Scientometrics on interventions used for adherence of hypertension and diabetes therapies

ABSTRACT Objective To identify interventions aimed to improve adherence to medical and non-medical antihypertensive and antidiabetic therapy. Methods Scientometric study conducted in February and March 2018, based on data collected on PubMed ® and SciELO databases, using the following search terms: “interventions to improve adherence to diabetes therapy”, “interventions to improve adherence to hypertension therapy” and “interventions to improve adherence to therapy for hypertension and diabetes”. Results A total of 95 articles were selected. Scientific production increased as of 2009, with a higher number of studies published between 2015 and 2017. Most interventions described in literature were aimed at diabetic patients (46.31%). Face-to-face interventions were more common (46.31%), followed by telephone-based (31.58%) and digital (26.31%) interventions. North America stood out as the continent with the highest number of publications (68.42%), followed by Europe (14.74%). Most studies (63.16%) were based on a single type of intervention. Conclusion Traditional intervention methods were more widely used to promote adherence to antihypertensive and antidiabetic therapy; digital technology emerged as a trend in interventions aimed to improve hypertension and diabetes-related health behaviors.


❚ INTRODUCTION
Hypertension and diabetes mellitus are among the major causes of death due to non-communicable chronic diseases (NCDs) worldwide, with a global prevalence of 22% in hypertensive individuals, and approximately 9.4 million related deaths per year. (1) Global prevalence in diabetic individuals is roughly 9%, with more than 1.5 million related deaths annually. (2) In these settings, adherence to medical and non-medical treatment of hypertension and diabetes is a major challenge in health promotion. (3) The rate of hypertension-and diabetes-related complications is constantly on the rise in middle-and low-income countries. This is partly due to population aging and the need to adopt a healthy lifestyle. (1) Lack of adherence to treatment is a major public health concern, with half of patients failing to comply with medical prescriptions. (4) Antihypertensive and antidiabetic drugs are recommended only when nonmedical interventions, such as dietary management, regular physical activity, and other practices associated with a healthy lifestyle have failed. (5) Measures adopted to tackle NCDs have defined policies and actions worldwide. (6) Studies investigating adherence to treatment have revealed pathways for the development of innovative strategies and behavioral interventions, aimed to support proper monitoring of prescribed therapies, with improved quality of life for patients. (4) Interventions consist of health promotion actions leading to individual or collective behavior changes, according to the social context in which each individual is inserted, with a view to improving adherence to NCD therapy. (7) A wide array of interventions can assist healthcare managers and services in NCD control, ranging from traditional methods, such as home visits and individual or group counselling, to technologybased approaches employed to send reminders or deliver content associated with health promotion. (8) ❚ OBJECTIVE To describe the state-of-the-art of scientific publications related to the development of interventions aimed to improve adherence to antihypertensive and antidiabetic therapy.
PubMed ® database search was conducted using the following search terms: "interventions to improve adherence to diabetes therapy", "interventions to improve adherence to hypertension therapy" and "interventions to improve adherence to therapy for hypertension and diabetes". SciELO database was searched using the following search terms: "intervenções para melhorar a adesão à terapia do diabetes", "intervenções para melhorar a adesão à terapia de hipertensão" and "intervenções para melhorar a adesão à terapia da hipertensão e diabetes".
Literature review and systematic literature review articles were excluded, and only original articles were selected for increased precision. Titles and abstracts were analyzed, and the articles classified under seven headings according to intervention type, as follows: face-to-face intervention, telephone-based intervention, digital intervention, indirect intervention, health education intervention, postal intervention or financial incentive intervention.
Data were entered into spreadsheets (Excel 2016) and tabulated according to year of publication, type of disease or target-audience, type of intervention, number of publications per continent and number of interventions per study.

❚ RESULTS
Database search using selected terms yielded 600 publications in PubMed ® and none in SciELO, between 2000 and 2018. Of these, 95 articles were selected following title and abstract analysis ( Table 1 -Appendix  1). Articles failing to meet inclusion criteria (505) were excluded.
Data analysis revealed scientific production growth as of 2009, with a higher volume of publications describing interventions aimed to improve adherence to antihypertensive and antidiabetic therapy, between 2015 and 2017 ( Figure 1).
