Residents of Melbourne’s wealthy eastern and bayside suburbs are among the highest users of colonoscopies in Australia while their poorer neighbours in Frankston top the state for using mental health plans for psychological care.  

A new atlas of health care has also revealed that children under the age of 17 in Sale have the highest rate of antidepressant drug use in Victoria, while people over 65 in Melbourne’s wealthy inner south-eastern suburbs are Australia’s greatest users of anti-psychotic medicines.

In a worrying discovery, there are huge variations in surgery across Australia, too, with women in Victoria’s Latrobe Valley having the highest rate of hysterectomies (removal of the uterus) – five times higher than other areas. And children under 17 in Glenelg are the most likely in Australia to have their tonsils removed. The shire, in Victoria’s south-west, has six times the rate of tonsillectomies compared to other parts of the country.   

Australia’s first-ever report on the way health care varies nationally was on Thursday released by the Australian Commission on Safety and Quality in Health Care.

The Australian Atlas of Healthcare Variation found stark differences in the rates of medical and surgical interventions, which were largely “likely to be unwarranted”. 

Professor Villis Marshall, Chair of the Commission’s board said “Australia has a world-class health system but it is crucial we study what these variations might tell us about how to do things better and more consistently in the future.”

For some procedures there were big differences between states and between regional and metropolitan areas. Women in regional areas were more than five times more likely to undergo a hysterectomy tthan in metropolitan cities, ranging from 225 per 100,000 in the Northern Territory to 349 per 100,000 women in Western Australia.

Hysterectomies were often performed to treat heavy menstrual bleeding, and less commonly to treat chronic pelvic pain and endometrial cancer.

The report said doctors and patients in different areas could have used different criteria to decide when to recommend and agree to treatment, and specialists may be more available in metropolitan areas.

“Even when the highest and lowest rates were excluded, the rate was almost three times higher in one local area compared to another,” the report found, after the authors examined data from the Medicare Benefits Schedule, the Pharmaceutical Benefits Scheme PBS and national patient admissions data.

While lower back or lumbar spine surgery was usually considered the “last resort” to treat back problems, more than 17000 were performed nationally between 2010 and 2013. Admission rates for the surgery were higher in inner regional areas than in major cities, and lowest in remote areas. The ACT had the lowest average number of admissions of 60 per 100,000 adults, and Tasmania had the highest at 113.

There were also marked variations in how frequently children younger than 17 were prescribed medication for ADHD, depression and psychotic disorders.  NSW and Queensland were had the highest rates of dispensing the medicines. 

The report  suggested a number of reasons for the differences, including clinical guidelines not been followed and differences of opinion among patients and doctors about treatment. 

The report said it was difficult determine what level of treatment or intervention for various conditions was unnecessary across Australia. “The challenge in identifying and addressing unwarranted variation is that for many healthcare interventions we do not know what rates of intervention deliver the best outcomes for patients and the broader community,” the report said.

Health literacy rates also needed to be improved – it estimated about 60 per cent of Australians had low health literacy – to help patients understand the decisions they make about their health. This was particularly needed in disadvantaged areas where limited understanding, coupled with poor access to health care services made it harder to compare the risks with the benefits of surgery and understand different treatment options.

The report called on state and territory health departments to review the stark differences in treatment rates and come up with plans to address them.