Early blood treatment cuts by half in-hospital death risk in iTTP
US study shows benefit of plasma exchange within 1 day of admission
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Starting plasma exchange — a procedure to replace a portion of a patient’s blood with that of a healthy donor — within one day of hospital admission among adults with immune-mediated thrombotic thrombocytopenic purpura (iTTP) reduces the risk of in-hospital death by half.
That’s according to a large U.S. national study looking into the treatment, in which a patient’s plasma, the portion of blood without cells, is removed and replaced with donated healthy plasma. The strategy is recommended, along with other treatments, under current guidelines when iTTP is suspected.
The researchers found that using the treatment early versus later on lowered the risk of death for patients by slightly more than 5o%.
“These findings reinforce current practice paradigms of early empiric treatment in suspected iTTP and highlight the importance of system-level strategies to minimize delays in plasma exchange initiation,” the researchers wrote, adding that “suspected iTTP should be treated urgently.”
The study, “Clinical predictors of mortality in immune thrombotic thrombocytopenic purpura: A National Inpatient Sample analysis,” was published as a research letter in the British Journal of Haematology.
In iTTP, the immune system mistakenly attacks ADAMTS13, an enzyme that normally helps regulate blood clotting. Such attacks reduce enzyme levels, leading to the formation of blood clots in blood vessels, a condition called thrombotic microangiopathy. This damages red blood cells, lowers levels of platelets — tiny cell fragments that help the blood to clot — and injures organs by reducing blood flow.
Scant data on survival in hospitalized iTTP patients
For patients, when iTTP is suspected, the available treatment guidelines recommend starting plasma exchange at once, alongside corticosteroids and Cablivi (caplacizumab-yhdp), an injectable therapy for acquired TTP, a form of the condition that typically manifests in adulthood.
Still, despite the improved outcomes that have accompanied the adoption of new treatments, there remains limited U.S. data on factors predicting survival after hospitalization in people with iTTP.
To fill this knowledge gap, a team led by researchers at Rutgers New Jersey Medical School examined U.S. hospital records from 2016 through 2022. The researchers used records from the National Inpatient Sample, a large U.S. database.
The team identified 12,095 hospitalizations for both thrombotic microangiopathy and plasma exchange, used as a proxy for iTTP diagnosis. The median patient age was 50, and two-thirds were women. Black patients made up the largest racial group — 43% — of the sample.
Overall, about 9% of patients died during their hospital stay, the data showed. That rate showed no clear upward or downward trend from 2016 to 2022, moving between 6.9% and 10.1% year to year.
According to the researchers, nearly three times fewer patients who received plasma exchange early — within one day of admission — died, compared with those whose treatment was delayed (5.6% vs. 14%), or given more than one day after admission.
Patients who didn’t survive tended to be older, white individuals, and more likely to have Medicare insurance than those who survived. The individuals who died also tended to have higher total hospital charges, the data showed.
Additional health conditions, including chronic kidney disease, chronic lung disease, cirrhosis (liver scarring), chronic heart failure, and cancer, were also more common among the patients who died.
Those who died while in the hospital were more likely to have complications such as sepsis, a severe infection response, and gastrointestinal bleeding. Other complications seen in those who died were acute kidney injury, acute heart failure, cardiac arrest, complications affecting the nervous system, need for a breathing machine, and use of medications to support blood pressure.
Lower risk of in-hospital death seen even amid complications
In a statistical analysis that adjusted for demographic and baseline, or initial, clinical factors, early plasma exchange remained strongly linked to a lower chance of dying in the hospital. Specifically, the analysis found the risk of death for patients treated within one day of admission was 51% less than for individuals treated later.
Older age, chronic lung disease, chronic heart failure, COVID-19 infection, and cancer (solid tumors or blood cancers) were each linked to a higher risk of death, the data showed. Black patients had a lower risk of death compared with white patients.
When the researchers also accounted for complications that developed during the hospital stay, early plasma exchange still showed a protective association, with a 34% reduced risk of dying.
Sepsis, acute kidney injury, acute heart failure, nervous system complications, and gastrointestinal bleeding were each independently linked to higher mortality, while heart attack was not.
When the researchers treated timing as a continuous measure rather than an early/delayed category, each additional day before starting plasma exchange was associated with a 6% increase in the odds of death, the data showed.
In this large national [patient group], early [plasma exchange] was one of the strongest modifiable predictors of survival among [patients].
Early plasma exchange was still linked to a lower death rate when patients who were pregnant, had COVID-19, cancer, or a transplant history were excluded from the analysis. A simpler analysis that adjusted only for age, sex, and race or ethnicity showed the same pattern.
The 8.8% death rate in this study is similar to previous national estimates, which ranged from 7.5% to 11.1% over the prior decade, suggesting death rates from iTTP have remained fairly stable despite newer treatments, the team noted. Cablivi’s effect could not be assessed because medication use is not reliably recorded in this database.
Among the study’s limitations, cases were identified using diagnosis and procedure codes rather than direct laboratory confirmation and ADAMTS13 activity levels, which are used to confirm iTTP. And as the database counts hospital stays rather than individuals, those with more than one iTTP episode may have been counted more than once, the team noted.
Still, the researchers say the data show that “early initiation of [plasma exchange] was independently associated with lower in-hospital mortality among TTP hospitalizations.”
“In this large national [patient group], early [plasma exchange] was one of the strongest modifiable predictors of survival among [patients],” the team concluded.
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