Quality of spirometry tests performed by 9893 adults in 14 countries: the BOLD Study.

OBJECTIVE: to determine the ability of participants in the Burden of Obstructive Lung Disease (BOLD) study to meet quality goals for spirometry test session quality and to assess factors contributing to good quality. METHODS: Following 2 days of centralized training, spirometry was performed pre- and post-bronchodilator (BD) at 14 international sites, in random population-based samples of persons aged ≥40 years, following a standardized protocol. The quality of each test session was evaluated by the spirometer software and an expert reading center. Descriptive statistics were calculated for key maneuver acceptability variables. A logistic regression model identified the predictors of acceptable quality test sessions. RESULTS: About 96% of test sessions met our quality goals for a low back-extrapolated volume (BEV), time to peak flow (PEFT), and end-of-test volume (EOTV). The mean forced expiratory time (FET) was 10.4 s. Ninety percent of the maneuvers with the highest FVC had a forced expiratory time (FET) > 6.8 s. About 90% of test sessions had FEV(1) and FVC which were repeatable within 150 mL. Test quality was slightly better for post-BD test sessions when compared to pre-BD. Independent predictors of adequate test quality included female sex, younger age, higher education, lack of dyspnea, higher pre-BD FEV(1), less BD responsiveness, and study site. CONCLUSIONS: Quality goals for spirometry tests were met about 90% of the time in these population-based samples of adults from several countries.

Impaired lung compliance and DL,CO but no restrictive ventilatory defect in sarcoidosis.

Sarcoidosis is a systemic granulomatous disease with predominant manifestation in the lungs, often presenting as interstitial lung disease. Pulmonary function abnormalities in sarcoidosis include restriction of lung volumes, reduction in diffusing capacity of the lung for carbon monoxide (D(L,CO)), reduced static lung compliance (C(L,s)) and airway obstruction. The aim of the present study was to assess various lung function indices, including C(L,s) and D(L,CO), as markers of functional abnormality in sarcoidosis patients. Results from 830 consecutive patients referred for lung function tests with a diagnosis of sarcoidosis (223 in stage I, 486 in stage II and 121 in stage III) were retreospectively analysed. The mean ± sd age of the patients was 40 ± 11 yrs; 18% were active smokers and 24% were former smokers. Normal total lung capacity was found in 772 (93%) patients. Of these cases, 24.5% had a low C(L,s) and 21.5% had a low D(L,CO). At least one abnormality was observed in 39.3% of these patients, whereas, in restrictive patients, this figure was 88%. Airway obstruction was present in 11.7% of cases. Lung volumes usually remain within the normal range and measurement of either C(L,s) or D(L,CO) often reveal impaired lung function in sarcoidosis patients, even when their lung volumes are still in the normal range; these two measurements provide complementary information.

Comparison of spirometry criteria for the diagnosis of COPD: results from the BOLD study.

Published guidelines recommend spirometry to accurately diagnose chronic obstructive pulmonary disease (COPD). However, even spirometry-based COPD prevalence estimates can vary widely. We compared properties of several spirometry-based COPD definitions using data from the international Burden of Obstructive Lung Disease (BOLD)study. 14 sites recruited population-based samples of adults aged > or =40 yrs. Procedures included standardised questionnaires and post-bronchodilator spirometry. 10,001 individuals provided usable data. Use of the lower limit of normal (LLN) forced expiratory volume in 1 s (FEV(1)) to forced vital capacity (FVC) ratio reduced the age-related increases in COPD prevalence that are seen among healthy never-smokers when using the fixed ratio criterion (FEV(1)/FVC <0.7) recommended by the Global Initiative for Chronic Obstructive Lung Disease. The added requirement of an FEV(1) either <80% predicted or below the LLN further reduced age-related increases and also led to the least site-to-site variability in prevalence estimates after adjusting for potential confounders. Use of the FEV(1)/FEV(6) ratio in place of the FEV(1)/FVC yielded similar prevalence estimates. Use of the FEV(1)/FVC

Can a normal peak expiratory flow exclude severe chronic obstructive pulmonary disease?

