UMIN-CTR Clinical Trial

Public title

Preventive effect of salt intake at blood donation site on vasovagal reaction.

Acronym

Preventive effect of salt intake at blood donation site on vasovagal reaction.

Scientific Title

A quasi-randomized controlled trial on prevention of delayed vasovagal reaction by salt intake at blood donation site.

Scientific Title:Acronym

A quasi-randomized controlled trial on prevention of delayed vasovagal reaction by salt intake at blood donation site.

Region

Japan

Condition

Vasovagal reaction

Classification by specialty

Cardiology

Blood transfusion

Classification by malignancy

Others

Genomic information

NO

Narrative objectives1

The aim of this trial is to determine if salt intake just before blood donation may prevent delayed vasovagal reaction.

Basic objectives2

Efficacy

Basic objectives -Others

Trial characteristics_1

Confirmatory

Trial characteristics_2

Pragmatic

Developmental phase

Not applicable

Primary outcomes

Incidence of VVR in 3 different phase of blood donation. ( i.e. before needle removal, within 20 minutes after needle removal, and more than 20 minutes after needle removal.).

Key secondary outcomes

Comparison of incidence of VVR after adjustment by age, sex, estimated blood volume, and donation history.

Study type

Interventional

Basic design

Parallel

Randomization

Randomized

Randomization unit

Cluster

Blinding

Open -no one is blinded

Control

No treatment

Stratification

Dynamic allocation

NO

Institution consideration

Institution is considered as a block.

Blocking

YES

Concealment

Pseudo-randomization

No. of arms

2

Purpose of intervention

Prevention

Type of intervention

Food

Interventions/Control_1

Eat 3 candies containing salt (0.108g of salt per 1 candy) prior to blood donation.

Interventions/Control_2

Donate blood according to usual protocol.

Interventions/Control_3

Interventions/Control_4

Interventions/Control_5

Interventions/Control_6

Interventions/Control_7

Interventions/Control_8

Interventions/Control_9

Interventions/Control_10

Age-lower limit

17

years-old

<=

Age-upper limit

69

years-old

>=

Gender

Male and Female

Key inclusion criteria

Eligibility criteria: 1) person who is willing to donate blood and visiting blood donation site, and eligible for blood donation. 2) person who is willing to donate 400mL whole blood.

Key exclusion criteria

Exclusion criteria: Blood donors are excluded from this trial if 1) they are under salt restriction by their doctors, or 2) they are allergic for dairy products, or 3) their informed consent may not be obtained,

Target sample size

458252

Name of lead principal investigator

1st name	Noriko
Middle name
Last name	Namba

Organization

Japanese Red Cross Tokyo Metropolitan Blood Center

Division name

Division of medical affairs

Zip code

162-8639

Address

12-2 Wakamatucho Sihjukuku Tokyo

TEL

0352723532

Email

n-namba@ktks.bbc.jrc.or.jp

Name of contact person

1st name	Noriko
Middle name
Last name	Namba

Organization

Japanese Red Cross Tokyo Metropolitan Blood Center

Division name

Division of medical affairs

Zip code

162-8639

Address

12-2 Wakamatucho Sihjukuku Tokyo

TEL

0352723532

Homepage URL

https://www.bs.jrc.or.jp/ktks/tokyo/2021-028-20240331.pdf

Email

n-namba@ktks.bbc.jrc.or.jp

Institute

Japanese Red Cross Tokyo Metropolitan Blood Center

Institute

Department

Personal name

Organization

Japanese Red Cross Society
Blood Service Headquarter

Organization

Division

Category of Funding Organization

Non profit foundation

Nationality of Funding Organization

Japan

Co-sponsor

Name of secondary funder(s)

Organization

Japanese Red Cross Society Blood Service Headquater Central Blood Institute

Address

2-1-67 Tatsumi Koto-ku Tokyo

Tel

0355347508

Email

kenkyu1@jrc.or.jp

Secondary IDs

NO

Study ID_1

Org. issuing International ID_1

Study ID_2

Org. issuing International ID_2

IND to MHLW

Institutions

Date of disclosure of the study information

2022

Year

03

Month

01

Day

URL releasing protocol

doi: 10.1111/vox.70273

Publication of results

Published

URL related to results and publications

doi: 10.1111/vox.70273

Number of participants that the trial has enrolled

540621

Results

The incidence of delayed syncopal vasovagal reactions (VVRs) did not differ significantly between the two groups (0.012% vs. 0.009%; odds ratio [OR], 0.80; 95% confidence interval [CI], 0.5-1.4; p = 0.42).
During the summer season, the incidence of delayed syncopal VVRs was lower in the salt-loading group (0.008% [n = 8] vs. 0.001% [n = 1]; OR, 0.13; p = 0.04), although the predefined significance level was set at p = 0.0125.

