Review
Preventing the progression to Type 2 diabetes mellitus in adults at high risk: A systematic review and network meta-analysis of lifestyle, pharmacological and surgical interventions

https://doi.org/10.1016/j.diabres.2015.01.027Get rights and content

Highlights

  • We review interventions for the prevention of Type 2 diabetes mellitus.

  • We perform a network meta-analysis.

  • Pharmacological interventions may be more beneficial than lifestyle interventions.

Abstract

Aims

Individuals with impaired fasting glucose (IFG) or impaired glucose tolerance (IGT) have an increased risk of progression to Type 2 diabetes mellitus. The objective of this review was to quantify the effectiveness of lifestyle, pharmacological and surgical interventions in reducing the progression to Type 2 diabetes mellitus in people with IFG or IGT.

Methods

A systematic review was carried out. A network meta-analysis (NMA) of log-hazard ratios was performed. Results are presented as hazard ratios and the probabilities of treatment rankings.

Results

30 studies were included in the NMA. There was a reduced hazard of progression to Type 2 diabetes mellitus associated with all interventions versus standard lifestyle advice; glipizide, diet plus pioglitazone, diet plus exercise plus metformin plus rosiglitazone, diet plus exercise plus orlistat, diet plus exercise plus pedometer, rosiglitazone, orlistat and diet plus exercise plus voglibose produced the greatest effects.

Conclusions

Lifestyle and some pharmacological interventions are beneficial in reducing the risk of progression to Type 2 diabetes mellitus. Lifestyle interventions require significant behaviour changes that may be achieved through incentives such as the use of pedometers. Adverse events and cost of pharmacological interventions should be taken into account when considering potential risks and benefits.

Introduction

Type 2 diabetes mellitus is associated with significant clinical and social consequences, including a reduced quality of life and a reduction in life expectancy of up to 10 years. It has a long preclinical phase and 30–50% of all individuals with diabetes can remain undiagnosed for many years [1]. Diabetes accounts for approximately 10% of UK health expenditure but is projected to rise to 17% by 2035/2036 [2]. Conditions defined by blood glucose levels between normal and that associated with Type 2 diabetes mellitus are typically known as impaired fasting glucose (IFG) or impaired glucose tolerance (IGT). Individuals with IFG or IGT have an increased risk of progression to Type 2 diabetes mellitus but this is not inevitable and progression rates vary in different populations.

Risk factors for individuals at high risk of developing Type 2 diabetes mellitus include obesity, a high waist circumference, a sedentary lifestyle, a close family history of Type 2 diabetes mellitus, a history of gestational diabetes in women, being older than 40 years of age, and being of South Asian, African-Caribbean and black African descent. Lifestyle changes, including improved diet and increased physical activity levels, pharmacological interventions [3] and bariatric surgery have all been demonstrated to have utility in preventing the progression to Type 2 diabetes mellitus in those people at high risk. A recent systematic review confirms the growing evidence base from individual studies that diet and exercise interventions can be effective if significant behaviour change is achieved [4] but it is still necessary to understand the relative value of lifestyle intervention and/or drug treatment.

The objective of this systematic review was to quantify the effectiveness of lifestyle, pharmacological and surgical interventions in reducing the progression to Type 2 diabetes mellitus in people with IFG or IGT using a network meta-analysis [5].

Section snippets

Search strategy

The search strategy for this systematic review was based on an earlier search strategy used by Gillies et al. [3] but with some modification to ensure a balance between sensitivity and specificity as outlined in the NICE Public Health Reviews Methods Manual [6]. The search strategy combined terms for the presentation of Type 2 diabetes mellitus and terms relating to pre-diabetes with a randomised control trials filter. This approach was adopted to ensure that no intervention intended for the

Study characteristics

A Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flow diagram is presented in Fig. 1.

No randomised controlled trials assessing the effect of surgical interventions were identified that met the inclusion and exclusion criteria.

The initial review carried out by Gillies et al. [3] identified 21 studies that met the inclusion criteria, although four of those studies were excluded from that meta-analysis because the studies reported insufficient data. Three of the

Discussion

This review updates and extends a previous review of the effects of lifestyle and pharmacological interventions on progression to Type 2 diabetes mellitus in people with IFG or IGT [3]. It differs from the original review in several ways.

Data from sixteen additional studies were included; three foreign language studies were excluded; additional follow-up data from extension studies was included; and ten additional interventions were assessed. Gillies et al. [3] made a subjective comparison

Conflict of interest statement

KK (chair) and MJD are members of the National Institute for Health and Clinical Excellence public health guidance on preventing type 2 diabetes and both are advisers to the UK Department of Health for the NHS health checks programme. No other author has any conflicts of interest.

Funding

This review is an update of an earlier review that was commissioned by the Centre for Public Health Excellence of behalf of the National Institute for Health and Clinical Excellence (NICE).

Acknowledgements

We would like to thank Clare Gillies for providing us with the data from the earlier review that was published in the British Medical Journal; Roy Jones and Crystal Freeman for providing systematic review support; Nick Payne for providing clinical expertise; and Emma Everson-Hock for double checking the updated review. We acknowledge support from the National Institute for Health Research Collaboration for Leadership in Applied Health Research and Care – East Midlands (NIHR CLAHRC – EM), the

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