Validation of clinical control in COPD as a new tool for optimizing treatment.

BACKGROUND: It has recently been proposed that the concept of clinical control in COPD may be useful for deciding treatment in COPD, but the original control criteria (OCC) were considered too restrictive. OBJECTIVE: Define and subsequently validate "modified" control criteria (MCC) of COPD. METHOD: Prospective observational study in COPD patients with a 1-year follow-up. Control was defined as the presence of low clinical impact and clinical stability. To evaluate clinical impact, the following clinical parameters were assessed: the degree of dyspnea, use of rescue medication, physical activity, and sputum color. Stability was assessed by clinical changes and exacerbations in the last 3 months. The COPD assessment test score and their changes were also evaluated as alternative control criteria. To define the MCC, adjustment for disease severity using BODEx index (MCC-B) or FEV1 (MCC-F) was evaluated, and the best cutoff point was established. Time to first combined event (emergency visit, hospitalization, or death) was analyzed to evaluate the predictive capacity of risk of the OCC, MCC-B, and MCC-F. RESULTS: We included 265 patients, 224 (83.9%) men, with a mean age (±SD) of 68±9 years and FEV1 of 58%±17%. The proportion of controlled patients was higher using clinical MCC-B or MCC-F (61.5% and 59.6%) than OCC (27.5%). Similar percentages were found using COPD assessment test scores. The time to the first combined event was significantly greater in controlled patients using MCC criteria (P<0.001, all cases). The predictive capacity of risk was similar in MCC-B (c-statistic [C]=0.639) and MCC-F (C=0.637) and higher than OCC (C=0.589). CONCLUSIONS: The new MCC identified a higher number of controlled COPD patients. These patients have a better quality of life and lower risk of poor outcomes. The concept of control and the new MCC could be a useful tool to optimize therapy.

Skeletal muscle apoptosis and weight loss in chronic obstructive pulmonary disease.

Patients with chronic obstructive pulmonary disease (COPD) often lose weight during the course of their disease. We hypothesized that this may be due to skeletal muscle apoptosis. To investigate this possibility, we obtained quadriceps femoris biopsies in 15 patients with COPD (8 with normal body mass index [BMI] and 7 with low [< 20 kg/m(2)] BMI), 8 healthy volunteers, and 6 sedentary subjects undergoing orthopedic surgery (both groups with normal BMI). Skeletal muscle apoptosis was assessed by the transferase-mediated dUTP nick end labeling (TUNEL) technique and the immunodetection of poly-(ADP-ribose)-polymerase proteolytic fragments. Exercise tolerance on a cycloergometer was also determined in patients with COPD. We found that skeletal muscle apoptosis (by both techniques) was increased in patients with COPD and low BMI as compared with the other three groups (p < 0.005). In patients with COPD, BMI was inversely related to skeletal muscle apoptosis (TUNEL, p = 0.009), and it was better correlated with exercise capacity (p = 0.006) than with the degree of airflow obstruction present (p = 0.02). Markers of skeletal muscle apoptosis were not related to any of the measured lung function variables. This study shows that skeletal muscle apoptosis (1) is increased in patients with COPD having low BMI; and (2) is associated with a lower exercise tolerance despite a similar degree of lung function impairment.