Nutritional Assessment and Delivery in Renal Replacement Therapy Patients

ISCCM Guidelines on Acute Kidney Injury and Renal Replacement Therapy

Acute kidney injury (AKI) is a complex syndrome with a high incidence and considerable morbidity in critically ill patients. Renal replacement therapy (RRT) remains the mainstay of treatment for AKI. There are at present multiple disparities in uniform definition, diagnosis, and prevention of AKI and timing of initiation, mode, optimal dose, and discontinuation of RRT that need to be addressed. The Indian Society of Critical Care Medicine (ISCCM) AKI and RRT guidelines aim to address the clinical issues pertaining to AKI and practices to be followed for RRT, which will aid the clinicians in their day-to-day management of ICU patients with AKI.

How to cite this article

Mishra RC, Sodhi K, Prakash KC, Tyagi N, Chanchalani G, Annigeri RA, et al. ISCCM Guidelines on Acute Kidney Injury and Renal Replacement Therapy. Indian J Crit Care Med 2022;26(S2):S13-S42.

Nutritional assessment and support during continuous renal replacement therapy

Malnutrition is highly prevalent in patients with acute kidney injury, especially in those receiving renal replacement therapy (RRT). For the assessment of nutritional status, a combination of screening tools, anthropometry, and laboratory parameters is recommended rather than a single test. To avoid underfeeding and overfeeding during RRT, energy expenditure should be measured by indirect calorimetry or calculated using predictive equations. Nitrogen balance should be periodically measured to assess the degree of catabolism and to evaluate protein intake. However, there is limited data for nutritional targets specifically for patients on RRT, such as protein intake. The composition of commercial solutions for continuous renal replacement therapy (CRRT) varies. CRRT itself can be associated with both, nutrient losses into the effluent fluid and caloric gain from dextrose, lactate, and citrate. The role of micronutrient supplementation, and potential use of micronutrient enriched CRRT solutions in this setting is unknown, too. This review provides an overview of existing knowledge and uncertainties related to nutritional aspects in patients on CRRT and emphasizes the need for more research in this area.

Protein-Energy Wasting Assessment and Clinical Outcomes in Patients with Acute Kidney Injury: A Systematic Review with Meta-Analysis

Nutritional assessment is essential to identify patients with acute kidney injury (AKI) who are protein-energy wasting (PEW) and at risk of poor clinical outcomes. This systematic review aimed to investigate the relationship of nutritional assessments for PEW with clinical outcomes in patients with AKI. A systematic search was performed in PubMed, Scopus, and Cochrane Library databases using search terms related to PEW, nutrition assessment, and AKI to identify prospective cohort studies that involved AKI adult patients with at least one nutritional assessment performed and reported relevant clinical outcomes, such as mortality, length of stay, and renal outcomes associated with the nutritional parameters. Seventeen studies reporting eight nutritional parameters for PEW assessment were identified and mortality was the main clinical outcome reported. A meta-analysis showed that PEW assessed using subjective global assessment (SGA) was associated with greater mortality risk (RR: 1.99, 95% CI: 1.36–2.91). Individual nutrition parameters, such as serum chemistry, body mass, muscle mass, and dietary intakes, were not consistently associated with mortality. In conclusion, SGA is a valid tool for PEW assessment in patients with AKI, while other nutrition parameters in isolation had limited validity for PEW assessment.

Nutrition Support in Critically Ill Patients with AKI

How to cite this article: Ramakrishnan N, Shankar B. Nutrition Support in Critically Ill Patients with AKI. Indian J Crit Care Med 2020;24(Suppl 3):S135-S139.

[Metabolic management and nutrition in critically ill patients with renal dysfunction : Recommendations from the renal section of the DGIIN, ÖGIAIN, and DIVI]

BACKGROUND

Intensive care patients with renal failure or insufficiency comprise a heterogeneous group of subjects with widely differing metabolic patterns and nutritional requirements. They include subjects with various stages of acute kidney injury (AKI), acute-on-chronic renal failure (A-CKD), without/with renal replacement therapy (RRT), chronic kidney disease (CKD), and subjects on regular hemodialysis or peritoneal dialysis therapy (HD/PD).

