Depression prevention in primary care: Stepped care for patients with type 2 diabetes and/or coronary heart disease.

Background:

Co-morbid depressive symptoms constitute a significant health problem among patients with type 2 diabetes mellitus (DM2) and/or coronary heart disease (CHD). Subthreshold depression is the most important risk factor for the development of major depression and negatively impacts quality of life. Given the highly significant association between depression and adverse health outcomes and the limited capacity for depression treatment in primary care, there is an urgent need for interventions to successfully prevent the transition from subthreshold depression into a major depressive disorder.



Objective:

To evaluate the cost-effectiveness of a nurse-led indicated stepped care program to prevent major depression among DM2 and/or CHD primary care patients with subthreshold depressive symptoms.



Methods:

An economic evaluation will be conducted alongside a cluster-randomized controlled trial in approximately thirty general practices in the Netherlands. Randomisation takes place at the level of participating practices. We aim to include 262 participants that will either receive a nurse-led indicated stepped care program for depression or care as usual. The stepped care program consists of four sequential but flexible treatment steps: 1) watchful waiting, 2) guided self-help treatment, 3) problem solving treatment and 4) referral to the general practitioner.

The primary clinical outcome is the cumulative incidence of major depressive disorder as measured with the Mini International Neuropsychiatric Interview (MINI). Secondary outcomes include quality of life, severity of depressive symptoms, anxiety and physical outcomes. Costs will be measured from a societal perspective and include health care utilization, medication and lost productivity costs. Measurements will be done at baseline, and 3, 6, 9 and 12 months.



Discussion:

The intervention being investigated is expected to prevent new cases of depression among people with DM2 and/or CHD and subtreshold depression, with subsequent beneficial effects on quality of life, clinical outcomes and health care costs. When proven cost-effective, the program provides a viable treatment option in the Dutch primary care system.

It is hypothesized that a flexible stepped care program for depression reduces the incidence of depression, severity of depression and anxiety symptoms and healthcare costs among primary care patients with diabetes type 2 and/or CHD and sub threshold depression. Also, it is expected that the flexible stepped care program will improve patient's quality of life significantly.

Measurements will be performed at baseline and at 3, 6, 9 and 12 months follow-up.

The intervention is modeled after the flexible stepped-care intervention by Van 't Veer-Tazelaar et. al. (2009) The nurse-led stepped-care program consists of four evidence-based treatment steps, lasting 3 months each. Participants who still have elevated depressive symptom levels after each treatment step are offered participation in the next step. A score below the cut off point results in a period of watchful waiting until an elevated PHQ-9 score indicates the need for the following step of the intervention.

By providing stepped care and offering more intensive treatment only to people still having elevated depressive symptom scores, it is expected that patients receive treatment that is tailored to their needs and that available resources are more efficiently used.

Patients who have major depression at baseline or at 3, 6, 9 or 12 months are referred directly to their GP by the practice nurse. The following treatment steps are offered to participants:


Step 1: Watchful waiting. The first 3 months consist of watchful waiting, because depressive symptoms often disappear spontaneously over time.



Step 2: Guided self-help. During this step, participants are offered a self-help course that is specially designed for patients with a chronic physical illness and depressive complaints (Cuijpers & van Osch, 2009).



Step 3: Problem-solving treatment. In this step, participants are offered Problem Solving Treatment (PST), which is a brief cognitive behavioural intervention that focuses on practical skill building. (Mynors-Wallis et.al., 1997).



Step 4: Referral to general practitioner (GP). Participants with continuously elevated PHQ-9 scores will be referred to their general practitioner.