Prognostic Value of Nutritional Status in Chronic Obstructive Pulmonary Disease

Abstract

The association between low body mass index (BMI) and poor prognosis in patients with chronic obstructive pulmonary disease (COPD) is a common clinical observation. We prospectively examined whether BMI is an independent predictor of mortality in subjects with COPD from the Copenhagen City Heart Study. In total, 1,218 men and 914 women, aged 21 to 89 yr, with airway obstruction defined as an FEV(1)-to-FVC ratio of less than 0.7, were included in the analyses. Spirometric values, BMI, smoking habits, and respiratory symptoms were assessed at the time of study enrollment, and mortality from COPD and from all causes during 17 yr of follow-up was analyzed with multivariate Cox regression models. After adjustment for age, ventilatory function, and smoking habits, low BMI was predictive of a poor prognosis (i.e., higher mortality), with relative risks (RRs) in underweight subjects as compared with that in subjects of normal weight of 1.64 (95% confidence interval [CI]: 1.20 to 2.23) in men and 1.42 (95% CI: 1.07 to 1.89) in women. However, the association between BMI and survival differed significantly with stage of COPD. In mild and moderate COPD there was a nonsignificant U-shaped relationship, with the lowest risk occurring in normal-weight to overweight subjects, whereas in severe COPD, mortality continued to decrease with increasing BMI (test for trend: p < 0.001). Similar results were found for COPD-related deaths, with the strongest associations found in severe COPD (RR for low versus high BMI: 7.11 [95% CI: 2.97 to 17.05]). We conclude that low BMI is an independent risk factor for mortality in subjects with COPD, and that the association is strongest in subjects with severe COPD.

Prevalence and consequences of nutritional depletion in lung transplant candidates

“…In end-stage lung diseases, lean body mass seems to be a better tool to assess nutritional depletion and monitoring this parameter in lung transplant candidates is recommended. If mortality is considered, the study confirms that nutritional status per se is of value to predict survival while awaiting LT [4,5,13,16,17]. In the postoperative course, nutritional depletion increases the risk of death, mainly in CF patients, as shown by different groups [5,6,13] but not by others [4].…”

“…m -2 [4,5,7,13]. In COPD patients, the prevalence of nutritional depletion increases with the degree of bronchial obstruction [8,10,14,16,17], the level of hypoxaemia [8,15] and the subtype of COPD, emphysema patients being more depleted [14]. Hypoxaemia per se modifies muscle mass through a sharp decline in protein synthesis so that oxygen supply can adapt to demand [18].…”

Recommendations on the use of exercise testing in clinical practice

“…Other resting indices have been found to predict the prognosis of these patients, the most important being BMI [175,176], IC/total lung capacity (TLC) ratio [177], arterial hypoxaemia during sleep [178], pulmonary artery pressure [179], mixed venous partial pressure of oxygen (PO 2 ) [180] and the degree of functional breathlessness [181].…”

Nutritional depletion and its relationship to respiratory impairment in patients with chronic respiratory failure due to COPD or restrictive thoracic diseases

“…The association between body mass index (BMI) and prognosis in patients with chronic obstructive pulmonary disease (COPD) has been recognized for many years (GrayDonald et al, 1996;Landbo et al, 1999). Consequently, BMI has been integrated in a multidimensional score for mortality risk in COPD (Celli et al, 2004).…”