GOALS

Development of recommendations by the renal section of DGIIN (Deutsche Gesellschaft für Internistische Intensivmedizin und Notfallmedizin), ÖGIAIN (Österreichische Gesellschaft für Internistische und Allgemeine Intensivmedizin und Notfallmedizin) and DIVI (Deutsche Interdisziplinäre Vereinigung für Intensiv- und Notfallmedizin) for the metabolic management and the planning, indication, implementation, and monitoring of nutrition therapy in this heterogeneous group of patients.

MATERIALS AND METHODS

The recommendations are based on recent evidence and current recommendations of DGEM (Deutsche Gesellschaft für Ernährungsmedizin), ASPEN (American Society for Parenteral and Enteral Nutrition) and ESPEN (European Society for Clinical Nutrition and Metabolism) and also the KDGIO (Kidney Disease: Improving Global Outcomes) clinical practice guidelines for AKI and the expert knowledge and clinical experience of the authors.

RESULTS

Nutrition support in these patient groups is not fundamentally different from that in other disease states but must consider the multiple variations in metabolism and nutrient requirements. Nutrition therapy must be adapted to the stage of disease and especially, in those patients on RRT. Nutritional needs can differ widely between patients but also in the same patient during the course of the disease.

CONCLUSIONS

Thus, the patient with renal failure requires an individualized approach in nutrition support and because of the altered metabolism of many nutrients and intolerances for electrolytes and fluids, the nutrition support in patients with renal insufficiency requires close clinical and laboratory monitoring.

Practice Guidelines for Nutrition in Critically Ill Patients: A Relook for Indian Scenario

Background and Aim:

Intensive-care practices and settings may differ for India in comparison to other countries. While international guidelines are available to direct the use of enteral nutrition (EN), there are no recommendations specific to Indian settings. Advisory board meetings were arranged to develop the practice guidelines specific to Indian context, for the use of EN in critically ill patients and to overcome challenges in this field.

Methods:

Various existing guidelines, meta-analyses, randomized controlled trials, controlled trials, and review articles were reviewed for their contextual relevance and strength. A systematic grading of practice guidelines by advisory board was done based on strength of the supporting evidence. Wherever Indian studies were not available, references were taken from the international guidelines.

Results:

Based on the literature review, the recommendations for developing the practice guidelines were made as per the grading criteria agreed upon by the advisory board. The recommendations were to address challenges regarding EN versus parenteral nutrition; nutrition screening and assessment; nutrition in hemodynamically unstable; route of nutrition; tube feeding and challenges; tolerance; optimum calorie-protein requirements; selection of appropriate enteral feeding formula; micronutrients and immune-nutrients; standard nutrition in hepatic, renal, and respiratory diseases and documentation of nutrition practices.

Conclusion:

This paper summarizes the optimum nutrition practices for critically ill patients. The possible solutions to overcome the challenges in this field are presented as practice guidelines at the end of each section. These guidelines are expected to provide guidance in critical care settings regarding appropriate critical-care nutrition practices and to set up Intensive Care Unit nutrition protocols.

Prevention and Therapy of Acute Kidney Injury in the Developing World

Timely recognition of patients at risk or with possible acute kidney injury (AKI) is essential for early intervention to minimize further damage and improve outcome. Initial management of patients with suspected and persistent AKI should include thorough clinical assessment of all patients with AKI to identify reversible factors, including fluid volume status, potential nephrotoxins, and an assessment of the underlying health of the kidney. Based on these assessments, early interventions to provide appropriate and adequate fluid resuscitation while avoiding fluid overload, removal of nephrotoxins, and adjustment of drug doses according to the level of kidney function derangement are important. The judicious use of diuretics for fluid overload and/or in cardiac decompensated patients and introduction of early enteral nutritional support need to be considered to improve outcomes in AKI. Although these basic principles are well recognized, their application in clinical practice in low resource settings is often limited due to lack of education, availability of resources, and lack of trained personnel, which limits access to care. We report the consensus recommendations of the 18th Acute Dialysis Quality Initiative meeting in Hyderabad, India, on strategies to evaluate patients with suspected AKI and initiate measures for prevention and management to improve outcomes, particularly in low resource settings. These recomendations provide a framework for caregivers, who are often primary care physicians, nurses, and other allied healthcare personnel, to manage patients with AKI in resource poor countries.

