The impact of temporary deferral due to low hemoglobin: future return, time to return, and frequency of subsequent donation

Abstract

BACKGROUND: This study investigated the effects of a 6-month deferral due to low hemoglobin (Hb) on the subsequent donation patterns of Australian whole blood donors. STUDY DESIGN AND METHODS: The study was a retrospective cohort study of the donation patterns of all whole blood donors deferred for low Hb during a 2-month period compared with donors who were not deferred. Donations 3 years after eligibility to give blood were recorded. Analysis of proportion returning, time to return, and frequency of donation was performed using logistic regression, survival analysis, and negative binomial regression. RESULTS: Among first-time donors, 20.9% of low Hb–deferred donors returned during the follow-up period versus 69.9% of those not deferred. Among repeat donors, 64.0% of deferred donors returned versus 91.0% of those not deferred. Temporary deferral delayed time to first return (p < 0.001), reduced frequency of donation (2.4 donations per donor before deferral compared to 1.1 per donor in first year of follow-up), and increased the likelihood of dropping out in later years of follow-up. However, if a donor returned promptly once eligible and gave more donations in the first year, the negative impact on future donation patterns was diminished. High frequency of attendance before deferral was the strongest predictor of time to return and future donation frequency. CONCLUSION: Deferral for low Hb had a strong effect on first-time and repeat donors. This study highlights the influence of strong donation habits on return after deferral and the importance of encouraging donors to return promptly once eligible.