The Effectiveness of Text Message-based Rehabilitation Program on Cardiometabolic Risk Factors for Patients With Peripheral Artery Disease Post-surgical Revascularization: A Randomized Controlled Trial

Background Peripheral artery disease (PAD) is a circulatory disease which associated with narrowing of arteries in the lower limbs. It is also a common atherosclerotic vascular disease affecting 3-12% of the global population [1]. With aging of the global population and increasing industrialization, PAD is expected to increase further in the next few decades. Worse of all, PAD increases risk of coronary, cerebrovascular complication including death [2]. So secondary prevention is essential for patients with PAD especially after revascularization.

There is robust evidence that the secondary prevention of peripheral artery disease can be achieved by lifestyle modification [3-4]. The American Heart Association (AHA) recommended that smoking cessation, glycemic control and structured exercise are import elements of care for patient with PAD [5]. Despite the need of secondary prevention and the evidence-based guidelines from AHA, there is no structured rehabilitation program for PAD patients in Hong Kong. Recent studies reported secondary prevention of PAD mainly focus on exercise and medication therapy. However, a single lifestyle behavioral change could not address the needs of the patients who have multiple lifestyle risk factors. Since many PAD patients have more than one lifestyle risk factor, the rehabilitation program targeting multiple lifestyle behavioral changes will be more benefit to the at risk patients.

Mobile-rehabilitation is a new concept to deliver the rehabilitation program. Center-based rehabilitation is well evidenced to reduce mortality, unplanned hospital admissions and improve quality of life and psychological well-being of the patients [6]. However, its benefits is limited by low referral rate and inaccessibility of program site [7]. Mobile phone messaging can be used to motivate and reinforce the lifestyle behavioral changes. It can also prevent patients from relapsing to the previous unhealthy lifestyle behavioral stage. Current studies show a positive result of using texting to promote healthy lifestyle behaviors among adults with cardiovascular disease [8-9]. Considering that the mobile-phone penetration rate in Hong Kong is about 96.1% [10], the use of texting can be an innovative and cost-effective tool to promote a healthy lifestyle and improve quality of life of PAD patients.

To the best of the author's knowledge, there have been no Randomized Controlled Trial (RCT) of a stand-alone mobile phone message-based rehabilitation program designed to help peripheral artery disease patients. This is the first randomized controlled trial to examine the effectiveness of message-based rehabilitation on cardiometabolic risk factors for PAD patients who have received surgical revascularization. The transtheorectical model (TTM) [11] will be used as a framework for conceptualizing the process of behavior change. This model is well-suited to this messaging-based intervention as it allows understanding of participants' processes and dynamics of behavioral changes.

2. Aim This single-blinded randomized controlled trial aimed to evaluate the effectiveness of the message-based rehabilitation on fasting low density lipoprotein (LDL) level, Ankle-Brachial Index (ABI), healthy lifestyle behaviours, quality of life and smoking status for PAD patients who have received revascularization.