Interventions were defined as follows: (1) faceto-face -individual appointments in clinics and home visits by health professionals; (2) telephone-basedwhenever conducted over the telephone; (3) digital -SMS text messages, Apps or software (WhatsApp, etc.); (4) indirect -public policies, audits, guidelines and professional training; (5) health education -talks and orientations given to patients; (6) postal -letters sent  Article distribution according to continent of origin revealed larger numbers of studies conducted in North America (68.4%; n=65) or Europe (14.8%; n=14), with only a small proportion (3.1%; n=3) from South America.

❚ DISCUSSION
In this study, the findings derived from the analysis of scientific publications emphasize the importance of the topic selected in the realm of public policies aimed at health promotion, as shown by adoption of control measures by several counties in the face of increased prevalence of hypertension and diabetes. (9) This process has led to the application of different interventions resulting in clinical improvement of patients and lower health care costs. (10) The World Health Organization (WHO), driven by some countries, such as the United States, Canada, Australia and the United Kingdom, expected to reduce mortality rates associated with chronic diseases by 2% per year, up to 2015. (11) With these estimates in mind, joint efforts by the WHO, governments, world organizations and the private sector approved the Global Action Plan for the Prevention and Control of NCDs 2013-2020. The WHO has also set voluntary targets for 2025, among which the reduction of premature mortality due to these diseases by 25%. (1) The higher number of scientific publications on interventions in the last decade may reflect population aging, given physiological changes tend to increase with age, leading to higher prevalence of NCDs. (12) Improved basic health care, growing urbanization, global commercialization of health harming products, and adoption of unhealthy life styles may have boosted scientific production during this period. (2) Hypertension is a silent disease affecting individuals of all socioeconomic levels, with higher mortality and global prevalence rates compared to other NCDs; (5) still, studies investigating interventions aimed at diabetic patients are even more abundant. This may be explained by the diversity of acute and chronic complications associated with diabetes mellitus and the two-to threefold increase in health costs over the years as compared to costs associated with non-diabetic patients. (2) In 2017, estimated global costs of diabetes amounted to US$ 850 billion, with significant social and economic impacts on healthcare systems. (2) As regards different types of interventions promoting adherence to medical and non-medical antihypertensive and antidiabetic therapy, face-to-face interventions consisting of individual appointments and home visits were more commonly described in scientific literature. (13) Individual appointments are widely used in outpatient services, clinics, community pharmacies, multidisciplinary health teams (14) and other health centers, since they represent traditional methods involving joint analysis of barriers to adherence to therapy, and solutions for improved health outcomes, by physicians, pharmacists, nurses, psychologists, dietitians, physical educators and patients. (15) Telephone-based interventions also proved to be efficient, since these encourage patients with several comorbidities to adopt best care practices via telephone call monitoring. (16) This type of traditional intervention is widely used by pharmacists in community pharmacies and clinics; as drug managers, pharmacists provide guidance to patients regarding health behaviors, thereby contributing to improved adherence to medical and nonmedical antihypertensive and antidiabetic therapy. (17) Telephone-based services constitute more accessible alternatives, with reduced medical appointment load, lower transportation costs for low-income patients and the added benefit of proposing the insertion of personalized information. (18) Digital interventions consisting of SMS text messages, Web, apps and WhatsApp have been attracting increasing attention in studies investigating adherence to treatment over the last few years. Such technology tools facilitate access to health information aimed to improve patients' quality of life. (19) One study has shown that combined technologies may encourage health behavior changes and increase adherence to antihypertensive and antidiabetic therapy. (20) Digital interventions were shown to be particularly effective in underdeveloped and developing countries, for ensuring access to health benefits from remote areas worldwide via widely available technology. (21) Mobile health tools, or m-Health, are a major trend in NCD control, given their low cost and ability to provide remote health care. (22) Other interventions designed to improve health behavior in hypertensive and diabetic patients described in literature include indirect interventions, comprising public policies, health guidelines, audits and professional training. (23) Health education interventions are often implemented by nurses and other health professionals by means of talks and group guidance sessions, particularly in communities where technological resources are limited or lacking. (24) Studies describing postal interventions, consisting of letters containing health recommendations were scarce. (25) Finally, financial incentive interventions einstein (São Paulo). 