Epidemiology of Silent and Overt Strokes in Sickle Cell Disease (ESCD)

February 10, 2026 updated by: Michael DeBaun, Vanderbilt University Medical Center

The Epidemiology of Silent and Overt Strokes in Adults With Sickle Cell Disease: a Prospective Cohort Study

Sickle Cell Disease (SCD) is a rare disease occurring in an estimated 100,000 individuals, often poor and underserved, in the US. Silent and overt strokes contribute significantly to morbidity in adults with SCD, resulting in functional impairment, challenges with school and job performance, and premature death. Five NIH-funded randomized controlled trials have identified therapies to prevent silent and overt strokes in children with SCD, including monthly blood transfusion therapy (for preventing initial and recurrent strokes) and hydroxyurea (for preventing initial strokes). Despite the observation that at least 99% of children with SCD in high-income countries reach adulthood, and approximately 60% of adults will experience one or more strokes (~50% with silent strokes and ~10% with overt strokes), no stroke trials have established therapeutic approaches for adults with SCD. For adults with SCD, inadequate evidence-based guidelines exist for secondary stroke prevention strategies. Applying stroke prevention strategies in children may not be effective for stroke prevention in adults with SCD, particularly given the high rate of co-morbidities. Identifying subgroups of adults with SCD and higher incidence coupled with the contribution of established stroke risk factors in the general population (smoking, diabetes, obesity, renal disease) will provide the requisite data required for the first-ever phase III clinical trials focused on secondary stroke prevention in adults.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Active, not recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Detailed Description

In three adult SCD centers, we will conduct a prospective cohort study to test the primary hypothesis that the incidence of infarct recurrence (stroke or silent stroke) or new strokes in adults with silent strokes treated with hydroxyurea will be greater than in those without strokes treated with hydroxyurea. We will test two secondary hypotheses: 1) adults with SCD and silent strokes have cognitive morbidity when compared to adults with SCD without silent strokes, and 2) adults with SCD and strokes receiving regular blood transfusion will have a higher incidence of infarct recurrence than those with SCD without strokes. The aims include Aim 1: Compare the incidence of new overt and silent strokes in adults with SCD and silent strokes to a comparison group of adults without silent strokes or overt strokes. Aim 2: Compare the cognitive morbidity of those with silent strokes and overt strokes to those without strokes. Aim 3: Compare the incidence of new overt and silent stroke in adults with SCD and overt strokes receiving transfusion to adults with SCD without silent or overt strokes treated with hydroxyurea. All clinical information and neuroimaging will be centrally adjudicated with masked and experienced neurology and neuroradiology committees. Data generated after completion of this proposal are critical for developing the first-ever phase III trials for secondary stroke prevention therapies in adults with SCD.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
102

Contacts and Locations

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

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

  • United States
    • Alabama
      • Birmingham, Alabama, United States, 35233
        • University of Alabama at Birmingham
    • Missouri
      • St Louis, Missouri, United States, 63110
        • Washington University School of Medicine
    • Tennessee
      • Nashville, Tennessee, United States, 37232
        • Vanderbilt University Medical Center
      • Nashville, Tennessee, United States, 37232-9000
        • Vanderbilt University Medical Center

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Participants will be patient volunteers from the sickle cell disease clinics of participating study sites.

Description

Inclusion Criteria:

  1. Participants with sickle cell disease on hemoglobin analysis and/or other confirmatory documentation of phenotype
  2. Patients ≥ 18 years of age
  3. Patients followed regularly (at least two visits per year) in the hematology clinics
  4. Patients who have demonstrated adherence with follow-up visits for ≥ 3 years
  5. Patients willing to be followed prospectively for a minimum of 3.5 years and agree to a standard care exit MRI/MRA of the brain, as well as MRI/MRA every 12 to 18 months or participation in VUMC AHA trial with Dr. Jordan as PI. These are adults with SCA aged 18-40 years at study entry, enrolled with any infarct status (none, SCI or overt stroke) and followed prospectively.
  6. Willingness to comply with study protocol, routine clinic visits

Exclusion criteria:

  1. Participants judged to be non-compliant by the hematologist based on previous experience in terms of clinic appointments and following advice
  2. Participants with contraindications to MRI, including individuals with MRI-incompatible foreign metal objects

