Should we limit collaborative care for depression to those with chronic medical conditions? Results from an individual patient data meta-analysis

Problem

The combination of a long term condition and depression is associated with the greatest decrements in quality of life, increased mortality, threats to patient safety, and unscheduled care, with significant cost implications. Collaborative care is an enhanced care model that has proven effective for managing depression, including depression in people with long term conditions. In England the National Institute for Health and Care Excellence recommend that collaborative care be only provided for people with depression and long term conditions. However this guidance is based on old study level aggregate evidence and there is a case for using individual patient data meta-analysis to model treatment effects to better inform future clinical guidance.

Approach

One-step meta-analysis of individual patient data from randomised controlled trials of collaborative care in primary care and community settings. Main outcome measures were the moderating effect of the presence, number, and types of long-term conditions on depression severity.

Findings

Datasets from 32 randomised controlled trials including 37 independent comparisons (n= 10,962 participants with depression) were collated. At study level, trials which explicitly identified patients with chronic medical conditions produced larger treatment effects compared to trials which did not explicitly identify patients with chronic medical conditions (interaction coefficient -0.13, 95% CI= -0.23 to – 0.02). However, results of study level analyses may be driven by other unknown patient or study characteristics. Only patient level analyses can rigorously test whether the treatment effect is influenced by patient characteristics such as chronic medical conditions. Indeed, when individual patient data analyses were performed, no significant interaction effects were found indicating that the presence, numbers and types of chronic medical conditions do not influence the treatment effect of collaborative care.

Consequences

This study produced compelling evidence that collaborative care is effective for all patients with depression including those with comorbid chronic medical conditions and those without. Limiting collaborative care for people with depression and chronic medical conditions is not supported by these findings. Meta-analysis of individual patient data was necessary to determine the impact of chronic medical conditions on the effectiveness of collaborative care for depression.