MNT: RDN in Medical Team (2015)

Orazio LK, Isbel NM, Armstrong KA, Tarnarskyj J, Johnson DW, Hale RE, Kaisar M, Banks MD, Hickman IJ. Evaluation of dietetic advice for modification of cardiovascular disease risk factors in renal transplant recipients. J Ren Nutr. 2011; 21 (6): 462-474. PubMed ID: 21454091
Study Design:
Randomized Controlled Trial
A - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:
  • The aim of this study was to evaluate the effect of increased dietary advice in a multi-disciplinary lifestyle intervention comparing aggressive risk-factor modification for cardiovascular disease (CVD) with standard post-transplant care in renal transplant recipients (RTR) with abnormal glucose tolerance (AGT).
  • The secondary aims were to determine whether increased dietary advice was associated with improvement of healthy eating habits and increased weight loss that was associated with improvement in cardiovascular risk factors.
Inclusion Criteria:
  • Adult RTRs with AGT
  • More than six months post-transplant.
Exclusion Criteria:
Not described.
Description of Study Protocol:


  • Participants were recruited from the renal transplant population at the Princess Alexandra Hospital Renal Unit
  • Additional recruitment measures previously published.


  • RTR with AGT were randomized to a lifestyle intervention that consisted of either regular consultations with the dietitian and multi-disciplinary team or standard care
  • Detailed description of study design previously published.


Dietary advice
  • Participants received individualized dietary advice for the duration of the trial
  • The primary goal of nutrition therapy was achievement or maintenance of a healthy weight using a Mediterranean-style (less than 30% total energy from fat), low glycemic index diet
  • A deficit of 500kcal per day was used to promote 0.5kg of weight loss per week.

Physical activity advice

  • Physical activity (PA) goals were individualized for each patient according to mobility, fitness, personal preference and self-efficacy, with the long-term goal to achieve 150 minutes of accumulated physical activity per week
  • The Transtheoretical Model of Health Behavior Change or Stage of Change Model was a component of the lifestyle intervention, providing a framework for goal-setting throughout the trial.

Statistical Analysis

  • An intent-to-treat approach was used in the assessment of anthropometry, biochemistry, blood pressure, PA and cardiorespiratory fitness (CF). Patients with missing data or who dropped out before two years in the analysis had data carried forward.
  • Unpaired T-tests were used to compare differences in patient demographics, anthropometry, biochemistry, cardiovascular risk factors, medications and dietary intake at baseline and percentage change in weight and CF between the intervention and control groups
  • Unpaired T-tests were used to examine differences in dietary intake between the Intervention and Control Groups at 12- and 24-month follow-up periods
  • Chi-squared tests were used for categorical data to compare differences between the Intervention and Control Groups for anthropometry, biochemistry, cardiovascular risk factors, blood pressure, and medications and dietary intake at baseline and after two years
  • A two-way repeated measures analysis of variance (ANOVA) was conducted to assess the effect of the intervention on anthropometry, biochemistry, blood pressure and PA over the five time-points: Baseline, six months, 12 months, 18 months and 24 months
  • Multiple comparisons in analysis of variance were performed with Bonferroni adjustments
  • Univariate logistic regression analysis was carried out to investigate biochemical and clinical parameters associated with more than a 5% decrease in body weight
  • Standard regression diagnostic techniques, including checkup of the model, were carried out
  • Statistical significance was considered at P<0.05 a priori. 
Data Collection Summary:

Timing of Measurements

  • Anthropometrics, biochemistry, blood pressure and physical activity were measured at baseline and at the six-month, 12-month, 18-month and 24-month follow-ups
  • Dietary intake was evaluated at baseline and at the 12-month and 24-month follow-ups.

Dependent Variables

  • Anthropometry: Body weight, BMI, waist circumference, hip circumference and waist-to-hip ratio were measured using standard methods
  • Biochemical factors: Glucose, glycosylated hemoglobin, total cholesterol, HDL-cholesterol, LDL-cholesterol, VLDL and triglycerides were measured from blood samples collected using standard venipuncture after an eight-hour overnight fast
  • Clinical factors: Medications were noted; blood pressure was measured using a standard sphygmomanometer
  • Dietary intake: A seven-day estimated food record was completed. Three random days from the seven-day record were used for analysis: Two weekdays and one weekend day.
  • Physical activity levels: Assessed using a simplified version of the Physical Activity Statewide Questionnaire
  • Cardiorespiratory fitness: Assessed by measuring oxygen uptake (VO2) by breath-by-breath analysis of expired gas during standard treadmill exercise. Peak VO2 was defined as the greatest value of three 20-second averages during exercise. Equations were used to predict peak VO2 according to weight, height and gender, and adjusted for age.

Independent Variables

Regular consultations with a dietitian and multi-disciplinary team, including dietary and physical activity advice.

Control Variables

  • All patients were counseled about smoking cessation
  • Aspirin was prescribed to all patients, unless contraindicated.
Description of Actual Data Sample:
Initial N
  • 102 (62 male, 40 female)
  • Intervention Group: 56 (33 male, 23 female)
  • Control Group: 46 (29 male, 17 female).
Attrition (Final N)

73 patients completed two years of the study (71.6%).


  • Intervention Group: 4.9±9.9 years
  • Control Group: 54.7±11.8 years.


Not described.


There were no differences between the groups at baseline with regard to demographics, CVD risk factors, anthropometry, biochemistry or medications.


Brisbane, Australia.

