Three thousand GPs who received ‘nudge’ letters over their high referral rates for musculoskeletal imaging were unwitting guinea pigs in research involving the federal Department of Health.

Back in 2019, the department announced it was sending letters to GPs to “draw attention to overdiagnosis and over-treatment”.

According to a new study published in JAMA on Tuesday, the doctors were in the top 20% of referrers for at least four of 11 “overused” imaging tests, including those for the cervical spine, shoulder, hip and knee.

As a result, they were sent a three-page audit letter signed by then Chief Medical Officer Professor Brendan Murphy, urged them to reflect on their practice.