The proportional Venn diagram of obstructive lung disease: two approximations from the United States and the United Kingdom

STUDY OBJECTIVES: The nonproportional Venn diagram of obstructive lung disease (OLD) produced for the 1995 American Thoracic Society guidelines has not been quantified. We aim to quantify the proportion of the general population with OLD and the intersections of physician-diagnosed asthma, chronic bronchitis, and emphysema in the United States and the United Kingdom, and to examine the relationship to obstructive spirometry. DESIGN AND PARTICIPANTS: We analyzed data from the US National Health and Nutrition Examination (NHANES) III survey (1988 to 1994) and the UK General Practice Research Database for the year 1998. RESULTS: The areas of intersection among the three OLD conditions produced seven mutually exclusive disease groups. The asthma-only group was the largest proportion of OLD patients, accounting for 50.3% and 79.4% of all OLD patients in the United States and the United Kingdom, respectively, and decreased with increasing age. Overall, 17% and 19% of OLD patients in the United States and in the United Kingdom, respectively, reported more than one OLD condition, and this percentage increased with age. According to the spirometry data from NHANES III, only 37.4% of emphysema-only patients had objective airflow obstruction. The prevalence of airflow obstruction was significantly higher among participants with combinations of emphysema and chronic bronchitis (57.7%), with emphysema and asthma (51.9%), and with all three OLD diseases concomitantly (52.0%). CONCLUSION: Concomitant diagnosis of asthma, chronic bronchitis, or emphysema is common among OLD patients from the general population, particularly in adults aged > or = 50 years.     

Airway obstruction is common but unsuspected in patients admitted to a general medicine service

STUDY OBJECTIVES: Obstructive lung disease (OLD) is a worldwide health problem with major impact on health and economics, and can be easily diagnosed by spirometry. Recent expert panels have emphasized the underreporting and underrecognition of this condition. The goal of this study was to measure the prevalence of airway obstruction in patients admitted to an urban teaching hospital and to determine the frequency of a diagnosis of OLD at admission or discharge. METHODS: Prospective study of 153 patients admitted to a medicine service at the Johns Hopkins Hospital in Baltimore, MD. Patients completed bedside spirometry and a questionnaire. RESULTS: Twenty-six percent of patients had airway obstruction (FEV(1)/FVC < 70%), including 6% with a very severe airway obstruction (FEV(1) < 30% predicted). At hospital discharge, a clinical diagnosis of OLD was present in only 33% of patients with mild airway obstruction (FEV(1) > 70% predicted), 30% of patients with moderate airway obstruction (FEV(1) 50 to 69% predicted), 33% of patients with severe airway obstruction (FEV(1) 30 to 49% predicted), and 89% of patients with very severe airway obstruction (FEV(1) < 30% predicted). Only 40% of patients with airway obstruction were receiving bronchodilator medication at hospital admission or discharge. CONCLUSIONS: Airway obstruction is common in hospitalized patients and is usually undiagnosed and untreated. Spirometry may be a useful component of the examination of hospitalized medical patients to identify OLD.     

The validity of the diagnosis of chronic obstructive pulmonary disease in general practice.

AIM: To determine the validity of the diagnosis of chronic obstructive pulmonary disease (COPD) in general practice in patients given a diagnosis of COPD and treated with bronchodilators. METHODS: From the medical records of eight Health Centres in Northern Greece, 319 subjects aged over 40 years and diagnosed as "COPD" were entered into the study. All filled in a special questionnaire and were subjected to spirometry, rhinomanometry and chest X-ray. RESULTS: One hundred and sixty patients (50.2%) met the GOLD criteria for COPD. Twenty-six of them were non-smokers and underwent further evaluation: blood eosinophil count, serum IgE assay, high resolution computed tomography (HRCT) scan of the chest, and echocardiography; 16 were given a different diagnosis. One hundred and fifty-nine subjects (49.8%) with an FEV1/ FVC ratio >0.7 did not meet the GOLD criteria for COPD; 71 suffered from nasal obstruction, 13 from asthma, six had restrictive pulmonary disease and 69 had no respiratory disease. CONCLUSION: Diagnostic errors in patients with respiratory symptoms in the primary healthcare setting are frequent. Patients suspected to have COPD should undergo spirometry testing after bronchodilation. An alternative diagnosis must be sought for non-smoking patients with irreversible airway obstruction.     

