Increasing COPD awareness.

Early diagnosis and smoking cessation are the only available methods to stop the progression of chronic obstructive pulmonary disease (COPD). The aim of this study was to evaluate the effects of early detection of airflow limitation (AL) in a population with high risk for COPD, using spirometric screening. Smokers aged 40 yrs with a smoking history of 10 pack-yrs were invited to visit a local outpatient chest clinic for simple spirometry (forced expiratory volume in one second (FEV1) and forced vital capacity (FVC)). Smoking history was recorded, followed by smoking cessation advice relating the results of spirometry to the smoking behaviour. Subjects who did not fulfil the above criteria (younger and/or nonsmokers) were also screened. A total 110,355 subjects were investigated; they were aged 53.5+/-11.5 yrs and 58.2% were males. Of the total amount of subjects, 64% were current smokers, 25.1% were former smokers and 10.9% were lifelong nonsmokers. Spirometry tests were within normal values for 70.3%, and 20.3% showed signs of AL: this was mild in 7.6%, moderate in 6.7% and severe in 5.9%. The remaining 8.3% of subjects presented with a restrictive pattern of ventilatory impairment. Airflow limitation was found in 23% of smokers aged 40 yrs with a history of 10 pack-yrs. This study concluded that large-scale voluntary spirometry screening of the population with high risk for COPD detects a large number of subjects with AL.     

Early detection of COPD in a high-risk population using spirometric screening

STUDY OBJECTIVES: To evaluate the efficacy of mass spirometry use for the detection of airflow obstruction in a high-risk population. DESIGN: Free spirometry was offered to smokers who were > 39 years of age with a smoking history of > 10 pack-years. Action was preceded by the dissemination of information on the causes and symptoms of COPD in the local mass media. SETTING: Pulmonary outpatient clinics in 12 large cities of Poland. PARTICIPANTS: Eleven thousand twenty-seven subjects with the following characteristics were screened: mean (+/- SD) age, 51.8 +/- 12.5 years; men, 57%; current or ex-smokers, 80%; and mean smoking history, 26.1 +/- 16.8 pack-years. INTERVENTIONS: Smoking history, simple spirometry (FVC and FEV(1)), and an antismoking advice. RESULTS: Spirometric signs of airway obstruction were found in 24.3% of the subjects who were screened. Of those subjects, mild obstruction was found in 9.5%, moderate obstruction was found in 9.6%, and severe obstruction was found in 5.2%. In smokers aged > or = 40 years who had a smoking history of > 10 pack-years, airway obstruction was found in 30.6%. Airway obstruction was present in 8.3% of smokers < 40 years of age who had a smoking history of < 10 pack-years. Of the 2,200 subjects who had never smoked in their lives, airway obstruction was found in 14.4%. CONCLUSIONS: Mass spirometry in high-risk groups is an effective and easy method for the early detection of COPD.     

Patterns of lung disease in a "normal" smoking population: are emphysema and airflow obstruction found together?

STUDY OBJECTIVES: We determined whether emphysema demonstrated on high-resolution CT (HRCT) scanning in apparently well smokers is associated with airflow obstruction. INTERVENTIONS: Lung function testing and limited HRCT scanning. DESIGN: Lung function measurements and scans were analyzed independently of each other. We used analysis of covariance to compare FEV(1) and maximum expiratory flow at 50% of vital capacity (MEF(50)) values after suitable corrections, between subjects with and without parenchymal damage (emphysema and/or reduced carbon monoxide transfer coefficient [KCO]), and to compare indexes of parenchymal damage between subjects with and without airflow obstruction. SETTING: Radiology and lung function departments of a district general hospital. PARTICIPANTS: Eighty current cigarette smokers and 20 lifetime nonsmoking control subjects (aged 35 to 65 years) who volunteered following publicity in local media. In all subjects, FEV(1) was > 1.5 L; no subjects were known to have lung disease. Measurements and results: FEV(1) and MEF(50) were measured spirometrically; static lung volumes were measured by helium dilution and body plethysmography; KCO was measured by a single-breath technique. HRCT scans were analyzed for emphysema by two radiologists. Of smokers, 25% had HRCT emphysema, generally mild; 16.3% and 25% had reduced FEV(1) and MEF(50), respectively; 12.5% had reduced KCO. Smokers with airflow obstruction were not more likely to have parenchymal damage. Smokers with parenchymal damage did not have reduced airway function. Nonsmokers generally had normal airways and parenchyma. CONCLUSIONS: "Normal" smokers with lung damage had either airflow obstruction or parenchymal damage, but not generally both.     

