Abstract
This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:
This review aims to look at the benefits and harms of using oral protein‐based supplements to improve the nutritional state of patients with CKD requiring dialysis.
Background
Description of the condition
The number of people estimated to be receiving renal replacement therapy worldwide increased from 1.1 million during the 1990 to 2.618 million in 2010 (Liyanage 2015; Lysaght 2002). Malnutrition is common in patients with chronic kidney disease (CKD) on dialysis. A prospective cohort study by Tan 2016 found that more than half of hospitalised patients requiring haemodialysis (HD) were malnourished. In fact, malnutrition can already be demonstrated in about 10% of renal patients at the start of predialysis care (Westland 2015).
Several factors are thought to contribute to malnutrition in dialysis‐dependent patients. These include, but are not limited to, reduced oral intake and loss of appetite due to uraemic toxins, increased catabolism, low‐grade inflammation, oxidative stress, and the presence of other co‐morbidities (Burrowes 2003; Malgorzewicz 2016). An additional issue for hospitalised patients includes frequent fasting for tests and procedures.
Malnutrition is defined as a low‐nutrient intake or an intake that is inadequate for the nutritional needs of the individual (Fouque 2008a). Nutrition assessment tools frequently used in assessing malnutrition among dialysis patients include the Subjective Global Assessment (SGA) and the patient‐generated SGA (PG‐SGA) (Desbrow 2005; Detsky 1987). In dialysis patients, malnutrition has been strongly associated with increased mortality and hospitalisations, as well as poor quality of life (Dwyer 2002; Kalantar‐Zadeh 2001; Kalantar‐Zadeh 2011). Of the several clinical factors evaluated in the dialysis population, advanced age has been associated with a higher incidence of malnutrition (Kadiri 2011).
Description of the intervention
Dietary energy and protein intake of patients on maintenance HD are inadequate compared to the recommended standard of care, which can result in loss of lean body mass and malnutrition (Burrowes 2003; KDIGO 2012). The Kidney Disease Improving Global Outcomes (KDIGO) Guidelines recommend that individuals with CKD receive expert dietary advice and information in the context of an educational program that is tailored to the severity of the disease (KDIGO 2012).
Oral nutritional (protein and calorie) supplements are often provided to patients whose oral intake is otherwise insufficient to meet their energy needs (Jensen 2013). They are typically formulated as a combination of macro and micronutrients, and are used in conjunction with expert advice from dietitians (Jensen 2013; Schneyder 2014). Standard oral nutritional supplements are best taken as snacks between meals to complement normal meals (Schneyder 2014).
How the intervention might work
Diet and enteral nutritional support that targets dietary protein intake have previously been reported to mitigate malnutrition (Kalantar‐Zadeh 2011). However, appropriate nutritional supplements can be difficult to administer in dialysis patients. In addition to factors such as a reduced appetite, poor nutrition is further compounded by the dictates of a stringent fluid restriction, especially in patients with minimal urine output, and electrolyte imbalance. High protein foods such as meat, dairy and nuts carry a high phosphate load, and 'healthy' foods such as fruit and vegetables are often restricted because of their potassium content. Oral nutritional supplements therefore must be suitably adjusted in order to be taken safely and repeatedly. As such, renal‐specific supplements have a higher protein and energy content, with a lower potassium and phosphate content (Williams 2009). Examples of protein‐based oral nutritional supplements prescribed to dialysis patients include Nepro, Novasource Renal, Renilon, and Suplena (Fouque 2008b; Shah 2014). Protein isolates which include, but are not limited to, whey protein and soy protein, have also been used as a source of protein supplementation in dialysis patients (Tomayko 2015).
Reported benefits of oral nutritional supplements in HD patients include improvement in muscle quality leading to improvements in physical function without an increase in lean mass (Franch 2009; Tomayko 2015). The use of oral nutritional supplements may also provide quicker nutritional repletion and a trend towards a reduced number of days of hospitalisation (Wilson 2001). Reported harms include adverse biochemistry (hyperkalaemia, hyperphosphataemia), intolerability due to taste, and cost that is often borne by the patient (Williams 2009).
