People living with chronic respiratory disease and those who smoke also face a higher risk, along with immuno-compromised people such as cancer patients.

Ros Brown knows she is in the high-risk category for COVID-19.

Ms Brown, from the NSW Hunter region, had a massive heart attack seven years ago.

"Any sort of co-morbidity, whether it be heart or lung disease or other conditions puts you in a higher risk category," the former John Hunter Hospital nurse said.

"I'm self-isolating as much as possible."

She treats everybody as though they have COVID-19.

"I keep my distance. You just don't know who's got it."

A Chinese study that involved 53,000 patients with confirmed cases of COVID-19 found those with underlying medical conditions including high blood pressure, diabetes and cardiovascular disease were two to three times more likely to progress to severe illness.

In another study, the Chinese Centre for Disease Control and Prevention found the death rate for COVID-19 patients with cardiovascular disease was 10.5 percent.

The centre examined 72,314 records of people diagnosed with COVID-19.

Patients with no pre-existing medical conditions had a fatality rate of 0.9 per cent.

Death rates for people with diabetes was 7.3 per cent, chronic respiratory disease 6.3 per cent, high blood pressure 6 per cent and cancer 5.6 per cent.

As has been widely reported, older people face the highest risk from COVID-19. The federal Department of Health said people aged 70 and over and those aged 65 and over with chronic medical conditions were at greater risk of more serious illness, if they were infected with coronavirus.

The Hunter Region has tens of thousands of people aged over 65. It should be noted that Australia has recorded a death rate of 1 per cent from more than 6300 COVID-19 cases.

China had a death rate of 4 per cent, but its figures aren't thought to be reliable because of its totalitarian propaganda system.

Italy has a death rate of about 13 per cent, the UK 13 per cent and Spain 10 per cent.

Italy's National Institute of Health said 99 per cent of COVID-19 patients who died in Italy had at least one pre-existing condition. Almost 50 per cent of the patients who died had three pre-existing conditions.

A quarter of those who died had two pre-existing conditions and a quarter had one pre-existing condition.

The researchers examined 18 per cent of about 3000 coronavirus deaths in Italy. The most common conditions among those who died were high blood pressure (76 per cent), diabetes (35 per cent) and heart disease (33 per cent).

The Italian research has highlighted the high smoking rate among Italians as a factor in the country's high death rate from COVID-19.

The Chinese research found that smokers were one to two-and-a-half times more likely to experience a severe illness from COVID-19.

University of Newcastle Professor Billie Bonevski said quitting smoking was "a good idea at this time".

"People with chronic diseases are at higher risk for more severe COVID-19 symptoms and smoking is a major cause of those listed," Professor Bonevski said.

"An important issue for people who smoke is that the hand-to-mouth action of smoking may increase the risk of contracting COVID-19, as the recommendation is to avoid touching your face."

The Chinese research also found that people with chronic obstructive pulmonary disorder [COPD] were more likely to become severely ill. Kidney disease was also thought to pose a higher risk.

When it comes to heart attacks and other emergencies, Hunter residents have been urged to remember to contact triple-0 if they find themselves in trouble.

"Some people might think that the hospitals are so busy already that they shouldn't be a bother," one Hunter health-sector worker said.

"But hospitals and paramedics are equipped to deal with life-threatening emergencies [in addition to COVID-19 cases]."

As for Ms Brown, she feels good despite the heart problems she has faced.

But she knows the risk remains.

"I'll always be a cardiac patient for the rest of my life. I've got to be really careful."