Patients with type 2 diabetes have multiple responsibilities, including lifestyle modifications, dietary restrictions, self-monitoring of glucose levels, screening for complications, and adherence to medications. Depressive conditions, eating disorders, and other psychologic problems are common in patients with diabetes and are associated with poor glycemic control and an increase in complications. Psychologic therapies can influence emotional, cognitive, and behavioral function, including adherence to medical therapy, but their role in the management of type 2 diabetes is not completely understood and frequently is confused with the impact of patient education. Ismail and colleagues reviewed the evidence for effectiveness of psychologic therapies in improving glycemic control and reducing psychologic distress and body weight in patients with type 2 diabetes.
The authors reviewed several electronic databases to identify published and unpublished randomized controlled trials (RCTs) of any psychologic intervention in patients 18 years or older with type 2 diabetes. Abstracts of studies were reviewed independently by two researchers. The outcome measures were glycemic control as measured by A1C and/or blood glucose, body weight, and relevant measures of psychologic distress.
From 2,427 studies initially identified, 25 RCTs met criteria for inclusion in the review. Data from 12 studies with 522 patients could be pooled for change in A1C. Overall, the decrease in A1C was −0.32 compared with the control group. The effect was larger when two studies that used less intensive psychologic therapy were excluded. The effect was equivalent to a decrease of 1.06 percent in A1C. Five trials demonstrated a reduction in psychologic distress compared with control patients.
Conversely, studies did not show benefit in blood glucose concentrations or weight control. Data from eight studies could be pooled to assess the effect on blood glucose. The net difference was estimated to be 3.6 mg per dL (0.20 mmol per L), equivalent to no significant benefit in patients receiving psychologic therapy compared with control patients. The nine studies with data on weight showed a nonsignificant increase in weight; however, when an early outlying study was excluded, an overall negligible effect on weight was demonstrated.
The authors conclude that psychologic therapies can positively affect long-term glycemic control and psychologic symptoms but have limited or no effect on blood glucose or weight loss. They believe that psychologic therapies can be useful adjuncts in diabetes management, but more research is needed to clarify which subgroups of patients are most likely to benefit and how standard psychologic therapies may need to be adapted to the special needs of patients with diabetes.