Persistence in the long term of the effects of a collaborative care programme for depression in primary care

Abstract

Background: A collaborative care programme for depression in primary care has proven clinical effectiveness over a 12-months period. Because depression tends to relapse and to chronic course, our aim was to determine whether the effectiveness observed in the first year persists during 3 years of monitoring.

Methods: Randomised controlled trial with twenty primary care centres were allocated to intervention group or usual care group. The intervention consisted of a collaborative care programme with clinical, educational and organisational procedures. Outcomes were monitored by a blinded interviewer at baseline, 12 and 36 months. Clinical outcomes were response to treatment and remission rates, depression severity and health-related quality of life.

Trial registration: ISRCTN16384353.

Results: A total of 338 adult patients with major depression (DSM-IV) were assessed at baseline. At 36 months, 137 patients in the intervention group and 97 in the control group were assessed (attrition 31%). The severity of depression (mean Patient Health Questionnaire-9 score) was 0.95 points lower in the intervention group [6.31 versus 7.25; p=0.324]. The treatment response rate was 5.6% higher in the intervention group than in the control group [66.4% versus 60.8%; p=0.379] and the remission rate was 9.2% higher [57.7% versus 48.5%; p=0.164]. No difference reached statistical significance.

Limitations: The number of patients lost (31%) before follow-up may have introduced a bias.

Conclusions: Clinical benefits shown in the first year were not maintained beyond: at 36 months the differences between the control group and the intervention group reduced in all the analysed variables.

Keywords: Collaborative care; Controlled clinical trial; Depression; Disease management; Primary health care.