Objectives There are many barriers to clinicians understanding and effectively communicating risks and benefits of health care to patients. One major barrier is the ability to confidently recall the evidence and guidelines at the time of decision making.

The Emergency Department (ED) can be a particularly challenging setting to recall and effectively communicate the complex risk-to-benefit ratio of common tests and treatments. Limited time, significant workloads, fatigue and managing distressed patients can inhibit recall and discussion of risks and benefits. Not discussing risks and benefits effectively can contribute to overdiagnosis and overtreatment.

75% of patients presenting with back pain to ED will receive low-value care such as non-indicated diagnostic imaging, opioids, or both. Using strategies adapted from behavioural economics could promote better care. Cues and reminders at the time of decision making may make it easier for clinicians to access and discuss the risks associated with non-indicated imaging and opioids with their patient. No trial has examined this approach to reducing overdiagnosis.

Our objective is to investigate the effectiveness of using behavioural strategies to support clinicians to communicate the risks and benefits of commonly overused tests and treatments for back pain.

Methods NUDG-ED is a 2x2 factorial, open label, before-after, cluster randomised controlled trial. ED clinicians who manage back pain, and 2416 adult patients presenting to ED with uncomplicated back pain will be recruited from 8 hospitals in Sydney, Australia.

Two behavioural strategies will be tested in the trial: one directed at patients and the other directed at clinicians. The patient intervention provides information on the risks and the lack of benefits of imaging and opioids for low back pain, in the ED waiting room. The information will be presented on digital posters in the waiting room with access to more information via a QR code. The clinician intervention uses a computer alert to provide relevant information on the risks for imaging and opioids for uncomplicated back pain at the time of decision making. They are provided an information brochure that they can provide to patients, encouraging a discussion on the use of diagnostic imaging and opioids and providing evidence-based alternatives. These strategies combine theory and evidence from behavioural economics that suggest decisions are informed by the context and information available in moment of decision making.

The primary outcome will be the proportion of encounters for uncomplicated back pain where a person received low-value care, assessed by chart review. Secondary outcomes include clinician knowledge; patient reported outcomes; and cost-effectiveness of the interventions.

Results We will provide an update on the NUDG-ED trial, which launches in 2024. We will present the behavioural theories and consumer feedback that have informed our intervention design.

Conclusion NUDG-ED tests scalable interventions that could increase access to relevant information, at the time of decision making, encouraging a discussion of risks and benefits. This trial has the potential to improve care for patients presenting to the ED with low urgency conditions where overdiagnosis and overtreatment is common.