Household air pollution and COPD: cause and effect or confounding by other aspects of poverty?

SETTING: Household air pollution (HAP) and chronic obstructive pulmonary disease (COPD) are both major public health problems, reported to cause around 4 million and 3 million deaths every year, respectively. The great majority of these deaths, as well as the burden of disease during life is felt by people in low- and middle-income countries (LMICs).OBJECTIVE and DESIGN: The extent to which HAP causes COPD is controversial; we therefore undertook this review to offer a viewpoint on this from the Global Initiative for COPD (GOLD).RESULTS: We find that while COPD is well-defined in many studies on COPD and HAP, there are major limitations to the definition and measurement of HAP. It is thus difficult to disentangle HAP from other features of poverty that are themselves associated with COPD. We identify other limitations to primary research studies, including the use of cross-sectional designs that limit causal inference.CONCLUSION: There is substantial preventable morbidity and mortality associated with HAP, COPD and poverty, separately and together. Although it may not be possible to define clear causal links between HAP and COPD, there is a clear urgency to reduce the avoidable burden of disease these inflict on the world´s poor.

The GOLD Summit on chronic obstructive pulmonary disease in low- and middle-income countries.

Chronic obstructive pulmonary disease (COPD) is one of the top three causes of death worldwide, but governments and non-governmental organisations have not given its prevention and treatment the priority it requires. This is particularly true in low- and middle-income countries, where most of the people suffering from this disease live. The United Nations (UN) has targeted a reduction of premature deaths from non-communicable diseases (NCDs) by a third by 2030; however, a coordinated UN/World Health Organization (WHO) strategy to address the burden of COPD (one of the most important NCDs) is still lacking. To explore the extent of the problem and inform the development of policies to improve the situation, the Board of Directors of the Global Initiative for Chronic Obstructive Lung Disease (GOLD) held a 1-day Summit. The key themes that emerged were the need to ensure accurate data on prevalence, raise awareness of the disease among the public, healthcare professionals and governments, including the fact that COPD aetiology goes beyond smoking (and other inhaled pollutants) and includes poor lung development in early life, and ensure that spirometry and both pharmacological and non-pharmacological therapies are available and affordable. Here, we present the actions that must be taken to address the impact of COPD. We believe that the WHO is particularly well-positioned to co-ordinate an attack on COPD, and GOLD will do all it can to help and rally support.

Respiratory medication use in primary care among COPD subjects in four Latin American countries.

OBJECTIVES: To assess respiratory medications used, factors predicting treatment and patterns of corticosteroid (CS) use in primary care in Latin America among chronic obstructive pulmonary disease (COPD) patients. METHODS: COPD was defined as post-bronchodilator forced expiratory volume in 1 s/forced vital capacity (FEV1/FVC) < 0.70 or previous medical diagnosis. To determine factors associated with respiratory medication use, crude and adjusted Poisson regression models were performed. RESULTS: Of 1743 patients interviewed, 1540 completed spirometry, 309 had COPD (FEV1/FVC<0.70) and 102 had a prior diagnosis of COPD. Among spirometry-defined COPD patients, 36.6% used respiratory medications: bronchodilators (BD) 24.9%, CS 13.3%, BD+CS 15.2%. In those with a previous diagnosis, 79.4% used respiratory medications: BD 64.7%, CS 37.6%, BD+CS 25.6%. A total of 81/102 (79%) patients with prior diagnosis were using CS despite not having airway obstruction or exacerbation. In spirometry-defined COPD, dyspnoea (OR 2.09, 95%CI 1.13-3.87), severe airway obstruction (OR 3.36, 95%CI 1.40-8.03) and exacerbation in the past year (OR 5.52, 95%CI 2.19-13.89) were associated with increased respiratory medication use. Among those with a previous diagnosis, use of respiratory medications was associated with cough (OR 5.31, 95%CI 1.28-22.12), severe airway obstruction (OR 29.50, 95%CI 3.18-273.30) and fewer years of schooling (OR 0.12, 95%CI 0.03-0.52). CONCLUSIONS: In the primary care setting, undertreatment is frequent in spirometry-defined COPD patients, and there is increased use of CS (overtreatment) in patients with a previous diagnosis of COPD.

