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DM: Effectiveness of MNT Provided by RD/RDN (2015)

Citation:

Coppell KJ, Kataoka M, Williams SM, Chisholm AW, Vorgers SM, Mann JI. Nutritional intervention in patients with type 2 diabetes who are hyperglycaemic despite optimized drug treatment: Lifestyle Over and Above Drugs in Diabetes (LOADD) study: randomized controlled trial. BMJ. 2010; 341: c3337.

PubMed ID: 20647285
 
Study Design:
Randomized Controlled Trial
Class:
A - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:

To investigate the extent to which intensive evidence-based dietary advice is able to influence glycemic control and risk factors for cardiovascular disease in people with type 2 diabetes who had persistent hyperglycemia and remained at high cardiovascular risk despite their drug treatment having been optimized according to current guidelines. 

Inclusion Criteria:
  • Younger than 70 years of age
  • Resident of Dunedin, New Zealand
  • Diagnosed with type 2 diabetes for at least nine months before study entry
  • HbA1c over 7% despite standard dietary advice by an RD, MD or RN, together with oral hypoglycemic agents, insulin or both
  • Two or more of the following:
    • BMI at least 25
    • Hypertension (HTN) treated with medication or blood pressure (BP) above 140/90mmHg despite optimized antihypertensive drug treatment
    • Dyslipidemia (taking lipid-modifying drugs or one one or more of total cholesterol (TC) over 5.2mmol per L, low density lipoprotein cholesterol (LDL-C) over 3.5mmol per L, triglycerides (TG) over 2.0mmol per L and high density lipoprotein cholesterol (HDL-C) over 1.0mmol per L despite optimized lipid modifying drug treatment.
Exclusion Criteria:
  • Pregnancy
  • Serious chronic illness other than diabetes considered likely to need a start or change of drug treatment
  • Unwillingness to attempt to comply with intensive dietary advice if randomized to intervention. 
Description of Study Protocol:
  • Recruitment: Local general practices, hospital diabetes clinics, regional diabetes retinal screening service, pharmacies, local diabetes society and advertising local weekly newspaper
  • Design: RCT
  • Blinding used (if applicable): Implied with measurements.

Intervention

  • Both groups received advice on physical activity of achieving at least 30 minutes of physical activity of moderate intensity on most, if not all, days of the week
  • Both groups continued to attend their usual provider of clinical care for diabetes (general practitioner or hospital diabetes clinic)
  • The Intervention Group consumed a diet of 10% to 20% protein, less than 30% fat, less than 10% SFA or less than 8% if LDL-C was elevated, less than 10% PUFA and 45% to 60% CHO of total energy; dietary fiber, 40g per day or 20g per 1,000kcal, with half as soluble fiber. Overweight and obese subjects were asked to achieve a 5% weight loss. Each participant was given examples of foods, recipes and meals on the basis of the initial three-day weighed food record, personal preferences, budget and socio-cultural factors with emphasis on food quantities, vegetables, fruit, legumes, whole grains, fish, nuts, low-fat dairy products and appropriate fats and oils. Meat was to be lean.
  • In the Intervention Group, each participant had two individual sessions with the study dietitian within the first month after randomization, then monthly sessions for five months. There was one group education session within the first two months and a telephone call between visits, as deemed necessary by the dietitian. Participant families were encouraged to attend dietary education sessions.  The three-month measurements provided a means of offering feedback on progress and further support.
  • The Control Group was given an undertaking that they would receive further advice depending on the outcome of the trial and they had no further contact with the researchers until reassessment at the end of the six-month trial.

Statistical Analysis

  • Analysis of covariance with adjustment for sex, age and baseline measure, to compare the differences between the treatments at six months was used
  • Two-sided significance tests throughout were used
  • Results were presented as differences between the two groups and no adjustment was made for multiple testing
  • A modified intention to treat principle, using a pre-established analysis plan, was used to analyze the data.
Data Collection Summary:

Timing of Measurements

Baseline and six months, plus at three months for the Intervention Group.

Dependent Variables

  • HbA1c: After overnight fast on two separate occasions with one week; averaged
  • Hypoglycemic drugs
  • Weight and BMI: In duplicate by research RN
  • Waist circumference (WC): In duplicate by research RN
  • Blood pressure (BP): In triplicate by research RN
  • Fasting blood glucose (FBG) and lipid profile: After overnight fast on two separate occasions with one week; averaged
  • Urinary creatinine: Jaffe reaction method
  • Urinary albumin: Inhalant immuno-turbidimetric assay
  • Diet adherence: Three-day weighed food record on two weekdays and one weekend day; instructions given by a dietitian.

