Vasovagal reactions in 'at risk' donors: a univariate analysis of effect of age and weight on the grade of donor reactions.

INTRODUCTION: It is well known that young age, low weight, and first time donation status increase the probability of having a reaction but the effect of these 'risk' factors on the grade of reaction has not been well studied. AIM: To evaluate the prevalence of these factors in blood donation setup, to identify 'at risk' donors with age less than 30 years and weight less than 60 kg and to assess whether there is any contributory role of these risk factors in predicting the grade of reaction.
MATERIALS AND METHODS: A retrospective analysis of 30370 donations was done during 15 month study period.
RESULTS: Donor reaction rate of 1.6% was observed in this study of which 7% experienced reaction of moderate and severe grade. Reaction rate among male and female donors were 1.5% and 3.7% respectively. Female gender was found to be an independent predictor for donor reaction even after nullifying the effect of the blood volume drawn. Incidence of vasovagal reaction in 'at risk' donors was 2.0% in contrast to 0.96% in 'general' donor population. Age had a significant affect on reaction rate (p = .035) and all grades of reaction decreased with the age of the donor. Age was found to be a significant predictor of the grade of reaction (p = .008). The effect of weight on the reaction rate as well as on the grade was found to be insignificant (1.5% in 'at risk' donors vs. 1.6% in 'general' donors with p > 0.05).
CONCLUSION: 1. Age is a significant factor that can predict the rate as well as the grade of reaction; 2. Weight does not predict the grade of reaction, 3. Gender is an independent predictor of donor reaction, with females having 2.5 fold higher chances of reaction. These factors are important for blood collection staff to recognize such 'at risk' donors, and to give more attention to them to reduce donor reaction.