That's interesting, though without access to the actual study that is summarised it's impossible to judge the quality of the results. (Normally if you read the full study you get references to the source studies.)
Also, in the interests of clarity for those using hba1c in mmol/mol and bgs in mmol/L , ie converting from DCCT to IFCC units, an improvement of hba1c of 0.25% is about 3 mmol/mol and 18mg/dL is 1 mmol/L
Maybe
@Oldvatr has a comment????
(EDited to add, I see you did while I was posting
)