Attaining a correct diagnosis of COPD in general practice

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is common. Diagnosis should include objective evidence of airways obstruction and spirometry is recommended in guidelines and the general medical services contract in the UK. We assessed the impact of spirometry in general practice. METHOD: We determined by questionnaire the availability, staff training, use and the interpretation results of spirometry in 72% of general practices in Wales. We reviewed the diagnosis of COPD previously made in two general practices without spirometry. RESULTS: Most practices had a spirometer (82.4%) and used it (85.6%). Confidence in use and interpretation of results varied widely: 58.1% were confident in use and 33.8% confident in interpretation. Spirometry was performed more often if confident in use and interpretation (both P<0.001) and was related to greater training periods (P<0.001). Spirometric confirmation of COPD varied widely (0-100%, median 37%). Of the 125 patients previously diagnosed with COPD 61 had spirometric confirmation, while 25 had reversible obstruction (range 210-800 mls), 34 had normal and 5 had restrictive spirometry. CONCLUSION: Despite incentives to perform spirometry in general practice, lack of adequate training in use and interpretation suggests use is confounded and the diagnosis of COPD is likely to be made on imprecise clinical grounds.     

Symptom-based questionnaire for differentiating COPD and asthma

BACKGROUND: Many patients with obstructive lung disease (OLD) carry an inaccurate diagnostic label. Symptom-based questionnaires could identify persons likely to need spirometry. OBJECTIVES: We prospectively tested questions derived from a comprehensive literature review and an international Delphi panel to help identify chronic OLD (COPD) in persons with prior evidence of OLD. METHODS: Subjects were recruited via random mailing to primary-care practices in Aberdeen, Scotland, and Denver, Colorado. Persons aged 40 and older reporting any prior diagnosis of OLD or any respiratory medications in the past year were enrolled. Participants answered 54 questions covering demographics and symptoms and underwent spirometry with reversibility testing. A study diagnosis of COPD was defined by fixed airway obstruction as measured by post-bronchodilator FEV(1)/FVC <0.70. We examined ability of individual questions in a multivariate framework to discriminate between persons with and without the study diagnosis of COPD. RESULTS: 597 persons completed all investigations and proceeded to analysis. The list of 54 questions yielded 52 items for analyses, which was reduced to 19 items for entry into a multivariate regression model. Nine items had significant relationships with the study diagnosis of COPD, including increased age, pack-years, worsening cough, breathing-related disability or hospitalization, worsening dyspnea, phlegm quantity, cold going to the chest, and receipt of treatment for breathing. Individual items yielded odds ratios ranging from 0.33 to 20.7. This questionnaire demonstrated a sensitivity of 72.0 and a specificity of 82.7. CONCLUSIONS: A short, symptom-based questionnaire identifies persons more likely to have COPD among persons with prior evidence of OLD.     

The proportional Venn diagram of obstructive lung disease in the Italian general population

