Pierre-Olivier Bridevaux

Long-term decline in lung function, utilisation of care and quality of life in modified GOLD stage 1 COPD

Background: Little is known about the long-term outcomes of individuals with mild chronic obstructive pulmonary disease (COPD) as defined by the Global Initiative for Chronic Obstructive Lung Disease (GOLD). Methods: A population cohort of 6671 randomly selected adults without asthma was stratified into categories of modified GOLD-defined COPD (prebronchodilator spirometry). Further stratification was based on the presence or absence of respiratory symptoms. After 11 years, associations between baseline categories of COPD and decline in forced expiratory volume in 1 s (FEV1), respiratory care utilisation and quality of life as measured by the SF-36 questionnaire were examined after controlling for age, sex, smoking and educational status. Results: At baseline, modified GOLD criteria were met by 610 (9.1%) participants, 519 (85.1%) of whom had stage 1 COPD. At follow-up, individuals with symptomatic stage 1 COPD (n = 224) had a faster decline in FEV1 (−9 ml/year (95% CI −13 to −5)), increased respiratory care utilisation (OR 1.6 (95% CI 1.0 to 2.6)) and a lower quality of life than asymptomatic subjects with normal lung function (n = 3627, reference group). In contrast, individuals with asymptomatic stage 1 COPD (n = 295) had no significant differences in FEV1 decline (−3 ml/year (95% CI −7 to +1)), respiratory care utilisation (OR 1.05 (95% CI 0.63 to 1.73)) or quality of life scores compared with the reference group. Conclusions: In population-based studies, respiratory symptoms are of major importance for predicting long-term clinical outcomes in subjects with COPD with mild obstruction. Population studies based on spirometry only may misestimate the prevalence of clinically relevant COPD.

Traffic-Related Air Pollution Correlates with Adult-Onset Asthma among Never-Smokers

Background: Traffic-related pollution is associated with the onset of asthma in children. Its effect on adult-onset asthma is poorly investigated. The SAPALDIA cohort study was used to investigate associations between the 11-year change (1991–2002) in home outdoor traffic-related particulate matter up to 10 μm in diameter (TPM10) and the incidence of asthma. Methods: Never-smokers without asthma at baseline aged 18–60 years in 1991 were eligible for inclusion in the study. Subjects reporting doctor-diagnosed asthma at follow-up were considered incident cases. TPM10 at baseline and follow-up was predicted and interpolated to subjects’ place of residence by dispersion models using emission and meteorological data. Cox proportional hazard models for time to asthma onset were adjusted (age, gender, baseline atopy, body mass index, bronchial reactivity, maternal allergies). Results: Of 2725 never-smokers, 41 reported asthma onset in 2002. Home outdoor TPM10 concentrations improved during the interval (mean −0.6; range −9 to +7.2; IQR 0.6 μg/m3). The incidence of asthma was associated with a change in TPM10. The hazard ratio (1.30; 95% CI 1.05 to 1.61) per 1 μg/m3 change in TPM10 (IQR) was not sensitive to further adjustments (education, workplace exposure, passive smoking, parental asthma or allergies, random area effects, lung function or co-pollutants such as regional, secondary, total PM10 or proximity to busy roads). Conclusion: The data suggest a role for traffic-related pollution in adult-onset asthma. Space, time and source-specific individual assignment of exposure to traffic-related pollution is a key strength of SAPALDIA. It may explain why findings were statistically significant despite the limited number of new cases. As traffic-related pollution prevails, the finding may be of substantial public health relevance.

