O0497 Oct.4: 6:18pm - Risk-stratification of infant fever: A cost-effectiveness analysis

Background: Approximately 200,000 infants ≤90 days of age present to emergency departments (ED) with fever every year. Among those <60 days old, serious bacterial infections (SBI), including meningitis, bacteremia and urinary tract infection (UTI), occur in 8-13%. Balancing the costs of medical evaluation and treatment, particularly unnecessary hospitalization, with the risks of misdiagnosis poses a clinical challenge. The cost-effectiveness of published clinical prediction rules in this population is unknown.

Objective: To evaluate the cost-effectiveness of strategies to identify infants with SBI in the ED using decision modeling.
Design/

Methods: We constructed a Markov decision model to evaluate outcomes in well-appearing, term febrile infants, using 7 strategies: Boston, Rochester, Philadelphia, Yale Observation Score, Pediatric Emergency Care Applied Research Network (PECARN), Step-by-Step, and Aronson. Infants in the simulated population were initially categorized as low-risk or not according to the above decision rules. Correctly diagnosed individuals underwent medical treatment and cure; misdiagnosed individuals had an increased risk of death. Cohorts were followed for one year from a healthcare perspective. Our primary model focused on bacteremia, with separate secondary UTI and meningitis models. One-way, structural, and probabilistic sensitivity analyses were performed. Main outcomes were SBI correctly diagnosed and incremental cost per quality-adjusted life-year (QALY).

Results: For bacteremia, PECARN was favored ($3,433, 0.778 QALYs); other strategies were less effective and more costly. Results were sensitive to mortality risk after misdiagnosis, hospitalization utility, and bacteremia risk. The addition of empiric ceftriaxone to the Boston and Philadelphia strategies did not change overall results. In probabilistic sensitivity analyses, PECARN was favored in 88% of model iterations at a $100,000/QALY acceptability threshold. In the UTI and meningitis models, PECARN was the favored strategy, with results sensitive to selected clinical decision rule specificity.
Conclusion(s): The PECARN decision rule offers an economically reasonable strategy compared to alternatives for the evaluation of bacteremia, UTI, and meningitis in young, febrile infants. Our findings support external validation of decision rules for this population and highlight the benefits of a clinical decision rule that minimizes false positive findings and avoids potentially unnecessary hospitalizations.