Why it is important to do this review
The benefits of protein‐based oral supplements in patients with CKD, particularly those on dialysis, have long been debated. However, several recent, large, observational studies have demonstrated that the use of oral intra‐dialytic nutritional supplements is associated with a reduction in mortality of up to 35% in HD patients (Lacson 2012; Weiner 2014).
The cost of oral nutritional supplements is usually borne by the patients. The increasing expenditure of such supplements further complicates the picture. A recent systematic review by Elia 2016, based mostly on retrospective cost analyses, indicated that the use of nutritional supplements in the community and care homes produce an overall cost advantage. This cost advantage was primarily from reduced hospitalisations and length of stays, but there were also several clinically relevant outcomes favouring oral nutritional supplements reported, including an improved quality of life and reduced infections (Elia 2016). Focusing on the subgroup analyses comparing the use of oral nutritional supplements to no oral nutritional supplements, there is a median cost saving of 11.5% (Elia 2016).
Baldwin 2011 conducted a systematic review examining several interventions in addition to dietary advice in adults with disease‐related malnutrition. One intervention arm of this review compared the outcome of dietary advice with dietary advice plus an oral nutritional supplement (Baldwin 2011). Improvements in mid‐arm muscle circumference, triceps skinfold, and grip strength were demonstrated in the supplement group (Baldwin 2011). However, for the two latter outcomes, there was significant heterogeneity in the pooled analysis (Baldwin 2011). In this intervention arm though, only three of the 16 studies included involved patients on dialysis (Baldwin 2011). Furthermore, as this review was completed in 2011 and the terms 'dialysis or CKD' were not specifically used in their search terms, there may be studies specific to dialysis patients available now that were not included in their analysis (Baldwin 2011).
The focus of this review is the role of oral protein‐based supplements in patients with CKD on dialysis. Although the above reviews by Elia 2016 and Baldwin 2011 are not specific to dialysis patients, it certainly raises the question whether potential benefits in clinical outcomes and cost are applicable to the dialysis population more generally. Currently, there are no consensus guidelines regarding the use of oral nutritional supplements in dialysis patients. As such, the availability and prescription of oral protein‐based supplements varies widely between dialysis units. Understanding the relevant benefits, cost restrictions and potential for harm with their use will likely lead to a more consistent approach.
Objectives
This review aims to look at the benefits and harms of using oral protein‐based supplements to improve the nutritional state of patients with CKD requiring dialysis.
Methods
Criteria for considering studies for this review
Types of studies
All randomised controlled trials (RCTs) and quasi‐RCTs (RCTs in which allocation to treatment was obtained by alternation, use of alternate medical records, date of birth or other predictable methods) comparing oral protein‐based supplements to no oral nutritional supplements will be included without language restriction.
If the search strategy reveals a large number of trial comparing different types of oral protein‐based supplements, consideration will be given to examine the outcomes with these comparisons in separate analyses.
Types of participants
We will include adults with CKD on dialysis, which encompasses both HD and peritoneal dialysis (PD).
Studies of patients with kidney disease not requiring dialysis, including conservative care and kidney transplant recipients, will be excluded.
Types of interventions
Studies comparing oral protein‐based supplements to no oral protein‐based supplements or placebo will be included. These supplements include renal‐specific supplements such as Nepro, Novasource Renal, Renilon, and Suplena, as well as protein isolates including whey and soy protein. Studies where dietary advice is provided to the non‐intervention group will be included.
Types of outcome measures
Assessment of nutritional status in patients receiving dialysis takes into account multiple factors and no single measure of nutritional status is sufficient on its own. We have therefore included both physical and biochemical measures of nutritional status as outcomes and will report on these as the data allows.