The FEV1/FEV6 predicts lung function decline in adult smokers

The use of FEV1/FEV6 in place of the traditional FEV1/FVC to detect airways obstruction during spirometry testing performed by primary care providers would reduce time and patient effort. We hypothesized that the FEV1/FEV6, would predict the subsequent decline in FEV1 in adult cigarette smokers who enrolled in the multicenter Lung Health Study. Ten clinical centers in the U.S. and Canada recruited 5887 male and female smokers, aged 35-60 years, with borderline to mild airways obstruction by spirometry. Those who successfully stopped smoking during the 5-yr study (usually as the result of the smoking cessation intervention) were excluded from this analysis. In those continuing to smoke, the relative strength of spirometric predictors of the change in FEV1 during 5 years of follow-up (DFEV1) was determined using a linear regression model. The following covariates were significant independent predictors of DFEV1: the baseline degree of airways obstruction, age, gender, cigarettes per day, years of education, and bronchial hyperresponsiveness. The FEV1/FEV6 was nearly as strong an independent predictor as was the FEV1/FVC (a traditional index of airways obstruction). The degree of airways obstruction, as determined by the FEV1/FEV6 from spirometry, is an independent predictor of subsequent decline in lung function; and therefore, may be used to detect smokers at higher risk of developing COPD.     

Difference in airflow obstruction between Hispanic and non-Hispanic White female smokers

Smoking-related respiratory diseases are a major cause of morbidity and mortality. However, the relationship between smoking and respiratory disease has not been well-studied among ethnic minorities in general and among women in particular. The objective of this cross-sectional study was to evaluate the risk of airflow obstruction and to assess lung function among Hispanic and non-Hispanic White (NHW) female smokers in a New Mexico cohort. Participants completed a questionnaire detailing smoking history and underwent spirometry testing. Outcomes studied included airflow obstruction, selected lung function parameters, and chronic mucus hyper-secretion. Chi square, logistic, and linear regression techniques were utilized. Of the 1,433 eligible women participants, 248 (17.3%) were Hispanic; and 319 had airflow obstruction (22.3%). Hispanic smokers were more likely to be current smokers, and report lower pack-years of smoking, compared to NHW smokers (p < 0.05 for all analyses). Further, Hispanic smokers were at a reduced risk of airflow obstruction compared to NHW smokers, with an O.R. of 0.51, 95% C.I. 0.34, 0.78 (p = 0.002) after adjustment for age, BMI, pack-years and duration of smoking, and current smoking status. Following adjustment for covariates, Hispanic smokers also had a higher mean absolute and percent predicted post-bronchodilator FEV(1)/FVC ratio, as well as higher mean percent predicted FEV(1) (p < 0.05 for all analyses). Hispanic female smokers in this New Mexico-based cohort had lower risk of airflow obstruction and better lung function than NHW female smokers. Further, smoking history did not completely explain these associations.     

The prevalence of airflow obstruction in rural primary care

Spirometry has been reported to be under-utilized, and airflow obstruction may be under-diagnosed, in primary care practice. STUDY OBJECTIVES: The objective of this study was to determine the prevalence and severity of airflow obstruction in rural primary care settings and the degree to which it can be predicted by clinical characteristics. Spirometry was performed in patients 35 years and older who had smoked, presenting for any reason to one of eight rural primary care practices. Obstruction was defined as an FEV(1)/FVC<0.70. A total of 1046 subjects were recruited of whom 1034 had acceptable and reproducible spirometry. Airflow obstruction was detected in 17.4% (180 patients). Of those with obstruction, 77.2% (se 3.1%) had at least one respiratory symptom versus 62.4% (se 1.6%) without obstruction (P=0.0002). Only 44.9% (se 3.7%) of those with airflow obstruction had been previously diagnosed with obstructive lung disease. Of those with an FEV(1)<50% of predicted, 85% (se 5.6%) were breathless on exertion; however, only 63% (se 7.6%) were being treated with respiratory medications. We conclude that airflow obstruction is common in rural primary care practice and cannot be accurately predicted by symptoms. It is undiagnosed half of the time, and often not treated even when symptomatic.     