Independent Variables

  • The Intervention Group consumed a diet of 10% to 20% protein, less than 30% fat, less than 10% SFA or less than 8% if LDL-C was elevated, less than 10% PUFA and 45% to 60% CHO of total energy; dietary fiber, 40g per day or 20g per 1,000kcal, with half as soluble fiber. Overweight and obese subjects were asked to achieve a 5% weight loss. Each participant was given examples of foods, recipes and meals on the basis of the initial three-day weighed food record, personal preferences, budget and socio-cultural factors with emphasis on food quantities, vegetables, fruit, legumes, whole grains, fish, nuts, low-fat dairy products and appropriate fats and oils. Meat was to be lean.
  • In the Intervention Group, each participant had two individual sessions with the study dietitian within the first month after randomization, then monthly sessions for five months. There was one group education session within the first two months and a telephone call between visits, as deemed necessary by the dietitian. Participant families were encouraged to attend dietary education sessions. The three-month measurements provided a means of offering feedback on progress and further support.
  • The Control Group was given an undertaking that they would receive further advice depending on the outcome of the trial and they had no further contact with the researchers until reassessment at the end of the six-month trial. 

Control Variables

  • Both groups received advice on physical activity of achieving at least 30 minutes of physical activity of moderate intensity on most (if not all) days of the week
  • Both groups continued to attend their usual provider of clinical care for diabetes (general practitioner or hospital diabetes clinic).
Description of Actual Data Sample:
  • Initial N: 104 randomized; 52 in each group
  • Attrition (final N): 94 (55 women); 46 in the Intervention Group and 48 in the Control Group
  • Age: 56.6±8.8 years for the Intervention Group and 58.4±8.8 years for the Control Group
  • Ethnicity:  New Zealanders of European descent with 25% of Mori, Pacific Island, Lebanese or Indian ethnicity
  • Other relevant demographics: Smoking status, duration of diabetes and use of hypoglycemic drugs were similar
  • Anthropometrics: No differences reported
  • Location: New Zealand.
Summary of Results:

Key Findings

  • Improvements occurred in most clinical and lab measures in the Intervention Group with minimal changes in the Control Group
  • The difference in HbA1c between the two groups (-0.4%, 95% confidence interval, -0.7% to -0.1%) at the end of the six months after adjustment for baseline values, age and sex, was highly significant (P=0.007)
  • Differences in change of weight, BMI and WC were statistically significant in the Intervention Group (-1.3kg, -2.4kg to -0.1kg; P=0.032), body mass index (-0.5, -0.9 to -0.1; P=0.026) and waist circumference (-1.6cm, -2.7cm to -0.5cm; P=0.005), respectively
  • There were no significant differences between groups in terms of glucose levels
  • There were no significant differences between groups in terms of total cholesterol, HDL-cholesterol, LDL-cholesterol, triglycerides or blood pressure
  • Nearly one-third of the controls (N=14; 29%) had doses of hypoglycemic drugs increased vs. four (9%) in the Intervention Group. Six (13%) in the intervention and two (4%) of the controls had decreases in the hypoglycemic drugs. Four of the 14 patients on insulin had their insulin doses decreased by up to 81 units. No serious adverse events were reported. 
  • Food records were available for 78 of the patients at both baseline and six months. A decrease in saturated fat (-1.9% total energy, -3.3% to -0.6%; P=0.006) and an increase in protein (1.6% total energy, 0.04% to 3.1%; P=0.045) in the Intervention Group were the most striking differences in nutritional intake between the two groups.
  • The Intervention Group had a greater intake of low-fat dairy products (8% vs. 6% of total energy) and nuts (5% vs. 1% total of energy) than the controls. In the controls, 7% of total energy was from high-fat dairy products vs. 3% in the Intervention Group. 
Author Conclusion:

Intensive dietary advice has the potential to appreciably improve glycemic control and anthropometric measures in patients with type 2 diabetes and unsatisfactory HbA1c despite optimized hypoglycemic drug treatment. 

Funding Source:
Government: Health Research Council of New Zealand and Southern Trust, New Zealand
Reviewer Comments:

Text reported a final N of 94, while the table indicated 93.

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? ???
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? N/A
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? No
  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? Yes
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? Yes
  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? Yes
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? Yes
  6.6. Were extra or unplanned treatments described? No
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? Yes
  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)? N/A
  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