STUDY OBJECTIVES: The Venn diagram of obstructive lung disease (OLD) has been recently quantified. We aimed to quantify the proportion of the general population with OLD, and the intersections of physician-diagnosed asthma, chronic bronchitis (CB), and emphysema in two Italian general population samples, in relationship to airflow obstruction (AO) determined through spirometry. DESIGN AND PARTICIPANTS: We analyzed data from two prospective studies (4,353 patients) carried out in the rural area of Po River delta from 1988 to 1991 and in the urban area of Pisa from 1991 to 1993. RESULTS: Prevalence rates of asthma, CB, and emphysema were 5.3%, 1.5%, and 1.2% in the Po delta, and 6.5%, 2.5%, and 3.6% in Pisa. A double Venn diagram, which was used to quantify the distribution of CB, emphysema, and asthma in relation to the presence/absence of AO, identified 15 categories. Isolated AO was the most frequent category (Po delta, 11.0%; Pisa, 6.7%), followed by asthma only without AO (Po delta, 3.3%; Pisa, 4.3%). The combination of the three OLD conditions was the only category that always showed higher prevalence rates for those with AO (Po delta, 0.20%; Pisa, 0.16%) than for those without AO (Po delta, 0.04%; Pisa, 0.05%). Of those with either OLD or AO, there were 61.4% in Po delta and 38.2% in Pisa with isolated AO, 24.8% and 41.9%, respectively, with an OLD without AO, and 13.8% and 19.9%, respectively, with simultaneous OLD and AO. For both genders, the frequency of isolated asthma decreased with age, while that of isolated AO, CB-emphysema, and the combination of asthma and CB-emphysema increased. CONCLUSION: About 18% of the Italian general population samples either reported the presence of OLD or showed spirometric signs of AO. We confirmed that the Venn diagram of OLD can be quantified in the general population by extending the mutually exclusive disease categories (including a concomitant diagnosis of asthma, CB, or emphysema) to 15.     

National survey of spirometer ownership and usage in general practice in Australia

OBJECTIVES AND BACKGROUND: Despite the lack of data, it is believed that spirometry is underutilized in general practice. The aim of the present study was to determine the availability of spirometry and the level of spirometry training in general practice throughout Australia and compare with international data. METHODS: In total, 5976 general practices throughout Australia were sent a questionnaire requesting details of spirometer ownership, usage and the level and source of spirometry training. To exclude response bias, a follow-up telephone survey was conducted of 160 practices that did not respond to the initial survey. RESULTS: Of practices 19.5% (1125) responded to the initial survey with 64.2% (722) of these owning a spirometer and 83.9% in the follow-up sample. Common reasons for not owning a spirometer were equipment cost (53.3%) and insufficient remuneration (32.8%). Most practices (67.0%) performed one or more tests per week. Practices commonly used spirometry to diagnose (89.5%) and manage (93.9%) asthma, assess breathlessness (83.4%) and to detect and manage other diseases such as COPD (77.7%). Spirometer accuracy was never checked using a syringe 77.8% of practices and 40% did not test a healthy subject as part of their quality assurance programme. Spirometry training was received most commonly through courses run by general practice organizations (38.2%), and the duration of training courses was <2 h in 40% of cases. CONCLUSION: Despite high spirometer ownership in general practice, the frequency of use is low. Low rates of verification of spirometer accuracy and performance suggest the need for reliable, stable spirometers to be available to general practitioners. Regular and more comprehensive training in spirometry is needed.     

Diagostic value of respiratory impedance measurements in elderly subjects

Obstructive lung disease (OLD) is highly prevalent in elderly subjects but markedly under-diagnosed. Indeed, only 40-50% of hospitalized elderly patients are able to adequately perform spirometric tests. This study aimed to evaluate, in an acute-care geriatric hospital, the diagnostic value of measuring airway impedance (Zrs) by the forced oscillation technique (FOT) for: (1) identifying OLD and (2) identifying responders vs. non-responders to bronchodilators. Sixty-seven patients (aged 82+/-8 years) underwent consecutive measurement of Zrs and forced expiratory volumes before and after bronchodilators. Zrs was measured by FOT at frequencies of 4-30 Hz. Correlations, ROC curves and logistic regression models were established to determine the sensitivity (Se) and specificity (Sp) of Zrs in identifying OLD. Significant correlations were found between spirometric and Zrs measurements. The Zrs parameters yielding the best Se and Sp for detecting OLD were: Fn (resonant frequency; Se: 76%; Sp: 78%) and R0 (resistance extrapolated for a frequency of 0: Se: 76%; Sp: 74%). Using the logistic regression models, 76% of the patients were correctly classified as having OLD or not. Zrs was however not contributive in identifying responders to bronchodilators. Zrs measurements by FOT are contributive to the diagnosis of OLD in elderly hospitalized patients.     