Small airway function improvement after smoking cessation in smokers without airway obstruction

OBJECTIVE: Studying smokers with normal spirometry requires monitoring tools of the peripheral lung. A validated multiple breath washout technique was used to assess possible recovery of smoking-induced small airway malfunction in acinar and conductive lung zones. METHODS: Eighty-seven smokers with a smoking history of at least 10 pack-years but absence of spirometric airflow obstruction were invited for assessment of lung function and small airway function at baseline and after 1 wk, 3 mo, 6 mo, and 12 mo of smoking cessation. A control group of 16 persistent smokers was studied at the same time intervals. MEASUREMENTS AND MAIN RESULTS: Of the 87 smokers, 66, 32, 28, and 21% successfully ceased smoking for 1 wk, 3 mo, 6 mo, and 12 mo, respectively. Lung function parameters remained essentially unaffected by smoking cessation. Ventilation heterogeneity showed transient improvements after 1 wk in the acinar lung compartment with a return to baseline afterwards. By contrast, there were persistent improvements in the conductive airway compartment; for example, smokers who successfully quit smoking for 12 mo (n=18) showed a 30 and 42% reduction of conductive airways abnormality after 1 wk and 1 yr, respectively. CONCLUSIONS: Smokers with early signs of small airway malfunction who successfully quit smoking show sustained improvements of conductive airway malfunction. In contrast, acinar airway malfunction quickly returns to baseline after a transient improvement.     

Airways obstruction in rheumatoid arthritis.

Owing to the report of an association between rheumatoid arthritis (RA) and obliterative bronchiolitis we have determined the prevalence of airflow obstruction in unselected patients with RA and normal chest radiographs. Spirometry was performed on 100 patients with rheumatoid arthritis and 84 control subjects matched for age, sex, and smoking habits. Patients with rheumatoid arthritis had significantly lower values for FEV1, FVC, FEV1/FVC, and MMEFR when compared with the controls: 39 patients had abnormal spirometry, and at least 32 showed airways obstruction. The prevalence of airflow obstruction is remarkably high, and we suggest that airway disease may be the commonest form of lung involvement in rheumatoid arthritis.     

Effects of smoking cessation on lung function and airway inflammation in smokers with asthma

RATIONALE: Active smoking in asthma is associated with worsening of symptoms, accelerated decline in lung function, and impaired response to corticosteroids. OBJECTIVES: To examine the short-term effects of smoking cessation on lung function, airway inflammation, and corticosteroid responsiveness in smokers with asthma. METHODS AND MEASUREMENTS: Smokers with asthma were given the option to quit or continue smoking. Both groups underwent spirometry and induced sputum at baseline and at 1, 3, and 6 wk. Cutaneous vasoconstrictor response to topical beclometasone, airway response to oral prednisolone, and sensitivity of peripheral blood lymphocytes to corticosteroids were measured before smoking cessation and at 6 wk. MAIN RESULTS: Of 32 subjects recruited, 11 opted to continue smoking (smoking control group). Of 21 subjects who opted for smoking cessation, 10 quit smoking for 6 wk (quit group). In the comparison of quitters with smokers at 6 wk, the mean (confidence interval [CI]) difference in FEV(1) was 407 ml (21, 793), p = 0.040, and the proportion of sputum neutrophils was reduced by 29 (51, 8), p = 0.039. Total cutaneous vasoconstrictor response score to topical beclometasone improved after smoking cessation with a mean (CI) difference of 3.56 (0.84, 6.28), p = 0.042, between quitters and smokers. There was no change in airway corticosteroid responses after smoking cessation. CONCLUSIONS: By 6 wk after smoking cessation, subjects who quit smoking had achieved considerable improvement in lung function and a fall in sputum neutrophil count compared with subjects who continued to smoke. These findings highlight the importance of smoking cessation in asthma.     

