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