Risk factors for prevalence of and mortality related to restriction on spirometry: findings from the First National Health and Nutrition Examination Survey and follow-up.

OBJECTIVE: To define risk factors for both restriction on spirometry and subsequent mortality in a national cohort of US adults. METHODS: Participants in the First National Health and Nutrition Examination Survey (NHANES I) were followed for up to 22 years. Subjects were classified using the forced expiratory volume in one second (FEV1), the forced vital capacity (FVC), and the FEV1/FVC ratio into subgroups with and without restriction on spirometry. Regression models were developed to determine risk factors for restriction on spirometry and death. RESULTS: Our final cohort consisted of 4320 subjects, of whom 481 (10.3 weighted %) had restriction on spirometry. The largest risk factors for restriction on spirometry were a cardiothoracic ratio of >55% (OR 4.3, 95%CI 3.1-5.9), race other than black or white (OR 3.7, 95%CI 1.8-7.8), and a history of stroke or paralysis (OR 1.8, 95%CI 1.1-2.9). The overall mortality rate was increased in subjects with restriction on spirometry (25.7 vs. 10.3 deaths per 1000 person-years). CONCLUSIONS: Restriction on spirometry is associated with comorbid disease and increased mortality, and is present in a significant proportion of the population.     

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.     

Impact of bronchodilator use on the prevalence of COPD in population-based samples

The aim of this study was to describe the impact of using bronchodilators on the prevalence of Chronic Obstructive Pulmonary Disease in a population-based survey (Platino study). A cluster sampling of subjects 40 years of age or older, representative of the metropolitan areas of 5 Latin American cities (Sao Paulo, Mexico, Montevideo, Santiago and Caracas) was chosen. Spirometry according to ATS standards was done before and after inhalation of 200 micrograms of salbutamol in 5183 subjects. Prevalences of airflow obstruction were estimated using different criteria, in tests done before and after bronchodilator use, and with reference values for pre- or post-bronchodilator use. Bronchodilator testing reduced the overall prevalence of FEV(1)/FVC% < 0.70 from 21.7% to 14% (35%). In the group with FEV(1)/FVC < 0.70 after bronchodilator use, 21% were asymptomatic from the respiratory point of view, and lacked significant adverse exposures. Subjects below the 5th percentile for FEV(1)/FVC and FEV(1)/FEV(6) were fewer than those with FEV(1)/FVC < 0.70, especially among the elderly. More subjects are below the 5th percentile of FEV(1)/FVC and FEV(1)/FEV(6) using reference values for tests after bronchodilator use than using the reference values determined without bronchodilator testing. Testing after bronchodilator use reduces the prevalence of airflow obstruction from 32 to 39% depending on the definition used. In addition, the subjects who were still obstructed after bronchodilator use were the ones who showed more respiratory symptoms and exposure to tobacco and other smokes and dusts, than subjects with reversible obstruction, suggesting an increased specificity for COPD.     

Bronchodilator reversibility, exercise performance and breathlessness in stable chronic obstructive pulmonary disease.

Partial bronchodilator reversibility can be demonstrated in many patients with stable chronic obstructive pulmonary disease (COPD), but its relevance to exercise capacity and symptoms is uncertain. Previous data suggest that anticholinergic bronchodilators do not improve exercise tolerance in such patients. We studied 32 patients with stable COPD, mean age 65 yrs, in a double-blind, placebo-controlled, cross-over trial of the inhaled anticholinergic drug, oxitropium bromide. From the within and between day placebo spirometry, we derived the spontaneous variation in forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) of this population (FEV1 140 ml; FVC 390 ml) and considered responses beyond this to be significant. Oxitropium bromide increased baseline FEV1 from 0.70 (0.28) l (mean (SD)) to 0.88 (0.36) l. The 6 min walking distance increased by 7% compared with placebo, whilst resting breathlessness scores fell from 2.0 to 1.23 at rest and 4.09 to 3.28 at the end of exercise after the active drug. Improvements in walking distances and symptoms were unrelated to changes in either FEV1 or FVC, indicating that routine reversibility testing is not a good predictor of symptomatic benefit in these patients.     

Reversibility test in the early stages of bronchial asthma.

