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.

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.

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.

Importance of heart failure with preserved systolic function in patients > or = 65 years of age. CHS Research Group. Cardiovascular Health Study.

Although congestive heart failure (CHF) is a common syndrome among the elderly, there is a relative paucity of population-based data, particularly regarding CHF with normal systolic left ventricular function. A total of 4,842 independent living, community-dwelling subjects aged 66 to 103 years received questionnaires on medical history, family history, personal habits, physical activity, and socioeconomic status, confirmation of pre-existing cardiovascular and cerebrovascular disease, anthropometric measurements, casual seated random-zero blood pressure, forced vital capacity and expiratory volume in 1 second, 12-lead supine electrocardiogram, fasting glucose, creatinine, plasma lipids, carotid artery wall thickness by ultrasonography, and echocardiography-Doppler examinations. Participants with at least 1 confirmed episode of CHF by Cardiovascular Health Study criteria were considered prevalent for CHF. The prevalence of CHF was 8.8% and was associated with increased age, particularly for women, in whom it increased more than twofold from age 65 to 69 years (6.6%) to age > or = 85 years (14%). In multivariate analysis, subjects with CHF were more likely to be older (odds ratio [OR] 1.2 for 5-year difference, men OR 1.1), and more often had a history of myocardial infarction (OR 7.3), atrial fibrillation (OR 3.0), diabetes mellitus (OR 2.1), renal dysfunction (OR 2.0 for creatinine < or = 1.5 mg/ dl), and chronic pulmonary disease (OR 1.8; women only). The echocardiographic correlates of CHF were increased left atrial and ventricular dimensions. Importantly, 55% of subjects with CHF had normal left ventricular systolic function and 80% had either normal or only mildly reduced systolic function. Among subjects with CHF, women had normal systolic function more frequently than men (67% vs 42%; p < 0.001). Thus, CHF is common among community-dwelling elderly. It increases with age and is usually associated with normal systolic LV function, particularly among women. The finding that a large proportion of elderly with CHF have preserved LV systolic function is important because there is a paucity of data to guide management in this dominant subset.

Correlates of daytime sleepiness in 4578 elderly persons: the Cardiovascular Health Study.

OBJECTIVES: To describe the prevalence of self-reported daytime sleepiness in older men and women and to describe their relationships with demographic factors, nocturnal complaints, health status, and cardiovascular diseases (CVD). DESIGN: Cross-sectional survey and clinical exam. SETTING: Participants in the Cardiovascular Health Study, 4578 adults aged 65 and older, recruited from a random sample of non-institutionalized Medicare enrollees in four U.S. communities. MEASURES: Daytime sleepiness measured by the Epworth Sleepiness Scale (ESS), magnetic resonance imaging of the brain (MRI), cognitive function tests, and standardized questionnaires for cardiopulmonary symptoms and diseases, depressive symptoms, social support, activities of daily living, physical activity, and current medications. RESULTS: Approximately 20% of the participants reported that they were "usually sleepy in the daytime". Although elderly black men were less likely to report frequent awakenings than those in the other three race and gender groups, they had significantly higher mean ESS scores. The following were independently associated with higher ESS scores in gender-specific models: non-white race, depression, loud snoring, awakening with dyspnea or snorting, frequent nocturnal awakenings, medications used to treat congestive heart failure, non-use of sleeping pills, a sedentary lifestyle, and limitation of activities of daily living in both men and women; additional correlates included hip circumference and current smoking in men, and hayfever in women. The following were not independently associated with ESS in the models: age, education, use of wine or beer to aid sleep, use of tricyclic antidepressants, long- or short-acting benzodiazepines, asthma, angina, myocardial infarction, congestive heart failure itself, forced vital capacity, social support, cognitive function, or MRI evidence of global brain atrophy or white matter abnormality. CONCLUSIONS: Daytime sleepiness is common in the elderly, probably due to nocturnal disturbances such as frequent awakenings and snoring. The occasional use of sleeping pills for insomnia is associated with reduced daytime sleepiness in the elderly, while the use of medications for congestive heart failure is associated with daytime sleepiness. Surprisingly, anatomic abnormalities such as evidence of previous strokes and brain atrophy (as seen on brain MRI scans) were not associated with daytime sleepiness in these non-institutionalized elderly persons.