Photodynamic properties and photoinactivation of Candida albicans mediated by brominated derivatives of triarylmethane and phenothiazinium dyes.

The photodynamic activity of brominated derivatives of New Fuchsin and Azure B was studied in solution and in cell suspensions of Candida albicans. The spectroscopic and photodynamic properties of these photosensitizers were compared with those of Crystal Violet and Azure B, which represent active photosensitizer related to each family of compounds. Triarylmethane derivatives absorb intensely with a band centered at ∼ 570 nm, while the phenothiazinium dyes at ∼ 650 nm. Photooxidation of 9,10-dimethylanthracene was observed using phenothiazinium compounds indicating the formation of singlet molecular oxygen, while it was not detected using triarylmethane agents. However, triarylmethane dyes were able to photooxidize l-tryptophan. In yeast cell suspensions, the photosensitized inactivation of C. albicans increases with photosensitizer concentration, causing a ∼ 5 log decrease of cell survival, when the cultures are treated with 20 µM of Crystal Violet and irradiated for 60 min. Under these conditions, the photodynamic activity of 50 µM Azure B induced a ∼ 3 log decrease of cell survival. Studies of photodynamic action mechanism indicated that photoinactivation of C. albicans cells induced by triarylmethane compounds involves mainly type I photoprocess. Although, phenothiazinium derivatives produce singlet molecular oxygen, a contribution of other reactive oxygen species cannot be discarded in the photoinactivation of C. albicans.

Paid employment in subjects with and without chronic obstructive pulmonary disease in five Latin American cities: the PLATINO study.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a costly condition that frequently causes permanent work disabilities. Little information exists regarding the impact of COPD on work force participation and the indirect costs of the disease in developing countries. OBJECTIVE: To examine the frequency of paid employment and factors influencing it in a Latin-American population-based study. METHODS: Post-bronchodilator FEV(1)/FVC < 0.70 (forced expiratory volume in 1 s/forced vital capacity) was used to define COPD. Information regarding paid work was assessed by the question 'At any time in the past year, have you worked for payment?' RESULTS: Interviews were conducted with 5571 subjects; 5314 (759 COPD and 4554 non-COPD) subjects underwent spirometry. Among the COPD subjects, 41.8% reported having paid work vs. 57.1% of non-COPD (P < 0.0001). The number of months with paid work was reduced in COPD patients (10.5 ± 0.17 vs. 10.9 ± 0.06, P < 0.05). The main factors associated with having paid work in COPD patients were male sex (OR 0.33, 95%CI 0.23-0.47), higher education level (OR 1.05, 95%CI 1.01-1.09) and younger age (OR 0.90, 95%CI 0.88-0.92). COPD was not a significant contributor to employment (OR 0.83, 95%CI 0.69-1.00, P = 0.054) in the entire population. CONCLUSIONS: Although the proportion of persons with paid work is lower in COPD, having COPD appears not to have a significant impact on obtaining paid employment in the overall population of developing countries.

The 6-min walk distance in healthy subjects: reference standards from seven countries.

The 6-min walk distance (6MWD) predicted values have been derived from small cohorts mostly from single countries. The aim of the present study was to investigate differences between countries and identify new reference values to improve 6MWD interpretation. We studied 444 subjects (238 males) from seven countries (10 centres) ranging 40-80 yrs of age. We measured 6MWD, height, weight, spirometry, heart rate (HR), maximum HR (HR(max)) during the 6-min walk test/the predicted maximum HR (HR(max) % pred), Borg dyspnoea score and oxygen saturation. The mean ± sd 6MWD was 571 ± 90 m (range 380-782 m). Males walked 30 m more than females (p < 0.001). A multiple regression model for the 6MWD included age, sex, height, weight and HR(max) % pred (adjusted r² = 0.38; p < 0.001), but there was variability across centres (adjusted r² = 0.09-0.73) and its routine use is not recommended. Age had a great impact in 6MWD independent of the centres, declining significantly in the older population (p < 0.001). Age-specific reference standards of 6MWD were constructed for male and female adults. In healthy subjects, there were geographic variations in 6MWD and caution must be taken when using existing predictive equations. The present study provides new 6MWD standard curves that could be useful in the care of adult patients with chronic diseases.

