Modification of Initial Empirical Antibiotic Prescription and its Impact on Patient Outcome: Experience of an Indian Intensive Care Unit

Introduction: Data on the overall impact of antibiotic modification following initial empiric prescription in both culture-positive and culture negative critically ill patients are exiguous.Materials and methods: In a retrospective analysis of "ANT-CRITIC" study, we classified ICU patients receiving empirical antibiotics who remained in the ICU for >72 hours or till availability of culture results (whichever is longer) into five groups based on culture results and antibiotic modification: negative culture, no change (group I), positive culture, no change (group II), positive culture, de-escalation (group III), positive culture, escalation (group IV) and negative culture, antibiotic modification (group V). Baseline variables and clinical outcomes were compared. Logistic regression analysis was performed to look for independent variables associated with mortality.Results: 276 prescription episodes were analyzed. Group II was associated with worsening organ dysfunction at 72 hours, lower clinical cure rate at day 7, and higher hospital mortality. There was an independent association between group II prescription and hospital mortality [adjusted OR 2.774 (CI 1.178-6.533), p = 0.02]. Group III received longer duration of antibiotic (mean duration = 8.27 & PLUSMN; 4.11 days, median duration = 7 days [IQR 5-11]).Conclusion: Outcomes of critically ill infected patients differ significantly when they are classified based on culture result and antibiotic modification pattern.