Prevalence of obstructive lung disease in HIV population: a cross sectional study

Background

Observational studies have suggested an association between HIV infection and emphysema.

Aims

The primary aim of this study was to estimate the prevalence of obstructive lung disease in HIV-infected patients seen in an outpatient infectious disease clinic. The secondary aim was to estimate the prevalence of Obstructive Lung Disease (OLD) in smokers and non smokers in this population.

Methods

This was a prospective cross-sectional study. Consecutive patients who were seen for routine HIV care underwent spirometry and answered the St. George’s Respiratory Questionnaire (SGRQ). Further, we collected information from the charts on demographics, co-morbidities, CD4 cell count, and HIV viral load (current, baseline, etc).

Results

This study included 98 HIV-infected patients with mean age of 45 years, (SD: 11) and 84% male. They were seen from November 2008 to May 2009 at Thomas Jefferson University in Philadelphia. According to established criteria, spirometry results were classified as normal in 69% and obstructive in 16.3%. Among those who never smoked, the prevalence of obstructive lung disease on spirometry was 13.6%. The prevalence of obstruction in HIV patients with a history of smoking was 18.5%. Current and ever smokers comprised 21.4% and 55% of the patients respectively. The mean SGRQ total score was 7. The mean SGRQ score in active smokers was 17 and 15 in those subjects with a prior history of smoking. The mean SGRQ score among patients with obstruction in spiromerty was 27.7 in patients with obstruction on spirometry.

Conclusion

This urban population of HIV-infected persons has a relatively high prevalence of obstructive lung disease as assessed by spirometry. Furthermore, the high prevalence of obstructive lung disease in never smokers may suggest a possible association between HIV infection and emphysema. In addition the SGRQ total score was comparatively higher in patients with obstruction on spirometry. Our data suggests that potentially all patients with HIV should be screened a for OLD.     

Obstructive lung disease among the urban homeless

STUDY OBJECTIVES: Homelessness is a growing problem in the United States that may significantly impair physical health. The homeless have a high prevalence of cigarette smoking, poor nutrition, and adverse environmental exposures, which could contribute to obstructive lung disease (OLD). Despite this risk, the prevalence of OLD among the homeless remains unknown. We aimed to systematically assess the prevalence of OLD among the urban homeless. DESIGN, SETTING, AND PARTICIPANTS: We conducted a cross-sectional study of the prevalence of OLD among homeless individuals in San Francisco. By random sampling, we recruited 68 adults living in one homeless shelter to participate in a structured interview survey and spirometry assessment. We used a multifaceted approach to assess OLD, including respiratory symptoms, self-reported physician diagnosis of asthma, chronic bronchitis, emphysema, or COPD, and spirometry (defined as FEV1 < 80% predicted and FEV1/FVC ratio < 0.70). RESULTS: Sixty-eight adults completed the survey, and 67 adults completed the spirometry. Homeless adults were likely to be homeless < 1 year and homeless for the first time. There was a high prevalence of cigarette smoking (75% ever smokers, 68% current smokers). The prevalence of symptoms suggestive of OLD was high, including cough (29%), wheezing (40%), chronic bronchitis symptoms (21%), and dyspnea on exertion (29%). A substantial proportion of homeless subjects indicated a prior diagnosis of asthma (24%), chronic bronchitis (19%), and COPD (4%). Based on spirometry, the prevalence of OLD was 15% (95% confidence interval, 8 to 26%), which was more than double the expected prevalence in the general US population. CONCLUSIONS: As OLD is a leading cause of death in the United States, it is important to identify it early for treatment. Homeless individuals have a higher-than-expected prevalence of OLD. Public health interventions should target the homeless population for prevention and treatment of OLD.     

