Effects of oral amino acid supplementation on long-term-care-acquired infections in elderly patients

Abstract

The very high general infection rate (IRI) observed in our Geriatric Intensive Rehabilitation Center (GIRC) led us to investigate whether patient supplementation with essential amino acids (EAAs), modulators of immuno-competence, could reduce IRI. Eighty elderly patients admitted to our GIRC ( n = 40; age 79.5 ± 7.71; male/female 14/26) or placebo ( n = 40; age 82.13 ± 6.15; male/female 13/27) were allocated to an 8 g/day oral EAAs group and were surveyed for infections (>48 h from admission) over the first month of their hospital stay. The IRI was 67% for the entire population of patients, 82.5% (33/40 patients) in the placebo group and 52% (21/40 patients) in the EAA group ( p < 0.02). When patients were divided into infection group (IG) and without-infection group (WIG), independently of post randomization allocation, the WIG had higher levels of serum albumin ( p < 0.001), blood hemoglobin (Hb) concentration ( p = 0.01), dietary protein ( p = 0.008) calorie intakes ( p = 0.05) but lower serum C-reactive protein (CRP) ( p < 0.001). The factor of CRP > 0.8 mg/dl and Hb ≤ 12 in females, ≤13 in males was associated 4 times and 3.6 times risk of infection, respectively, by sex. EAAs supplementation may lower the risk of infection by 30% in the rehabilitative elderly population. CRP and blood hemoglobin levels can be considered risk markers of future infection.