MNT: Disorders of Lipid Metabolism (2015)

Citation:

Gaetke LM, Stuart MA, Truszczynska H. A single nutrition counseling session with a registered dietitian improves short-term clinical outcomes for rural Kentucky patients with chronic diseases. J Am Diet Assoc. 2006 Jan; 106(1): 109-112.PMID: 16390674

PubMed ID: 16390674
 
Study Design:
Retrospective Cohort Study
Class:
B - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:

To determine if nutrition counseling from a Registered Dietician (RD) would improve clinical outcome measures of patients with type 2 diabetes and (CVD) on a subsequent physician visit.

Inclusion Criteria:

Subjects must be:

  • Adult patients and selected subjects seen by the same MD between 1991 and 2002 in a rural outpatient office in small eastern Kentucky town
  • Diagnosed with Type 2 diabetes mellitus (DM) or CVD
  • Referred to the same RD by the physician.

 

Exclusion Criteria:

Subjects were excluded if they were:

  • Diagnosed with additional major medical complications
  • Taking lipid-lowering or hypoglycemic agents.
Description of Study Protocol:

Recruitment

No recruitment, this was a medical record review.

Design

Retrospective cohort study

Intervention

  • One-hour individual diet instruction by RD who provided and explained written materials
  • RD met with patient either on the same day or within a three-week period.

Statistical Analysis

  • Baseline characteristics compared between medical nutrition therapy (MNT) group and group not receiving MNT using two sample T-tests or Χ2 tests of association
  • Mean clinical outcomes were compared using two-way repeated measures analysis of variance: 
    • Within subjects at baseline and three months
    • Between subjects (MNT compared to non-MNT)
    • BMI measures using whole sample (N=175)
    • Disease-specific measures done for CVD (N=94) and Type 2 DM (N=94) separately, sample sizes varied due to missing data
  • Post-hoc comparison of means done by comparing change in outcome measures over a three-month (baseline to follow-up) within groups  
  • Mean clinical outcomes adjusted by age and sex.
Data Collection Summary:

Timing of Measurements

  • Clinical and anthropometric measures abstracted from medical records at a baseline MD visit before seeing the RD (if seen) 
  • Second measures collected from chart at a second MD visit three months after scheduled nutrition counseling.

Dependent Variables

  • Clinical outcome measures:
    • Fasting blood glucose
    • HbA1c
    • TC, LDL, HDL, TC/HDL, TG
  • Anthropometric Measures
    • Body weight
    • BMI.

Independent Variables

Single RD patient visit.

Control Variables

  • Age
  • Sex.

 

Description of Actual Data Sample:

Initial N

  • N=175
  • 58 females, 117 males.

Age

  • Mean age: 60 years
  • Age range: 32 to 90 years.

Group Characteristics

  • MNT group was significantly younger than non-MNT group (57.6±12.0 years vs. 63.0±12.4 years, P=0.004)
  • MNT group had a HbA1c significantly higher than non-MNT group (9.8%±2.5% vs. 8.4%±1.7%, P=0.02)
  • MNT group did not differ significantly in gender compared to non-MNT group
  • MNT group were more likely to use tobacco than non-MNT group (38.1% vs. 18.2%, P<0.04).

Location

Small rural eastern Kentucky town.

 

Summary of Results:

 

Variables

Baseline (Adjusted for Age and Sex)

Measures and Confidence Intervals

Three-month Visit (Adjusted for Age and Sex)

Measures and Confidence Intervals

Statistical Significance 

Mean fasting blood glucose (mmol per L)

 

 

 

MNT group

13.4±0.6

8.7±0.4

P<0.001

Non-MNT group

10.9±0.5 13.0±0.4

P<0.001

Mean HbA1c (%)      

MNT group

10.1±0.3 7.2±0.3 P<0.001

Non-MNT group

8.5±0.3 9.6±0.2 P<0.01
Mean TC (mmol per L)      

MNT group

6.6±0.1 6.0±0.1 P<0.001

Non-MNT group

6.4±0.1 6.6±0.1 Not significant, only significant difference seen for unadjusted values
Mean LDL (mmol per L)      

MNT group

4.5±0.2 4.0±0.1 P<0.001
Mean TG (mmol per L)      

MNT group

3.2±3.3 2.0±0.4 P=0.03
Mean TC/HDL      

MNT group

6.7±0.4 6.0±0.3 P=0.03
BMI      

MNT group

30.0±0.8 29.5±0.8 P<0.001
Body weight (lbs)      

MNT group

191.4±4.9 188.6±4.9 P<0.001

 Other Findings

 Variables  MNT Group Non-MNT Group  Significance

Fasting blood glucose

(ADA target, <7.0 mmol per L)

     

Met target at three months

13 (N=44)

0 (N=44) P<0.01

 HbA1c

(ADA target, <7%)

     

Met target at three months

20 (N=44) 0 (N=44) P<0.01

 TC

(NCEP target, <5.17 mmol per L )

     

Met target at three months

8 (N=45) 0 (N=43) P<0.01
  • MNT and non-MNT groups not significantly different at baseline for number of patients meeting targeted guidelines for fasting blood glucose, HbA1c, or TC 
  • A convenience subsample of the study population (MNT group = 43, non-MNT group = 19) was analyzed for length of time outcomes measures remained significantly different from baseline:
    • Outcomes that were significantly different at three months were still significantly different at six months
    • Outcomes that were significantly different at three months had returned to baseline values at 12 months.

 

 

Author Conclusion:
  • Patients with chronic diseases, including type 2 diabetes and CVD, who receive a single nutrition counseling session with an RD had improved clinical outcome measures compared with patients with the same chronic diseases who did not receive nutrition counseling. 
  • Continued need for RD visits after six months based upon small convenience sample of study population
  • Confirms value of nutrition intervention as an effective approach to treating type 2 diabetes and CVD.
Funding Source:
University/Hospital: University of Kentucky Summer Faculty Research Fellowship Program
Reviewer Comments:
  • Body weight is mislabeled in the table. It is defined as kilograms and it should be pounds.
  • No statistical explanation of patients with missing data
  • Provides adjusted measures for age and sex, although gender was not statistically different between groups
  • No control for confounding factors that play a role in disease outcomes, such as tobacco use or ethnicity
  • Unclear as to why statistical comparisons were not made between groups (MNT vs. non-MNT) with continuous clinical outcome data, only with nominal data 
  • No explanation of records not included in final sample size.
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? No
  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? No
  2.4. Were the subjects/patients a representative sample of the relevant population? No
3. Were study groups comparable? No
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) No
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? No
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) No
  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? No
  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")? No
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? No
  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.) No
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? No
  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? No
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? No
  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? N/A
  6.8. In diagnostic study, were details of test administration and replication sufficient? Yes
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? No
  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)? No
  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? No
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