[Risk factors for mortality in chronic obstructive pulmonary disease]. / Factores de riesgo de mortalidad en la EPOC.

OBJECTIVE: Although the factors predictive of survival in patients with chronic obstructive pulmonary disease (COPD) have been widely studied, full consensus has yet to be reached. The objective of this study was to further clarify how lung function parameters, exercise tolerance, and quality of life influence survival in patients with COPD. PATIENTS AND METHODS: This prospective study included 60 patients diagnosed with COPD. At the start of the study, patients underwent respiratory function tests, exercise testing, and 6-minute walk test. They also answered a chronic respiratory disease questionnaire to measure health-related quality of life. Follow-up lasted 7 years. RESULTS: Five of the 60 patients withdrew from the study. Twenty-six of the remaining 55 patients (47%) died during the study. Univariate Cox regression analysis showed a correlation between survival and age, degree of obstruction, inspiratory capacity, carbon monoxide diffusing capacity, and peak exercise tolerance. No correlation was found between survival and body mass index, PaO2, PaCO2, total lung capacity, residual volume, maximal respiratory pressures, 6-minute walk distance, or health-related quality of life. Age, degree of obstruction (measured as the ratio of forced expiratory volume in 1 second to forced vital capacity after administration of bronchodilator), and maximum minute ventilation in the exercise test were introduced initially in the multivariate Cox stepwise regression analysis, but only maximum minute ventilation remained in the final model (relative risk, 0.926; P< .001). CONCLUSIONS: Our findings show that peak exercise tolerance is the best predictor of survival in patients with COPD.

Inspiratory muscle training in patients with chronic obstructive pulmonary disease: structural adaptation and physiologic outcomes.

The present study was aimed at evaluating the effects of a specific inspiratory muscle training protocol on the structure of inspiratory muscles in patients with chronic obstructive pulmonary disease. Fourteen patients (males, FEV1, 24 +/- 7% predicted) were randomized to either inspiratory muscle or sham training groups. Supervised breathing using a threshold inspiratory device was performed 30 minutes per day, five times a week, for 5 consecutive weeks. The inspiratory training group was subjected to inspiratory loading equivalent to 40 to 50% of their maximal inspiratory pressure. Biopsies from external intercostal muscles and vastus lateralis (control muscle) were taken before and after the training period. Muscle samples were processed for morphometric analyses using monoclonal antibodies against myosin heavy chain isoforms I and II. Increases in both the strength and endurance of the inspiratory muscles were observed in the inspiratory training group. This improvement was associated with increases in the proportion of type I fibers (by approximately 38%, p < 0.05) and in the size of type II fibers (by approximately 21%, p < 0.05) in the external intercostal muscles. No changes were observed in the control muscle. The study demonstrates that inspiratory training induces a specific functional improvement of the inspiratory muscles and adaptive changes in the structure of external intercostal muscles.

Factores de riesgo de mortalidad en la EPOC / Risk factors for mortality in Chronic Obstructive Pulmonary Disease

Objetivo: Aunque los factores que predicen la supervivencia en pacientes con enfermedad pulmonar obstructiva crónica (EPOC) han sido ampliamente estudiados, no disponemos de un consenso establecido. El objetivo de este estudio ha sido contribuir a clarificar el papel que desempeñan los parámetros de función pulmonar, tolerancia al esfuerzo y calidad de vida en la supervivencia en la EPOC. Pacientes y métodos: Se diseñó un estudio prospectivo en el que se incluyó a 60 pacientes diagnosticados de EPOC. Al inicio del estudio realizaron pruebas funcionales respiratorias, prueba de esfuerzo máximo y prueba de la marcha de 6 min, y respondieron un cuestionario de enfermedad respiratoria crónica para determinar la calidad de vida relacionada con la salud. El seguimiento de los pacientes fue de 7 años. Resultados: Se retiraron del estudio 5 de los 60 pacientes. De los 55 restantes, 26 (47%) murieron durante el estudio. El análisis univariante con regresión de Cox mostró que existía relación entre la supervivencia y la edad, el grado de obstrucción, la capacidad inspiratoria, la capacidad de difusión del monóxido de carbono y la tolerancia al ejercicio máximo; no se observó dicha relación entre la supervivencia y el índice de masa corporal, la presión arterial de oxígeno y anhídrido carbónico, la capacidad pulmonar total, el volumen residual, las presiones máximas respiratorias, la prueba de la marcha de 6 min ni la calidad de vida relacionada con la salud. En el análisis multivariante con regresión de Cox con pasos hacia adelante, en el que se introdujeron la edad, el grado de obstrucción (medido con la relación volumen espiratorio forzado en el primer segundo/capacidad vital forzada tras la administración de broncodilatador) y la ventilación minuto máxima en la prueba de esfuerzo, sólo esta última entró en el modelo final (riesgo relativo = 0,926; p < 0,001). Conclusiones: Nuestros hallazgos demuestran que la tolerancia al ejercicio máximo es el mejor predictor de supervivencia en los pacientes con EPOC

Objective: Although the factors predictive of survival in patients with chronic obstructive pulmonary disease (COPD) have been widely studied, full consensus has yet to be reached. The objective of this study was to further clarify how lung function parameters, exercise tolerance, and quality of life influence survival in patients with COPD. Patients and methods: This prospective study included 60 patients diagnosed with COPD. At the start of the study, patients underwent respiratory function tests, exercise testing, and 6-minute walk test. They also answered a chronic respiratory disease questionnaire to measure health-related quality of life. Follow-up lasted 7 years. Results: Five of the 60 patients withdrew from the study. Twenty-six of the remaining 55 patients (47%) died during the study. Univariate Cox regression analysis showed a correlation between survival and age, degree of obstruction, inspiratory capacity, carbon monoxide diffusing capacity, and peak exercise tolerance. No correlation was found between survival and body mass index, PaO2, PaCO2, total lung capacity, residual volume, maximal respiratory pressures, 6-minute walk distance, or health-related quality of life. Age, degree of obstruction (measured as the ratio of forced expiratory volume in 1 second to forced vital capacity after administration of bronchodilator), and maximum minute ventilation in the exercise test were introduced initially in the multivariate Cox stepwise regression analysis, but only maximum minute ventilation remained in the final model (relative risk, 0.926; P<.001). Conclusions: Our findings show that peak exercise tolerance is the best predictor of survival in patients with COPD