National trends in incidence rates of hospitalization for stroke in children with sickle cell disease

Abstract

Background: The success of primary stroke prevention for children with sickle cell disease (SCD) throughout the United States is unknown. Therefore, we aimed to generate national incidence rates of hospitalization for stroke in children with sickle cell disease (SCD) before and after publication of the Stroke Prevention Trial in Sickle Cell Anemia (STOP trial) in 1998.

Procedure: We performed a retrospective trend analysis of the 1993-2009 Nationwide Inpatient Sample and Kids' Inpatient Databases. Hospitalizations for SCD patients 0-18 years old with stroke were identified by ICD-9CM code. The primary outcome, the trend in annual incidence rate of hospitalization for stroke in children with SCD, was analyzed by linear regression. Incidence rates of hospitalization for stroke before and after 1998 were compared by the Wilcoxon rank-sum test.

Results: From 1993 to 2009, 2,024 hospitalizations were identified for stroke. Using the mean annual incidence rate of hospitalization for stroke from 1993 to 1998 as the baseline, the rate decreased from 1993 to 2009 (point estimate = -0.022/100 patient years [95% CI, -0.039, -0.005], P = 0.027). The mean annual incidence rate of hospitalization stroke decreased by 45% from 0.51 per 100 patient years in 1993-1998 to 0.28 per 100 patient years in 1999-2009 (P = 0.008). Total hospital days and charges attributed to stroke also decreased by 45% and 24%, respectively.

Conclusions: After publication of the STOP trial and hydroxyurea licensure in 1998, the incidence of hospitalization for stroke in children with SCD decreased across the United States, suggesting that primary stroke prevention has been effective nationwide, but opportunity for improvement remains.

Fig. 1

National trend in annual incidence rates of hospitalization for stroke in US children with sickle cell disease. Prior to STOP trial publication and hydroxyurea licensure (1993–1998), the mean annual incidence rate of hospitalization for stroke was 0.51 per 100 patient years. Following STOP trial publication and hydroxyurea licensure (1999–2009), the mean annual incidence rate of hospitalization for stroke decreased 45% to 0.28 per 100 patient years.

Fig. 2

National trend in annual cumulative hospital days for stroke in US children with sickle cell disease. The mean annual cumulative hospital days attributable to stroke decreased 45% from 1,330 days/year (95% CI, 974–1,685) from 1993 to 1998 to 732 days/year (95% C.I., 537–927) for 1999–2009.