The question was about whether it's possible to be on the QOF Non-Diabetic Hyperglycaemia (NDH) register at the same time as the diabetes register, and if having a diagnosis of diabetes automatically removes the patient from the NDH register, or if any manual action is needed.
Answer is:
The second rule of the NDH register excludes patients with diabetes BEFORE this contract year.
So the answer is, if you have diabetes prior to this contract year you won't be in the NDH register. But it is possible to be on both the NDH AND QOF register for the remainder of the contract year - and the at the start of the following contract year the patient will be removed from the NDH register (as next year their diabetes diagnosis will be before the contract year for date of diagnosis).
The rationale for this is probably to recognise work done when the patient had pre-diabetes (NDH) before they were formally diagnosed with diabetes - an HbA1c test is required by NDH001, and is the measure for diagnosing diabetes. Why should a Practice be penalised for diagnosing somebody with diabetes?
NDH001
Something else to bear in mind is that whilst a patient can appear on both registers and has had an HbA1c result which puts them in the Population Included list of DM020/DM021, some patients may not appear in NDH001. The reason for this that rule 2 feature 2 of NDH001 requires the HbA1c to have been recorded BEFORE the diabetes diagnosis - note less then 0 days after so it might be a little unfair if the result came in and the diagnosis was coded on the same day as it doesn't count.

The NWL ES takes a different approach - once diagnosed with diabetes, patients are immediately removed from the NDH register.