Practice nurse-led structured care of adult patients with chronic or recurrent depression achieved a modest improvement in functional impairment but did not significantly improve depression scores or quality of life, a randomised controlled trial has found.

The ProCEED (proactive care and its evaluation for enduring depression) trial recruited participants from 42 general practices throughout the UK. Recurrent depression was defined as two or more documented episodes of major depression within the previous three years. Chronic depression was defined as an episode of major depression lasting at least two years.

Overall, 276 patients were allocated to the control group (GP treatment as usual) and 282 to the proactive care intervention. This was provided by practice nurses who received three days’ training which included basic training in problem-solving techniques. Ten follow-up appointments were provided over a two-year period in the intervention group.

The intervention was a form of case management i.e. proactive contact with patients structured around medication concordance, adjustment of treatment plans and guided self-help.

At 24 months, there was no significant difference between the mean Beck Depression Inventory (BDI-II) scores for the intervention and control groups. There are two possible explanations: either the intervention was ineffective or not enough patients fully participated in the intervention sessions. A contamination-adjusted intention to treat analysis¹ was used to adjust for non-adherence.

This showed an impact per practice nurse intervention session of -0.37 (95% CI: -0.68 to -0.07) on the BDI-II score suggesting a mean BDI-II score reduction of 3.7 for those attending all ten intervention sessions.

At 24 months, there was no significant difference between the mean quality of life scores, but there was a significant difference in the functional impairment scores favouring the intervention group (Work and Social Adjustment Scale (WSAS) mean score difference of 2.5 (95% CI: 0.6-4.3).

Even if the contamination-adjusted analysis is valid, it is doubtful that a reduction in the BDI-II score of 3.7 is enough for the participants to have felt some improvement. A recent analysis of three randomised, controlled trials suggests that the minimum score reduction which will be perceived by the patient varies according to the baseline score and is greater for those with chronic depression.2 For the ProCEED trial participants I calculate the minimum clinically important score reduction to be 10.2.

The WSAS asks patients to rate their level of functional impairment in five domains: work, home management, private leisure, social leisure and family relationships. The possible score ranges from 0 to 40; scores of 10-20 indicate significant functional impairment and scores > 20 indicate at least moderately severe functional impairment.³ Again, it is questionable whether the mean score difference of 2.5 represents a clinically significant improvement in functioning.

These results are disappointing but perhaps not unexpected. Case management can improve outcomes for depressed patients through improved medication adherence,⁴ but this is unlikely to be sufficient for those with chronic or recurrent depression. Collaborative care (case management plus involvement of at least one other professional, use of an evidence-based protocol and enhanced liaison with secondary care) can improve outcomes in chronic depression⁵ but is expensive. The results are better when case managers have a mental health background.⁶ The authors of the present study acknowledge that their practice nurses had varying levels of confidence in managing mental health issues⁷ and that the intervention was limited by poor access to timely psychological treatment.

I will continue to promote nurse-led case management as an effective form of enhanced care for patients with new onset depression.

However, those with chronic or recurrent depression are only likely to benefit from a more complex collaborative care intervention which is currently unavailable in most UK primary care settings.

Dr Phillip Bland