Are effects of depression management training for General Practitioners on patient outcomes mediated by improvements in the process of care?

BACKGROUND Depression treatment by General Practitioners (GPs) and patient outcomes improved significantly after a comprehensive 20-h training program of GPs. This study examines whether the effects on patient outcomes are caused by the improvements in the process of care. METHODS Seventeen GPs participated in the training program. A pre-test-post-test design was used. A total of 174 patients (85 pre-test, 89 post-test) aged 18-65 met ICD-10 criteria for recent onset major depression. The main indicator of mediation was a drop in training effect size (eta2) on patient outcome after adjustment for individual and combined process of care variables. We evaluated depression-specific (recognition, accurate diagnosis, prescription of antidepressant, adequate antidepressant treatment) and a non-specific process of care variable (communicative skillfulness of the GP) as well as the combination of adequate antidepressant treatment and communicative skillfulness. Patient outcomes were assessed at 3 months and consisted of change in severity of symptomatology, level of daily functioning and activity limitation days from baseline. RESULTS Depression-specific interventions mediated up to one third of the observed improvement in patient outcome. 'Adequate dosage and duration of an antidepressant' explained 36% of the training effect on patient outcome (eta2 from 0.044 to 0.028). 'Communicative skillfulness of the GP' only was a weak mediator (18% explained; eta2 from 0.044 to 0.036). However, the combination of both, that is adequate antidepressant treatment by a communicative skillful GP, proved to be the strongest mediator of the observed training effect on patient outcomes (59% explained; eta2 from 0.044 to 0.018). LIMITATIONS The training effects on patient outcomes in this sample were small. Hence, the scope for mediation was limited. CONCLUSION GP communication skills are important to enhance depression-specific interventions in bringing about improvements in patient outcomes and should be addressed in GP training programs for the treatment of depression.