Lung function measurement in general practice: a comparison of the Escort spirometer with the Micromed turbine spirometer and the mini-Wright peak flow meter

It is important that new types of spirometer for widespread clinical use are pragmatically evaluated in primary care. This study compared measurements taken by a new portable Fleisch pneumotachograph spirometer (known as the Escort) with those of the commonly used mini-Wright peak flow meter and the Micromed Pocket turbine spirometer. A pragmatic study was conducted in two phases during routine surgeries at Aldermoor Health Centre, Southampton. Phase 1 compared the new spirometer with the mini-Wright peak flow meter and Phase 2 compared the new spirometer and the turbine spirometer. One hundred patients aged 5–88 years (56 patients with a history of chronic respiratory complaints and 44 patients without) entered Phase 1, and 100 patients aged 6–82 years (62 patients with a history of chronic respiratory complaints and 38 patients without) entered Phase 2. Each patient contributed only once to each phase, but some entered both phases on separate occasions. Ninety-five percent limits of agreement (mean ± 2 ) were wide for all comparisons. Graphical plots revealed trends towards higher Escort values as mean values rose compared with both mini-Wright and turbine readings for peak expiratory flow rate and forced expiratory volume in one second. Possible over-reading of peak expiratory flow rate with the mini-Wright meter at low mean values was also seen. Readings taken with these different types of meter cannot be interchanged with confidence in clinical practice. The clinical significance of the theoretically more accurate measures of lung function produced with the new meter, and indeed of spirometry itself, needs further investigation.     

Can the single-breath helium dilution method predict lung volumes as measured by whole-body plethysmography?

OBJECTIVE:

To compare TLC and RV values obtained by the single-breath helium dilution (SBHD) method with those obtained by whole-body plethysmography (WBP) in patients with normal lung function, patients with obstructive lung disease (OLD), and patients with restrictive lung disease (RLD), varying in severity, and to devise equations to estimate the SBHD results.

METHODS:

This was a retrospective cross-sectional study involving 169 individuals, of whom 93 and 49 presented with OLD and RLD, respectively, the remaining 27 having normal lung function. All patients underwent spirometry and lung volume measurement by both methods.

RESULTS:

TLC and RV were higher by WBP than by SBHD. The discrepancy between the methods was more pronounced in the OLD group, correlating with the severity of airflow obstruction. In the OLD group, the correlation coefficient of the comparison between the two methods was 0.57 and 0.56 for TLC and RV, respectively (p < 0.001 for both). We used regression equations, adjusted for the groups studied, in order to predict the WBP values of TLC and RV, using the corresponding SBHD values. It was possible to create regression equations to predict differences in TLC and RV between the two methods only for the OLD group. The TLC and RV equations were, respectively, ∆TLC_WBP-SBHD in L = 5.264 − 0.060 × FEV₁/FVC (r² = 0.33; adjusted r² = 0.32) and ∆RV_WBP-SBHD in L = 4.862 − 0.055 × FEV₁/FVC (r² = 0.31; adjusted r² = 0.30).

CONCLUSIONS:

The correction of TLC and RV results obtained by SBHD can improve the accuracy of this method for assessing lung volumes in patients with OLD. However, additional studies are needed in order to validate these equations.     

Value of spirometry in detecting volume restriction in interstitial lung disease patients. Spirometry in interstitial lung diseases

BACKGROUND: Restriction is a typical functional abnormality in interstitial lung disease (ILD) patients, but is not always present, especially in the early stage of the disease. The greater reduction of vital capacity (VC; %pred.) than total lung capacity (TLC; %pred.) is regarded as a typical pattern of lung function disturbances in ILD patients. STUDY OBJECTIVES: To explore the diagnostic value of spirometry in a detection restrictive pattern the relative volume loss assessed by TLC and VC in large series of patients with a diagnosis of ILD referred for lung function tests was evaluated. METHODS: Retrospective, cross-sectional analysis of pulmonary function data was done. The sampleconsisted of 1,173 patients with the diagnosis of different interstitial lung diseases investigated during a period of 5 years. Only patients without airway obstruction (normal FEV1%VC) were included. In all cases spirometry and whole body plethysmography were performed by experienced staff using MasterLab - 'Jaeger' equipment according to ERS standards. Reference values according to ERS guidelines were applied. RESULTS: The mean value of TLC expressed as %pred. was significantly (p < 0.001) lower than VC in all patients (93.7 +/- 18.6 vs. 98.0 +/- 21.4%pred.). The frequency of abnormal (lowered) TLC results was also higher than lowered VC (22.8 vs. 17.8%). Sensitivity of VC reached 69.3% and the positive predictive value was 88.5% in detecting volume restriction as compared to TLC measurement. CONCLUSION: The relative loss of TLC was greater than VC in our large group of patients. Measurement of TLC should be part of functional assessment of ILD patients, irrespective of whether they present or do not present a restrictive pattern in spirometry.     