Sex-related differences in COPD in five Latin American cities: the PLATINO study.

There is evidence to suggest sex differences exists in chronic obstructive pulmonary disease (COPD) clinical expression. We investigated sex differences in health status perception, dyspnoea and physical activity, and factors that explain these differences using an epidemiological sample of subjects with and without COPD. PLATINO is a cross-sectional, population-based study. We defined COPD as post-bronchodilator forced expiratory volume in 1 s/forced vital capacity ratio <0.70, and evaluated health status perception (Short Form (SF)-12 questionnaire) and dyspnoea (Medical Research Council scale). Among 5,314 subjects, 759 (362 females) had COPD and 4,555 (2,850 females) did not. In general, females reported more dyspnoea and physical limitation than males. 54% of females without COPD reported a dyspnoea score ≥ 2 versus 35% of males. A similar trend was observed in females with COPD (63% versus 44%). In the entire study population, female sex was a factor explaining dyspnoea (OR 1.60, 95%CI 1.40-1.84) and SF-12 physical score (OR -1.13, 95%CI -1.56- -0.71). 40% of females versus 28% of males without COPD reported their general health status as fair-to-poor. Females with COPD showed a similar trend (41% versus 34%). Distribution of COPD severity was similar between sexes, but currently smoking females had more severe COPD than currently smoking males. There are important sex differences in the impact that COPD has on the perception of dyspnoea, health status and physical activity limitation.

Chronic antigenic stimuli as a possible explanation for the immunodepression caused by liver cirrhosis.

The objectives of this work were the analysis of the functional characteristics of circulating monocytes and T lymphocytes in patients with liver cirrhosis, and evaluation of the relationship with an increased exposure to antigens due to bacterial translocation. Forty patients with liver cirrhosis (20 with compensated cirrhosis and 20 with ascitic decompensation) and 20 healthy control subjects were studied. Bacterial translocation was evaluated by serum levels of lipopolysaccharide binding protein (LBP). Macrophage activation was studied by CD40 antigen expression. T lymphocytes were analysed for activation (CD25(+), CD122(+)), effector function (CD8(+)CD45RO(+)CD57(+)), apoptosis (CD95(+)) and regulatory abilities, either by analysis of the membrane expression of co-stimulatory molecules CD80, CD86 and CD28, or by quantification of regulatory T cells CD4(+)CD25(high)forkhead box P3 (FoxP3). The percentage of activated monocytes and T lymphocytes in patients was increased significantly. The proportions of effector senescent cells and of those near to apoptosis were also significantly higher. With respect to these proportions, there were no significant differences between patients in function of the presence or absence of decompensation or in function of the increased or normal values of LBP. Conversely, those patients with elevated levels of LBP presented a significantly higher frequency of regulatory T cells than those with normal levels. In conclusion, patients with liver cirrhosis showed an intensive activation state with a higher percentage of cells committed to activation-induced death, even in non-advanced stages. It is possible that bacterial permeability and endotoxaemia contribute to the expansion of those lymphocyte populations implicated in the prevention of a more severe antigen-induced immunopathology.

Health-related quality of life in patients with primary Sjögren's syndrome: relationship with serum levels of proinflammatory cytokines.