Lower respiratory illnesses promote FEV(1) decline in current smokers but not ex-smokers with mild chronic obstructive pulmonary disease: results from the lung health study

We analyzed Lung Health Study (LHS) data to assess the effect of self-reported lower respiratory illnesses resulting in physician visits (LRI) on lung function. Participants were 5,887 smokers aged 35-60 yr, FEV(1)/FVC < 0.70 and FEV(1) of 55-90% predicted. Two-thirds were randomized into an intensive smoking cessation program (SI); one-third were advised only to stop smoking (UC). For 5 yr participants had annual spirometry and questioning regarding LRI. SI had greater rates of smoking cessation than usual care (UC) with fewer LRI (p = 0.0008). Sustained quitters had fewer LRI than continuing smokers (p = 0.0003). In the year LRI occurred, FEV(1) did not change in sustained quitters, but decreased significantly in smokers (p = 0.0001) with some recovery the following year if no LRI occurred. Over 5 yr, LRI had a significant effect on rate of decline of FEV(1) only in smokers. In smokers averaging one LRI/yr over 5 yr there were additional declines in FEV(1) of 7 ml /yr (p = 0.001). Smokers with more than one LRI/yr had greater declines. Chronic bronchitis was associated with increased frequencies of LRI, but did not affect their influence on lung function. Smoking and LRI had an interactive effect on FEV(1) in people with mild COPD, and in smokers frequent LRI may influence the long-term course of the disease.     

The use of microspirometry in detecting lowered FEV1 values in current or former cigarette smokers

AIMS: COPD is an underdiagnosed disease. This study was undertaken to assess the value of microspirometry in detecting reduced FEV1 values in cigarette smokers, i.e., subjects at high risk for COPD. METHODS: A total of 611 smokers or ex-smokers with a smoking history >20 years and no previously-diagnosed lung disease were recruited (389 male, age 27-83 years, mean age 56 years, mean smoking history 35 pack years, 19% ex-smokers). RESULTS: An FEV1 < 80% predicted on microspirometry was found in 44.6% of cases. The mean FEV1 was 2.8 litres (80.6% predicted, range 26-121%). This correlated well with values obtained from full spirometry (R=0.965, p<0.0001). Detailed questionnaire responses revealed that almost half of the subjects (48.2%) reported chronic cough and sputum production and 39.8% reported breathlessness during exercise. CONCLUSIONS: Microspirometry finds a considerable number of smokers or ex-smokers with reduced FEV1 values. Microspirometry is quick to perform. All smokers with reduced microspirometry FEV1 values would benefit from smoking cessation, and all patients with reduced FEV1 values need to be considered for full spirometry to confirm if they actually have COPD.     

A prospective evaluation of plain radiographic signs of chronic obstructive pulmonary disease.

Plain film signs of COPD, spirometric evidence of airflow obstruction, and smoking history were correlated in a group of 182 men aged 32 to 85 years (average, 57.5 years) who presented for evaluation of possible pulmonary disability. There were 148 current or past smokers (range, 0.66 to 150 pack-years; average, 31.89 pack-years) and 34 lifetime nonsmokers. A single observer, who had no knowledge of the other parameters, prospectively evaluated posteroanterior chest radiographs for 11 signs of COPD. Airflow obstruction was defined as a reduction in FEV1/FVC% below the 95% confidence limit of normal. Obstruction was classified on the basis of the reduction in FEV1 as mild (FEV1 greater than 2.5L), moderate (FEV1 greater than 1.0 L and less than 2.5 L), or severe (FEV1 less than 1.0 L). Spirometric evidence of airflow obstruction was present in 67 patients; obstruction was mild in 26, moderate in 36, and severe in 5. We found a statistically significant association between smoking and airflow obstruction on spirometry (P less than 0.001) and an equally significant association between smoking and radiographic signs of COPD on plain chest films (P less than 0.001). Both airflow obstruction and radiologic signs of COPD were generally absent in lifetime nonsmokers. The plain film signs of COPD were only of moderate value in predicting spirometric evidence of airflow obstruction in smokers; spirometric evidence is not the gold standard for the presence of COPD, however, and the strong association between smoking and these radiologic signs may indicate that in smokers the presence of plain film signs of COPD reflects morphologic abnormality in the lungs indicative of disease.(ABSTRACT TRUNCATED AT 250 WORDS)     

