[COPD disease and malnutrition]

Weight loss and malnutrition related mainly to lean mass loss can develop in advanced stages of chronic obstructive pulmonary disease (COPD) and are a clear indication of phenotypic heterogeneity. The presence of weight loss and malnutrition is associated with a worse prognosis, independently of forced expiratory volume in 1 second (FEV(1)). The most widely accepted thresholds for risk are 21 for the body mass index (BMI) and 17 and 14 for men and women, respectively, for the fat-free mass index (FFMI). The coexistence of both defines a situation of greater nutritional risk (cachexia). Nevertheless, a reduction in FFMI is an independent risk factor, although not superior to a low BMI. Therefore, although obtaining FFMI by bioelectric impedanciometry is reliable and relatively easy, we recommend the use of this procedure only in patients with COPD and low weight (BMI < 21), together with more specific nutritional evaluation. Currently, longitudinal studies providing data on the behavior of BMI within the natural course of the disease are lacking. Moreover, there is no solid scientific evidence that confirms the main mechanisms of malnutrition in COPD. This lack of evidence explains the difficulty of the therapeutic management of these patients, which has not advanced in the last few decades. Nevertheless, current evidence suggests that initiating individually-tailored nutritional treatment combined with pulmonary rehabilitation programs (exercise) is reasonable in patients with cachexia. Further studies are required to provide greater insight into the physiopathology and the role of other therapeutic options (hormones, antiinflammatory drugs) in malnutrition in patients with COPD.