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NCT Number: NCT07168447

Transfusion Exchanges and Cognition in Sickle Cell Disease

DREPA-COG is an observational study evaluating the effect of exchange transfusions on cognitive function in adults with severe sickle cell disease (SS or Sβ0). Information processing speed is assessed at three time points during the transfusion cycle using the Symbol Digit Modalities Test (SDMT) and additional validated neuropsychological measures. This minimal-risk, fully remote study aims to identify processing speed as a reproducible marker for clinical monitoring and future therapeutic trials.

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Key information

Conditions

Drepanocytosis Anemia Anemia, Hemolytic Anemia, Hemolytic, Congenital Anemia, Sickle Cell Anxiety Disorders Behavior Behavioral Symptoms Chronic Neurological Deficiency Congenital, Hereditary, and Neonatal Diseases and Abnormalities Depression Fatigue Genetic Diseases, Inborn Hematologic Diseases Hemic and Lymphatic Diseases Hemoglobinopathies Mental Disorders Pathological Conditions, Signs and Symptoms Sickle Cell Trait Signs and Symptoms

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

Assistance Publique - Hôpitaux de Paris Hôpital Avicenne, Bobigny, Île-de-France Region, France

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About this study

DREPA-COG is a non-interventional, multicenter observational study investigating the effect of exchange transfusions on cognitive performance in adults with severe sickle cell disease (SS or Sβ0). Cognitive complications, including slowed information processing and executive dysfunction, are frequent and disabling in this population. Exchange transfusion, a standard therapy replacing sickled red blood cells with donor cells, may positively influence cognition, but systematic evidence is lacking.

The study evaluates information processing speed as a potential neurological marker across the transfusion cycle. Participants complete three brief neuropsychological assessments remotely by videoconference: before the transfusion, one week after, and prior to the next transfusion. The Symbol Digit Modalities Test (SDMT) is the primary measure, complemented by validated assessments of global cognition, attention, memory, fatigue, mood, and pain.

Primary analysis will use mixed-effects models to assess changes in processing speed over time, adjusting for demographic and clinical covariates. This minimal-risk, fully remote study requires no additional hospital visits and aims to establish processing speed as a reproducible and clinically relevant outcome measure in sickle cell disease.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Adults (≥18 years) with severe sickle cell disease (SS or Sβ0).
  • Enrolled in a regular monthly transfusion exchange program.
  • Not institutionalized.
  • No known dementia.
  • No severe aphasia.
  • Affiliated with or beneficiary of a social security system.

Exclusion criteria

  • Insufficient mastery of spoken French.
  • Severe comorbidities preventing short-term follow-up.
  • Known psychiatric disorders.
  • Participation in another clinical study with ongoing exclusion periods.
  • Lack of adequate computer equipment (minimum 11-inch screen and internet connection).
  • Vulnerable patients under legal protection (guardianship or curatorship).

Treatment and study plan

Primary outcomes

  1. Information Processing Speed

    Time frame: 48 hours before the transfusion exchange

    Primary outcome measure: Information processing speed, assessed using the oral version of the Symbol Digit Modality Test (SDMT), as a marker of cerebral involvement in adult patients with sickle cell disease.

  2. Information Processing Speed

    Time frame: 7 to 9 days after the transfusion exchange

    Primary outcome measure: Information processing speed, assessed using the oral version of the Symbol Digit Modality Test (SDMT), as a marker of cerebral involvement in adult patients with sickle cell disease.

  3. Information Processing Speed

    Time frame: within 48 hours before the next scheduled transfusion exchange

    Primary outcome measure: Information processing speed, assessed using the oral version of the Symbol Digit Modality Test (SDMT), as a marker of cerebral involvement in adult patients with sickle cell disease.

Secondary outcomes

  1. Global Cognitive Function - Montreal Cognitive Assessment (Telephone version, T-MoCA)

    Time frame: Time Point 1 (Baseline): within 48 hours before the scheduled exchange transfusion. Time Point 2 (Post-transfusion): 7 to 9 days after the exchange transfusion. Time Point 3 (End of cycle): within 48 hours before the next scheduled exchange transfusion

    The T-MoCA is a validated screening tool for global cognition, adapted for telephone administration. Scores range from 0 to 22, with higher scores indicating better cognitive performance.

