Hospitalization for invasive pneumococcal disease in a national sample of children with sickle cell disease before and after PCV7 licensure

Objective: To estimate national hospitalization rates for invasive pneumococcal disease (IPD) in children with sickle cell disease (SCD) before and after the 2000 licensure of the heptavalent pneumococcal conjugate vaccine (PCV7). Procedure: We performed a retrospective trend analysis of the 1994-2007 Nationwide Inpatient Sample databases. Hospitalizations involving children with SCD and IPD were identified by ICD-9CM code. The primary outcomes, the annual hospitalization rate for IPD in children with SCD and the proportion of hospitalizations for IPD per 100 total SCD hospitalizations, were analyzed using multivariable linear regression and contingency analysis, respectively. Results: A total of 1,242 hospitalizations for IPD in SCD patients were identified from 1994-2007, with a mortality rate of 2.4%. The national mean annual rate of IPD hospitalization decreased by 65%, from 131.8cases/year from 1994 to 2000 to 45.5cases/year from 2001 to 2007 (P=0.001). The national proportion of hospitalizations for IPD per 100 total SCD hospitalizations decreased from 0.4 to 0.15 (P<0.0001) over the same interval. Following PCV7 licensure, the mean annual cumulative hospital days and cumulative hospital charges decreased nationally by 53% and 36%, respectively. Conclusion: In a national sample, PCV7 licensure is temporally associated with a nearly threefold reduction in IPD hospitalizations in children with SCD.