Utilization of TCD screening for primary stroke prevention in children with sickle cell disease.
BACKGROUND
In 1998, the Stroke Prevention Trial in Sickle Cell Anemia showed a >90% reduction in stroke rates after blood transfusion therapy in children with sickle cell disease (SCD) identified as high risk with transcranial Doppler ultrasonography (TCD) screening.


METHODS
We studied the utilization of TCD screening in a retrospective cohort of all children with SCD within a large managed care plan from January 1993 to December 2005. Rates of first TCD screening were estimated using life table methods; predictors of TCD were evaluated using Cox proportional hazards regression. Stroke incidence rates were estimated in person-time before (pre-TCD) and after (post-TCD) first TCD.


RESULTS
The average annual rate of TCD screening in 157 children with SCD was 1.8 per 100 person-years pre-1998, 5.0 from January 1, 1998, to December 31, 1999, and 11.4 after 1999. The only independent predictor of TCD screening was proximity to the vascular laboratory. The annualized stroke rate pre-TCD was 0.44 per 100 person-years, compared to 0.19 post-TCD.


CONCLUSIONS
Since the Stroke Prevention Trial in Sickle Cell Anemia, the rate of transcranial Doppler ultrasonography (TCD) screening in sickle cell disease (SCD) has increased sixfold within a large health care plan. Children living farther from a vascular laboratory are less likely to be screened. Increased availability of TCD screening could improve the utilization of this effective primary stroke prevention strategy.
Armstrong-Wells
J
J
University of California, San Francisco, Department of Neurology, Box 0114, 505 Parnassus Avenue, San Francisco, CA 94143-0114, USA.
Grimes
B
B
Sidney
S
S
Kronish
D
D
Shiboski
S C
SC
Adams
R J
RJ
Fullerton
H J
HJ
D000293:Adolescent; D000755:Anemia, Sickle Cell / Q000150:complications* / Q000000981:diagnostic imaging*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012044:Regression Analysis; D012189:Retrospective Studies; D020521:Stroke / Q000000981:diagnostic imaging* / Q000453:epidemiology* / Q000209:etiology; D065227:Transfusion Reaction; D017585:Ultrasonography, Doppler, Transcranial