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Trial registered on ANZCTR

Registration number

ACTRN12625000617460

Ethics application status

Approved

Date submitted

30/05/2025

Date registered

13/06/2025

Date last updated

13/06/2025

Date data sharing statement initially provided

13/06/2025

Type of registration

Prospectively registered

Titles & IDs

Public title

Insulin-dextrose vs glucose-only therapy for the treatment of hyperkalaemia

Scientific title

Hypertonic Glucose vs Insulin-dextrose to Prevent HypoGlycaemia following treatment for HyperKalaemia (HIGH K): A randomised controlled trial in adult participants

Secondary ID [1]

Nil known

Universal Trial Number (UTN)

Trial acronym

HIGHK

Linked study record

Health condition

Health condition(s) or problem(s) studied:

Hyperkalaemia

Hypoglycaemia

Condition category

Condition code

Emergency medicine

Other emergency care

Metabolic and Endocrine

Other metabolic disorders

Intervention/exposure

Study type

Interventional

Description of intervention(s) / exposure

Glucose-Only Therapy:
10mL (2.2mmol) calcium gluconate intravenously over 2-3 minutes
10mg salbutamol via nebulisation
100 mL (50%) dextrose administered intravenously over 10 minutes, followed by 250 mL (10%) dextrose administered intravenously over 2 hours.

Interventions will be administered by a registered nurse. Staff will be educated on the trial protocol before the first patient is enrolled. Adherence to protocol will be assessed through retrospective chart review.

Intervention code [1]

Treatment: Drugs

Comparator / control treatment

Insulin-Dextrose Therapy (IDT):
10mL (2.2mmol) calcium gluconate intravenously over 2-3 minutes
10mg salbutamol via nebulisation
10 units intravenous human insulin (Actrapid) with 50 mL (50%) dextrose administered over 10 minutes, followed by 250mL (0.9%) sodium chloride

Interventions will be administered by a registered nurse. Staff will be educated on the trial protocol before the first patient is enrolled. Adherence to protocol will be assessed through retrospective chart review.

Control group

Active

Outcomes

Primary outcome [1]

Incidence of hypoglycaemia defined as blood glucose <3.9 mmol/L.

Timepoint [1]

At basline and then hourly for 6 hours post commencement of treatment.

Primary outcome [2]

Mean change in serum potassium from baseline.

Timepoint [2]

At basline and then at 1 hour, 2 hours (primary timepoint) and 6 hours post commencement of treatment.

Secondary outcome [1]

Hypoglycaemia severity

Timepoint [1]

At basline and then hourly for 6 hours post commencement of treatment.

Secondary outcome [2]

Proportion of participants requiring rescue insulin therapy (insulin administered outside the protocol due to inadequate potassium response (clinician discretion) or due to clinical deterioration).

Timepoint [2]

Recorded anytime the rescue occurs (within the study period of 6 hours) and assessed at the conclusion of the study intervention period.

Secondary outcome [3]

Proportion of participants achieving a clinically significant potassium reduction (defined as greater than or equal to -0.5 mmol/L from baseline).

Timepoint [3]

All patients will have a serum potassium value taken at 2 hours post treatment commencement. The proportion of patients achieving this endpoint will then be assessed at the conclusion of the study intervention period.

Secondary outcome [4]

Presence of hyperkalaemic ECG changes at baseline

Timepoint [4]

The baseline ECG (taken upon presentation to the Emergency Department before any hyperkalaemia treatment options are administered)

Secondary outcome [5]

Insulin levels (mU/L): NB: assay detects both exogenous and endogenous insulin.

Timepoint [5]

Measured at baseline, 1 hour, and 2 hours post commencement of treatment.

Secondary outcome [6]

Resolution of ECG changes

Timepoint [6]

Resolution of baseline ECG changes will be assessed by comparing the baseline ECG data to the ECG taken at 1 hour, 2 hours, and 4-6 hours post treatment.

Eligibility

Key inclusion criteria

Adults (18 years or older), hyperkalaemia (serum or blood gas potassium >5.5 mmol/L), treating ED clinician determines that treatment for hyperkalaemia is necessary and agrees to randomize the patient to one of the treatment arms, ability to provide informed consent or, if the patient lacks capacity, consent obtained from a legally authorised substitute decision-maker.

Minimum age

18 Years

Maximum age

No limit

Sex

Both males and females

Can healthy volunteers participate?

Key exclusion criteria

Diabetes mellitus, pre-treatment blood glucose >7.8 mmol/L, requiring resuscitation, intravenous insulin administered before randomisation, suspected or confirmed intracranial/ intraspinal ischaemic or haemorrhagic stroke, known glucose-galactose malabsorption syndrome, known allergy to corn (maize) and corn products.

Study design

Purpose of the study

Treatment

Allocation to intervention

Randomised controlled trial

Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)

Randomisation to be fascilitated through RedCap randomisation module (randomisation table uploaded into RedCap database).

