Nutritional parameters are associated with mortality in acute kidney injury

The objective of this study was to perform a nutritional assessment of acute kidney injury patients and to identify the relationship between nutritional markers and outcomes.

This was a prospective and observational study. Patients who were hospitalized at the Hospital of Botucatu School of Medicine were evaluated between January 2009 and December 2011. We evaluated a total of 133 patients with a clinical diagnosis of acute kidney injury and a clinical presentation suggestive of acute tubular necrosis. We explored the associations between clinical, laboratory and nutritional markers and in-hospital mortality. Multivariable logistic regression was used to adjust for confounding and selection bias.

Non-survivor patients were older (67 ± 14 vs. 59 ± 16 years) and exhibited a higher prevalence of sepsis (57.1 vs. 21.4%) and higher Acute Tubular Necrosis-Individual Severity Scores (0.60 ± 0.22 vs. 0.41 ± 0.21) than did survivor patients. Based on the multivariable analysis, laboratorial parameters such as blood urea nitrogen and C-reactive protein were associated with a higher risk of death (OR: 1.013, p=0.0052; OR: 1.050, p=0.01, respectively), and nutritional parameters such as low calorie intake, higher levels of edema, lower resistance based on bioelectrical impedance analysis and a more negative nitrogen balance were significantly associated with a higher risk of death (OR: 0.950, p=0.01; OR: 1.138, p=0.03; OR: 0.995, p=0.03; OR: 0.934, p=0.04, respectively).

In acute kidney injury patients, a nutritional assessment seems to identify nutritional markers that are associated with outcome. In this study, a low caloric intake, higher C-reactive protein levels, the presence of edema, a lower resistance measured during a bioelectrical impedance analysis and a lower nitrogen balance were significantly associated with risk of death in acute kidney injury patients.