Primary outcomes
Changes in serum albumin level
Other measure of nutritional status (such as weight gain, serum prealbumin level, anthropometric measurements, e.g. triceps skin fold thickness and arm muscle circumference, grip strength)
Mortality
Intolerance to therapy
Secondary outcomes
Quality of life
Cost
Markers of inflammation
Biochemical adverse effects such as hyperkalaemia or hyperphosphataemia
Search methods for identification of studies
Electronic searches
We will search the Cochrane Kidney and Transplant Specialised Register through contact with the Information Specialist using search terms relevant to this review. The Cochrane Kidney and Transplant's Specialised Register contains studies identified from several sources.
Monthly searches of the Cochrane Central Register of Controlled Trials (CENTRAL)
Weekly searches of MEDLINE OVID SP
Handsearching of kidney‐related journals and the proceedings of major kidney conferences
Searching of the current year of EMBASE OVID SP
Weekly current awareness alerts for selected kidney and transplant journals
Searches of the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.
Studies contained in the Specialised Register are identified through search strategies for CENTRAL, MEDLINE, and EMBASE based on the scope of Cochrane Kidney and Transplant. Details of these strategies, as well as a list of handsearched journals, conference proceedings and current awareness alerts, are available in the Specialised Register section of information about Cochrane Kidney and Transplant.
See Appendix 1 for search terms used in strategies for this review.
Searching other resources
Reference lists of review articles, relevant studies and clinical practice guidelines
Letters seeking information about unpublished or incomplete studies to investigators known to be involved in previous studies
Clinical trial registries for studies not yet completed.
Data collection and analysis
Selection of studies
The search strategy described will be used to obtain titles and abstracts of studies that may be relevant to the review. The titles and abstracts will be screened independently by two authors, who will discard studies that are not applicable; however studies and reviews that might include relevant data or information on studies will be retained initially. Two authors will independently assess retrieved abstracts and, if necessary the full text, of these studies to determine which studies satisfy the inclusion criteria. Any differences will be resolved by discussion and where necessary, by consultation with a third author.
Data extraction and management
Two authors will independently extract data using ‘data extraction forms’ which will be developed. Studies reported in non‐English language journals will be translated before assessment. Where more than one publication of one study exists, reports will be grouped together and the publication with the most complete data will be used in the analyses. Where relevant outcomes are only published in earlier versions these data will be used. Any discrepancy between published versions will be highlighted.
Assessment of risk of bias in included studies
The following items will be independently assessed by two authors using the risk of bias assessment tool (Higgins 2011) (see Appendix 2).
Was there adequate sequence generation (selection bias)?
Was allocation adequately concealed (selection bias)?
-
Was knowledge of the allocated interventions adequately prevented during the study?
Participants and personnel (performance bias)
Outcome assessors (detection bias)
Were incomplete outcome data adequately addressed (attrition bias)?
Are reports of the study free of suggestion of selective outcome reporting (reporting bias)?
Was the study apparently free of other problems that could put it at a risk of bias?
Measures of treatment effect
For dichotomous outcomes (e.g. mortality, episodes of hyperkalaemia) results will be expressed as risk ratio (RR) with 95% confidence intervals (CI). Where continuous scales of measurement are used to assess the effects of treatment (e.g. change in serum albumin levels, anthropometric measures and weight), the mean difference (MD) will be used, or the standardised mean difference (SMD) if different scales have been used.
Unit of analysis issues
Studies with non‐standard designs will be analysed in this review using the recommended methods for data extraction and analysis described by The Cochrane Collaboration (Higgins 2011).
When considering cross‐over studies, we will only include data for end points reported during the first period of study in studies in which the order of receiving treatments was randomised.
When considering studies with multiple treatment groups, we will attempt to combine all relevant experimental intervention groups of the study into a single group and to combine all relevant control intervention groups into a single control group to enable a single pair‐wise comparison.
Cluster‐randomised trials will be analysed using a statistical analysis that properly accounts for the cluster design as recommended in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011).
