An intervention study for the prevention of vasovagal reactions and evaluating donors' experience: Analysis of donors' return for subsequent donation

The EPISoDe (Experience Success in Donation) study investigated the effect of interventions on self-reported vasovagal reactions (VVRs) in first-time and novice (second to fourth donation) whole blood donors aged ≤30 years, demonstrating a 23% reduction of VVR from water drinking shortly before donation in the novice donors. Because donation experience and complications affect donor retention, we analysed intervention group donors' return for subsequent donation, a predefined secondary outcome.The interventions were as follows: 330 ml water, 500 ml water, ball squeezing before phlebotomy (placebo) and a control group. All donors received an online questionnaire about their experience within a week after donation. In the Netherlands, eligible donors are invited at least yearly depending on hospitals' needs. We analysed attendances within 421 days through return percentages and binomial logistic regression.Of the 8300 EPISoDe participants, 6538 (78.8%) returned within 421 days. Return did not differ between the two water groups, whereas odds for return were significantly higher in both water and placebo intervention donors compared to the control group (odds ratio [OR] 1.14, 95% confidence interval [CI] 1.00-1.29 and 1.22, 1.05-1.43, respectively) after adjustment for occurrence of VVR, unsuccessful collection, gender and donation history. Staff-recorded or self-reported VVR at index donation was associated with reduced odds for return (OR 0.47, 95% CI 0.37-0.60 and OR 0.53, 95% CI 0.46-0.61, respectively).In this cohort of younger inexperienced blood donors, 78.8% returned for subsequent donation. Donors who received an active study intervention, either water or placebo, were more likely to return than control group donors.