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Trial registered on ANZCTR


Registration number
ACTRN12619001374156
Ethics application status
Approved
Date submitted
9/09/2019
Date registered
9/10/2019
Date last updated
9/10/2019
Date data sharing statement initially provided
9/10/2019
Type of registration
Retrospectively registered

Titles & IDs
Public title
Development and evaluation of lifestyle interventions for patients with pre-diabetes
Scientific title
Development and evaluation of an Acceptance and Commitment Therapy (ACT) based lifestyle education intervention for patients with pre-diabetes: A randomised controlled trial
Secondary ID [1] 299222 0
Nil
Universal Trial Number (UTN)
U1111-1239-9020
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Pre-diabetes 314346 0
Condition category
Condition code
Metabolic and Endocrine 312684 312684 0 0
Diabetes

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Participants were randomly assigned to 1 of 3 intervention conditions: ACT and Education (ACT/ED), Education Only (ED Only) or Standard Care (this is described in the control treatment section)

The ED Only and ACT/ED interventions were designed to be delivered in a brief, manualised, workshop format, based around a power-point presentation. Both of the interventions were 4.5 hours duration and delivered across two morning sessions held on consecutive weeks. The first session was 2 hours and the second was 2.5 hours.

Due to the researcher being unable to access a single venue that was available for the scheduled workshop dates and times, the workshops were held at two venues; Wharerata Conference Facilities at Massey University and The Bank of New Zealand Conference Facilities located in central Palmerston North.

The ED Only and ACT/ED groups were facilitated by the lead researcher, a female senior Clinical Psychologist, and a female senior Dietitian with the Manawatu Diabetes Trust. The Clinical Psychologist had 8 years experience working with patients affected by long-term physical health conditions. Throughout the course of the study, she was employed by the Massey University Long-term Health Conditions Service; a psychology service that provides assessment and therapeutic support for adults with a variety of long-term health conditions, including diabetes and cardiovascular disease. In addition, prior to embarking on this research, she had attended advanced training opportunities focused on the use of ACT with patients with long-term health conditions. The Dietitian had over 10 years experience working with people with diabetes and was employed by the Manawatu Diabetes Trust.

Intervention 1: ED Only
The ED Only intervention was developed based on pre-diabetes advice/guidelines provided by the New Zealand Ministry of Health, and then extended for the purposes of this research by including key lifestyle messages/goals taken from international pre-diabetes intervention trials that have been demonstrated to reduce diabetes risk. The aim of this intervention was to provide participants with education about what it means to have pre-diabetes and diabetes, risk factors for the development of type 2 diabetes (with an emphasis on diet and exercise), potential physical/psychological consequences of developing T2 Diabetes, and lifestyle changes that can be made to reduce their risk.

Intervention 2: ACT plus Education (ACT/ED)
This intervention protocol was based on an existing protocol developed by Gregg and colleagues (Gregg et al., 2007) for client’s with type 2 diabetes, which was modified for patients with pre-diabetes.
Session one of this covered the same areas as the ED Only intervention but in a condensed form. Session two explored participants' personal values related to managing pre-diabetes; helped them connect these values to concrete behavioural goals; and taught them skills to deal with thoughts and feelings that functioned as barriers to attaining/maintaining lifestyle changes to improve their health. Session 2 involved teaching (through a combination of didactic methods, metaphor, and experiential exercises) core ACT therapeutic processes: values, self as context, defusion, acceptance, contact with the present moment, values, and committed action. The examples and/or metaphors used were tailored to issues identified in the literature to be relevant for individuals with pre-diabetes.

For the ACT/ED and ED Only interventions, a PowerPoint presentation accompanied the facilitator manual. This presentation was adapted from an existing pre-diabetes workshop developed by Kauri Health (a local integrated family heath centre), reviewed and updated by Manawatu/Horowhenua Diabetes Trust, and endorsed by a Diabetes Lifestyle Centre Nurse Practitioner with MidCentral District Health). The PowerPoint was based on pre-diabetes advice/guidelines for the lifestyle management of pre-diabetes published by the New Zealand Ministry of Health (2013). This PowerPoint was previously used by the Manawatu Diabetes Trust in workshops for consumers with pre-diabetes.