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is underdiagnosed. One barrier to diagnosis is the limited availability of spirometry testing, but in adults at risk for COPD, a normal pre-bronchodilator (pre-BD) peak expiratory flow (PEF) may rule out clinically significant COPD. OBJECTIVE: To identify post-BD airway obstruction using data from 13 708 individuals aged >or=40 years from the PLATINO and BOLD studies. METHODS: We evaluated different cut-off points of pre-BD. The PEF was obtained from a diagnostic-quality spirometer (not a mechanical PEF meter). At least one of the following COPD risk factors was present in 77% of the subjects: chronic respiratory symptoms; exposure to tobacco smoke, biomass smoke or dust in the workplace; or a previous diagnosis of asthma, COPD, emphysema or chronic bronchitis. RESULTS: Although the positive predictive value was low as expected, a pre-BD PEF of >or=70% predicted effectively ruled out Stages III and IV COPD of the Global Initiative for Chronic Obstructive Lung Disease. Among those with at least one risk factor, only 12% would require confirmatory spirometry using this criterion. CONCLUSIONS: Adding PEF measurement to a screening questionnaire may rule out severe to very severe COPD without the need for pre- and post-BD spirometry testing. Confirmation is needed from a study using inexpensive PEF meters or pocket spirometers with a staged screening protocol.

A new perspective on concepts of asthma severity and control.

Concepts of asthma severity and control are important in the evaluation of patients and their response to treatment but the terminology is not standardised and the terms are often used interchangeably. This review, arising from the work of an American Thoracic Society/European Respiratory Society Task Force, identifies the need for separate concepts of control and severity, describes their evolution in asthma guidelines and provides a framework for understanding the relationship between current concepts of asthma phenotype, severity and control. "Asthma control" refers to the extent to which the manifestations of asthma have been reduced or removed by treatment. Its assessment should incorporate the dual components of current clinical control (e.g. symptoms, reliever use and lung function) and future risk (e.g. exacerbations and lung function decline). The most clinically useful concept of asthma severity is based on the intensity of treatment required to achieve good asthma control, i.e. severity is assessed during treatment. Severe asthma is defined as the requirement for (not necessarily just prescription or use of) high-intensity treatment. Asthma severity may be influenced by the underlying disease activity and by the patient's phenotype, both of which may be further described using pathological and physiological markers. These markers can also act as surrogate measures for future risk.

Using the lower limit of normal for the FEV1/FVC ratio reduces the misclassification of airway obstruction.

AIM: The prevalence of airway obstruction varies widely with the definition used. OBJECTIVES: To study differences in the prevalence of airway obstruction when applying four international guidelines to three population samples using four regression equations. METHODS: We collected predicted values for forced expiratory volume in 1 s/forced vital capacity (FEV(1)/FVC) and its lower limit of normal (LLN) from the literature. FEV(1)/FVC from 40 646 adults (including 13 136 asymptomatic never smokers) aged 17-90+years were available from American, English and Dutch population based surveys. The prevalence of airway obstruction was determined by the LLN for FEV(1)/FVC, and by using the Global Initiative for Chronic Obstructive Lung Disease (GOLD), American Thoracic Society/European Respiratory Society (ATS/ERS) or British Thoracic Society (BTS) guidelines, initially in the healthy subgroup and then in the entire population. RESULTS: The LLN for FEV(1)/FVC varied between prediction equations (57 available for men and 55 for women), and demonstrated marked negative age dependency. Median age at which the LLN fell below 0.70 in healthy subjects was 42 and 48 years in men and women, respectively. When applying the reference equations (Health Survey for England 1995-1996, National Health and Nutrition Examination Survey (NHANES) III, European Community for Coal and Steel (ECCS)/ERS and a Dutch population study) to the selected population samples, the prevalence of airway obstruction in healthy never smokers aged over 60 years varied for each guideline: 17-45% of men and 7-26% of women for GOLD; 0-18% of men and 0-16% of women for ATS/ERS; and 0-9% of men and 0-11% of women for BTS. GOLD guidelines caused false positive rates of up to 60% when applied to entire populations. CONCLUSIONS: Airway obstruction should be defined by FEV(1)/FVC and FEV(1) being below the LLN using appropriate reference equations.

Assessing the airways.

Spirometry is the best test to detect airway obstruction, categorize the severity of obstructive lung diseases, and objectively measure changes in severity because of disease progression or treatment. However, peak flow may be helpful to rule out moderate to severe airway obstruction and for home monitoring in some patients with asthma.

FEV6 as a surrogate for FVC in detecting airways obstruction and restriction in the workplace.

