More than a quarter of NHS hospital beds could be taken up by diabetic patients by 2030, according to forecasts.
A report by Diabetes UK last year estimated that one in four inpatients would have type 1 or type 2 diabetes as well as their main illness.
But there are concerns the figure is too conservative as the number of people developing the condition because they're obese continues to rise.
Currently, one in every six inpatients (18 per cent) has diabetes and, although the vast majority of them (92 per cent) aren't admitted because of it, the condition can complicate their recovery and make them more likely to die while in hospital.
There are about 4.7million people in the UK with type 1 or type 2 diabetes – about a million of them don't know about it – and this is on track to hit 5.5m in 11 years.
The warning comes as researchers yesterday revealed diabetes diagnoses are rising in the under-40s because of high-fat diets and lazy lifestyles.
More than one in four hospital patients could be diabetic in 11 years' time. One expert said current predictions about the toll type 2 diabetes is taking on the nation's health will get worse before they are fulfilled because so many people are obese (stock image)
One senior heart surgeon in Birmingham said wards in his hospital are 'full' of diabetic patients with sometimes life-threatening complications.
The illness can cause serious nerve damage, gangrene, heart problems and stroke because it causes blood sugar levels to spike which damages the veins, arteries and internal organs.
Although the vast majority of patients – 92 per cent – aren't admitted to hospital because of their diabetes, it can complicate their recovery.
'At Birmingham Heartlands Hospital our wards are full of patients suffering complications of diabetes.,' Martin Claridge told the Daily Express.
'This can include [kidney] failure requiring dialysis and patients with severe infections, including those requiring emergency amputations of their lower limbs to save their lives.
'Lots of patients admitted for other reasons have diabetes.
Type 2 diabetes is a condition which causes a person's blood sugar to get too high.
More than 4million people in the UK are thought to have some form of diabetes.
Type 2 diabetes is associated with being overweight and you may be more likely to get it if it's in the family.
The condition means the body does not react properly to insulin – the hormone which controls absorption of sugar into the blood – and cannot properly regulate sugar glucose levels in the blood.
Excess fat in the liver increases the risk of developing type 2 diabetes as the buildup makes it harder to control glucose levels, and also makes the body more resistant to insulin.
Weight loss is the key to reducing liver fat and getting symptoms under control.
Symptoms include tiredness, feeling thirsty, and frequent urination.
It can lead to more serious problems with nerves, vision and the heart.
Treatment usually involves changing your diet and lifestyle, but more serious cases may require medication.
Source: NHS Choices; Diabetes.co.uk