Psychological Therapy to Improve Control of Type 1 Diabetes

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The summary below is from the full report titled "Motivational Enhancement Therapy with and without Cognitive Behavior Therapy to Treat Type 1 Diabetes. A Randomized Trial." It is in the 18 November 2008 issue of Annals of Internal Medicine (volume 149, pages 708-719). The authors are K. Ismail, S.M. Thomas, E. Maissi, T. Chalder, U. Schmidt, J. Bartlett, A. Patel, C.M. Dickens, F. Creed, and J. Treasure.

What is the problem and what is known about it so far?

Type 1 diabetes mellitus (also called childhood diabetes) occurs when the pancreas stops making insulin. Insulin helps the body use the energy that foods provide. Without insulin, blood sugar levels become high. Over time, high blood sugar levels can lead to blindness, kidney failure, damage to nerves, and heart disease. To keep blood sugar levels in the normal range, people with type 1 diabetes must inject insulin and monitor their diet and exercise. Psychological issues can interfere with a patient's ability and confidence to manage their diabetes, and it is possible that psychological treatments could improve diabetes control.

Why did the researchers do this particular study?

To find out whether psychological therapy can improve blood sugar control for patients with type 1 diabetes. They were interested in 2 types of therapy: motivational enhancement therapy and cognitive behavior therapy. Motivational enhancement therapy is brief therapy (1 to 4 sessions) during which the therapist counsels the patient to motivate him or her to follow healthy behaviors. Cognitive behavior therapy is longer therapy (6 to 12 sessions) that tries to help patients identify unhelpful behaviors and replace them with more helpful ones. They were also interested to find out if diabetes nurses could be trained to deliver these psychological treatments because it is not always possible to access a psychologist.

Who was studied?

344 adults with type 1 diabetes at 8 diabetes centers in the United Kingdom. To be in the study, patients had to have had diabetes for at last 2 years, a hemoglobin A_1c (HbA_1c) level of 8.2% to 15%, and no complications of diabetes or other severe medical conditions. Hemoglobin A_1c is a blood test that measures sugar control over the past 3 months. In most cases, doctors and patients should aim for an HbA_1c level less than 7%.

How was the study done?

The researchers assigned patients to receive either motivational enhancement therapy, motivational enhancement therapy plus cognitive behavior therapy, or usual care. Trained nurses provided the psychological therapies. Patients who received motivational enhancement therapy had 4 sessions over 2 months. Patients who received cognitive behavior therapy had 12 sessions over 6 months. The researchers then collected information on change in HbA_1c levels over 12 months, low blood sugar episodes, depression, quality of life, diabetes self-care activities, and weight.

What did the researchers find?

Patients who received both psychological therapies had a greater decrease in HbA_1c levels than patients who received usual care. Patients who received only motivational enhancement therapy did not have better blood sugar control than patients who received usual care. None of the other outcomes differed among the 3 groups.

What were the limitations of the study?

No patient received only cognitive behavior therapy, so this study was unable to determine the effect of cognitive behavior therapy alone. Also, about 11% of the patients did not return for HbA_1c measurements at 12-month follow-up. In addition, patients had HbA_1c levels of 8.6% to 10.3% at the start of the study and no diabetes complications. It is possible that psychological therapies could have more benefit in patients who had worse diabetes control.

What are the implications of the study?

Combined psychological therapies (motivational enhancement therapy plus cognitive behavior therapy) resulted in clinically relevant improvements in blood sugar control in type 1 diabetes compared with usual care.