Efficiency and safety of varying the frequency of whole blood donation (INTERVAL): a randomised trial of 45 000 donors
Authors: Emanuele Di Angelantonio, Simon G Thompson, Stephen Kaptoge, Carmel Moore, Matthew Walker, Jane Armitage, Willem H Ouwehand, David J Roberts, John Danesh, Emanuele Di Angelantonio, Simon G Thompson, Stephen Kaptoge, Carmel Moore, Matthew Walker, Jane Armitage, Willem H Ouwehand, David J Roberts, John Danesh, Jane Armitage, John Danesh, Emanuele Di Angelantonio, Jenny Donovan, Ian Ford, Rachel Henry, Beverley J Hunt, Bridget Le Huray, Susan Mehenny, Gail Miflin, Carmel Moore, Willem H Ouwehand, Jane Green, David J Roberts, Mike Stredder, Simon G Thompson, Matthew Walker, Nicholas A Watkins, Alan McDermott, Clive Ronaldson, Claire Thomson, Zoe Tolkien, Lorna Williamson, David Allen, John Danesh, Emanuele Di Angelantonio, Rachel Henry, Susan Mehenny, Carmel Moore, Willem H Ouwehand, David J Roberts, Jennifer Sambrook, Matthew Walker, Tracey Hammerton, Claire Thomson, Zoe Tolkien, David Allen, David Bruce, Fizzah Choudry, Emanuele Di Angelantonio, Cedric Ghevaert, Kirstie Johnston, Anne Kelly, Andrew King, Susan Mehenny, Gail Miflin, Alfred Mo, Carmel Moore, Willem H Ouwehand, Lizanne Page, Penny Richardson, David J Roberts, Jennifer Sambrook, Peter Senior, Yagnesh Umrania, Matthew Walker, Henna Wong, Stephen Kaptoge, Gavin Murphy, Adrian C Newland, Keith Wheatley, Michael Greaves, Marc Turner, Tahir Aziz, Richard Brain, Christine Davies, Ruth Turner, Paula Wakeman, Alison Dent, Alan Wakeman, Ben Anthony, Desmond Bland, Will Parrondo, Helen Vincent, Candy Weatherill, Andrea Forsyth, Carol Butterfield, Tracey Wright, Karen Ellis, Kirstie Johnston, Pat Poynton, Carolyn Brooks, Emma Martin, Lara Littler, Lindsay Williams, Donna Blair, Karen Ackerley, Lynn Woods, Sophie Stanley, Gemma Walsh, Gayle Franklin, Cheryl Howath, Sarah Sharpe, Deborah Smith, Lauren Botham, Caroline Williams, Claire Alexander, Gareth Sowerbutts, Diane Furnival, Michael Thake, Shilpa Patel, Carolyn Roost, Sandra Sowerby, Mary Joy Appleton, Eileen Bays, Geoff Bowyer, Steven Clarkson, Stuart Halson, Kate Holmes, Gareth Humphries, Kirstie Johnston, Lee Parvin-Cooper, Jason Towler, Joanne Addy, Patricia Barrass, Louise Stennett, Susan Burton, Hannah Dingwall, Rachel Henry, Victoria Clarke, Maria Potton, Claire Thomson, Thomas Bolton, Michael Daynes, Stuart Halson, Sarah Spackman, Matthew Walker, Abudu Momodu, James Fenton, Adam King, Omer Muhammed, Nicholas Oates, Tim Peakman, Christine Ryan, Kristian Spreckley, Craig Stubbins, Joanna Williams, James Brennan, Cedric Mochon, Samantha Taylor, Kimberley Warren, Stephen Kaptoge, Simon G Thompson, Emanuele Di Angelantonio, Carmel Moore, Jonathan Mant, Willem H Ouwehand, Simon G Thompson, John Danesh, David J Roberts
Journal: The Lancet (2017)

BackgroundLimits on the frequency of whole blood donation exist primarily to safeguard donor health. However, there is substantial variation across blood services in the maximum frequency of donations allowed. We compared standard practice in the UK with shorter inter-donation intervals used in other countries.MethodsIn this parallel group, pragmatic, randomised trial, we recruited whole blood donors aged 18 years or older from 25 centres across England, UK. By use 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 over 2 years. Secondary outcomes related to safety were quality of life, symptoms potentially related to donation, physical activity, cognitive function, haemoglobin and ferritin concentrations, and deferrals because of low haemoglobin. This trial is registered with ISRCTN, number ISRCTN24760606, and is ongoing but no longer recruiting participants.Findings45 263 whole blood donors (22 466 men, 22 797 women) were recruited between June 11, 2012, and June 15, 2014. Data were analysed for 45 042 (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). No significant differences were observed 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, especially 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.InterpretationOver 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.FundingNHS Blood and Transplant, National Institute for Health Research, UK Medical Research Council, and British Heart Foundation.