A case-controlled multicenter study of vasovagal reactions in blood donors: influence of sex, age, donation status, weight, blood pressure, and pulse

BACKGROUND: Vasovagal reactions occur in a small, but significant number of blood donors. These reactions may decrease return donation and disrupt blo od collection activities. The purpose of this study was to define the contr ibutory role of sex, age, weight, blood pressure; and pulse in vasovagal re actions with syncope in blood donors. STUDY DESIGN AND METHODS: A retrospective case-control study involved 1890 blood donors with syncope from three large United States blood centers duri ng 1994 and 1995. Case controls and random population controls were used in a logistic regression analysis to determine the significance of individual variables to syncopal reactions. RESULTS: Female donors, young donors, first-time donors, low-weight donors, and donors with low predonation blood pressure had higher absolute donatio n reaction rates than other donors. When each variable was adjusted for oth er variables by regression analysis, age, weight, and donation status (firs t-time or repeat donor) were significant (p<0.0001), and sex, predonation b lood pressure, and predonation pulse were not. The most important variables , in descending order, were age, weight, and donation status (first-time or repeat donor). CONCLUSIONS: Donation-related vasovagal syncopal reactions are a multifacto rial process determined largely by age, weight, and first-time donor status .