Prevalence of glutamine deficiency in ICU patients: a cross-sectional analytical study

Nutrition Journal, Aug 2016

Background Not only is glutamine deficiency an independent predictor of mortality in intensive care unit (ICU) patients, but glutamine supplementation is also recommended for its proven outcome benefits. However, recent data suggest that early glutamine supplementation in certain patient groups increase mortality. The aim of this study was to investigate plasma glutamine levels of adult ICU patients in the South African setting and to determine relationships between glutamine levels, gender, diagnostic categories and selected inflammatory markers. The data from this study will be used as baseline measurement to support a large scale study that will be undertaken in the South African ICU population. Methods This cross-sectional, analytical study included 60 mixed adult ICU patients within 24 h post ICU admission. Plasma glutamine levels were determined on admission. The relationship between glutamine levels, Interleukin-6 (IL-6) and C-reactive protein (CRP); as well as gender- and diagnosis-related differences in glutamine levels were also investigated. A non-parametric ROC curve was computed to determine the CRP concentration cut-off point above which glutamine becomes deficient. Results The median plasma glutamine level (497 μmol/L) was in the normal range; however, 38.3 % (n = 23) of patients had deficient (<420 μmol/L) and 6.7 % (n = 4) had supra-normal glutamine levels (>930 μmol/L). No significant difference could be detected between glutamine levels and gender or diagnosis categories as a group. When only the medical and surgical categories were compared, the median plasma glutamine level of the medical patients were significantly lower than that of the surgical patients (p = 0.042). Glutamine showed inverse associations with CRP levels (r = −0.44, p < 0.05) and IL-6 concentrations (r = −0.23, p = 0.08). A CRP cut-off value of 95.5 mg/L was determined above which glutamine levels became deficient. Conclusions About a third of patients (38 %) were glutamine deficient on admission to ICU, whereas some presented with supra-normal levels. While glutamine levels correlated inversely with inflammatory markers, and a CRP value of above 95.5 mg/L indicated potential glutamine deficiency, the clinical application of this finding needs further investigation.

A PDF file should load here. If you do not see its contents the file may be temporarily unavailable at the journal website or you do not have a PDF plug-in installed and enabled in your browser.

Alternatively, you can download the file locally and open with any standalone PDF reader:

http://www.nutritionj.com/content/pdf/s12937-016-0188-3.pdf

Prevalence of glutamine deficiency in ICU patients: a cross-sectional analytical study

Nienaber et al. Nutrition Journal Prevalence of glutamine deficiency in ICU patients: a cross-sectional analytical study Arista Nienaber 1 Robin Claire Dolman 1 Averalda Eldorine van Graan 1 Renee Blaauw 0 0 Division of Human Nutrition, Faculty of Medicine and Health Sciences, Stellenbosch University , PO Box 241, Cape Town , South Africa 1 Centre of Excellence for Nutrition, North-West University , Potchefstroom Campus, Potchefstroom , South Africa Background: Not only is glutamine deficiency an independent predictor of mortality in intensive care unit (ICU) patients, but glutamine supplementation is also recommended for its proven outcome benefits. However, recent data suggest that early glutamine supplementation in certain patient groups increase mortality. The aim of this study was to investigate plasma glutamine levels of adult ICU patients in the South African setting and to determine relationships between glutamine levels, gender, diagnostic categories and selected inflammatory markers. The data from this study will be used as baseline measurement to support a large scale study that will be undertaken in the South African ICU population. Methods: This cross-sectional, analytical study included 60 mixed adult ICU patients within 24 h post ICU admission. Plasma glutamine levels were determined on admission. The relationship between glutamine levels, Interleukin-6 (IL-6) and C-reactive protein (CRP); as well as gender- and diagnosis-related differences in glutamine levels were also investigated. A non-parametric ROC curve was computed to determine the CRP concentration cut-off point above which glutamine becomes deficient. Results: The median plasma glutamine level (497 μmol/L) was in the normal range; however, 38.3 % (n = 23) of patients had deficient (<420 μmol/L) and 6.7 % (n = 4) had supra-normal glutamine levels (>930 μmol/L). No significant difference could be detected between glutamine levels and gender or diagnosis categories as a group. When only the medical and surgical categories were compared, the median plasma glutamine level of the medical patients were significantly lower than that of the surgical patients (p = 0.042). Glutamine showed inverse associations with CRP levels (r = −0.44, p < 0.05) and IL-6 concentrations (r = −0.23, p = 0.08). A CRP cut-off value of 95.5 mg/L was determined above which glutamine levels became deficient. Conclusions: About a third of patients (38 %) were glutamine deficient on admission to ICU, whereas some presented with supra-normal levels. While glutamine levels correlated inversely with inflammatory markers, and a CRP value of above 95.5 mg/L indicated potential glutamine deficiency, the clinical application of this finding needs further investigation. Glutamine; Intensive care unit; C-reactive protein; Interleukin-6; Gender Background Pharmaconutrition refers to nutrients that are administered as pharmacological agents, forming part of the medical treatment plan. It is currently applied in various clinical settings to improve patient outcomes [ 1 ]. Glutamine, the most abundant non-essential amino acid, is the most-researched pharmaconutrient to date [ 2 ]. Previous studies showed decreased levels of plasma and muscle glutamine in selected critically ill, post-surgical, multiple trauma, burns, septic and general intensive care unit (ICU) patients [ 3–5 ], resulting in the classification of glutamine as a “conditionally essential amino acid” under certain circumstances. Glutamine deficiency and, therefore, its unavailability to perform important functions contributes to an inappropriate response to stress and injury, ultimately leading to an increased ICU and post-ICU mortality risk. Glutamine supplementation has been extensively studied for its contribution to the improvement of patient outcomes. Until recently, it has been deemed safe and effective in a variety of patient groups, including the severely ill, burns and surgical patient [ 6–9 ]. Outcome benefits such as reductions in length of hospital stay (LOHS), length of ICU stay, mortality risk and infectious complications, as well as an improvement in nitrogen balance, was previously reported, depending on the specific patient group as well as the dose and route of administration [ 6–9 ]. The Reducing Deaths due to Oxidative Stress (REDOXS) study questioned the safety and applicability of glutamine supplementation in all patient groups. In this study an increased mortality risk was found when supplementing multiple organ failure (MOF) patients with high dosages of enteral and parenteral glutamine within 24 h after ICU admission [ 10 ]. In a sub-sample of this study only 31 % of patients were glutamine deficient (<420 μmol/L) while 15 % had supra-normal levels (>930 μmol/L). Moreover, Rodas et al. [ 11 ] found that a U-shaped curve represents the association between glutamine and mortality, where both low (<420 μmol/L) and high (>930 μmol/L) levels were associated with a higher mor (...truncated)


This is a preview of a remote PDF: http://www.nutritionj.com/content/pdf/s12937-016-0188-3.pdf

Arista Nienaber, Robin Dolman, Averalda van Graan, Renee Blaauw. Prevalence of glutamine deficiency in ICU patients: a cross-sectional analytical study, Nutrition Journal, 2016, pp. 73, 15, DOI: 10.1186/s12937-016-0188-3