Elsevier

The Lancet

Volume 363, Issue 9421, 15 May 2004, Pages 1589-1597
The Lancet

Articles
Systematic review and meta-analysis of randomised controlled trials of psychological interventions to improve glycaemic control in patients with type 2 diabetes

https://doi.org/10.1016/S0140-6736(04)16202-8Get rights and content

Summary

Background

Adherence difficulties and psychological problems are associated with poor glycaemic control in diabetes. We undertook a systematic review and meta-analysis of psychological therapies to assess their effectiveness in improving glycaemic control in type 2 diabetes.

Methods

We searched MEDLINE, PsychINFO, EMBASE, and the Cochrane Central Register of Controlled Trials up to January, 2003. Eligible studies were randomised controlled trials that involved people with type 2 diabetes and evaluated a psychological therapy (counselling, cognitive behaviour therapy, or psychodynamic therapy) to improve diabetes control. We extracted the number of participants, their age, duration of diabetes, glycaemic control, type of psychological therapy, its mode of delivery, and type of intervention in the control group. The main outcome was long-term glycaemic control measured by percentage of glycated haemoglobin. Blood glucose concentration, weight, and psychological distress were also measured. Pooled standardised effect sizes were calculated.

Findings

25 trials were eligible for the review. In 12 trials, the mean percentage glycated haemoglobin was lower in people assigned a psychological intervention than in the control group (usual care, education, waiting list, or attention control); the pooled mean difference was -0·32 (95% CI -0·57 to -0·07) equivalent to an absolute difference of -0·76%. There were non-significant differences in blood glucose concentration (eight trials; -0·11 [-0·65 to 0·42]) and weight gain (nine trials; 0·37 [-0·18 to 0·93]). Psychological distress was significantly lower in the intervention groups (five trials; −0·58 [−0·95 to −0·20]).

Interpretation

In type 2 diabetes, there are improvements in long-term glycaemic control and psychological distress but not in weight control or blood glucose concentration in people who receive psychological therapies.

Introduction

People with type 2 diabetes have to adhere to many self-care responsibilities to achieve optimum glycaemic control. The tasks include: modification of lifestyle, such as diet, exercise, and weight; self-monitoring of blood glucose concentrations; foot care; and administration of oral medication and, increasingly, insulin injections. Difficulties in adhering to these tasks can be associated with suboptimum glycaemic control even in the most intensively managed groups.1 Psychological problems such as depressive disorders2, 3, 4 and eating disorders5, 6 are common and are associated with suboptimum glycaemic control7 and diabetes complications.8

Previous systematic reviews of non-pharmacological interventions did not adequately distinguish between educational and psychological interventions, between type 1 and type 2 diabetes, or between randomised and non-randomised trials.9, 10, 11, 12, 13 The distinction between education and psychological therapy is clinically important because they differ (but are not mutually exclusive) in their theoretical basis, training, clinical skills, and implications for resources. Educational interventions are based on didactic and enhanced learning methods which aim to improve diabetes self-management by increasing knowledge. Psychological therapies use the therapeutic alliance between the patient and the therapist to bring about change in emotional, cognitive, and behavioural functioning, including adherence.14

In view of the rising prevalence of type 2 diabetes,15 a potential limit to pharmacological interventions,1 and effectiveness of psychological therapies for depression16 and eating disorders,17 more sophisticated non-pharmacological approaches are needed. Our aims were to carry out a systematic review and meta-analysis of randomised controlled trials assessing the effectiveness of psychological therapies in improving glycaemic control in adults with type 2 diabetes and in reducing psychological distress and bodyweight.

Section snippets

Criteria for selecting studies

The protocol was peer reviewed and published in the Cochrane Database of Systematic Reviews.18 We followed the QUORUM guidelines.19

Studies eligible for inclusion were randomised controlled trials of a psychological intervention, published or unpublished, involving adult (18 years and older) patients with a diagnosis of type 2 or non-insulin-dependent diabetes. We classified the type of psychological intervention into psychotherapeutic models most commonly used in health-care settings. These

Results

The search strategy identified 2427 studies from which 93 full texts were selected for further extraction (figure 1). There was 89·6% agreement as to which abstracts from the electronic databases to select for retrieval of full texts (k=0·64). Data extraction from the full texts identified 25 randomised controlled trials that met the criteria for the systematic review. Reasons for exclusion from the review and meta-analysis are shown in figure 1.

The studies included in the systematic review are

Discussion

We identified 25 randomised controlled trials comparing psychological interventions for improving control of diabetes with a control group of usual care, education, waiting list, or attention control. In a meta-analysis of 12 of these trials, psychological therapies resulted in significantly better glycaemic control approximating to an absolute difference of 0·76% in glycated haemoglobin. When studies that used a less intensive psychological therapy as a comparison were excluded, the pooled

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