Scoring system and clinical application of COPD diagnostic questionnaires

OBJECTIVES: In most primary care settings, spirometric screening of all patients at risk is not practical. In prior work, we developed questionnaires to help identify COPD in two risk groups: (1) persons with a positive smoking history but no history of obstructive lung disease (case finding), and (2) patients with prior evidence of obstructive lung disease (differential diagnosis). For these questionnaires, we now present a scoring system for use in primary care. METHODS: Scores for individual questions were based on the regression coefficients from logistic regression models using a spirometry-based diagnosis of obstruction as the reference outcome. Receiver operator characteristic analysis was used to determine performance characteristics for each questionnaire. Several simplified scoring systems were developed and tested. RESULTS: For both scenarios, we created a scoring system with two cut points intended to place subjects within one of three zones: persons with a high likelihood of having obstruction (high predictive value of a positive test result); persons with a low likelihood of obstruction (high predictive value of a negative test result); and an intermediate zone. Using these scoring systems, we achieved sensitivities of 54 to 82%, specificities of 58 to 88%, positive predictive values of 30 to 78%, and negative predictive values of 71 to 93%. CONCLUSIONS: These questionnaires can be used to help identify persons likely to have COPD among specific risk groups. The use of a simplified scoring system makes these tools beneficial in the primary care setting. Used in conjunction with spirometry, these tools can help improve the efficiency and accuracy of COPD diagnosis in primary care.     

Can airway obstruction be estimated by lung auscultation in an emergency room setting?

OBJECTIVE: Lung auscultation is a central part of the physical examination at hospital admission. In this study, the physicians' estimation of airway obstruction by auscultation was determined and compared with the degree of airway obstruction as measured by FEV(1)/FVC values. METHODS: Two hundred and thirty-three patients consecutively admitted to the medical emergency room with chest problems were included. After taking their history, patients were auscultated by an Internal Medicine registrar. The degree of airway obstruction had to be estimated (0=no, 1=mild, 2=moderate and 3=severe obstructed) and then spirometry was performed. Airway obstruction was defined as a ratio of FEV(1)/FVC <70%. The degree of airway obstruction was defined on FEV(1)/FVC as mild (FEV(1)/FVC <70% and >50%), moderate (FEV(1)/FVC <50% >30%) and severe (FEV(1)/FVC <30%). RESULTS: One hundred and thirty-five patients (57.9%) had no sign of airway obstruction (FEV(1)/FVC >70%). Spirometry showed a mild obstruction in 51 patients (21.9%), a moderate obstruction in 27 patients (11.6%) and a severe obstruction in 20 patients (8.6%). There was a weak but significant correlation between FEV(1)/FVC and the auscultation-based estimation of airway obstruction in Internal Medicine Registrars (Spearman's rho=0.328; P<0.001). The sensitivity to detect airway obstruction by lung auscultation was 72.6% and the specificity only 46.3%. Thus, the negative predictive value was 68% and the positive predictive value 51%. In 27 patients (9.7%), airway obstruction was missed by lung auscultation. In these 27 cases, the severity of airway obstruction was mild in 20 patients, moderate in 5 patients and severe in 2 patients. In 82 patients (29.4%) with no sign of airway obstruction (FEV(1)/FVC >70%), airway obstruction was wrongly estimated as mild in 42 patients, as moderate in 34 patients and as severe in 6 patients, respectively. By performing multiple logistic regression, normal lung auscultation was a significant and independent predictor for not having an airway obstruction (OR 2.48 (1.43-4.28); P=0.001). CONCLUSION: Under emergency room conditions, physicians can quite accurately exclude airway obstruction by auscultation. Normal lung auscultation is an independent predictor for not having an airway obstruction. However, airway obstruction is often overestimated by auscultation; thus, spirometry should be performed.     

