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.