In the early stages of bronchial asthma, it is frequent to find subjects with a positive history and an FEV1 or FEV1/FVC > 80% of the predicted value. This study investigated if the test of reversibility showed a reversible airway obstruction (RAO) in 291 subjects with the above clinical and functional features. Forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and expiratory flows (PEF, MEF50, FEF(25-75)) were registered before and 20 minutes after salbutamol administration (200 mcg by MDI). Of 291 subjects, FEV1 increased in 73 (25%) after bronchodilator > or = 12% compared to baseline; the number of subjects with a > or = 35% increase in MEF50 or FEF(25-75) were similar in terms of percentage (respectively, 29.2% and 29%), whereas those with increases in FVC (> or = 12%) and in PEF (> or = 15%) were significantly lower (respectively, 2.7% and 12.3%). The percentage of subjects with RAO (FEV1 increase after bronchodilator > or = 12%) was lower (12%) in the subgroup (108 subjects), with an MEF50 > or = 70% of the value predicted at the baseline assessment, and higher (36%) in the subjects of the subgroup (183 subjects) with an MEF50 < 70%. In conclusion, it is advisable to carry out reversibility tests in all subjects with symptoms indicative of asthma even if their functional tests are "normal" because in a considerable number of cases the RAO was found to confirm the suspected diagnosis and provided a more reliable classification of the disease.     

Chronic obstructive pulmonary disease is missed in asthmatics in specialty care in Trinidad, West Indies.

SETTING: Underdiagnosis of chronic obstructive pulmonary disease (COPD) in asthmatics attending specialty care in Trinidad, West Indies. OBJECTIVE: To determine the prevalence of COPD in diagnosed asthmatics receiving specialty respiratory care. DESIGN: In a cross-sectional study, 258 asthmatics were screened for lung function measures to examine forced expiratory volume after 1 second (FEV1), forced vital capacity (FVC) and post-bronchodilator FEV1/FVC (COPD was defined as FEV1/FVC < 70%). RESULTS: Of 165 patients evaluated (response rate 64.0%), 53 (32.1%, 95%CI 25.0-39.2) had a study diagnosis of COPD and a mean FEV1/FVC of 60.12 +/- 1.2. Proportionally, more males had COPD (50.9%) than asthma (24.1%, P < 0.001). Patients with COPD were 10 years older than asthmatics (P < 0.001). Persons with asthma who smoked were more likely to have COPD (56.0%) (OR 3.26, 95%CI 1.36-7.80, P = 0.006). In both sexes, FEV1/FVC was lower among older people (P < 0.001), with a greater effect (OR 2.75, 95%CI 1.00-7.56, P < 0.01) seen among men in this cross-sectional study. CONCLUSIONS: One third of diagnosed asthmatics in specialty care also have COPD. Lung function was lower among older persons. Early spirometric evaluation of elderly asthmatics who smoke can determine the presence of COPD and facilitate appropriate management.     

Prevalence of Airflow Obstruction as Measured by Spirometry,in Rural Southern Indian Adults

Abstract

Rural population-based estimates of airflow obstruction based on spirometry are unavailable from southern India. This study assessed the prevalence of spirometry-defined airflow obstruction in Vellore, Tamil Nadu.

A cross sectional survey was done in nine villages, among adults aged ≥30?years, where previous cardiovascular surveys had been conducted (1994, 2011). Population proportional to size sampling was used to select 20 clusters, with sampling from all streets proportional to the number of households. One person randomly selected per household was interviewed for symptoms and risk factors. A respiratory therapist performed pre and post bronchodilator spirometry on all, following American Thoracic Society criteria. Airflow obstruction was defined as pre-bronchodilator Forced Expiratory Volume 1?s/Forced Vital Capacity (FEV1/FVC)?<?Lower Limit of Normal (LLN, derived from local prediction equations) and compared to other criteria.

Of 1015 participants, 787 completed technically acceptable spirometry. The prevalence of airflow obstruction was 9.0% (95% CI: 5.8%–9.6%, 71). Fixed obstruction (post bronchodilator FEV1/FVC?<?LLN) was 4.6% (95% CI: 3.1%–6.1%, 36), and 4.1% (95% CI: 2.7%–5.5%, 32) using post bronchodilator FEV1/FVC?<?70%. The GOLD criteria missed 56% (40) of those with airflow obstruction, of which 87.5% were females. Although 63.4% with airflow obstruction had moderate to severe disease, 82.2% were not on treatment and only 48.9% reported symptoms in the previous year.

This study estimates prevalence of airflow obstruction based on spirometry in rural southern India. Despite significant impairment on spirometry, majority were undiagnosed, and half did not report symptoms.     

