An observational study in Drepanocytosis and Chronic Neurological Deficiency, sponsored by Centre Hospitalier St Anne. Not yet recruiting at 6 sites in France. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2025-09-11.
Sponsored by Centre Hospitalier St Anne · Observational
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.
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.
43 studies on the registry are indexed under Sickle Cell Trait; 11 are open to participants now.
This study's planned enrollment of 85 is below the median of 109 across 20 observational studies indexed under Sickle Cell Trait.
Browse Sickle Cell Trait studies →Centre Hospitalier St Anne is the lead sponsor of 101 studies on the registry; 55 are open to participants now.
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The study population consists of adults aged 18 years or older with severe sickle cell disease (SS or Sβ0) who are enrolled in a regular monthly transfusion exchange program. Participants must not be institutionalized, must have no known dementia or severe aphasia, and must be able to communicate in French. They must also be affiliated with a social security system. Excluded are individuals with severe comorbidities that could interfere with short-term follow-up, those with known psychiatric disorders, participants in other ongoing clinical studies with exclusion periods, individuals lacking adequate computer equipment for remote assessments, and vulnerable patients under legal protection such as guardianship or curatorship. This population allows evaluation of cognitive processing speed and other neuropsychological outcomes in a controlled, transfusion-managed cohort of adult sickle cell patients.
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Exclusion criteria:
Information Processing Speed
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.
Time frame: 48 hours before the transfusion exchange
Information Processing Speed
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.
Time frame: 7 to 9 days after the transfusion exchange
Information Processing Speed
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.
Time frame: within 48 hours before the next scheduled transfusion exchange
Global Cognitive Function - Montreal Cognitive Assessment (Telephone version, T-MoCA)
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.
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 Severity Score (FSS)
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.
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
Anxiety and Depression Symptoms (Hospital Anxiety and Depression Scale, HADS
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.
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 (Numeric Rating Scale, NRS)
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.
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
Change in Information Processing Speed Measured by the Symbol Digit Modalities Test (SDMT)
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.
Time frame: Within 48 hours before exchange transfusion 7-9 days after exchange transfusion Within 48 hours before the next scheduled exchange transfusion
Working Memory - WAIS-IV Digit Span Subtest
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.
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
Plan to share: Undecided
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