OBJECTIVE: A cross-sectional study of 30 patients with primary Sjögren's syndrome (pSS) was performed to analyse the health-related quality of life and its relationship with serum levels of macrophage- and lymphocyte-derived cytokines. PATIENTS AND METHODS: Health-related quality of life was evaluated using the 36-item Short Form Health Survey (SF-36). Serum levels of interleukin (IL)-1beta, IL-6, IL-10, tumour necrosis factor (TNF)-alpha, and gamma-interferon (gamma-INF) were analysed by a sandwich immunoassay-based protein array system. RESULTS: Each of the eight scales of the SF-36 evaluating quality of life, as well as the physical composite score (PCS) and the mental composite score (MCS), showed a decrease in pSS patients. Similarly, patients with pSS showed significantly increased concentrations of each of the five cytokines analysed, when compared with the healthy control group (n = 20). In pSS patients, a significant negative correlation was detected between serum levels of IL-6 and the PCS of the SF-36. Those patients with concentrations of IL-6 higher than those of the healthy controls showed a significantly lower score in the dimensions of bodily pain and physical functioning, and in the PCS. CONCLUSIONS: Patients with pSS showed increased levels of several macrophage- and lymphocyte-derived cytokines, indicating the existence of an immune activation state. Serum levels of one of these cytokines, IL-6, were correlated with poor quality of life in these individuals.

Implications of immunomodulatory interleukins for the hyperimmunoglobulinemia of Sjögren's syndrome.

A prospective study of 37 patients with pSS and 20 healthy controls was performed to analyze the differences in circulating levels of macrophage-derived and Th1/Th2 cytokines which could explain the hyperimmunoglobulinemia, characteristic of primary Sjögren's syndrome (pSS). Serum levels of interleukin (IL)-6, IL-10, IL-12, gamma-interferon (gamma-INF) and IL-4 were analyzed by a sandwich immunoassay-based protein array system. When compared with the control group, higher levels of IL-6, IL-12 and IL-10 and a lower Th1/Th2 ratio, as demonstrated by the gamma-INF/IL-4 ratio, were detected in patients. The levels of IL-4 were notably higher in pSS patients with monoclonal gammopathy. Serum IL-4 and IL-10 levels and immunoglobulin G concentrations were significantly correlated. In conclusion, patients with pSS show a state of macrophage and T-lymphocyte activation with increased concentrations of cytokines implicated in the differentiation of B cells and secretion of immunoglobulins.

Sex differences in mortality in patients with COPD.

Little is known about survival and clinical prognostic factors in females with chronic obstructive pulmonary disease (COPD). The aim of the present study was to determine the survival difference between males and females with COPD and to compare the value of the different prognostic factors for the disease. In total, 265 females and 272 males with COPD matched at baseline by BODE (body mass index, airflow obstruction, dyspnoea, exercise capacity) and American Thoracic Society/European Respiratory Society/Global Initiative of Chronic Obstructive Lung Disease criteria were prospectively followed. Demographics, lung function, St George's Respiratory Questionnaire, BODE index, the components of the BODE index and comorbidity were determined. Survival was documented and sex differences were determined using Kaplan-Meier analysis. The strength of the association of the studied variables with mortality was determined using multivariate and receiver operating curves analysis. All-cause (40 versus 18%) and respiratory mortality (24 versus 10%) were higher in males than females. Multivariate analysis identified the BODE index in females and the BODE index and Charlson comorbidity score in males as the best predictors of mortality. The area under the curve of the BODE index was a better predictor of mortality than the forced expiratory volume in one second for both sexes. At similar chronic obstructive pulmonary disease severity by BODE index and forced expiratory volume in one second, females have significantly better survival than males. For both sexes the BODE index is a better predictor of survival than the forced expiratory volume in one second.

Worldwide burden of COPD in high- and low-income countries. Part II. Burden of chronic obstructive lung disease in Latin America: the PLATINO study.

SETTING: Five Latin American cities: São Paulo, Brazil; Mexico City, Mexico; Montevideo, Uruguay; Santiago, Chile; Caracas, Venezuela. OBJECTIVE: To describe the burden of chronic obstructive pulmonary disease (COPD) in Latin America. DESIGN: This is a multicentre study. Post-bronchodilator spirometry was used and the main outcome measure was FEV(1)/FVC < 0.7 (fixed ratio criterion). Global Obstructive Lung Disease (GOLD) stages were also analysed. RESULTS: The combined population aged > or =40 years in the five countries included in the study was approximately 85.3 million. Of these, it was estimated that 12.2 million have airflow obstruction, which corresponds to our prevalence estimate of 14.3%. The proportion of subjects in Stages II-IV of the GOLD classification was 5.6%. Risk factors presenting the highest aetiological fractions for COPD were age, current smoking, indoor exposure to coal and exposure to dust in the workplace. Smoking, the modifiable factor with the strongest aetiological fraction for COPD, affects 29.2% of adults aged > or =40 years in these cities, corresponding to approximately 25 million smokers in this age group. CONCLUSION: Prevention of smoking and exposure to pollutants, such as coal and dust, are the interventions most likely to succeed against COPD in Latin America. The information obtained by a collaborative study has been vast and encouraging for other similar studies.