A randomized controlled trial on office spirometry in asthma and COPD in standard general practice: data from spirometry in Asthma and COPD: a comparative evaluation Italian study

STUDY OBJECTIVES: To evaluate whether office spirometry by general practitioners (GPs) is feasible and may improve the diagnosis of asthma and COPD. METHODS: A prospective, randomized, comparative trial was planned involving 57 Italian pulmonology centers and 570 GPs who had to enroll consecutive subjects aged 18 to 65 years with symptoms of asthma or COPD without a previous diagnosis. Patients were randomized 1:1 into two groups with an interactive voice responding system: conventional evaluation alone vs conventional evaluation and spirometry. Office spirometry was performed by GPs who were trained by reference specialists using a portable electronic spirometer (Spirobank Office; MIR; Rome, Italy). Diagnosis was confirmed by the reference specialist center in blind fashion. RESULTS: Seventy-four GPs complied to the trial. Of 333 patients enrolled, 136 nonrandom violators completed the protocol. Per-protocol analysis showed a concordant diagnosis between GPs and specialists in 78.6% of cases in the conventional evaluation-plus-spirometry group vs 69.2% in the conventional evaluation group (p = 0.35). In the intention-to-treat analysis, the respective percentages of concordant diagnosis were 57.9 and 56.7 (p = 0.87). CONCLUSIONS: Office spirometry by GPs is feasible, but frequent protocol violation and inadequate sample size did not allow us to prove a significant advantage of office spirometry in improving the diagnosis of asthma and COPD in standard general practice as organized at present in Italy, thus reinforcing the need for close cooperation between GPs and specialists in respiratory medicine.     

Attitudes of physicians toward objective measures of airway function in asthma

BACKGROUND: The National Asthma Education and Prevention Program (NAEPP) recommends pulmonary function testing as part of asthma evaluation. The objectives of this study were to determine the use of spirometry in patients with asthma by primary care physicians and asthma specialists, and to identify barriers to use of spirometry. METHODS: We developed, validated, and administered a mailed survey to primary care physicians and asthma specialists in the general community. We asked about the use of spirometry, access to spirometry, and barriers to spirometry use. RESULTS: Of 975 eligible subjects, 672 (69%) completed the survey. Asthma specialists were more likely to have an office spirometer (78% [216/277] vs. 43% [169/395], P <0.001) than were primary care physicians, and more likely to report measuring pulmonary function in at least 75% of their patients with asthma (83% [223/270] vs. 34% [131/388], P <0.001). In logistic regression analysis, factors most strongly associated with reported spirometry use (in at least 75% of patients) among asthma specialists were owning a spirometer, disagreeing with the statement that the test requires excessive use of office resources, and agreeing that spirometry is a necessary part of the asthma evaluation. Among primary care physicians, owning a spirometer, agreeing that the data are necessary for accurate diagnosis, and believing that they were trained to perform and interpret the test were most strongly associated with reported spirometry use. CONCLUSION: Pulmonary function testing is underutilized by physicians, with rates of utilization lowest among primary care physicians. Providing primary care physicians with better access to spirometry, through provision of a machine and appropriate training in its use and interpretation, may improve compliance with the NAEPP recommendations.     

