A new study has revealed many Australian diabetics don't know about kidney and heart failure - two common, deadly complications caused by the disease.

If Joseph Kizana had known he would suffer organ failure, spend 300 consecutive days in hospital and lose three toes when he was diagnosed with diabetes at 27, he would have lived his life differently.

Now 56 with a laundry list of health conditions that threaten all aspects of his life, Mr Kizana wishes he had known how serious the condition could become.

"I wish I'd had a crystal ball that could show me myself at my worst, when I was laying in hospital for 300 days from mega complications to different organs," he told AAP.

"If I could go back 20 years and start again, I'm sure I'd be totally different person."

He was an "idiot" after his diagnosis, he says, but didn't know better.

"The idea of carrying an insulin pen with me and jabbing myself every time I had dinner or lunch just didn't go down," he said.

"No matter how many people told me that diabetes is a horrible disease, I couldn't feel it and so I was just too careless."

But Mr Kizana isn't alone.

A recent survey of 1000 type-2 diabetics by Diabetes Australia and Kidney Health Australia found many don't know about the serious complications the disease can cause.

Roughly one in two will develop chronic kidney disease, yet 40 per cent did not know or were unsure of what the condition was.

Despite being twice as likely to develop heart failure and almost 30 per cent more likely to die of it, 20 per cent of respondents also did not know what heart failure was.

These are statistics Mr Kizana now knows all too well, and he's urging other diabetics to learn from his mistakes.

His kidney function is the worst it can get, he has three heart conditions and relies on daily medication to keep him alive.

He can't drive, has poor vision, limited mobility and no sensation from his knees down.

"I'm really below average in terms of my health and my doctors certainly don't expect me to have the longevity that people of my age group would normally expect," Mr Kizana said.

He is only one step away from dialysis, which with a bad heart, isn't something that his doctors want for him.

"The options really aren't great," he said.

Things can be different though, if diabetics take their medication, work hard with their GPs and maintain a healthy diet right from their diagnosis, he warns.

"I think to myself, you're an idiot. It's a horrible condition to have, but so easily managed.

"If I'd seen that when I was diagnosed, maybe that would have changed things for me."