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

  • Observational Models: Cohort
  • Time Perspectives: Prospective

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
SCA with overt stroke
Participants have sickle cell disease and a history of overt stroke.
SCA with silent stroke
Participants have sickle cell disease and a history of silent stroke.
SCA with no stroke
Participants have sickle cell disease and no history of stroke.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Adjudication of silent stroke in those with reported history of silent stroke and hydroxyurea therapy
Time Frame: Study enrollment
Based on results of an MRI exam and a neurological exam, performed by a physician, the Neuroradiology Committee and the Neurology Committee will come to consensus on whether a silent stroke has occurred. Radiologically, silent stroke will be defined as a FLAIR T2W hyperintensity greater than 3 mm, visible in two planes. Neurologically, a silent stroke has no neurological sequelae.
Study enrollment
Adjudication of new strokes in those with history of silent stroke and on hydroxyurea therapy
Time Frame: Every 12 to 18 months after enrollment
Based on results of an MRI exam and a neurological exam, performed by a physician, the Neuroradiology Committee and the Neurology Committee will come to consensus on whether a NEW stroke has occurred since the last exams, and if so, whether it is a silent stroke or overt stroke. Radiologically, silent stroke will be defined as a FLAIR T2W hyperintensity greater than 3 mm, visible in two planes. Neurologically, a silent stroke has no neurological sequelae.
Every 12 to 18 months after enrollment
Adjudication of new strokes in those with history of silent stroke and on hydroxyurea therapy
Time Frame: At study exit (at least 3.5 years after enrollment)
Based on results of an MRI exam and a neurological exam, performed by a physician, the Neuroradiology Committee and the Neurology Committee will come to consensus on whether a NEW stroke has occurred since the last exams, and if so, whether it is a silent stroke or overt stroke. Radiologically, silent stroke will be defined as a FLAIR T2W hyperintensity greater than 3 mm, visible in two planes. Neurologically, a silent stroke has no neurological sequelae.
At study exit (at least 3.5 years after enrollment)

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Cognitive morbidity in those with silent or overt stroke
Time Frame: Study enrollment
All participants will complete the NIH Toolbox CB. The NIH Toolbox CB allows for the evaluation of several cognitive constructs and yields individual measure scores as well as a composite score. This measure will serve as a baseline for all participants.
Study enrollment
Cognitive morbidity in those with silent or overt stroke
Time Frame: Every 12 to 18 months after enrollment
Participants will complete the NIH Toolbox CB. The NIH Toolbox CB allows for the evaluation of several cognitive constructs and yields individual measure scores as well as a composite score. Results will be compared to the previous measurement(s) to determine if change has occurred.
Every 12 to 18 months after enrollment
Cognitive morbidity in those with silent or overt stroke
Time Frame: At study exit (at least 3.5 years after enrollment)
Participants will complete the NIH Toolbox CB. The NIH Toolbox CB allows for the evaluation of several cognitive constructs and yields individual measure scores as well as a composite score. Results will be compared to the previous measurement(s) to determine if change has occurred.
At study exit (at least 3.5 years after enrollment)
Adjudication of overt stroke in those with reported history of overt stroke and on transfusion therapy
Time Frame: Study enrollment
Based on results of an MRI exam and a neurological exam, performed by a physician, the Neuroradiology Committee and the Neurology Committee will come to consensus on whether an overt stroke has occurred.
Study enrollment
Adjudication of new strokes in those with history of overt stroke and on transfusion therapy
Time Frame: Every 12 to 18 months after enrollment
Based on results of an MRI exam and a neurological exam, performed by a physician, the Neuroradiology Committee and the Neurology Committee will come to consensus on whether a NEW stroke has occurred since the last exams, and if so, whether it is a silent stroke or overt stroke. Radiologically, silent stroke will be defined as a FLAIR T2W hyperintensity greater than 3 mm, visible in two planes. Neurologically, a silent stroke has no neurological sequelae.
Every 12 to 18 months after enrollment
Adjudication of new strokes in those with history of overt stroke and on transfusion therapy
Time Frame: At study exit (at least 3.5 years after enrollment)
Based on results of an MRI exam and a neurological exam, performed by a physician, the Neuroradiology Committee and the Neurology Committee will come to consensus on whether a NEW stroke has occurred since the last exams, and if so, whether it is a silent stroke or overt stroke. Radiologically, silent stroke will be defined as a FLAIR T2W hyperintensity greater than 3 mm, visible in two planes. Neurologically, a silent stroke has no neurological sequelae.
At study exit (at least 3.5 years after enrollment)

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Vanderbilt University Medical Center

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Washington University School of Medicine
University of Alabama at Birmingham

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Michael R DeBaun, MD, MPH, Vanderbilt University Medical Center
  • Principal Investigator: Lori C. Jordan, PhD, MD, Vanderbilt University Medical Center

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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
June 2, 2017

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 31, 2025

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 31, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
December 8, 2017

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
December 12, 2017

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
December 19, 2017

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
February 13, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 10, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
February 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 161434

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

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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