An Evaluation of Antimicrobial Prescribing and Risk-adjusted Mortality

The Centers for Disease Control and Prevention recommends tracking risk-adjusted antimicrobial prescribing. Prior studies have used prescribing variation to drive quality improvement initiatives without adjusting for severity of illness. The present study aimed to determine the relationship between antimicrobial prescribing and risk-adjusted ICU mortality in the Pediatric Health Information Systems (PHIS) database, assessed by IBM-Watson risk of mortality. A nested analysis sought to assess an alternative risk model incorporating laboratory data from federated electronic health records. METHODS: Retrospective cohort study of pediatric ICU patients in PHIS between 1/1/2010 and 12/31/2019, excluding patients admitted to a neonatal ICU, and a nested study of PHIS+ from 1/1/2010 to 12/31/2012. Hospital antimicrobial prescription volumes were assessed for association with risk-adjusted mortality. RESULTS: The cohort included 953,821 ICU encounters (23,851 [2.7%] nonsurvivors). There was 4-fold center-level variability in antimicrobial use. ICU antimicrobial use was not correlated with risk-adjusted mortality assessed using IBM-Watson. A risk model incorporating laboratory data available in PHIS+ significantly outperformed IBM-Watson (c-statistic 0.940 [95% confidence interval 0.933–0.947] versus 0.891 [0.881–0.901]; P < 0.001, area under the precision recall curve 0.561 versus 0.297). Risk-adjusted mortality was inversely associated with antimicrobial prescribing in this smaller cohort using both the PHIS+ and Watson models (P = 0.05 and P < 0.01, respectively). CONCLUSIONS: Antimicrobial prescribing among pediatric ICUs in the PHIS database is variable and not associated with risk-adjusted mortality as assessed by IBM-Watson. Expanding existing administrative databases to include laboratory data can achieve more meaningful insights when assessing multicenter antibiotic prescribing practices.