Dealing with missing data
Any further information required from the original author will be requested by written correspondence (e.g. emailing and/or writing to corresponding author/s) and any relevant information obtained in this manner will be included in the review. Evaluation of important numerical data such as screened, randomised patients as well as intention‐to‐treat, as‐treated and per‐protocol population will be carefully performed. Attrition rates, for example drop‐outs, losses to follow‐up and withdrawals will be investigated. Issues of missing data and imputation methods will be critically appraised (Higgins 2011).
Assessment of heterogeneity
We will first assess the heterogeneity by visual inspection of the forest plot. Heterogeneity will then be analysed using a Chi2 test on N‐1 degrees of freedom, with an alpha of 0.05 used for statistical significance and with the I2 test (Higgins 2003). A guide to the interpretation of I2 values will be as follows.
0% to 40%: might not be important
30% to 60%: may represent moderate heterogeneity
50% to 90%: may represent substantial heterogeneity
75% to 100%: considerable heterogeneity.
The importance of the observed value of I2 depends on the magnitude and direction of treatment effects and the strength of evidence for heterogeneity (e.g. P‐value from the Chi2 test, or a confidence interval for I2) (Higgins 2011).
Assessment of reporting biases
If possible, funnel plots will be used to assess for the potential existence of small study bias (Higgins 2011).
Data synthesis
Data will be pooled using the random‐effects model but the fixed‐effect model will also be used to ensure robustness of the model chosen and susceptibility to outliers.
Subgroup analysis and investigation of heterogeneity
Subgroup analysis will be used to explore possible sources of heterogeneity (e.g. participants, interventions and study quality). Heterogeneity among participants could be related to age, co‐morbidities, severity of malnutrition (low versus high baseline albumin level), and PD versus HD. Furthermore, patients with reduced food intake may be more likely to benefit from the intervention than those whose intake is considered adequate. Therefore, subgroup analysis of studies that include patients with reduced versus adequate intake will be performed. Heterogeneity in treatments could be related to dose, type and duration of protein‐based oral supplements. Adverse effects will be tabulated and assessed with descriptive techniques. Where possible, the risk difference with 95% CI will be calculated for each adverse effect in the treatment group compared to placebo.
Sensitivity analysis
We will perform sensitivity analyses in order to explore the influence of the following factors on effect size.
Repeating the analysis excluding unpublished studies
Repeating the analysis taking account of risk of bias, as specified
Repeating the analysis excluding any very long or large studies to establish how much they dominate the results
Repeating the analysis excluding studies using the following filters: diagnostic criteria, language of publication, source of funding (industry versus other), and country.
'Summary of findings' tables
We will present the main results of the review in 'Summary of findings' tables. These tables present key information concerning the quality of the evidence, the magnitude of the effects of the interventions examined, and the sum of the available data for the main outcomes (Schunemann 2011a). The 'Summary of findings' tables also include an overall grading of the evidence related to each of the main outcomes using the GRADE (Grades of Recommendation, Assessment, Development and Evaluation) approach (GRADE 2008). The GRADE approach defines the quality of a body of evidence as the extent to which one can be confident that an estimate of effect or association is close to the true quantity of specific interest. The quality of a body of evidence involves consideration of within‐trial risk of bias (methodological quality), directness of evidence, heterogeneity, precision of effect estimates and risk of publication bias (Schunemann 2011b). We plan to present the following outcomes in the 'Summary of findings' tables.
Changes in serum albumin level
Other measures of nutritional status (such as weight gain, serum prealbumin level, anthropometric measurements, e.g. triceps skin fold thickness and arm muscle circumference, grip strength)
Mortality
Intolerance to therapy
Quality of life
Cost
Markers of inflammation
Biochemical adverse effects such as hyperkalaemia or hyperphosphataemia.
These outcomes will be presented in two tables.
