DIAMOND extended follow-up
Research type
Research Study
Full title
Extended follow-up of participants in the DIAMOND randomised controlled trial.
IRAS ID
289925
Contact name
Elizabeth Morris
Contact email
Sponsor organisation
University of Oxford
Duration of Study in the UK
0 years, 11 months, 31 days
Research summary
Summary of Research
The DIAMOND trial (Ethics Ref: 18/SC/0071) was an individually randomised feasibility trial in which patients who had type 2 diabetes and a BMI ≥30kg/m2 were randomised to receive either a 12 week nurse-led low-energy, low-carbohydrate behavioural weight management intervention (the DIAMOND programme) or usual diabetes care. The DIAMOND programme consisted of an 800-1000kcal/day food-based, low-carbohydrate (<26% energy) diet for 8 weeks, followed by a 4 week weight maintenance period, and was supported by four 15-20minute appointments with a practice nurse. Usual care consisted of one appointment with the practice nurse to discuss “healthy eating” for diabetes. 33 patients from 3 UK general practices were recruited between April-October 2018. In the intervention group, 100% of participants allocated to that group attempted the intervention. The behavioural programme was delivered with high fidelity in 100% of consultations and follow-up at 12 weeks was complete (bar one person in the control group who died), so the trial passed all pre-specified feasibility criteria. At 12 weeks, those allocated to the DIAMOND programme lost on average 9.5kg (SD 5.4), while those assigned to usual care lost an average of 2kg (SD 2.5kg) – an adjusted mean difference of -7.5kg (95% confidence interval -11 to -4kg, p<0.001) favouring the intervention. Mean (SD) reduction in HbA1c in the intervention group was 16.3mmol/mol (13.3mmol/mol), compared with 0.7mmol/mol (4.5mmol/mol) in the control group – an adjusted difference of -15.7mmol/mol (95% CI -24.1 to -7.3, p<0.001) favouring the intervention group.After study completion, study sites (GP PIs and research nurses), co-investigators, and healthcare professionals at dissemination events have expressed an interest in the longer-term outcomes from this initial cohort. Additionally, patient participants in the qualitative focus groups expressed interest in whether the researchers could follow up with them to learn from what happened to them after the study had finished. Understanding changes in clinical outcome measures and participant behaviours could inform the design, specifically the maintenance programme, of the full-scale RCT testing this intervention which is in development.
The aim of this study is to contact the original participants in the DIAMOND trial, to gain permission to gather data from their primary care records about their HbA1c and body weight following completion of the study, as well as collecting other information on their health, weight and diabetes control efforts.Summary of Results
This study set out to follow up participants who took part in the original DIAMOND study, which compared usual NHS diabetes care with whether it was feasible to provide 12 weeks of support from practice nurses for people with type 2 diabetes to attempt a low-carbohydrate, low-energy diet (the “DIAMOND” programme). In this follow up study we collected data on people’s weight, blood tests including average blood glucose levels (HbA1c), and blood pressure, as well as their current dietary habits, up to an average of 29 months after their first assessment as part of the study. We also spoke to them to understand their experiences of managing their weight, diet and diabetes themselves after the original study finished.We were able to contact and collect follow up data for 19 of the original 31 participants who had given us their consent to follow them up in the future; 14 who had been allocated to try the "DIAMOND" diet and support programme, and 5 who had continued to receive usual care.
Our main outcomes were to look at the effect of having taken part in the original DIAMOND study on the participant’s weight and HbA1c results, and we found no significant difference in either of these measures after 1 or 2 years, between the two groups. However, 5 of the participants (36%) who had received the “DIAMOND” programme had been coded as having a diagnosis of diabetes in remission (normal blood glucose levels without needing medications) during the follow up period, with 3 (21%) still meeting the criteria for remission at last HbA1c measurement, compared to 0 (0%) of people who had continued to receive only their usual care).
The available data was limited by the COVID-19 pandemic in the intervening months, as this had prevented the usual diabetes follow up appointments and blood tests being carried out for many people. Participants also described the circumstances of the pandemic as having negatively impacted their diabetes control, and diet and weight management efforts.
Full results of the other outcomes of the study (blood pressure, markers of cardiovascular risk, and dietary patterns) and full results of the interview study will be available in due course.
REC name
North West - Preston Research Ethics Committee
REC reference
21/NW/0018
Date of REC Opinion
24 Feb 2021
REC opinion
Further Information Favourable Opinion