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


Al-Shookri A, Khor GL, Chan YM, Loke SC, Al-Maskari M. Effectiveness of medical nutrition treatment delivered by dietitians on glycaemic outcomes and lipid profiles of Arab, Omani patients with type 2 diabetes. Diabet Med. 2012; 29(2): 236-244.

PubMed ID: 21824187
Study Design:
Randomized Controlled Trial
A - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:

To investigate the effectiveness of practice guideline nutritional care compared with usual nutrition care on medical and clinical outcomes for patients with type 2 diabetes in Oman.

Inclusion Criteria:
  • Age between 30 years and 70 years
  • Diagnosed with having type 2 diabetes
  • Free of diabetic complications (such as gastroparesis and renal disease)
  • Consented to participate in the study.
Exclusion Criteria:
  • A recent heart attack or stroke (within the previous six months)
  • A serious illness (such as cancer or surgery within the previous four weeks)
  • Illnesses requiring corticosteroid therapy
  • Became pregnant.



Description of Study Protocol:


Two hundred subjects were invited to participate.

  • This number was estimated based on the power calculation to detect a 1.0 percentage point difference in the amount of change in HbA1c levels between the groups
  • A total of 77 subjects were required in each group. To account for sample dropout during the period of the study, 23 subjects (approximately 25%) were added to each group.


Randomized controlled trial.

Blinding Used

Implied with measurements.


  • A total of 200 subjects were assigned randomly to the usual nutrition care group or the group receiving practice guidelines nutritional care
    • Each patient was given a number, which was put in a box
    • By random selection, the first 100 numbers were assigned to the usual nutrition care group.
  • Usual Nutrition Care Group (UNC):
    • Before the first visit (after the referral is made) the dietitian obtains the referral data
    • First visit was approximately one hour:
      • A dietitian discusses the general principles of nutrition management of diabetes, nutrition education and nutrition prescription
      • Summary to referral physical
      • A physical will decide if the patient requires a follow-up visit six months after the first visit.
  • Practice Guidelines Nutritional Care Group (PGC):
    • Initial visit was a minimum of one to 1.5 hours:
      • Assessment: Medical, lifestyle and psychological issues
      • Intervention: Nutrition prescription, education and goal setting.
    • First follow-up visit was a minimum of 30 minutes to 45 minutes (within two weeks of initial visit):
      • Assessment: Progress to stated short-term goals and intervention
      • Intervention: Change in medical nutritional treatment if the goals sited at the initial visit were not achieved; ongoing skills and education.
    • Second follow-up visit was a minimum of 30 minutes to 45 minutes (within two weeks to four weeks of the initial visit):
      • Assessment: Progress to target blood glucose goals
      • Intervention: Make medical nutritional treatment changes; recommend medical therapy changes as needed.
    • Ongoing follow-up visit was at minimum once every six to 12 months:
      • Communication: Long-term goals and plans for ongoing care, such as controlling blood glucose, having a healthy lifestyle and controlling risk factors of long-term complications.
    • Summary to referral source.

Statistical Analysis

  • Continuous variables between the two groups were analyzed by ANOVA
  • The changes in variables between at entry, at three months and at six months in each group were analyzed by paired T-test
  • The level for significance for all tests was P<0.05
  • All of the analyses were carried out using the Statistical Package for Social Sciences, version 15.0 (SPSS Inc, Chicago, IL, USA).
Data Collection Summary:

Timing of Measurements

  • The study was conducted during the period from April 2009 to September 2009. The Muslim fasting month of Ramadan was not included in the study period.
  • All subjects were assessed at the time of enrollment and three and six months later.