Summary of Results:

Key Findings


  • Total fat intake rates were significantly lower in the Intervention Group as compared with the Control Group at the 24-month follow-up (54g vs. 65g, P=0.01)
  • Percentage saturated fat intake rates were significantly lower in the Intervention Group as compared with the Control Group at 24-month follow-up (10% vs. 13%, P=0.05)
  • There was a trend for overweight (but not obese) patients to lose a larger percentage of weight as compared with those in the Control Group (-3.95±5.44% vs. 0.11±7.67%, P=0.059)
  • Overall, RTR were significantly less fit than age-and gender-matched controls; mean peak oxygen uptake was 19.42±7.09ml per kg per minute vs. 28.35±8.80ml per kg per minute, P=0.000
  • Simple exercise advice was not associated with any improvement in total PA or CF in either group at the 24-month follow-up
  • There was no significant difference from baseline until follow-up for either group in weight, waist circumference and waist-to-hip ratio.

Biochemical and clinical factors

  • At the 24-month follow-up, significantly more patients in the Intervention Group were on thiazolidinedione (TZD) than those in the Control Group: 25% vs. 0%, P<0.001
  • More patients in the Intervention Group were on a statin than those in the Control Group: 96% vs. 80%, P=0.021
  • More patients in the Intervention Group met the target for LDL (less than two mmol per L) than in the Control Group, 61% vs. 26%, P=0.001.

Dietary intake

At the 12- and 24-month follow-up periods, energy intake, total fat intake and percentage saturated fat intake were significantly lower in the Intervention Group compared with that in the Control Group (energy, 7,096kJ vs. 8,095kJ, P=0.031 and 6,337kJ vs. 7,630kJ, P=0.021; total fat, 57g vs. 65g, P=0.040 and 54g vs. 65g, P=0.010; percentage saturated fat, 10% vs. 13%, P=0.011 and 10% vs. 13%, P=0.050).

Physical activity and cardiovascular fitness

  • There was no significant change in PA over time for the Intervention Group
  • There was no significant difference in ability to meet PA guidelines targets between the Intervention and Control Groups
  • There was no significant difference in the percentage change in peak VO2 between the Intervention and Control Groups.
Author Conclusion:
  • Dietary advice can contribute to healthier eating habits and a trend for weight loss in RTR with AGT. These improvements in conjuction with multi-disciplinary care and pharmacological treatment can lead to improvements in cardiovascular risk factors such as lipid profile.
  • Simple advice to increase PA was not effective in improving CF and other measures are needed.
Funding Source:
Queensland Health and the Princess Alexandra Hospital Foundation
Reviewer Comments:
  • The Study Design and Study Population section of the article states that a "Detailed description of study design has been published previously..." and refers the reader to another article for a description of recruitment methods and standard and intervention group designs. This article was unavailable.
  • Noted a discrepancy regarding number of participants. Table One shows 102 participants started study, however the article reports 73 participants completed the study and 28 participants withdrew (73+28=101).
Quality Criteria Checklist: Primary Research
Relevance Questions
  1. Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies) Yes
  2. Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? Yes
  3. Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice? Yes
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) Yes
Validity Questions
1. Was the research question clearly stated? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? Yes
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.3. Were the target population and setting specified? Yes
2. Was the selection of study subjects/patients free from bias? Yes
  2.1. Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study? Yes
  2.2. Were criteria applied equally to all study groups? Yes
  2.3. Were health, demographics, and other characteristics of subjects described? Yes
  2.4. Were the subjects/patients a representative sample of the relevant population? Yes
3. Were study groups comparable? Yes
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) Yes
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? Yes
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) Yes
  3.4. If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis? N/A
  3.5. If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.) N/A
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? N/A
4. Was method of handling withdrawals described? Yes
  4.1. Were follow-up methods described and the same for all groups? Yes
  4.2. Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.) Yes
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? Yes
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? Yes
5. Was blinding used to prevent introduction of bias? Yes
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? Yes
  5.2. Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.) Yes
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? N/A
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? N/A
  5.5. In diagnostic study, were test results blinded to patient history and other test results? N/A
6. Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? No
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? No
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? N/A
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? Yes
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? ???
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? No
  6.6. Were extra or unplanned treatments described? N/A
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? N/A
  6.8. In diagnostic study, were details of test administration and replication sufficient? N/A
7. Were outcomes clearly defined and the measurements valid and reliable? Yes
  7.1. Were primary and secondary endpoints described and relevant to the question? Yes
  7.2. Were nutrition measures appropriate to question and outcomes of concern? Yes
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? Yes
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? Yes
  7.5. Was the measurement of effect at an appropriate level of precision? Yes
  7.6. Were other factors accounted for (measured) that could affect outcomes? Yes
  7.7. Were the measurements conducted consistently across groups? Yes
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? Yes
  8.1. Were statistical analyses adequately described and the results reported appropriately? Yes
  8.2. Were correct statistical tests used and assumptions of test not violated? Yes
  8.3. Were statistics reported with levels of significance and/or confidence intervals? Yes
  8.4. Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)? Yes
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? Yes
  8.6. Was clinical significance as well as statistical significance reported? Yes
  8.7. If negative findings, was a power calculation reported to address type 2 error? N/A
9. Are conclusions supported by results with biases and limitations taken into consideration? Yes
  9.1. Is there a discussion of findings? Yes
  9.2. Are biases and study limitations identified and discussed? Yes
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.2. Was the study free from apparent conflict of interest? Yes