Low-risk factors for severe bacterial infection and acute chest syndrome in children with sickle cell disease.

INTRODUCTION: The rate of bacterial infections in children with sickle cell disease (SCD) has decreased in recent years, mainly due to penicillin prophylaxis and vaccination.

OBJECTIVES: To determine the rate of severe bacterial infection (SBI) in a cohort of children with SCD and to describe low-risk factors for confirmed SBI (CSBI) and acute chest syndrome (ACS).

METHODS: This 11-year retrospective cohort study included children with febrile SCD admitted to a reference hospital in Spain. A case-control study was performed comparing patients diagnosed with SBI to those without SBI, and subanalyses for groups with CSBI and ACS were carried out.

RESULTS: A total of 316 febrile episodes were analyzed; 69 (21.8%) had confirmed or possible SBI. Thirteen of those had CSBI (4.1%), eight urinary tract infection, and five bacteremia/sepsis. Among the cases of possible SBI, the majority had ACS (54/56; 96.4%). Age >3 years, absence of central venous catheter, hemodynamic stability, and procalcitonin <0.6 ng/ml were low-risk factors for CSBI, whereas normal oxygen saturation and C-reactive protein <3 mg/dl were low-risk factors for ACS, with negative predictive values (NPV) of 98.3%, 97.4%, 96%, 97.2%, 87.5%, and 85.8%, respectively.

CONCLUSION: In this cohort of children with SCD who were well vaccinated and received adequate prophylaxis, we found a low rate of bacteremia and CSBI. We described several low-risk factors for CSBI and ACS, all of them with a high NPV. These findings may help to develop a risk score to safely select the patients that could be managed with a more conservative approach.