Transmission of tropical and geographically restricted infections during solid-organ transplantation.

In recent years, the increasing number of donors from different regions of the world is providing a new challenge for the management and selection of suitable donors. This is a worldwide problem in most countries with transplantation programs, especially due to the increase in immigration and international travel. This paper elaborates recommendations regarding the selection criteria for donors from foreign countries who could potentially transmit tropical or geographically restricted infections to solid-organ transplant recipients. For this purpose, an extensive review of the medical literature focusing on viral, fungal, and parasitic infections that could be transmitted during transplantation from donors who have lived or traveled in countries where these infections are endemic has been performed, with special emphasis on tropical and imported infections. The review also includes cases described in the literature as well as risks of transmission during transplantation, microbiological tests available, and recommendations for each infection. A table listing different infectious agents with their geographic distributions and specific recommendations is included.

Validation and comparison of reference equations for the 6-min walk distance test.

Exercise impairment as measured by the 6-min walk distance (6MWD) test afflicts many patients with chronic obstructive pulmonary disease (COPD) and is known to predict mortality. Reference equations for the 6MWD in adults have been published but not yet validated. The present authors prospectively followed 1,379 COPD patients for 55+/-30 months and tested the predictive value of the baseline 6MWD in metres, the 6MWD work (kg.m(-1)) and as a percentage of predicted values the 6MWD in meters according to two reference equations. All-cause mortality was the validating outcome. The best threshold values were identified for each of the tests using receiver operating characteristic (ROC) curves. The threshold values obtained were: 350 m for the 6MWD, 25,000 kg.m(-1) for the 6MWD work, and 67 and 54% predicted for the two reference equations. All modalities of the testing were similar at predicting COPD mortality and correlated well with the 6MWD test. In conclusion, all modalities of testing predict mortality in chronic obstructive pulmonary disease equally well. In the 6-min walk distance test, a value <350 m is associated with increased mortality and should be regarded as abnormal.

Population structure of the banana weevil, an introduced pest in the Canary Islands, studied by RAPD analysis.

The banana weevil (BW), Cosmopolites sordidus (Coleoptera: Curculionidae), is one of the most important insect pests of bananas and plantains. The mobility and the origin of BW infestations at the Canary Islands (Tenerife, La Gomera and La Palma) have been analysed using Random Amplified Polymorphic DNA (RAPD) as molecular markers. Populations from Costa Rica, Colombia, Uganda and Madeira were also included for comparison. One hundred and fifteen reproducible bands from eight primers were obtained. The level of polymorphism in the populations from the Canary Islands (40-62%) was in the range of those found in other populations. Nei's genetic distances, pair-wise fixation index (FST) values indicate that the closest populations are Tenerife populations among themselves (Nei's genetic distance=0.054-0.100; FST=0.091-0.157) and Costa Rica and Colombia populations (Nei's genetic distance=0.049; FST=0.113). Our results indicate the existence of BW local biotypes with limited gene flow and affected by genetic drift. These results are compatible with a unique event of colonization at Tenerife; whereas, the outbreaks in La Gomera and La Palma may come from independent introductions. The Madeira population is phylogenetically and geographically closer to the Canary Islands populations, suggesting that it is the most likely source of the insects introduced in the Canary Islands.

Tuberculosis and airflow obstruction: evidence from the PLATINO study in Latin America.

