Background: The association between emphysema and weight loss is well known. Severe α1-antitrypsin deficiency is an important risk factor for the development of emphysema.
Study objective: To study nutritional status and muscle strength in patients with severe α1-antitrypsin deficiency and emphysema.
Methods: Fifteen α1-antitrypsin–deficient patients with emphysema (7 men) and 18 healthy control subjects (9 men) were included in the study. Total body protein (TBP) was measured by in vivo neutron activation analysis of nitrogen. Lean body mass (LBM) was estimated from measurement of total body potassium. In analogy with body mass index (BMI), TBP index and LBM index were calculated as TBP/height squared and LBM/height squared, respectively. Respiratory muscle strength was studied by maximal inspiratory pressure (Pimax) and maximal expiratory pressure (Pemax), and skeletal muscle strength by handgrip test. Plasma albumin, transthyretin, and retinol-binding protein concentrations were analyzed as biochemical markers of nutritional status.
Results: In the α1-antitrypsin–deficient individuals, lung function test results were consistent with severe chronic airway obstruction, whereas the healthy control subjects had normal lung function. No significant differences were found in age, body weight, or BMI between the groups. TBP (p < 0.05), TBP index (p < 0.001), LBM index (p < 0.05), and plasma concentration of transthyretin (p < 0.01) were significantly lower in the patients than in the control subjects. There was a significant correlation between TBP and LBM (p < 0.001), and between TBP and body weight (p < 0.001). In the male subgroup, Pimax (p < 0.05) and Pemax (p < 0.05) were significantly lower in the patients than in the control subjects. In the female subgroup, handgrip strength was significantly lower in the patients than in the control subjects (p < 0.05). Body weight was significantly correlated with handgrip test (p < 0.05) in the male patients. In the female patients, body weight was significantly correlated with Pimax (p < 0.05), LBM with Pemax (p < 0.05), and LBM with handgrip test (p < 0.01).
Conclusion: Reduced TBP and plasma transthyretin concentration in α1-antitrypsin–deficient patients with emphysema may indicate early signs of malnutrition.