Predictors of disease severity in children with asthma in Hartford, Connecticut

Childhood asthma is a major public health problem in the United States, particularly among minority populations. The aim of our study was to examine the relationship among ethnicity, allergen sensitization, spirometric measures, and asthma severity in children with mild to severe asthma who received their medical care in Hartford, Connecticut. Four hundred thirty-eight children aged 4-18 years who were enrolled in an asthma care program (Easy Breathing) in Hartford and who were referred for spirometry and allergy skin testing participated in this cross-sectional study. Risk factors for increased asthma severity as defined by National Asthma Education and Prevention Program (NAEPP) guidelines were determined using multinomial logistic regression. Of 438 children, 383 (87.4%) had mild to moderate asthma, and 292 (66.7%) had at least one positive skin test to allergens. Forced expiratory volume in 1 sec/forced vital capacity (FEV1/FVC) was significantly decreased in children with severe vs. mild asthma (80.7 vs. 87.3, respectively). In a multivariate analysis, predictors of severe asthma included African-American ethnicity (odds ratio (OR)=3.70, 95% confidence interval (CI)=1.10-12.42), Puerto Rican ethnicity (OR=3.55, 95% CI=1.18-10.67), sensitization to cockroach allergen (OR=4.34, 95% CI=1.73-10.86), and decreased FEV1/FVC (OR for every 1% decrease in FEV1/FVC=1.06, 95% CI=1.02-1.11). In conclusion, among children with asthma in Hartford and its surrounding communities, predictors of disease severity included African-American ethnicity, Puerto Rican ethnicity, sensitization to cockroach allergen, and decreased FEV1/FVC. Our findings suggest that FEV1/FVC is a useful indicator of asthma severity in children.     

Post-bronchodilator spirometry reference values in adults and implications for disease management

RATIONALE: International guidelines promote the use of post-bronchodilator spirometry values in the definition and severity classification of chronic obstructive pulmonary disease. However, post-bronchodilator reference values have not yet been developed. OBJECTIVES: To derive reference values for post-bronchodilator forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and FEV1/FVC, and to compare these reference values with locally derived and existing pre-bronchodilator reference values. METHODS: Based on a random sample of a general adult population, 2,235 subjects (70% of invited subjects) performed spirometry with reversibility testing. A reference population of healthy never-smokers constituted 23% of the study population (n=515). Reference values for median and lower-limit-of-normal pre- and post-bronchodilator lung function and bronchodilator response were modeled using quantile regression analyses. MAIN RESULTS: The reference population had equal proportions of men and women in the age range 26-82 yr. Both FEV1 and FVC decreased with age and increased with height. FEV1/FVC decreased with age, although this trend was not statistically significant for men after bronchodilatation. Linear models gave the best overall fit. Lower-limit-of-normal post-bronchodilator FEV1/FVC exceeded 0.7 for both sexes. Post-bronchodilator prediction equations gave higher predicted FEV1 and FEV1/FVC than both locally derived and existing pre-bronchodilator equations. The bronchodilator response decreased with age. CONCLUSIONS: The present study is the first to develop reference values for post-bronchodilator lung function. Post-bronchodilator prediction equations can facilitate better management of patients with chronic obstructive pulmonary disease by avoiding falsely high FEV1% predicted with a subsequent underestimation of disease severity.     

Comparison between specified percentage and fifth percentile criteria for spirometry interpretation in Thai patients

OBJECTIVES: The present study was conducted to determine the degree of agreement between the interpretation of spirometry using a specified percentage of predicted value (SPC) and the fifth percentile (FPC) as the cut off between normal and abnormal. METHODOLOGY: Spirometric values were collected for 1754 subjects attending the respiratory service at Siriraj Hospital between February 2000 and April 2001. These values included forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), FEV1/FVC, maximal mid-expiratory flow (FEF25-75%) and peak expiratory flow (PEF). A comparison of results between SPC and FPC was performed. The SPC cut-off values for FVC, FEV1, FEV1/FVC, FEF25-75% and PEF were 80% predicted, 80% predicted, 70%, 65% predicted and 80% predicted, respectively. The FPC cut-off values were calculated from reference equations for the Thai population. Inter-rater agreement was calculated as the kappa score. RESULTS: High kappa scores were obtained for FVC (0.84), FEV1 (0.88) and FEF25-75% (0.80). However, poor agreement was found for FEV1/FVC (0.72) and PEF (0.61). When the cut-off values for SPC were modified to 90% of predicted values for FEV1/FVC and to 65% of predicted values for PEF, agreement was substantially improved to 0.92 and 0.89, respectively. CONCLUSIONS: Interpretation by SPC using cut-off values of 80% predicted for FVC and FEV1 and 65% predicted for FEF25-75% resulted in good agreement with FPC. However, the SPC cut-off values for FEV1/FVC and PEF should be modified to 90% predicted and 65% predicted, respectively.     

