Rationale and impact of the new recommendations
This section explains why the committee made the 2017 recommendations on intensive lifestyle-change programmes and metformin.
A health economic model showed that lifestyle-change programmes are cost effective for all people at high risk of diabetes, providing support to the existing recommendation to offer the intervention to this group of people. The model also showed that lifestyle-change programmes are particularly cost effective for people with higher HbA1c or fasting plasma glucose levels. Therefore, the committee determined that, in instances where offering the intervention to all high-risk people is not possible due to capacity constraints, lifestyle-change programmes should be prioritised for people with a fasting plasma glucose of 6.5 to 6.9 mmol/l or HbA1c of 44 to 47 mmol/mol. The committee also agreed that people should be given information about their diabetes risk because this was recommended in the previous version of NICE guidance on type 2 diabetes prevention based on the expert view of the previous committee.
The committee also recognised that people with mental illness or dementia often have poorer physical health and would therefore benefit from testing and, if needed, intervention to reduce their risk of type 2 diabetes. Therefore an additional recommendation was made to ensure that intensive lifestyle-change programmes are designed to help as many people as possible to access and take part in them.
The results of the economic modelling also showed that, in the high-risk population overall and in most subgroups, lifestyle-change programmes are more clinically and cost effective than metformin. They also showed that, compared with control alone, metformin is cost effective in the high-risk population overall, and for most subgroups. Therefore, the committee agreed that metformin could be used in support of lifestyle change when blood test results have deteriorated despite someone taking part in these programmes or if they can't take part for some reason. They also agreed that metformin could be used for people whose BMI is over 35 when their blood test results have deteriorated because the model showed that metformin is particularly clinically and cost effective for this group.
The 2012 version of this guideline recommended that intensive lifestyle-change programmes should be offered to people at high risk of type 2 diabetes. The committee also recognised that intensive lifestyle-change programmes should be designed to help as many people as possible to access and take part in them. However, providing these programmes to all these people has a large resource impact. To make the most of resources commissioners may need to prioritise subsets of the population.
The NHS Diabetes Prevention Programme is currently being implemented throughout England in response to the 2012 recommendations in this guideline. Implementing the 2017 recommendations will allow this programme to be initially targeted at groups of the population who will benefit most, in a way that is consistent across the UK.
The updated recommendation on metformin reflects current practice, so the committee noted that it shouldn't have an impact.