The effect of intermittent or continuous feeding and amino acid concentration on urea-to-creatinine ratio in critical illness.

Abstract

BACKGROUND: We sought to determine whether peaks in essential amino acid concentration associated with intermittent feeding may provide anabolic advantages when compared to continuous feeding regimens in critical care. MATERIALS AND METHODS: We performed a secondary analysis of data from a multicentre trial of UK intensive care patients randomised to intermittent or continuous feeding. A linear-mixed-effects model was developed to assess differences in urea-creatinine-ratio (raised values of which can be a marker of muscle wasting) between arms. To investigate metabolic phenotypes, we performed k-means urea-to-creatinine ratio trajectory-clustering. Amino acid concentrations were also modelled against urea-to-creatinine ratio from day 1 to day 7. The main outcome measure was serum urea-to-creatinine ratio (mmol/mmol) from day 0 to the end of the 10-day study period. RESULTS: Urea-to-creatinine ratio trajectory differed between feeding regimens (coefficient -0.245, p = 0.002). Patients receiving intermittent feeding demonstrated a flatter urea-to-creatinine ratio trajectory. With K-means analysis, the cluster with the largest proportion of continuously fed patients demonstrated the steepest rise in urea-to-creatinine ratio. Neither protein intake per se nor serum concentrations of essential amino acid concentrations were correlated with urea-to-creatinine ratio (coefficient = 0.088, p = 0.506; and coefficient <0.001, p = 0.122, respectively). CONCLUSION: Intermittent feeding can mitigate the rise in urea-to-creatinine ratio otherwise seen in those continuously fed, suggesting that catabolism may have been to some degree prevented. This article is protected by copyright. All rights reserved.