Compared with measurements of forced vital capacity (FVC), using the forced expiratory volume in six seconds (FEV(6)) reduces test time and frustration. It was hypothesised that using FEV(6) in the workplace setting would result in an acceptably low misclassification rate for detecting airways obstruction and spirometry-defined restriction when compared with using the traditional FVC. Experienced technicians from the National Institute for Occupational Safety and Health performed spirometry using dry rolling-seal spirometers as per American Thoracic Society guidelines in four workplace investigations. Airways obstruction was defined as an FEV(1)/FVC % below the lower limit of normal (LLN) using National Health and Nutrition Examination Survey III reference equations. Restriction was defined as an FVC below the LLN with a normal FEV(1)/FVC %. These "gold standard" definitions were compared with definitions based on FEV(6) (obstruction: FEV(1)/FEV(6) below the LLN; restriction: FEV(6) below the LLN with a normal FEV(1)/FEV(6)). The median (range) age of the 1,139 workers was 37 yrs (18-71 yrs) and 51.4% were male. A significantly high overall agreement was obtained between the two definitions. In conclusion, the current results confirm that forced expiratory volume in six seconds can be used as a surrogate for forced vital capacity in detecting airways obstruction and restriction in workers, although with some misclassification when compared to obtaining American Thoracic Society-acceptable manoeuvres of longer duration.

The diagnosis of asthma in older patients.

Half of the elderly persons with asthma have not been diagnosed, yet their quality of life is substantially lower than others their age. Primary care physicians should, therefore, be encouraged to ask about respiratory symptoms in elderly patients and then perform office spirometry for those with symptoms. Airway obstruction then increases the likelihood of asthma, but the lack of a "significant" acute bronchodilator response is clinically meaningless. Methacholine challenge testing is safe and useful for detecting asthma in patients with normal baseline spirometry. When spirometry shows airway obstruction post-bronchodilator, a normal diffusing capacity (DLCO) test will rule out COPD in current and former smokers. A normal chest X-ray and B-type natriuretic peptide (BNP) will rule out congestive heart failure (CHF) in those with dyspnea.

Respiratory muscle strength and the risk of incident cardiovascular events.

BACKGROUND: Maximal inspiratory pressure (MIP) is a measure of inspiratory muscle strength. The prognostic importance of MIP for cardiovascular events among elderly community dwelling individuals is unknown. Diminished forced vital capacity (FVC) is a risk factor for cardiovascular events which remains largely unexplained. METHODS: MIP was measured at the baseline examination of the Cardiovascular Health Study. Participants had to be free of prevalent congestive heart failure (CHF), myocardial infarction (MI), and stroke. RESULTS: Subjects in the lowest quintile of MIP had a 1.5-fold increased risk of MI (HR 1.48, 95% CI 1.07 to 2.06) and cardiovascular disease (CVD) death (HR 1.54, 95% CI 1.09 to 2.15) after adjustment for non-pulmonary function covariates. There was a potential inverse relationship with stroke (HR 1.36, 95% CI 0.97 to 1.90), but there was little evidence of an association between MIP and CHF (HR 1.22, 95% CI 0.93 to 1.60). The addition of FVC to models attenuated the HR associated with MIP only modestly; similarly, addition of MIP attenuated the HR associated with FVC only modestly. CONCLUSIONS: A reduced MIP is an independent risk factor for MI and CVD death, and a suggestion of an increased risk for stroke. This association with MIP appeared to be mediated through mechanisms other than inflammation.

Lung function and mortality in the United States: data from the First National Health and Nutrition Examination Survey follow up study.

BACKGROUND: A study was undertaken to define the risk of death among a national cohort of US adults both with and without lung disease. METHODS: Participants in the first National Health and Nutrition Examination Survey (NHANES I) followed for up to 22 years were studied. Subjects were classified using a modification of the Global Initiative for Chronic Obstructive Lung Disease criteria for chronic obstructive pulmonary disease (COPD) into the following mutually exclusive categories using the forced expiratory volume in 1 second (FEV(1)), forced vital capacity (FVC), FEV(1)/FVC ratio, and the presence of respiratory symptoms: severe COPD, moderate COPD, mild COPD, respiratory symptoms only, restrictive lung disease, and no lung disease. Proportional hazard models were developed that controlled for age, race, sex, education, smoking status, pack years of smoking, years since quitting smoking, and body mass index. RESULTS: A total of 1301 deaths occurred in the 5542 adults in the cohort. In the adjusted proportional hazards model the presence of severe or moderate COPD was associated with a higher risk of death (hazard ratios (HR) 2.7 and 1.6, 95% confidence intervals (CI) 2.1 to 3.5 and 1.4 to 2.0), as was restrictive lung disease (HR 1.7, 95% CI 1.4 to 2.0). CONCLUSIONS: The presence of both obstructive and restrictive lung disease is a significant predictor of earlier death in long term follow up.