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

Citation:

Laurenzi A, Bolla AM, Panigoni G, Doria V, Uccellatore AC, Peretti E, Saibene A, Galimberti G, Bosi E, Scavini M. Effects of carbohydrate counting on glucose control and quality of life over 24 weeks in adult patients with type 1 diabetes on continuous subcutaneous insulin infusion. Diabetes Care. 2011; 34: 823-827.

PubMed ID: 21378215
 
Study Design:
Randomized Controlled Trial
Class:
A - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:

To test the effect of carbohydrate counting on glycemic control and quality of life in adult patients with type 1 diabetes who are receiving continuous subcutaneous insulin infusion (CSII).

Inclusion Criteria:
  • Provided written informed consent
  • Type 1 diabetes
  • Treated with CSII for more than three months
  • Between the ages of 18 and 65 years.

 

Exclusion Criteria:
  • Serum creatinine higher than 124umol per L in women and higher than 150umol per L in men
  • Previous training in carbohydrate counting
  • Celiac disease, pregnancy, severe co-morbidities
  • Any disability preventing compliance with study procedures.
Description of Study Protocol:

Recruitment

Patients who followed CSII and attended the outpatient clinic of the San Raffaele Scientific Institute in Milan were recruited for the study.

Design

Randomized control trial. 

Blinding Used  

Implied with measurements.

Intervention

  • Patients in the intervention group were trained on carbohydrate counting and bolus calculation in the first 12 weeks using the I:CHO and sensitivity factor during four to five individual sessions with the dietitian and a diabetologist
  • Patients in the control group continued estimating their pre-meal insulin dose in the usual empirical way.
Statistical Analysis
  • Intention to treat (ITT) analysis included all randomized patients who concluded the trial, i.e., 56 patients (28 per group)
  • The per-protocol analysis included 20 patients in the carbohydrate counting group and 27 patients in the control group
  • Baseline characteristics of study participants in the two groups were compared using the X2 test, unpaired two-tailed T-test or Mann-Whitney two-sample statistic as appropriate
  • Changes from baseline of DSQOLS scores, BMI and waist circumference, total daily insulin dose, fasting plasma glucose, LBGI and HBGI in the two groups were compared using the unpaired, two-tailed T-test
  • Mixed effects models were used to analyze hypoglycemic events during the study.
Data Collection Summary:

Timing of Measurements

Measurements made at baseline and after 24 weeks.

Dependent Variables

  • Glycemic control was assessed through change in HbA1c and fasting plasma glucose. HbA1c was measured using ion-exchange high-performance liquid chromatography with a normal range of 3.5% to 6.0%.
  • BMI and waist circumference were measured
  • Total daily insulin dose was recorded and patients were asked to complete a validated instrument for assessing diabetes-specific quality of life (DSQOLS)
  • Capillary glucose measurements were downloaded from the memory of glucose meters at 12 weeks and 24 weeks at the time of the outpatient visits; LBGI and HBGI were calculated as reported.
Independent Variables
  • Patients in the intervention group were trained on carbohydrate counting and bolus calculation in the first 12 weeks using the I:CHO and sensitivity factor during four to five individual sessions with the dietitian and a diabetologist
  • Patients in the control group continued estimating their pre-meal insulin dose in the usual empirical way.
Description of Actual Data Sample:
  • Initial N: A total of 67 subjects were assessed for eligibility; 61 were randomized for the study
  • Attrition (final N): A total of 56 completed (28 in the CHO counting group, 28 in the control group)
  • Age: Mean age in the CHO group 41.2±10 years; mean age in the control group 39.8±9.8 years
  • Other relevant demographics: Duration of diabetes in the CHO group was 21.9±11 years and 19.8±11.7 years in the control group
  • Anthropometrics: Mean BMI (kg/m2) in the CHO group was 23.7 and 23.8 in the control group. The two groups were similar in:
    • Age
    • Sex
    • Years of school completed
    • Duration of diabetes
    • Duration of CSII
    • Type of insulin used
    • Daily insulin requirement
    • HbA1c levels. 
  • Location: Milan, Italy.
Summary of Results:

Key Findings

  • Intention to treat analysis showed improvement of the DSQOLS score related to diet restrictions (week 24–baseline difference, P=0.008) and reduction of BMI (P=0.003) and waist circumference (P=0.002) in the intervention group compared with control subjects
  • No changes observed in:
    • HbA1c
    • Fasting plasma glucose
    • Daily insulin dose
    • Hypoglycemic episodes (less than 2.8mmol per L).
  • Per protocol analysis, including only patients who continuously used carbohydrate counting and CSII during the study confirmed improvement of the DSQOLS score and reduction of BMI and waist circumference, and showed a significant reduction of HbA1c (-0.35% vs. control subjects, P=0.05).
Author Conclusion:

Among adult patients with type 1 diabetes treated with CSII, carbohydrate counting is safe and improves quality of life, reduces BMI and waist circumference and, in per protocol analysis, reduces HbA1c.

Funding Source:
Industry:
GlaxoSmithKline
Pharmaceutical/Dietary Supplement Company:
Reviewer Comments:

Strengths

  • The sample size is at least as large as that of previous research involving patients with type 1 diabetes who receive multiple daily injections
  • Patients were provided training in carbohydrate counting that is feasible in the setting of a diabetes clinic.
Weaknesses
  • Relatively small numbers of subjects in groups
  • Patients in the intervention group had more contact with the diabetes care team during the teaching of carbohydrate counting, thus preventing ruling out that the intervention group lost weight and improved metabolic control secondary to the extra attention rather than the use of carbohydrate counting.
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? 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? ???
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? 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? 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? 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)? Yes
  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? 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