The NHS in St Helens spends £29 more on diabetes drugs per patient than it did five years ago, figures reveal.
The charity Diabetes UK says the disease is "one of our biggest health crises", and the health service allocated more than £1 billion in the last financial year alone to devices and drugs to deal with it.
NHS Digital figures show that St Helens CCG forked out £4 million on prescribing medicines for diabetes in 2018-19 – an average of £309 on each patient, up from £280 in 2013-14.
Across England, the average spend was £328 last year.
With spend varying between different parts of the country, Diabetes UK policy manager Nikki Joule said: "There are, of course, multiple factors to consider, but it is of greater concern that the areas that spend less may not be ensuring everyone is on the most effective medications for them.
"However, it is vital that drugs being prescribed are reviewed regularly, not only to ensure patients receive the most effective therapy, but also to reduce waste."
The NHS bill for treating diabetes has ballooned nationally over the last five years, from more than £800 million in 2013-14 to nearly £1.1 billion in 2018-19.
Ms Joule said the major factor in the increased expenditure was more people having the disease.
She added: "The number of people with diabetes has doubled in the last 20 years, so it's no surprise that the cost of prescriptions to the NHS has dramatically increased as well.
"But with the bulk of the overall cost of diabetes spent on managing devastating, and costly, complications – such as cardiovascular and kidney disease – the answer is not to reduce spend on medications to treat the condition, but to ensure access to the medications, technologies and health services people need to live well with their diabetes."
Diabetes is a chronic disease in which the body either cannot produce insulin or cannot properly use it.
If not controlled, it can lead to heart attacks and strokes, as well as problems with the kidneys, eyes, feet and nerves.
Diabetes drugs accounted for 10% of all money spent on prescriptions in St Helens last year, according to the figures.
Overall, St Helens CCG issued 203,000 prescriptions for Type 1 and Type 2 diabetes, for around 12,800 patients with diabetes.
The data also shows that the NHS spent £1.5 million on insulin in St Helens. Devices to monitor patients' health, like glucose monitors or fitness trackers, cost £734,000.
An NHS spokesman said: "Thanks to better diagnosis, the NHS is caring for more people with diabetes than ever before and this is another reminder of the urgent need to prevent Type 2 diabetes from developing in the first place.
"Diabetes and its complications cost the NHS billions every year, which is exactly why our NHS Long Term Plan will help 200,000 people a year to benefit from our world-leading Type 2 diabetes prevention programme."