Evaluation of the International Diffusion of the European Code Against Cancer (ECAC) Through Mobile Telephony. CECC-WHO Study

A type-2 hybrid effectiveness-implementation study was designed to primarily test the impact of a mHealth implementation strategy on implementation outcomes (e.g., adoption, fidelity of intervention delivery) while simultaneously gathering information on the effectiveness of the intervention. The feasibility single-blind randomised controlled trial has been carried out on a sample of the general population in the Autonomous Community of Andalusia, the most populated region of Spain, with more than 8.5 million residents (17.9%). The Andalusian Health Service (SAS, acronym in Spanish) is the main healthcare provider of the Andalusian Public Health System (SSPA, acronym in Spanish), part of the decentralised Spanish National Health System, which provides free universal health insurance. The SAS oversees "Salud Responde" (SR, acronym in Spanish), a multi-channel platform that provides a broad online portfolio of services to respond to health-related issues and administrative management needs of citizens and health professionals, complementing the care provided by the health care units. It allows 24 hours a day access to the services and benefits of the SSPA, from any point in Andalusia, through telephone, e-mail, short message system (SMS) and a mobile application (app) to manage appointments and reminders, and to disseminate personalized health information. The app has a high coverage with more than 5.7 million users (67% of the Andalusian's population) registered in its system in 2023; yet the SR platform maintains the information system service via SMS for specific campaigns to those users who do not have or want the app installed on their mobile phone (around 9700 registered users).

The inclusion criteria were being 18 years or over, being entitled to health care benefits in SSPA, having a mobile phone, and being able to read messages on them. A sample of 1991 users from the User Database (BDU, in Spanish) of the SSPA, that in 2019 included more than 8.5 million users (REF), was used to randomly assign subjects to the different groups. The first randomization was performed according to the recruitment procedure (users registered or not in the SR platform) and the technology used to disseminate the messages (app or SMS). Group 1 (G1), subjects registered in the SR app service platform, and Group 2 (G2) subjects registered in the SR SMS service platform, were recruited through phone call. The rest of subjects needed to reach the target sample size were recruited from those included in the BDU database through a phone call. A maximum of eight attempts were done before considering no response. To be able to calculate participation rate (positive response rate + acceptance to participate), no replacement was performed.

For those not registered in the SR platform who accepted to participate in the study, a further distribution was done based on a discriminatory question: those users with internet connection in their mobile phone both through 3G/4G and Wi-Fi were allocated in Group 3 (G3) and encouraged to download the app to receive messages, and those without internet were allocated in Group 4 (G4) to receive messages by SMS. Informed consent to participate was requested for tehe investigators and the voluntary and anonymous nature of the participation was ensured. The simple randomisation to the different study groups was performed using the EPIDAT 4.0 programme. The second randomization was performed based on the messages' delivery frequency: frequency of 2 SMS or 2 app notifications ("push") per week, or frequency of 7 SMS or 7 app notifications per week.

Intervention After the second randomisation, an intervention was conducted for 4 weeks where participants were sent app push notifications or SMS messages via the SR platform. Each push notification or SMS message included a cancer prevention recommendation from the ECAC 4th edition (in Spanish) from the following list: "Don't smoke. Do not use any type of tobacco"; "Maintain a healthy weight"; "Exercise daily. Limit time spent sitting"; "Eat lots of whole grains, legumes, fruits and vegetables"; "Limit high-calorie foods (foods rich in sugar or fat) and avoid sugary drinks"; "Avoid processed meat; limit consumption of red meat and salt-rich foods"; "Limit alcohol consumption, although it is best for cancer prevention to avoid alcoholic beverages"; and the URL link to visit the Spanish version of the ECAC's website to consult additional information, through the mobile phone or other digital device. All messages were endorsed and signed by the Head of the Andalusian Regional Ministry of Health.

Data collection was conducted for the investigators at two time points: at baseline during the recruitment call, a pre-intervention survey was performed to gather basic socio-demographic and patterns of use of new technologies (e.g., type of mobile device, internet access from phone or computer, etc.); at the end of the intervention, from one week to one month after receiving the last message, a post-intervention survey was carried out by telephone to all participants.