Patients hospitalized with COVID-19 who received convalescent plasma demonstrated improved survival and were more likely than matched control patients to remain the same or have improvements in their supplemental oxygen requirements, according to a study published in medRxiv. The study details the preliminary outcomes of 39 patients hospitalized at The Mount Sinai Hospital in New York, who were among the very first in the nation to receive convalescent plasma transfusions, compared against a cohort of retrospectively matched controls.
“New York City was among the earliest and hardest hit by the COVID-19 pandemic in the United States, so during the study’s 16-day enrollment period in late March, our Health System had a large, diverse pool of COVID-19 patients from which to draw control patients, allowing us to use an aggressive matching algorithm,” says the co-senior author of the paper. “We are encouraged that our initial assessment offers evidence in support of convalescent plasma as an effective intervention, while remaining mindful that additional studies are needed to confirm these findings and draw more definitive conclusions in different populations.”
For this study, plasma recipients and control patients were 100 percent matched on their supplemental oxygen requirement on day zero, in addition to other baseline demographic factors and comorbidities. Of them, 69.2 percent were receiving high-flow oxygen and 10.3 percent were receiving invasive mechanical ventilation. By day 14, clinical condition had worsened in 18 percent of the plasma patients and 24.3 percent of the control patients. On days one and seven, the plasma group also showed a reduction in the proportion of patients with worsened oxygenation status, but that difference was not statistically significant. As of May 1, 12.8 percent of plasma recipients and 24.4 percent of the 1:4 matched control patients had died, with 71.8 percent and 66.7 percent, respectively, being discharged alive.
Patients were identified as eligible for COVID-19 convalescent plasma transfusion under the criteria established by the U.S. Food and Drug Administration (FDA) single patient emergency investigational new drug process. Plasma recipients were transfused with convalescent plasma from donors with a SARS-CoV-2 anti-spike antibody titer (level) of greater than or equal to 1:320 dilution and all were transfused with two units of convalescent plasma matching the recipient’s blood type.
Importantly, the cohort of matched control patients were retrospectively identified within the hospital’s electronic record database, using an aggressive matching algorithm designed by Mount Sinai biostatisticians that matched the plasma recipients to controls for three levels of patient information: 1) baseline demographics and comorbidities, including age; gender; smoking status; presence of obesity, diabetes, COPD or sleep apnea; and d-dimer and c-reactive protein at admission; 2) day of transfusion data, including supplemental oxygen requirement, length of hospital stay, minimal oxygen saturation, heart rate, respiratory rate, and systolic and diastolic BP; and 3) time series data up to the day of transfusion, including the use of hydroxychloroquine or azithromycin, intubation status, and, if intubated, duration of intubation.
For controls patients, the day of transfusion was defined by the length of stay on which their respective recipient received their transfusion. To confirm the independent effect of convalescent plasma transfusion or improvement in oxygenation and survival, the team conducted a propensity score-matched analysis using The Mount Sinai Hospital’s COVID-19 confirmed patient pool from the same calendar period (March 24 to April 8, 2020). Among the predictors, exact matching was enforced on the administration of hydroxychloroquine and azithromycin, intubation status and duration, length of hospital stay, and oxygen requirement on the day of transfusion.
The COVID-19 pandemic poses an unprecedented challenge, as physicians and scientists struggle in real time to identify effective interventions against SARS-CoV-2 and its complications. The conclusions drawn from these data are not as robust as a prospective, randomized, placebo-controlled study, however this study has the unique strength of propensity score matching, which other case series have lacked.
“The efficacy of passive antibody transfer relies heavily on the quality of the donor convalescent plasma,” says the other co-senior author of the paper. “Mount Sinai rapidly developed and clinically deployed an enzyme-linked immunosorbent antibody test (ELISA) to titrate SARS-CoV-2-specific antibodies in serum, enabling our center the unique ability to refer for blood collection only those convalescent donors with the highest plasma antibody levels. We are profoundly grateful for the generosity of thousands of anonymous residents of the tri-state area who recovered from COVID-19 and then volunteered to donate convalescent plasma for the benefit of others.”
Convalescent Plasma Is A Potentially Effective Treatment Option for Patients Hospitalized With COVID 19
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