A risk prediction model for vasovagal reactions in whole blood donors including the physical and psychological factors: Results from a case–control study done in a regional blood transfusion center

Abstract

Abstract: BACKGROUND AND OBJECTIVES: Blood centers strive to maintain a safe and adequate supply of blood products from healthy volunteer donors. Primary responsibility of a medical officer is to assess donor risk for vasovagal reaction (VVR) and alert the phlebotomist. The study attempts to identify the significant risk factors of VVR which may help in decision-making. METHODS: This was a case–control study including blood donors donating 350 ml Whole blood in Department of Transfusion Medicine, Medical College, Thiruvananthapuram from December 19, 2017 to June 31, 2018. Donors who suffered VVRs during or after blood donation were considered as cases and compared with controls. The prevalence of risk factors such as age, sex, number of previous donations, body mass index (BMI), blood volume, sleep duration, food intake, fear and anxiety, and pain perception was compared between the groups. RESULTS: 174 cases and 348 controls were studied. Most of the donors were < 35 years of age (63.2%) younger age groups (18–25 year) had a higher odds of VVR (5.54 with 95% confidence interval [CI] 2.4–12.5). First time donations carried an increased risk of VVR with an ODDs ratio of 5.8 (3.81–9.131) compared to repeat donors. Around 45% of cases were first timers whereas only 12% of controls were first time donors. There was a significantly higher rate of reactions in donors who had episodes of VVRs in the previous donations. Odds 1.99 (CI 1.09–3.74) other risk factors identified were female gender (6.3, 95% CI 2–20), lack of sleep at previous night (32.9; CI 16.17–67.18), and high BMI > 27.5/m2 with odds ratio 2.5 (1.4–4.3). Having an estimated blood volume < 3500 ml also was associated with higher odds of VVRs. CONCLUSION: In spite of having a strict criteria for donor deferral based on risk factors, vasovagal reactions still occur and risk factors are prevalent in blood donor population. Special attention should be given to donors having one more of such risk factors and attempts should be made to avert VVRs.