[show abstract][hide abstract] ABSTRACT: To determine the added value of measuring the forced mid-expiratory flow (FEF25-75%) and flow when 75% of the forced vital capacity (FVC) has been exhaled (FEF75%) over and above the measurement of the forced expiratory volume in one second (FEV1), FVC and FEV1/FVC ratio.Spirometric records with FEV1, FVC and FEF25-75% from 11,654 white males and 11,113 white females, aged 3-94 years, routinely tested in the pulmonary function laboratories of four tertiary hospitals. FEF75% was available in 8,254 males and 7,407 females.Predicted values and lower limits of normal, defined as the fifth percentile, were calculated for FEV1, FVC, FEV1/FVC, FEF25-75% and FEF75% using prediction equations from the Global Lung Function Initiative.There was very little discordance in classifying test results. In only 2.75% of cases the FEF25-75% , and in 1.29% of cases the FEF75% was below the normal range whereas FEV1, FVC and FEV1/FVC were within normal limits. Airways obstruction went undetected by FEF25-75% in 2.9%, by FEF75% in 12.3% of cases.Maximum mid-expiratory flow and flow towards the end of the forced expiratory manoeuvre do not contribute usefully to clinical decision making over and above information from FEV1, FVC and FEV1/FVC.
European Respiratory Journal 09/2013; · 6.36 Impact Factor
[show abstract][hide abstract] ABSTRACT: Redesign current grading of obstructive lung disease so that it is clinically relevant and free of biases related to age, height, sex and ethnic group.Spirometric records from 17,880 subjects (50.4% females) from hospitals in Australia and Poland, and 21,191 records (53.0% females) from 2 epidemiological studies (age 18-95 years).We adopted the American Thoracic Society and European Respiratory Society (ATS/ERS) criteria for airways obstruction based on an FEV1/(F)VC ratio below the 5th percentile and graded the severity of pulmonary function impairment using z-scores for FEV1 which signify how many standard deviations a result is from the mean predicted value.Using the lower limit of normal for FEV1/(F)VC and z-scores for FEV1 of -2, -2.5, -3 and -4 to delineate severity grades of airflow limitation leads to close agreement with ATS/ERS severity classifications and removes age, sex and height related bias.The new classification system is simple, easily memorised and clinically valid. It retains previously established associations with clinical outcomes and avoids biases due to the use of percent predicted FEV1. Combined with the Global Lung Function prediction equations it provides a world-wide diagnostic standard free of bias due to age, height, sex and ethnic group.
European Respiratory Journal 08/2013; · 6.36 Impact Factor
[show abstract][hide abstract] ABSTRACT: Spirometric Z scores by lambda-mu-sigma (LMS) rigorously account for age-related changes in lung function. Recently, the Global Lung Function Initiative (GLI) expanded LMS spirometric Z scores to multiple ethnicities. Hence, in aging populations, the GLI provides an opportunity to rigorously evaluate ethnic differences in respiratory impairment, including airflow limitation and restrictive pattern.
Using data from the Third National Health and Nutrition Examination Survey, including participants aged 40-80, we evaluated ethnic differences in GLI-defined respiratory impairment, including prevalence and associations with mortality and respiratory symptoms.
Among 3506 white Americans, 1860 African Americans and 1749 Mexican Americans, the prevalence of airflow limitation was 15.1% (13.9% to 16.4%), 12.4% (10.7% to 14.0%) and 8.2% (6.7% to 9.8%), and restrictive pattern was 5.6% (4.6% to 6.5%), 8.0% (6.9% to 9.0%) and 5.7% (4.5% to 6.9%), respectively. Airflow limitation was associated with mortality in white Americans, African Americans and Mexican Americans-adjusted HR (aHR) 1.66 (1.23 to 2.25), 1.60 (1.09 to 2.36) and 1.80 (1.17 to 2.76), respectively, but associated with respiratory symptoms only in white Americans-adjusted OR (aOR) 2.15 (1.70 to 2.73). Restrictive pattern was associated with mortality but only in white Americans and African Americans-aHR 2.56 (1.84 to 3.55) and 3.23 (2.06 to 5.05), and associated with respiratory symptoms but only in white Americans and Mexican Americans-aOR 2.16 (1.51 to 3.07) and 2.12 (1.45 to 3.08), respectively.
In an aging population, we found ethnic differences in GLI-defined respiratory impairment. In particular, African Americans had high rates of respiratory impairment that were associated with mortality but not respiratory symptoms.
