Applicability of the current hypertension guidelines in Latin America

Introduction

Cardiovascular disease (CVD) is the main cause of death in the world. Every year more people die from CVD than from any other disease. Globally, CVD accounts for approximately 17.5 million deaths per year, which is almost one-third of the total (31%) annual number of deaths [World Health Organization, 2015]. Approximately three-quarters of these deaths occur in low-to-medium developed countries; 25% of all annual deaths in the Latin American and Caribbean (LAC) region are due to CVD [Lozano et al. 2012]. The rate of occurrence of CVD among Hispanics living in the US is alarming and represents the most likely cause of death among this population (about 31% of all deaths). The prevalence in the US of heart disease is 8.1% in Hispanics and 12.1% in Caucasians. Moreover, the prevalence of obesity, diabetes mellitus, hypertension and dyslipidemia is generally higher among Hispanics than Caucasians [American Heart Association, 2009].

The sustained and progressive elevation of blood pressure is the most common modifiable factor in the development of CVD. The progressive elevation of systolic blood pressure in aging appears to be a common condition in modern societies. Furthermore, the frequency of hypertensive diagnoses (>140/90 mm Hg) increases with age in all world populations [World Health Organization, 2013]. Different rates of increasing blood pressure are critical in the risk for severe health complications, which are determined epidemiologically as the threshold to hypertension (140/90 mm Hg). The complex and varied exposure to different types of economic and psychosocial factors affects the prevalence of hypertension at different ages and its distribution among different social and economic strata [Chow et al. 2013].

Hypertension is the greatest risk factor for CVD, which is the most important cause of premature death, over dyslipidemia, smoking, overweight, obesity and physical inactivity [Bromfield and Muntner, 2013]. At least 970 million people worldwide have hypertension, about 330 million people in the developed world and around 640 million in the developing world. Hypertension is responsible for at least 45% of total ischemic heart disease mortality and 51% of total stroke mortality [World Health Organization, 2013].

Cardiac mortality rates continue to rise in most LAC countries. In LAC countries where rates have declined, this trend has been considerably lower than that recorded in the US. In addition, a recent study suggests that the rising incidence of high blood pressure might be the reason [Rasolt, 2014]. Moreover, the lack of data on the distribution of risk factors and their impact on the incidence of CVD and mortality has hampered efforts to control the epidemic of CVD in the LAC region. This is reflected in very low rates of awareness, treatment and achieved goals.

The social and economic effects of the inadequate treatment of hypertension are high. Traditionally, the first step in solving the problem of low efficiency, effectiveness and equity in handling problems such as hypertension has been to develop clinical practice guidelines based on evidence.

Pertinence of evidence-based guidelines for the diagnosis and control of hypertension

Medical practice is carried out in a field in which there is a high degree of uncertainty (i.e. how likely is it that a fact that is accepted as true is really true). Evidence-based medicine [Evidence-Based Medicine Working Group, 1992] has been accepted as an appropriate approach to reducing uncertainty in medical practice. Moreover, the best available approach to improving medical practice is the development of evidence-based guidelines for the diagnosis and control of hypertension.

Clinical guidelines are systematically developed statements designed to help practitioners and patients decide on healthcare that is appropriate to specific clinical conditions and/or circumstances. These guidelines are intended to tie clinical practice to scientific standards of evidence, instead of depending solely on the physician’s accumulated personal experience to determine the clinical techniques that are the most effective. The guidelines also provide a means of measuring the efficacy of those practices.

The guidelines are generally intended to serve as a bridge from the evidence, which by definition is obtained from studies related to comparisons of averages and dispersion, and its application to a particular patient. The application of standards has been considered a panacea for the problems of rising costs, inequity and variability. However, a main disadvantage of this concept is that averages can obscure differences between and within countries, as well as between and within classes, races and ethnic groups.

Is it appropriate and/or necessary to tailor guidelines only according to countries or geographical regions?

Clinical practice guidelines for regulating medical activities have traditionally been developed for a specific country or a particular region. Consequently, there are international, regional and national guidelines for the control of hypertension.

Traditionally, nationality has been the most common variable used to explain inequalities in health systems. Based on this concept, the World Bank has proposed dividing the world into discrete regions [World Bank, 2015a], which has clear implications for overriding socioeconomic and cultural differences. The proposed system could be very useful, especially in public health. In daily medical practice, however, the application of guidelines that were developed with a national or regional focus may sometimes be inappropriate.

