MNT: Disorders of Lipid Metabolism (2015)
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.
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.
Subjects were excluded if they were:
- Diagnosed with additional major medical complications
- Taking lipid-lowering or hypoglycemic agents.
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.
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.
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.
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.
- 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.
University/Hospital: | University of Kentucky Summer Faculty Research Fellowship Program |
- 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
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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 | |