Effect of interventions for major depressive disorder and significant depressive symptoms in patients with diabetes mellitus: a systematic review and meta-analysis

Background: Comorbid depression in diabetes is highly prevalent, negatively impacting well-being and diabetes control. How depression in diabetes is best treated is unknown.

Objective: This systematic review and meta-analysis aims to establish the effectiveness of existing anti-depressant therapies in diabetes.

Data sources: PubMed, Psycinfo, Embase and Cochrane library. Study eligibility criteria, participants, interventions: randomized controlled trials (RCTs) evaluating the outcome of treatment by psychotherapy, pharmacotherapy or collaborative care of depression in persons with Type 1 and Type 2 diabetes mellitus.

Study appraisal: risk of bias assessment; data extraction. Synthesis methods: data synthesis, random model meta analysis and publication bias analysis.

Results: Meta analysis of 14 RCTs with a total of 1724 patients show that treatment is effective in terms of reduction of depressive symptoms: -0.512; 95% CI -0.633 to -0.390. The combined effect of all interventions on clinical impact is moderate, -0.370; 95% CI -0.470 to -0.271; it is large for psychotherapeutic interventions that are often combined with diabetes self management: -0.581; 95% CI -0.770 to -0.391, n=310 and moderate for pharmacological treatment: -0.467; 95% CI -0.665 to -0.270, n=281. Delivery of collaborative care, which provided a stepped care intervention with a choice of starting with psychotherapy or pharmacotherapy, to a primary care population, yielded an effect size of -0.292; 95% CI -0.429 to -0.155, n=1133; indicating the effect size that can be attained on a population scale. Pharmacotherapy and collaborative care aimed at and succeeded in the reduction of depressive symptoms but, apart from sertraline, had no effect on glycemic control.

Limitations: amongst others, the number of RCTs is small.

Conclusion: The treatment of depression in people with diabetes is a necessary step, but improvement of the general medical condition including glycemic control is likely to require simultaneous attention to both conditions. Further research is needed.