The aim of the present study was to evaluate the association between history of tuberculosis and airflow obstruction. A population-based, multicentre study was carried out and included 5,571 subjects aged > or =40 yrs living in one of five Latin American metropolitan areas: Sao Paulo (Brazil); Montevideo (Uruguay); Mexico City (Mexico); Santiago (Chile); and Caracas (Venezuela). Subjects performed pre- and post-bronchodilator spirometry and were asked whether they had ever been diagnosed with tuberculosis by a physician. The overall prevalence of airflow obstruction (forced expiratory volume in one second/forced vital capacity post-bronchodilator <0.7) was 30.7% among those with a history of tuberculosis, compared with 13.9% among those without a history. Males with a medical history of tuberculosis were 4.1 times more likely to present airflow obstruction than those without such a diagnosis. This remained unchanged after adjustment for confounding by age, sex, schooling, ethnicity, smoking, exposure to dust and smoke, respiratory morbidity in childhood and current morbidity. Among females, the unadjusted and adjusted odds ratios were 2.3 and 1.7, respectively. In conclusion, history of tuberculosis is associated with airflow obstruction in Latin American middle-aged and older adults.

Prevalence of oxygen desaturation and use of oxygen at home in adults at sea level and at moderate altitude.

The aim of this study was to determine the prevalence of oxygen desaturation in adults aged>or=40 yrs as altitude above sea level increases. A population-based, cross-sectional study with a multistage cluster sampling of 1,063 subjects from metropolitan Mexico City (Mexico; 2,240 m above sea level), 1,357 from Caracas (Venezuela; 950 m) and 943 from Montevideo (Uruguay; 35 m). The mean of six measurements of arterial oxygen saturation (SP,O2) was estimated using a pulse oximeter. Mean SP,O2 decreased with altitude. No subject from Montevideo had a mean SP,O288%. In conclusion, the prevalence of hypoxaemia was closely related to altitude. Priorities for oxygen prescription must be defined in moderate altitudes because it is unfeasible to provide it to all subjects fulfilling the criteria commonly used.

Skeletal muscle inflammation and nitric oxide in patients with COPD.

In chronic obstructive pulmonary disease (COPD) the presence of systemic inflammation has been associated with peripheral muscle abnormalities and weight loss. To study whether inflammatory factors are important in these processes, the present study compared the skeletal muscle levels of nitrite, nitrate, nitrotyrosine, neuronal, endothelial and inducible nitric oxide synthases (nNOS, eNOS, and iNOS, respectively), and inflammatory markers (tumour necrosis factor (TNF)-alpha, CD154 and CD163) in 15 patients (forced expiratory volume in one second 43+/-11%) and 14 controls. All these markers were also compared between patients with normal and low body weight. Nitrite (12.5+/-2.6 versus 17.0+/-3.4 micromol.mg(-1) protein), nitrate (20.7+/-2.4 versus 24.4+/-4.5 micromol.mg(-1) protein) and eNOS (31.9+/-4.6 versus 43.6+/-7.5 ng.mg(-1) protein) were lower in COPD patients than in controls. Nitrotyrosine (25.6+/-5.4 versus 6.6+/-3.3 ng.mg(-1) protein), iNOS expression (32+/-9.5 versus 7.16+/-2.7 ng.mg(-1) protein), TNF-alpha (257+/-160 versus 48.3+/-4.4 pg.mg(-1) protein) and CD163 (6.4+/-2.1 versus 0.8+/-0.4 ng.mg(-1) protein) were higher in COPD patients than in controls. CD154 levels were 15.7+/-7.0 ng.mg(-1) protein in COPD patients and undetectable in controls. Similar levels of all these markers were observed in COPD patients with normal and low body weight. In conclusion, these findings suggest the presence of an inflammatory process in the muscle tissue of chronic obstructive pulmonary disease patients, and argue in favour of its participation in the pathogenesis of skeletal muscle abnormalities.

[Changes in exercise tolerance, health related quality of life, and peripheral muscle characteristics of chronic obstructive pulmonary disease patients after 6 weeks' training]. / Cambios en la tolerancia al ejercicio, calidad de vida relacionada con la salud y características de los músculos periféricos después de 6 semanas de entrenamiento en pacientes con EPOC.

