Introduction
Background
“Malnutrition” describes both over and undernutrition. In the UK, the National Institute for Health and Care Excellence (NICE) define malnutrition as “a state in which a deficiency of nutrients such as energy, protein, vitamins and minerals causes measurable adverse effects on body composition, function or clinical outcome” in their Clinical Guideline (CG 32) [
1] and Quality Standard (QS24) [
2]. These guidelines suggest that patients at high risk of malnutrition should be screened and referred for specialist support if it is present.
Patients with kidney failure face a number of challenges to their nutritional balance [
3]. Uraemia itself inhibits appetite and reduces nutrient intake. Dialysis treatments result in the loss of small amounts of nutrients too. There are also other factors that tend to promote protein breakdown over protein synthesis. These include acidosis, insulin resistance and chronic inflammation. This latter factor can coexist with extensive atherosclerotic disease in a particularly toxic combination that is associated with increased mortality risk [
3]. The International Society of Renal Nutrition and Metabolism (ISRNM), recommend the term protein energy wasting (PEW) to describe the undernutrition that is prevalent in renal failure populations [
4], though more than one underlying cause may present in any individual.
Protein energy wasting is described in 20–40% of patients with stage 4–5 chronic kidney disease (CKD) [
3]. It is a more frequent finding in dialysis patients where it is described in 28–54% [
5] and is associated with reduced survival, poor healing, infection risk, impaired functional ability and reduced quality of life [
3].
Aim
This clinical practice guideline reviews existing recommendations from International Society for Renal Nutrition & Metabolism, European Society for Parenteral and Enteral Nutrition, Kidney Disease Improving Global Outcomes, American Society for Parenteral and Enteral Nutrition and European Renal Association/European Dialysis & Transplant Association [
6‐
10] and considers recent guidance on advanced kidney failure from NICE [
11] with the aim of reducing variation in practice.
Scope
This guideline has considered how to help adults with CKD stage 4 and 5.
We have not explored the evidence relating to kidney disease in children.
This guideline is intended for health care professionals and people with kidney disease.
Appraisal of evidence and development of recommendations
The modified GRADE system was used in accordance with the Renal Association’s “Clinical Practice Guideline Development Manual” [
12].
There is a two-level grading system for the strength of recommendations.
A Grade 1 recommendation is a strong recommendation to do (or not do) something, where the benefits clearly outweigh the risks (or vice versa) for most, if not all patients.
A Grade 2 recommendation is a weaker recommendation, where the risks and benefits are more closely balanced or are more uncertain.
Explicit methodology is used to describe the quality of evidence.
Grade A evidence means high-quality evidence that comes from consistent results from well-performed randomised controlled trials, or overwhelming evidence of some other sort (such as well-executed observational studies with very strong effects).
Grade B evidence means moderate-quality evidence from randomised trials that suffer from serious flaws in conduct, inconsistency, indirectness, imprecise estimates, reporting bias, or some combination of these limitations, or from other study designs with special strength.
Grade C evidence means low-quality evidence from observational studies, or from controlled trials with several very serious limitations.
Grade D evidence is based only on case studies or expert opinion.
Clinical issues covered
We considered how best to identify those at risk of undernutrition and how best to reduce this risk.
We used the HDAS database search tool that is accessible via Health Education England and NICE to identify information sources. This includes a number of search tools including Pub Med, EMBASE, CINAHL and Medline. This was most recently accessed in November 2018. Search terms included, “screening”, “kidney disease”, “nutrition”, “malnutrition”, “vitamin”, and other terms pertinent to dialysis as deemed necessary. We also searched the Cochrane library for relevant systematic reviews.
