for forced vital capacity (FVC) and forced expiratory volume (FEV₁) in the Greek elderly population. Spirometry prediction equations for normal FVC and FEV₁ have been derived from tests on 71 healthy persons (38 men, 33 women) aged older than 60 years (range, 65–85 years), nonsmokers, white race, urban population using techniques and equipment that meet American Thoracic Society recommendations. Regression analysis using age, height, and weight as independent variables was used to provide prediction equations and values for both sexes. The FVC age coefficient in this healthy group was about 47.19 mL/y for elderly men and 34.27 mL/y for elderly women, and the FEV₁ age coefficient was about 52.8 mL/y for elderly men and 46.4 mL/y for elderly women . Values from this study predicted equations were compared with those from some of the most commonly used sources of spirometry predicted equations. The FVC and FEV₁ predicted values were found to be of less mean square error than that of other compared studies. Higher correlation is between FVC and FEV₁ predicted values by the present model and FVC and FEV₁ observed values in both sexes. The higher correlation between FVC and FEV₁ predicted and observed from this study allows the use of our model for predicting in a rather reliable way the FVC and FEV₁ for elderly Greek individuals. Accepted for publication: 25 April 2000     

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.     

The Diagnostic Importance of a Reduced FEV1/FEV6

Abstract

Background: On spirometry the FEV₁/FEV₆ ratio has been advocated as a surrogate for the FEV₁/FVC. The significance of isolated reductions in either the FEV₁/FEV₆ or FEV₁/FVC is not known. Methods: First-time adult spirograms (n = 22,837), with concomitant lung volumes (n = 12,040), diffusion (n = 14,154), and inspiratory capacity (n = 12,480) were studied. Four groups were compared. 1) Only FEV₁/FEV₆ reduced (n = 302). 2) Only FEV₁/FVC reduced (n = 1158). 3) Both ratios reduced (n = 6593). 4) Both ratios normal (n = 14,784). Results: In patients with obstructed spirometry (either a reduced FEV₁/FVC and/or FEV₁/FEV₆), 3.8% only had a reduced FEV₁/FEV₆, while 14.4% only had a reduced FEV₁/FVC. The mean FEV₁ was lower when both ratios were reduced. The group with only a reduced FEV₁/FEV₆, compared to only the FEV₁/FVC reduced, had a lower FEV₁, FVC, BMI, Expiratory Time, and IC (p values < 0.0001). DLCO was also lower (p = 0.005), and the FEV₁/FVC and RV/TLC were higher (p values < 0.0001). When the patients with only a reduced FEV₁/FEV₆ had a subsequent spirogram, 60% had a reduced FEV₁/FVC when their mean expiratory times were 3.5 seconds longer. Ninety percent of this group had strong clinical evidence of airways obstruction. Conclusions: The FEV₁/FEV₆ is not as sensitive as the FEV₁/FVC for diagnosing airways obstruction, but in the presence of a normal FEV₁/FVC, subjects have greater physiologic abnormalities than when only the FEV₁/FVC is reduced. The FEV₁/FEV₆ ratio should not replace the FEV₁/FVC as the standard for airways obstruction, but there is benefit including this measurement to identify individuals with greater air trapping and diffusion abnormalities.     

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.     

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.

     

Validación de las ecuaciones propuestas por la Iniciativa Global de Función Pulmonar (GLI) y las de Todas las Edades para espirometría forzada en preescolares sanos españoles

Introduction

Recent publication of multi-ethnic spirometry reference equations for subjects aged from 3-95 years aim to avoid age-related discontinuities and provide a worldwide standard for interpreting spirometric test results.