Acute kidney injury in the perioperative period and in intensive care units (excluding renal replacement therapies)

Acute kidney injury (AKI) is a syndrome that has progressed a great deal over the last 20 years. The decrease in urine output and the increase in classical renal biomarkers, such as blood urea nitrogen and serum creatinine, have largely been used as surrogate markers for decreased glomerular filtration rate (GFR), which defines AKI. However, using such markers of GFR as criteria for diagnosing AKI has several limits including the difficult diagnosis of non-organic AKI, also called "functional renal insufficiency" or "pre-renal insufficiency". This situation is characterized by an oliguria and an increase in creatininemia as a consequence of a reduction in renal blood flow related to systemic haemodynamic abnormalities. In this situation, "renal insufficiency" seems rather inappropriate as kidney function is not impaired. On the contrary, the kidney delivers an appropriate response aiming to recover optimal systemic physiological haemodynamic conditions. Considering the kidney as insufficient is erroneous because this suggests that it does not work correctly, whereas the opposite is occurring, because the kidney is healthy even in a threatening situation. With current definitions of AKI, normalization of volaemia is needed before defining AKI in order to avoid this pitfall.

Protein Feeding in Pediatric Acute Kidney Injury Is Not Associated With a Delay in Renal Recovery

OBJECTIVE

Critically ill children with acute kidney injury (AKI) are at high risk of underfeeding. Newer guidelines for nutrition support recommend higher protein intake. Therefore, the study evaluated the effects of protein feeding on the resolution of AKI and compared energy and protein intake in patients with and without AKI after implementation of Nutrition Support guidelines.

DESIGN

Retrospective study.

SUBJECTS

Five hundred twenty critically ill children from October 2012 to June 2013 and October to December 2013.

MAIN OUTCOME MEASURE

Energy and protein intake in patients with no AKI, resolved, or persistent AKI. Energy and protein intake was documented for days 1-8 of Pediatric Intensive Care Unit stay and in the postimplementation versus preimplementation period of nutrition support guidelines. AKI was defined by modified pRIFLE. Persistent AKI was defined as patients who did not resolve their AKI during the study period.

RESULTS

A higher percentage of patients with resolved and persistent AKI met ≥ 80% of protein needs versus no AKI. After adjustment for Pediatric Risk of Mortality Score, the odds ratio for protein intake of ≥ 80% compared to <80% of estimated protein needs was not significant, which suggests that higher protein intake was not associated with nonresolution of AKI. There were significant improvements in the cumulative protein gap in patients with no AKI in the postimplementation (-1.0 [-1.7 to -0.6] g/kg/day) compared to preimplementation period (-1.3 [-1.7 to -0.9] g/kg/day, P = .001) and persistent AKI in the postimplementation (-0.8 [-1.4 to -0.1] g/kg/day) compared to preimplementation (-1.3 [-1.7 to -0.9] g/kg/day, P = .03).

CONCLUSIONS

Higher protein intake was not associated with a delay in renal recovery in patients with AKI after adjustment for severity of illness. Protein intake was improved in critically ill children with no AKI, resolved, and persistent AKI after implementation of Nutrition Support Guidelines, but underfeeding persisted in these patients.

Estimating Catabolism: A Possible Tool for Nutritional Monitoring of Patients With Acute Kidney Injury

Hypercatabolism has been described as the main nutritional change in acute kidney injury. Catabolism may be defined as the excessive release of amino acids from skeletal muscle. Conditions such as fasting, inadequate nutritional support, renal replacement therapy, metabolic acidosis, and secretion of catabolic hormones are the main factors that affect protein catabolism. Given the imprecision of the methods conventionally used to assess and monitor the nutritional status of hospitalized patients, the parameters of protein catabolism, such as nitrogen balance, urea nitrogen appearance, and protein catabolic rate appear to be the main measures in this population. Considering the high prevalence of malnutrition in this population and important limitations in this clinical condition, such as the inflammatory state and altered fluid, catabolism parameters are accurate and reliable methods that could contribute to minimize adverse prognosis in this population.