Group guides were provided to participants during both ACT/ED and ED Only workshops to facilitate effective learning. The group guides contained all of the PowerPoint slides shown during the workshops, the key messages presented by the facilitators, and the handouts and exercises used.

During the workshops, all participants also received a Diabetes New Zealand portion size plate, a wallet-sized food label reading card, a calorie and fat counter (Borushek, 2014), and carbohydrate counting cards. These tools were designed to facilitate ongoing learning post-intervention.

Additionally, at the start of the first workshop, all participants were given an information pack containing seven pamphlets created by Diabetes New Zealand. These were the same pamphlets given to participants in the Standard Care condition (see below).

Treatment fidelity
The use of a treatment manual, which specified the duration and timing of the intervention components and provided sample dialogue to assist facilitators with information delivery, was intended to increase treatment fidelity and consistency. In addition, the primary researcher was a co-facilitator of the workshops, which allowed her to monitor the dietician’s consistency with and adherence to the manual.
Intervention code [1] 315519 0
Lifestyle
Comparator / control treatment
Standard Medical Care
Participants assigned to this condition did not attend a workshop. On recruitment to the trial (3 months before attending their first follow-up session) they attended an initial assessment session, where they completed their baseline measures. At the end of this session, they were given a series of brochures created by Diabetes New Zealand and the New Zealand Heart Foundation, which provided them with information about what it means to have pre-diabetes and diabetes, along with lifestyle changes they could make to reduce their risk of developing type 2 diabetes in the future. Throughout the study, they continued to receive standard medical care/follow-up, as needed, through their GP Practice in line with guidelines for pre-diabetes management provided by the New Zealand Ministry of Health (2013). These guidelines suggest GPs and Practice Nurses provide advice when patients attend scheduled appointments pertaining to the benefits of regular exercise, and maintaining a healthy weight and diet.
Control group
Active

Outcomes
Primary outcome [1] 321336 0
Hemoglobin A1C (HbA1c) results
HbA1c was assessed via venous blood samples, which were drawn and analysed by an accredited local laboratory, Medlab. Participants were given a referral form and asked to attend one of several Medlab facilities in the MidCentral region where a trained Phlebotomist took blood samples. HbA1c gives an indication of glycaemia over the 8 to 12 week life span of the red blood cells, by measuring the number of glucose molecules attached to haemoglobin
Timepoint [1] 321336 0
Baseline (1 week prior to attending the interventions)
3 months after intervention delivery (primary endpoint)
6 months after intervention delivery
Primary outcome [2] 321486 0
Body Mass Index (BMI) results
BMI is a measure of the ratio of body fat to weight. BMI was calculated using the participants’ height and weight. The formula used was the participant’s weight in kilograms divided by their height in metres squared.

