A team from the University of Manchester has been looking at diagnosis rates between 2000 and 2015.
Using data from just over 146,000 people, they found that 1.6 per cent of those individuals were diagnosed with type 2 diabetes after a month, followed by 4.2 per cent after six months and 20.4 per cent converted after four years.
The researchers are not able to confirm why rates have dropped so significantly, but suspect there are several changes which may have contributed to the reduced rates.
Lead researcher Dr Rathi Ravindrarajah, from the University of Manchester, said: “We are not certain why this is, but we suspect it’s a combination of good preventative work by the NHS and changing definitions of non-diabetic hyperglycaemia.
“This sample is large enough to give a good representation of what is going on across the UK.
“The reduction in conversion rates reflects changes in the definition of pre-diabetes and to some extent NDH, at least in the UK, with people diagnosed with NDH more recently having lower conversion risks. This has implications for interventions, like the NHS Diabetes Prevention Programme.”
She added: “Non-diabetic hyperglycaemia refers to levels of blood glucose that are increased from the normal range but not yet high enough to be in the diabetic range.
“We hope this study will encourage policy makers to be consistent in their definition and recording of pre-diabetes, which has changed a few times in the last decade.
“Diabetic preventing programmes might need to target the individuals who are at higher risk of conversion to type 2 diabetes, as identified in this study.
“Policy makers who aim to prevent conversion may wish to prioritise certain recipients who are at higher conversion risk, especially when resources might be limited.”
The findings of the study have been published in the BMJ Open.