Analysis of donor return behavior. Retrovirus Epidemiology Donor Study.

BACKGROUND: Efforts to provide a safe, adequate blood supply have been inhibited by persistent shortages attributed to a lack of motivation on the part of the general public and inefficiency in recruiting processes. This study examined whether frequency of donations and/or timing of subsequent donations by first-time donors related to donor demographics. STUDY DESIGN AND METHODS: Characteristics of 879,816 first-time donors making at least one whole-blood donation were analyzed. Cox proportional-hazards regression models evaluated the first 10 return times separately, and a recurrent-event Cox model was applied to simultaneously evaluate the first five returns.
RESULTS: The shorter the donation interval between the first two donations, the more likely the donor was to make subsequent donations. The proportion of repeat donors increased with education level. Rate of donation increased with age and education. The recurrent-event Cox regression model showed that Rh-negative donors, older donors, and donors who had completed college had higher donation return rates.
CONCLUSION: Time to return for second donation was associated with total number of donations made and with return rate for subsequent returns. Age was the strongest predictor of high donation frequency and early-return rate. Relationships between interdonation interval and the number of future donations may prove useful in understanding return behavior and developing donor recruitment and retention strategies.