Sickle cell anaemia anemia: blood transfusions decreased stroke.

Clinical bottom line (level 1b)

  1. Children with sickle cell anaemia who were given blood transfusions were less likely to have a stroke than those given standard care (NNT = 7 at 2 years) .
Adams et al: New England Journal of Medicine 1998; 339 (1): 5-11
Expires January 2003

The study

?blinded ?concealed randomised trial ?with intention-to-treat
Setting: USA

130 patients (aged mean 8 years, 60% male) children with sickle cell anaemia or sickle beta-thalassemia and had undergone two transcranial Doppler studies

Excluded if
  • aged <2 or >16 years
  • history of stroke
  • indication for or contraindication to long-term transfusion
  • receiving other treatments that affect the risk of stroke
  • infected with HIV
  • had been treated for seizures
  • pregnant
  • serum ferritin concentration above 500 ng/ml


    • Note:
  • Baseline haemoglobin and haematocrit values were slightly lower in the transfusion group.


    • Control Group: (n = 67, 67 analysed): standard care
    Experimental Group: (n = 63, 62 analysed): Blood transfusions to reach target haemoglobin S concentration (<30% of total haemoglobin) within 21 days without exceeding a haemoglobin concentration of 12 g/dL and a haematocrit of 36%, measured before transfusion. Transfusions were given every three to four weeks when the haemoglobin S concentration was 30% the total haemoglobin.
    Concomitant care included penicillin prophylaxis, pneumococcal vaccination, folic acid supplementation, surgery and treatment of acute illness, including the use of transfusion when needed for transient episodes but excluding the use of hydroxyurea or antisickling agents.
    99% followed for 2 years
    Outcome notes:
    • stroke : cerebral infarction or intracerebral haematoma

    The evidence

    Outcome Time to outcome CEREERRRR
    (95% CI)    		ARR
    (95% CI)    		NNT
    (95% CI)
    stroke 2 years 11
    (16.4%)    		 1
    (1.59%)    		 90.0%
    (27.0% to 99.0%)    		 14.8%
    (5.44% to 24.2%)    		 7
    (4 to 18)

    Comments

    1. There is as yet no good evidence to indicate how often to perform transcranial dopplers nor whether the programme would be cost-effective.
    2. Ten patients dropped out of the transfusion group, but only one was lost to follow-up.
    3. Two patients crossed over from standard care to transfusions.

    Citation

    1. Adams RJ, McKie VC, Hsu L, et al: Prevention of a first stroke by transfusions in children with sickle cell anemia and abnormal results on transcranial Doppler ultrasonography. New England Journal of Medicine 1998; 339 (1): 5-11
    Contributor: Clare Wotton and Musab Hayatli, January 2000
    Reviewer: Mona Nabulsi

    Clinical Question.
    Patient children with sickle cell anaemia
    Intervention or Exposure blood transfusions
    Comparison standard care
    Outcome stroke