Web-based cognitive behavioural therapy (W-CBT) for diabetes patients with co-morbid depression: design of a randomised controlled trial [ISRCTN24874457]


Study Design
We chose a two-arm randomised controlled trial (RCT) design; including 286 patients (143/143). Measurements are scheduled at six points in time in the intervention group: at baseline, directly after completing the web-based intervention, and at 1, 3, 4 and 6 months follow-up. In the control group the same six measurements are scheduled with two additional measurements at 8 and 12 weeks after randomization. 

Study procedures
The recruitment and screening procedure has been developed, so that patients interested in joining the study can visit the research website. There, the patient will be invited to read the study information and provide written informed consent. After receipt of the consent form, the patient will receive a password per e-mail allowing him/her to log in and complete the online screening questions. For the baseline measurement, patients are invited to fill out a booklet of questionnaires on the Internet, -which will take approximately 30 minutes- containing demographic data, in – and exclusion criteria, and depressive symptoms (Center for Epidemiological Studies Depression scale (CES-D) >16) [22]. If a patient does not qualify, this is explained and the patient is advised to contact his/her GP for further advice. If eligible, the patient will be interviewed by telephone using the Composite International Diagnostic Interview (CIDI). Data from this CIDI interview will be used to specify type of mood disorder (DSM-IV). Those with bipolar disorder, depression with psychotic features and patients who suffer from current suicidal ideation will be excluded. After eligibility is confirmed the patient is enrolled in the study. 

Treatment allocation

Randomisation by computer will assign individual patients to either the experimental or control condition. 


The on-line depression course will be delivered through a website. The study will be advertised in the Netherlands and Flanders (Dutch speaking part of Belgium) in clinics (e.g. hospitals, GP’s, pharmacy’s, rehabilitation centres) and through various media (e.g. patient journals, specialist journals, websites, e-mails, flyers, newspapers etc.). It will be advertised as a web-based course for persons with diabetes (type 1 or type 2) to help improve a depressed mood. Patient information on the study will be available on the research website. Inclusion and exclusion criteria will be stated clearly on this website. 

Study population
The source population consists of adult diabetes patients with co-morbid depression. Blinding of subjects will -due to ethical reasons- not be carried out.

Inclusion criteria are: ≥18 years of age; having type 1 or type 2 diabetes (diagnosed > 3 months prior to study by a physician); having a depressed mood, as indicated by a score of 16 or higher on the Center for Epidemiological Studies Depression scale (CES-D); depression diagnosed by the CIDI-interview; having access to the Internet at home and having an e-mail address.

Exclusion criteria are: not having easy access to the Internet, reading problems (e.g. due to insufficient Dutch language skills, visual impairments or illiteracy); currently taking anti-depressant medication; a history of suicide attempt(s); current suicidal ideation (measured with the CIDI); bipolar disorder (CIDI); co-morbid organic psychiatric disorder (CIDI); loss of significant other < previous 6 months; or pregnancy. 

Description of interventions
Intervention group

Patient enrolment will occur individually on a continuous basis, i.e. at any point in time during the study period. The number of included participants is not limited by physical capacity other than the number of coaches available. After inclusion criteria are met and the patient has returned the informed consent s/he will be randomly assigned to the intervention or the control group.
Patients assigned to the intervention group will receive a password per e-mail with which they can log in to the course. They will be instructed (and reminded per e-mail) to complete one session per week, during 8 consecutive weeks.
Coaches will send e-mails to participants as a way to encourage them to continue their efforts. Such reinforcement should help to keep patients on track with the course and lower the risk of drop-out. They also provide the participants with feedback on their homework assignments. It is clearly stated that coaches will not give advice on personal issues.
Control group
Control group patients will receive an e-mail in which they are informed of the randomisation result, which means they will start the course after 12 weeks. To reduce the risk of loss of interest; participants placed on the waiting-list will automatically receive weekly protocollised e-mails with motivating, positive feedback to enforce them to remain involved in the study.
After eight weeks they are invited per e-mail to fill in the questionnaires again. Twelve weeks after randomization patients will undergo a second screening (using the CES-D-score ≥ 16 as a first screener for depression and additionally the CIDI interview) to confirm depression. If still eligible, the patient is invited to follow the course. Patients, who do not qualify, i.e. show (spontaneous) remission, are excluded at this point. Patients who developed suicidal ideation during the 12 weeks waiting period, are offered the opportunity to have an appointment with a diabetes psychologist of the VU University Medical Centre or a colleague nearby in case the distance from the participant’s home to the VUMC should be problematic.
The effectiveness of the intervention is determined directly after completing the web-based intervention up till 6 months follow-up (see Consort flow chart in figure 1).

If the depression has deteriorated at the end of the course, as indicated by the scores of the CES-D, a consultation with a diabetes psychologist at the VU Medical Centre is offered to the patient. In agreement with their General Practitioner a decision will be made about further treatment or hospitalization. 

Intervention development and trial design
The Dutch version of the manual-based self-help course named ‘Coping with Depression’ (‘In de put, uit de put’) has been adapted as web-based intervention (‘Kleur je Leven’) [23,24]. This intervention has been adjusted further by our team to fit the needs of patients with diabetes (‘Diabetergestemd’). Based on our research, clinical experience and input from an expert panel of diabetes patients, the following topics were incorporated: managing ‘poor’ test results, uncertainty about blood glucose fluctuations and negative emotions, communication with health care professionals, talking about diabetes with others, the burden of daily self-management, and coping with diabetes-related worries (e.g. about hypoglycaemia and late complications).The course consists of 8 consecutive weekly lessons. The course will provide information, practice examples, exercises/self-tests and homework assignments. The web-based course is delivered on an individual basis. Patients weekly receive (protocollized) feedback on their homework assignments from their coaches by e-mail. The coaches are psychologists and residents in clinical psychology from the department of Medical Psychology of the VU medical centre, supervised by the research team. An internet-based group forum, which will be moderated by our team, is offered to participants to give them the opportunity to share experiences, provide support and discuss issues related to depression and diabetes [25]. In the forum, specific treatment issues (e.g. related to oral medication or insulin) may not apply to all participants, but this should not be problematic. Rather, the mix of disease types and experiences can serve to illustrate the common features of diabetes and depression (thoughts, emotions and behaviors), while respecting individual differences.
It will be clearly stated that during the course of the study, all participants are allowed to make use of additional mental health care services if they feel a need to do so. 

22. Schroevers MJ, Sanderman R, van Sonderen E, Ranchor AV: The evaluation of the Center for Epidemiologic Studies Depression (CES-D) scale: Depressed and Positive Affect in cancer patients and healthy reference subjects. Qual Life Res 2000, 9: 1015-1029.
23. Cuijpers P: A psychoeducational approach to the treatment of depression: A meta-analysis of lewinsohn's "coping with depression" course. Behavior Therapy 1998, 29: 521-533.
24. Lewinsohn PM, Munoz R.F., Youngren M.A., Zeiss A.M., Cuijpers P: In de put, uit de put. Zelf depressiviteit overwinnen. Intro: Baarn; 1995.