Effectiveness of oral step-down therapy and early oral switch for bloodstream infections caused by Enterobacterales: a post hoc emulation trial of the SIMPLIFY trial

Abstract

Objectives: We investigated the effectiveness of early oral switch for treating Enterobacterales bloodstream infection (BSI) by performing a post hoc emulation trial of the SIMPLIFY trial. Methods: We conducted a post hoc analysis of a randomized controlled trial. We specified the target trial characteristics selecting patients who achieved clinical stability on day 5. We categorized patients into those who switched on day 5 and those who continued intravenously. The primary outcome was clinical cure at the test of cure. We set a propensity score for being switched on day 5 to reduce confounding. We ran simple, not-propensity-adjusted, and propensity-adjusted logistic regression models to ascertain the association of switch on day 5 with clinical cure. Results: Among 303 patients who achieved clinical stability on day 5, 110 (36.3%) were switched orally on day 5, and 193 (63.7%) were kept intravenously. We detected no difference in clinical cure between those switched on day 5 and those continued intravenously (risk ratios 1.04, 95% confidence intervals [CI] 0.98-1.10). Propensity-adjusted analysis did not show an association between day 5 switch and clinical cure (OR 2.10, 95% CI 0.96-7.41). Conclusion: Oral step-down therapy on day 5 was not associated with worse clinical cure for Enterobacterales BSI.