Summary of clinical practice guidelines
Identification of undernutrition in people with kidney disease (guidelines 1.1–1.3)
Guideline 1.1 – screening for risk of undernutrition in CKD
We suggest that patients with stages 4–5 CKD should be screened to identify those at risk of undernutrition (2C):
We suggest that screening should be performed (2D);
-
On admission then weekly for inpatients
-
At clinic review for outpatients with stage 4–5 CKD
-
2–3 monthly for stable haemodialysis patients
-
2–3 monthly for stable peritoneal dialysis patients
-
Screening should be performed earlier if their clinical condition changes
Guideline 1.2 – diagnosis of undernutrition in people with kidney disease
1.2.1 - We suggest that there should be a clear pathway for prompt referral to specialist renal dietitians when risk of undernutrition is identified. This pathway should include locally agreed timescales for formal assessment. (2D)
1.2.2 - We suggest that patients should be assessed by a specialist renal dietitian when they begin education about renal replacement treatment and within one month of starting dialysis or changing dialysis modality (2D)
1.2.3 - We suggest that formal nutritional assessments are carried out on those identified to be at risk by screening. These diagnostic assessments will typically be performed by specialist renal dietitians with support from the broader multidisciplinary team. (2B)
Guideline 1.3 - we recommend that in-patients at risk of malnutrition on screening are also considered at risk of refeeding syndrome. (1D)
Interventions to reduce the prevalence of undernutrition in people with kidney disease (guidelines 2.1–2.6)
Guideline 2.1 – dose of small solute removal to prevent anorexia
We recommend that dialysis dose meets recommended solute clearance index guidelines (e.g. URR, Kt/V). (1C)
Guideline 2.2 – correction of metabolic acidosis
We suggest that venous bicarbonate concentrations should be maintained in the normal range (2C)
Guideline 2.3 – daily dietary protein intake
We recommend a protein intake of:
-
0.8–1.0 g/kg ideal body weight (IBW)/day for patients with stage 4–5 CKD not on dialysis (1C)
-
1.1–1.4 g/kg IBW/day for patients treated on maintenance haemodialysis (1C)
-
1.0–1.2 g/kg IBW/day for patients treated with peritoneal dialysis (1C)
-
This should be accompanied by an adequate energy intake. (1C)
-
We do not believe there is sufficient evidence to routinely recommend low protein diets for people with progressive kidney disease (1C)
Guideline 2.4 – daily energy intake
We suggest a prescribed energy intake of:
-
30–40 kcal/kg IBW/day for all patients depending upon age and physical activity (2C).
-
We note that peritoneal dialysis patients are likely to absorb glucose from their dialysis fluid and this should be taken into account.
Guideline 2.5 – micronutrient supplementation in patients on dialysis
We suggest that water soluble vitamin supplements should be offered to patients on dialysis with a reduced nutrient intake or those that have unusually high levels of solute clearance on dialysis (e.g. daily or overnight haemodialysis). (2C)
We recommend that other micronutrients are supplemented only if there are symptoms consistent with deficiency and biochemical evidence of deficiency. (1C)
Interventions to treat undernutrition in people with kidney disease (guidelines 3.1–3.3)
Guideline 3.1 anabolic agents in kidney disease
We recommend that anabolic agents should not be used to treat undernutrition in people with kidney disease. (1C)
Guideline 3.2 – Oral nutritional supplements in patients who are undernourished
We recommend the use of oral nutritional supplements (ONS) when nutritional intake fails to increase, despite intervention and advice, and remains inadequate to meet energy and protein requirements. (1C)
Guideline 3.3 – enteral feeding in patients who are undernourished
We suggest that the use of enteral tube feeding is considered in selected cases if nutrient intake is suboptimal despite oral nutritional support recognising that there are significant risks and inconvenience associated with these forms of feeding (2C). It is important to consider the patient’s comorbidity, general condition and likely survival prospects before initiating enteral tube feeding.
Guideline 3.4 – parenteral nutritional support in patients who are undernourished
We suggest intradialytic parenteral nutrition (IDPN) in haemodialysis or intraperitoneal amino acids in peritoneal dialysis may be considered for selected cases when oral or enteral intake is suboptimal (2D).
Summary of audit measures
Audit Measure 1: The service should be able to demonstrate that there is a clear pathway for nutrition care that states how patients at risk of undernutrition will be identified, who they should be referred to and timescales for formal assessment.
Audit Measure 2: The service should be able to demonstrate that “at risk” patients were assessed by a specialist renal dietitian within the locally agreed timeframe.
Audit Measure 3: The service should be able to demonstrate that all patients commencing dialysis (or changing modality) are assessed by a specialist renal dietitian within four weeks.
Rationale for clinical practice guidelines
Identification of undernutrition in people with kidney disease (guidelines 1.1–1.3)
Guideline 1.1 – screening for risk of undernutrition in CKD
We suggest that patients with stages 4–5 CKD should be screened to identify those at risk of undernutrition (2C):
We suggest that screening should be performed (2D);
-
On admission then weekly for inpatients
-
At clinic review for outpatients with stage 4–5 CKD
-
2–3 monthly for stable haemodialysis patients
-
2–3 monthly for stable peritoneal dialysis patients
-
Screening should be performed earlier if their clinical condition changes
Guideline 1.2 – diagnosis of undernutrition in people with kidney disease
1.2.1 - We suggest that there should be a clear pathway for prompt referral to specialist renal dietitians when risk of undernutrition is identified. This pathway should include locally agreed timescales for formal assessment. (2D).
1.2.2 - We suggest that patients should be assessed by a specialist renal dietitian when they begin education about renal replacement treatment and within one month of starting dialysis or changing dialysis modality (2D).
