OA3-AM24-SN-15 - Predictors of Off-site Loss of Consciousness or Major Injury Across the Donor Age Spectrum

Previous studies have shown that vasovagal reactions (VVR) including faint and pre-faint events are higher among younger donors. Currently, fluid intake & muscle tension interventions to prevent VVRs are limited to collection sites, and minimum estimated blood volume (EBV) restrictions are only in place for < 23-year-old (y/o) donors. This analysis explores rarer donor events classified as off-site LOC (LOCoffsite) events and/or Major Injuries (MI) across various donor ages, particularly among ≥75 y/o donors to help understand risk factors and further improve donor safety.

Study

Design/Methods:

We analyzed donor adverse events recorded between 2019-2023 among allogeneic needle-in donations across our blood establishment.  We compared proportions of a composite outcome of LOCoffsite/MI events across donor age (defining MI as one or a combination of closed head injury, concussion, dental injury, laceration, fracture, motor vehicle accident, soft tissue injury or other). We also summarized the distribution of LOCoffsite/MI among ≥75y/o donors stratified by sex and collection type. We performed multivariate logistic regression analysis (MVA) on predictors of LOCoffsite/MI including donor factors previously associated with VVRs (sex, age, EBV, donor experience, race-ethnicity, pulse and systolic BP [SBP]).

Results/Findings:

During the 5-year period, 4,749,358 allogeneic needle-in donations were analyzed. We identified 543 LOCoffsite/MI events with overall rate 1.1 per 10K (higher among females compared to males [1.9 vs. 0.4 per 10K], p< 0.0001). Separately, there were 112 MI events (0.24 per 10K) and 454 LOCoffsite (0.96 per 10K). Among ≥75y/o donors the LOCoffsite/MI rate was 2.1 per 10K and females had statistically significantly higher proportions of LOCoffsite/MI compared to male donors (3.9 vs. 1.9 per 10K, p< 0.0001) (Figure A1). There was no difference in LOCoffsite/MI between whole blood or automated collections (2.3 vs. 1.5 per 10K, p=0.28).  

In MVA for LOCoffsite/MI, donors ≥65y/o had a higher adjusted odds ratio (aOR) (vs. 35-39 y/o) with the highest prevalence among ≥75y/o donors aOR 3.42 (95% CI 2.10-5.57) with females higher at aOR 2.01 (1.46-2.27) vs. males. First-time and lapsed donors had higher aORs 2.54 (2.05-3.15) and 1.37 (1.02-1.83), respectively compared to repeat donors. Donors with pulse < 65bpm had decreased aOR 0.64 (0.50-0.83) (vs. 65-90 bpm); all donors with EBV < 5L (vs. ≥5L) had higher aORs, highest among those with < 3.5L aOR 4.38 (2.85-6.74). SBP >140mmHg had a lower aOR (0.71 (0.55-0.92) (vs. 100-139) (Figure A2).

Conclusions:

Current VVR mitigation efforts may be contributing to the overall rarity of LOCoffsite/MI. However, a closer review of potential efforts to further protect older female donors with lower EBV, especially once they leave the collection site, may be warranted.