The goal of this clinical trial is to improve health equity within outpatient service access. This is through design and behavioural science-informed interventions that aim to improve rates of first outpatient appointment attendance. Health equity refers to the avoidable and unfair differences in health access, outcomes and experience between groups or populations. Outpatient services are those appointments where advice from a specialised medical professional is provided to a patient in a clinic setting.

This clinical trial aims to test different ways of supporting people to attend their first outpatient appointments at five clinical specialties (ophthalmology, gastroenterology, colorectal surgery, cardiology and plastic surgery) at Imperial College Healthcare NHS Trust (ICHT). It is specifically focused on improving attendance for people who are most likely to miss their appointment based on ICHT data, which includes people from minority ethnic backgrounds and people living in the most deprived postcodes.

The main question this clinical trial aims to answer is:

• Do behavioural science-informed message interventions improve rates of first outpatient appointment attendance in patients facing inequity of access based on ethnicity and deprivation?

The secondary questions this clinical trial aims to answer include:

• Do behavioural science-informed message interventions improve rates of first outpatient appointment attendance across all patient groups?
• Do behavioural science-informed message interventions increase the number of patients who "self-cancel" their appointment if they need to?
• In which patient groups did the message interventions have most impact, e.g., a certain age range?
• Which factors were associated with improved outpatient attendance rates specifically in participants from minority ethnic groups or living in area with highest level of deprivation?
• What was the overall outcome of all first outpatient appointments included in the clinical trial?
• What was the overall successful message delivery rate for the messages sent as part of the study? Were there particular participant groups that were more likely to have an undelivered message?
• What was the overall outcome of appointment attendance for people who received a text message intervention compared with receiving a text message and/or email intervention?
• How well did participants engage with the message interventions e.g. did they click the link provided in the message?

This clinical trial has been designed as a non-randomised controlled trial, aiming to test the impact of three design and behavioural science-informed interventions on first outpatient appointment attendance in groups at highest risk of inequity. The interventions will be tested in five clinical specialties at ICHT - cardiology, gastroenterology, ophthalmology, plastic surgery, and colorectal surgery. The study is estimated to last 48 weeks. The messages sent as part of the trial will be deployed by ICHT staff members who manage outpatient services.

Prior to conducting this trial, three message and web page interventions were co-designed with a diverse group of public members with good representation from the IMD and ethnicity groups facing inequity of access, ICHT staff, researchers, and behavioural science experts. These interventions were based on insights on barriers to appointment attendance gained from short qualitative interviews conducted with people who had missed appointments at ICHT and who also faced inequity based on ethnicity or deprivation.

This study has been designed to have four arms. These four arms will include a control arm, that will be the standard practice communication strategy used by each clinical specialty, as well as three intervention strategies. Currently the standard communications that patients receive before an outpatient appointment varies, but commonly patients receive a reminder 3 and 7 days before the appointment at ICHT. The three co-designed interventions for the trial are all based on an additional message reminder to this existing reminder schedule that will be sent to patients 14 days before their appointment. DrDoctor is the message provider that is currently used by ICHT and that the interventions will be housed in. The web pages will be housed in the existing ICHT website. All five clinical specialties will spend one week in each study arm, before cycling to the next arm. They will move from one arm to the next, until they return to their original study arm, resulting in continuous four-week cycles until the final study period is reached. Therefore, the five clinical specialties will all be in the same study arms at the same time and go through the cycle together until the sample size is reached. This method of allocation of clinics to study arms has been selected as it is not possible with the current technology being used at ICHT to randomise participants within clinics to different study arms.

Data will be collected on the message delivery and appointment outcomes throughout the trial and full analysis will take place at the end of the trial, once the sample size has been reached. The rate of missed appointments will be monitored throughout the study to assess if there is any backfire effect of the interventions.

For the first approximately 20 weeks of the study, only participants who received the intervention as a text message will be analysed. However after this point, as email notifications were turned on by ICHT for all patients, both text and/or email interventions will be analysed.

Inclusion Criteria:

• All patients who have been referred to their first outpatient appointment at one of five ICHT adult clinical specialties - Cardiology, Colorectal Surgery, Gastroenterology, Ophthalmology and Plastic Surgery.

Exclusion Criteria:

• Phone or video appointments
• Diagnostics appointments
• Two-week wait appointments
• Saturday or Sunday appointments
• Appointments without message reminders switched on in DrDoctor
• Patients who re-enter the study and receive >1 intervention
• Patients who received email message reminders about their appointment (until 23rd May 2024, after which they will be included due to change in ICHT communications approach)

No individual participant data will be shared with other researchers.