The prognosis of respiratory failure in patients with tuberculous destroyed lung.

SETTING: The medical intensive care unit of a tertiary referral hospital. OBJECTIVE: To determine the prognosis of patients whose lungs are damaged by previous and/or present tuberculosis infection and who have subsequently been presented with acute respiratory failure requiring mechanical ventilation. DESIGN: A consecutive series of 38 patient cases with retrospective data analysis. RESULTS: Pulmonary function test results for tests performed within the previous year were made available in 21 of the 38 cases (55%). These showed a mean (+/- SD) forced vital capacity (FVC) of 1.52 +/- 0.46 L (41.0 +/- 14.5% predicted), a forced expiratory volume/second (FEV1) of 0.77 +/- 0.18 L (29.3 +/- 13.6% predicted), and an FEV1/FVC ratio of 55.1 +/- 16.2%. The acid-fast bacilli (AFB) positive group had a significantly higher mortality and more severe lung destruction when compared with the AFB-negative group. Patients with positive AFB were significantly more hypocapnic than those with negative AFB (6.4 +/- 2.7 vs. 9.3 +/- 3.9 kPa, P = 0.020). In multivariate analysis, the level of PaCO2 on admission was identified as the only significant prognostic index (OR 0.76, 95%CI 0.60-0.96). CONCLUSION: Patients with positive AFB smears or cultures may have higher mortality rates than those with negative AFB in the tuberculosis destroyed lung patients with acute respiratory failure. A higher PaCO2 measurement could indicate a better survival rate in this group of patients.     

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.     

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.     

Airway hyperreactivity detected by methacholine challenge in children with sickle cell disease

Recent studies have emphasized the presence of airway hyperreactivity (AHR) in children with sickle cell disease (SCD). However, various tests for the detection of AHR have yielded distinctly different results in these patients. This study identified AHR via a methacholine challenge test (MCT) in a group of children with SCD (31 patients; age range, 6-16 years). The results of pulmonary function tests (PFTs) in patients with SCD and age-matched controls (30 healthy children) were investigated and compared. A positive methacholine challenge result was noted in 25 patients (77.5%). We found that when compared with controls, the children with SCD had lower forced vital capacity (FVC) and forced expiratory volume in 1 sec (FEV(1)) and that both their forced expiratory flow at 25-75% of the FVC (FEF(25-75)) and their FEV(1)/FVC ratio were not statistically significantly different from those of the controls. The statistically significant differences remained after treatment with a bronchodilator agent, but the changes in the FVC, FEV(1), and FEF(25-75) in response to bronchodilator treatment did not differ with statistical significance between the two groups. There was a negative correlation between the number of ACS attacks and the percent predicted of the FEV(1) and the FEV(1)/FVC ratio. We found that the MCT reveals a high incidence of AHR in patients with SCD, regardless of whether those individuals have ACS.     

Reversing acute bronchoconstriction in asthma: the effect of bronchodilator tolerance after treatment with formoterol.

Continuous treatment with a short-acting beta2-agonist can lead to reduced bronchodilator responsiveness during acute bronchoconstriction. This study evaluated bronchodilator tolerance to salbutamol following regular treatment with a long-acting beta2-agonist, formoterol. The modifying effect of intravenous corticosteroid was also studied. Ten asthmatic subjects (using inhaled steroids) participated in a randomised, double-blind, placebo-controlled, cross-over study. Formoterol 12 microg b.i.d. or matching placebo was given for 10-14 days with >2 weeks washout. Following each treatment, patients underwent a methacholine challenge to induce a fall in forced expired volume in one second (FEV1) of at least 20%, then salbutamol 100 microg, 100 microg, and 200 microg was inhaled via a spacer at 5 min intervals, with a further 400 microg at 45 min. After a third single-blind formoterol treatment period, hydrocortisone 200 mg was given intravenously prior to salbutamol. Dose-response curves for change in FEV1 with salbutamol were compared using analysis of covariance to take account of methacholine-induced changes in spirometry. Regular formoterol resulted in a significantly lower FEV1 after salbutamol at each time point compared to placebo (p<0.01). The area under the curves (AUCs) for 15 (AUC0-15) and 45 (AUC0-45) min were 28.8% and 29.5% lower following formoterol treatment (p<0.001). Pretreatment with hydrocortisone had no significant modifying effect within 2 h of administration. It is concluded that significant tolerance to the bronchodilator effects of inhaled salbutamol occurs 36 h after stopping the regular administration of formoterol. This bronchodilator tolerance is evident in circumstances of acute bronchconstriction.     