Prevalence and correlates of snoring and observed apneas in 5,201 older adults.

The objectives of this study were to describe the prevalence of snoring, observed apneas, and daytime sleepiness in older men and women, and to describe the relationships of these sleep disturbances to health status and cardiovascular diseases (CVD). A cross-sectional design was employed to study sleep problems, CVD, general health, psychosocial factors, and medication use. The subjects were participants in the Cardiovascular Health Study, which included 5,201 adults, aged 65 and older, who were recruited from a random sample of Medicare enrollees in four U.S. communities. Study measures employed were sleep questions, echocardiography, carotid ultrasound, resting electrocardiogram, cognitive function, cardiopulmonary symptoms and diseases, depression, independent activities of daily living (IADLs), and benzodiazepine use. Thirty-three percent of the men and 19% of the women reported loud snoring, which was less frequent in those over age 75. Snoring was positively associated with younger age, marital status, and alcohol use in men, and obesity, diabetes, and arthritis in women. Snoring was not associated, however, with cardiovascular risk factors or clinical CVD in men or women. Observed apneas were reported much less frequently (13% of men and 4% women) than snoring, and they were associated with alcohol use, chronic bronchitis, and marital status in men. Observed apneas were associated with depression and diabetes in women. In both men and women, daytime sleepiness was associated with poor health, advanced age, and IADL limitations. The conclusions of the study were that loud snoring, observed apneas, and daytime sleepiness are not associated cross-sectionally with hypertension or prevalent CVD in elderly persons.

Feasibility of using unattended polysomnography in children for research--report of the Tucson Children's Assessment of Sleep Apnea study (TuCASA).

STUDY OBJECTIVES: The Tucson Children's Assessment of Sleep Apnea study (TuCASA) is designed to investigate the prevalence and correlates of objectively measured sleep-disordered breathing in pre-adolescent children. This paper documents the methods and feasibility of attaining quality unattended polysomnograms in the first 162 TuCASA children recruited. DESIGN: A prospective cohort study projected to enroll 500 children between 5 and 12 years of age who will undergo unattended polysomnography, neurocognitive evaluation, and physiological and anatomical measurements thought to be associated with sleep-disordered breathing. SETTING: Children are recruited through the Tucson Unified School District. Polysomnograms and anthropometric measurements are completed in the child's home. PARTICIPANTS: Of the 157 children enrolled in TuCASA, there were 100 children (64%) between 5-8 years old and 57 children (36%) between the ages of 9 to 12. There were 74 (47%) Hispanic children, and 68 (43%) female participants. INTERVENTIONS: N/A. MEASUREMENTS & RESULTS: Technically acceptable studies were obtained in 157 children (97%). The initial pass rate was 91%, which improved to 97% when 9 children who failed on the first night of recording completed a second study which was acceptable. In 152 studies (97%), greater than 5 hours of interpretable respiratory, electroencephalographic, and oximetry signals were obtained. The poorest signal quality was obtained from the chin electromyogram and from the combination thermister/nasal cannula. Parents reported that 54% of children slept as well as, or better than usual, while 40% reported that their child slept somewhat worse than usual. Only 6% were observed to sleep much worse than usual. Night-to-night variability in key polysomnographic parameters (n=10) showed a high degree of reproducibility on 2 different nights of study using identical protocols in the same child. In 5 children, polysomnograms done in the home were comparable to those recorded in a sleep laboratory. CONCLUSIONS: The high quality of data collected in TuCASA demonstrates that multi-channel polysomnography data can be successfully obtained in children aged 5-12 years in an unattended setting under a research protocol.

Characteristics associated with rapid decline in forced expiratory volume.

