لخّصلي

hypertension (HTN) is one of the most important
JLmodifiable risk factors for cardiovascular disease.!")
In 2014, its prevalence among people over 18 years was 22% and it is expected to reach 1.656 billion by 2025, [2)
HTN is called the silent killer due to the absence of obvious symptoms and its high death rate."] It is associated with many different health problems including stroke, heart attack, congestive heart failure, pulmonary edema, kidney failure, visual problems, obesity, chronic cardiovascular disease, and death, B4] In 2009, the World
Health Organization attributed 13% of all deaths in the world to HTN 2)
Despite the increasing level of public health-related knowledge, poor adherence to the treatments of chronic diseases such as HTN is still a global problem. According to the World Health Organization, the prevalence of poor treatment adherence is 50%, on average. Poor treatment adherence is also common among patients with HTNI
Poor treatment adherence is associated with many different health problems such as increased risk for cerebrovascular and coronary diseases, 151 increased rate of hospital readmission, 9 limited treatment success, and ineffective disease control. A study reported that more than 30% of hospital readmissions are due to poor treatment adherence. lo The most important factors affecting treatment adherence include forgetfulness, high costs of medications, lack of knowledge, low quality of life, lack of obvious disease symnptoms,8) demographic characteristics, perceptual and social factors, quality of healthcare providers' interactions with patients, characteristics of healthcare systems, patients general health status, and their degree of involvement in treatments l Understanding these factors plays an important role in the development of interventions for promoting treatment adherence and recovery,9)
Improving patients' knowledge is one of the basic nursing strategies for promoting their treatment adherence.
Knowledge improvement promotes treatment adherence, facilitates HTN management,[10) encourages patient involvement in the treatment process and self-care, and reduces hospital readmission rate [l1.12) Health information technology, including mobile phone, can be used for patient education. 13) Mobile phone technology can be used to promote health, prevent disease spread, improve self-management, provide medical counseling, and provide medication reminders.4 The widespread use of mobile phone for health-related purposes has resulted in the development of a term called mobile health, which involves the use of various mobile phone features such as text and video messaging, voice calling,and Internet-based messaging in health-care delivery. 1s]
Studies showed that this technology helped to reduce the annual maternal and neonatal deaths by 40,000 in
Bangladesh, 75,000 in India, and 290,000 in Pakistan and can help to treat tuberculosis by 50,000 cases in
Russia, 40,000 cases in Thailand, and 10,000 cases in
Malaysia.19) Moreover, this technology has reduced the annual cost of care delivery to elderly people by around five million Euros in Europe (16]
Text messaging is one of the features of mobile phones.
As a simple and inexpensive feature, text messaging is available on all mobile phones. Its use is simple and does not need extraordinary skills, and hence, it can be used for different health-care-related purposes.
Studies showed that text messaging through mobile phones has significant effects on primary health outcomes l17) outpatient service management (17.18] smoking cessation,8,19) management of medication side effects, 9.17 and improvement of medication use by patients with physical and behavioral problems, 9.1721|
It also has beneficial effects on medication use among patients with chronic conditions such as diabetes mellitus, chronic renal failure, thalassemia major, and valvular heart disease. 2223] Yet, there are controversies over the effects of text messaging through mobile phones. For instance, a systematic review reported that three studies found interventions based on short message service (SMS) effective in improving HTN management, while three studies found its insignificant effects on HTN management. (24) Moreover, a study found that although an automated adherence support program based on text messaging could reduce blood pressure among adults with HTN, there was no evidence that an interactive intervention can also produce this effect.(25) Besides, most previous studies into the effects of text messaging on HTN outcomes used questionnaires such as the Morisky Medication Adherence Scale and Brief Medication Questionnaire for adherence assessment. These instruments solely measure adherence to medications and provide no information about the other aspects of treatment adherence 29) Moreover, adherence-related interventions in previous studies were mostly implemented in short periods of time !7192027 In addition, previous studies did not compare the effects of interactive and noninteractive text messaging on HTN outcomes. Consequently, the present study was designed and conducted to address these gaps.