Assessment of emphysema in COPD: a functional and radiologic study

OBJECTIVES: A combination of functional measurements reflecting a decrease in maximum flow, a degree of lung hyperinflation, the relationship between maximum inspiratory and expiratory flows, bronchodilator response, and diffusing capacity of the lung for carbon monoxide (DLCO) was used to quantify the extent of emphysema, as assessed by high-resolution CT (HRCT) scanning. DESIGN: Forced inspiratory and expiratory spirometry, lung volumes, reversibility test, and single-breath diffusing capacity were assessed before and after inhaling albuterol, 200 microg. Relationships between lung function variables and emphysema extent, as determined by HRCT scanning, were tested by univariate and multivariate analyses. SUBJECTS: Thirty-nine COPD outpatients with moderate-to-severe obstruction. MEASUREMENTS AND RESULTS: Emphysema extent, as assessed by HRCT scanning, ranged from 18 to 70%. All of the lung function parameters that were studied, except for the change in FEV1 percent predicted after salbutamol inhalation, correlated significantly with the extent of emphysema (r2 range, 0.19 to 0.44). Functional residual capacity, forced expiratory flow at 50% of FVC/forced inspiratory flow at 50% of FVC, DLCO/alveolar volume ratio, and bronchodilator-induced change in FEV1/FVC ratio were the only variables retained by stepwise multiple regression analysis. The multiple regression model explained 71% of the variability of emphysema extent measured by HRCT scanning. CONCLUSIONS: The combination of lung function measurements reflecting lung hyperinflation, bronchial collapsibility, lung diffusing capacity, and bronchodilator response provides a good estimate of the extent of emphysema, as evaluated by HRCT scanning. These data suggest that pulmonary function tests are useful in assessing and monitoring parenchymal damage in COPD patients.     

Comparison of tiotropium once daily, formoterol twice daily and both combined once daily in patients with COPD.

This study compared the bronchodilator effects of tiotropium, formoterol and both combined in chronic obstructive pulmonary disease (COPD). A total of 71 COPD patients (mean forced expiratory volume in one second (FEV1) 37% predicted) participated in a randomised, double-blind, three-way, crossover study and received tiotropium 18 microg q.d., formoterol 12 microg b.i.d. or both combined q.d. for three 6-week periods. The end-points were 24-h spirometry (FEV1, forced vital capacity (FVC)) at the end of each treatment, rescue salbutamol and safety. Compared with baseline (FEV1 prior to the first dose in the first period), tiotropium produced a significantly greater improvement in average daytime FEV1 (0-12 h) than formoterol (127 versus 86 mL), while average night-time FEV1 (12-24 h) was not different (tiotropium 43 mL, formoterol 38 mL). The most pronounced effects were provided by combination therapy (daytime 234 mL, night-time 86 mL); both differed significantly from single-agent therapies. Changes in FVC mirrored the FEV1 results. Compared with both single agents, daytime salbutamol use was significantly lower during combination therapy (tiotropium plus formoterol 1.81 puffs.day(-1), tiotropium 2.41 puffs x day(-1), formoterol 2.37 puffs x day(-1)). All treatments were well tolerated. In conclusion, in chronic obstructive pulmonary disease patients, tiotropium q.d. achieved a greater improvement in daytime and comparable improvement in night-time lung function compared with formoterol b.i.d. A combination of both drugs q.d. was most effective and provided an additive effect throughout the 24-h dosing interval.     

Obstructive and restrictive spirometric patterns: fixed cut-offs for FEV1/FEV6 and FEV6.