However, explaining the differences in health status according to nationality results in a restricted view of the problem. Because a nation is rarely homogeneous in its ethnic, social, cultural and economic aspects, these factors, not nationality, are the main variables of differences in health status among humans. Traditionally, only differences between countries and regions have been considered on the assumption that the inhabitants of a country or region are homogenous. In areas such as the LAC region, which has high ethnic diversity as well as social asymmetries and inequalities in living conditions, opportunities, economic status, education, customs and even language, it seems inappropriate to classify the population according to the country or region in which they live. Two people with different nationalities living in similar cultural, educational and economic conditions are more similar than those of same nationality but living in different social and economic strata.

Another important limitation of the current guidelines is that strategies for the clinical management of cardiovascular risk factors are elaborated from a traditional view of the health and disease process. Hence, a separate strategy is specified for each risk factor (e.g. obesity, diabetes, hypertension, hyperlipidemia) rather than thinking in holistic terms of the prevention of CVD. Because the risk factors rarely present in isolation, multi-intervention programs are more effective than an isolated risk-factor strategy. It has been shown that a strategy for treating those at high absolute risk in various regions of the world was less expensive and saved more lives than a strategy based on the target levels of individual risk factors [Murray et al. 2003].

Similarities and differences in the LAC region

The LAC region is not uniform but extremely diverse. Indeed, some researchers have questioned whether there really is a region that could be called the LAC [Inglehart and Carballo, 1997]. However, the LAC region exists as a continent, as a geopolitical mass, as a historic entity, and as a cultural, linguistic and religious reality.

The LAC region is a large territory comprised of countries that are identified by their use of the Spanish and Portuguese languages. It includes most of the Americas, including Mexico and Central America, South America and the Spanish-speaking Caribbean. The geographical area of this territory exceeds 21 million square miles and its population (one of the largest on the planet) is 594.6 million inhabitants. Another 40 million Hispanics live in the US, which constitutes the largest minority (16%) in that country.

In 2013, the urban population of the LAC region was 79%, the gross national income (GNI) was 5.657 trillion United States dollars (USD) and the GNI per capita was USD 9536. The life expectancy at birth in the region is 74 years [World Bank, 2015b]. The population dynamics in the LAC region are extensive, and averages can obscure the differences between and within countries as well as among classes, races and ethnic groups. For example, in the Americas, life expectancy has increased over the past two decades; however, there is an 18-year difference between Costa Rica, where life expectancy at birth is now 77.7 years, and Haiti where it is 59.7 years. The GNI per capita varies from USD 810 in Haiti to USD 9940 in Mexico.

Health disparities within countries can also be great. In the LAC region, there are striking differences in health risks and outcomes between the poorest and the richest, both between and within countries. The population at higher risk uses public sector facilities, which have constrained resources, whereas the population at lower risk uses private sector facilities, which have access to ‘state of the art’ technology and therapeutics. In Bolivia, for example, 97.9% of the people in the highest income quintile have access to healthcare services, but in the lowest quintile, only 19.8% have access. In Peru, 96.7% of the highest income quintile has access to healthcare services, compared with 14.3% in the lowest income quintile. In Guatemala, 91.5% and 9.3% of the highest and lowest income quintiles, respectively, have access to healthcare services.

The Latin American Consortium of Studies in Obesity (LASO) compares major cardiovascular risk factors in the LAC region with those in the US by using individual level patient data pooled from population-based surveys (1998–2007, n = 31,009), 8 LAC countries and a national survey of the US population (1999–2004). The average prevalence of hypertension in the LAC region was 20.2% [95% confidence interval (CI): 12.5–31.0], but it varied considerably with age. Overall, men were hypertensive more often than women were (21.1 versus 19.4%, specifically among younger individuals). Argentina had a low prevalence of hypertension, while high rates of hypertension were seen in Chile, Colombia and Costa Rica. Peru showed a low prevalence of hypertension and diabetes, while in Puerto Rico, diabetes was the most prevalent. Chile tended to show a higher prevalence of each risk factor than in the entire LAC region. However, the prevalence was generally lower in Peru. The largest difference between the US and the LAC region was the lower prevalence of obesity (42%) and lower high-density lipoprotein cholesterol (HDL-C) in Latin Americans (63%) [Miranda et al. 2013].

The FRICAL study [Ciruzzi et al. 2003] was conducted in four LAC countries. The cases and controls were mostly middle class. The results showed large differences in the determinants of myocardial infarction. The Diabetes Mellitus (DM) was very important in Mexico but not in Cuba. In contrast, hypercholesterolemia was very important in Cuba but unimportant in Mexico. These findings suggest that national differences may remain high even in populations with similar socioeconomic status.