The pulmonary outcome of long-term survivors after congenital diaphragmatic hernia repair

BACKGROUND: Congenital diaphragmatic hernia (CDH) represents a chronic condition with significant pulmonary and non-pulmonary complications. The main aim of the present study was to determine the pulmonary outcome in a group of long-term survivors of CDH. METHODS: Clinical records of 46 patients with CDH admitted to the University Children's Hospital Zurich between 1991 and 2001 were reviewed retrospectively. Survivors underwent clinical examination, lung function tests and measurements of exhaled nitric oxide. RESULTS: 30 of 46 (65%) patients survived after repair of CDH and 19 children participated in a follow-up study at the mean age of 7.9 (2.8) years. At least one wheezy episode requiring inhaled bronchodilators was reported by 9/19 (47%) children and 4/19 (21%) children complained of recurrent wheezy episodes. Nine children showed lung function impairment in spirometry as well as in oscillatory resistance. Neither duration of assisted ventilation nor the length of hospitalisation appeared to correlate with lung function. Exhaled nitric oxide was within normal range in our group of CDH survivors. Measurement of respiratory system resistance using a forced oscillation technique detected those CDH survivors, who showed abnormal pattern in spirometry. However, no correlation between oscillatory resistance and specific airway resistance measured by whole body plethysmography was found. CONCLUSIONS: Despite the presence of rather insignificant symptoms, we found mild to moderate pulmonary functional impairment in children surviving CDH repair.     

Assessing the relationship between lung cancer risk and emphysema detected on low-dose CT of the chest

RATIONALE: Identification of risk factors for lung cancer can help in selecting patients who may benefit the most from smoking cessation interventions, early detection, or chemoprevention. OBJECTIVE: To evaluate whether the presence of emphysema on low-radiation-dose CT (LDCT) of the chest is an independent risk factor for lung cancer. METHODS: The study used data from a prospective cohort of 1,166 former and current smokers participating in a lung cancer screening study. All individuals underwent a baseline LDCT and spirometry followed by yearly repeat LDCT studies. The incidence density of lung cancer among patients with and without emphysema on LDCT was estimated. Stratified and multiple regression analyses were used to assess whether emphysema is an independent risk factor for lung cancer after adjusting for age, gender, smoking history, and the presence of airway obstruction on spirometry. RESULTS: On univariate analysis, the incidence density of lung cancer among individuals with and without emphysema on LDCT was 25.0 per 1,000 person-years and 7.5 per 1,000 person-years, respectively (risk ratio [RR], 3.33; 95% confidence interval [CI], 1.41 to 7.85). Emphysema was also associated with increased risk of lung cancer when the analysis was limited to individuals without airway obstruction on spirometry (RR, 4.33; 95% CI, 1.04 to 18.16). Multivariate analysis showed that the presence of emphysema (RR, 2.51; 95% CI, 1.01 to 6.23) on LDCT but not airway obstruction (RR, 2.10; 95% CI, 0.79 to 5.58) was associated with increased risk of lung cancer after adjusting for potential cofounders. CONCLUSIONS: Results suggest that the presence of emphysema on LDCT is an independent risk factor for lung cancer.     

Lung function and respiratory health of long-term fiber-exposed stonewool factory workers.

The present study was undertaken to examine the respiratory health of a Danish workforce exposed to man-made vitreous fibers (MMVF) during production. Workers with more than 5 yr occupational exposure to MMVF (n = 377) were compared to a group without MMVF exposure (n = 381). Respiratory health was assessed by questionnaire, dynamic spirometry, and measurement of transfer factor. Overall response rate was 63%. A sample of nonresponders was assessed by questionnaire and spirometry. On most spirometric indices the two groups had comparable values. However, a larger proportion (14.5%) of the exposed subjects had an obstructive flow pattern compared with the control subjects (5.3%). Subgroup analyses showed that the elevated risk of airways obstruction associated with exposure was restricted to heavy smokers. Transfer factor and prevalences of symptoms and self-reported disease were similar in the two groups. There is no indication of excess risk of lung fibrosis. However, a number of exposed workers have some degree of airflow obstruction, which cannot be explained by known confounders. An additive or synergistic action between smoking and fiber exposure on airflow obstruction can be speculated.