DM: Prevention of Type 2 Diabetes (2007)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
  • To assess the nature and extent of interventional therapies regarding prevention of type 2 diabetes.
Inclusion Criteria:
  • To be included in the study, subjects had to have fasting plasma glucose <110 mg/dl and 2 hour (after consuming 75 grams oral glucose) plasma glucose between 110 and 200 mg/dl (Impaired Glucose Tolerance/ IGT)
Exclusion Criteria:
  • Not discussed
Description of Study Protocol:

Recruitment

  • Initial search for subjects included those who had body mass index >25 kg/m2, family history of diabetes, history of gestational diabetes, dyslipidemia, hypertension

Design

  •  Randomized controlled trial

Blinding used (if applicable)

  • It was not described if the medication was blinded or not 

Intervention (if applicable)

  • Subjects were randomized at the 3 month visit:  if they presented at the 3 month visit with their plasma glucose in the range of IGT, they were randomized to one of three medication therapies; if they had normal "postglucose blood sugar", they were maintained with diet and exercise only. 
  • Four study groups were:  intensive lifestyle intervention group, metformin group (500 mg daily) , rosiglitazone  group (2 mg daily), and acarbose group (25 mg twice daily) 
  • All subjects received diet and exercise instruction by a registered dietitian

Statistical Analysis

  • Study results expressed as mean ± standard deviation
  • Decrease in glycemic level expressed as percentage
  • Mann Whitney test performed between groups for assessment of significance
  • P <0.05 considered statistically significant
Data Collection Summary:

Timing of Measurements

  • Baseline
  • Plasma glucose measured monthly after randomization
  • A1C measured every 3 months after randomization
  • Various measures done every 6 months

Dependent Variables

  • Plasma glucose (fasting and postprandial)
  • A1C

Independent Variables

  •  Study group intervention 

Control Variables

  •  Not discussed
Description of Actual Data Sample:

Initial N: 234 (94 male)

Attrition (final N):  Not identified in paper

Age: Not discussed

Ethnicity: Indian

Other relevant demographics: 128 subjects had positive family history of diabetes

Anthropometrics:  Some mean baseline data was given for all groups combined, but not per group.

Location: Ramakrishna Mission Seva Pratisththan

 

Summary of Results:

 

Comparison of Different Groups according to % changes

Variables

Intensive Lifestyle only

 n= 90

Metformin plus intensive lifestyle

n=48

Rosiglitazone plus intensive lifestyle

n=48

Acarbose plus intensive lifestyle

n=48 

Statistical Significance of Group Difference

 Fasting plasma glucose (FPG)

 9.44  5.49  11.22  2.92 (increase)  p>0.01

 Postprandial plasma glucose (PPPG)

 29.98

 32.07  34.95

 9.35

  p>0.01

A1C

 5.92  6.95  7.81  6.45   p>0.01

Body mass index (BMI)

 11.2

 11.9  11.73

 10.66

  p>0.01

Other Findings

  • Thirty-eight percent of the lifestyle group remained euglycemic; and the other groups remained euglycemic (% not included).
  • No subject was diagnosed with diabetes during the study period of three years.
  • No diabetes complication was seen in any subject (during the study).

 

Author Conclusion:
From this study it is evident that deterioration of elevated post challenge glucose can be delayed.
Funding Source:
Reviewer Comments:
It is unclear if the 'Intensive Lifestyle group' diet and exercise instruction was any different from the diet and exercise instruction given to the medication groups.  Authors state the most successful method was lifestyle change, however it is unclear how this conclusion was made.  The paper was a study brief;  study details were not present.  The data included in the paper is not defined as to when it was measured (3 year data?).
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? ???
  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? ???
  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? 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? No
  4.1. Were follow-up methods described and the same for all groups? No
  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%.) No
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? ???
  4.4. Were reasons for withdrawals similar across groups? ???
  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? ???
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? ???
  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.) ???
  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? ???
  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? 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? ???
  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? 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)? ???
  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? ???
  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? No
  9.1. Is there a discussion of findings? No
  9.2. Are biases and study limitations identified and discussed? No
10. Is bias due to study's funding or sponsorship unlikely? ???
  10.1. Were sources of funding and investigators' affiliations described? No
  10.2. Was the study free from apparent conflict of interest? ???