Adult lung function and long-term air pollution exposure. ESCAPE: a multicentre cohort study and meta-analysis

The chronic impact of ambient air pollutants on lung function in adults is not fully understood. The objective of this study was to investigate the association of long-term exposure to ambient air pollution with lung function in adult participants from five cohorts in the European Study of Cohorts for Air Pollution Effects (ESCAPE). Residential exposure to nitrogen oxides (NO2, NOx) and particulate matter (PM) was modelled and traffic indicators were assessed in a standardised manner. The spirometric parameters forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) from 7613 subjects were considered as outcomes. Cohort-specific results were combined using meta-analysis. We did not observe an association of air pollution with longitudinal change in lung function, but we observed that a 10 μg·m−3 increase in NO2 exposure was associated with lower levels of FEV1 (−14.0 mL, 95% CI −25.8 to −2.1) and FVC (−14.9 mL, 95% CI −28.7 to −1.1). An increase of 10 μg·m−3 in PM10, but not other PM metrics (PM2.5, coarse fraction of PM, PM absorbance), was associated with a lower level of FEV1 (−44.6 mL, 95% CI −85.4 to −3.8) and FVC (−59.0 mL, 95% CI −112.3 to −5.6). The associations were particularly strong in obese persons. This study adds to the evidence for an adverse association of ambient air pollution with lung function in adults at very low levels in Europe. The ESCAPE study finds that, even at very low levels, air pollution has adverse effects on lung function in adults http://ow.ly/A1ssB

Should pulmonary embolism be suspected in exacerbation of chronic obstructive pulmonary disease

Background: The cause of acute exacerbation of chronic obstructive pulmonary disease (COPD) is often difficult to determine. Pulmonary embolism may be a trigger of acute dyspnoea in patients with COPD. Aim: To determine the prevalence of pulmonary embolism in patients with acute exacerbation of COPD. Methods: 123 consecutive patients admitted to the emergency departments of two academic teaching hospitals for acute exacerbation of moderate to very severe COPD were included. Pulmonary embolism was investigated in all patients (whether or not clinically suspected) following a standardised algorithm based on d-dimer testing, lower-limb venous ultrasonography and multidetector helical computed tomography scan. Results: Pulmonary embolism was ruled out by a d-dimer value <500 μg/l in 28 (23%) patients and a by negative chest computed tomography scan in 91 (74%). Computed tomography scan showed pulmonary embolism in four patients (3.3%, 95% confidence interval (CI), 1.2% to 8%), including three lobar and one sub-segmental embolisms. The prevalence of pulmonary embolism was 6.2% (n = 3; 95% CI, 2.3% to 16.9%) in the 48 patients who had a clinical suspicion of pulmonary embolism and 1.3% (n = 1; 95% CI, 0.3% to 7.1%) in those not suspected. In two cases with positive computed tomography scan, the venous ultrasonography also showed a proximal deep-vein thrombosis. No other patient was diagnosed with venous thrombosis. Conclusions: The prevalence of unsuspected pulmonary embolism is very low in patients admitted in the emergency department for an acute exacerbation of their COPD. These results argue against a systematic examination for pulmonary embolism in this population.

Respiratory viruses in bronchoalveolar lavage: a hospital-based cohort study in adults

Background: The epidemiology of respiratory viruses and their potential clinical impact when recovered in lower respiratory specimens has not been established in the hospital setting. A study was performed to investigate the association between positive viral detection and respiratory infection in an at-risk population. Methods: 299 adult patients who underwent bronchoalveolar lavage (BAL) procedures were enrolled in a hospital-based prospective cohort study. Descriptive epidemiology is presented of 17 different respiratory viruses detected by reverse transcription-polymerase chain reaction assays in BAL fluid specimens. Multivariate analysis was conducted to identify the clinical characteristics independently associated with the presence of virus. Results: Of 522 BAL fluid specimens analysed, 81% were collected in adult transplant recipients or other immunocompromised patients. Overall, PCR assays identified viral nucleic acid in 91 BAL fluid samples (17.4%). Similar rates of virus-positive BAL fluid were found in the different subpopulations studied (p = 0.113). Coronaviruses were the most frequent (32.3%), followed by rhinovirus (22.6%), parainfluenza (19.5%), influenza (9.7%), respiratory synctial virus (8.6%), human metapneumovirus (4.2%) and bocavirus (3.1%). Multivariate analysis using mixed models showed that respiratory viral infections were associated with a lack of antibiotic treatment response (OR 2.2, 95% CI 1.2 to 4.1) and the absence of radiological infiltrate (OR 0.3, 95% CI 0.2 to 0.8). In lung transplant recipients in whom a respiratory infection was suspected, the respiratory viral detection rate was 24.4% compared with 13.8% overall in other patients (p = 0.02). Conclusions: In this cohort of hospitalised adults, respiratory viruses detected in BAL fluid specimens were associated with respiratory symptoms, absence of radiological infiltrates and a poor response to antibiotic therapy.

