Protein malnutrition in elderly patients with chronic obstructive pulmonary disease

Background: It has been suggested that hypermetabolism or reduction of total caloric intake or a combination of both conditions occur in malnourished patients with chronic obstructive pulmonary disease (COPD). It is hypothesized that protein malnutrition plays a role in the metabolism of malnourished elderly COPD patients.
Methods: Thirteen COPD patients (mean age: 75.7 years) with severe obstructive ventilatory disorder were divided into two groups: body mass index greater than 20 (group N; n  = 8) and less than 20 (group L; n  = 5). A nutritional survey and metabolic study were performed.
Results: Energy balances appeared more highly positive in group L than in group N and serum concentrations of total protein, albumin and transferrin tended to be lower in group L than in group N (all showed no statistically significant difference). The mean protein digestibility did not show any significant difference between the two groups, suggesting that group L subjects digested and absorbed the ingested dietary protein normally. Mean nitrogen balance was more highly positive in group L than in group N. The FEV₁ decreased significantly with increases in the basal metabolic rate (BMR), total daily energy expenditure and urinary nitrogen excretion, respectively (all P  < 0.05). PaO₂ was positively and significantly correlated with serum concentrations of albumin and transferrin ( P  = 0.001 and P  < 0.05), respectively. Body mass index (BMI) was negatively correlated with BMR ( P  < 0.05).
Conclusions: It is suggested that malnourished COPD patients with lower BMI showed enhanced protein and energy metabolism. Thus, it is likely that malnourished elderly COPD patients could improve through not only supplementation of total carolic intake but also sufficient protein intake.