In a rare look at the effects of blood transfusions on long-term mortality in the general population, researchers in China have found that mortality from any cause sharply increased among those who had received transfusions, according to study findings published in Clinics.
The findings, stemming from an analysis covering more than 48,000 people in the National Health and Nutrition Examination Survey (NHANES) in the U.S., suggest that blood transfusions could pose a mortality risk over the long term that has not previously been recognized.
“Blood transfusion significantly impacts long-term all-cause mortality and cardiovascular mortality rates in the general U.S. population, potentially being an under-recognized risk factor for death,” said the researchers, led by Jie Shi, PhD, a researcher at the Second Hospital of Lanzhou University in China. “Thus, the effective management of blood transfusion in the general population may be beneficial.”
The study drew on data collected every two years in the NHANES survey, from 1999 to 2018, in which participants were asked whether they had ever had a blood transfusion. The participants’ responses were matched with records from the National Death Index. They were tracked until they died or until 2019, the last year data were available.
Out of 48,004 participants, 6,192 said they’d received blood transfusions. Those who did were mostly older, female, non-Hispanic white, had a body mass index of 30 or higher, and led a non-sedentary lifestyle, researchers found. They were also more likely to have received a transfusion in 1992 or later. They were less educated and more likely to have atherosclerotic cardiovascular disease (ASCVD), cancer, hypertension, diabetes, hyperlipidemia, or anemia, and used more coagulation-modulating drugs.
The prevalence of ASCVD, cancer, hypertension, diabetes, and anemia was almost twice, or more than twice, as high for those receiving transfusions compared to those who had not.
Using propensity score matching, in which the traits of those who had received transfusions was matched with traits of those who had not, 6,116 pairs of cases were analyzed. The participants in these pairs were matched in age, sex, education, income, and health across seven conditions and diseases, including ASCVD, cancer, diabetes, and hypertension.
Researchers found that 2,082 participants who had received blood transfusions died. Over 10.8 years of follow-up, they found, after propensity-score matching, that blood transfusion was associated with nearly double the all-cause mortality rate (hazard ratio [HR] = 1.84; 95% CI 1.33-2.55; p<0.001), and increase in cardiovascular mortality rate (HR=2.37; 95% CI 1.41-3.98; p=0.001). However, they did not find a difference in cancer mortality rate between the groups (HR=0.90; 95% CI 0.40-2.04; p=0.800).
Previous work has suggested that blood transfusion increased the risk of repeated myocardial infarction (MI) and mortality, especially among those with ST-segment elevation MI, and that patients undergoing abdominal surgery had an increased MI incidence 72 hours after perioperative blood transfusion.
These links could be related to inflammatory and immune responses to infusions, which could feed hypercoagulability, researchers said. They cautioned, though, that the study was only observational and doesn’t establish cause.
“Further studies, including subgroup analysis,” they said, “are warranted to define the correlation between blood transfusion and mortality in specific populations.”
Any conflicts of interest declared by the authors can be found in the original article.
Reference
Shi J, Meng M, Sa R, et al. Blood transfusion is correlated with elevated adult all-cause mortality and cardiovascular mortality in the United States: NHANES 1999 to 2018 population-based matched propensity score study. Clinics (Sao Paulo). 2024;79:100379.
