DM: MNT (2007)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
To examine if nutrition counseling from an RD would improve clinical outcome measures of patients with type 2 diabetes and CVD on a subsequent visit to their physician.
Inclusion Criteria:
  • seen by the physician between 1991 and 2002
  • were adult patients diagnosed with type 2 diabetes or CVD
  • were free of major medical complications
  • had been referred to the same RD by the physician
  • were not on lipid-lowering or hypoglycemic agents
Exclusion Criteria:
Not specified
Description of Study Protocol:

Recruitment - 500 medical charts of patients and selected subjects were reviewed. 175 met criteria and were selected. 

Design -  Retrospective analysis of records were examined to determine changes in clinical and anthropometric measures at a baseline physician's visit before seeing an RD and a second physician visit 3 months after the scheduled nutrition counseling session. A detailed assessment form was used by the RD, who also provided individualized dietary instruction lasting approximately one hour, provided and explained printed materials, and met with patients on the same day or within three weeks of the initial physician visit.

Blinding used (if applicable) - not applicable

Intervention (if applicable) - single nutrition counseling session

Statistical Analysis - Descriptive statistics were used to summarize demographic and baseline information. Baseline characterics between the two groups were compared using two-sample t test or X2 tests of association. Mean clinical outcome measures were compared using two-way repeated measures analysis of variance with time as the within subject factor (baseline, 3 months) and groups (with and without MNT) as a between-subjects factor. Because the groups differed by age and sex, these were used as control variables in the analysis. Because there were missing data, the actual sample sizes used in comparing nutrition counseling groups differed across outome measures.

 

Data Collection Summary:

Timing of Measurements - baseline, 3 months

 Dependent Variables

  • HbA1c, fasting plamsa glucose
  • lipids: total cholesterol, LDL cholesterol, HDL cholesterol; triglycerides, ratio of total cholesterol to HDL
  • BMI, body weight

Independent Variables

  • with or without a single MNT counseling session by the same RD

 Control Variables -

  • age
  • sex

 

Description of Actual Data Sample:

Initial N: 175 patients were included in the study, data was missing for some. 58 men, 117 women.

Attrition (final N): 175

Age: average age was 60 years - range 32 to 90

Ethnicity: not specified

Other relevant demographics:  81 had CVD, 81 had diabetes, 13 had both (included in both samples)

Anthropometrics not specified

Location: small town, eastern Kentucky

 

Summary of Results:

Other Findings

The two groups were significantly different in mean age (MNT 57.6 ± 12.0 years; non-MNT 63.0 ± 12.4 years). They did not differ significantly according to sex, although there were more women than men.

  • Among the MNT group, mean fasting blood glucose and mean HbA1c decreased significantly from baseline to 3 months.
  • In the non-MNT group, both increased significantly by 3 months.
  •  Among the MNT group, mean total cholesterol level, mean LDL level, mean triglyceride level, and mean ratio of total cholesterol to HDL levels decreased significantly from baseline to 3 months.
  • In the non-MNT group, mean total cholesterol increased significantly from baseline to 3 months, and there was a statistically insignificant increase in mean LDL level, triglyceride level, and the ratio of cholesterol to HDL, and no change in HDL level.

Using the American Diabetes Association target ranges for fasting glucose and HbA1c, and the National Cholesterol Education Program target ranges for total cholseterol:

  • a significant number of the MNT group improved their fasting blood gluose score (from 1 out of 44 at baseline being in normal limits to 13 out of 44) after 3 months.
  • a significant number of the MNT group improved their HbA1c  (from 3 out of 44 in normal range to 20 out of 44) after 3 months.
  • a significant number of the MNT group improved their  total cholesterol (from 1 out of 45 in normal limits to 8 out of 45) after 3 months.
  • In the non-MNT group, the number of patients within normal limits decreased for all three measures.
  • The X2 indicated a statistically significant difference between the groups after 3 months (P<.01 for all three measures), whereas the difference at baseline was not statistically significant.

 The effect of a single nutrition couseling session lasted at least 3 months.

Author Conclusion:
Patients with chronic diseases, including type 2 diabetes and CVD, who received a single nutrition counseling session from an outreach RD, had improved clinical outcome measures compared with patients with the same chronic diseases who did not receive nutrition counseling.
Funding Source:
Reviewer Comments:
Good discussion of issues of retrospective studies and implications for this one in particular. Excellent table showing all the specific numbers for each outcome value, and calculations, which is too large to include here. The choice of a single MNT session was interesting.
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? ???
  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? ???
  2.2. Were criteria applied equally to all study groups? Yes
  2.3. Were health, demographics, and other characteristics of subjects described? ???
  2.4. Were the subjects/patients a representative sample of the relevant population? ???
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.) N/A
  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? Yes
  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? N/A
  4.1. Were follow-up methods described and the same for all groups? N/A
  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%.) N/A
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? N/A
  4.4. Were reasons for withdrawals similar across groups? N/A
  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? N/A
  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.) N/A
  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? N/A
  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? No
  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? No
  10.2. Was the study free from apparent conflict of interest? Yes