Dr Rowan Hillson said diabetes care had become patchy under PCT control. Without concerted effort this could increase as potentially more numerous GP consortia take control, she said.
Addressing members of the all party parliamentary group for diabetes last week, Dr Hillson said: 'I have concerns about potential fragmentation.
'We have to make sure it doesn't happen. I strongly believe that people with diabetes and professionals must have ready access to specialist diabetes expertise.'
The whole care pathway must be considered when delivering the most cost efficient and effective diabetes care, from diagnosis and personal management to hospitalisation, Dr Hillson said.
Although consortia should be mindful of the risk of fragmentation, in principle GPs are well placed to ensure diabetes care adheres to this model, she added.
In the last National Diabetes Audit for 2008/9, just 32 per cent of type-1 diabetes patients and 51 per cent of type-2 diabetes patients received all care processes recommended in the diabetes national service framework, such as blood glucose and cholesterol checks.