Role of visceral proteins in detecting malnutrition in the elderly

Objective: In the clinical practice, visceral proteins are used as indirect markers of protein energy malnutrition (PEM), but their reliability could be reduced with advancing age. The aim of this work is to investigate the reliability of albumin, prealbumin, retinol-binding protein (RBP) and transferrin in evaluating nutritional status in old patients and their relationship with fat-free mass (FFM). Design: Cross-sectional study. Setting: Padua, Italy. Subjects: In 44 underweight (body mass index <20 kg/m(2)) (66-97 years) and 69 normal weight or overweight elderly subjects (62-98 years), albumin, prealbumin, transferrin and RBP were determined in the plasma. Body composition and particularly FFM was obtained by dual X-ray absorptiometry. FFM was also expressed as FFM index (FFMI) calculated as FFM divided by height squared. Subjects affected by acute illnesses and inflammatory states were excluded. Results: Albumin, prealbumin and RBP mean values were significantly lower in underweight subjects. No differences between two groups were found for transferrin. Albumin prealbumin and RBP resulted under the normal range in 55, 25 and 54% of underweight subjects, respectively. Transferrin's values were low in about 40% of underweight and normal weight subjects, respectively. In all subjects, FFMI shows a significant correlation with albumin (r: 0.52), prealbumin (r: 0.64) and RBP (r: 0.57). No correlation between FFMI and transferrin was found. Conclusions: Visceral proteins, except for transferrin, seem to be useful indexes in detecting malnutrition in the elderly; low values still in the normal range should also be carefully evaluated because they could suggest a poor nutritional status.