Cigarette smoking is known to accelerate decline of pulmonary function; however, the role of other factors is less clear. Characteristics of individuals who experienced rapid decline in forced expiratory volume in 1-sec (FEV1) were examined in 4451 Japanese-American men from the Honolulu Heart Program who were aged 45 to 68 years at baseline (1965-1968) and who produced three acceptable FEV1 measures over a 6-year period. Average annual rates of FEV1 decline were calculated by use of within-person regression and were categorized as rapid (> or = 60 ml/y), moderate (30 to 59 ml/y) or slow (< 30 ml/y). Lifestyle and biologic factors were compared by FEV1 decline categories after adjustment for age. A logistic regression model showed that continued smoking during follow-up, cigarette pack-years, wheezing, coronary heart disease, alcohol intake, and reduced subscapular skinfold were significantly associated with rapid FEV1 decline, after adjustment for age, height, cholesterol, an indicator of Japanese diet, and education. When analyses were restricted to continuous smokers, cigarette pack-years, wheezing, and reduced subscapular skinfold were found to be independent predictors. Among never smokers, lower educational attainment was a predictor of rapid FEV1 decline, and the association involving subscapular skinfold approached significance (P < 0.07). These characteristics may be useful in identifying subgroups of the population who are at increased risk of accelerated decline in pulmonary function and thus would be most likely to benefit from appropriate intervention.

Carbon monoxide diffusing capacity of the lungs determined by single-breath and steady-state exercise methods.

We measured carbon monoxide diffusing capacity of the lungs (DL,CO) by both the resting single-breath (SB) and steady-state (SS) exercise methods in 95 patients referred for pulmonary function testing. A 10-second breath-holding method was used for the SB test. DL,CO (SS) was measured during the last minute of a 3-minute exercise test on a 9-inch step. Results of the two methods showed good agreement, the SB-SS difference averaging -0.70 (SD, 3.39) ml/min per mm Hg. The difference between the two methods was not correlated with other measurements of pulmonary function except minute ventilation during the exercise performed in the DL,CO (SS) procedure. In a separate study of laboratory personnel, the day-to-day variabilities of the two tests were similar (SD, 1.4 ml/min per mm Hg). Alveolar volume obtained by helium dilution during the SB test was comparable to total lung capacity (TLC) estimated by multiple-breath nitrogen washout in patients without severe airway obstruction. In severe airway obstruction, the mean SB alveolar volume was 13.8% less than the TLC by nitrogen washout, a difference that may be useful as an indicator of inefficiency of gas mixing in the lungs. We conclude that the SB and SS exercise methods provide similar estimates of DL,CO in patients referred to a pulmonary function laboratory.

Ambulatory monitoring of peak expiratory flow. Reproducibility and quality control.

Eighty-five children and 230 adults from a population study performed ambulatory peak flow readings three times a day for 1 to 2 weeks following a home visit. Three peak expiratory flow (PEF) readings were reported for each of 5,809 test sessions. Within each test session, the third maneuver most frequently (40% of the time) gave the highest PEF reading. This did not vary throughout the day. In subgroups of children and women with a history of asthma or asthma symptoms (hereinafter referred to as "asthma"), the first maneuver during the evening test sessions more frequently gave the highest readings. However, maneuver-induced bronchospasm occurred during less than 5% of the test sessions in both subjects with asthma and in other subjects. The within test session PEF reproducibility was good: overall, the highest and second highest reading matched within one division (10 L/min) 73% of the time and within 30 L/min (9% of the reading) 95% of the time. The best reproducibility was noted after the first two days of testing, during evening and bedtime test sessions (vs morning), and in girls and men. In the group with at least 2 weeks of testing, the coefficient of repeatability (CR) for the week-to-week PEF lability index was 10% for healthy adults and 17% for healthy children. As expected, repeatability was not as good for adults with asthma (CR = 17%) and children with asthma (CR = 28%).

Spirometry reference values for healthy elderly blacks. The Cardiovascular Health Study Research Group.

