Study design, data, and patients

We performed a retrospective cohort study using administrative data obtained from the Pennsylvania Healthcare Cost Containment Council (PHC4) from 2011-2014. PHC4 is an independent state agency that collects information on all inpatient hospital discharges from Pennsylvania hospitals. Each record contains de-identified data from the administrative claim, including patient demographics, dates of service, and International Classification of Diseases, 9^th revision, Clinical Modification (ICD-9-CM) diagnosis and procedure codes. We identified patient encounters for all patients aged 0 to 19 with ICD-9-CM codes consistent with sepsis, using both the “explicit”’ diagnosis codes for severe sepsis (995.92) and septic shock (785.52) and the “implicit” coding framework based on validated codes for infection and organ dysfunction (3, 21). This approach was chosen because it identifies clinical sepsis with the best mix of sensitivity and specificity compared to other administrative methods (22). Although these codes are limited in terms of their ability to accurately identify sepsis, clinical case ascertainment is not yet feasible at the state level and we considered these codes to be sufficiently accurate for making comparisons across hospitals.

We included only patients admitted to general acute care hospitals, excluding skilled nursing facility and long-term acute care hospital admissions as well as primary maternity hospitals. We defined primary maternity hospitals as hospitals with more than 70% of pediatric admissions stemming from a live birth. We also excluded hospitals with less than ten pediatric sepsis cases per year in order to reduce random variation from small sample sizes. In the event of multiple claims of sepsis per patient, we randomly selected one episode in order to prevent interdependence of observations.