Development and validation of a scoring system to predict vasovagal reaction upon whole-blood donation.

BACKGROUND AND OBJECTIVES: Risk factors for vasovagal reaction (VVR) have been extensively studied. With knowledge of the relative importance of these risk factors for VVR, collection staff could take care of blood donors from the same standpoint, leading to improved donor safety. We therefore developed a scoring system to predict VVR, which incorporates registration information. MATERIALS AND METHODS: Pre-syncopal and syncopal symptoms, as well as on- and off-site reactions, are included in this analysis as VVR. We defined the donor status as follows: first-time donors, repeat donors with no history of reaction and repeat donors with a history of reaction. We prepared two datasets: whole-blood donations at a blood donation site in Tokyo between January 2019 and December 2019 were included in training data (n = 361,114), and whole-blood donations between January 2020 and August 2020 were included in testing data (n = 216,211). RESULTS: The most important variable was the donor status, followed by age, estimated blood volume and height. We integrated them into a scoring system. Training and testing datasets were combined (n = 577,325), and VVR rates in groups with scores of 0, 1, 2, 3, 4 and 5 or more were 0.09% (95% CI: 0.081%-0.10%), 0.33% (95% CI: 0.31%-0.36%), 0.87% (95% CI: 0.78%-0.96%), 1.17% (95% CI: 1.05%-1.30%), 2.15% (95% CI: 1.98%-2.32%) and 3.11% (95% CI: 2.90%-3.34%), respectively. CONCLUSION: The scoring system enables staff to significantly predict VVR and may help them to identify donors at increased risk of experiencing syncope, thereby mitigating the negative impact of VVR on donor safety and return by paying close attention to high-risk donors.

Cord blood index predicts engraftment and early non-relapse mortality in adult patients with single-unit cord blood transplantation.

How to select optimal cord blood (CB) remains an important clinical question. We developed and validated an index of CB engraftment, the cord blood index (CBI), which uses three weighted variables representing cell doses and HLA mismatches. We modeled the neutrophil engraftment time with competing events by random survival forests for competing risks as a function of the predictors: total nucleated cells, CD34, colony-forming units for granulocytes/macrophages, and the number of HLA mismatches at the antigen and allele levels. The CBI defined three groups that had different neutrophil engraftment rates at day 30 (High, 83.7% [95% CI, 79.2-88.1%]; Intermediate, 77.0% [95% CI, 73.7-80.2%]; Low, 68.4% [95% CI, 63.6-73.2%]), platelet engraftment rates at day 60 (High, 70.4% [95% CI, 64.9-75.9%]; Intermediate, 62.3% [95% CI, 58.5-66.0%]; Low, 49.3% [95% CI, 44.2-54.5%]), and non-relapse mortality at day 100 (High, 14.1% [95% CI, 9.9-18.3%]; Intermediate, 16.4% [95% CI, 13.5-19.3%]; Low, 21.3% [95% CI, 17.1-25.5%]). This novel approach is clinically beneficial and can be adopted immediately because it uses easily obtained pre-freeze data of CB.

Syncopal-type reactions tend to be delayed and result in falls among elderly blood donors.

BACKGROUND: Delayed syncopal-type complications are infrequent among blood donors, but sometimes have critical consequences, such as severe injury. We retrospectively investigated the characteristics of donors with delayed syncopal-type complications or falls. STUDY DESIGN AND METHODS: We defined a delayed reaction (DR) as syncopal-type complications occurring >20 min after needle removal. Subjects were stratified by sex, age, estimated blood volume (EBV), body mass index (BMI) and frequency of donation. Multiple logistic regression analysis and propensity score weighted M estimation were performed to evaluate the covariate-adjusted risk of syncopal DRs among donors giving 400 ml of whole blood (WB). The DR rate was calculated as the number of DRs divided by the number of all syncopal-type reactions after needle removal. The risk of falls was assessed similarly. Donors who discontinued before completing phlebotomy (donation of 400 ml) were excluded. RESULTS: Among 3818 syncopal-type reactions after needle removal, there were 359 DRs and 93 falls. Elderly donors and female donors with syncopal-type reactions had a significantly higher risk of DRs (P for trend < 0·001). Elderly donors with syncopal-type reactions also had a higher risk of falls (P for trend < 0·001). Among all donors with syncopal-type reactions, the risk of DRs or falls was not correlated with EBV, BMI or donation frequency. CONCLUSION: In female donors and elderly donors (donating 400 ml of WB), syncopal-type reactions tended to be delayed. Elderly donors with syncopal-type reactions had a significantly higher risk of falls.