Dementia in Latin America

The goal of this work

In this Perspective, we discuss the clinical and research priorities necessary to enable harmonization of strategies to tackle the dementia challenge in LAC. Regarding clinical priorities, we discuss the current diagnostic procedures (table 1), the need for improving physician training, and factors affecting timely diagnosis and care. We also consider specific issues regarding mental health facilities and policies. Regarding research priorities, we highlight the lack of epidemiologic data and the need for standardized diagnostic procedures. We also discuss the use of biomarkers and the context of clinical trials in LAC. Finally, we propose avenues for collaborations including dissemination forums, research with unique populations, and opportunities for a regional network for translational research. A consensus is needed to enter the global dementia scenario with an appealing proposal that focuses on the harmonization of actions across LAC in a way that captures global dementia strategies.

The dementia challenge for LAC was recently highlighted in the World Congress of Neurology meeting held in Santiago, Chile.² A group of experts from various LAC came together to discuss concerns regarding barriers and challenges in clinical research practice (appendix e-1, S2, links.lww.com/WNL/A97). Four topics were addressed and are discussed here: (1) timely diagnosis, (2) therapeutic approaches, (3) social and health support after the diagnosis, and (4) potential avenues for collaboration toward unmet needs. It was acknowledged by consensus that such topics could trigger immediate actions (table 2).

Timely diagnosis

Recent dementia recommendations stress the importance of systematic and exhaustive clinical and cognitive investigations, as well as biomarker approaches, to support both the timely diagnosis of Alzheimer disease (AD)⁶ and prevention initiatives.^7,8 Whether such recommendations can be harmonized across the developed and developing world is unclear at present. Moreover, the potential benefit of timely diagnosis and the clinical utility of biomarkers has been questioned both at the societal and individual level.^9,10 Although the use of biomarkers as diagnostic criteria offers value in research settings, concerns about the premature use of biomarkers in clinical settings have been raised. Even if biomarkers are proven to be accurate for diagnosis, the associated patient benefit should be considered, particularly in light of the cost of proposed biomarkers and the necessary access to high-level equipment that is currently unavailable in most LAC.¹¹ The utility of biomarkers is further questionable in low-income countries (LIC), where the priority should be timely diagnosis using affordable neuropsychological and clinical assessments, and appropriate patient care. Thus, the potential utility of biomarkers may be predominantly in high-income countries (HIC) and to a lesser degree in upper-middle-income countries (UMIC). Thus, the use of biomarkers may represent a step toward better future assessment predominantly in HIC,¹² while care and clinical assessment should be a priority in LIC and UMIC (see below). There is a stringent limit to the budget available for research in LIC and UMIC and the use of biomarkers would likely imply a tradeoff between quality of measurement and other desirable features of research such as geographic, socioeconomic, and racial diversity of sample participation as well as sample size, response rates, and cost, to mention a few.

Challenges for LAC relevant to this call include the current epidemiologic landscape, training of health care practitioners, procedures followed to make a diagnosis, and factors affecting timely diagnosis.

Current epidemiologic landscape

From 2015 to 2050, the number of people with dementia in LAC is predicted to increase 4-fold.^3,13,–,15 By 2020, 89.28 million people with dementia will live in LMIC (in LAC: Bolivia, el Salvador, Guatemala, Honduras, Nicaragua, Paraguay), relative to the 42.18 million living in HIC. In addition, UMIC, such as Argentina, Brazil, Chile, Costa Rica, Cuba, Colombia, Dominican Republic, Ecuador, Mexico, Peru, Uruguay, and Venezuela, will experience the greatest dementia impact.¹⁶ As is the case globally, the expected increase in dementia in LAC is partly due to the aging population.^17,18 A combination of unsuitable diagnostic procedures and low awareness has prevented accurate estimates of dementia prevalence in LAC.¹⁹ The WHO reported a dementia prevalence of 5.5%–7% with a standardized prevalence of 8.5%, although several LAC are underrepresented in these statistics,¹⁶ and dementia prevalence may be underestimated.²⁰ Most reports rely on a limited number of studies, which provide only a partial picture of the problem in LAC.⁴ Thus, more rigorous epidemiologic studies are required²¹ (table 3).

The Alzheimer's Disease International (ADI) report¹⁴ included figures from Cuba, Dominican Republic, Jamaica, Peru, Venezuela, Mexico, Chile, and Brazil (14 publications). Ethnic minorities in the United States reported prevalence of dementia in Caribbean Hispanic Americans (12.2%) higher than in Mexican Americans, Japanese Americans, and non-Latino white populations.²² In fact, ADI reported the highest global prevalence of dementia in LAC (8.4%) after North Africa/Middle East (8.7%) in people >60 years.¹⁴ Variability of dementia prevalence rates across LAC, however, is large (ranging from 2% in Brazil²³ to 13.7% in Venezuela,²⁴ but this has also been reported in some European countries²⁵). It has been suggested that such variability may result from differences in methodologic procedures across studies (e.g., diagnostic criteria). Nevertheless, the crude estimated prevalence of dementia in LAC in people >60 years (6.54%) exceeds international prevalence (5.2%),¹⁶ demonstrating the challenge ahead for LAC (table 3).

