Remission target - 5.7% or 6.5% Hba1C

I have been taking an interest in the concept of remission recently... I am about to get my 2nd NHS Hba1C reading much earlier than I'd expected, and I know from recent home testing with an AC1now test kit and Libre that - barring significant measurement error on both - it will be below the UK target remission threshold of 6.5% (albeit this is being artificially helped by 500 mg/day metformin).

However when digging into remission values, I found the following contradicting information from 2009:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2768219/

To quote;
Partial remission is sub-diabetic hyperglycemia (A1C not diagnostic of diabetes [<6.5%], fasting glucose 100–125 mg/dl [5.6–6.9 mmol/l]) of at least 1 year's duration in the absence of active pharmacologic therapy or ongoing procedures.

Complete remission is a return to “normal” measures of glucose metabolism (A1C in the normal range, fasting glucose <100 mg/dl [5.6 mmol/l]) of at least 1 year's duration in the absence of active pharmacologic therapy or ongoing procedures.

The threshold for "pre-diabetes" is taken as >5.7%, so remission is taken in the UK as being a return to a pre-diabetic threshold not that of the healthy populace. The question then is, are either of these enough to address health risks and so meaningful as a target. Turns out this has already been looked into by another member, pavlosn:

https://www.diabetes.co.uk/forum/threads/can-hba1c-be-too-low.68973/

The third set of diagrams he pasted shows a morbidity increase for Hba1C which starts to ramp up at around 6%. What I can't find is any clinical data that supports a 6.5 % target as being a meaningful value.

Given above the 5.7% target makes sense to me.

I've today found a study which came up on a new search in google for slightly different terms, dated 2020 (published 2021), which actually answers a lot of my questions and confusion, and confirms EllieM's input (thanks for that). Its a meta-study on whether the 6.5% diagnostic threshold for diabetes is appropriate, but I also think it helps to give clarity on remission thresholds as well. The link is at:

https://link.springer.com/article/10.1007/s00592-020-01606-5

I won't repeat the whole huge thing, but the conclusion was:

In conclusion, based on the strongest data of moderate retinopathy, this systematic review and meta-analysis is in accord that the HbA1c diagnostic cutpoint of 6.5% (48 mmol/mol) is highly specific for diagnosing T2DM, though the increased prevalence of retinopathy in those aged 55 years or greater and in African-Americans may suggest a lower threshold is appropriate for those groups. However, this analysis highlights that diabetic microvascular complications commonly occur at lower HbA1c values, and the sensitivity of diagnosing T2DM may improve with a lower diagnostic cutpoint. There is a need for studies that standardize the definition of minimal diabetic retinopathy with more sensitive measures of nephropathy and neuropathy to determine if a lower threshold is appropriate.

So 6.5% is a meaningful retinopathy threshold for some racial groups (but possibly not all); and some other forms of damage are still at higher risk of occurring over time below this threshold, to an unknown and as yet un-investigated degree.

Yup I'm sticking to 5.7% myself.

KennyA said:

I had a look in Bilous' Handbook of Diabetes, which is what the NHS regards as the key textbook for diabetes. It does not mention remission at all, but then again it deals with diet and diabetes in about half a page.

Click to expand...

I try to avoid being overly cynical about the NHS, but that did make me grimly amused. How awful yet appropriate.