Ratio of waist circumference to chest circumference is inversely associated with lung function in Chinese children and adolescents

Background and objective: In White children, waist circumference (WC) is positively correlated with forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV₁). Because fat distribution differs among different races, the relationship between WC and lung function in Asian children may differ from that in White children. The present study aimed to examine the effect of WC on ventilatory function in Chinese children. Methods: A cross‐sectional study was performed on 1572 healthy subjects aged 9–18 years. Height, weight, chest circumference (CC), WC and lung function (FVC, FEV₁, peak expiratory flow (PEF) and maximal mid‐expiratory flow (MMEF)) were measured. To avoid the problem of colinearity, a model that combined CC and WC as the waist‐to‐chest ratio (WCR) was used. The relative contributions of WCR and body mass index (BMI) to spirometric parameters were determined by linear regression analysis. Results: WCR was inversely associated with all spirometric parameters. On average, each 0.01 increase in WCR was associated with decreases of 8.14 mL for FVC, 9.36 mL for FEV₁, 6.54% for FEV₁/FVC, 19.81 mL/s for PEF and 17.25 mL/s for MMEF. BMI was positively associated with all spirometric parameters except FEV₁/FVC. These results suggest that WC was inversely associated with lung function parameters. Conclusions: Inverse associations were identified between WCR, as well as WC, and lung function in a population of Chinese children. The underlying mechanisms need to be further explored.     

Importance of slow vital capacity in the detection of airway obstruction

OBJECTIVE:

To investigate the presence of airway obstruction by determining the FEV₁/FVC and FEV₁/slow vital capacity (SVC) ratios.

METHODS:

This was a quantitative, retrospective cross-sectional study. The sample comprised 1,084 individuals who underwent spirometry and plethysmography in a central hospital in Lisbon, Portugal. The study sample was stratified into six groups, by pulmonary function.

RESULTS:

The analysis of the FEV₁/FVC ratio revealed the presence of airway obstruction in 476 individuals (43.9%), compared with 566 individuals (52.2%) for the analysis of the FEV₁/SVC ratio. In the airway obstruction, airway obstruction plus lung hyperinflation, and mixed pattern groups, the difference between SVC and FVC (SVC − FVC) was statistically superior to that in the normal pulmonary function, reduced FEF, and restrictive lung disease groups. The SVC − FVC parameter showed a significant negative correlation with FEV₁ (in % of the predicted value) only in the airway obstruction plus lung hyperinflation group.

CONCLUSIONS:

The FEV₁/SVC ratio detected the presence of airway obstruction in more individuals than did the FEV₁/FVC ratio; that is, the FEV₁/SVC ratio is more reliable than is the FEV₁/FVC ratio in the detection of obstructive pulmonary disease.     

Efficacy of tiotropium in COPD patients from Asia: a subgroup analysis from the UPLIFT trial

Background and objective: Studies in respiratory diseases other than chronic obstructive pulmonary disease suggest potentially differing responses to medications among patients from different regions. We report a subgroup analysis of patients recruited to Asian centres from a previously reported 4‐year COPD trial. Methods: Subgroup analysis from a randomized, double‐blinded, placebo‐controlled trial of tiotropium 18 µg daily in COPD. Primary end‐point was rate of decline in FEV₁. Secondary end‐points included spirometry at individual time points, health‐related quality of life (St George's Respiratory Questionnaire), exacerbations and mortality. Results: Of 5992 patients, 362 were from Asian centres (100 from Japan). Mean age 66 years, 95% men, 13% current smokers, BMI: 21 kg/m²; post‐bronchodilator FEV₁: 44% predicted; St George's Respiratory Questionnaire total score: 44 units. No treatment effect was observed for rate of decline in FEV₁ although annual decline was less in Asian patients. Morning pre‐bronchodilator FEV₁ and forced vital capacity improved in Asian patients (P < 0.05). Tiotropium reduced number of exacerbations (rate ratio (95% confidence interval (CI)): 0.73 (0.57–0.94)). Hazard ratios (95%CI) for exacerbations and hospitalized exacerbations (tiotropium/control) were 0.81 (0.62–1.05) and 0.85 (0.61–1.19), respectively. St George's Respiratory Questionnaire total score improved by 1.5–6.1 units (P < 0.05 for months 18, 24, 30 and 36) with tiotropium. Fatal events occurred in 34 tiotropium (18.5%) and 42 control (23.6%) patients. Conclusions: In COPD patients from Asia, tiotropium improves lung function, improves health‐related quality of life and reduces exacerbations over 4 years of treatment.     

