Antoni Ferrer

Identification and prospective validation of clinically relevant chronic obstructive pulmonary disease (COPD) subtypes

Background Chronic obstructive pulmonary disease (COPD) is increasingly considered a heterogeneous condition. It was hypothesised that COPD, as currently defined, includes different clinically relevant subtypes. Methods To identify and validate COPD subtypes, 342 subjects hospitalised for the first time because of a COPD exacerbation were recruited. Three months after discharge, when clinically stable, symptoms and quality of life, lung function, exercise capacity, nutritional status, biomarkers of systemic and bronchial inflammation, sputum microbiology, CT of the thorax and echocardiography were assessed. COPD groups were identified by partitioning cluster analysis and validated prospectively against cause-specific hospitalisations and all-cause mortality during a 4 year follow-up. Results Three COPD groups were identified: group 1 (n=126, 67 years) was characterised by severe airflow limitation (postbronchodilator forced expiratory volume in 1 s (FEV1) 38% predicted) and worse performance in most of the respiratory domains of the disease; group 2 (n=125, 69 years) showed milder airflow limitation (FEV1 63% predicted); and group 3 (n=91, 67 years) combined a similarly milder airflow limitation (FEV1 58% predicted) with a high proportion of obesity, cardiovascular disorders, diabetes and systemic inflammation. During follow-up, group 1 had more frequent hospitalisations due to COPD (HR 3.28, p<0.001) and higher all-cause mortality (HR 2.36, p=0.018) than the other two groups, whereas group 3 had more admissions due to cardiovascular disease (HR 2.87, p=0.014). Conclusions In patients with COPD recruited at their first hospitalisation, three different COPD subtypes were identified and prospectively validated: ‘severe respiratory COPD’, ‘moderate respiratory COPD’, and ‘systemic COPD’.

The use of respiration indices in the composting process: a review

Respiration is directly related to the metabolic activity of a microbial population. Micro-organisms respire at higher rates in the presence of large amounts of bioavailable organic matter while respiration rate is slower if this type of material is scarce. In the composting process respiration activity has become an important parameter for the determination of the stability of compost. It is also used for the monitoring of the composting process and it is considered an important factor for the estimation of the maturity of the material. A wide range of respirometric protocols has been reported based either on CO2 production, O2 uptake or release of heat. The most common methods are those based on O2 uptake. Respirometric assays are affected by a number of parameters including temperature, humidity, and both incubation and pre-incubation conditions. Results from respirometries are generally expressed as ‘respiration indices’, most of them with their own units and basis. In consequence, some confusion exists when referring and comparing respiration indices. This is particularly important because current and future legislations define and measure the biological stability of waste on the basis of respiration activity of the material. This paper discusses and compares most common respiration indices currently used.

Expiratory muscle endurance in chronic obstructive pulmonary disease

Background: A reduction in expiratory muscle (ExM) endurance in patients with chronic obstructive pulmonary disease (COPD) may have clinically relevant implications. This study was carried out to evaluate ExM endurance in patients with COPD. Methods: Twenty three patients with COPD (FEV1 35 (14)% predicted) and 14 matched controls were studied. ExM endurance was assessed using a method based on the use of an expiratory threshold valve which includes two steps. In step 1 the load is progressively increased (50 g every 2 minutes) until task failure is reached, and the pressure generated against the highest tolerated load is defined as the maximal expiratory sustainable pressure (Pthmax). In step 2 subjects breathe against a submaximal constant load (80% of Pthmax) and the time elapsed until task failure is termed the expiratory endurance time (Tth80). In addition, the strength of peripheral muscles (handgrip, HGS) and respiratory muscles (maximal inspiratory and expiratory pressures, Pimax and Pemax, respectively) was evaluated. Results: Patients with COPD had lower ExM strength and endurance than controls: Pemax 64 (19)% predicted v 84 (14)% predicted (mean difference 20%; 95% confidence intervals (CI) 14 to 39); Pthmax 52 (27) v 151 (46) cm H2O (mean difference 99, 95% CI 74 to 123); and Tth80 9.4 (6.3) v 14.2 (7.4) min (mean difference 4.8, 95% CI 1.0 to 10.4; p<0.01 for all). Interestingly, ExM endurance directly correlated with both the severity of airways obstruction (Pthmax with FEV1, r=0.794, p<0.01) and the reduction in strength observed in different muscle groups (Pthmax with HG, Pimax or Pemax, r=0.550, p<0.05; r=0.583, p<0.001; and r=0.584, p<0.001, respectively). Conclusions: ExM endurance is decreased in patients with COPD. This impairment is proportional to the severity of the disease and is associated with lower strength in different muscle groups. This suggests that systemic effects are implicated in the impairment observed in ExM function.

