Table 2 From SLIM to MetSLIM: an overview of considerations and choices in the protocol design process

Objective

To study whether a diet/physical activity intervention programme can improve glucose tolerance in subjects at high risk of developing type 2 diabetes mellitus.

Because of the overlapping risk factors, the initial idea of the MetSLIM study was to focus on persons with metabolic syndrome (MetS), which is associated with an increased risk both of T2DM and of CVD [20]. However, screening for MetS might impose too high a burden on low SES individuals to participate in the study because of:

To evaluate the effectiveness of an adapted version of the SLIM lifestyle programme to reduce elevated waist circumference and improve other components of the metabolic syndrome in individuals with low socioeconomic status of different ethnic origins.

- unfamiliarity with MetS

- time-consuming screening necessary before potential participants know whether they can actually participate (waiting for laboratory results).

Primary outcome:

Waist circumference was considered because it is:

Primary outcome:

Change in glucose tolerance (2-h plasma glucose)

- visible for potential participants and therefore easy to communicate

Change in waist circumference

- one of the components of the metabolic syndrome and a risk factor for cardiometabolic diseases [21].

Study design

Setting:

Distance can be a barrier to participation; target group prefers nearby location, possibly a familiar place. The two universities involved in this study are not located in deprived neighbourhoods. Besides, the number of ethnic minorities living in the cities where the two universities are located is relatively small.

Setting:

At the university

In the community

Design:

RCT design does not seem appropriate because:

Design:

Randomized controlled trial (RCT)

- target group is probably unfamiliar with randomization, which could easily provoke dissatisfaction if participants were randomly allocated to intervention and control group within one community

Quasi-experimental study

- participants are allowed to bring a friend or family member to different intervention activities (for social support), which could result in spill-over.

Duration:

The duration of MetSLIM should be shorter given the limited time and budget.

Duration:

4.1 year (range 3–6years)

12 months

Study population

Inclusion/exclusion criteria:

See Table 1

Inclusion/exclusion criteria:

See Table 1

See Table 1

Recruitment strategies:

Recruitment strategies should be adapted to needs of target group, taking into account that:

Recruitment strategies:

- Potentially eligible persons from a large existing cohort monitoring health and disease in the general population were approached to participate

- GP is indicated as trustworthy and valued person for the target group [22,23]

- Invitation letter from own GP

- a personal approach seems to be appreciated

- Personal approach in community centres

- Through advertisements in the local newspaper

- letterbox drops do not seem to work for this group [24].

Intervention group

Nutrition advice:

Target group preferred group delivery of nutrition advice [25]; therefore group meetings should be added. The topics of the extra group meetings should be related to identified barriers, like financial costs and social occasions [25,26].

Nutrition advice:

- One group meeting a year

- Four group meetings a year, of which one is an introduction/kick-off meeting

- Four 1-hour sessions of individual advice in one year

The spreading of the four hours of individual advice should be flexible. The involved professionals indicated that they preferred to vary the number and length of consultations to the individual needs of the client. This is in accordance with daily practice.

- Four hours of nutrition advice spread over the year, with regard to the needs of the individual

Physical activity lessons:

Target group indicated that they preferred to be physically active with persons of the same gender [25,27], age and physical condition [25]. Target group indicated that creating a supportive environment can encourage lifestyle change [26].

Physical activity lessons:

- Once or twice a week

- Once or twice a week

- Provided at the gym on the grounds of the university

- Provided in the community

- In special SLIM groups

- In special MetSLIM groups

- Men and women separately

- Possibility to bring friend or family member

No participation fee

Some local health professionals preferred a participation fee for participating in the lifestyle programme. Their experience was that persons get used to getting everything for free and will switch to other free programmes once a programme is not free anymore. This could be a problem for the maintenance of programmes. At the same time, the target group indicated that financial cost can be a barrier to a healthy lifestyle, and researchers were concerned about not recruiting enough participants.

No participation fee

Control group

Activities control programme:

Because of possible low literacy level of the target group, an information meeting instead of only written materials should be considered.

Activities control programme:

- No additional appointments are scheduled, apart from the annual visits for follow-up measurements

- One group meeting with a dietician about nutrition

- Participants received oral and written information about the beneficial effects of a healthy diet, weight loss and increased physical activity at the appointment for baseline measurements

- Participants will receive oral and written information about the beneficial effects of a healthy diet, weight loss and increased physical activity (where possible, in their mother tongue)

Measurements

Physical measurements:

The measurements were reconsidered taking into account:

Physical measurements:

- Anthropometric measurements

- practical feasibility of doing the measurements at different locations, in the community

- Anthropometric measurements

- Blood sampling

- possibility of relocating measurements equipment

- Blood and urine sampling

- Blood pressure

- participants’ unfamiliarity with different measurements.

- Blood pressure

- Oral Glucose Tolerance Test (OGGT)

- 12-lead resting ECG

- Incremental exhaustive exercise test on an electronically braked bicycle ergometer

Physical activity:

Difficulties were expected with filling in diaries because of illiteracy. Additional information should be gathered about determinants of behaviour.

Physical activity:

- SQUASH

- SQUASH

- 3-day PA record

- Accelerometers

- Questionnaire on determinants of physical activity

Dietary habits:

Difficulties were expected with filling in diaries because of illiteracy. Additional information should be gathered about determinants of behaviour.

Dietary habits:

- FFQ

- Ethnicity-matched FFQ

- 3-day food record

- Questionnaire on determinants of healthy diet

Quality of life:

The SF-36 is considered as acceptable to measure quality of life among these populations [28,29].

Quality of life:

SF-36 questionnaire

SF-36 questionnaire

Economic evaluation:

The economic evaluation of a lifestyle programme is important in the context of possible future implementation of the programme. Because it is not known who might be willing to pay for the programme, it is important to consider the costs and effects from different perspectives.

Economic evaluation:

Cost-effectiveness analysis was conducted from a healthcare perspective only [13].

Cost-effectiveness analysis and cost-utility analysis will be done from a societal perspective and a healthcare perspective.

Process evaluation:

Adherence to the nutrition and exercise part of to the lifestyle programme was reported in SLIM [30]. An elaborate process evaluation was lacking however. MetSLIM should include an elaborate process evaluation.

Process evaluation:

Limited data available

Elaborate process evaluation by means of:

- Researchers’ logbooks

- Registration forms including an attendance list

- Non-response survey

- Drop-out questionnaire

- Participants’ questionnaire

Additional considerations

Involved staff:

Staffing should be matched with either ethnicity or gender of the participants, depending on the availability of staff and the needs of participants:

Involved staff:

- Dutch researcher

- fluency of participants’ Dutch language might be low

- Dutch researcher(s)

- Dutch dietician

- dietician should be able to tailor dietary advice to individuals’ (possibly traditional) eating habits and should be familiar with traditions bound to Islam

- Ethnicity-matched research assistants

- Sports instructor not gender matched

- gender-matched sports instructors are preferred by some Turkish and Moroccan females.

- Ethnicity-matched dieticians

- Gender-matched sports instructors

Language of information material and questionnaires:

The information materials and questionnaires should be translated because of possible problems with fluency in the Dutch language.

Participants can opt for information in one or more of the following languages:

Dutch

- Dutch

- Standard Arabic

- Turkish

Receiving results of measurements:

Participation in health checks seemed to be popular among the target group according to various health professionals; receiving results could help to motivate control group participants to participate in the study’s baseline and final measurements. Apart from the motivational aspect, it is common in healthcare practice that patients are informed about the results of regular blood tests.

Receiving results of measurements:

Yes

Yes