  2. Fatigue Severity Score (FSS)

    Time frame: Time Point 1 (Baseline): within 48 hours before the scheduled exchange transfusion. Time Point 2 (Post-transfusion): 7 to 9 days after the exchange transfusion. Time Point 3 (End of cycle): within 48 hours before the next scheduled exchange transfusion

    Fatigue will be assessed using the Fatigue Severity Scale (FSS), a validated self-administered questionnaire consisting of 9 items, each rated on a 7-point Likert scale (1 = strongly disagree; 7 = strongly agree).

    The total score is the mean of the 9 items, ranging from 1 (no fatigue) to 7 (severe fatigue).

    Higher scores indicate more severe fatigue and represent a worse outcome.

  3. Anxiety and Depression Symptoms (Hospital Anxiety and Depression Scale, HADS

    Time frame: Time Point 1 (Baseline): within 48 hours before the scheduled exchange transfusion. Time Point 2 (Post-transfusion): 7 to 9 days after the exchange transfusion. Time Point 3 (End of cycle): within 48 hours before the next scheduled exchange transfusion

    The Hospital Anxiety and Depression Scale (HADS) is a validated self-report questionnaire consisting of 14 items, divided into two subscales: Anxiety (HADS-A, 7 items) and Depression (HADS-D, 7 items). Each subscale score ranges from 0 to 21, with higher scores indicating more severe symptoms.

  4. Pain Intensity (Numeric Rating Scale, NRS)

    Time frame: Time Point 1 (Baseline): within 48 hours before the scheduled exchange transfusion. Time Point 2 (Post-transfusion): 7 to 9 days after the exchange transfusion. Time Point 3 (End of cycle): within 48 hours before the next scheduled exchange transfusion

    Pain intensity will be assessed using the Numeric Rating Scale (NRS), a validated self-report tool where participants rate their pain on a scale from 0 to 10.

    0 = no pain

    10 = worst imaginable pain Higher scores indicate greater pain intensity.

  5. Change in Information Processing Speed Measured by the Symbol Digit Modalities Test (SDMT)

    Time frame: Within 48 hours before exchange transfusion 7-9 days after exchange transfusion Within 48 hours before the next scheduled exchange transfusion

    Information processing speed will be assessed using the Symbol Digit Modalities Test (SDMT), a standardized neuropsychological test that evaluates attention, visual scanning, and motor speed. The test provides a raw score, which reflects the number of correct pairings completed within a 90-second period.

    Higher scores indicate better information processing speed.

    This measure aims to evaluate changes in SDMT scores across the transfusion cycle and identify individual variability in performance.

  6. Working Memory - WAIS-IV Digit Span Subtest

    Time frame: Time Point 1 (Baseline): within 48 hours before the scheduled exchange transfusion. Time Point 2 (Post-transfusion): 7 to 9 days after the exchange transfusion. Time Point 3 (End of cycle): within 48 hours before the next scheduled exchange transfusion

    The Digit Span subtest from the Wechsler Adult Intelligence Scale, Fourth Edition (WAIS-IV), assesses working memory capacity. Scores range from 0 to 16, with higher scores reflecting better performance.

Study contacts

Contact information is provided by the study sponsor or research team.

Khaoussou SYLLA, MEDICAL COORDINATOR

CONTACT

[email protected]

01 45 65 76 78 ext. +33

OUIZA MANSEUR, PROJECT MANAGER

CONTACT

[email protected]

01 45 65 84 86 ext. +33

Sponsors and collaborators

Lead sponsor

Centre Hospitalier St Anne

Other

Registry information

Official study title

Effect of Exchange Transfusions on Cognitive Efficiency in Patients With Sickle Cell Disease

Acronym: DREPA-COG

Important dates

Study start
2025
Primary completion
2027
Study completion
2027
First posted
Sep 11, 2025
Registry last updated
Sep 11, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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