Protocolised Management of Phosphate Replacement Trial (PROMPT)

A Comparison of Two Phosphate Replacement Protocols for Critically Ill Patients Treated in an Intensive Care Unit: a Cluster, Crossover, Comparative Effectiveness, Randomised, Controlled Trial

The aim of this cluster, crossover, randomised controlled trial is to compare two standard arms of treatment for the replacement of phosphate in critically ill patients.

We hypothesise that protocolised restricted phosphate replacement, compared to protocolised liberal phosphate replacement, will result in reduced administration of phosphate with similar clinical outcomes.

All eligible Intensive Care Unit (ICU) patients will be included during their admission with the selected protocol for that period as per usual practice and treatment standards.

Study Overview

• Status: Not yet recruiting
• Conditions: Hypophosphatemia; Critical Care, Intensive Care; Phosphate Deficiency; Protocol Optimization
• Intervention / Treatment: Other: Liberal Phosphate Replacement Protocol; Other: Restrictive Phosphate Replacement Protocol

Detailed Description

This study looks to compare liberal and restrictive phosphate replacement protocols (each arm is a current "standard of care" already used in practice) to investigate whether restrictive phosphate replacement in critically ill patients leads to reduced phosphate administration and/or equivalent patient outcomes.

Derangements of serum phosphate concentrations are common among ICU patients; high and low levels variably associated with worse outcomes. The PROMPT trial will compare two standard arms of treatment for the replacement of phosphate in critically ill patients. Phosphate is currently replaced routinely in ICU's however there is not a standardised evidence-based guideline to effectively guide phosphate administration for ICU patients

This is a cluster, crossover, electronic medical record integrated, randomised, controlled trial. Sites (not patients) will be randomised to wither the liberal or restrictive phosphate replacement protocol for a 6-month period, followed by a 1-month washout period, before switching to the next protocol for the preceding 6-month period. The allocated phosphate replacement protocol will be updated in the electronic medical record to be followed; this process is already part of normal clinical practice.

• Study Type: Interventional
• Enrollment (Estimated): 2400
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Mahesh Ramanan; Phone Number: +61 7 5433 8888; Email: mahesh.ramanan@health.qld.gov.au
• Study Contact Backup: Name: Emma L Williams; Phone Number: +61 488 474 254; Email: emma.williams6@health.qld.gov.au

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• All adult patients admitted to participating intensive care units during the study period.

Exclusion Criteria:

• There will be no specific exclusion criteria

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Liberal Phosphate Replacement Protocol; The liberal group, a recommendation for phosphate replacement would be given if the serum phosphate concentration was 0.79 mmol/L, but not if 0.80 mmol/L.	Other: Liberal Phosphate Replacement Protocol; The liberal group, a recommendation for phosphate replacement would be given if the serum phosphate concentration was 0.79 mmol/L, but not if 0.80 mmol/L.
Active Comparator: Conservative Phosphate Replacement Protocol; The restrictive protocol will recommend phosphate replacement to commence at a threshold of 0.50 mmol/L, and the liberal protocol at 0.80 mmol/L.	Other: Restrictive Phosphate Replacement Protocol; The restrictive protocol will recommend phosphate replacement to commence at a threshold of 0.50 mmol/L, and the liberal protocol at 0.80 mmol/L.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
non-inferiority for days alive and free of the intensive care unit (ICU) up to 30 days (DAF-ICU-30)	The primary outcome will be assessed as non-inferiority in the number of days alive and free of ICU within 30 days from study enrolment. ICU length of stay will be used to calculate. This measure is reported on a continuous scale ranging from 0 (worst outcome: death or full ICU stay) to 30 (best outcome: alive and ICU-free for all 30 days), where higher scores indicate a better outcome. The difference between groups will be expressed as a mean difference with 95% confidence intervals.	30 Days post study enrolment

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Phosphate usage	Quantities of intravenous and oral phosphate replaced (total and individually)	individual arm and total quantities used over 12-month study period
Patients receiving phosphate	Proportion of patients receiving any phosphate replacement	total proportion of patients receiving phosphate throughout 12-month study period
Hospital Length of Stay	Total time spent in hospital - hospital admission time to hospital discharge time	hospital admission to hospital discharge throughout 12-month study period
Hospital Mortality	hospital mortality rates for all participants throughout study period	hospital admission to hospital discharge throughout 12-month study period
cardiac rhythm disturbance	Symptomatic cardiac rhythm disturbance (cardiac arrhythmia that requires treatment with chemical or electric cardioversion)	ICU admission to ICU discharge, throughout 12-month study period
Mechanical ventilation hours	Hours of invasive mechanical ventilation	hospital admission to hospital discharge, throughout 12-month study period
Tracheal reintubation	Tracheal intubation requirement during admission	hospital admission to hospital discharge, throughout 12-month study period

Collaborators and Investigators

• Sponsor: Caboolture Hospital
• Collaborators: Queensland University of Technology
• Investigators: Principal Investigator: Mahesh Ramanan, +61 7 5433 8888

Publications and helpful links

General Publications

• Ramanan M, Tabah A, Affleck J, Edwards F, White KC, Attokaran A, Laupland K. Hypophosphataemia in Critical Illness: A Narrative Review. J Clin Med. 2024 Nov 26;13(23):7165. doi: 10.3390/jcm13237165.
• Sin JCK, Laupland KB, Ramanan M, Tabah A. Phosphate abnormalities and outcomes among admissions to the intensive care unit: A retrospective multicentre cohort study. J Crit Care. 2021 Aug;64:154-159. doi: 10.1016/j.jcrc.2021.03.012. Epub 2021 Apr 18.

Study record dates

Study Major Dates

• Study Start (Estimated): January 1, 2026
• Primary Completion (Estimated): February 1, 2027
• Study Completion (Estimated): December 1, 2027

Study Registration Dates

• First Submitted: November 20, 2025
• First Submitted That Met QC Criteria: December 4, 2025
• First Posted (Actual): December 17, 2025

Study Record Updates

• Last Update Posted (Actual): December 17, 2025
• Last Update Submitted That Met QC Criteria: December 4, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: Intensive Care; Critical Care; Hypophosphatemia; Phosphate Protocol; Phosphate Deficiency
• Additional Relevant MeSH Terms: Metabolic Diseases; Phosphorus Metabolism Disorders; Nutritional and Metabolic Diseases; Hypophosphatemia
• Other Study ID Numbers: HREC/2025/MNH/121108

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No