Acknowledgements
The Authors wish to acknowledge the assistance of the Cochrane Kidney and Transplant's Group's Editors and referees, and the Information Specialist.
Appendices
Appendix 1. Electronic search strategies
| Database | Search terms |
| CENTRAL |
|
| MEDLINE |
|
| EMBASE |
|
Appendix 2. Risk of bias assessment tool
| Potential source of bias | Assessment criteria |
|
Random sequence generation Selection bias (biased allocation to interventions) due to inadequate generation of a randomised sequence |
Low risk of bias: Random number table; computer random number generator; coin tossing; shuffling cards or envelopes; throwing dice; drawing of lots; minimisation (minimisation may be implemented without a random element, and this is considered to be equivalent to being random). |
| High risk of bias: Sequence generated by odd or even date of birth; date (or day) of admission; sequence generated by hospital or clinic record number; allocation by judgement of the clinician; by preference of the participant; based on the results of a laboratory test or a series of tests; by availability of the intervention. | |
| Unclear: Insufficient information about the sequence generation process to permit judgement. | |
|
Allocation concealment Selection bias (biased allocation to interventions) due to inadequate concealment of allocations prior to assignment |
Low risk of bias: Randomisation method described that would not allow investigator/participant to know or influence intervention group before eligible participant entered in the study (e.g. central allocation, including telephone, web‐based, and pharmacy‐controlled, randomisation; sequentially numbered drug containers of identical appearance; sequentially numbered, opaque, sealed envelopes). |
| High risk of bias: Using an open random allocation schedule (e.g. a list of random numbers); assignment envelopes were used without appropriate safeguards (e.g. if envelopes were unsealed or non‐opaque or not sequentially numbered); alternation or rotation; date of birth; case record number; any other explicitly unconcealed procedure. | |
| Unclear: Randomisation stated but no information on method used is available. | |
|
Blinding of participants and personnel Performance bias due to knowledge of the allocated interventions by participants and personnel during the study |
Low risk of bias: No blinding or incomplete blinding, but the review authors judge that the outcome is not likely to be influenced by lack of blinding; blinding of participants and key study personnel ensured, and unlikely that the blinding could have been broken. |
| High risk of bias: No blinding or incomplete blinding, and the outcome is likely to be influenced by lack of blinding; blinding of key study participants and personnel attempted, but likely that the blinding could have been broken, and the outcome is likely to be influenced by lack of blinding. | |
| Unclear: Insufficient information to permit judgement | |
|
Blinding of outcome assessment Detection bias due to knowledge of the allocated interventions by outcome assessors. |
Low risk of bias: No blinding of outcome assessment, but the review authors judge that the outcome measurement is not likely to be influenced by lack of blinding; blinding of outcome assessment ensured, and unlikely that the blinding could have been broken. |
| High risk of bias: No blinding of outcome assessment, and the outcome measurement is likely to be influenced by lack of blinding; blinding of outcome assessment, but likely that the blinding could have been broken, and the outcome measurement is likely to be influenced by lack of blinding. | |
| Unclear: Insufficient information to permit judgement | |
|
Incomplete outcome data Attrition bias due to amount, nature or handling of incomplete outcome data. |
