Collaborative care for comorbid depression: cost-effectiveness and implementation

Collaborative care (CC) is a care model for patients with comorbid depression and chronic disease in which a care manager (CM) trained in the treatment of depression is the main regular point of contact for the patient, and facilitates the medical and psychiatric care specified and prescribed by the physician and psychiatrist, respectively. CC may be provided in a primary care or general hospital setting, but little is known about its cost-effectiveness and its impact on treatment outcomes. These issues have been addressed by researchers in the Netherlands and were presented at a lively symposium at APA 2018, followed by an inspiring presentation on how best to implement CC.

Collaborative care improves treatment outcomes and depression compared to care as usual (CAU)  

Cees Rijnders of Tilburg University, The Netherlands, presented the results of a recently published systematic review and meta-analysis investigating CC for comorbid depression and chronic disease. 1 The results of 20 randomized controlled trials (RCTs) involving 4774 patients were analysed.

CC was more effective than CAU but the effect size was small

CC was shown to be more effective than CAU in both primary care and general hospital settings for reducing illness burden and improving treatment outcomes and depression. However, the effect size was small (d = 0.27 for illness burden; d = 0.21 for combined treatment outcomes).

The best treatment outcomes were for hypertension, followed by HIV, chronic obstructive pulmonary disease (COPD), multimorbidity, arthritis, cancer and acute coronary syndrome.

More research covering multiple medical conditions with more personalized treatment models and a focus on self-management are needed to provide better estimates of effect size – and larger effects – for specific chronic medical conditions, Dr Rijnders concluded.

CC in a general hospital setting is more cost-effective than CAU

CC is more costly but also more effective than CAU

Christina Van der Feltz, Professor of Psychiatry and Epidemiology, University of York, UK, and previous Chair for GGZ Breburg, Tilburg, The Netherlands, presented a recently published RCT analyzing the cost-utility of CC for treating patients with comorbid MDD and chronic somatic conditions in the general hospital outpatient setting.2

Eighty-one patients with moderate-to-severe MDD and comorbid diabetes mellitus, COPD or cerebrovascular disease were included in the study and randomized to receive either CC or CAU for 12 weeks. In the CC group, the CM was a consultant psychiatric nurse (CPN), and patients were followed up every 3 months for 1 year.

The incremental cost-effectiveness ratio was €24,690/QALY from a societal perspective

Quality of life improved significantly for the CC group over time, and also improved for the CAU groups. The average quality-adjusted life years (QALYs) gained was 0.07 higher in the CC group compared with the CAU group, but the direct medical costs were higher for the CC group.

The resulting incremental cost-effectiveness ratio (ICER) was €28,366/QALY from a healthcare perspective and €24,690/QALY from a societal perspective. The Dutch Council for Public and Health Care maximum ICER threshold for acceptability of treatment is €80,000/QALY, explained Professor Van der Feltz.

Hospital admissions for the chronic somatic conditions – mainly arising from a relatively small group of patients – were responsible for the largest part of the costs for both CC and CAU groups and were higher for the CC group.

No significant difference was seen between the CC and CAU groups in terms of total remission and treatment response in terms of depressive symptoms measured by the Patient Health Questionnaire-9 (PHQ-9).

The number of adverse events was significantly less in the CC group, and this may have contributed to the improved quality of life despite the continued depressive symptoms, said Professor Van der Feltz.

She concluded that further research is needed to improve the cost-effectiveness of CC for patients with comorbid MDD.

Strategies for implementing CC

Liaison makes or breaks CC

Anna Ratzliff, Associate Professor of Psychiatry and Director of the Integrated Care Training Program at the University of Washington provides training on the implementation of CC. She explained that the five core principles for the successful implementation of CC are population-based care, measurement-based treatment to target, patient-centered collaboration, evidence-based care, and accountable care. She advocated:

  • training staff to screen patients using the PHQ-9 and other validated tools
  • repeated measurement to monitor patient progress and identify and prevent relapse
  • setting up a registry to keep track of all interventions and outcomes
  • the Plan-Do-Study-Act strategy with short cycles enabling early feedback for quality improvement (QI)
  • weekly reviews of the caseload enabling case-based learning
  • Professor Ratzliff also emphasized the importance of liaison with the PCP and CM, learning by integrating education into clinical care and direct teaching, and leadership through implementation and continuous QI to drive practice change.


1. van Eck van der Sluijs J et al. General Hospital Psychiatry 2018;50:1–14.

2. Goorden M et al. Neuropsychiatric Disease and Treatment 2017:13;1881–93.