The purpose of this study was to determine fixed cut-off points for forced expiratory volume in one second (FEV(1))/FEV(6) and FEV(6) as an alternative for FEV(1)/forced vital capacity (FVC) and FVC in the detection of obstructive and restrictive spirometric patterns, respectively. For the study, a total of 11,676 spirometric examinations, which took place on Caucasian subjects aged between 20-80 yrs, were analysed. Receiver-operator characteristic curves were used to determine the FEV(1)/FEV(6) ratio and FEV(6) value that corresponded to the optimal combination of sensitivity and specificity, compared with the commonly used fixed cut-off term for FEV(1)/FVC and FVC. The data from the current study indicate that FEV(1)/ FEV(6) <73% and FEV(6) <82% predicted can be used as a valid alternative for the FEV(1)/FVC <70% and FVC <80% pred cut-off points for the detection of obstruction and restriction, respectively. The statistical analysis demonstrated very good, overall, agreement between the two categorisation schemes. For the spirometric diagnosis of airway obstruction (prevalence of 45.9%), FEV(1)/FEV(6) sensitivity and specificity were 94.4 and 93.3%, respectively; the positive and negative predictive values were 92.2 and 95.2%, respectively. For the spirometric detection of a restrictive pattern (prevalence of 14.9%), FEV(6) sensitivity and specificity were 95.9 and 98.6%, respectively; the positive and negative predictive values were 92.2 and 99.3%, respectively. This study demonstrates that forced expiratory volume in one second/forced expiratory volume in six seconds <73% and forced expiratory volume in six seconds <82% predicted, can be used as valid alternatives to forced expiratory volume in one second/forced vital capacity <70% and forced vital capacity <80% predicted, as fixed cut-off terms for the detection of an obstructive or restrictive spirometric pattern in adults.     

Effect of tobacco smoking, respiratory symptoms and asthma on spirometry among adults attending a check-up clinic in Mexico City

OBJECTIVE: To evaluate the effect of tobacco smoking, respiratory symptoms, and asthma on lung function among Mexican adults who were evaluated during a medical exam in a private health clinic. MATERIAL AND METHODS: Reference prediction equations were generated for spirometry parameters [forced vital capacity (FVC), forced expired volume in one second (FEV1) and FEV1/FVC] based on multiple linear regression models. The effect of tobacco smoking, respiratory symptoms and asthma on these equations were explored. RESULTS: Spirometry tests were performed on 919 subjects from 14 to 86 years of age.Asthma decreased FVC and FEV1 in men with a R2 change <1%. Respiratory symptoms decreased the FEV1/FVC ratio in both sexes.Tobacco smoking was associated with a significant reduction in FEV in women. CONCLUSIONS: Asthma lightly reduced lung function in males while tobacco smoking decreased FEV, particularly in females.     

Bronchodilator response to adrenergic beta2-agonists: relationship to symptoms in an adult community

BACKGROUND: Wheeze and chest tightness has traditionally been associated with enhanced bronchial responsiveness. However, no community studies are available on the associations between bronchodilator response and respiratory symptoms among adults. AIM: To examine how respiratory symptoms predict bronchodilator response. METHODS: An age and gender stratified random sample of all adults aged 47-48 and 71-73 years in Bergen, Norway, were invited. The 3506 participants (69%) filled in questionnaires including nine symptoms and performed bronchodilator reversibility tests. Subjects without current anti-asthmatic medication performing acceptable reversibility tests were included in the analyses (n=3088). RESULTS: A reversibility with FEV(1) increase 12% and 200 ml was obtained in 2% of middle-aged and 4% of elderly subjects (p=0.001). In multiple linear regression analysis bronchodilatation was positively associated with wheezing without cold (FEV(1) increase of 1.5%, 95% CI: (0.9, 2.2)% in all participants and 31 ml, 95% CI: (1, 61)ml in men only) and dyspnoea climbing two flights of stairs (0.9%, 95% CI: (0.5,1.4)% and 12 ml, 95% CI: (1,23)ml). Chronic cough predicted the response negatively (-0.7%, 95% CI: (-1.3,-0.1)% and -17 ml, 95% CI: (-32,-2)ml). In multiple logistic regression analysis morning cough predicted an FEV(1) increase 12% and 200 ml (OR: 1.8, 95% CI: (1.1,2.8)). CONCLUSIONS: A small fraction of adults in a general population has bronchodilatation after salbutamol inhalation. "Wheezing without cold", "dyspnoea climbing two flights of stairs", and "morning cough" predict an increased bronchodilator response among subjects without current anti-asthmatic medications.