Physical activity in COPD patients: patterns and bouts

The present study aims to describe the pattern of physical activity and the frequency, duration and intensity of physical activity bouts in patients with chronic obstructive pulmonary disease (COPD), to assess how these patterns differ according to COPD severity, and to explore whether these patients meet the general guidelines for physical activity for older adults. 177 patients (94% male, mean±sd age 71±8 years and forced expiratory volume in 1 s 52±16% predicted) wore the SenseWear Pro2 Armband accelerometer for eight consecutive days. Physical activity bouts were defined as periods of ≥10 min above 1.5 metabolic equivalent tasks and classified according to their median intensity. Patients engaged in activity a median of 153 min·day−1 and 57% of that time was spent in bouts. Median frequencies of bouts per day were four and three for all and moderate-to-vigorous intensities, respectively. With increasing COPD severity, time in physical activity, proportion of time in bouts and frequency of bouts decreased. 61% of patients fulfilled the recommended physical activity guidelines. In conclusion, COPD patients of all spirometric severity stages engage in physical activity bouts of moderate-to-vigorous intensities. Patients with severe and very severe COPD perform their daily activities in fewer and shorter bouts than those in mild and moderate stages. Patients with severe COPD perform their daily activities in fewer, shorter bouts than those in mild and moderate stages http://ow.ly/nug7k

Diagnosis and treatment of sleep apnea-hypopnea syndrome

a Unidad del Sueno, Servicio de Neumologia, Hospital Vall d’Hebron, Barcelona, Spain, (Ciberes) b Unidad Multidisciplinar de Trastornos del Sueno, Hospital Txagorritxu, Vitoria, Spain, (Ciberes) c Unidad de Neumologia, Hospital de Requena, Valencia, Spain, (Ciberes) d Servicio de Neumologia, Hospital Universitario Miguel Servet, IACS, Zaragoza, Spain, (Ciberes) e Servei de Pneumologia, Hospital del Mar-IMIM, Hospital de Sabadell, UPF, UAB, Barcelona, Spain, (Ciberes) f Servicio de Neumologia, Hospital San Pedro de Alcantara, Caceres, Spain, (Ciberes) g Servei de Pneumologia, Hospital Universitari Sagrat Cor, UB, Barcelona, Spain, (Ciberes) h Unidad de Sueno, Hospital Universitario Complejo Asistencial de Burgos, Spain, (Ciberes) i Servicio de Neumologia, Hospital Universitario Complejo Asistencial de Burgos, Spain, (Ciberes)

Characteristics of patients admitted for the first time for COPD exacerbation

BACKGROUND This study describes the characteristics of a large sample of patients hospitalised for the first time for a chronic obstructive pulmonary disease (COPD) exacerbation. METHODS All subjects first admitted for a COPD exacerbation to nine teaching Spanish hospitals during January 2004-March 2006, were eligible. COPD diagnosis was confirmed by spirometry under stability. At admission, sociodemographic data, lifestyle, previous treatment and diagnosis of respiratory disease, lung function and Charlson index of co-morbidity were collected. A comprehensive assessment, including dyspnea, lung function, six-minute walking test, and St. Georges Respiratory Questionnaire (SGRQ), was completed 3 months after admission, during a clinically stable disease period. RESULTS Three-hundred and forty-two patients (57% of the eligible) participated in the study: 93% males, mean (SD) age 68 (9) years, 42% current smokers, 50% two or more co-morbidities, 54% mild-to-moderate dyspnea, post-bronchodilator FEV(1) 52 (16)% of predicted (54% mild-to-moderate COPD in ATS/ERS stages), 6-min walking distance 440 m, total SGRQ score 37 (18), and 36% not report respiratory disease. The absence of a previous COPD diagnosis, positive bronchodilator test, female gender, older age, higher DLco and higher BMI were independently associated with less severe COPD. CONCLUSIONS We show that the patients admitted after presenting with their first COPD exacerbation have a wide range of severity, with a large proportion of patients in the less advanced COPD stages.

La heterogeneidad fenotípica de la EPOC

A functional definition of chronic obstructive pulmonary disease (COPD) based on airflow limitation has largely dominated the field. However, a view has emerged that COPD involves a complex array of cellular, organic, functional, and clinical events, with a growing interest in disentangling the phenotypic heterogeneity of COPD. The present review is based on the opinion of the authors, who have extensive research experience in several aspects of COPD. The starting assumption of the review is that current knowledge on the pathophysiology and clinical features of COPD allows us to classify phenotypic information in terms of the following dimensions: respiratory symptoms and health status, acute exacerbations, lung function, structural changes, local and systemic inflammation, and systemic effects. Twenty-six phenotypic traits were identified and assigned to one of the 6 dimensions. For each dimension, a summary is provided of the best evidence on the relationships among phenotypic traits, in particular among those corresponding to different dimensions, and on the relationship between these traits and relevant events in the natural history of COPD. The information has been organized graphically into a phenotypic matrix where each cell representing a pair of phenotypic traits is linked to relevant references. The information provided has the potential to increase our understanding of the heterogeneity of COPD phenotypes and help us plan future studies on aspects that are as yet unexplored.

