Prevention of type 2 diabetes in adults with impaired glucose tolerance: the European Diabetes Prevention RCT in Newcastle upon Tyne, UK

Abstract

Background: Diabetes prevalence is increasing. The Finnish Diabetes Prevention Study (DPS) showed a 58% reduction in Type 2 Diabetes (T2D) incidence in adults with impaired glucose tolerance (IGT). The European Diabetes Prevention Study (EDIPS) extends the DPS to different European populations, using the same study design. In the Newcastle arm of this study (EDIPS-Newcastle), we tested the hypothesis that T2D can be prevented by lifestyle intervention and explored secondary outcomes in relation to diabetes incidence.

Methods: We recruited 102 participants (42 men and 60 women, mean age 57 years, mean BMI 34 kgm-2) with IGT to EDIPS-Newcastle and randomised to Intervention and usual care Control groups. The intervention included individual motivational interviewing aimed at: weight reduction, increase in physical activity, fibre and carbohydrate intake and reduction of fat intake (secondary outcomes). The primary outcome was diagnosis of T2D.

Results: Mean duration of follow-up was 3.1 years. T2D was diagnosed in 16 participants (I = 5, C = 11). Absolute incidence of T2D was 32.7 per 1000 person-years in the Intervention-group and 67.1 per 1000 person-years in the Control-group. The overall incidence of diabetes was reduced by 55% in the Intervention-group, compared with the Control-group: RR 0.45 (95%CI 0.2 to 1.2).Explanatory survival analysis of secondary outcomes showed that those who sustained beneficial changes for two or more years reduced their risk of developing T2D.

Conclusion: Our results are consistent with other diabetes prevention trials. This study was designed as part of a larger study and although the sample size limits statistical significance, the results contribute to the evidence that T2D can be prevented by lifestyle changes in adults with IGT. In explanatory analysis small sustained beneficial changes in weight, physical activity or dietary factors were associated with reduction in T2D incidence.

Trial registration: International Standard Randomised Controlled Trial Number registry (ISRCTN) Registry number: ISRCTN15670600. (http://www.controlled-trials.com/isrctn/search.html?srch=15670600&sort=3&dir=desc&max=10).

Figure 1

Flow of participants during recruitment to EDIPS-Newcastle.

Figure 2

Flow of participants through EDIPS-Newcastle RCT. ^m participants who missed an annual review, but returned the following year (counted in for the survival analysis). ^r participants returning after missing an annual review Reasons for leaving the trial: ^a lack of time=4, physician diagnosis=1, illness=3 (1 of these died of colon cancer a year later) ^b lack of time=5, changed mind=2, physician diagnosis=1, not known=2, died=1 ^c not known=2, mother died=1 ^d not known=1, family bereavement=1 ^enot known=1 ^flack of time=1, not known=1, illness=1, back surgery=1 ^g lack of time=1, illness=1^h lack of time=1ⁱ lack of time=1^j 1= completed to year 5 and died later of lung cancer

Figure 3

Progression to type 2 diabetes by trial group.

Figure 4

Relationship between changes in secondary outcomes and progression to T2D in trial participants (trial groups pooled). This figure shows the results of survival analysis based on beneficial change in secondary outcome measures maintained for two or more years. Intervention and control group data was pooled for this analysis.

Figure 5

Mean annual changes in secondary outcome measures by sustained beneficial change (A) and no sustained beneficial change (B) groups. This figure shows the range and distribution of change in secondary outcome measures in the two groups defined by A: 'beneficial direction of change in an outcome measure sustained for two or more years' and B: no beneficial direction of change in the outcome measure. Intervention and control group data was pooled for this analysis.