EAL

PDM: Prediabetes (2013)

Citation:

Yates T, Davies MJ, Sehmi S, Gorely T, Khunti K. The Pre-diabetes Risk Education and Physical Activity Recommendation and Encouragement (PREPARE) programme study: Are improvements in glucose regulation sustained at 2 years? Diabet Med. 2011; 28(10); 1,268-1,271.

PubMed ID: 21672008

Study Design:

Randomized Controlled Trial

Class:

A - Click here for explanation of classification scheme.

Quality Rating:

POSITIVE: See Quality Criteria Checklist below.

Research Purpose:

To determine whether improvements in glucose regulation following the PREPARE structured education program were sustained at 24 months.

Inclusion Criteria:

Overweight and obese individuals with impaired glucose tolerance who completed the PREPARE program in March 2007 and accepted the invitation to a further annual screening to assess their glycemic status 24 months after entry into the PREPARE study.

Exclusion Criteria:

Those diagnosed with type 2 diabetes prior to the additional (24 month) annual screening visit.

Description of Study Protocol:

Recruitment

Overweight and obese individuals with impaired glucose tolerance were recruited from population-based type 2 diabetes screening programs. Those who completed the PREPARE program and were not diagnosed with type 2 diabetes were invited to participate in a further annual screening to assess their glycemic status 24 months after entry into the PREPARE program

Design

Randomized controlled trial. The PREPARE program randomized participants into three groups [the control group, the education group (received a standard three-hour group-based structured education program promoting increased physical activity) and the education with pedometer group, which had an enhanced self-regulation education component along with pedometer use to aid goal setting and self monitoring]. Both intervention groups also received brief one-to-one counseling at three and six months. At each measurement time point (baseline and 24 month follow-up), individuals underwent an oral glucose tolerance test following standard procedures. Body weight and waist circumference were also measured.

Blinding Used

Lab personnel were blinded to treatment group.

Intervention

Control group
Education group (received a standard three-hour group-based structured education program promoting increased physical activity)
Education with pedometer group which had an enhanced self-regulation education component along with pedometer use to aid goal setting and self monitoring
Both intervention groups also received brief one-to-one counseling at three and six months.

Statistical Analysis

Between group comparisons of change in measured outcomes in the intervention groups compared with the control groups were conducted using simple a priori contrasts with analysis of covariance procedures; baseline data were included as a covariate and further adjustments were made to determine important differences between groups regarding ethnicity and anti-hypertensive medication usage
A log rank test, incorporating published data of follow-up rates within the first 12 months was used to determine the relative risk of developing diabetes in the intervention groups compared with the control group.

Data Collection Summary:

Timing of Measurements

Measurements were taken at baseline of this study (completion of the PREPARE program) and at the 24-month follow-up (12 months after completion of the PREPARE program).

Dependent Variables

Change in glucose tolerance measured by two-hour post challenge glucose in mmol per L
Change in fasting glucose measured in mmol per L
Body weight change measured to nearest 0.1kg
Waist circumference measured at midpoint between the lower costal margin and iliac crest to nearest 0.5cm.

Independent Variables

Education group received a standard three-hour group based structured education program, aimed at promoting increased physical activity particularly walking, delivered by two trained educators to groups of up to 10 individuals. The walking portion aligned with the minimum recommendations for health; specifically 30 minutes of moderate-intensity physical activity on at least five days per week. Also, the program addressed key perceptions and knowledge of impaired glucose tolerance and targeted the perceived effectiveness of exercise as treatment for impaired glucose tolerance, walking self-efficacy beliefs, barriers to walking and self-regulatory strategies such as action planning and goal setting. Additionally, participants received brief one-to-one counseling at three and six months.
Education with pedometers group received the same three-hour structured education program, but with an enhanced self-regulation section that incorporated personalized steps per day targets and pedometer use to aid goal setting and self-monitoring. Additionally, participants received brief one-to-one counseling at three and six months.
Control group received an advice leaflet.

Description of Actual Data Sample:

Initial N: 98 subjects were randomized to one of three groups.
Attrition (final N): 73 (26 female, 47 male) after two years, representing 74% of PREPARE program participants
Age: 65±8 years
Ethnicity: 21% South Asian
Anthropometrics: BMI 29.3±4.8kg/m²
Location: United Kingdom.

Summary of Results:

Key Findings

Significant reductions in two-hour glucose of -1.6mmol per L (95% CI: -0.4 to -2.7) in education with pedometer group
Fasting glucose tended toward significance in education with pedometer group
No significant differences were seen with the education-only group.

**Baseline, Follow-up and the Associated Intervention Effect for Glucose, Body Weight and Waist Circumference at 24 Months**
	*Control		^¥Intervention #1 (Education)		Intervention #2 (Education and Pedometers)
Variable	Baseline	24-month Follow-up	Baseline	24-month Follow-up	Baseline	24-month Follow-up	Adjusted Intervention Effect (Intervention #1 vs. Control)	P	Adjusted Intervention Effect (Intervention #2 vs. Control)	P
Two-hour glucose (mmol per L)	8.8±1.9	8.9±2.4	8.1±1.8	8.1±2.3	8.8±2.3	7.3±2.2	-0.4 (-1.6 to 0.8)	0.50	1.6 (-0.4 to -2.7)	0.01
Fasting glucose (mmol per L)	5.7±0.5	5.7±1.0	5.6±0.6	5.5±0.7	5.6±0.6	5.4±0.7	-0.1 (-0.4 to 0.2)	0.58	-0.3 (0.7 to 0.0)	0.07
Body weight (kg)	80.8±15.5	80.0±15.9	80.4±15.3	79.4±15.5	81.3±16.9	82.0±15.4	0.2 (-2.7 to 3.1)	0.89	1.5 (-1.3 to 4.3)	0.29
Waist circumference (cm)	103±9	101±9	103±13	100±13	101±12	100±12	-1(-4 to 2)	0.46	2 (-1 to 5)	0.18
Data displayed as mean ± SD or mean (95% CI). All reported intervention effects were adjusted for baseline value. *Three individuals had data imputed as a result of a diagnoses of type 2 diabetes during the first 12 months of the study. ¥One individual had data imputed as a result of a diagnoses of type 2 diabetes during the first 12 months of the study.

Other Findings

Six individuals in the control group, four in the education group and two in the education-with-pedometer group were diagnosed with type 2 diabetes over the 24 month period
This represents a 19% and 61% reduction in the relative risk of developing diabetes in the education and the education-with-pedometer groups, respectively.

Author Conclusion:

Improvements in glucose regulation following a pragmatic group-based structured education with pedometer use were sustained at 24 months.

Funding Source:

Government:

National Institute of Health Research Collaboration for Leadership in Applied Health Research and Care

Not-for-profit

Diabetes UK

Other non-profit:

Reviewer Comments:

26% dropout after two years of follow-up. Author cautions the observed relative risk for developing diabetes in the intervention vs. control groups should carefully interpreted due to the small number (12) of cases.

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?		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?	???
	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?	Yes
	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?	N/A
	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?	Yes
	10.2.	Was the study free from apparent conflict of interest?	Yes