TElemedicine to Replace Face-to-face Physician Consultation in Patients With HyperTension : a Pilot Randomized-controlled Trial

Inclusion Criteria: * have a diagnosis of essential hypertension (HT) and are currently taking antihypertensive agents * have good control of clinic BP as confirmed on ambulatory blood pressure monitoring (ABPM) (daytime BP ≤135/85mmHg) * can read basic Chinese (as the content of the app in Chinese) * have a home BP monitor (HBPM) * used any mobile app (not HT-related) in the previous 1 year Exclusion Criteria: * an inability to give informed consent * unwillingness to conduct HBPM or repeated ABPM * current use of any other HT app for BP monitoring * relative contraindications to ABPM (diagnosed atrial fibrillation, occupational drivers or patients with bleeding tendencies) * severe mental illness, including those diagnosed with schizophrenia, dementia or as being actively suicidal, because these patients may have diminished ability to use the HT app; * a diagnosis of other chronic disease(s) that need regular physical assessments and doctors' consultations (e.g. diabetes and asthma that are being treated, but patients with hypertension and hyperlipidaemia will remain eligible) * diagnosed active cancer,