Methods used to generate the sequence in which subjects will be randomised (sequence generation)

Stratified, block randomisation

Masking / blinding

Blinded (masking used)

Who is / are masked / blinded?

The people receiving the treatment/s
The people administering the treatment/s
The people assessing the outcomes

Intervention assignment

Parallel

Other design features

Phase

Phase 2

Type of endpoint/s

Statistical methods / analysis

A total sample size of 95 participants (approx. 48 per group) was determined to provide 80% power to detect a difference in hypoglycaemia incidence between treatment arms (expected: 17% for insulin–dextrose therapy, 0% for glucose-only), with a=0.05 and up to 10% attrition. A design effect of 1.1 was applied to account for possible repeat enrolments (ICC=0.3, average 1.2 enrolments per participant). This sample size also supports evaluation of non-inferiority for potassium reduction at 2 hours (non-inferiority margin: –0.5 mmol/L; SD: 0.8 mmol/L).

Primary safety (hypoglycaemia incidence) will be compared using Fisher’s exact test; if repeat enrolments introduce clustering, a generalised linear model will be used. For the primary efficacy outcome (potassium change), group means and differences will be reported with 95% confidence intervals, and non-inferiority assessed. Analyses follow a modified intention-to-treat approach. Secondary outcomes will use descriptive statistics and, where applicable, linear mixed-effects models. Missing data will be excluded if minimal (<5%) or handled via mixed modelling. Statistical significance is defined as p<0.05.

Recruitment

Recruitment status

Not yet recruiting

Date of first participant enrolment

Anticipated

2/02/2026

Actual

Date of last participant enrolment

Anticipated

Actual

Date of last data collection

Anticipated

Actual

Sample size

Target

Accrual to date

Final

Recruitment in Australia

Recruitment state(s)

QLD

Recruitment hospital [1]

Royal Brisbane & Womens Hospital - Herston

Recruitment postcode(s) [1]

4029 - Herston

Funding & Sponsors

Funding source category [1]

Hospital

Name [1]

The Royal Brisbane and Women's Hospital

Address [1]

Country [1]

Australia

Primary sponsor type

University

Name

University of Queensland

Address

Country

Australia

Secondary sponsor category [1]

None

Name [1]

Address [1]

Country [1]

Ethics approval

Ethics application status

Approved

Ethics committee name [1]

Metro North Health Human Research Ethics Committee

Ethics committee address [1]

https://metronorth.health.qld.gov.au/research/ethics-and-governance/human-research-ethics-committee

Ethics committee country [1]

Australia

Date submitted for ethics approval [1]

20/01/2025

Approval date [1]

27/05/2025

Ethics approval number [1]

HREC/2025/MNH/115385

Summary

Brief summary

Hyperkalaemia is a potentially life-threatening condition caused by high blood potassium levels. It is commonly treated with insulin and glucose, but insulin can lower blood sugar too much, leading to hypoglycaemia—a condition that can cause confusion, shakiness, or even loss of consciousness. We want to find out whether glucose alone, without insulin, can safely and effectively lower potassium levels in people without diabetes. This may be possible because glucose stimulates the body to produce its own insulin. We are conducting a clinical trial at the Royal Brisbane and Women’s Hospital Emergency and Trauma Centre to compare standard insulin–glucose therapy with glucose-only treatment. The trial will assess both safety (risk of hypoglycaemia) and effectiveness (potassium reduction). If glucose-only therapy is found to be safer and just as effective, it could change the standard treatment for hyperkalaemia.

Trial website

Trial related presentations / publications

Public notes

Contacts

Principal investigator

Name

Dr Julian Williams

Address

Royal Brisbane and Women's Hospital, Emergency and Trauma Centre, Butterfield St, Herston, 4029, QLD

Country

Australia

Phone

+61 417625653

Fax

[email protected]

Contact person for public queries

Name

Samuel Ford

Address

Royal Brisbane and Women's Hospital, Emergency and Trauma Centre, Butterfield St, Herston, 4029, QLD

Country

Australia

Phone

+61 499191700

Fax

[email protected]

Contact person for scientific queries

Name

Samuel Ford

Address

Royal Brisbane and Women's Hospital, Emergency and Trauma Centre, Butterfield St, Herston, 4029, QLD

Country

Australia

Phone

+61 499191700

Fax

[email protected]

Data sharing statement

Will the study consider sharing individual participant data?

What supporting documents are/will be available?

Type	Citation	Link	Email	Other Details	Attachment
Study protocol					HIGHK Protocol 250430 v2 Clean.docx
Ethical approval					115385 HREC Approval Ltr 27.05.2025 Amended 30.05.25.pdf

Results publications and other study-related documents

Documents added manually

No documents have been uploaded by study researchers.

Documents added automatically

No additional documents have been identified.

Trial Review

Documents added manually

Documents added automatically