Plain English Summary
Background and study aims
Non-response is an important issue for studies using a written questionnaire. For different reasons, potential participants are reluctant to complete questionnaires. Our aim is to find the best possible level of incentive (when using a written questionnaire and additional telephone interview) to participate in a study.
Who can participate?
Patients with diabetes who are aged 18 years or over can participate in this study.
What does the study involve?
Patients are randomly allocated to one of four groups. Patients are offered four different levels of incentive (either 5, 7.50, 10 or 12.50 euros, according to the group that they are allocated to) to participate in a written survey and an additional telephone interview.
What are the possible benefits and risks of participating?
All patients are part of the study, even if they do not participate (as we are studying the participation rate). The benefit for those who do participate is a gift card with a value of between 5 and 12.50 euros. There are no risks involved.
Where is the study run from?
This study is run from 7 GP practices; 5 of them in the city of Arnhem and 2 in the region Achterhoek (including the towns Aalten and Gendringen), Netherlands.
When is study starting and how long is it expected to run for?
Recruitment of patients started in June 2013 and will last until August 2014.
Who is funding the study?
The study is funded by the European Union, Belgium.
Who is the main contact?
Mr Jan Koetsenruijter, j.koetsenruijter@iq.umcn.nl
Professor Michel Wensing, m.wensing@iq.umcn.nl
Trial website
Additional identifiers
EudraCT number
ClinicalTrials.gov number
Protocol/serial number
N/A
Study information
Scientific title
The effect of different incentive levels on the participation rate for a mailed survey and telephone interview: a randomized controlled trial
Acronym
Study hypothesis
Higher incentives will lead to a higher response rate, but this effect is not linear. For example, the relative increase of response will become smaller as the incentive becomes higher. Moreover, we expect this curve to be different between high and low deprivation areas.
Ethics approval
Committee on Research Involving Human Subjects (CMO) region Arnhem - Nijmegen (Commissie Mensgebonden Onderzoek [CMO] regio Arnhem Nijmegen), 08/04/2013, ref: 2013/098
Study design
Randomized controlled trial
Primary study design
Interventional
Secondary study design
Randomised controlled trial
Trial setting
GP practices
Trial type
Screening
Patient information sheet
Not available in web format, please contact j.koetsenruijter@iq.umcn.nl to request a patient information sheet
Condition
Participation rate within patients with type 2 diabetes
Intervention
Patients are randomized within a GP practice. At the GP practice the patient is handed over an anonymous and closed envelope with a specific level of incentive and a questionnaire included. Both researcher and the employee at the GP practice do not know the level of the included incentive.
Respondents are offered four different levels of incentive to participate in a written survey and an additional telephone interview. The incentives are 5, 7.50, 10 and 12.50 euros. This is the only difference between the four treatment arms. There is no follow-up planned.
Intervention type
Other
Phase
Not Applicable
Drug names
Primary outcome measures
Participation rate will be studied within three different areas with different levels of deprivation (subgroup analysis). The participation rate is measured by the total amount of completed questionnaires and telephone interviews, divided by the total number of distributed questionnaires. This rate will be calculated for each level of incentive. There is only one time point as each participant can only complete the questionnaire once.
Secondary outcome measures
Not provided at time of registration
Overall trial start date
01/06/2013
Overall trial end date
01/08/2014
Reason abandoned
Eligibility
Participant inclusion criteria
1. Medical diagnosis of diabetes (not a patient-reported diagnosis)
2. Type 2 diabetes only (no type 1, but comorbidities such as cardiovascular disease are allowed)
3. Male and female, 18 years or over
Participant type
Patient
Age group
Adult
Gender
Both
Target number of participants
300
Participant exclusion criteria
1. No established diagnosis of diabetes, but obesity or high risk for developing diabetes
2. Mix of type 2 and type 1 (not pure type 2 diabetes)
3. Pregnancy
4. Pregnancy-related diabetes
5. Recent/current major surgery or medical procedures
6. Severe cognitive or psychiatric handicap
7. Terminal illness/receiving palliative care
8. Absence of translators (e.g. family members) for patients with insufficient language skills
Recruitment start date
01/06/2013
Recruitment end date
01/08/2014
Locations
Countries of recruitment
Netherlands
Trial participating centre
Geert Grooteplein 21
Nijmegen
6500 HB
Netherlands
Sponsor information
Organisation
Radboud University Medical Centre (Netherlands)
Sponsor details
Postbus 9101
Nijmegen
6500 HB
Netherlands
Sponsor type
Hospital/treatment centre
Website
Funders
Funder type
Government
Funder name
European Union (Belgium)
Alternative name(s)
Funding Body Type
Funding Body Subtype
Location
Results and Publications
Publication and dissemination plan
Not provided at time of registration
Intention to publish date
Participant level data
Not provided at time of registration
Results - basic reporting
Publication summary