[show abstract][hide abstract] ABSTRACT: Objective- To determine the diagnostic and interpretative consequences of adopting the Global Lungs 2012 (GLI-2012) spirometric prediction equations.Material- Spirometric records from 17,572 subjects (49.5% females), aged 18-85 years, from hospitals in Australia and Poland.Methods-We calculated predicted FEV1, FVC and FEV1/FVC, and lower limits of normal (LLN) using European Community for Steel and Coal (ECSC), National Health and Nutrition Examination Survey (NHANES III), and GLI-2012 equations. Obstruction was defined as FEV1/FVC <LLN, a restrictive pattern as FEV1/FVC>LLN and FVC <LLN. GOLD stage 2 and higher was defined as FEV1/FVC <70% and FEV1<80% predicted.Results- GLI-2012 equations produce similar predicted values for FEV1 and FVC compared with NHANES, but produce larger values than ECSC. Differences in the LLN lead to an important increase in the prevalence rate of a low FVC compared to ECSC, and a significant decrease compared to NHANES prediction equations. Adopting GLI-2012 equations has small effects on the prevalence rate of airway obstruction. GOLD stage 2-4 leads to>20% under-diagnosis of airway obstruction up to age 55 year, and to 16-23% over-diagnosis in older subjects. GLI-2012 equations increase the prevalence of a "restrictive spirometric pattern" compared to ECSC but decrease it compared to NHANES.
European Respiratory Journal 03/2013; · 6.36 Impact Factor
[show abstract][hide abstract] ABSTRACT: BACKGROUND: Among older persons, within the clinical context of respiratory symptoms and mobility, evidence suggests that improvements are warranted regarding the current approach for identifying respiratory impairment (ie, a reduction in pulmonary function). METHODS: Among 3583 white participants aged 65 to 80 years (Cardiovascular Health Study), we calculated the prevalence of respiratory impairment using the current spirometric standard from the Global Initiative for Obstructive Lung Disease (GOLD) and an alternative spirometric approach termed "lambda-mu-sigma" (LMS). Results for GOLD- and LMS-defined respiratory impairment were evaluated for their (cross-sectional) association with respiratory symptoms and gait speed, and for the 5-year cumulative incidence probability of mobility disability. RESULTS: The prevalence of respiratory impairment was 49.7% (1780/3583) when using the GOLD and 23.2% (831/3583) when using LMS. Differences in prevalence were most evident among participants who had no respiratory symptoms, with respiratory impairment classified more often by the GOLD (38.1% [326/855]) than LMS (12.3% [105/855]), as well as among participants who had normal gait speed, with respiratory impairment classified more often by the GOLD (46.4% [1003/2164]) than LMS (19.3% [417/2164]). Conversely, the 5-year cumulative incidence probability of mobility disability for respiratory impairment was higher for LMS than GOLD (0.313 and 0.249 for never-smokers, and 0.352 and 0.289 for ever-smokers, respectively), but was similar for normal spirometry by LMS or GOLD (0.193 and 0.185 for never-smokers, and 0.219 and 0.216 for ever-smokers, respectively). CONCLUSIONS: Among older persons, the LMS approach (vs the GOLD approach) classifies respiratory impairment less frequently in those who are asymptomatic and is more strongly associated with mobility disability.
The American journal of medicine 11/2012; · 4.47 Impact Factor
[show abstract][hide abstract] ABSTRACT: Schermer T, Quanjer Ph. Opsporen van COPD in de huisartsenpraktijk: wie is er eigenlijk ziek? Huisarts Wet 2007;50(8):85-9.De huidige COPD-richtlijnen, waaronder de NHG-Standaard COPD en de Global Initiative on Obstructive Lung Disease (GOLD), adviseren om luchtwegobstructie vast te stellen aan de hand van een ‘vaste’ afkapwaarde van 0,70 voor het quotiënt
van de éénsecondewaarde en de geforceerde vitale longcapaciteit (FEV1/FVC). Steeds meer onderzoek laat echter zien dat deze benadering een aanzienlijk percentage foutpositieve uitslagen tot gevolg
heeft, vooral in de categorie lichte tot matig ernstige obstructie. Daarnaast adviseren de richtlijnen om het FEV1, uitgedrukt als percentage van de voorspelde waarde, te gebruiken als maat voor de ernst van de obstructie. Ook deze werkwijze
leidt tot vertekening: kleine mensen en ouderen, en vooral ouderen die klein zijn, lijken een abnormaal laag FEV1 te hebben terwijl zij feitelijk géén respiratoire afwijking hebben. Er is dus behoefte aan betere regels om de aanwezigheid
en de ernst van luchtwegobstructie vast te stellen. Dit geldt in het bijzonder voor de huisarts, die vooral te maken heeft
met de vroege stadia van COPD. Een eerste stap naar een betere classificatie van luchtwegobstructies zou zijn om, in plaats
van een vaste waarde, de ‘ondergrens van normaal’ (LLN) voor het quotiënt FEV1/FVC als criterium te gebruiken.