Metabolic implications of peritoneal dialysis in patients with acute kidney injury

BACKGROUND

Peritoneal dialysis (PD) is a treatment for selected acute kidney injury patients (AKI), but little is known about its metabolic implications. The aim of the present study was to evaluate the metabolic implications of glucose absorption, sodium removal, protein loss into the dialysate, and catabolism in AKI patients undergoing high-volume PD and to identify risk factors associated with those metabolic effects.

METHODS

A prospective cohort study over 18 consecutive months evaluated 208 sessions of high-volume PD performed in 31 AKI patients. One session of high-volume PD lasted 24 hours. Repeated-measures analysis was performed, and correlations were calculated using the Spearman test for continuous variables and generalized linear models for categorical variables.

RESULTS

Glucose absorption remained at approximately 35.3% ± 10.5% per session. Protein loss measured 4.2 ± 6.1 g daily, with higher values initially, which declined significantly after 2 sessions. Nitrogen balance (NB) was initially negative, but stabilized at approximately zero after 3 sessions. Glucose uptake was positively correlated with the Acute Tubular Necrosis Individual Severity Score [ATNISS (r = 0.21, p = 0.0036)], C-reactive protein (r = 0.26, p = 0.0167), protein loss (r = 0.36, p < 0.0001), and sodium removal (r = 0.24, p = 0.002). Protein loss was positively correlated with sodium removal (r = 0.22, p = 0.0085) and gastrointestinal disease (p = 0.0004). Sodium removal was positively correlated with serum sodium (r = 0.21, p = 0.0064), ATNISS (r = 0.15, p = 0.0411), urea nitrogen appearance [UNA (r = 0.24, p = 0.0019)], and fluid overload as an indication for dialysis (p < 0.0001). Urea nitrogen appearance was positively correlated with the indication for dialysis (electrolyte disturbances: p = 0.0287) and negatively correlated with nephrotoxic AKI (p < 0.0001). Nitrogen balance was negatively correlated with UNA (r = -0.389, p < 0.0001) and ischemic AKI (p = 0.0047).

CONCLUSIONS

High-volume PD did not increase hypercatabolism in AKI patients, and protein loss and glucose uptake remained constant during treatment. Those parameters were influenced by the clinical condition of the patients, including the cause of AKI, inflammation, and comorbidities-factors that should be known before the prescription of dialysis and nutrition, thus avoiding metabolic complications such as hyperglycemia, hypernatremia, and worsening catabolism.

Peritoneal dialysis in an extremely low-birth-weight infant with acute kidney injury

Critically ill neonates are at high risk for acute kidney injury (AKI). Renal supportive therapy (RST) can be an important tool for supporting critically ill neonates with AKI, particularly in cases of oliguria and fluid overload. There are few reports of RST for management of oligo-anuric AKI in the extremely low-birth-weight infant weighing <1000 g. We report successful provision of peritoneal dialysis (PD) to an 830-g neonate with oligo-anuric AKI through adaptation of a standard pediatric acute PD catheter.

Nutritional parameters are associated with mortality in acute kidney injury

OBJECTIVE

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.

METHOD

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.

RESULTS

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).

CONCLUSIONS

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.

Protein/energy debt in critically ill children in the pediatric intensive care unit: acute kidney injury as a major risk factor

Acute kidney injury (AKI) is common in pediatric intensive care unit (PICU) patients. In this clinical setting, the risk of protein-energy wasting is high because of the metabolic derangements of the uremic syndrome, the difficulties in nutrient needs estimation, and the possible negative effects of renal replacement therapy itself on nutrient balance. No specific guidelines on nutritional support in PICU patients with AKI are currently available. The present review is aimed at evaluating the role of AKI as a risk condition for inadequate protein/energy intake in these patients, on the basis of literature data on quantitative aspects of nutritional support in PICU. Current evidence suggests that a relevant protein/energy debt, a widely accepted concept in the literature on adult intensive care unit patients with its negative implications for patients' major outcomes, is also likely to develop in pediatric critically ill patients, and that AKI represents a key factor for its development.