Dependent Variables

  • Anthropometric measurements:
    • Weight: Measured with patients wearing light clothing and without shoes, by dietitians using an electric scale or beam-balance scale
    • Height: Measured using a wall measure
    • BMI: Calculated as weight in kilograms divided by height in square meters (kg/m2)
    • Waist circumference: Measured by dietitians using a cloth tape measure with subjects standing in a relaxed position. Subjects were measured at the horizontal level that yielded the minimum measurement.
  • Glucose levels:
    • Were measured after a 12-hour fast at baseline, three months and six months
    • With the patient in a seated position, 30ml of venous blood was drawn from the antecubital vein
    • Assessment was made for:
      • Fasting plasma glucose: By the hexokinase method using Baxter Paramax
      • HbA1c levels: By ion exchange high-performance liquid chromatography on a Bio-Rad Diamat analyzer
  • Lipid profile:
    • Assessment of:
      • Serum total cholesterol
      • LDL-cholesterol
      • HDL-cholesterol
      • Serum triglyceride values.
    • Lipid values were determined by enzymatic methods on the Baxter Paramax
  • Outcomes were considered successful if:
    • Weight loss of 1.5kg to 3.0kg at four weeks to six weeks and a weight loss of 4.5kg to 9kg at six months
    • BMI 25 or less
    • Fasting plasma glucose level of 4.4mmol to 7.8mmol per L or a minimum 20% decrease from entry to six months
    • A HbA1c value of 58 mmol per mol [7.5% or less, with a normal measurement less than 42mmol per mol (6%)]
    • Minimum 20% decrease from initial appointment to six-month appointment
    • Total cholesterol of 5.2mmol per L or less
    • LDL-cholesterol of 3.38mmol per L or less
    • Triglyceride levels of less than 2.26mmol per L.

Independent Variables

  • Practice guidelines for medical nutrition treatment
  • Usual nutrition care.
Description of Actual Data Sample:
  • Initial N: N=200 subjects
  • Attrition (final N): N=170 subjects (85% of the original enrollees).


  UNC Group (N=85) Mean±SD PGC Group (N=85) Mean±SD All (N=170) Mean±SD P
Age (years) 52.0±9.2 49.5±11.3 50.7±10.4 0.122


Described as Arab patients.

Other Relevant Demographics

  UNC Group (N=85) PGC Group (N=85) All (N=170)


N=33 (38.8%) N=38 (44.7%) N=71 (41.8%)


N=52 (61.2%) N=47 (55.3%) N=99 (58.2%)
Diabetes duration

Less than four years

N=10 (11.8%) N=22 (25.9%) N=32 (37.6%)

More than four years

N=75 (88.2%) N=63 (74.1%) N=53 (62.4%)               
Medical nutrition therapy (MNT)

MNT alone

N=11 (13%) N=10 (11.8%) N=21 (12.4%)

MNT and oral agents

N=37 (43.5%) N=45 (52.9%) N=82 (48.2%)

MNT and combination therapy (oral agents and insulin)

N=37 (43.5%) N=30 (35.3%) N=67 (39.4%)

Less than high school

N=50 (58.8%) N=48 (56.5%) N=98 (57.6%)

High school

N=15 (17.6%) N=17 (20%) N=32 (18.8%)


N=20 (23.5%) N=20 (23.5) N=40 (23.5%)


There was no significant difference between groups at baseline.

  UNC group (n=85) Mean±SD PGC group (n=85) Mean±SD All (n=170) Mean±SD p
Weight (kg) 72.2±12.9 73.3±13.6  72.7±13.0 0.586 
Body mass index (kg/m2) 28.4±5.2 27.6±5.3  28.0±5.2  0.313
Waist circumference (cm) 97.9±8.3 97.2±7.5  97.5±7.9  0.554
Fasting plasma glucose (mmol per L) 12.1±3.3 12.4±3.1  12.3±3.2  0.466

(mmol per L)

88 89  89  0.632


10.2±2.4 10.3±1.8  10.3±2.1  
Cholesterol (mmol per L) 5.4±0.9 5.3±1.0  5.4±1.0  0.825
LDL-cholesterol (mmol per L) 3.46±0.88 3.57±0.93  3.52±0.90  0.437
HDL-cholesterol (mmol per L) 1.08±0.22 1.05±0.23  1.07±0.23  0.345
Triglycerides (mmol per L) 1.80±0.87 1.64±0.70  1.72±0.79  0.187
Urea (mmol per L) 5.3±1.4 5.6±1.2  5.5±1.3  0.084
Creatinine (mcgmol per L) 62.8±17.0 62.4±12.8  62.6±15.0  0.839
White blood cells (109 per L) 6.2±2.1 6.0±1.5  6.1±1.8  0.459
Hemoglobin (g per dL) 12.5±0.86 12.3±1.4  12.4±1.1  0.224
Platelets (109 per L) 280±68 291±61  286±65  0.309


Muscat, Oman.