Low risk of bias: No missing outcome data; reasons for missing outcome data unlikely to be related to true outcome (for survival data, censoring unlikely to be introducing bias); missing outcome data balanced in numbers across intervention groups, with similar reasons for missing data across groups; for dichotomous outcome data, the proportion of missing outcomes compared with observed event risk not enough to have a clinically relevant impact on the intervention effect estimate; for continuous outcome data, plausible effect size (difference in means or standardised difference in means) among missing outcomes not enough to have a clinically relevant impact on observed effect size; missing data have been imputed using appropriate methods. |
| High risk of bias: Reason for missing outcome data likely to be related to true outcome, with either imbalance in numbers or reasons for missing data across intervention groups; for dichotomous outcome data, the proportion of missing outcomes compared with observed event risk enough to induce clinically relevant bias in intervention effect estimate; for continuous outcome data, plausible effect size (difference in means or standardized difference in means) among missing outcomes enough to induce clinically relevant bias in observed effect size; ‘as‐treated’ analysis done with substantial departure of the intervention received from that assigned at randomisation; potentially inappropriate application of simple imputation. | |
| Unclear: Insufficient information to permit judgement | |
|
Selective reporting Reporting bias due to selective outcome reporting |
Low risk of bias: The study protocol is available and all of the study’s pre‐specified (primary and secondary) outcomes that are of interest in the review have been reported in the pre‐specified way; the study protocol is not available but it is clear that the published reports include all expected outcomes, including those that were pre‐specified (convincing text of this nature may be uncommon). |
| High risk of bias: Not all of the study’s pre‐specified primary outcomes have been reported; one or more primary outcomes is reported using measurements, analysis methods or subsets of the data (e.g. sub‐scales) that were not pre‐specified; one or more reported primary outcomes were not pre‐specified (unless clear justification for their reporting is provided, such as an unexpected adverse effect); one or more outcomes of interest in the review are reported incompletely so that they cannot be entered in a meta‐analysis; the study report fails to include results for a key outcome that would be expected to have been reported for such a study. | |
| Unclear: Insufficient information to permit judgement | |
|
Other bias Bias due to problems not covered elsewhere in the table |
Low risk of bias: The study appears to be free of other sources of bias. |
| High risk of bias: Had a potential source of bias related to the specific study design used; stopped early due to some data‐dependent process (including a formal‐stopping rule); had extreme baseline imbalance; has been claimed to have been fraudulent; had some other problem. | |
| Unclear: Insufficient information to assess whether an important risk of bias exists; insufficient rationale or evidence that an identified problem will introduce bias. |
Contributions of authors
Draft the protocol: JYM
Study selection: JYM, SWC, MR
Extract data from studies: JYM, SWC
Enter data into RevMan: JYM
Carry out the analysis: JYM, SWC
Interpret the analysis: JYM, SWC, MR, LM, AMD, MC, SG
Draft the final review: JYM, SWC, MR, LM, AMD, MC, SG
Disagreement resolution: LM
Update the review: JYM
Declarations of interest
None known
New
References
Additional references
- Baldwin C, Weekes CE. Dietary advice with or without oral nutritional supplements for disease‐related malnutrition in adults. Cochrane Database of Systematic Reviews 2011, Issue 9. [DOI: 10.1002/14651858.CD002008.pub4] [DOI] [PMC free article] [PubMed] [Google Scholar]
