Poor diet and physical inactivity account for an estimated 10% of the global disability-adjusted life-years.1 The burden imposed by these risk factors strongly affects the growing epidemic of cardiovascular disease. Worldwide, cardiovascular disease causes 16·7 million deaths each year, 80% of which occur in low-income and middle-income countries.2 Early interventions to increase the practice of healthy lifestyles in individuals who are at high risk of cardiovascular disease can reduce blood pressure, excess bodyweight, and glycaemic impairment and prevent or delay the onset of type 2 diabetes and hypertension.3, 4, 5, 6, 7 Prehypertension (defined as systolic blood pressure of 120–139 mm Hg or diastolic blood pressure of 80–89 mm Hg) is associated with an increased probability of cardiovascular events, with a progression rate to hypertension of 10–20% per year.8, 9
Research in context
Evidence before this study
Early interventions to increase the adoption of healthy lifestyles in high-risk individuals can reduce blood pressure, excess bodyweight, and glycaemia, helping to prevent type 2 diabetes and hypertension or delay their onset. Evidence-based guidelines advocate for specific lifestyle modifications in populations at high risk of cardiovascular disease. However, few high-quality trials of lifestyle interventions aimed at reducing cardiovascular disease risk have been done in countries in Latin America or other low-income and middle-income countries worldwide, despite robust evidence in support of the effectiveness of these measures. With the rapid growth of mobile phone use in developing countries, mobile phone-based health interventions (mHealth) are emerging as a useful approach to bolster health-care systems with an overburdened workforce, limited financial resources, and an increasing prevalence of chronic diseases. This type of intervention has been shown to promote behavioural changes, leading to effects such as weight loss and increased physical activity, but the evidence is mixed, especially for long-term effects, and very few studies have been done in low-income and middle-income countries or low-resource settings.
Added value of this study
To our knowledge, this is the first randomised controlled trial to assess an mHealth intervention that aims to promote healthy lifestyle behaviours in individuals in Latin America who are at high risk of developing cardiovascular disease. 12 months of intervention did not result in a change in blood pressure (the primary outcome measure), but did lead to a modest reduction in bodyweight and an improvement in diet quality.
Implications of all the available evidence
Our results, although modest, are encouraging and fill an important research gap on the effect of mobile phone-based interventions on behavioural risk factors for the prevention of cardiovascular disease in low-income and middle-income countries. However, more research is needed, particularly in populations from low-resource settings in low-income and middle-income countries, which are disproportionally affected by the epidemic of chronic diseases.
Evidence-based guidelines advocate for specific lifestyle modifications in populations with high risk of cardiovascular disease.10 However, few trials to test lifestyle interventions for the reduction of cardiovascular disease risk have been done in Latin America or in low-income and middle-income countries, despite robust evidence of their effectiveness.11, 12, 13 Health promotion is shifting towards new delivery modes of preventive care, such as mobile phone-based health interventions (mHealth) that rely on telecommunication and multimedia technologies, intended to be able to reach a large population effectively.14, 15, 16 Yet, evidence in favour of mHealth for lifestyle modification is inconclusive17 and is mostly restricted to trials done in high-income countries.18, 19
With the rapid rise in mobile phone use in low-income and middle-income countries, mHealth could become a useful way to address several health-care system constraints in these countries, such as the small and overburdened health-care workforce, limited financial resources, and an increasing prevalence of chronic diseases. In view of these constraints, the extension of health care to difficult-to-reach populations is challenging.20 Strategies that depend on either mobile phone calls or text messaging have been shown to improve patient–provider communication, encourage behaviour change, and assist in chronic disease management.21, 22, 23, 24 Interventions based on phone calls and text messages have also been shown to promote weight loss and increase physical activity.21, 25 In a systematic review26 use of text messages for preventive health care was found to improve health status and health behaviour, but the evidence is mixed, especially with respect to the long-term effectiveness of such interventions. Interestingly, results of a study27 of tailored text messages to prevent the onset of type 2 diabetes in patients with glucose impairment in India showed a significant reduction in incidence after 2 years of follow-up. However, almost all of the 75 trials that have assessed the use of mHealth to improve disease management or change health behaviours were done in high-income countries.28 In fact, in one systematic review,24 only nine of the trials included in the analysis were from low-income or middle-income countries, and in another review29 a few high-quality studies in less developed countries were identified, mostly from middle-income countries.
Chronic disorders and their risk factors are now the major causes of death, disability, and illness in Latin America.1 In 2004, cardiovascular disease was the cause of about 35% of all deaths and 68% of the total disease burden.30 Health systems in most Latin American countries perform poorly on measures of effectiveness and quality of care for patients with cardiovascular disease, and primary care systems in the region do not usually have preventive programmes for people who are at high risk of cardiovascular disease.31
In this study, we aimed to investigate whether mHealth that included monthly counselling phone calls and customised text messages containing advice for lifestyle modification could reduce blood pressure and prevent progression to hypertension, promote weight loss, and improve diet quality and physical activity in adults with prehypertension living in low-resource urban settings in Argentina, Guatemala, and Peru.