UMIN-ICDS Clinical Trial
| Unique ID issued by UMIN | UMIN000063213 |
|---|---|
| Receipt number | R000069615 |
| Scientific Title | Impact of Low-Potassium Lettuce Intake on Serum Potassium and Safety Outcomes: Randomized Controlled Trials in Patients with Chronic Kidney Disease |
| Date of disclosure of the study information | 2026/10/08 |
| Last modified on | 2026/10/08 00:53:35 |
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Basic information
Public title
Effects of Low-Potassium Lettuce Intake on Serum Potassium Levels in Patients with Chronic Kidney Disease: A Clinical Study
Acronym
Low-K Lettuce Trial
Scientific Title
Impact of Low-Potassium Lettuce Intake on Serum Potassium and Safety Outcomes: Randomized Controlled Trials in Patients with Chronic Kidney Disease
Scientific Title:Acronym
L-K Lettuce RCT
Region
| Japan |
Condition
Condition
Hyperkalemia in patients with chronic kidney disease
Classification by specialty
| Nephrology |
Classification by malignancy
Others
Genomic information
NO
Objectives
Narrative objectives1
To clarify the effects of low-potassium lettuce intake on serum potassium levels and safety outcomes in patients with chronic kidney disease.
Basic objectives2
Safety,Efficacy
Basic objectives -Others
Trial characteristics_1
Exploratory
Trial characteristics_2
Others
Developmental phase
Not applicable
Assessment
Primary outcomes
Change in serum potassium concentration from baseline to the end of the 4day intervention.
Key secondary outcomes
Change in 24hour urinary potassium excretion before and after the intervention
Changes in other serum electrolytes (sodium, calcium, phosphate)
Incidence of adverse events, including hyperkalemia and gastrointestinal symptoms
Base
Study type
Interventional
Study design
Basic design
Parallel
Randomization
Randomized
Randomization unit
Individual
Blinding
Double blind -all involved are blinded
Control
Active
Stratification
NO
Dynamic allocation
NO
Institution consideration
Institution is not considered as adjustment factor.
Blocking
NO
Concealment
Central registration
Intervention
No. of arms
2
Purpose of intervention
Treatment
Type of intervention
| Food |
Interventions/Control_1
Participants consume 100 g of low-potassium lettuce once daily during the intervention period (Trial 1: 4 days; Trial 2: during the interdialytic interval). The lettuce is consumed raw, and no additional dietary restrictions are imposed beyond routine clinical guidance.
Interventions/Control_2
Participants consume 100 g of standard lettuce once daily during the intervention period (Trial 1: 4 days; Trial 2: during the interdialytic interval). The lettuce is consumed raw in the same manner as the intervention group.
Interventions/Control_3
Interventions/Control_4
Interventions/Control_5
Interventions/Control_6
Interventions/Control_7
Interventions/Control_8
Interventions/Control_9
Interventions/Control_10
Eligibility
Age-lower limit
| 20 | years-old | <= |
Age-upper limit
| 120 | years-old | >= |
Gender
Male and Female
Key inclusion criteria
Adults aged 20 years or older with chronic kidney disease (Trial 1) or undergoing maintenance hemodialysis (Trial 2)
Ability to provide written informed consent
Stable clinical condition with serum potassium levels deemed acceptable for study participation by the treating physician
Key exclusion criteria
Severe hyperkalemia or any condition judged by the treating physician to make study participation unsafe
Acute illness, active infection, or clinically unstable conditions requiring hospitalization
Inability to collect accurate 24hour urine samples (Trial 1 only)
Known food allergies or other conditions that prevent lettuce consumption
Inability to provide written informed consent
Target sample size
40
Research contact person
Name of lead principal investigator
| 1st name | Yosuke |
| Middle name | |
| Last name | Nakayama |
Organization
Kurume University School of Medicine
Division name
Division of Nephrology, Department of Medicine
Zip code
8300011
Address
67 Asahi machi, Kurume, Fukuoka, Japan
TEL
81942317763
nakayama_yosuke@med.kurume-u.ac.jp
Public contact
Name of contact person
| 1st name | Yosuke |
| Middle name | |
| Last name | Nakayama |
Organization
Kurume University School of Medicine
Division name
Division of Nephrology, Department of Medicine
Zip code
8300011
Address
67 Asahi machi, Kurume, Fukuoka, Japan
TEL
81942317763
Homepage URL
nakayama_yosuke@med.kurume-u.ac.jp
Sponsor or person
Institute
Kurume University School of Medicine
Institute
Department
