EAL

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

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To assess the effect of MNT provided by dietitians on medical and clinical outcomes for adults with NIDDM, and to compare MNT administered according to basic nutrition care (BC) to that of practice guidelines care (PGC).

Inclusion Criteria:

Diagnosis or treatment for type 2 diabetes mellitus
38 to 76 years of age
Free of serious complications or comorbidities

Exclusion Criteria:

Diabetes complications: gastroparesis, renal disease
Recent heart attacks or strokes
Other acute illnesses, such as cancer or surgery, in the last 4 weeks
Illnesses requiring corticosteroid therapy

Description of Study Protocol:

Recruitment Clinic patients were recruited from clinics in Minneapolis, Florida, and Colorado. 247 subjects were recruited.

Design

Randomized Controlled Clinical Trial. 247 subjects randomly assigned to medical nutrition therapy (MNT): basic care (BC) or practice guidelines nutritional care (PGC).

Intervention

BC: single visit with RD

PGC: initial visit with RD followed by 2 visits during the first 6 wk of the study period.

Blinding Used: none mentioned

Statistical Analysis

Power calculation was done to determine sample size; 68 subjects were needed in each group to detect a 1.0 percentage point difference in the amount of change in HbA1C level between groups. Initial analysis of the discrete variables was done using the chi-square statistic with Yates correction. Initial analysis of continuous variables was done by ANOVA. The changes in variables between time periods were analyzed by paired t test, and comparisons between groups were analyzed using a t test for independent groups.

Data Collection Summary:

Timing of Measurements: Data collected at baseline, 3 and 6 mos.

Dependent Variables

Fasting plasma glucose analyzed by hexokinase method
HbA1c determined by ion exchange HPLC
Serum total cholesterol, LDL cholesterol, HDL cholesterol and triglycerides measured by enzymatic methods
Weight, BMI and waist:hip ratio measured using electric or balance-beam scale
Changes in medical therapy

Independent Variables

PGC or BC

Control Variables

Duration of diabetes
Form of medical treatment
Amount of self-monitoring of blood glucose levels

Description of Actual Data Sample:

Initial N: 247 subjects recruited for the study. 53 from Colorado, 68 from Florida, and 126 from Minnesota.

Attrition (final N): 203 completed the study (dropout rate 18%). Results reported for 179 subjects (72% of initial enrollment) with complete data at all time points.

Age: 38 to 76 years

Ethnicity : 81-92% white

Other relevant demographics: 67%-75% college educated or higher

Anthropometrics: No differences in baseline data for those who stayed in study and those who dropped out.

Location: Study conducted in outpatient diabetes centers in 3 states (Minnesota, Florida, Colorado) from 1992-1993. Control group from primary care physician practices in Minneapolis, MN

Summary of Results:

	PGC - 0 months	PGC - 6 months	BC - 0 months	BC - 6 months
FPG (mmol/L)	10.2	9.1, P < 0.001	9.8	9.2, P < 0.001
HbA1C (%)	8.3	7.4, P < 0.001	8.3	7.6, P < 0.001
LDL-Cholesterol (mmol/L)	3.34	3.25	3.50	3.51
Weight (kg)	93.9	92.4	93.7	92.0

Other Findings:

At 6 months, PGC resulted in significant improvements in blood glucose control as indicated by FPG and HbA1C levels and BC resulted in significant improvements in HbA1C level.

Participants assigned to the PGC group had a mean FPG level at 6 months that was 10.5% lower than the level at entry, and those in the BC group had a 5.3% lower value.

Among subjects who had diabetes longer than 6 months, those who received PGC had a significantly better HbA1C level at 3 months compared with those receiving BC. The comparison group showed no improvement in glycemic control over a comparable 6 months.

PGC subjects had significant improvements in cholesterol values at 6 months, and subjects in both the PGC and BC groups had significant weight loss.

Author Conclusion:

MNT provided by RD resulted in significant improvements in medical and clinical outcomes in both the BC and PGC groups and is beneficial to persons with type 2 diabetes mellitus. Persons with a duration of diabetes longer than 6 months tended to do better with PGC than BC. Because of the upward trend in glucose levels after 3 months, ongoing MNT by the RD is important for long-term metabolic control.

Funding Source:

Not-for-profit

Foundation associated with industry:

Reviewer Comments:

In this study, the PGC group had 3 encounters with an RD over the first 6 weeks of the study whereas the BC group had 1 encounter with an RD during the study period. Those who had diabetes for at least 6 months showed greater improvements in blood glucose than those who were newly diagnosed. This difference is probably because patients who were newly diagnosed had less knowledge and skill for self-management of their diabetes.

The effects of MNT were known by 6 weeks in the PGC group. At that point, the RD must evaluate and act on the outcomes of MNT.

This study demonstrates the need for ongoing diabetes education by the RD to maintain blood glucose goals.

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?	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?	Yes
	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?	Yes
	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?	???
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)?	???
	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?	Yes
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