Pulmonary function was assessed by spirometry in 497 black and 2,980 white ambulatory elderly male and female participants of the Cardiovascular Health Study. The quality assurance program prompted technicians to exceed American Thoracic Society recommendations for spirometry. A "healthy" subgroup of 235 black and 1,227 white participants age 65 years and older was identified by excluding current and former smoker, and those with self-reported asthma or emphysema, congestive heart failure, and poor-quality results of spirometry tests, since those factors were associated with a lower FEV1. Reference equations and normal ranges for elderly blacks for measurements of FEV1, FVC, and the FEV1/FVC ratio were then determined from the healthy group. These elderly blacks had an FVC about 6% lower than elderly whites, even after correcting for standing height, sitting height (trunk length), and age. The popular use of spirometry reference values from studies of middle-aged white subjects by applying a 12% race correction factor for black patients appears to overestimate predicted values.

Prevalence and correlates of respiratory symptoms and disease in the elderly. Cardiovascular Health Study.

Spirometry was performed by 5,201 elderly participants of the Cardiovascular Health Study during their baseline examination and a subset of the ATS/DLD-78 respiratory questionnaire was administered by trained interviewers. In never smokers (46 percent of the cohort), the overall prevalence of chronic cough was 9 percent, chronic phlegm was 13 percent, attacks of wheezing with dyspnea were 8 percent, and grade 3 dyspnea on exertion was 10 percent. The prevalence of lung disease in current smokers (12 percent of the cohort) was 8/7 percent (men/women) with chronic bronchitis and 14/5 percent with emphysema. Overall, 6 percent reported asthma (a physician-confirmed history) and 12 percent reported hay fever. Using a logistic regression model, attacks of wheezing with dyspnea were strongly associated with a lower FEV1, coronary heart disease, heart failure, and a large waist size (in participants without a diagnosis of asthma, chronic bronchitis, or emphysema). Undiagnosed airways obstruction was twice as likely in women and those with lower income, and was associated with current and former smoking, pack-years of smoking, and chronic cough. Dyspnea on exertion (DOE) was three times or more likely if a participant reported heart failure, coronary heart disease, or emphysema; and much more likely if their FEV1 or FVC was substantially reduced. Dyspnea on exertion was also positively associated with older age, chronic bronchitis or asthma, a larger waist or hip size, pack-years of smoking, and less education. We conclude that DOE and attacks of wheezing with dyspnea are commonly associated with cardiovascular disease and a low FEV1 in those over 65 years and that airways obstruction frequently remains undiagnosed in the elderly.

Spirometry and maximal respiratory pressure references from healthy Minnesota 65- to 85-year-old women and men.

OBJECTIVE: To obtain spirometry and maximal respiratory pressure (MRP) reference values for elderly persons. DESIGN: Survey. SETTING: General community. PARTICIPANTS: Four hundred seventy-one healthy ambulatory white women and men age 65+ years. METHODS: A stringent spirometry quality assurance program exceeded American Thoracic Society recommendations. A "healthy" subgroup of 176 women and 112 men between the ages of 65- and 85 years were identified by excluding those with conditions that negatively influenced FEV1 in a multiple regression analysis. Reference equations and normal ranges for FEV1, FVC, FEF25-75%, peak flow, and maximal inspiratory and expiratory pressures (MRPs) were determined from the healthy group with good quality maneuvers. RESULTS: Less than 10% of the subjects were unable to perform three acceptable spirometry maneuvers and ten MRP maneuvers. When the age and height corrected FEV1s from this group were compared with other spirometry reference studies, mean values from the women were nearly identical to those from Morris, while these men had substantially lower FEV1 values (by 0.3- to 0.5L) than elderly men in Crapo's study. Mean peak flow was over 20% higher when compared with previous studies, suggesting greater initial expiratory effort by our subjects. The maximal inspiratory pressure (MIP) values were about 20% higher than those reported by the Cardiovascular Health Study, perhaps because five MIP maneuvers were always performed. CONCLUSION: Spirometry and MRP reference values used for elderly patients should come from population studies using similar techniques and with large numbers of subjects over age 65 years.

Office spirometry for lung health assessment in adults: A consensus statement from the National Lung Health Education Program.