In vitro glucose kinetics during continuous renal replacement therapy: implications for caloric balance in critically ill patients

PURPOSE

To examine the impact of continuous renal replacement therapy (CRRT) on glucose kinetics and therefore caloric balance.

METHODS

In vitro experiments were conducted to characterize glucose kinetics in a variety of CRRT modalities and prescriptions. Additional experiments evaluated the impact of citrate anticoagulation using anti-coagulant dextrose solution A (ACD-A) on CRRT glucose movement. A formula was developed to predict the glucose delivery to/from the patient per day of CRRT, and this data was extrapolated to determine the net caloric impact of CRRT.


RESULTS

A total of 104 experiments were conducted with an overall glucose extraction coefficient of 1.04 (95% CI 1.03-1.05). CRRT-related glucose removal was directly related to effluent (dialysate and/or hemofiltration) rate and pre-filter blood glucose concentration, and inversely related to dialysis solution glucose concentration. In all modalities tested, CRRT resulted in a net negative glucose balance, with estimated caloric losses ranging between 20 kcal and 550 kcal depending on the conditions tested. The addition of ACD-A resulted in net glucose delivery in some conditions and a positive caloric balance of up to 470 kcal per day.

CONCLUSIONS

CRRT can have a significant effect on glucose balance and result in either significant daily caloric gains or losses, and this effect can be predicted based on CRRT prescription and patient characteristics. Clinicians should be aware of this potential impact when prescribing nutritional therapy to patients undergoing CRRT, as an imbalance in caloric feeding can adversely affect outcomes in critically ill patients.

[Nutrition and renal insufficiency]

Renal failure patients in the intensive care unit comprise a heterogeneous group of subjects with widely differing metabolic patterns and nutritional requirements. This group includes patients with acute kidney injury (AKI), acute-on-chronic renal failure, chronic kidney disease, and those on regular hemodialysis therapy. Renal failure is associated with a broad spectrum of specific metabolic alterations. In addition to these alterations and the often underrated impact of renal replacement therapy, the metabolism is also affected by the underlying disease process as well as associated organ failures and complications, especially infections. Nutritional support for renal failure is not fundamentally different from other disease processes, but in designing a nutrition regimen the variations in metabolism and nutrient requirements should be considered. Nutritional needs can differ widely between patients but also in the same patient during the course of disease. Thus, patients with renal failure require an individualized approach to nutritional support. Moreover, because of the altered metabolism of many nutrients and the intolerance of fluids and electrolytes, close monitoring of the nutritional therapy is mandatory in patients with renal failure.

Nutritional evaluation and management of AKI patients

Protein-energy wasting is common in patients with acute kidney injury (AKI) and represents a major negative prognostic factor. Nutritional support as parenteral and/or enteral nutrition is frequently needed because the early phases of this are often a highly catabolic state, although the optimal nutritional requirements and nutrient intake composition remain a partially unresolved issue. Nutrient needs of patients with AKI are highly heterogeneous, depending on different pathogenetic mechanisms, catabolic rate, acute and chronic comorbidities, and renal replacement therapy (RRT) modalities. Thus, quantitative and qualitative aspects of nutrient intake should be frequently evaluated in this clinical setting to achieve better individualization of nutritional support, to integrate nutritional support with RRT, and to avoid under- and overfeeding. Moreover, AKI is now considered a kidney-centered inflammatory syndrome; indeed, recent experimental data indicate that specific nutrients with anti-inflammatory effects could play an important role in the prevention of renal function loss after an episode of AKI.

Specialized nutritional support interventions in critically ill patients on renal replacement therapy

PURPOSE OF REVIEW

Optimal nutritional requirements and nutrient intake composition for patients with acute kidney injury remain a partially unresolved issue. Targeting nutritional support to the actual protein and energy needs improves the clinical outcome of critically ill patients, yet very few data are currently available on this topic in acute kidney injury. In this specific clinical condition the risk for underfeeding and overfeeding may be increased by factors interfering on nutrient need estimation, such as rapidly changing body weight due to fluid balance variations, nutrient losses and hidden calorie sources from renal replacement therapy. Moreover, as acute kidney injury is now considered a kidney-centered inflammatory syndrome, the renoprotective role of specific pharmaconutrients with anti-inflammatory properties remains to be fully defined. This review is aimed at discussing recently published results concerning quantitative and qualitative aspects of the nutritional approach to acute kidney injury in critically ill patients.

