Instant Message-guided Hypertension Management Intervention Among Stroke Survivors

Intervention group: Participants in intervention group will receive the EMI for 4 weeks. Based on the steps of mobile message development recommended by Abroms, et al., we will develop a message content library and protocol for EMI delivery. 1. Message contents: The message content library will consist of two parts: 1. brief stroke and hypertension education messages (mandatory), and 2. lifestyle modification messages (optional). 2. Message delivery * Regular messages: The messages in the two parts will be sent regularly to each participant. As personalisation is a core process subject to behavioural changes, the content, frequency, and timing of the messages will be determined based on participants' preferences. To save labour and increase efficiency, we will develop a message 'scheduler' program. We will pre-set the message scheduler, which will then automatically send out content to participants according to their preferences. The development of the program is highly useful particularly in cases which participants prefer to receive messages during non-office hours. * Nurse-led real-time support messages (chat-type): Chat-based nurse support will be given to the participants as an extension of the regular messages. However, the participants will be informed beforehand that the nurse will only play a supportive role and will not provide formal care. The number of the chat messages will not be limited, but the nurse-led real-time support messages will only be provided during working hours (i.e., 9am-6pm) on weekdays to limit the nurse RA's workload. Control Group: The control group will receive one instant message about general stroke management including hypertension management from the Hospital Authority of HK SAR Government website (https://www21.ha.org.hk/smartpatient/SPW/en-US/Disease-Information/Disease/?guid=29ac1219-3d68-4378-a2bd-09e111da3650), which is open to the public.