1.2.3 - We suggest that formal nutritional assessments are carried out on those identified to be at risk by screening. These diagnostic assessments will typically be performed by specialist renal dietitians with support from the broader multidisciplinary team. (2B).
Rationale
Our recommendations aim to ensure that services have clear pathways for referral to specialist renal dietitians. These individuals should have received specialist training in the techniques used to diagnose undernutrition in people with kidney disease.
People deemed to be at risk of undernutrition should be referred for assessment. This uses more sophisticated techniques to determine whether or not undernutrition is present and how severe it is and decide to guide a treatment plan.
ASPEN use the following six evidence based criteria for nutritional assessment:
-
Insufficient energy intake
-
Weight loss
-
Loss of muscle mass
-
Loss of subcutaneous fat
-
Fluid accumulation that can sometimes mask weight loss
-
Diminished “functional status” as measured by hand grip strength.
The presence of two or more of these would lead to a diagnosis of undernutrition.
SGA includes gastrointestinal symptoms (appetite, anorexia, nausea, vomiting, diarrhoea), weight change in the preceding 6 months and last 2 weeks, evidence of functional impairment and a subjective visual assessment of subcutaneous tissue and muscle mass [
26].
Modern bioimpedance analysis or spectroscopy devices are primarily designed to assess fluid status but have also been used in nutritional assessment. They require training and expertise, but a wide variety of staff can be taught [
27].
Assessment should be carried out by a specialist renal dietitian with knowledge of renal disease and sufficient experience to know which of these tools will be most useful for each individual patient. Medical and nursing staff will also be involved in diagnosing the causes for malnutrition. Social workers, psychologists and community health teams may also have a role to play in individual cases.
Uraemic symptoms will need to be assessed to ensure that they are adequately controlled. If they are not, the reasons for this will need to be determined and rectified [
28‐
31].
Other systemic diseases, especially inflammatory conditions (infection, non-functioning transplants, etc.) and intestinal disease will need to be diagnosed and treated where possible [
32].
Dentition may need some attention to make it easier to chew food and address caries & gum disease.
Depression reduces food intake so this may require support or treatment if present [
33].
Changes in social circumstances may influence the availability of food.
Some medication can influence appetite and could be reviewed.
Nutritional status is known to deteriorate as chronic disease progresses [
34], and is a strong predictor for increased morbidity and mortality. Assessment of nutritional status should therefore be considered when patients begin education for kidney replacement treatment as part of their overall care as well as for potential intervention regarding salt, potassium, phosphate and protein / energy intake assessments [
25]. Dietetic assessment is needed at dialysis commencement [
18] and if the mode of dialysis changes. This is an important time to assess nutritional status and dietary knowledge in terms of potassium, phosphate, salt and fluid. It is also a good time to reassess the patient’s individualized nutritional care plan, prioritising which bits of information are most important for each person. More than one visit is likely to be needed. The advice given may change over time depending upon the response to dialysis and other changing circumstances.
For stable patients, nutritional changes are likely to be gradual after this [
28]. Screening should help to remind both front line staff and patients that nutritional status can change quickly. If there are concerns about weight loss, changes in physical appearance or reported reduced food intake between screening cycles, screening should be repeated earlier or advice sought from specialist renal dietitians. The importance of multidisciplinary working between doctors, nurses and specialist renal dietitians in this regard cannot be over-emphasised.
Guideline 1.3 - we recommend that in-patients at risk of malnutrition on screening are also considered at risk of refeeding syndrome. (1D)
Interventions to reduce the prevalence of undernutrition in people with kidney disease (guidelines 2.1–2.6)
Guideline 2.1 – dose of small solute removal to prevent anorexia
We recommend that dialysis dose meets recommended solute clearance index guidelines (e.g. URR, Kt/V).(1C)
Guideline 2.2 – correction of metabolic acidosis
We suggest that venous bicarbonate concentrations should be maintained in the normal range (2C)
Guideline 2.3 – daily dietary protein intake
We recommend a minimum protein intake of:
-
0.8–1.0 g/kg ideal body weight (IBW)/day for patients with stage 4–5 CKD not on dialysis (1C)
-
1.1 g/kg IBW/day for patients treated with haemodialysis (1C)
-
1.0–1.2 g/kg IBW/day for patients treated with peritoneal dialysis (1C)
-
This should be accompanied by an adequate energy intake. (1C)
-
We do not believe there is sufficient evidence to recommend low protein diets for people with progressive kidney failure (1C)
Guideline 2.4 – daily energy intake
We suggest a prescribed energy intake of
-
30–40 kcal/kg IBW/day for all patients depending upon age and physical activity (2C).
