Nutritional risk and malnutrition related to chronic kidney disease (CKD) are common disorders that usually appear from CKD stages 3–5 and are more frequent among patients undergoing renal replacement therapy, mainly among those receiving hemodialysis therapy.
The prevalence of malnutrition has been reported in up to 54% of patients living with CKD, leading to a significant increase in morbidity and mortality (1–3). Nutritional screening is a preassessment method of nutritional status to identify patients at risk of malnutrition and, in turn, to indicate nutritional assessment for those with increased nutritional risk and/or probable malnutrition. Since the 1980s, several nutritional screening tools have been implemented in CKD (Figure 1).
Timeline of nutritional screening tools and diagnostic criteria used in populations with CKD and undergoing dialysis
Citation: Kidney News 16, 6
The subjective global assessment (SGA), originally developed by Detsky and colleagues in the 1980s (4), was adapted and validated in 1996 as a seven-point scale (7-point SGA) (5, 6). Recommended by clinical practice guidelines for regular nutritional assessment in patients with CKD and undergoing dialysis (7), this 7-point SGA is based on clinical history data (body weight, dietary intake, gastrointestinal symptoms, and functional capacity, as well as comorbidities related to nutritional needs) and includes a physical examination of body mass (subcutaneous fat and muscle) and the detection of edema. Studies (8, 9) have shown that low 7-point SGA scores are associated with a high risk of mortality in patients living with CKD and undergoing dialysis. In 1999, the dialysis malnutrition score (DMS) was developed (10), which used the original 7-point SGA scale and included a score from 1 to 5 for each item. Subsequently, the Malnutrition-Inflammation Score (MIS) questionnaire, a semiquantitative tool that is based on the subjective 7-point SGA and also includes objective parameters (body mass index, serum albumin, and total iron binding capacity) (11), has been extensively correlated in previous studies (11, 12) with hospital admission and mortality. MIS is a validated nutritional screening tool for patients with CKD and undergoing dialysis (11, 12) and has been recommended for routine use for the nutritional assessment of patients with kidney failure (7). The Dialysis Outcomes and Practice Patterns Study (9) used the quantitative modified SGA (m-SGA), developed in 2002, based on caregiver ratings of weight loss, appetite loss, gastrointestinal symptoms, and disease burden. Patients with a severe m-SGA score had significantly higher mortality risk compared with those with moderate or normal m-SGA scores.
An expert panel in 2008 (13) suggested using specific markers from four different categories—biochemistry, body mass, muscle mass, and dietary intake—for the clinical diagnosis of the so-called protein-energy wasting (PEW) syndrome. Three of these four categories should be included, with at least one being a biochemical marker. PEW is a complex syndrome that, combined with the inflammation, uremic toxicity, and endocrine-metabolic disorders of CKD, has been shown to significantly increase the mortality rate at a 5-year follow-up (13) (Figure 2).
Prevalence of PEW in patients with CKD
Citation: Kidney News 16, 6
Most recently in 2019, unified diagnostic criteria for disease-related malnutrition were proposed within the framework of the Global Leadership Initiative on Malnutrition (GLIM) (14). The GLIM approach includes one phenotypic criterion (low body mass index, unintentional body weight loss, or low muscle mass) and at least one etiologic criterion (reduced food intake, disease burden, or inflammation state) for diagnosing disease-related malnutrition. At present, the applicability of GLIM criteria in CKD and dialysis is still being developed. Further studies with large samples are warranted to validate GLIM criteria for the diagnosis of PEW.
In summary, the first step in detecting nutritional risk can be performed using well-established and validated nutritional screening tools, whereas nutritional assessment requires the combination of several parameters to diagnose PEW in populations with CKD and undergoing dialysis. A single marker by itself is not able to identify or diagnose nutritional disorders.
Footnotes
References
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Alvarez-Garcia G, et al. Comorbidity and nutritional status in adult with advanced chronic kidney disease influence the decision-making choice of renal replacement therapy modality: A retrospective 5-year study. Front Nutr 2023; 10:1105573. doi: 10.3389/fnut.2023.1105573
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Barril G, et al. Nutritional predictors of mortality after 10 years of follow-up in patients with chronic kidney disease at a multidisciplinary unit of advanced chronic kidney disease. Nutrients 2022;14:3848. doi: 10.3390/nu14183848
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Ikizler TA, et al. KDOQI Clinical Practice Guideline for Nutrition in CKD: 2020 Update. Am J Kidney Dis 2020; 76(Suppl 1):S1–S107. doi: 10.1053/j.ajkd.2020.05.006
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Chan M, et al. Malnutrition (subjective global assessment) scores and serum albumin levels, but not body mass index values, at initiation of dialysis are independent predictors of mortality: A 10-year clinical cohort study. J Ren Nutr 2012; 22:547–557. doi: 10.1053/j.jrn.2011.11.002
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Pifer TB, et al. Mortality risk in hemodialysis patients and changes in nutritional indicators: DOPPS. Kidney Int 2002; 62:2238–2245. doi: 10.1046/j.1523-1755.2002.00658.x
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Kalantar-Zadeh K, et al. A malnutrition-inflammation score is correlated with morbidity and mortality in maintenance hemodialysis patients. Am J Kidney Dis 2001; 38:1251–1263. doi: 10.1053/ajkd.2001.29222
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Amparo FC, et al. Diagnostic validation and prognostic significance of the Malnutrition-Inflammation Score in nondialyzed chronic kidney disease patients. Nephrol Dial 2015; 30:821–828. doi: 10.1093/ndt/gfu380
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Fouque D, et al. A proposed nomenclature and diagnostic criteria for protein-energy wasting in acute and chronic kidney disease. Kidney Int 2008; 73:391–398. doi: 10.1038/sj.ki.5002585
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Cederholm T, et al.; GLIM Core Leadership Committee; GLIM Working Group. GLIM criteria for the diagnosis of malnutrition—a consensus report from the global clinical nutrition community. Clin Nutr 2019; 38:1–9. doi: 10.1016/j.clnu.2018.08.002
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