LAUSR

The Infectious Diseases Society of America (IDSA) and Society for Healthcare Epidemiology of America (SHEA) revised their Clostridioides difficile infection (CDI) severity classification criteria in 2017 to include a serum creatinine (SCr) value above a threshold (≥ 1.5 mg/dL) rather than a relative increase from baseline (≥ 1.5 times the premorbid level). To date, these criteria have not been validated and may overestimate the number of severe CDI cases in patients with underlying renal insufficiency. This multicenter, retrospective cohort study included all patients ≥ 18 years of age with CDI diagnosed in two large health systems in the Houston, Texas area between 2016 and 2018. Patients were assessed for presence of acute kidney injury (AKI) and chronic kidney disease (CKD), defined per the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines, and IDSA/SHEA CDI severity classification criteria per the 2010 and 2017 CDI guidelines. The primary outcome was all-cause inpatient mortality. The study cohort consisted of 770 CDI episodes from 12 hospitals. A large proportion of episodes occurred in patients with preexisting CKD (36.5%) and concomitant AKI (29.6%). Eighty-two episodes (10.6%) showed discordant results when applying the 2017 revised severity classification criteria due to the identification of patients with preexisting CKD. However, the 2017 severity classification criteria were better correlated with all-cause mortality (OR, 5.40; 95% CI, 1.84-15.86; P = 0.002) than were the 2010 severity classification criteria (OR, 3.12; 95% CI, 1.35-7.19; P = 0.008) as the 2017 SCr criterion was an independent predictor of mortality (OR, 3.66; 95% CI, 1.66-8.05; P = 0.001) while the 2010 SCr criterion was not (OR, 1.47; 95% CI, 0.71-3.08; P = 0.30). Our findings support the inclusion of the 2017 IDSA/SHEA CDI severity classification criteria in future CDI guideline updates. Kevin W. Garey, PharmD, MS, FASHP, Merck & Co. (Grant/Research Support, Scientific Research Study Investigator)