The Australian Institute of Health and Welfare says there were 11.6 million public and private hospital admissions in 2021-22, a 2.1 per cent decrease from the previous year.
It said this followed a 6.3 per cent increase from 2019-20 to 2020-21 and a 2.8 per cent decrease from 2018-19 to 2019-20.
The 'MyHospitals' update reveals that hospital admissions have fluctuated throughout the pandemic.
"Prior to the pandemic, hospitalisations increased by an average of 3.3 per cent per year between 2014-15 and 2018-19. However, the peak of the pandemic has thrown the steady growth trend off balance," said AIHW spokesperson Dr Adrian Webster.
There were 7.3 million (63 per cent) same-day hospitalisations and 4.3 million (37 per cent) overnight hospitalisations in 2021-22. This equates to a 2 per cent and 2.2 per cent decrease, respectively, from the previous year.
The average length of stay for overnight hospitalisations in public hospitals increased by 7.1 per cent (5.48 to 5.87 days), while private hospitals increased by 1.4 per cent (5.11 to 5.19 days).
"The changes to average length of stay likely relates to restrictions on certain activities. For example, emergency admissions tend to have longer lengths of stay than admissions for elective procedures so restrictions on elective surgery numbers may have inadvertently increased the average length of stay.
"In general public and private hospitals tend to provide different types of care," said Dr Webster.
Most hospitalisations for certain infectious and parasitic diseases (gastroenteritis and colitis) and conditions in the perinatal period (short gestation and low birthweight) were provided in public hospitals.
The majority of hospitalisations for treating diseases of the eye (cataracts) and musculoskeletal system (arthritis of the knee) were provided in private hospitals.
People aged 65 and over make up 17 per cent of the Australian population but account for 4 per cent of hospitalisations and 49 per cent of patient days.
The report also contains information on the number of hospitalisations involving a COVID-19 diagnosis, showing a significant increase from 4,700 in 2020-21 to 263,400 in 2021-22.
"While there has been a substantial increase in the number of hospitalisations involving a COVID-19 diagnosis, this does not necessarily reflect the severity of the illness; it could be related to the widespread nature of COVID-19. In many cases patients are admitted with COVID-19, not necessarily because of COVID-19," said Dr Webster.