This study highlights the regional characteristics in the epidemiology of group 1 PH.
The recognition of these differences should be considered when developing clinical guidelines and extrapolating diagnostic and treatment algorithms. Equitable access to health care and therapies are also issues that need to be addressed in Latin America. Information coming from a large prospective registry representing the different populations in Latin America is of critical importance to increase disease awareness in the region and improve diagnosis and management. Pulmonary arterial hypertension PAH , a clinical classification of group 1 pulmonary hypertension PH , is a rare, progressive disease with poor prognosis.
It has a worldwide estimated prevalence ranging from 10 to 16 cases per million inhabitants per year and an incidence between 2. In the last two decades, knowledge of the basic pathobiology of PAH, its natural history, prognostic indicators, and therapeutic options have improved. National registries have provided a better understanding of the epidemiology and clinical evolution of the disease [ 3 ] as well as valuable information on disease characteristics, demographics and outcomes of patients with PAH [ 4 ], allowing the development of risk stratification tools [ 5 ].
Moreover, no Latin American studies were included in these reviews. This is particularly important as researchers have described that there are potential geographical and regional differences which are vital to consider in the design of clinical trials as well as PAH treatment [ 2 , 6 , 7 ]. Studies were required to report on at least one of the following topics: clinical characteristics etiology, time from onset of symptoms to diagnosis, hemodynamic parameters and severity of the disease based on the World Health Organization — WHO — classification ; demographic characteristics age and gender ; treatment pattern or survival rates in a cohort of PAH patients.
Additionally, studies that focused on patients with a specific etiology associated with group 1 PH such as schistosomiasis, HIV, lupus or coronary heart disease were also excluded. Due to the paucity of data, the decision was made to include conference abstracts if they have any publication describing the study design to assure the correct understanding of the data collection, patient inclusion, study results and methodology.
Two reviewers independently extracted data using a standardized data extraction form. A total of 22 publications including articles and conference abstracts were retrieved by the literature search. Fourteen conference abstracts were screened. From these, twelve were excluded. The Mexican registry [ 9 ], two abstracts that reported data from the Colombian registry [ 10 , 11 ] and a study from Puerto Rico [ 12 ] were excluded as they did not report data separately for group 1 PH patients.
Additionally, one registry from Uruguay [ 20 ] was excluded as they did not provide another publication detailing the study design. The data from the abstracts was complemented with methodological information from the study protocols [ 23 , 24 ]. Eight full text articles were found of which four were excluded from the analysis. One study conducted in Brazil [ 25 ] was excluded because unlike the other studies, PH diagnosis was made based only on echocardiography results and did not consider hemodynamic parameters.
The other study from Chile [ 26 ] was excluded as the study included group 1 and 4 PH patients but did not report data separately for group 1 PH. Four articles were included in the final analysis: two Chilean [ 27 , 28 ] one Argentinean [ 29 ] and one Brazilian [ 7 ]. In total, six publications two conference abstracts and four full articles were qualified for inclusion according to the eligibility criteria see Fig.
The number of patients with group 1 PH varied from 17 in Chile [ 28 ] to in Brazil [ 7 ]. All the studies included just adult patients, except the Argentinean by Talavera et al.
Pulmonary Hypertension–Back to the Future | Revista Española de Cardiología (English Edition)
As can be seen in Fig. Only one of the Argentinean studies [ 29 ] and one of the Chilean studies [ 27 ] reported the time from onset of symptoms to diagnosis 1. Despite the differences, these values are considered high and demonstrate that most of the patients were in an advanced stage of the disease.
The hemodynamic parameters exhibited the same pattern in all studies. The Brazilian registry [ 7 ] described survival only for incident patients and the Argentine study [ 29 ] showed survival for incident and prevalent patients. Comparing the Brazilian [ 7 ] and Argentinean [ 29 ] registries in the first year, the survival was similar Most of the studies described the treatment received by patients [ 7 , 16 , 28 , 29 ]. It is important to note that the Brazilian registry only included incident patients [ 7 ] and hence only first-line treatment.
Sildenafil was considered as first line treatment in Argentina and Brazil [ 7 ]. This is despite the fact that in Chile the use of inhaled Iloprost was approved in , when the study was finished and Ambrisentan was first approved in , several years after the recruitment period of this study.
