Cost modelling incorporating procalcitonin for the risk stratification of febrile infants ≤60 days old.

Objectives: Procalcitonin testing is recommended to discriminate febrile young infants at risk of serious bacterial infections (SBI). However, this test is not available in many clinical settings, limited largely by cost. This study sought to evaluate contemporary real-world costs associated with the usual care of febrile young infants, and estimate impact on clinical trajectory and costs when incorporating procalcitonin testing. Methods: We assessed hospital-level door-to-discharge costs of all well-appearing febrile infants aged ≤60 days, evaluated at a tertiary paediatric hospital between April/2016 and March/2019. Emergency Department and inpatient expense data for usual care were obtained from the institutional general ledger, validated by the provincial Ministry of Health. These costs were then incorporated into a probabilistic model of risk stratification for an equivalent simulated cohort, with the addition of procalcitonin. Results: During the 3-year study period, 1168 index visits were included for analysis. Real-world median costs-per-infant were the following: $3266 (IQR $2468 to $4317, n=93) for hospitalized infants with SBIs; $2476 (IQR $1974 to $3236, n=530) for hospitalized infants without SBIs; $323 (IQR $286 to $393, n=538) for discharged infants without SBIs; and, $3879 (IQR $3263 to $5297, n=7) for discharged infants subsequently hospitalized for missed SBIs. Overall median cost-per-infant of usual care was $1555 (IQR $1244 to $2025), compared to a modelled cost of $1389 (IQR $1118 to $1797) with the addition of procalcitonin (10.7% overall cost savings; $1,816,733 versus $1,622,483). Under pessimistic and optimistic model assumptions, savings were 5.9% and 14.9%, respectively. Conclusions: Usual care of febrile young infants is variable and resource intensive. Increased access to procalcitonin testing could improve risk stratification at lower overall costs.