In countries such as Cuba, Dominican Republic, Mexico, and Peru, dementia represents the largest contribution to disability.²⁶ The Global Burden of Disease Study (2010) reported that dementia is also one of the key determinants of disability and mortality in older people.⁵ In some LAC, dementia leads to an increase in time disabled by over 200%, and the number of deaths due to dementia has increased by 526%. Moreover, higher rates of deaths among people with dementia in hospital settings are observed in some LAC²⁷: Cuba 41.4%; Dominican Republic 29.1%; Peru (urban) 31.0%; Peru (rural) 83.3%; Mexico 31.3%. Notably, hospitalization is one of the main health care cost factors in dementia.

Health care practitioners responsible for the diagnosis of dementia

The diagnosis of dementia in LAC is usually made by a neurologist, psychiatrist, or gerontologist, or on rare occasions, by a general practitioner.²⁸

Procedures followed to make a diagnosis

Most LAC follow a basic 3-step clinical algorithm that comprises screening, diagnosis, and classification (i.e., dementia subtypes). Diagnosis is primarily based on clinical information and detailed cognitive assessments are primarily available in private institutions only (table 1). Availability of imaging and biomarkers is restricted to a few centers. For instance, in Argentina, a few institutions have incorporated AD biomarkers as part of international protocols (e.g., the Alzheimer’s Disease Neuroimaging Initiative). Genetic screening is rare with some exceptions (i.e., Colombia and Argentina, not at a national level, but focused on a few centers). The Neuroscience Group of Antioquia has implemented a genetic interview to investigate family inheritance of neurologic diseases. This approach has been key to revealing an unprecedented geographic clustering of neurodegenerative genetic diseases in that country.

Basic recommendations and guidelines for dementia diagnosis are available in a subset of LAC only (e.g., Chile, Argentina, Mexico, and Brazil).^16,27 In Chile, the Ministry of Health launched guidelines for primary care and a Chilean Society has launched guidelines for specialists. In Argentina, the first Clinical Practice Guidelines have been reported, while the Brazilian Academy of Neurology has made recommendations on diagnostic criteria, screening, neuropsychological evaluation, blood tests, and neuroimaging. However, a much broader health approach as recently launched in HIC¹⁶ is required. Thus, although there is local awareness in some countries regarding the importance of harmonizing diagnostic procedures, this awareness has not reached a regional level (i.e., LAC). Moreover, multiple factors such as resources, culture, language, and stigmas affect the accurate diagnosis (table 4).

Therapeutic approaches

Experience running international or local clinical trials in LAC is mixed. A small amount of drug trials reported worldwide have included LAC, with differences among countries. This region offers an appealing environment for dementia research, although more regional integration is required (table 4). The regional experience lacks systematic organization and regional registries. In some cases, strong bias and negative stereotypes about medication have been observed.

Local regulations

An important factor limiting participation of LAC in international clinical trials is the position of relevant ethics committees, which until recently have had strong reservations about clinical trials in developing countries, even when they are part of international initiatives. However, there are encouraging examples in the region, including a landmark prevention trial in familial AD in Columbia.^7,29 Some LAC have government regulations that pose challenges to clinical trials. For instance, in Chile, a new law on patients' rights and duties imposes several restrictions. Article 23 of the law 20584 prohibits the participation of vulnerable people in scientific research studies who are unable to provide consent. This has caused concerns among ethics committees, which have had to reject applications based on such legislation, affecting researchers as well as people with dementia. Also, most research is supported by industry, with academic trials representing a small proportion of research and involving small sample sizes (although this does not seem to be specific to LAC). The implications of this pattern for the direction of research as well as the validity and availability of results merits attention in future works. Finally, no regional guidelines for multicountry clinical trials exist. Thus, some local regulations may need to be revised to reflect global dementia strategies.

Currently available treatments

Unlike many HIC (e.g., United Kingdom, France, Norway, United States, and South Korea) where governments have developed specific dementia plans or strategies, most LAC have minimal mental health facilities with no specific policies or budgets for mental health.¹⁵ Currently available treatments, research opportunities, and clinical assessment of dementia appears to depend on a country's political stability and economic capacity^16,30,–,32 (appendix e-1, S6, links.lww.com/WNL/A97).