While registries are an instrumental source of information regarding the epidemiology and outcomes, they can be influenced by external factors related to local circumstances such as access to health care, disease awareness and living conditions [ 5 , 31 ].
While there was variation in the average age among the Latin American countries, most patients diagnosed were young and of working age. As previously mentioned, the Argentinean study by Talavera et al. This is in contrast with results from developed countries where patients were older at diagnosis. Hoeper et al. However, other factors may play a role such as: referral patterns, PAH awareness, increase patient access to information and widespread use of noninvasive screening tools [ 6 ].
As noted by McGoon et al.
Similar to the results of international registries, the prevalence of PAH in female patients was higher [ 2 , 6 ]. The studies reviewed described differences in the prevalence of IPAH. According to WHO, schistosomiasis affects more than million people worldwide [ 7 ].
Estimates indicate that 8 to 12 million people are infected by schistosomiasis in Brazil [ 31 ], suggesting that schistosomiasis could be one of the main causes of PAH in the country. A recent review [ 35 ] emphasized the remarkable differences that might exist in specific areas of the world, as schistosomiasis in Brazil, or HIV in Africa, that should not be neglected when developing health policies for the appropriate diagnosis and management of PAH.
Functional class is a powerful predictor of outcomes in patients with PAH [ 36 ]. This is still the case when studies consider only incident or both prevalent and incident cases. However, even lower than in US and Europe, the percentage of patients in advanced functional class is still very high in Latin America, evidencing that patients are still diagnosed at late stages suggesting a lack of disease awareness and limited access to health care. However, it is important to consider that the mean age of patients was lower in Latin America, which could contribute to a better 6MWD.
Alves et al.
CritCases 7 Pulmonary Hypertension – A Fine Balance
Three studies reported survival rates. The Argentine registry had the highest 3-year survival rate [ 29 ].
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The Brazilian study with only incident patients showed a high survival rate in the first year but in the second and third years the survival rate decreased [ 7 ]. In general, Latin American patients had similar survival rates as patients in developed countries. The French [ 32 ] and REVEAL [ 33 ] studies exhibited a survival rate lower than the Argentinean [ 29 ] and Brazilian studies [ 7 ], despite the lower availability of targeted therapies in Latin America.
Patients with typical PAH were younger, without any remarkable difference in the hemodynamics profile. Although with similar overall survival, the response to treatment was higher in the subgroup with typical PAH. The study suggests that the presence of comorbidities might significantly influence the spectrum of PAH disease by adding different pathophysiological mechanisms to the more isolated vascular disease seen in the typical PAH. The lower mean age evidenced in Latin American patients suggests a lower prevalence of comorbidities which could contribute to a better survival rate in the region.
Nevertheless, the lack of appropriate description of the comorbidities in the selected studies prevented a proper evaluation of the role of typical and atypical PAH prevalences in the overall survival. Despite the fact that data on PAH treatment in Latin America is limited, oral drugs appear to be the main form of first line therapy with Sildenafil being the most commonly used drug for PAH treatment within the region. The lack of data on combination therapy may be due to the fact that it is not approved in most Latin American countries.
It is also important to point out that some treatments that were reported in the studies have not been approved for PAH use in the countries where data was collected. This highlights the fact that entering a clinical trial may be one way of providing PAH patients an opportunity to receive specific treatment [ 31 ].
Timely and improved access to medicines may still be limited in the region. Efforts should be made to improve early diagnosis and the availability of new treatments which in turn may increase survival rates of PAH patients in Latin America. Our study has limitations that need to be acknowledged. There is a clear paucity of available data regarding PAH in the region. Most of the PAH data in Latin America is available only in conference abstracts, making it difficult to evaluate the profile of PAH patients among the region.
Research from non-English speaking countries is underrepresented in high-impact medical journals and indexation problems for journals in Spanish and Portuguese hinder the screening of studies. While national registries are currently being implemented in different Latin American countries, accurate epidemiologic information on PAH is still limited.
This registry has been designed to collect medical history, diagnostic methods and treatment of patients suffering from pulmonary hypertension PH under optimal medical care in an effort to better fill the existing gap on the knowledge about the broader distribution of PAH in the region. PAH is a specific type of pulmonary hypertension that is caused by the development of scar tissue in the tiny blood vessels of the lung.