Background: Overuse of broad-spectrum antibiotics results in microbial resistance and financially is a healthcare burden. Antibiotic de-escalation refers to starting treatment of a presumed infection with broad-spectrum antibiotics and narrowing drug spectrum based on culture sensitivities. A study was designed to evaluate antibiotic de-escalation at a tertiary care center. We hypothesized that antibiotic de-escalation would not be associated with increased patient mortality rates or worsening of the primary infection.
Methods: All infections treated in a single, tertiary care Surgical ICU between August 2009 and December 2011 were reviewed. Antibiotic treatment was classified by skilled reviewers as being either de-escalated or not. Outcomes were evaluated. Univariate statistics were performed (Fisher exact test, Chi-square for categorical data; student t-test for continuous variables). Multivariable logistic regression was completed.
Results: A total of 2,658 infections were identified. De-escalation was identified for 995 infections and non-deescalation occurred in 1,663. Patients were similar in age (de-escalated 55 ± 16 y vs. 56 ± 16, p = 0.1) and gender (de-escalated 60% males vs. 58%, p = 0.4). There were substantially greater APACHE II scores in non-deescalated patients (15 ± 8 vs. 14 ± 8, p = 0.03). A greater mortality rate among patients with infections treated without de-escalation was observed compared with those treated with de-escalation (9% vs. 6%, p = 0.002). Total antibiotic duration was substantially longer in the de-escalated group (15 ± 13 d vs. 13 ± 13, p = 0.0001). Multivariable analysis found that de-escalation decreased mortality rates (OR = 0.69; 95%CI, 0.49-0.97; p = 0.04) and high APACHE II score independently increased mortality rates (OR = 1.2; 95%CI, 1.1-1.2; p = 0.0001). Other parameters included were age and infection site.
Conclusions: Antibiotic de-escalation was not associated with increased mortality rates, but the duration of antibiotic use was longer in this group. Greater mortality rates were observed in the non-deescalated group, but this likely owes at least in part to their relatively greater severity of disease classification (APACHE II). Further investigation will help evaluate whether antibiotic de-escalation will improve the quality of patient care.