2020;18:1-11 applied by some health services, particularly the private sector, to encourage patient adherence out of financial compensation, were seldom described. (26) As regards study origin, most scientific research related to interventions tailored to hypertensive and diabetic individuals were conducted in North America, followed by European countries. In the United States, for example, one in every three individuals, or 75.2 million American citizens suffer from hypertension, and almost half this population (35 million people) has blood pressure levels above recommendations. (27) From 2011 to 2014, the US hypertension prevalence averaged 34% (34.5% and 33.4%, in men and women respectively); prevalence in the elderly population was 67.2%, with approximately 410,624 deaths due to primary or secondary causes, and a total cost of US$ 51.2 billion between 2012 and 2013. (28) Diabetes affected approximately 30.3 million Americans in 2015, with 9.4% prevalence. Diabetes was the seventh cause of death in the country, with more than 252,806 deaths resulting directly or indirectly from the disease, annually. (29) In 2017, total diabetes costs amounted to US$ 327 billion, with individuals aged 65 years or older accounting for most of the financial burden, and driving rising healthcare budget requirements. (2) The 2010 estimated prevalence of diagnosed and undiagnosed diabetes in the adult population of 14% is expected increase to 21% up to 2050. (30) Obesity is a major factor in the growing prevalence of other NCDs and has been associated with rising numbers of premature deaths due to hypertension and diabetes, particularly in countries such as the United States, where consumption of industrialized foods is high. Poor dietary habits resulted in 17% prevalence of obesity among children, and approximately one-third of the adult population (36.5%) affected between 2011 and 2014, particularly middle-aged individuals (40 to 59 years). (29) The number of studies on interventions conducted in European countries has also increased. Population aging in these countries has led to a constant rise in NCD prevalence and sparked interest in strategies aimed at reducing the burden of health care costs. (31) In South America, a continent comprising developing countries, studies investigating interventions aimed to increase adherence to antihypertensive and antidiabetic therapy are quite recent, and in lesser numbers compared to North America. In Brazil, improved health status and increased life expectancy translated into 18% growth of the aging population over the last 5 years, from 25.4 million in 2012, to 30 million in 2017. These factors contributed to growing estimated NCD prevalence over the course of one decade, with 14.2% increase in hypertension prevalence (from 22.5% to 25.7%, between 2006 and 2016) and 61.8% increase in diabetes prevalence (from 5.5% to 8.9%, between 2006 and 2016). (32) High NCD prevalence in 2015 led to 424,058 deaths due to cardiovascular diseases, and 62,466 deaths due to diabetes, (33) with total costs amounting to US$ 4.18 and US$ 22 billion, respectively. (6,9) Over the last few years, lifestyle changes among Brazilian citizens have had significant impacts on obesity-related comorbidity rates, another important risk-factor for hypertension and diabetes. (5) Obesity rates increased 60% in Brazil in 10 years, from 11.8% in 2006 to 18.9% in 2016, with higher prevalence (22.9%) among individuals aged 55 to 64 years. (32) Brazil has adopted important measures to tackle NCDs over the last few years, such as establishing the Sistema de Vigilância de Doenças Crônicas Não Transmissíveis (VIGITEL) [Surveillance System for Non-communicable Chronic Diseases], for permanent monitoring of chronic diseases and assessment of the best intervention strategies. (32) Creation of Plano de Ações para o Enfrentamento de DCNT 2011-2022 [Action Plan to Tackle NCDs 2011-2022] was another important measure encouraging the development of public policies aimed at health promotion, with significant contributions to the achievement of goals, such as 2% annual reduction in premature deaths due to NCDs until 2022, (6) so as to ensure sustainable health development for the 2030 Agenda. (34) Studies based on a single type of intervention were more common. In many countries, healthcare provision to elderly patients with two or more comorbidities poses a greater challenge to managers and health professionals. Interventions aimed to increase adherence to treatment require guidelines focused on incentives for patients in this age group. (35) In the United States, delivery of multiple interventions to the same patient failed to improve health outcomes due to diseasespecific requirements and higher costs. Therefore, comprehensive tools focused on patient quality of life rather than disease alone must be sought after. (35) ❚ CONCLUSION This scientometric study revealed significant gaps. The number of studies conducted in Latin America, particularly in Brazil, was small, in contrast with the growing prevalence of hypertension and diabetes in einstein (São Paulo). 2020;18:1-11 the country and the Latin American continent overall. Financial incentive interventions were limited to some developed countries; still, despite limited evidence, this type of intervention may be a promising strategy for behavior change promotion. Studies investigating interventions designed to improve adherence to treatment by patients with comorbidities, such as hypertension and diabetes, were scarce.
Finally, traditional interventions such as face-toface interviews or telephone calls were more commonly used to encourage adherence to antihypertensive and antidiabetic therapy, in spite of the current trend of digital technology application to leverage health behavior changes.