Epidemiology of Thrombotic Thrombocytopenia Syndrome in Integrated Health-care Database in England

December 5, 2023 updated by: AstraZeneca

Epidemiology of Thrombotic Thrombocytopenia Syndrome in Integrated Health-care Database in England.Secondary Data Analysis Using a Cohort Design

Background/Rationale: A rare syndrome of thrombosis associated with low platelets has been reported in a few cases of recent exposure to COVID-19 vaccine. Medicines & Healthcare products Regulatory Agency (MHRA) had requested for all cases of thrombosis or thrombocytopenia occurring within 28 days of coronavirus vaccine to be reported via the online yellow card system. This syndrome seems to be affecting patients of all ages and both genders; at present there is no clear signal of risk factors. Up to and including 14 April 2021, the MHRA had received 168 United Kingdom (UK) reports of thrombo-embolic events with concurrent low levels of platelets following the use of the COVID-19 Vaccine AstraZeneca. The United Kingdom (UK) is uniquely placed to study this area because of its registration-based primary care system, and a unique identifier number links primary care to secondary care data. Additionally, vaccination is well advanced, maximising population wide vaccine exposure.

Objectives and Hypotheses: Estimate event rates and describe characteristics of patients with a record for thrombotic thrombocytopenia syndrome, thromboembolism or thrombocytopenia, in the general population of England.

Methods:

Study design: Secondary data analysis using a cohort design. Data Source(s): This is a retrospective cohort study using linked secondary databases in England accessed through the NHS Digital Trusted Research Environment (TRE). The primary care data will be linked with vaccination, primary care data, hospitalization, COVID-19 test results, mortality data at the national level for capture of key study variables. This integrated digital health system will also include other linkages such as the Oxford-Royal College of General Practitioners sentinel network; ORCHID.

Study Population: All patients, with our population of interest in England who are present in the integrated health records of NHS Digital TRE and/or the Oxford Royal College of General Practitioners Clinical Informatics Digital Hub (ORCHID) database at the start of each study period.

Variables: Demographic, socioeconomic, clinical descriptors and risk factors for thrombosis and/or thrombocytopenia; COVID-19 vaccines.

Statistical Analysis: The event rates with 95% CIs will be calculated by dividing the number of events with person-time at risk per 100,000 person-years. Further, event count and event rates will be evaluated in a relationship with COVID-19 vaccination date.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Observational

Enrollment (Actual)

41200246

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child
  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

All patients, with a primary focus from age 16 years old and older, in England who are present in the integrated database at the start of each study period.

Description

Inclusion Criteria:

  • All patients, with a primary focus from age 16 years old and older, in England who are present in the integrated database at the start of each study period.

Exclusion Criteria:

  • Less than 12 months of prior history at start of each respective study period.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
COVID-19
Other: COVID-19
COVID-19
Pre-COVID-19
Other: Pre-COVID-19
Pre-COVID-19
COVID-19 vaccination roll - out
Other: COVID-19 vaccination roll-out
COVID-19 vaccination roll-out

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Estimate event rates and describe characteristics of patients with a record for thrombotic thrombocytopenia syndrome, thromboembolism or thrombocytopenia, in the general population of England.
Time Frame: 9 months
This is to complete studies in NHS Digital and ORCHID data
9 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

AstraZeneca

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

March 1, 2022

Primary Completion (Actual)

May 25, 2023

Study Completion (Actual)

May 25, 2023

Study Registration Dates

First Submitted

January 24, 2022

First Submitted That Met QC Criteria

January 24, 2022

First Posted (Actual)

February 3, 2022

Study Record Updates

Last Update Posted (Estimated)

December 11, 2023

Last Update Submitted That Met QC Criteria

December 5, 2023

Last Verified

November 1, 2023

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • D8111R00011

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Qualified researchers can request access to anonymized individual patient-level data from AstraZeneca group of companies sponsored clinical trials via the request portal.

All request will be evaluated as per the AZ disclosure commitment:

https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure.

Yes, indicates that AZ are accepting requests for IPD, but this does not mean all requests will be shared.

IPD Sharing Time Frame

AstraZeneca will meet or exceed data availability as per the commitments made to the EFPIA Pharma Data Sharing Principles. For details of our timelines, please rerefer to our disclosure commitment at

https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure.

IPD Sharing Access Criteria

When a request has been approved AstraZeneca will provide access to the deidentified individual patient-level data in an approved sponsored tool . Signed Data Sharing Agreement (non-negotiable contract for data accessors) must be in place before accessing requested information. Additionally, all users will need to accept the terms and conditions of the SAS MSE to gain access. For additional details, please review the Disclosure Statements at

https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure.

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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