The effectiveness of a targeted diabetes prevention programme for Hindustani Surinamese, consisting of screening followed by a lifestyle intervention

In the Netherlands, a particularly high prevalence of diabetes mellitus (DM) is
found among Hindustani: the prevalence
among the Hindustani is four times as high as that among the ethnic Dutch in
the same age group. In accordance, studies have shown that the prevalence of
prediabetes, characterised by impaired fasting glucose (5.6-7.0 mmol/l) or
impaired glucose tolerance (2-h OGTT value 7.8 -11.1 mmol/l), is also high in
the Hindustani populations. Persons with prediabetes are at high risk of
developing DM and DM-related morbidity.
Previous studies have convincingly shown that intensive lifestyle interventions
prevent the onset of DM among persons with prediabetes. However, the
effectiveness of interventions depends on the characteristics of the population
studied and the strategy used. In general, interventions aimed at the general
(white) population are less effective in specific migrant groups, such as the
Hindustani. Therefore, prevention programmes for DM among the Hindustani
population should be targeted to the characteristics of that population.
In a recent feasibility study, we have developed such a prevention programme
for the Hindustani population, which consists of a targeted screening and a
targeted lifestyle intervention [(Zonmw project 6130.0034), unpublished]. The
design of this programme takes the specific epidemiological and cultural
characteristics of the Hindustani population into account. An initial
evaluation showed that the intensive, targeted approach used is successful: 43%
of all eligible persons were screened. Of those, 40% had prediabetes and were
eligible for the lifestyle intervention.

However, prior to further implementation of this programme, insight into the
effectiveness is needed.
Specifically, what is the effectiveness of a targeted prevention programme with
regard to the prevention of DM and *in the long-term- DM-related morbidity,
what are the costs vs. benefits, and what are the side-effects of the
prevention programme?

To investigate these issues, we will invite approximately 6000 Hindustani
Surinamese men and women aged 18-60 to be screened by means of a fasting plasma
glucose measurement and oral glucose tolerance test. Participants with
prediabetes (approximately n=500) will subsequently be invited for a randomised
controlled trial in which a group receiving the intensive lifestyle
intervention will be compared with a control group receiving simple, generic
lifestyle advice. In case of suspected DM, participants will be referred to
their GP for care. Moreover, a sample of those with normoglycemia at baseline
will be invited for re-screening after 3 years.

To evaluate the effectiveness of the intervention, data will be collected on
fasting glucose, HbA1c, insulin and post-load glucose concentrations at
baseline (second screening) and at 12 and 36 months. Moreover, changes in
physical fitness and cardiovascular risk profile will be measured. In addition,
data on self-reported physical activity, dietary behaviour, motivational
factors, quality of life and other measures will be collected using structured
interviews. Furthermore, each patient will be asked to report the direct costs,
including for example the costs of transportation and the purchase of sports
gear. The direct non-medical costs, the indirect costs and the time investment
of professionals in the programme will also be determined.

The lifestyle intervention consists of 6-8 sessions of individual dietary
counselling based on motivational interviewing, supplemented with 1-2 home
visits, and 2 optional group sessions aimed at the social environment.
Moreover, participants will take part in a supervised exercise programme
consisting of 20 weekly sessions. The content of the intervention has been
adjusted to reflect prevalent dietary behaviours (e.g. irregular meal pattern),
physical activity preferences (e.g. fitness and dancing), motivational factors
(e.g. sessions to decrease the (perceived) social pressure) and barriers (e.g.
women-only facilities).
After completion of the initial stages of the intervention, participants will
receive 3 monthly follow up by telephone and 2 follow up contacts with the
dietician.

In the control group a lifestyle counsellor will provide the participants in
simple, personalised lifestyle advice. This advice is personalised in the sense
that, depending on the characteristics of the participant, the advice will
focus on one or more of the following aspects: overweight, physical exercise,
diet. The content advice itself will be generic.

Participants will be asked to participate in a screening and, if applicable, a
second screening (baseline measurement for the trial) to confirm the presence
of prediabetes.
The lifestyle intervention among persons with confirmed prediabetes consists of
individual dietary counselling (6-8 sessions, 2 home visits and 2 optional
sessions) and a supervised exercise programme (20 sessions). Follow-up
measurements are planned at 12 and 36 months.
During the all measurements (maximum of 4 measurement during the entire trial)
participants will be asked to participate in an interview varying in duraton
between 10-45 minutes, a physical examination and an oral glucose tolerance
test (OGTT). During the OGTT a venous blood sample will be taken before and
after 2 hours. No other invasive measurements are planned.