In Chile, as in many other LAC, care is mostly delivered by family relatives, with most of the cost of dementia accounted for by informal care.¹⁶ Availability of pharmaceuticals for dementia across LAC is variable, with the exception of Mexico, where the cost of dementia medications is much lower than in other LMIC.²⁷ In Colombia and Peru, only private health insurance companies provide acetylcholinesterase inhibitors (AI) or glutamate modulators. In Chile, the public health system delivers pharmaceutical treatment for neuropsychiatric symptoms of dementia, but does not cover specific treatments for dementia subtypes. The Brazilian government supports treatment with AI for AD; however, respite facilities or nursing home access are not supported. In Argentina, AI, Souvenaid, and Cerebolysin are supported by the public health system. Moreover, patients with dementia have access to a national certificate of disability, which allows them access to full medical coverage. In general, memory enhancers are difficult to obtain. Moreover, nonpharmacologic treatments, as well as social and health support postdiagnosis, pose similar challenges in LAC (tables 5 and 6).

Nonpharmacologic approaches may offer an attractive alternative for LAC. At the Alzheimer's Association International Conference 2016, evidence on cognitive intervention programs using information technology was presented. Such approaches have shown relevant improvements in cognitive functions, transfer across cognitive domains, and enhanced functioning in randomized controlled trials. Interestingly, these effects appear to persist to some extent for at least 5 years.³³ More recently, the Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER) study has combined comprehensive intervention with technology to enhance cognitive functions.³⁴ The use of technology has become common practice among older people from LAC. Some researchers have started to investigate whether this social trend could offer new opportunities to assess functioning in those at risk of dementia.³⁵ Nevertheless, we acknowledge that though promising, this area is in its infancy and more work will be needed before it can be introduced into clinical practice.

Potential avenues for collaboration

Even at a global level, comprehensive dementia health care cannot be afforded by existing care models.²⁷ The potential of LAC to tackle important priorities in dementia research is unanimously acknowledged by this expert panel.

Promoting collaboration forums and large-scale computational capacity

One option for LAC is to establish an agenda to organize meetings in different countries, which could create opportunities for researchers to discuss local work and increase scientific debate and interactions (appendix e-1, S4, links.lww.com/WNL/A97). Secondly, the development of large-scale computational capacity (e.g., Linux clusters) would offer a platform for intensive dementia research, screening programs, and big data analysis (appendix e-1, S4).

Capitalizing on unique populations

LAC offer access to unique populations (genetic clusters, low literacy, multilingual, multiethnic).³⁶ This region hosts the world's largest populations of familial AD (Colombia), Huntington disease (Venezuela), and ataxia (Cuba), alongside multiple novel and rare functional genomic variants of other diseases. For instance, the Caribbean has a high late-onset dementia incidence, and genetic studies have shown large effect sizes.³⁷ These unique genetic presentations can be exploited at a regional level. Moreover, the socioeconomic status of several communities provides a natural scenario to study the role of vulnerability, resilience, and gene–environment interactions, such as in the blue zones. Multilingualism is another important factor that can be studied. Many LAC are suitable for studying bilingualism and its influence on cognitive reserve in situ. In LAC, it is possible to find people who are illiterate, but still functioning at a relatively normal level within their community. In Mexico, Peru, Cuba, and Dominican Republic, education and literacy seems to protect against dementia onset.²⁰ Studying these populations may help to disentangle the effects of education and other social factors. Finally, the development of robust cognitive neuroscience methods to tackle dementia research are now emerging in the region.^38,–,51 However, the need for more research at a global level is necessary²⁷ and LAC should be integrated into this pathway.

The unique conditions found in LAC could inform causal inference by etiologic triangulation.⁵² This triangulation from different approaches and measures can unveil key sources of potential bias. Combining different regional approaches (within LAC and among LAC and other regions) with studies at different levels (genetic, cognitive, neuronal, epidemiologic), which are available to researchers globally at a modest cost, will represent a novel advance in the field of dementia.

Toward a regional network for translation research

Several LAC are currently working with animal models. Examples include the Neuroscience Group of Antioquia, Colombia; the Federal University of Rio de Janeiro, Brazil; the Max Planck Institute and the Institute of Cognitive and Translational Neuroscience in Argentina; the Geroscience Center for Brain Health and Metabolism; and the Fraunhofer Institute from Chile. Advances are being made by studying species such as the Octodon degus, an endemic rodent from Chile that spontaneously develops an analogue of dementia.⁵³ The use of low-cost accessible technologies such as inexpensive cognitive screening tools that are culturally unbiased⁵⁴ as well as additional measures such as high-density, portable, and even basic EEG^40,45,55,56 may provide affordable improved assessment solutions in the short term. Standardization of collection and measurement is necessary to take advantage of clinical developments, imaging, biomarkers, and clinical trials.¹² It is time to do this at the LAC network level.