Culturally Appropriate Outreach Specialist Respiratory Medical Care Improves the Lung Function of Children in Regional and Remote Queensland

Background and Objectives

Indigenous Respiratory Outreach Care (IROC) is a culturally appropriate specialist respiratory service established to deliver multidisciplinary respiratory care to regional and remote Queensland communities. Our objective was to evaluate the impact of an outreach specialist respiratory service on the spirometry of children attending IROC clinics, particularly Indigenous children with asthma and bronchiectasis.

Methods

Retrospective single-arm cohort study of 189 children who performed spirometry at twelve sites across regional and remote Queensland between October 2010 and December 2017. Each child’s baseline spirometry was compared to their best spirometry at follow-up visit occurring within (1) 12 months of their most recent visit with at least 12 months of specialist care and; (2) each year of their first 3 years of care.

Results

Forced expiratory volume in one second (FEV₁) and forced vital capacity (FVC) z-scores improved significantly across the whole group from baseline to follow-up (change in z-scores (Δz) of FEV₁ = 0.38, 95% CI 0.22, 0.53; ΔzFVC = 0.36, 95% CI 0.21, 0.51). In subgroup analyses, lung function significantly improved in Indigenous children (n = 141, ΔzFEV₁ = 0.37, 95% CI 0.17, 0.57; ΔzFVC = 0.36, 95% CI 0.17, 0.55) including those with asthma (n = 117, ΔzFEV₁ = 0.41, 95% CI 0.19, 0.64; ΔzFVC = 0.46, 95% CI 0.24, 0.68) and bronchiectasis (n = 38, ΔzFEV₁ = 0.33, 95% CI 0.07, 0.59; ΔzFVC = 0.26, 95% CI − 0.03, 0.53). Significant improvements in FEV₁ and FVC were observed within the first and second year of follow-up for Indigenous children, but not for non-Indigenous children.

Conclusion

The IROC model of care in regional and remote settings leads to significant lung function improvement in Indigenous children with asthma and bronchiectasis.

     

Effects of changing reference values and definition of the normal range on interpretation of spirometry

Background and objective: Recent spirometry reference studies are arguably the most valid ever performed and the ATS/ERS now recommend the National Health and Nutrition Assessment Survey (NHANES) equations for North America. It is timely to consider adopting these reference values in Australasia; however, an evaluation of the consequences of such a change is required. Methods: We analysed data from 1108 patients tested in two pulmonary function laboratories in public hospitals. Lower limits of normal (LLN) were calculated using European Community for Steel and Coal (ECSC) (1993), Knudson (1983), NHANES (1999) and Health Survey of England (HSE) (2004) equations and used to define restriction (FVC < LLN) and obstruction (FEV₁/FVC < LLN). This interpretative strategy was also compared with the GOLD definition of obstruction (FEV₁/FVC < 70%). Results: Average age for all patients (50% female) was 60 years (range: 20–91). The mean predicted FVC from NHANES and HSE were similar and consistently higher than those from ECSC and Knudson (average 270 mLs). This translates into a 76% increase in the incidence of ‘restrictive’ interpretations using NHANES data compared with ECSC and Knudson, and a smaller increase of 40% for HSE. Using FEV₁/FVC < 70% to diagnose obstruction in those over 65 years would result in false positive rates of approximately 28%. Using the same definition in a younger group (<50 years old) results in a false negative rate of approximately 14%. Conclusions: Changing to either NHANES or HSE predicted values will significantly increase the rate of ‘restrictive’ interpretation, and alter the rate of obstructive findings. The NHANES and HSE data confirm that using FEV₁/FVC < 70% to define obstruction causes misdiagnosis in elderly and younger subjects.