Summary of Results:

Key Findings


  PGC (N=85) UNC (N=85)


Entry Mean±SD

Three Months Mean±SD

Six Months Mean±SD

Entry Mean±SD Three Months Mean±SD Six Months Mean±SD

Weight (kg)



Zero vs. three months*


Zero vs. six months*

72.2±12.9 69.7±12.2 69.6±12.1
BMI (kg/m2) 27.6±5.3


Zero vs. three months*

26.2±5.3 28.4±5.2 27.4±4.9 27.4±5.0

Waist circumference (cm)



96.9±7.9 ¥

97.9±8.3 99.0±8.7 100.0±8.7

Fasting plasma glucose (mmol per L)



Zero vs. three months*** 


Zero vs. six months** 

12.1±3.3 11.2±3.0 11.9±3.2

mmol per mol

89 75 80 88 79 84




Zero vs. three months***


Zero vs. six months**

Three vs. six months*

10.2±2.4 9.4±2.0 9.8±1.8
Cholesterol (mmol per L) 5.3±1.0 5.1±1.0 5.1±0.97 5.4±0.9


Zero vs. three months*


Three vs. six months**

LDL-cholesterol (mmol per L) 3.57±0.93 3.74±1.01 3.58±0.98 3.37±0.88 3.63±0.75 3.66±0.87
HDL-cholesterol (mmol per L) 1.05±0.23 1.01±0.33 1.09±0.32 1.08±0.22 1.05±0.25


Zero vs. six months*

Triglycerides (mmol per L) 1.64±0.70


Zero vs. three months*


Zero vs. six months*

1.80±0.87 1.70±0.75


Three vs. six months*

  •  *P<0.05
  • **P<0.01
  • ***P<0.001
  • § P=Significant difference between two groups at three-month point
  • ¥ P=Significant difference between two groups at six-month point
PGC Group Findings
  • Compared with entry time, the mean weight values of the PGC group decreased significantly at the three-month point of the study and these levels were sustained at six months
  • At six months, 55.3% (N=47) of the group receiving PGC had achieved the target outcome of 4.5kg or more weight loss
  • At three months, participants of PGC had reduced their entry fasting plasma glucose mean levels by 16.7% and their HbA1c mean levels by 13.1%
  • At six months, those in the PGC group had reduced their mean fasting plasma glucose level by 11.2% and their HbA1c level by 8.2% compared with levels at entry to the study
  • The waist circumference measurements of the group of patients receiving PGC show a significant decrease compared with patients in the UNC group at the six-month point.

UNC Group

  • At 6 months, 14% (N=12) of the UNC group had achieved a successful weight loss of 4.5kg or more
  • The UNC group showed an insignificant decrease at three months and then an upward trend at six months for both HbA1c and fasting plasma glucose
  • The UNC group demonstrated a mean 7.3% reduction in fasting plasma glucose level and an 8% reduction of HbA1c level at the three-month point.

Both Groups

Approximately 57% (N=97) of all participants (N=170) achieved their target goal of a fasting plasma glucose level of 7.8mmol or less per L and a HbA1c values of 58mmol or less per mol (7.5%) or a 20% decrease after six months. 

Other Findings

  •  By the end of the six-month point:
    • A total of 18.2% (N=31) of the total study group were treated by medical nutritional treatment alone [compared to 12.4% (N=21) at baseline]
    • A total of 47.1% (N=80) were treated by medical nutritional treatment and oral agent [compared to 48.2% (N=82) at baseline]
    • A total of 34.7% (N=59) by medical nutritional treatment with a combination therapy of insulin and oral agents [compared to 39.4% (N=67) at baseline].
  • The group treated with medical nutritional treatment alone and the group treated with medical nutritional treatment and oral hypoglycemic agents experienced a greater weight loss than the other therapy groups (from baseline weight of 73.4±13.8kg to 68.2±13.2kg at six months)
  • The group receiving medical nutritional treatment and a combination therapy of insulin and oral agents also experienced a weight loss from baseline (73.1±13.5kg to 68.4±14.5kg) at six months
  • In the total group (N=170), 20 changes in therapy (12% subjects) were reported:
    • N=6 (7%) in the UNC group
    • N=14 (16.5%) in the PCG group (all recommended by the dietitian to the treating physician for implementation).





Author Conclusion:
  • Medical nutrition therapy provided by dietitians to Arab patients with type 2 diabetes in Oman resulted in significant improvements in anthropometric and biochemical outcomes in both the UNC group and the PCG group
  • Subjects with type 2 diabetes tended to do better with PGC than UNC
  • Ongoing medical counseling in nutrition by a trained dietitian is important for better long-term metabolic control.
Funding Source:
Other: not described
Reviewer Comments:
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? 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? N/A
  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? N/A
  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? No
  10.2. Was the study free from apparent conflict of interest? Yes