RECENT FINDINGS

Nutrient needs in patients with acute kidney injury can be difficult to estimate, and should be directly measured, especially in the ICU setting. In fact, recent findings suggest that hidden calorie sources not routinely taken into account - for example, calories from anticoagulants and replacement solutions for renal replacement therapy - could be quantitatively relevant in these patients. Moreover, recent experimental data indicate a possible role for some pharmaconutrients with anti-inflammatory effects (glutamine, and omega-3 fatty acids), in both the prevention of renal function worsening, and in the fostering of renal function recovery after an episode of acute kidney injury.

SUMMARY

Acute kidney injury includes a highly heterogeneous group of patients with widely varying nutrient needs and intakes. Nutritional requirements, in their quantitative and qualitative aspects, should be frequently assessed, individualized, and carefully integrated with renal replacement therapy, in order to avoid both underfeeding and overfeeding, as well as to exploit possible positive pharmacologic effects of specific nutrients.

Nutrition support among critically ill children with AKI

BACKGROUND

Critically ill children are at high risk of underfeeding and AKI, which may lead to further nutritional deficiencies. This study aimed to determine the adequacy of nutrition support during the first 5 days of intensive care unit (ICU) stay.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A chart review of pediatric patients admitted to the pediatric ICU for >72 hours between August 2007 and March 2008 was conducted. Patients were classified as having no AKI versus AKI by modified pediatric RIFLE criteria. All nutrition was analyzed. Basal metabolic rate (BMR) was estimated by the Schofield equation and protein needs by American Society for Parenteral and Enteral Nutrition guidelines.

RESULTS

Of the 167 patients, 102 were male and 65 were female (median age 1.4 years). Using the RIFLE criteria, 102 (61%) patients had no AKI, whereas 44 (26%) were classified as category R (risk), 12 (7%) as category I (injury), and 9 (5%) as category F (failure). The median 5-day energy intake was lower relative to estimated BMR. Overall protein provision (19%) was lower than energy provision (55%) compared with estimated needs (P<0.001). I/F patients were more likely to be fasted versus receiving enteral/parenteral nutrition (n=813 patient days) and to receive <90% of BMR (n=832 patient days) than No AKI/R patients.

CONCLUSIONS

Underfeeding, common in critically ill children, was accentuated in AKI. Protein underfeeding was greater than energy underfeeding in the first 5 days of PICU stay. Efforts should be made to provide adequate nutrition in ICU patients with AKI.

Nutritional aspects in acute kidney injury

Nutritional assessment is an indispensable tool for the evaluation and clinical monitoring of patients with acute kidney injury (AKI). Acute loss of renal function interferes with the metabolism of all macronutrients, responsible for proinflammatory, pro-oxidative and hypercatabolic situations. The major nutritional disorders in AKI patients are hypercatabolism, hyperglycemia, and hypertriglyceridemia. Those added to the contributions of the underlying disease, complications, and the need for renal replacement therapy can interfere in the nutritional depletion of those patients. Malnutrition in AKI patients is associated with increased incidence of complications, longer hospitalization, and higher hospital mortality. However, there are few studies evaluating the nutritional status of AKI patients. Anthropometric parameters, such as body mass index, arm circumference, and thickness of skin folds, are difficult to interpret due to changes in hydration status in those patients. Biochemical parameters commonly used in clinical practice are also influenced by non-nutritional factors like loss of liver function and inflammatory status. Although there are no prospective data about the behavior of nutritional markers, some authors demonstrated associations of some parameters with clinical outcomes. The use of markers like albumin, cholesterol, prealbumin, IGF-1, subjective global assessment, and calculation of the nitrogen balance seem to be useful as screening parameters for worse prognosis and higher mortality in AKI patients. In patients with AKI on renal replacement therapy, a caloric intake of 25 to 30 kcal/kg and a minimum amount of 1.5 g/kg/day of protein is recommended to minimize protein catabolism and prevent metabolic complications.