Body weight was assessed by the lead researcher using Weight Watchers calibrated bioelectrical impedance scales. Patients were requested to wear light, loose clothing and remove their shoes before being weighed. Weight was recorded in kilograms to the nearest 0.1 kg.
Height was measured using a Seca 213 portable stadiometer on a firm even floor. Participants were requested to remove their shoes and stand up straight with their head facing straight ahead and their heels, shoulders and buttocks contacting the back of the stadiometer. Measurements were taken to the nearest millimetre.
Timepoint [2] 321486 0
Baseline (1 week prior to attending the interventions)
3 months after intervention delivery (primary endpoint)
6 months after intervention delivery
Primary outcome [3] 321487 0
Lipid results
Venous blood samples were taken by a trained phlebotomist and analysed in a certified Med Lab facility. A full lipid profile was obtained; total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and triglycerides.
When analysing lipid results, the following Ministry of Health Guidelines (Ministry of Health, 2012) were used to identify participants at increased cardiovascular risk. Levels below, or in the case of HDL-C, greater than these were classified within the normal range.
1. Total cholesterol greater than 4.0 mmol/L
2. LDL cholesterol greater than 2.0 mmol/L
3. HDL cholesterol less than 1.0 mmol/L
4. Triglycerides greater than 1.7 mmol/L
Timepoint [3] 321487 0
Baseline (1 week prior to attending the interventions)
3 months after intervention delivery (primary endpoint)
6 months after intervention delivery
Secondary outcome [1] 374694 0
Scores on The Dietary Instrument for Nutrition Education (DINE) (Roe, Strong, Whiteside, Neil, & Mant, 1994).
The DINE was used to assess fat and fibre intake. The DINE assesses the dietary intake of 19 food groups that are frequently consumed in western cultures and provides overall scores for fat (broken down into saturated and unsaturated fat) and fibre intake. A score is assigned to each food group based on the nutritional content of an average portion size and how often it is consumed. Participants can be categorised according to high, medium and low levels of fibre and fat consumption (Little & Margetts, 1996).
The
Timepoint [1] 374694 0
Baseline (1 week prior to the intervention)
3 months following intervention delivery
6 months following intervention delivery
Secondary outcome [2] 374695 0
Scores on the Short Form International Physical Activity Questionnaire (SF-IPAQ).
The self-administered short form of the SF-IPAQ was used to assess physical activity levels. The SF-IPAQ was developed by an international consensus group who aimed to construct a measure that was internationally relevant for monitoring physical activity across cultures (Craig et al., 2003). The SF-IPAQ consists of 9 items. Instructions request participants to report the number of days during the previous week they spent engaged in vigorous, moderate or walking activities, and the amount of time ‘usually’ spent engaged in that activity on one of those days. Participants are also asked about the amount of time spent sitting or lying down as a measure of sedentary behaviour.
Timepoint [2] 374695 0
Baseline (1 week prior to the intervention)
3 months following intervention delivery
6 months following intervention delivery
Secondary outcome [3] 374696 0
Overall Score on the Satisfaction with Life Scale (SWLS) {Diener, 1985 #212.
The SWLS was developed as a brief measure of general/global satisfaction with life. It consists of five statements (e.g., “The conditions of my life are excellent”), which participants rate their level of agreement/disagreement with on a 7 point Likert type scale (1 = strongly disagree, 7 = strongly agree). Scores can range from 5 to 35, with higher scores indicating greater levels of life satisfaction. Scores in the range of 5 to 9 represent extreme dissatisfaction, and scores between 31 and 35 indicate extreme satisfaction. A score of 20 is considered neutral, suggesting the participants are “equally” satisfied and dissatisfied with their life {Diener, 1985)
Timepoint [3] 374696 0
Baseline (1 week prior to the intervention)
3 months following intervention delivery
6 months following intervention delivery
Secondary outcome [4] 375089 0
Scores on the The WHOQOL-BREF- Australian Version (Murphy, Herrman, Hawthorne, Pinzone, & Evert, 2000).
The WHOQOL-Bref is a self-report measure designed to assess perceptions of health-related quality of life.The WHOQOL-Bref is composed of 26 items that were taken from the original WHOQOL-100 questionnaire. The WHOQOL-Bref produces 4 domain scores, which measure quality of life across physical, psychological, social and environmental domains. Items 1 and 2 of the WHOQOL are scored separately. These questions refer to the participant’s overall satisfaction with their health and overall perception of their quality of life.
Timepoint [4] 375089 0
Baseline (1 week prior to the intervention)
3 months following intervention delivery
6 months following intervention delivery
Secondary outcome [5] 375090 0
Scores on the anxiety and depression sub-scales of the The Hospital Anxiety and Depression Scale (HADS) (Zigmond & Snaith, 1983) were used to assess changes in anxiety and depression.
Timepoint [5] 375090 0
Baseline (1 week prior to the intervention)
3 months following intervention delivery
6 months following intervention delivery
Secondary outcome [6] 375091 0
Overall score on the Distress Tolerance Scale (DTS; Simons & Gaher, 2005) was used to assess participants distress tolerance.
Timepoint [6] 375091 0
Baseline (1 week prior to the intervention)
3 months following intervention delivery
6 months following intervention delivery
Secondary outcome [7] 375092 0
Breath holding duration.
A breath holding task was also used as a behavioural measure of distress tolerance. This task involved requesting the participant to hold their breath for as long as possible while being timed with a stopwatch. This procedure is then repeated following a 5 minute rest period. The maximum breath holding duration is documented as the distress tolerance score.
Timepoint [7] 375092 0
Baseline (1 week prior to the intervention)
3 months following intervention delivery
6 months following intervention delivery
Secondary outcome [8] 375093 0
Psychological inflexibility and experiential avoidance were assessed using the Acceptance and Action Pre-diabetes Questionnaire, AAPDQ; a 10 item self-report measure. The AAPDQ is a modified version of the Acceptance and Action Diabetes Questionnaire (AADQ), which was developed by Gregg (2007) to assess levels of experiential avoidance for patients with type 2 diabetes.
Timepoint [8] 375093 0
Baseline (1 week prior to the intervention)
3 months following intervention delivery
6 months following intervention delivery
Secondary outcome [9] 375094 0
Overall score on the pre-diabetes knowledge test. This test was adapted from the Michigan Diabetes Research and Training Centre’s Brief Diabetes Knowledge Test (Diabetes Research and Training Center, 1998) by the Manawatu Diabetes Trust. It has been previously used by Diabetes Trust to evaluate participants’ retention of the information presented during their pre-diabetes education workshops.
Timepoint [9] 375094 0
Baseline (1 week prior to the intervention)
At the end of the intervention
3 months following intervention delivery
6 months following intervention delivery
Secondary outcome [10] 375095 0
Intervention acceptability/credibility was assessed using a brief Participant Satisfaction Questionnaire. This required participants to rate on 5 point Likert scales how effective and helpful they found the treatment, their overall level of satisfaction with the intervention, and whether they would recommend the intervention to a friend. Scales ranged from 1 (not at all effective/helpful/satisfied) to 5 (very effective/helpful/satisfied).
Timepoint [10] 375095 0
Directly post-intervention, a the end of the second workshop. This was only administered for those who attended the ACT/ED and ED Only interventions
Secondary outcome [11] 375096 0
Waist circumference
Waist circumference was measured using a Seca tape measure. Measurements were taken while the participant was standing up straight and attired in light clothing. The measurement was taken between the rib and iliac crest to the closest 0.1 cm.
10.10.1.4 Lipids.
Timepoint [11] 375096 0
Baseline (1 week prior to the intervention)
3 months following intervention delivery
6 months following intervention delivery
Secondary outcome [12] 375097 0
Body weight
This was assessed using Weight Watchers calibrated bioelectrical impedance scales. Patients were requested to wear light, loose clothing and remove their shoes before being weighed. Weight was recorded in kilograms to the nearest 0.1 kg.
Timepoint [12] 375097 0
Baseline (1 week prior to the intervention)
3 months following intervention delivery
6 months following intervention delivery