Personal name
Yosuke Nakayama
Funding Source
Organization
Kurume University School of Medicine
Organization
Division
Category of Funding Organization
Other
Nationality of Funding Organization
Japan
Other related organizations
Co-sponsor
None
Name of secondary funder(s)
None
IRB Contact (For public release)
Organization
Ethics Committee, Kurume University School of Medicine
Address
67 Asahi machi, Kurume, Fukuoka, Japan
Tel
81942317544
info@kurume-u.ac.jp
Secondary IDs
Secondary IDs
NO
Study ID_1
Org. issuing International ID_1
Study ID_2
Org. issuing International ID_2
IND to MHLW
Institutions
Institutions
久留米大学病院（福岡県）
Other administrative information
Date of disclosure of the study information
| 2026 | Year | 10 | Month | 08 | Day |
Related information
URL releasing protocol
Publication of results
Partially published
Result
URL related to results and publications
Number of participants that the trial has enrolled
10
Results
Primary Outcome (Serum Potassium Level) The low potassium lettuce group showed a significant reduction in serum potassium levels after the intervention.
Secondary Outcomes (Safety)No adverse events occurred during the intervention period.
Results date posted
| 2026 | Year | 10 | Month | 08 | Day |
Results Delayed
| Delay expected |
Results Delay Reason
Although the final analysis of this trial has been completed, preparation of the manuscript for journal submission has required additional time, resulting in delayed reporting on UMIN. Interim results have already been presented at a scientific conference, and the final results will be disclosed after submission to the international journal Nutrients.
Date of the first journal publication of results
| 2019 | Year | 04 | Month | 10 | Day |
Baseline Characteristics
Participants were non dialysis chronic kidney disease (CKD) patients, and baseline characteristics were well balanced between the intervention (low potassium lettuce) and control groups.
Participant flow
Ten participants were screened for eligibility, and all were enrolled. All 10 participants were randomized 5 to the standard lettuce group and 5 to the low potassium lettuce group.
Adverse events
No adverse events occurred during the intervention period. No gastrointestinal symptoms (such as abdominal pain, diarrhea, or nausea) were observed, and there was no deterioration in renal function or development of hyperkalemia. Blood pressure, body weight, and urinalysis parameters showed no clinically relevant changes, indicating that the intervention was well tolerated and safe.
Outcome measures
Primary outcome
The primary outcome was the change in serum potassium levels before and after the intervention.
Secondary outcomes
Secondary outcomes included safety and related parameters:
Occurrence of adverse events
Changes in renal function (eGFR and serum creatinine)
Changes in blood pressure and body weight
Changes in urinary sodium excretion (urinary Na)
Plan to share IPD
There is no plan to share individual participant data (IPD).
IPD sharing Plan description
Individual participant data (IPD) collected in this study will not be shared with third parties due to concerns regarding personal privacy. Clinical variables such as serum potassium levels, renal function parameters (eGFR and serum creatinine), and urinary sodium excretion may allow potential identification of participants even after anonymization; therefore, IPD will not be made publicly available. However, anonymized aggregate data may be provided upon reasonable request for the purpose of secondary analysis or verification of the study findings. The principal investigator will review each request, and data will be shared only when it is deemed ethically appropriate and when participant confidentiality can be fully protected.
Progress
Recruitment status
Completed
Date of protocol fixation
| 2016 | Year | 08 | Month | 23 | Day |
Date of IRB
| 2016 | Year | 08 | Month | 23 | Day |
Anticipated trial start date
| 2016 | Year | 08 | Month | 23 | Day |
Last follow-up date
| 2017 | Year | 06 | Month | 30 | Day |
Date of closure to data entry
| 2017 | Year | 06 | Month | 30 | Day |
Date trial data considered complete
| 2017 | Year | 06 | Month | 30 | Day |
Date analysis concluded
| 2017 | Year | 12 | Month | 30 | Day |
Other
Other related information
Management information
Registered date
| 2026 | Year | 10 | Month | 08 | Day |
Last modified on
| 2026 | Year | 10 | Month | 08 | Day |
Link to view the page
Value
https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000069615
