Model-based Versus Traditional Warfarin Dosing in Children (WATCH)

A Study to Compare Model-based Warfarin Dosing to the Traditional Approach in Children After Congenital Heart Surgery at Glenfield Hospital, Leicester

This study compares the clinical effectiveness of a new algorithm (model-based warfarin dosing) with standard practice (doctor's own judgement and intuition) designed to determine the most appropriate anticoagulant dose of warfarin in children after congenital heart surgery.

Study Overview

• Status: Unknown
• Conditions: Congenital Heart Defects
• Intervention / Treatment: Device: Warfarin Dosing Aid; Other: Standard Practice

Detailed Description

Warfarin is widely used in children after heart surgery in order to prevent complications that may arise due to blood clots forming in unwanted places - for example in the brain causing a stroke. If too little warfarin is given, there is a risk that clots may form. If the dose is too high, bleeding will result.

Traditionally, the approach to dosing warfarin in children has been to select a starting dose according to standard guidelines and to then adjust the doses for each child by monitoring the INR (which measures how quickly blood clots). However, a person's make up as well as external factors, such as age, weight, diet and genetics can affect warfarin dosing and this makes controlling the dose and hence controlling the INR, more difficult. Recently however, a more sophisticated dosing model has been developed by researchers which takes into account some of these factors. The model is designed to help doctors select the best dose of warfarin for children by individualising prescriptions.

The aim of the proposed research is, therefore, to compare the model based warfarin dosing with the traditional approach to warfarin dosing in children who have undergone congenital heart surgery. The research will involve children who are started on warfarin for the first time and also children who are already receiving ongoing warfarin therapy.

• Study Type: Interventional
• Enrollment (Anticipated): 45
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Hussain Mulla, PhD; Phone Number: 0116 2563323; Email: hussain.mulla@uhl-tr.nhs.uk
• Study Contact Backup: Name: Peter Rivers, PhD; Phone Number: 7039 0116 2577039; Email: privers@dmu.ac.uk

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 1 day to 18 years (Child, Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria: -Children from birth up to 18 years with congenital heart disease who have been treated or to be treated with warfarin after undergoing reconstructive heart surgery at Glenfield Hospital, Leicester, United Kingdom.

Exclusion Criteria:

1. Patients aged over 18 years who are treated as 'adults'.
2. Children who refuse assent, parents who refuse consent.
3. Any significant disease or disorder which, in the opinion of the direct care team, may either put the participant at risk because of study participation or adversely affect the participants' ability to participate in the study.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Warfarin dosing aid; A pharmacokinetic/pharmacodynamic model-based dosing algorithm for warfarin.	Device: Warfarin Dosing Aid; A pharmacokinetic/pharmacodynamic model-based dosing algorithm for warfarin
Active Comparator: Standard practice; Dosing adjustments according to the normal unit protocol	Other: Standard Practice; Warfarin dose adjustments according to standard unit protocol

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The difference between the model based and traditional warfarin dosing method in International Normalised Ratio (INR) response.	INR response includes: Time taken (days per patient) to achieve stable anticoagulation within the desired therapeutic range (TR), number and percentage of INR measurements within the TR, Time in TR, and frequency of INR measurements (number of INR measurements per month) per patient.	6 months for warfarin naiive patients and 12 months for patients already on warfarin therapy.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Medical staff perceptions of value of warfarin dosing aid	Interviews with medical staff will be conducted	Within six months of end of period of data collection
Patients or carers 'lived experience' of monitoring warfarin dosing and INR	Interviews will be conducted with patients and or carers	Within six months of end of cross-over trial
The incidence of warfarin-related adverse events, bleeding and bruising, by recording on symptom diary cards		6 months for warfarin naiive patients and 12 months for patients already on warfarin therapy.

Collaborators and Investigators

• Sponsor: De Montfort University
• Collaborators: University Hospitals, Leicester
• Investigators: Principal Investigator: Hussain Mulla, PhD, Univesity Hospitals Leicester NHS Trust

Study record dates

Study Major Dates

• Study Start: August 1, 2015
• Primary Completion (Anticipated): August 1, 2016
• Study Completion (Anticipated): January 1, 2018

Study Registration Dates

• First Submitted: June 12, 2015
• First Submitted That Met QC Criteria: June 18, 2015
• First Posted (Estimate): June 19, 2015

Study Record Updates

• Last Update Posted (Estimate): June 22, 2015
• Last Update Submitted That Met QC Criteria: June 19, 2015
• Last Verified: June 1, 2015

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Heart Diseases; Cardiovascular Diseases; Congenital Abnormalities; Cardiovascular Abnormalities; Heart Defects, Congenital; Anticoagulants; Warfarin
• Other Study ID Numbers: DMU-1527