Occupational Exposure to Dusts, Gases, and Fumes and Incidence of Chronic Obstructive Pulmonary Disease in the Swiss Cohort Study on Air Pollution and Lung and Heart Diseases in Adults

RATIONALE There is limited evidence from population-based studies demonstrating incidence of spirometric-defined chronic obstructive pulmonary disease (COPD) in association with occupational exposures. OBJECTIVES We evaluated the association between occupational exposures and incidence of COPD in the Swiss Cohort Study on Air Pollution and Lung and Heart Diseases in Adults (SAPALDIA). MEASUREMENTS AND MAIN RESULTS Prebronchodilator ratio of forced expiratory volume in 1 second over forced vital capacity (FEV(1)/FVC) was measured in 4,267 nonasthmatic SAPALDIA participants ages 18-62 at baseline in 1991 and at follow-up in 2001-2003. COPD was defined by the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criterion (FEV(1)/FVC < 0.70) and Quanjer reference equation (FEV(1)/FVC < lower limit of normal [LLN]), and categorized by severity (≥ 80% and <80% predicted FEV(1) for stage I and stage II+, respectively). Using a job-exposure matrix, self-reported occupations at baseline were assigned exposures to biological dusts, mineral dusts, gases/fumes, and vapors, gases, dusts, or fumes (VGDF) (high, low, or unexposed as reference). Adjusted incident rate ratios (IRRs) of stage I and stage II+ COPD were estimated in mixed Poisson regression models. Statistically significant (P < 0.05) IRRs of stage II+ GOLD and LLN-COPD, indicating risks between two- and fivefold, were observed for all occupational exposures at high levels. Occupational exposure-associated risk of stage II+ COPD was observed mainly in males and ages ≥ 40 years, and remained elevated when restricted to nonsmokers. CONCLUSIONS In a Swiss working adult population, occupational exposures to biological dusts, mineral dusts, gases/fumes, and VGDF were associated with incidence of COPD of at least moderate severity.

Impact of road traffic noise annoyance on health-related quality of life: results from a population-based study

PurposeTo estimate the impact of traffic-related noise annoyance on health-related quality of life (HrQoL) in a population-based study and potential effect modification by gender.MethodsThe study included 5,021 participants of the Swiss Cohort Study of Air Pollution and Lung Disease in Adults second survey. The association between traffic-related noise annoyance, measured on an 11-point scale, and HrQoL, based on SF-36 scores, was investigated by multivariate regression analysis. Effect sizes were calculated, and interactions by gender and chronic disease status examined.ResultsThirteen percentage of the study population reported high annoyance due to traffic. Women were more likely to report high noise annoyance (adjOR 1.23; 95%CI 1.01–1.48). Except for general health, all SF-36 scores showed a significant negative association with noise annoyance. The respective effect sizes ranged between 0.13 and 0.54. Significant effect modification by gender and chronic disease status was present in specific SF-36 domains.ConclusionThis paper presents first evidence of an inverse relationship of noise annoyance and HrQoL in a general population. Although the estimated effects are small to moderate for individuals, they may add up to a relevant public health impact.

Respiratory viruses in lung transplant recipients: a critical review and pooled analysis of clinical studies.

