PAH rates, deaths show diverging trajectories in rich and poor nations
Study tracks global shift in prevalence, mortality over 3 decades
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Over the past three decades, rates of pulmonary arterial hypertension (PAH) have increased in wealthy parts of the world, including the U.S. and Europe — but though the rare disease has become more common in richer nations, the rates of death due to PAH have nonetheless decreased over time in these countries.
Meanwhile, in less advantaged regions around the globe, such as sub-Saharan Africa and Latin America, the opposite trend has occurred: Rates of PAH have gone down, but death rates due to the disease have increased.
Those are the findings of a new study, titled “Global Burden of Pulmonary Arterial Hypertension in Older Adults and Its Causal Association With Body Mass Index,” that particularly focused on people ages 60 and older with PAH. The work was published in the journal Pulmonary Circulation by a research team in China.
“Marked geographic and [socio-demographic]-related disparities were observed,” the researchers wrote, noting, however, that “substantial knowledge gaps remain regarding the global distribution of PAH in older adults, its long-term … trends, and the socio-economic drivers underlying these patterns, as well as regarding heart failure attributable to PAH.”
The team noted that body mass index, a ratio of height and weight used as a proxy for body fat, “may represent a potentially modifiable risk factor for PAH.” However, per the team, both the condition’s prevalence and mortality were also tied to diagnosis and treatment.
Based on their findings, the researchers called for increased efforts to improve access to care for people with PAH worldwide.
A chronic disorder, PAH is characterized by elevated pressure in the vessels that carry blood from the heart through the lungs. This ultimately strains the heart muscle, leading to symptoms such as severe shortness of breath. In its severe stages, it can result in heart failure.
According to the researchers, “risk factors for PAH among older adults remain insufficiently characterized.”
Researchers tracked global PAH stats from 1990 until 2021
To learn more, a team from the School of Basic Medical Sciences at Ningxia Medical University combed through global data from 1990 through 2021. Their goal was to track how PAH trends have evolved over time, specifically focusing on individuals 60 years and older.
The researchers found that, worldwide, the age-adjusted incidence of PAH — that is, the number of people newly diagnosed with the disease — has increased over the past three decades. At the same time, age-adjusted rates of death due to PAH have decreased worldwide.
However, these trends diverged in different regions of the world, the researchers found. Very generally, data suggested that, in wealthier nations, the incidence of PAH has increased, while rates of PAH-related death have gone down. These trends, per the scientists, are likely attributable to the fact that patients in wealthy nations usually have better access to care. In less wealthy nations, patients typically face more difficulties getting diagnosed and treated appropriately, the team suggested.
“In high-income settings, wider availability of targeted therapies and multidisciplinary care has reduced mortality, yet intensifying population aging continues to push incidence and prevalence [how common a disease is] upward,” the researchers wrote. At the same time, the team noted, low-income countries “face the dual constraints of limited diagnostic capacity and scarce resources.”
Death rates higher in poorer countries despite fewer cases
The scientists stressed, however, that economic differences did not fully explain differences in PAH-related deaths from country to country. For instance, analyses indicated that PAH death rates remain somewhat higher in the U.S. and Sweden, compared with what would be expected given these countries’ economic and social development levels.
This is “possibly related to gaps in early diagnosis or uneven care pathways,” the researchers wrote, adding that “these findings indicate that imbalances in health-system efficiency — rather than economic status alone — are a key bottleneck in global PAH control among older adults.”
Public-health strategies should prioritize improved PAH surveillance, diagnostic capacity, equitable access to targeted therapies, [and] geriatric cardiopulmonary care.
Overall, the results underscore the need for public health initiatives to improve outcomes for people with PAH, the researchers said. The team noted that, based on their data, the worldwide incidence of PAH is expected to keep increasing over the next decades.
“Public-health strategies should prioritize improved PAH surveillance, diagnostic capacity, equitable access to targeted therapies, geriatric cardiopulmonary care, and metabolic-risk prevention,” the researchers wrote.
In addition to their epidemiological analyses, the researchers conducted genetic reviews using a technique called Mendelian randomization (MR). This essentially aims to use genetic data to look for associations between risk factors and disease outcomes. In this case, the researchers used MR to look for associations between PAH and BMI.
Results from the MR analyses indicated that people who are genetically predisposed to putting on more weight are also more likely to develop PAH. These findings add to a large body of evidence linking obesity with PAH risk, the researchers said, noting that public health initiatives to reduce obesity may also help decrease the societal burden of PAH.
“The persistent rise of PAH in adults aged … 60 years [or older] has become a major challenge for global health equity,” the researchers wrote.
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