Evidence map›Paper›PMID 28941948›Full record

Trial reportLancet (London, England)2017

Efficiency and safety of varying the frequency of whole blood donation (INTERVAL): a randomised trial of 45 000 donors.

Emanuele Di Angelantonio, Simon G Thompson, Stephen Kaptoge, Carmel Moore, Matthew Walker, Jane Armitage, Willem H Ouwehand, David J Roberts, John Danesh, INTERVAL Trial Group

Open access · hybridAbstract readMulticenter StudyRandomized Controlled TrialPragmatic Clinical Trial
PubMed Full text at PMC Publisher
In one paragraph

Trial report in Lancet (London, England), 2017. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 140 papers, 10 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
140citing papers in PubMed, 10 pooled it
55.3field-weighted citation impact, top 1% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

140 citing papers in PubMed, 10 syntheses or guidelines pooled it, 294 citations in OpenAlex.

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  3. Impact ofFrontiers in microbiology · 2025
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  19. The price of blood is measured in iron.Lancet (London, England) · 2017
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80 more citing papers are in PubMed but not listed here.

4 · The record

Corrections and comments

5 · Who and what money

Authors and funding

10 authors at 7 institutions in 1 country.

Emanuele Di AngelantonioNHS Blood and Transplant, Cambridge, UK; NHS Blood and Transplant, Oxford, UK; Department of Public Health and Primary Care, Strangeways Research Laboratory, Cambridge, UK; NIHR Blood and Transplant Research Unit in Donor Health and Genomics, Strangeways Research Laboratory, Cambridge, UK; NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, UK; British Heart Foundation Cambridge Centre for Research Excellence, Addenbrooke's Hospital, Cambridge, UK.
Simon G ThompsonDepartment of Public Health and Primary Care, Strangeways Research Laboratory, Cambridge, UK; NIHR Blood and Transplant Research Unit in Donor Health and Genomics, Strangeways Research Laboratory, Cambridge, UK; NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, UK; British Heart Foundation Cambridge Centre for Research Excellence, Addenbrooke's Hospital, Cambridge, UK.
Stephen KaptogeDepartment of Public Health and Primary Care, Strangeways Research Laboratory, Cambridge, UK; NIHR Blood and Transplant Research Unit in Donor Health and Genomics, Strangeways Research Laboratory, Cambridge, UK; NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, UK; British Heart Foundation Cambridge Centre for Research Excellence, Addenbrooke's Hospital, Cambridge, UK.
Carmel MooreDepartment of Public Health and Primary Care, Strangeways Research Laboratory, Cambridge, UK; NIHR Blood and Transplant Research Unit in Donor Health and Genomics, Strangeways Research Laboratory, Cambridge, UK; NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, UK; British Heart Foundation Cambridge Centre for Research Excellence, Addenbrooke's Hospital, Cambridge, UK.
Matthew WalkerDepartment of Public Health and Primary Care, Strangeways Research Laboratory, Cambridge, UK; NIHR Blood and Transplant Research Unit in Donor Health and Genomics, Strangeways Research Laboratory, Cambridge, UK; NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, UK; British Heart Foundation Cambridge Centre for Research Excellence, Addenbrooke's Hospital, Cambridge, UK.
Jane ArmitageClinical Trial Service Unit and Epidemiological Studies Unit, Nuffield Department of Population Health, University of Oxford, Oxford, UK; MRC Population Health Research Unit, University of Oxford, Oxford, UK.
Willem H OuwehandNHS Blood and Transplant, Cambridge, UK; NHS Blood and Transplant, Oxford, UK; British Heart Foundation Cambridge Centre for Research Excellence, Addenbrooke's Hospital, Cambridge, UK; Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK.
David J RobertsNHS Blood and Transplant, Cambridge, UK; NHS Blood and Transplant, Oxford, UK; NIHR Blood and Transplant Research Unit in Donor Health and Genomics, Strangeways Research Laboratory, Cambridge, UK; NIHR Oxford Biomedical Research Centre-Haematology Theme and Radcliffe Department of Medicine, University of Oxford, John Radcliffe Hospital, Oxford, UK.
John DaneshDepartment of Public Health and Primary Care, Strangeways Research Laboratory, Cambridge, UK; NIHR Blood and Transplant Research Unit in Donor Health and Genomics, Strangeways Research Laboratory, Cambridge, UK; NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, UK; British Heart Foundation Cambridge Centre for Research Excellence, Addenbrooke's Hospital, Cambridge, UK. Electronic address: jd292@medschl.cam.ac.uk.
INTERVAL Trial Group
Genomics (United Kingdom) · GBAddenbrooke's Hospital · GBBritish Heart Foundation · GBUniversity of Oxford · GBNHS Blood and Transplant · GBJohn Radcliffe Hospital · GBUniversity of Cambridge · GB

Funding

British Heart Foundation CH/12/2/29428British Heart Foundation FS/09/039/27788British Heart Foundation RG/08/014/24067British Heart Foundation RG/13/13/30194British Heart Foundation RG/16/4/32218Department of Health RP-PG-0310-1004Medical Research Council MC_UU_12026/5Medical Research Council MR/L003120/1Medical Research Council MR/P013880/1Medical Research Council MR/P02811X/1
6 · The paper itself

Abstract

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.

Indexed as

EfficiencyPatient SafetyAdultAge FactorsAnemia, Iron-DeficiencyBlood DonorsFemaleFerritinsHumansMaleMiddle AgedRisk AssessmentSex FactorsTime FactorsUnited KingdomYoung AdultFerritins

Identifiers

PMID28941948
PMCPMC5714430
OpenAlexW2755213026

What OpenQuestion holds

Textmetadata
LicenceCC BY
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.