- Burrowes JD, Larive B, Cockram DB, Dwyer J, Kusek JW, McLeroy S, et al. Effects of dietary intake, appetite, and eating habits on dialysis and non‐dialysis treatment days in hemodialysis patients: cross‐sectional results from the HEMO study. Journal of Renal Nutrition 2003;13(3):191‐8. [MEDLINE: ] [DOI] [PubMed] [Google Scholar]
- Desbrow B, Bauer J, Blum C, Kandasamy A, McDonald A, Montgomery K. Assessment of nutritional status in hemodialysis patients using patient‐generated subjective global assessment. Journal of Renal Nutrition 2005;15(2):211‐6. [MEDLINE: ] [DOI] [PubMed] [Google Scholar]
- Detsky AS, McLaughlin JR, Baker JP, Johnston N, Whittaker S, Mendelson RA, et al. What is subjective global assessment of nutritional status?. Jpen: Journal of Parenteral & Enteral Nutrition 1987;11(1):8‐13. [MEDLINE: ] [DOI] [PubMed] [Google Scholar]
- Dwyer JT, Larive B, Leung J, Rocco M, Burrowes JD, Chumlea WC, et al. Nutritional status affects quality of life in hemodialysis (HEMO) study patients at baseline. Journal of Renal Nutrition 2002;12(4):213‐23. [MEDLINE: ] [DOI] [PubMed] [Google Scholar]
- Elia M, Normand C, Laviano A, Norman K. A systematic review of the cost and cost effectiveness of using standard oral nutritional supplements in community and care home settings. Clinical Nutrition 2016;35(1):125‐37. [MEDLINE: ] [DOI] [PubMed] [Google Scholar]
- Fouque D, Kalantar‐Zadeh K, Kopple J, Cano N, Chauveau P, Cuppari L, et al. A proposed nomenclature and diagnostic criteria for protein‐energy wasting in acute and chronic kidney disease.[Erratum appears in Kidney Int. 2008 Aug;74(3):393 Note: Trevinho‐Becerra, A [corrected to Trevino‐Becerra, A]]. Kidney International 2008;73(4):391‐8. [MEDLINE: ] [DOI] [PubMed] [Google Scholar]
- Fouque D, McKenzie J, Mutsert R, Azar R, Teta D, Plauth M, et al. Use of a renal‐specific oral supplement by haemodialysis patients with low protein intake does not increase the need for phosphate binders and may prevent a decline in nutritional status and quality of life. Nephrology Dialysis Transplantation 2008;23(9):2902‐10. [MEDLINE: ] [DOI] [PubMed] [Google Scholar]
- Franch HA. Nutrition and muscle catabolism in maintenance hemodialysis: does feeding make muscle cells selective self‐eaters?. Journal of Renal Nutrition 2009;19(1):86‐90. [MEDLINE: ] [DOI] [PMC free article] [PubMed] [Google Scholar]
- Guyatt GH, Oxman AD, Vist GE, Kunz R, Falck‐Ytter Y, Alonso‐Coello P, et al. GRADE: an emerging consensus on rating quality of evidence and strength of recommendations. BMJ 2008;336(7650):924‐6. [MEDLINE: ] [DOI] [PMC free article] [PubMed] [Google Scholar]
- Higgins JP, Thompson SG, Deeks JJ, Altman DG. Measuring inconsistency in meta‐analyses. BMJ 2003;327(7414):557‐60. [MEDLINE: ] [DOI] [PMC free article] [PubMed] [Google Scholar]
- Higgins JP, Green S (editors). Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 [updated March 2011]. The Cochrane Collaboration, 2011. Available from www.cochrane‐handbook.org.
- Jensen GL. Oral nutritional supplementation. American Journal of Managed Care 2013;19(2):119‐20. [MEDLINE: ] [PubMed] [Google Scholar]
- Kadiri Mel M, Nechba RB, Oualim Z. Factors predicting malnutrition in hemodialysis patients. Saudi Journal of Kidney Diseases & Transplantation 2011;22(4):695‐704. [MEDLINE: ] [PubMed] [Google Scholar]
- Kalantar‐Zadeh K, Kopple JD, Block G, Humphreys MH. A malnutrition‐inflammation score is correlated with morbidity and mortality in maintenance hemodialysis patients. American Journal of Kidney Diseases 2001;38(6):1251‐63. [MEDLINE: ] [DOI] [PubMed] [Google Scholar]
