Nutritional management in pre-dialysis chronic kidney disease : an investigation of methods for nutritional assessment and intervention in pre-dialysis chronic kidney disease

Campbell, Katrina Louise (2007) Nutritional management in pre-dialysis chronic kidney disease : an investigation of methods for nutritional assessment and intervention in pre-dialysis chronic kidney disease. PhD thesis, Queensland University of Technology.


Malnutrition is present in up to 48% of chronic kidney disease patients on the initiation of renal replacement therapy (dialysis)1. At this time, malnutrition is an independent and significant predictor of morbidity and mortality2. As a consequence of progressive deterioration in kidney function, symptoms of decreased appetite and reduced intake are common factors leading to the decline in nutritional status3. However, at present there is little evidence to inform nutrition assessment and intervention for pre-dialysis chronic kidney disease (CKD). The purpose of this study was to provide evidence for the nutritional management of CKD patients prior to dialysis with an aim to optimise nutritional status. To address this, an investigation comprising of two phases examining nutrition assessment and intervention in a sample of pre-dialysis Stage IV and V CKD patients was undertaken. Both phases of the study were conducted through Royal Brisbane and Women’s Hospital (RBWH) Department of Renal Medicine pre-dialysis clinic. Participants met the following criteria: adult (&gt18 years) Glomerular Filtration Rate (GFR) &lt30ml/min CKD, not previously seen by a dietitian for Stage IV CKD, absence of communication or intellectual impairment inhibiting their ability to undertake the intervention and an absence of malnutrition from a cause other than CKD. Phase I was a cross-sectional investigation into the performance of a range of tools assessing nutrition status, conducted at baseline of Phase II. Phase II was a randomisedcontrolled trial designed to determine if providing individual nutrition counselling with regular telephone follow-up resulted in improved body composition, nutritional status, dietary intake and quality of life, compared with standard care. A range of intermediate, clinical and patient-centred outcome measures were collected at baseline and twelve weeks. Body composition was measured by total body potassium counting (TBK), considered a gold-standard measure of body cell mass (BCM, the body’s functional metabolising tissue). Nutritional status was measured using Subjective Global Assessment (SGA) and a number of modified versions of SGA, 7-point SGA, Malnutrition Inflammation Score (MIS) and the scored Patient-Generated Subjective Global Assessment (PG-SGA). Dietary intake was measured using 3-day food records. Quality of life was measured by Kidney Disease Quality of Life Short Form version 1.3 (KDQOL-SFTM v1.3 © RAND University), combining the Short Form-36 (SF-36), with a kidney disease-specific module4. Statistical analysis was carried out using SPSS Version 13 (SPSS Inc, Chicago, IL, USA). Phase I analysis was based on descriptive and bi-variate statistics, including chi-square, t-test and ANOVA. For phase II, change variables (Week 12 – Week 0) were created for the outcome measures (BCM, SGA tools, dietary intake (energy and protein) and the 18 KDQOL-SFTM subscales). The assessment of change in outcome measures by treatment group was undertaken by ANCOVA, adjusting for baseline values. Further multivariate analysis (ANCOVA and MANCOVA models) were created for outcome variables when confounding variables were identified and adjusted for. In Phase I, 56 patients (Male n=34; age mean (±SD) 70.7 (±14.0); GFRMDRD 22.4 (±6.5) mL/min) underwent baseline assessment. In this population the prevalence of malnutrition was 19.6% (n=11, SGA B; no C ratings). Malnutrition was associated with lower body cell mass (mean BCM, 26.3 vs. 33.4 kg p=0.007), body weight (64.8 vs. 76.1 kg p=0.042), BMI (23.7 vs. 27.6 kg/m2 p=0.015) and greater weight loss over previous 6 months (-6.2 vs. -0.1 kg p=0.004). Body cell mass indexed for height (BCM-I kg/m3.5) had a relationship with MIS (r=-0.27 p=0.063) and scored PG-SGA (r=-0.27 p=0.060), but not with 7-point SGA (F(4) 2.24 p=0.080). PG-SGA best discriminated malnutrition based on a BCM-I cut-off of &lt5.25kg/ m3.5 of all the modified SGA tools. The scored PG-SGA including the global SGA rating is recommended for use in pre-dialysis CKD. In Phase II, 50 patients, (Male n=31 (62.0%); age 69.7 (±12.0) years; GFRMDRD 22.1 (±6.9) ml/min) completed the 12 week study period (intervention n=24; standard care n=26). At 12 weeks, there was a clinically significant improvement in all outcome measures in the intervention group. There was a 3.9% (95% CI, -1.0 to 8.7%) mean difference in change for Body Cell Mass between the treatment groups, represented by a significant decrease in the standard care group and maintenance in the intervention group. Nutritional status measured by SGA improved or was maintained (24/24) in the intervention group, however, decreased in 14% (4/26) of the standard care group. Energy intake significantly improved in the intervention group resulting in a mean difference in change of 17.7kJ/kg (8.2 to 27.2 kJ/kg). Quality of life improved significantly in 10 of the 18 sub-scales in the intervention group. Significant effect modification for gender was apparent for many of the outcome variables, with females responding most significantly to the intervention treatment. This study concluded that, overall, structured nutrition intervention limits the deterioration in nutritional status, improves dietary intake and quality of life in patients with CKD prior to the onset of renal replacement therapy. This thesis makes a significant contribution to the evidence base for nutritional management of pre-dialysis Stage IV CKD. The use of SGA for nutrition assessment and including PG-SGA to measure change is recommended for routine nutrition assessment of pre-dialysis CKD. The provision of individual nutrition counselling with regular follow-up, with a focus on promoting intake provides beneficial patient outcomes supporting optimal nutritional status in pre-dialysis CKD patients.

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ID Code: 16595
Item Type: QUT Thesis (PhD)
Supervisor: Ash, Susan, Bauer, Judith, & Davies, Peter
Keywords: chronic kidney disease, dialysis, nutritional assessment
Department: Faculty of Health
Institution: Queensland University of Technology
Copyright Owner: Copyright Katrina Louise Campbell
Deposited On: 03 Dec 2008 04:06
Last Modified: 28 Oct 2011 19:50

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