Eligibility
Key inclusion criteria
Inclusion criteria required that patients were:
1. Over the age of 18
2. Fluent in spoken and written English
3. Had a formal classification of pre-diabetes from a registered medical professional.
The prediabetes inclusion criteria were based on World Health Organisation (WHO) criteria for pre-diabetes classification. This requires patients to have an impaired fasting glucose (IFG between 6.1 and 6.9 mmol-1 inclusive) and an impaired glucose tolerance (IGT 2 hour postprandial glucose concentration between 7.8 and 11 mmol), and/or an HbA1c between 41 and 49.
Minimum age
18 Years
Maximum age
No limit
Sex
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria

1. Cognitively impaired.
2. At risk of harm to/from themselves or others (i.e., suicidal/homicidal ideation).
3. Comorbid medical diagnosis or condition that is terminal and likely to be fatal within one year.
4. Already participating in a formal pre-diabetes lifestyle education intervention.
5. Receiving psychiatric or psychological intervention at the time of recruitment or has a severe psychiatric disorder (e.g., schizophrenia).
6. Meets criteria for type 2 diabetes. Again, this is based on WHO criteria (i.e., IFG greater than or equal to 7mmol/l, and/or 2-hour plasma glucose of greater than or equal to 11.1 mmol/l and/or HbA1c of 50 mmol/l or greater).

