Objective: To update a meta-analysis and determine the effectiveness of psychological interventions on glycaemic control measured by HbA(1c) and psychological status in type 2 diabetes and to compare effects when interventions are delivered by generalist clinicians compared to psychological specialists.
Methods: We used the original review protocol and searched the Cochrane central register of controlled trials, Medline, Embase, PsychLIT, and Google Scholar from February 2003 (end of previous review) to March 2007. We extracted data on the participants, interventions, delivery methods, comparison groups and outcome measures.
Results: 35 trials were reviewed and meta-analysis of 19 trials (n=1431), reporting HbA(1c) found a reduction in HbA(1c) by 0.54% (-0.32; 95% CI: -0.47 to -0.16). In nine trials (n=832) interventions were delivered by diabetes or general clinicians reducing HbA(1c) by 0.51% (-0.27; 95% CI: -0.50 to 0.04). In nine trials, interventions (n=561) were delivered by psychological specialists reducing HbA(1c) by 0.57% (-0.36; 95% CI: -0.61 to 0.12). Meta-analysis of 13 trials reporting psychological status found psychological status to be lower in the intervention groups -0.56 (95% CI: 1.00 to -0.13). Trial quality for the majority of studies remained poor.
Conclusion: Our findings suggest that psychological and general clinicians are similarly effective in delivering psychological interventions, however, effect sizes for all clinicians have reduced since the earlier review.
Practice implications: Psychological training opportunities for generalist clinicians could lead to wider availability of effective psychological care.