Heat Outcome Trial (HOT) Text – Pilot Randomised Controlled Trial of a tailored text messaging intervention for heat adaptation in older Australians

Brief Title: HOT Text Currently, generic heat warnings are the standard of care in public health notifications. However, such communication may lack efficiency, fail to reach the target population, or may lead to suboptimal behaviour change if it isn't timely, accessible, consistent or considered trustworthy. Understanding the barriers to receiving heat warning information will assist in mitigating health impacts from extreme heat exposure. We therefore propose to evaluate whether a tailored text messaging intervention can reduce patient reported heat symptoms, increase adoption of heat adaptive behaviours and reduce utilisation of health services during and after extreme heat days for older Australians (65 years and older). Materials provided: No physical materials provided. Procedures: This will be conducted as a pilot study. Trial participants will be randomly assigned to one of two arms: Control arm - this group will receive a heatwave warning forecast and general information on managing heat; Intervention arm - this group will receive a heatwave warning forecast and a tailored, disease- and location-specific advice messages via text (Short Message Service -SMS). Message length is estimated to be approximately 150 words or less, and will be one-way interactions i.e., participants will not be required to or able to provide a response. The intervention will be triggered by a rule-based algorithm using both Bureau of Meteorology (BOM) heat alert data, and participant (demographic, vulnerabilities, health status) data. Messages will be selected and tailored according to a message library developed by the research team (and informed by expert clinicians). Messages will be text-based and contain a link for accessing additional information e.g., health management actions. An example of tailoring may be: "Hi [Name], Pilot Heat Trial: Extreme heat in [LOCATION=district/post code] from [DATE] to [DATE]. You are at higher risk of heat distress. Stay cool, hydrated, and watch for signs of heat exhaustion. To find out more on this, Click Here. Below, we provide additional tips tailored to your condition [ACTION1: e.g. Speak to your GP about a COPD action plan] [ACTION 2: e.g. Monitor your symptoms for any signs of worsening respiratory conditions such as breathlessness, cough, and mucus production] [ACTION3: 3 e.g. Continue to monitor symptoms for several days after heatwave event]” where actionable content is specific to each participant. Post-intervention surveys for outcomes and intervention acceptability will be conducted, followed by focus groups to better understand the user experience (feasibility, barriers, and facilitators). Who: The research team, comprising investigators with expertise spanning information technology, climate and health, clinical care, consumer engagement, and research design, will deliver the intervention. Clinicians will inform the tailored text message content. Mode of delivery: MS Teams teleconferencing platform will be used for the Focus Group interviews. Survey data will be collected via the REDCap platform. Our experienced software development team will employ commercial off-the-shelf (COTS) technology platforms which will integrate participant data and weather data (from the Bureau of Meteorology) including heatwave warning data, to tailor messages. The virtual intervention will issue text messages facilitated though Amazon Web Services. Frequency of intervention: text message intervention will be delivered two days prior to forecast heat event, followed by a text message one day prior to the event. Intervention location: This pilot study will be conducted online at participants’ preferred location (e.g., place of residence) within the following three states: NSW, SA and VIC. How well: Intervention fidelity will be assessed through message compliance and engagement metrics e.g., percentage of messages opened, via survey.