"I got hit by a car. Within 48 hours, I had all the symptoms of a type 1 diabetic," Ms Ferguson, 58, said.

"Whether the shock brought it out, I don't know."

Doctors didn't initially consider type 1 diabetes because it's an unusual disease to get at Ms Ferguson's age.

"Because it's an autoimmune disorder, it can sit there dormant in your body."

Doctors told her the accident may have been a coincidence. "But I think there has to be a cause," she said.

She was initially diagnosed with type 2 diabetes.

"Unfortunately, that sent me into hospital numerous times from passing out, losing consciousness and being extremely ill," she said.

Monitoring blood glucose levels is crucial for managing type 1 diabetes. After initially using the finger-prick method to test herself, she discovered continuous glucose monitoring (CGM) devices about 18 months ago.

The wearable devices measure and display glucose levels around the clock. They include a sensor, which is a small electrode inserted under the skin, usually on the arm or abdomen.

They can be programmed to sound alarms and send warnings if glucose levels are outside the target range.

"It's given me much greater control of my diabetes," she said, adding it provided immediate information on her smartphone.

"It gives me the ability to track how I'm going and look at what's causing it."

The device reduces the risk of her passing out, which is a major concern - particularly as she is a full-time carer of her disabled granddaughter.

Across the country, about 127,000 people have type 1 diabetes.

Ms Ferguson, of Cessnock, in NSW's Hunter region, doesn't receive a federal subsidy for the CGM device, which can cost $2500 to $5000 a year.

People under 21, pregnant women and those with concession cards get the devices for free, but those who work must pay for it.

"It's become a really expensive exercise just to stay alive," Ms Ferguson said.

She has other autoimmune disorders - cold urticaria, coeliac disease and gastroparesis - that are also costly to manage.

She urged the federal government to consider a subsidy for CGM devices for all those who need it.

The federal health department said the government "provides fully subsidised CGM products to those people most in need, clinically and financially".

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A department spokesperson said more than 58,000 people were eligible for this.

"The government provides considerable financial support to people with diabetes through subsidies of essential medicines, like insulin, under the Pharmaceutical Benefits Scheme (PBS) and diabetes-related products through the National Diabetes Services Scheme (NDSS).

"In 2020-21, PBS expenditure on medicines for diabetes was over $709 million. Expenditure on products for diabetes supplied through the NDSS was over $186 million."

The spokesperson added that the government was considering a proposal from JDRF [Juvenile Diabetes Research Foundation] Australia and would "respond in due course".

The JDRF is seeking "equal access to life-saving diabetes technology [including CGMs] for all", based on need not age.

Dr Stephen Thornley, an endocrinologist, said improved control of type 1 diabetes with CGM devices reduced hospitalisation and health-system pressure.

Dr Thornley said even a contribution towards the cost would help affected patients.

"Some patients would be happy to partially pay."