The health impact of undiagnosed airflow obstruction in a national sample of United States adults

To determine the health and functional impact of undiagnosed airflow obstruction for subjects in the general population, we used data obtained as part of the Third National Health and Nutrition Examination Survey (NHANES III). Categories of diagnosed and undiagnosed airflow obstruction were defined using questionnaire responses and spirometric results. Health and functional impact of airflow obstruction was assessed from responses to questions about general health status, walking 1/4 mile, lifting or carrying something as heavy as 10 lb, or needing help with personal care. Undiagnosed airflow obstruction (12.0%) was more common than doctor-diagnosed chronic obstructive pulmonary disease (COPD) (3.1%) or asthma (2.7%). Although undiagnosed airflow obstruction was usually very mild, approximately 5% of the entire sample had an FEV(1) less than 75% predicted. After adjusting for smoking, obesity, and comorbid conditions, the risk of impaired health and functional status with undiagnosed airflow obstruction was independently associated with severity of FEV(1) impairment. For males and females, ever smoking was strongly associated with all types of airflow obstruction, diagnosed or not. However, among females with airflow obstruction, 12.2% to 35.2% never smoked. Undiagnosed airflow obstruction is common in the general population of the United States and is associated with impaired health and functional status. Keywords: airflow obstruction; spirometry; health impact; screening     

Predictors of survival in severe, early onset COPD

STUDY OBJECTIVES: Multiple risk factors for mortality in patients with COPD have been described, but most studies have involved older, primarily male subjects. The purpose of this study was to determine the mortality rate and predictors of survival in subjects with severe, early onset COPD. DESIGN, SETTING, AND PARTICIPANTS: The cohort of 139 probands in the Boston Early-Onset COPD Study was recruited from lung transplant and general pulmonary clinics between September 1994 and July 2002. Subjects were < 53 years old, had an FEV(1) of < 40% of predicted, did not have severe alpha(1)-antitrypsin deficiency, and had not undergone lung transplantation. The initial evaluation included a standardized respiratory questionnaire, spirometry, and a blood sample. A follow-up telephone interview was conducted between May and December 2002. MEASUREMENTS AND RESULTS: Subjects were young (mean age at enrollment, 47.9 years) and had severe airflow obstruction (mean baseline FEV(1), 19.4% predicted). A total of 72.7% of the subjects were women (p < 0.0001 [comparison to equal gender distribution]). The median estimated survival time was 7.0 years from the time of study enrollment, determined by the Kaplan-Meier method. The majority of deaths were due to cardiorespiratory illness. In a multivariable Cox proportional hazards model, adjusting for age, gender, and baseline FEV(1), lifetime cigarette consumption (hazard ratio [HR], 1.20 [per 10 pack-years]; 95% confidence interval [CI], 1.02 to 1.40) and recent smoking status (HR, 2.50; 95% CI, 1.03 to 6.05) were both significant predictors of mortality. CONCLUSION: In this cohort, recent smoking status predicted increased mortality independent of the effects of lifetime smoking intensity. Smoking cessation may confer a survival benefit even among patients with very severe COPD.     

Diagnosis of airflow limitation combined with smoking cessation advice increases stop-smoking rate