- Kalantar‐Zadeh K, Cano NJ, Budde K, Chazot C, Kovesdy CP, Mak RH, et al. Diets and enteral supplements for improving outcomes in chronic kidney disease. Nature Reviews Nephrology 2011;7(7):369‐84. [MEDLINE: ] [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kidney Disease: Improving Global Outcomes (KDIGO) CKD Work Group. KDIGO 2012 clinical practice guideline for the evaluation and management of chronic kidney disease. Kidney International Supplements 2013;3(1):1‐150. [EMBASE: 369856107] [Google Scholar]
- Lacson E Jr, Wang W, Zebrowski B, Wingard R, Hakim RM. Outcomes associated with intradialytic oral nutritional supplements in patients undergoing maintenance hemodialysis: a quality improvement report. American Journal of Kidney Diseases 2012;60(4):591‐600. [MEDLINE: ] [DOI] [PubMed] [Google Scholar]
- Liyanage T, Ninomiya T, Jha V, Neal B, Patrice HM, Okpechi I, et al. Worldwide access to treatment for end‐stage kidney disease: a systematic review. Lancet 2015;385(9981):1975‐82. [MEDLINE: ] [DOI] [PubMed] [Google Scholar]
- Lysaght MJ. Maintenance dialysis population dynamics: current trends and long‐term implications. Journal of the American Society of Nephrology 2002;13 Suppl 1:S37‐40. [MEDLINE: ] [PubMed] [Google Scholar]
- Malgorzewicz S, Chmielewski M, Kaczkan M, Borek P, Lichodziejewska‐Niemierko M, Rutkowski B. Nutritional predictor of mortality in prevalent peritoneal dialysis patients. Acta Biochimica Polonica 2016;63(1):111‐5. [DOI: 10.18388/abp.2015_1070] [DOI] [PubMed] [Google Scholar]
- Schneyder A. Malnutrition and nutritional supplements. Australian Prescriber 2014;37(4):120‐3. [EMBASE: 373717315] [Google Scholar]
- Schünemann HJ, Oxman AD, Higgins JP, Vist GE, Glasziou P, Guyatt GH. Chapter 11: Presenting results and 'Summary of findings' tables. In: Higgins JP, Green S (editors). Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 [updated March 2011]. The Cochrane Collaboration, 2011. Available from www.cochrane‐handbook.org.
- Schünemann HJ, Oxman AD, Higgins JP, Deeks JJ, Glasziou P, Guyatt GH. Chapter 12: Interpreting results and drawing conclusions. In: Higgins JP, Green S (editors). Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 [updated March 2011]. The Cochrane Collaboration, 2011. Available from www.cochrane‐handbook.org.
- Shah AB, Shah RA, Chaudhari A, Shinde N. Therapeutic effects of oral nutritional supplements during haemodialysis: physician's experience. Journal of the Association of Physicians of India 2014;62(12):30‐4. [MEDLINE: ] [PubMed] [Google Scholar]
- Tan SK, Loh YH, Choong LH, Suhail SM. Subjective global assessment for nutritional assessment of hospitalized patients requiring haemodialysis ‐ a prospective cohort study. Nephrology 2016;21(11):944‐9. [MEDLINE: ] [DOI] [PubMed] [Google Scholar]
- Tomayko EJ, Kistler BM, Fitschen PJ, Wilund KR. Intradialytic protein supplementation reduces inflammation and improves physical function in maintenance hemodialysis patients. Journal of Renal Nutrition 2015;25(3):276‐83. [MEDLINE: ] [DOI] [PubMed] [Google Scholar]
- Weiner DE, Tighiouart H, Ladik V, Meyer KB, Zager PG, Johnson DS. Oral intradialytic nutritional supplement use and mortality in hemodialysis patients. American Journal of Kidney Diseases 2014;63(2):276‐85. [MEDLINE: ] [DOI] [PubMed] [Google Scholar]
- Westland GJ, Grootendorst DC, Halbesma N, Dekker FW, Verburgh CA. The nutritional status of patients starting specialized predialysis care. Journal of Renal Nutrition 2015;25(3):265‐70. [MEDLINE: ] [DOI] [PubMed] [Google Scholar]
- Williams RF, Summers AM. Do hemodialysis patients prefer renal‐specific or standard oral nutritional supplements?. Journal of Renal Nutrition 2009;19(2):183‐8. [MEDLINE: ] [DOI] [PubMed] [Google Scholar]
- Wilson B, Fernandez‐Madrid A, Hayes A, Hermann K, Smith J, Wassell A. Comparison of the effects of two early intervention strategies on the health outcomes of malnourished hemodialysis patients. Journal of Renal Nutrition 2001;11(3):166‐71. [MEDLINE: ] [DOI] [PubMed] [Google Scholar]