Study design
Purpose of the study
Prevention
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Central randomisation by computer
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation using a randomisation table created by computer software (i.e. computerised sequence generation)
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s


Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint/s
Efficacy
Statistical methods / analysis
A priori power analysis using G* 3.1.2 software (Erdfelder, Faul, & Buchner, 1996) was conducted to determine recruitment targets. It was calculated that a sample size of 158 (53 per condition) would be required to detect an effect size of 0.50 (Cohen’s f), with 80% power at a 5% significance level; this is considered a medium effect size. Based on previous research exploring the impact of an ACT/Lifestyle Education intervention on diabetes self-management, effect sizes in the medium range were expected (Gregg et al., 2007). Gregg and colleagues reported a significant moderate effect, for ACT/ED over Education Only in the achievement of diabetic control (defined as HbA1c < 60)(Gregg et al., 2007). Based on this finding and allowing for a attrition rate of approximately 20%, as seen in the Finnish Diabetes Prevention Study (Lindstrom et al., 2003), the intention was to recruit 189 participants for the present study (63 per intervention).
All numerical data were analysed using SPSS (version 24) for Windows. A series of mixed between-within subjects analyses of variance (ANOVA) were conducted to compare the effectiveness of the 3 interventions (Standard Care, Lifestyle Education Only, Education and Acceptance and Commitment Therapy) over time on the dependent variables.

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
Actual
9/02/2015
Date of last participant enrolment
Anticipated
Actual
30/03/2016
Date of last data collection
Anticipated
Actual
31/10/2016
Sample size
Target
189
Accrual to date
Final
87
Recruitment outside Australia
Country [1] 21849 0
New Zealand
State/province [1] 21849 0
Manawatu

Funding & Sponsors
Funding source category [1] 303762 0
Hospital
Name [1] 303762 0
Palmerston North Hospital
Country [1] 303762 0
New Zealand
Primary sponsor type
University
Name
Massey University Psychology Department, Palmerston North
Address
Massey University Psychology Clinic
Bernard Chambers B
Library Road
Massey University
Palmerston North 4474
Country
New Zealand
Secondary sponsor category [1] 303882 0
None
Name [1] 303882 0
Address [1] 303882 0
Country [1] 303882 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 304285 0
Health and Disability Ethics Committee, Central Region
Ethics committee address [1] 304285 0
Ministry of Health
Health and Disability Ethics Committees
PO Box 5013
Wellington 6140
Street address:
133 Molesworth Street
Thorndon
Wellington 6011
Ethics committee country [1] 304285 0
New Zealand
Date submitted for ethics approval [1] 304285 0
16/07/2014
Approval date [1] 304285 0
27/08/2014
Ethics approval number [1] 304285 0
14/NTA/126

Summary
Brief summary
The primary purpose of this study is to develop and adapt two intervention approaches for patients with pre-diabetes; lifestyle education alone and lifestyle education combined with Acceptance and Commitment Therapy (ACT). The goal of the ACT/Education approach is to connect participants’ lifestyle goals to personally meaningful values, and equip them with skills to deal with difficult emotions that can function as barriers to goal attainment. A randomised controlled design is used to compare the effectiveness of these approaches with the provision of standard medical care. It is predicted that ACT and Education combined will produce greater improvements in physiological indicators of pre-diabetes management, self-report measures of lifestyle change (diet and exercise), quality of life and emotional functioning (depression, anxiety and distress tolerance).
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 96394 0
Ms Sarah Malthus
Address 96394 0
Massey University Psychology Clinic
Bernard Chambers B
Library Road
Palmerston North 4442
Country 96394 0
New Zealand
Phone 96394 0
+64 0273420581
Fax 96394 0
Email 96394 0
[email protected]
Contact person for public queries
Name 96395 0
Sarah Malthus
Address 96395 0
Massey University Psychology Clinic
Bernard Chambers B
Library Road
Palmerston North 4442
Country 96395 0
New Zealand
Phone 96395 0
+64 0273420581
Fax 96395 0
Email 96395 0
[email protected]
Contact person for scientific queries
Name 96396 0
Sarah Malthus
Address 96396 0
Massey University Psychology Clinic
Bernard Chambers B
Library Road
Palmerston North 4442
Country 96396 0
New Zealand
Phone 96396 0
+64 0273420581
Fax 96396 0
Email 96396 0
[email protected]

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment


What supporting documents are/will be available?

No Supporting Document Provided



Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
No additional documents have been identified.