Di Angelantonio E, et al. - A randomised trial is done to assess the impact of different inter-donation intervals on blood supply and donor health over a 2-year period. More than 2 years, more frequent donation than is standard practice in the UK collected substantially more blood without having a major effect on donors' quality of life, physical activity, or cognitive function, but resulted in more donation-related symptoms, deferrals, and iron deficiency.

Methods

• For this study, they conducted a parallel group, pragmatic, randomised trial.
• In this trial, they selected whole blood donors aged 18 years or older from 25 centers across England, UK.
• By utilization of a computer-based algorithm, men were randomly assigned (1:1:1) to 12-week (standard) versus 10-week versus 8-week inter-donation intervals, and women were randomly assigned (1:1:1) to 16-week (standard) versus 14-week versus 12-week intervals.
• Participants were not masked to their allocated intervention group.
• The primary outcome was the number of donations more than 2 years.
• Secondary outcomes related to safety were the quality of life, symptoms potentially associated with donation, physical activity, cognitive function, haemoglobin and ferritin concentrations, and deferrals because of low haemoglobin.

Results

• Between June 11, 2012 to June 15, 2014, total 45263 whole blood donors were selected.
• Out of these 45263 whole blood donors, 22466 were men and 22797 were women.
• In this study, data were investigated for 45042 (99·5%) participants.
• Men were randomly assigned to the 12-week (n=7452) versus 10-week (n=7449) versus 8-week (n=7456) groups; and women to the 16-week (n=7550) versus 14-week (n=7567) versus 12-week (n=7568) groups.
• In men, compared with the 12-week group, the mean amount of blood collected per donor over 2 years increased by 1·69 units (95% CI 1·59-1·80; approximately 795 mL) in the 8-week group and by 0·79 units (0·69-0·88; approximately 370 mL) in the 10-week group (p<0·0001 for both).
• In women, compared with the 16-week group, it increased by 0·84 units (95% CI 0·76-0·91; approximately 395 mL) in the 12-week group and by 0·46 units (0·39-0·53; approximately 215 mL) in the 14-week group (p<0·0001 for both).
• There were no significant differences in quality of life, physical activity, or cognitive function across randomised groups.
• However, more frequent donation resulted in more donation-related symptoms (eg, tiredness, breathlessness, feeling faint, dizziness, and restless legs, particularly among men [for all listed symptoms]), lower mean haemoglobin and ferritin concentrations, and more deferrals for low haemoglobin (p<0·0001 for each) than those observed in the standard frequency groups.