Hypertension economics in the LAC region

Economic changes impose a heavy economic burden on health systems in the medium and long terms. To date, few detailed studies have addressed the financial consequences of epidemiological changes in hypertension in Latin America [Arredondo and Zuñiga, 2012]. Moreover, hypertension has economic implications at both the micro-economic and macro-economic levels. It is probably the most important health burden in terms of quality-adjusted life years (Alcocer and Cueto, 2008).

In 2001, the cost to treat and control nonoptimal blood pressure accounted for nearly 10% of the world’s total expenditures on healthcare. The direct and indirect costs of hypertension were estimated to consume 5–15% of the gross domestic product (GDP) in high income countries. In 2007, the estimated direct and indirect costs related to treating hypertension in the LAC were roughly USD 1.2 billion and USD 1.3 billion, respectively.

In 2001, hypertension global world cost was USD 372 billion. In the LAC region in the same year, indirect healthcare costs attributable to hypertension were USD 10.6 billion. If blood pressure levels remain unchanged, healthcare costs over the next 10 years are predicted to reach USD 1 trillion globally, including USD 43 billion in the LAC region [Gaziano et al. 2009; Alcocer and Cueto, 2008].

The problem of information about hypertension in the LAC region

A major problem in formulating guidelines for the LAC region, as well as in adopting the recommendations for diagnosis and treatment of hypertension, is that accurate information is required about the possible differences in the hypertensive process throughout the region. Information on the distribution of cardiovascular risk factors in the LAC region is sparse and scattered, not only due to technical limitations but also the existence of considerable variations in the prevalence of hypertension reported among different countries.

In a recent study, Burroughs-Peña and colleagues reviewed the literature on the prevalence of hypertension in the LAC region, as referenced in MEDLINE and the Latin American and Caribbean Health Science Literature Database (LILACS) [Burroughs-Peña et al. 2012]. Using a critical appraisal tool, they evaluated the methodology of each study and found that, from 2001 to 2010, 81 papers were published on the prevalence of hypertension in the LAC region. Only 24 of these studies met the minimum methodological criteria for evaluation. Moreover, less than 46% of the published studies reported rates of awareness, treatment and control of hypertension. Estimates of hypertension prevalence ranged from 7% to 49%. They concluded that: ‘These studies were primarily done in urban centers and are not evenly distributed throughout the region. The quality and geographic distribution of the published literature on the prevalence of hypertension in Latin America and the Caribbean are inadequate’ [Burroughs-Peña et al. 2012].

The case of Mexico illustrates the lack of clarity in the existing information. The CARMELA survey, a cross-sectional, epidemiologic study assessing cardiovascular risk factors using stratified multistage sampling of adult populations, found that the prevalence of hypertension in Mexico City was 11.7% [Hernández-Hernández et al. 2010]. In contrast, ENSANUT 2012, a national state-of-the-art survey conducted by the Mexican government, found that the national prevalence of hypertension was 31.5%, of which 31% was in Mexico City [Campos-Nonato et al. 2013]. Moreover, in a prior Mexican survey (ENSANUT 2006) performed around the same time as CARMELA, the reported frequency of hypertension was 31.6% [Barquera et al. 2010]. In a sample of 2602 middle class urban subjects in Mexico City, the frequency of hypertension was 32% [Meaney et al. 2013], which is similar to the percentage found in the ENSANUT survey but almost three times higher than in the CARMELA study.

Hypertension guidelines applicable in the LAC region

At least three levels of guidelines are available in the LAC region for the management of hypertension: national, regional and international.

These regional and international guidelines concur on several issues such as using nonpharmacological therapy as the first-line treatment and varying the pretreatment observation period according to age and the severity of hypertension. However, these guidelines disagree on other key issues such as the indications for ambulatory blood pressure monitoring or echocardiography and the thresholds for the initiation of antihypertensive therapy and the choice of agents.

The implementation of clinical practice guidelines developed in other regions for decision making about the control and management of hypertension in the LAC region could benefit local decision makers by enabling them to take advantage of existing analyses and transfer or adapt these findings to the local context. However, this precludes the assessment of the generalization and potential transferability to the LAC region, which has not been studied and which begs the following questions: What should be done in the LAC region? Should guidelines for each country and area continue to be formulated? Should international guidelines be adapted (tropicalized)? Should attempts be made to characterize population groups according to their socioeconomic conditions, regardless of where they live? Should diagnoses and treatment algorithms be developed for each condition?