OBJECTIVE: This study was designed to assess changes in skeletal muscle characteristics after 6 weeks' high-intensity physical training of patients with moderate to severe chronic obstructive pulmonary disease (COPD) and to determine how the changes were related to improvements in exercise tolerance and health related quality of life (HRQL). PATIENTS AND METHODS: Ten patients with a mean (SD) age of 60 (10) years and a forced expiratory volume in 1 second of 32% (9%) were enrolled. The effect of training on the 6-minute walk test, HRQL questionnaires, and skeletal muscles was examined for the 8 patients who completed the program. The structural and chemical characteristics of skeletal muscles before and after training were studied in vastus lateralis muscle biopsies. RESULTS: Training significantly modified the 6-minute walk test (P<.01), HRQL (P<.05), and citrate synthetase activity (P<.05). Changes in distances walked during the 6-minute walk test were significantly related to changes in the mean area of fibers (r=0.81). CONCLUSIONS: The results of this study indicate that 6 weeks of high-intensity physical training of COPD patients produces moderate changes in skeletal muscles which could partly explain improvements observed in exercise tolerance after respiratory rehabilitation.

Cambios en la tolerancia del ejercicio, calidad de vida relacionada con la salud y características de los moluscos periféricos después de 6 semanas de entrenamiento en pacientes con EPOC / Changes in exercise tolerance, health related quality of life, and peripheral muscle characteristics of chronic obstructive pulmonary disease patients after 6 weeks´ training

Objetivo: Este estudio se diseñó para evaluar los cambios en las características de los músculos esqueléticos después de 6 semanas de entrenamiento físico de alta intensidad, en pacientes con enfermedad pulmonar obstructiva crónica (EPOC) moderada-grave, y para determinar cómo se relacionan con la mejoría de la tolerancia al esfuerzo y la calidad de vida relacionada con la salud (CVRS). Pacientes y métodos: Se estudió a 10 pacientes (edad media ± desviación estándar: 60 ± 10 años) con un volumen espiratorio forzado en el primer segundo del 32 ± 9%. Se analizaron el efecto del entrenamiento sobre la marcha de 6 min (M6M), cuestionarios de CVRS y músculos esqueléticos en los 8 pacientes que completaron el programa. Se estudiaron las características histoquímicas y morfológicas de los músculos esqueléticos antes y después del entrenamiento en biopsias del vastus lateralis. Resultados: La intervención de estos pacientes modificó significativamente la M6M (p < 0,01), la CVRS (p < 0,05) y la actividad de la citrato sintetasa (p < 0,05). El cambio en la distancia recorrida durante la M6M se relacionó significativamente con el cambio en el área promedio de las fibras (r = 0,81). Conclusiones: Los resultados de este trabajo indican que la intervención con 6 semanas de entrenamiento físico de alta intensidad en pacientes con EPOC induce cambios modestos en los músculos esqueléticos, que podrían explicar en parte los beneficios observados en la tolerancia al esfuerzo tras la rehabilitación respiratoria

Objective: This study was designed to assess changes in skeletal muscle characteristics after 6 weeks' high-intensity physical training of patients with moderate to severe chronic obstructive pulmonary disease (COPD) and to determine how the changes were related to improvements in exercise tolerance and health related quality of life (HRQL). Patients and methods: Ten patients with a mean (SD) age of 60 (10) years and a forced expiratory volume in 1 second of 32% (9%) were enrolled. The effect of training on the 6-minute walk test, HRQL questionnaires, and skeletal muscles was examined for the 8 patients who completed the program. The structural and chemical characteristics of skeletal muscles before and after training were studied in vastus lateralis muscle biopsies. Results: Training significantly modified the 6-minute walk test (P<.01), HRQL (P<.05), and citrate synthetase activity (P<.05). Changes in distances walked during the 6-minute walk test were significantly related to changes in the mean area of fibers (r=0.81). Conclusions: The results of this study indicate that 6 weeks of high-intensity physical training of COPD patients produces moderate changes in skeletal muscles which could partly explain improvements observed in exercise tolerance after respiratory rehabilitation