COPD is easily detected in its preclinical phase using spirometry, and successful smoking cessation (a cost-effective intervention) prevents further disease progression. This consensus statement recommends the widespread use of office spirometry by primary-care providers for patients >/= 45 years old who smoke cigarettes. Discussion of the spirometry results with current smokers should be accompanied by strong advice to quit smoking and referral to local smoking cessation resources. Spirometry also is recommended for patients with respiratory symptoms such as chronic cough, episodic wheezing, and exertional dyspnea in order to detect airways obstruction due to asthma or COPD. Although diagnostic-quality spirometry may be used to detect COPD, we recommend the development, validation, and implementation of a new type of spirometry-office spirometry-for this purpose in the primary-care setting. In order to encourage the widespread use of office spirometers, their specifications differ somewhat from those for diagnostic spirometers, allowing lower instrument cost, smaller size, less effort to perform the test, improved ease of calibration checks, and an improved quality-assurance program.

Underdiagnosis and undertreatment of asthma in the elderly. Cardiovascular Health Study Research Group.

OBJECTIVE: To describe the clinical correlates of asthma in a community-based sample of elderly persons. PARTICIPANTS: A community sample of 4,581 persons > or = 65 years old from the Cardiovascular Health Study. MEASUREMENTS: Standardized respiratory, sleep, and quality-of-life (QOL) questions, a medication inventory, spirometry, and ambulatory peak flow. RESULTS: Four percent of the participants reported a current diagnosis of asthma (definite asthma), while another 4% reported at least one attack of wheezing accompanied by chest tightness or dyspnea during the previous 12 months (probable asthma). Smokers and those with congestive heart failure were excluded from the subsequent analyses, leaving 2,527 participants. Of those who had definite asthma, 40% were taking a sympathomimetic bronchodilator, 30% inhaled corticosteroids, 21% theophylline, and 18% oral corticosteroids; 39% were taking no asthma medications. The participants with definite or probable asthma were much more likely than the others to have a family history of asthma, childhood respiratory problems, a history of workplace exposures, dyspnea on exertion, hay fever, chronic bronchitis, nocturnal symptoms, and daytime sleepiness. They were also more likely to report poor general health, symptoms of depression, and limitation of activities of daily living. There was little difference in the morbidity and QOL of participants with recent asthma-like symptoms who had received the diagnosis of asthma versus those who had not. CONCLUSIONS: Asthma in elderly persons is associated with a lower QOL and considerable morbidity when compared with those who do not have asthma symptoms. Asthma is underdiagnosed in this group and is often associated with allergic triggers; inhaled corticosteroids are underutilized.

Lung volumes in 4,774 patients with obstructive lung disease.

STUDY OBJECTIVES: To determine the correlates of static lung volumes in patients with airways obstruction, and to determine if static lung volumes differ between asthma and COPD. PATIENTS AND METHODS: We examined the data from all of the adult patients (mean age of 69) who were referred to a pulmonary function laboratory from January 1990 through July 1994 with an FEV1/FVC ratio of < 0.70 and tested using a body plethysmograph. Correlates were determined using regression analysis. MEASUREMENTS AND RESULTS: Of the 4,774 patients observed with evidence of airways obstruction, 61% were men. Self-reported diagnoses included asthma, 19%; emphysema or COPD, 23%; chronic bronchitis, 1.5%; and alpha1-antiprotease deficiency, 0.6%. Fifty-six percent of the patients did not report a respiratory disease. The degree of hyperinflation, as determined by the residual volume (RV)/total lung capacity (TLC) ratio, or the RV % predicted (but not the TLC % predicted), was strongly associated with the degree of airways obstruction (the FEV1 % predicted). Patients with moderate to severe airways obstruction and high RV and TLC levels were more likely to have COPD than asthma. Of the 1,872 patients with a reduced vital capacity determined by spirometry testing, 87% had hyperinflation as defined by the RV/TLC, and 9.5% had a low TLC (with less severe airways obstruction). CONCLUSION: In patients found to have airways obstruction by spirometry, the additional measurement of static lung volumes added little to the clinical interpretation.