OBJECTIVES: To assess how the diagnosis of airflow limitation (AL) combined with advice to stop smoking in middle-aged smokers influence the smoking cessation rate and to identify predictors of successful outcome. DESIGN: Prospective, single-center, comparative study of the effects of smoking intervention in smokers with diagnosed AL and in smokers with normal lung function (NLF). SETTING: University hospital, out-patient clinic. PARTICIPANTS: Of 659 smokers participating in a population spirometric screening for COPD combined with smoking cessation advice, 558 (AL, 297 smokers; NLF, 261 smokers) were invited for a follow-up after 1 year. INTERVENTION: At follow-up, spirometry was repeated and smoking status was assessed. Nonsmoking status was validated with carbon monoxide measurements in exhaled air. Patients who did not come for the follow-up visit were considered to be smokers. RESULTS: Of 558 smokers invited, 368 (66%) presented for the follow-up visit. All had tried to reduce their smoking habit. The number of cigarettes smoked per day (cpd) at 1 year was - 5.2 (p < 0.01) in patients with AL and - 2.7 (not significant [NS]) in those with NLF. The 1-year cessation rate in smokers with AL was 10.1% vs 8.4% in smokers with NLF (NS). After stratifying the patients according to AL severity, the highest cessation rate was observed in smokers with moderate and severe AL (16.5%) compared to smokers with mild AL (6.4%; p < 0.001) and smokers with NLF (8.4%; p < 0.05). In a univariate analysis, the cessation of smoking was correlated with older age (p < 0.001), later age when starting smoking (p < 0.005), lower tobacco exposure (in pack-years; p < 0.01), fewer cpd (p < 0.001), and lower lung function (p < 0.05). No interaction effect was observed for any of the studied variables using two-way analysis of variance. In a stepwise logistic regression analysis, age (p < 0.001), tobacco exposure (in pack-years; p < 0.001), and FEV(1) percent predicted (p < 0.01) proved to be significant predictors of success in stopping smoking. CONCLUSION: All smokers, irrespective of their lung function, tried to modify their habit as the result of screening for COPD combined with smoking cessation advice. The diagnosis of AL motivated smokers to attempt to quit smoking. Older age, lower tobacco exposure, and lower lung function were the predictors of success in quitting smoking.     

Impact of cigarette smoking on decline in forced expiratory volume in 1 s relative to severity of airflow obstruction in a Japanese general population: The Yamagata–Takahata study

Background

Few studies are available regarding the annual decline of forced expiratory volume in 1 s (FEV1) in chronic obstructive pulmonary disease patients with mild airflow obstruction. This study sought to clarify to what extent cigarette-smoking individuals with mild airflow obstruction lose pulmonary function annually.

Diagnosis and management of stable chronic obstructive pulmonary disease: a clinical practice guideline from the American College of Physicians

RECOMMENDATION 1: In patients with respiratory symptoms, particularly dyspnea, spirometry should be performed to diagnose airflow obstruction. Spirometry should not be used to screen for airflow obstruction in asymptomatic individuals. (Grade: strong recommendation, moderate-quality evidence.) RECOMMENDATION 2: Treatment for stable chronic obstructive pulmonary disease (COPD) should be reserved for patients who have respiratory symptoms and FEV1 less than 60% predicted, as documented by spirometry. (Grade: strong recommendation, moderate-quality evidence.) RECOMMENDATION 3: Clinicians should prescribe 1 of the following maintenance monotherapies for symptomatic patients with COPD and FEV1 less than 60% predicted: long-acting inhaled beta-agonists, long-acting inhaled anticholinergics, or inhaled corticosteroids. (Grade: strong recommendation, high-quality evidence.) RECOMMENDATION 4: Clinicians may consider combination inhaled therapies for symptomatic patients with COPD and FEV1 less than 60% predicted. (Grade: weak recommendation, moderate-quality evidence.) RECOMMENDATION 5: Clinicians should prescribe oxygen therapy in patients with COPD and resting hypoxemia (Pao2 < or =55 mm Hg). (Grade: strong recommendation, moderate-quality evidence.) RECOMMENDATION 6: Clinicians should consider prescribing pulmonary rehabilitation in symptomatic individuals with COPD who have an FEV1 less than 50% predicted. (Grade: weak recommendation, moderate-quality evidence.).     

Predicting inadequate spirometry technique and the use of FEV1/FEV3 as an alternative to FEV1/FVC for patients with mild cognitive impairment

