489. Validation of the SHEA/IDSA Severity Criteria to Predict Poor Outcomes Among Inpatients and Outpatients With Clostridium difficile Infection

BACKGROUND: The SHEA/IDSA clinical practice guidelines suggest using leukocytosis (WBC ≥15,000 cells/µl) and serum creatinine (SCr) to identify severe cases of Clostridium difficile infection (CDI). It is unclear whether these criteria adequately predict poor outcomes among patients with CDI in the inpatient and outpatient settings METHODS: Retrospective cohort study of patients with CDI in the Veterans Affairs Health System from January 1, 2006 to December 31, 2016. Patients were included the first time they had a positive laboratory test indicating toxin or toxin genes from a stool sample and were followed for poor outcomes - defined as hospital or intensive care unit admission within 7 days of diagnosis, colectomy within 14 days of diagnosis, or 30-day all-cause mortality. Severity was defined according to the 2010 and 2018 versions of the criteria. For the 2010 criteria, patients with leukocytosis or a serum creatinine 1.5 times or more than the baseline were classified as severe. For the 2018 criteria, patients with leukocytosis or a SCr value ≥1.5 mg/dL were classified as severe. Maximum WBC and SCr values were assessed within 3 days prior to diagnosis. Baseline SCr was calculated as the average of SCr levels from 4 to 90 days prior to diagnosis. Poor outcome was modeled as a function of the 2010 and 2018 severity criteria separately using logistic regression. Criteria were assessed using the sensitivity (Sn), false negative (FN) rate, positive predictive value (PPV), and the area under the curve (AUC) RESULTS: We analyzed data from 86,112 episodes of CDI. According to the 2010 and 2018 criteria, 29.9% and 44.0% of episodes would be classified as severe. Severity could not be determined due to missing data in 16.3% and 15.0% of episodes, respectively. Seventy-five% of unclassified episodes were among outpatients. The 2018 severity criteria had a higher Sn (65.2% vs. 48.4%) but lower PPV (28.5% vs. 30.7%) than the 2010 criteria. The FN rate was lower for the 2018 criteria (34.8% vs. 51.6%), and AUCs were poor and similar (.587 vs. .582) CONCLUSION: Although the 2018 CDI severity criteria would allow for classification of more cases and result in fewer false negatives, the performance remains poor. More work is needed to develop criteria to reliably and prospectively identify patients at risk of poor outcomes DISCLOSURES: All authors: No reported disclosures.