Results date posted

2026

Year

08

Month

20

Day

Results Delayed

Results Delay Reason

Date of the first journal publication of results

Baseline Characteristics

Age (mean) 41.8 41.5 0.02
EBV (L, mean) 4.79 4.79 0.01
Sex
Male 69.0% 70.0% 0.02
Female 31.0% 30.0% 0.02
Donation history
First time 5.05% 5.12% 0.003
Repeat 94.8% 94.6% 0.003
Lapseda 0.27% 0.27% <0.001

Participant flow

Participants of the salt-loading group were asked to take three salt-containing candies (Enbun-charge tablets, Kabaya Foods Corporation, Okayama, Japan) before donation. The 'Enbun charge tablets' are commercially available candies sold in many places such as grocery stores in Japan. It is a melt-in-your-mouth yet hard candy and consumed mainly in summer as supplements of salt. It tastes like isotonic water. Each tablet contains 0.1 g of salt. The amount of salt contained in three tablets is equivalent to 300-500 mL of a typical isotonic drink. The number of tablets taken before donation was recorded. Blood donation rooms in Tokyo are equipped with free vending machines and donors can choose drinks from a variety of beverages, which are considered one of the perks of blood donation there. Isotonic drink was not chosen in this study so as not to deprive the small joy from our donors.
The brochure provided to the control group contained an overview of the study, instructions to contact the blood centre if any adverse symptoms occurred after donation and the principal investigator's contact information, along with a website Uniform Resource Locator and two-dimensional barcode directing participants to further study information. The website contained information largely comparable to that provided to the salt-loading group and clearly outlined the opt-out procedure. The exclusion criteria applied to the salt group were not included in the information given to the control group.
Adverse events including VVRs are recorded according to Standard Operational Procedures of JRCBS. The onset of each VVR is supposed to be categorized based on minutes past after the needle removal and recorded. Off-site reactions were recorded only when reported by donors.

Adverse events

No unexpected adverse events were observed.

Outcome measures

Note:
Period A: Before needle removal
Period B: Within 20 min after needle removal
Period C: More than 20 min after needle removal
Abbreviations:
CI: Confidence interval
OR: Odds ratio
VVR: Vasovagal reaction
The incidence of syncopal VVR occurring in Period C was not significantly different between the two groups (0.012% vs. 0.009%; OR 0.80; 95% CI 0.5-1.4; p = 0.42; Table 2a, Figure 2).
Similarly, the incidence of non-syncopal VVR did not differ significantly between the groups (0.046% vs. 0.044%; OR 0.96; 95% CI 0.7-1.2; p = 0.73).
For Period B, there were no significant differences between the two groups in the incidence of syncopal VVR (0.026% vs. 0.023%; OR 0.86; 95% CI 0.6-1.2; p = 0.41; Table 2a, Figure 2) or non-syncopal VVR (0.238% vs. 0.242%; OR 1.02; 95% CI 0.9-1.1; p = 0.73; Table 2b, Figure 2).
Likewise, in Period A, no significant differences were observed in syncopal VVR (0.017% vs. 0.020%; OR 1.20; 95% CI 0.8-1.8; p = 0.38; Table 2a, Figure 2) or non-syncopal VVR (0.17% vs. 0.15%; OR 0.88; 95% CI 0.7-1.1; p = 0.60; Table 2b, Figure 2).
In contrast, an inverse correlation was observed between the incidence of delayed VVR (dVVR, defined as VVR occurring in Period C) and the number of salt tablets consumed (OR 0.70; 95% CI 0.52-0.944; p = 0.019; Figure 3c). In other words, the incidence of dVVR tended to decrease as the number of consumed salt tablets increased.
However, no association was observed between the number of salt tablets consumed and VVR occurring in Period B (OR 0.92; 95% CI 0.78-1.08; p = 0.33; Figure 3b). Likewise, no association was observed with VVR occurring in Period A (OR 1.04; 95% CI 0.83-1.29; p = 0.71).
During the summer season, fewer delayed syncopal VVRs were observed in the salt-loading group (0.008% [n = 8] vs. 0.001% [n = 1]; OR 0.13; p = 0.04). However, the predefined significance level for multiple comparisons was p = 0.0125.
In the analysis of summer delayed syncopal VVR (dVVR), the post hoc power was 0.42 with Bonferroni adjustment and 0.88 without Bonferroni adjustment.

Plan to share IPD

IPD sharing Plan description

Recruitment status

Completed

Date of protocol fixation

2021

Year

12

Month

17

Day

Date of IRB

2021

Year

12

Month

17

Day

Anticipated trial start date

2022

Year

03

Month

15

Day

Last follow-up date

2024

Year

09

Month

30

Day

Date of closure to data entry

Date trial data considered complete

Date analysis concluded

Other related information

Registered date

2022

Year

02

Month

14

Day

Last modified on

2026

Year

08

Month

20

Day

Link to view the page

Value
https://center6.umin.ac.jp/cgi-open-bin/icdr_e/ctr_view.cgi?recptno=R000053494