Lung transplant recipients present an increased risk for severe complications associated with respiratory infections. We conducted a review of the literature examining the clinical relationship between viral respiratory infection and graft complications. Thirty‐four studies describing the clinical impact of influenza, respiratory syncytial virus, parainfluenza, human metapneumovirus, rhinovirus, enterovirus, coronavirus, bocavirus or adenovirus were identified. The detection rate of respiratory viral infection ranged from 1.4% to 60%. Viruses were detected five times more frequently when respiratory symptoms were present [odds ratio (OR) = 4.97; 95% CI = 2.11–11.68]. Based on available observations, we could not observe an association between respiratory viral infection and acute rejection (OR = 1.35; 95% CI = 0.41–4.43). We found a pooled incidence of 18% (9/50) of bronchiolitis obliterans syndrome (BOS) in virus‐positive cases compared to 11.6% (37/319) in virus‐negative cases; however, limited number of BOS events did not allow to confirm the association. Our review confirms a causal relationship between respiratory viruses and respiratory symptoms, but cannot confirm a link between respiratory viruses and acute lung rejection. This is related in part to the heterogeneity and limitations of available studies. The link with BOS needs also to be reassessed in appropriate prospective studies.

Titrated sedation with propofol or midazolam for flexible bronchoscopy: a randomised trial

In this study, we questioned whether propofol provided clinical benefits compared with midazolam in terms of neuropsychometric recovery, safety profile and patient tolerance. Patients, aged >18 yrs, were randomised to receive midazolam or propofol, given by non-anaesthetist physicians to achieve moderate levels of sedation as assessed by the electroencephalographic bispectral index (BIS; between 70 and 85). The primary end-point was the time delay until recovery of the BIS above 90. Other end-points included a neuropsychometric continuous performance test (CPT), serious respiratory adverse events, patient tolerance and physician satisfaction. Neuropsychometric recovery was improved in the propofol compared to the midazolam group as evidenced by faster normalisation of BIS index (5.4±4.7 min versus 11.7±10.2 min; p = 0.001) and better results at the CPT. In the midazolam group, 15% of patients presented profound sedation precluding CPT completion and one patient required mechanical ventilatory support. Patient tolerance was significantly better in the propofol group, whereas the operator’s assessment was comparable in both groups. Compared with midazolam, propofol provided a higher quality of sedation in terms of neuropsychometric recovery and patient tolerance. BIS-guided propofol administration represents a safe sedation technique that can be performed by the non-anaesthesiologist.

Prevalence of airflow obstruction in smokers and never-smokers in Switzerland

The aim of the present study was to measure age-specific prevalence of airflow obstruction in Switzerland in smokers and never-smokers using pulmonary function tests and respiratory symptoms from 6,126 subjects participating in the Swiss Cohort Study on Air Pollution and Lung Diseases in Adults. The lower limit of normal of the forced expiratory volume in 1 s/forced vital capacity ratio was used to define airflow obstruction. Severity of airflow obstruction was graded according to the recommendations of the Global Initiative for Chronic Obstructive Lung Disease. Prevalence of airflow obstruction ranged from 2.5% in subjects aged 30–39 yrs to 8.0% in those aged ≥70 yrs. In multivariate analysis, age (OR 2.8, ≥70 yrs versus 30–39 yrs), smoking (OR 1.8) and asthma (OR 6.7) were associated with airflow obstruction. Never-smokers constituted 29.3% of subjects with airflow obstruction. Never-smokers with airflow obstruction were younger, more likely to be male and reported asthma more frequently than obstructive smokers. Obstructive smokers and never-smokers had similar level of symptoms and quality of life impairment. The prevalence of airflow obstruction in Switzerland is similar to other developed countries. Never-smokers account for a third of the prevalence, which is higher proportion than elsewhere. Airflow obstruction in never-smokers deserves attention because of its frequency and its similar health impact to that in smokers.