We propose that a solution to this dilemma could be that every set of guidelines has two parts:

Implementation of guidelines in daily practice

The implementation of guidelines in daily practice faces severe challenges. The real utility and success of clinical practice guidelines depend not only on correct elaboration of the best evidence-based medicine available but also, and very importantly, on their implementation to influence decision making by the stakeholders in hypertension: patients, physicians, health authorities and the health industry. In addition, clear and reliable audit processes should be developed to assess their levels of penetration. In particular, the impact of these stakeholders on reducing complications, mortality and morbidity should be part of the process.

There is a paradox in the process of implementing clinical practice guidelines: the communities where they are the most needed are those in which they are the most difficult to implement. The less educated the population, the greater the need for guidelines but the greater the difficulties in implementation.

Although the implementation of evidence-based guidelines would result in a clear improvement in clinical practice, the acceptance of hypertension guidelines and their implementation in clinical practice by physicians continues to be less than optimal.

Many potential barriers may interfere with the application of guidelines in clinical practice. A previous review classified these difficulties into three categories: knowledge, attitude and behavior [Cabana et al. 1999]. Barriers can also be identified at the levels of the clinician, the patient, the characteristics of the guideline itself, and various external barriers.

At the level of the practitioner, several reasons have been used to explain the low adherence to the guidelines. The most frequently reported were the following: discordance between the guidelines produced by different organizations; the gap between the academic writers of guidelines and those whose task it is to implement them; physicians’ unawareness of the recommendations; the physicians’ attitudes and knowledge in addressing clinically relevant issues; formats that are not user-friendly; lack of local involvement; lack of implementation strategy; failure to incorporate patient–clinician values; poor methodological quality; inability to overcome the clinical inertia of previous practice; and the lack of motivation to change [Lebeau et al. 2014]

External barriers that may influence the low penetration of the guidelines in daily practice include time constraints, the lack of resources and the lack of a patient reminder system [Rubinstein et al. 2009].

Attempts to improve the implementation of models of healthcare for hypertension in the LAC region

Currently, there are two projects for the implementation of strategies for managing hypertension in the LAC region in the near future:

This project was reported by CDC in collaboration with the Pan American Health Organization (PAHO):

‘The CDC, Pan American Health Organization (PAHO) and other regional and global partners are collaborating to launch the Global Standardized Hypertension Treatment Project. This project involves the development and implementation of a framework for standardizing the treatment of hypertension using medications. The approach was inspired by successful infectious disease models, such as those used in global tuberculosis and HIV management. Central elements include structured treatment with a core set of medications, treatment protocols with targets, and patient cohort monitoring. The project design aims to be feasible and flexible so that it can be applied worldwide and complement existing hypertension guidelines’ [Centers for Disease Control and Prevention, 2013].

This project was described in a report by Lopez-Jaramillo and Molina:

‘In May 2014, a group of experts of the Latin America Society of Hypertension (LASH) representing 12 countries met in Cartagena de Indias (Colombia) and agreed to implement the ‘20 × 20 LASH target’ with the goal of achieving a 20% increase (relative to the Latin America data of the PURE study) in the awareness, treatment, and control of hypertension by 2020. To reach this goal, LASH has developed and is implementing the Latin American guidelines for Hypertension, Diabetes and Metabolic Syndrome for use by primary care personnel and is developing a virtual Masters Course in the Practical Diagnostic and Management of Hypertension and associated cardiovascular risk factors, specifically designed for general practitioners and nurses in the region. The course has a particularly strong emphasis on how to implement strategies of information, communication, and education to the community’ [Lopez-Jaramillo and Molina, 2015].

Recommendations for new hypertension guidelines in the LAC region

What is appropriate regarding the recommendation of new guidelines for the LAC region? In developing a truly applicable set of guidelines for the LAC region, it seems sensible to first work on developing information in the region. IASH could accomplish this task in the near future.

The following topics are recommended for future research:

New guidelines could be conditioned by the social, economic and cultural levels of the human group to which they are addressed. Stratification should be established according to the socioeconomic groups within countries. In addition, the guidelines must be understood within the context of patient risk rather than by simply considering blood pressure levels.

These requirements must be met to improve the quality, applicability and implementation of new guidelines for the LAC region. Furthermore, they warrant a call to action for the improved control of high blood pressure and other cardiovascular risk factors across the region. The achievement of these ambitious goals will require collaborative efforts by many groups, including policymakers, international organizations, healthcare providers, universities and society in general.