Heart failure mortality rates in Australian and New Zealand hospitals vary widely, with some having double or triple the death rate of others, study results show.

In what researchers believe is the first large study of 30-day heart failure mortality and readmission rates outside the US, results for 392 hospitals and more than 154,000 patients admitted for the condition have been analysed.

The data covering the period 2010-15 included all Australian public hospitals and most private hospitals in all states and territories except the NT.

The median death rate within a month of admission was 10.7% and unplanned readmission within 30 days of discharge occurred in a median 22.3% of patients, reported the researchers, led by Brisbane cardiologist Associate Professor Isuru Ranasinghe, of the Prince Charles Hospital and the University of Queensland.