Prevalence, comorbidities among patients in Brazil detailed in study

Aplastic anemia, other bone marrow disease seen in about half of PHN patients

Marisa Wexler MS avatar

by Marisa Wexler MS |

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A rare disease, paroxysmal nocturnal hemoglobinuria (PNH) affects roughly 1 in of every 237,000 people in Brazil, a study estimates.

Its findings shed light on common comorbidities, or co-occurring health conditions like aplastic anemia, affecting PNH patients in that country, as well as the causes of death in those hospitalized.

“This may be the first epidemiological study in order to assess characteristics of PNH patients in Brazil based on data from the public health system,” the researchers wrote.

Characteristics of paroxysmal nocturnal hemoglobinuria patients in Brazil: A retrospective administrative claims database analysis of PNH patients in Brazilian public healthcare system,” was published in PLOS One.

Alexion, a subsidiary of AstraZeneca that markets the approved PNH treatments Soliris (eculizumab) and Ultomiris (ravulizumab), funded the work.

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PNH affects large number of whites in Brazil, relative to country’s population

PNH is caused by mutations that develop in stem cells that give rise to new blood cells, resulting in the hemolysis (blood cell destruction) that leads to disease symptoms.

A team of scientists in Brazil conducted a review of an insurance databaseto assess the experience of people with PNH there.

“As PNH is a rare condition, retrospective studies using large databases can provide a unique perspective on patient profiles,” the scientists wrote.

“Therefore, this study aims to describe the main clinical and epidemiological characteristics in this population (age, sex, geographic region, and associated comorbidities), as well as their health care (including procedures and visits to health professionals), and estimate the hemolysis-related in-hospital mortality among PNH patients,” they noted.

Researchers used DATASUS, a large database that collects insurance claims information for people who receive healthcare through Brazil’s public system. The database covers some 160 million people, roughly 75% of Brazil’s population.

They identified 675 individuals with insurance claims related to PNH between 2008 and 2018. Slightly more than half were female, the average age was just over 44 years old, most patients lived in southeastern parts of Brazil.

According to the team, the Southeast region is “the most populous and the one with the highest concentration of physicians in the country. These regional characteristics may explain the higher concentration of PNH patients observed … as access to medical care can facilitate diagnosis and referral to specialized treatment.”

Based on the number of patients identified and the database’s total population, the researchers estimated that PNH affects roughly 1 out of every 237,000 people in Brazil.

“This estimate may be relevant, given the lack of data on the prevalence of this disease in South America,” they wrote.

Nearly two-thirds of the PNH patients were white (63.2%), which the researchers noted is disproportionate to the overall Brazilian population that is white (42.3%).

Aplastic anemia among more common co-occurring conditions with PNH

Regarding PNH-related comorbidities, approximately 15.8% of the patients had a recorded insurance claim related to myelodysplastic syndrome (poorly formed or working blood cells), while about half had aplastic anemia or other bone marrow disorders. People with PNH are known to be at increased risk for these conditions.

Clotting-related health problems (thrombosis), which can be a major cause of mortality in PNH, were documented in 4.3% of the patients. Just under 1% had portal vein thrombosis, where a clot blocks blood flow in large blood vessels in the liver.

Analyses of healthcare use showed that visits to specialists, especially hematologists (blood specialists), increased markedly after patients received an initial diagnosis of PNH.

“Visits to other health care providers usually associated with laboratory and imaging tests … were also more common after PNH diagnosis, potentially indicating an increase in the use of such health resources,” the researchers wrote.

A total of 416 hospitalizations were recorded for 263 of the PNH patients analyzed, and 12 deaths in hospitalized patients were recorded in the study, translating to an in-hospital mortality rate of about 4.5%.

In two such cases, PNH was listed in insurance claims as a direct cause of death. In three other cases, the listed cause of death was a potential complication related to PNH, including hemolytic anemia, aplastic anemia, and acute respiratory failure. In the remaining seven cases, there was no obvious connection between PNH and the cause of death.

The researchers highlighted that their study is limited by its reliance on insurance claims data, which is designed to help facilitate care coverage and not to analyze clinical outcomes.

“Despite these limitations, to our knowledge this is the first nationwide study addressing characteristics of PNH patients in Brazil, covering both demographics, comorbidities, hospitalization, and mortality,” the team concluded. “Further research combining other data sources such as medical charts, laboratory tests and patient interviews could elucidate other aspects of the disease burden and clinical course of PNH in Brazil.”