Introduction and Objectives: Some patients cannot perform forced vital capacity (FVC). We conducted a study to answer three questions: Can the ability to perform components of spirometry be predicted by the Mini Mental State Examination (MMSE)? What proportion of subjects can perform forced expiratory volume in 3 s (FEV3) but not FVC? Does the forced expiratory volume in 1 s (FEV1)/FEV3 ratio concord with FEV1/FVC ratio in patients with airflow obstruction? Methods: We conducted a prospective observational study of 267 patients with a mean age of 79 years, including subjects with indicators of frailty. They performed spirometry and the MMSE. Spirometric recordings were compared to the American Thoracic Society 1994 criteria. Results: FVC was achieved by 51% of patients. Inability to perform FVC was predicted by an MMSE < 24 (specificity 94%, sensitivity of 51%). An FEV1/FEV3 ratio < 80% matched a FEV1/FVC ratio < 70% (sensitivity 96%, specificity 97%). Twenty‐five percent of subjects were able to reach FEV3 but not FVC; 14% of that group had an MMSE < 24. Subjects with an MMSE < 20 were unable reliably to perform any spirometry. Conclusion: Patients with an MMSE < 24 are usually unable to reach FVC reliably when tested on a single occasion, but some can reach FEV3. Patients with MMSE < 20 cannot do spirometry. An FEV1/FEV3 ratio < 80% can be used to help identify patients with airflow obstruction if they are unable to perform full spirometry to FVC. Please cite this paper as: Allen S, Yeung P, Janczewski M and Siddique N. Predicting inadequate spirometry technique and the use of FEV1/FEV3 as an alternative to FEV1/FVC for patients with mild cognitive impairment. The Clinical Respiratory Journal 2008; 2: 208–213.     

The measurement of exhaled carbon monoxide is influenced by airflow obstruction.

The concentration of carboxyhaemoglobin (COHb) is often estimated from measurements of carbon monoxide in the exhaled air (COexh). This study investigates whether the presence of airflow obstruction significantly alters the relationship between COexh and COHb. Eighty-one regular smokers were prospectively studied and divided in four groups according to the presence and severity of airflow obstruction (none, mild, moderate, severe). In each subject, the authors measured in this order: 1) arterial blood gases; 2) haemoglobin concentration and COHb (by co-oxymetry); 3) COexh; 4) lung volumes; and 5) forced spirometry. The size of the measurement error (deltaCO) was calculated from the difference between COHb and COexh. Neither the smoking history nor COexh were different in the four groups of subjects studied. In contrast, deltaCO increased in parallel to the degree of airflow obstruction. DeltaCO was >2% (a threshold value normally used in the clinic to separate smokers from nonsmokers) only in patients with severe airflow obstruction. A stepwise multivariate analysis showed that both forced expiratory volume in one second (FEV1) (percentage reference) and COHb contributed significantly (p<0.0001) to predict deltaCO. This study shows that the estimation of carboxyhaemoglobin from exhaled carbon monoxide measurements can be inaccurate in patients with severe airflow obstruction. In these patients, the direct measurement of carboxyhaemoglobin seems advisable in clinical practice.     

Bronchial airflow limitation, smoking, body mass index, and statin use are strongly associated with the C-reactive protein level in the elderly. The Tromsø Study 2001

BACKGROUND: Bronchial airflow limitation is a known predictor of raised C-reactive protein (CRP) level. The aim of this study was to explore this association in an elderly population, as well as the influence of other known and possible predictors of the CRP level, like smoking and the use of statins and inhaled corticosteroids. POPULATION AND METHODS: The study population consists of 3877 Norwegians aged 60 years or more who took part in the fifth Troms? study in 2001, a cross-sectional study. The examinations included questionnaires, spirometry and the measurement of CRP. RESULTS: A geometric mean CRP value of 3.15 mg/L was found in subjects with severe airflow limitation (FEV(1)%<50 predicted and FEV(1)/FVC<70%), compared to 1.64 mg/L in subjects with normal spirometry, (p<0.001), and 19% of the subjects with severe airflow limitation had a CRP value above 10 mg/L compared to 4.9% in those with mild airflow limitation or normal spirometry. Elevated body mass index (BMI), smoking, hormone replacement therapy, and increasing age, were also strong independent predictors of increased CRP. Statin use was a strong predictor of decreased CRP level, while the use of inhaled corticosteroids was not associated with decreased CRP values. CONCLUSION: We found a strong link between bronchial airflow limitation and the circulating CRP level in an elderly population, independent of self-reported diseases, medication, smoking, and elevated BMI. The CRP value increased with increasing age in men, but not in women, which may be partly explained by a greater impact of chronic obstructive pulmonary disease (COPD) morbidity on the CRP level in men than in women. Measuring CRP may show to be a useful part of the diagnostic work-up in COPD patients.