Dietary habits of firstly admitted Spanish COPD patients.

BACKGROUND & AIMS We described dietary habits in a Spanish sample of COPD patients and assessed its adequacy according to dietary recommendations, which so far have never been published. METHODS 275 patients hospitalized for the first time for a COPD exacerbation in Spain answered a 122-item food frequency questionnaire on their last 2 years dietary habits. A Spanish food composition table was used to estimate nutrient intake. Adequacy of dietary intakes was assessed using the Spanish Nutrition Society guidelines for the elderly. RESULTS Mean(SD) age was 68(8)years, 93% males, 32% current smokers, and post-bronchodilator FEV(1) 53(16)% predicted. Mean(SD) body mass index was 28(5)kg/m2, with only 2% of subjects under 20kg/m2. Mean intake of meat, poultry and eggs was slightly higher (mean 108g/d) than recommended. Fish and shellfish (86g/d) as well as fruit and vegetables (567g/d) were adequate. Mean energy intake was 2033kcal/d. The proportion of energy from carbohydrates was lower (39%) whereas that from proteins and lipids were higher than recommended (20% and 35%, respectively). Alcohol intake was <30g in 80% of patients. Fatty acids, vitamin and mineral intakes were adequate, except for a deficiency in vitamin D (4.5microg/d). Stratification by socio-demographic and clinical characteristics showed very similar results. CONCLUSIONS Moderate-to-severe Spanish COPD patients report an adequate intake of the main food groups and macro- and micro-nutrients according to local recommendations, excepting vitamin D.

Air pollution and biomarkers of systemic inflammation and tissue repair in COPD patients

The origin(s) of systemic inflammation in patients with chronic obstructive pulmonary disease (COPD) is unclear. We investigated the impact of exposure to ambient air pollution on systemic biomarkers of inflammation (C-reactive protein (CRP), tumour necrosis factor-&agr;, interleukin (IL)-6, IL-8 and fibrinogen) and tissue repair (hepatocyte growth factor (HGF)) in 242 clinically stable COPD patients (mean age 67.8 years and forced expiratory volume in 1 s 71.3% predicted) in Barcelona, Spain, in 2004–2006. A spatiotemporal exposure assessment framework was applied to predict ambient nitrogen dioxide (NO2) and levels of particles with a 50% cut-off aerodynamic diameter of 2.5 &mgr;m (PM2.5) at each participant’s home address during 10 periods of 24 h (lags 1–10) and 1 year prior to the blood sampling date. We used linear regression models to estimate associations between biomarkers and exposure levels. An interquartile range (IQR) increase in NO2 exposure in lag 5 was associated with 51%, 10% and 9% increases in CRP, fibrinogen and HGF levels respectively. We also observed 12% and 8% increases in IL-8 associated with an IQR increase in NO2 exposure in lag 3 and over the year before sampling, respectively. These increases were larger in former smokers. The results for PM2.5 were not conclusive. These results show that exposure to ambient NO2 increases systemic inflammation in COPD patients, especially in former smokers. NO2 exposure increases levels of systemic inflammation biomarkers in COPD patients, especially in former smokers http://ow.ly/sRKnX

Benefits of physical activity on COPD hospitalisation depend on intensity

The present study aims to disentangle the independent effects of the quantity and the intensity of physical activity on the risk reduction of chronic obstructive pulmonary disease (COPD) hospitalisations. 177 patients from the Phenotype Characterization and Course of COPD (PAC-COPD) cohort (mean±sd age 71±8 years, forced expiratory volume in 1 s 52±16% predicted) wore the SenseWear Pro 2 Armband accelerometer (BodyMedia, Pittsburgh, PA, USA) for eight consecutive days, providing data on quantity (steps per day, physically active days and daily active time) and intensity (average metabolic equivalent tasks) of physical activity. Information on COPD hospitalisations during follow-up (2.5±0.8 years) was obtained from validated centralised datasets. During follow-up 67 (38%) patients were hospitalised. There was an interaction between quantity and intensity of physical activity in their effects on COPD hospitalisation risk. After adjusting for potential confounders in the Cox regression model, the risk of COPD hospitalisation was reduced by 20% (hazard ratio (HR) 0.79, 95% CI 0.67–0.93; p=0.005) for every additional 1000 daily steps at low average intensity. A greater quantity of daily steps at high average intensity did not influence the risk of COPD hospitalisations (HR 1.01, p=0.919). Similar results were found for the other measures of quantity of physical activity. Greater quantity of low-intensity physical activity reduces the risk of COPD hospitalisation, but high-intensity physical activity does not produce any risk reduction. Greater quantity of low-intensity physical activity reduces the risk of COPD hospitalisation http://ow.ly/Oe2RE