-
We note that peritoneal dialysis patients are likely to absorb glucose from their dialysis fluid and this should be taken into account.
Guideline 2.5 – micronutrient supplementation in patients on dialysis
We suggest that water soluble vitamin supplements should be offered to dialysis patients with a reduced nutrient intake or those that have unusually high levels of solute clearance on dialysis (e.g. daily or overnight haemodialysis). (2C)
We recommend that other micronutrients are supplemented only if there are symptoms consistent with deficiency and biochemical evidence of deficiency. (1C)
Interventions to treat undernutrition in people with kidney disease (guidelines 3.1–3.4)
Guideline 3.1 - anabolic agents in kidney disease
We recommend that anabolic agents should not be used to treat undernutrition in people with kidney disease. (1C)
Guideline 3.2 Oral nutritional supplements in patients who are undernourished
We recommend the use of oral nutritional supplements (ONS) when nutritional intake fails to increase, despite intervention and advice, and remains inadequate to meet energy and protein requirements. (1C)
Guideline 3.3 - enteral feeding in patients who are undernourished
We suggest that the use of enteral feeding is considered in selected cases if nutrient intake is suboptimal despite ONS recognising that there are significant risks and inconvenience associated with these forms of feeding (2C). It is important to also consider the patient’s comorbidity, general condition and likely survival prospects before initiating enteral feeding.
Guideline 3.4 - parenteral nutritional support in patients who are undernourished
We suggest intradialytic parenteral nutrition (IDPN) in haemodialysis or intraperitoneal amino acids in peritoneal dialysis may be considered for selected cases when oral or enteral intake is suboptimal (2D).
Intradialytic parenteral nutrition (IDPN) can be used as a form of nutrition support in maintenance patients on haemodialysis. The FINE study [
70] compared ONS to ONS and IDPN in a randomised controlled trial. Survival rates did not differ between the two groups, and both groups improved nutritional markers. The study did not report data on quality of life, hospital admission rates or length of stay. A subsequent systematic review set out to identify if IDPN improved survival, quality of life, or nutritional status [
71]. It concluded that there was insufficient evidence to demonstrate benefit or harm with the use of IDPN in malnourished haemodialysis patients. A more recent randomised controlled trial found a change in a biochemical marker but no improvement in quality of life scores or SGA rating [
72]. Despite the lack of evidence for widespread use of IDPN, it may be helpful in a small number of selected cases when other options have been exhausted.
Use of “total” parenteral nutrition is recommended as per BAPEN/ESPEN guidelines when the gut is non-functioning or inaccessible.
Intraperitoneal amino acid (IPAA) solutions use 1.1% amino acid-based solution in place of a dextrose-based peritoneal dialysate. Studies that have shown IPAA with bicarbonate buffered fluid increase protein synthesis [
73]. It appears that having the amino acid solution administered in a fed state helps to increase protein synthesis [
74]. The studies were short in duration and failed to see a significant improvement in nitrogen balance. In a 3-year, randomized controlled study, 60 malnourished CAPD patients were randomly assigned to either replace one daily exchange with IPAA or to continue with dextrose dialysate [
75]. Dietary protein intake increased in the IPAA group. Biochemical nutritional parameters stayed stable or increased in the IPAA group but decreased in the dextrose group. There was no effect on patient survival. As such, this product may have a place in the treatment of a small number of selected individuals.
Lay summary
Undernutrition is common in people with kidney disease. It is linked to problems that can affect quality of life and wellbeing. Based on the research that has been done, the risk of not being able to eat enough food to maintain usual weight is higher in people with kidney disease than in those without kidney disease.
We recommend that all people with advanced kidney disease have access to a specialist renal dietitian to help understand more about how to eat healthily. Diet affects several aspects of kidney disease and it can be tricky to find a balance between restricting things that can cause problems and taking enough of the things that are needed.
Kidney services should be able to look out for signs that undernutrition is developing and have a detailed plan about what to do should it be identified. If it looks as though this is happening, those affected should be given the opportunity to talk to a dietitian who is qualified to treat undernutrition in people with kidney disease.
Sometimes, there can be more than one reason for undernutrition, so several different specialists might need to work together to help. When someone cannot eat enough ordinary food to stay well nourished, supplements or other forms of additional nutrition may be recommended.
It appears that regular exercise is good for people having dialysis. It can help to preserve muscle function and makes people feel better.
Acknowledgements
This document has been externally reviewed by key stake holders according to the process described in the Clinical Practice Guidelines Development Policy Manual. The authors would like to express their gratitude to the British Dietetic Association Renal Nutrition Group for their thoughts and advice during the development of this guideline.
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