Colistin treatment in carbapenem-resistant Acinetobacter baumannii pneumonia patients: Incidence of nephrotoxicity and outcomes

Colistimethate sodium (CMS) is increasingly used to treat multidrug-resistant Gram-negative bacilli infections. However, the incidence of CMS-associated nephrotoxicity has not been evaluated in patients with carbapenem-resistantAcinetobacter baumannii (CRAB) pneumonia. This retrospective study included 120 patients with CRAB pneumonia treated with intravenous CMS for >= 72 h. The objective of the study was to determine risk factors for CMS-induced nephrotoxicity and 30-day mortality in patients with CRAB pneumonia. Of the 120 patients with CRAB pneumonia, 61(51%) developed nephrotoxicity. Multivariate analysis showed that dose per ideal body weight (IBW) [odds ratio ( OR) = 1.28, 95% confidence interval (CI) 1.01-1.62; P=0.04], Charlson co-morbidity index (OR = 1.31, 95% CI 1.06-1.60; P=0.01) and septic shock (OR = 3.16, 95% CI 1.32-7.60; P=0.01) were associated with CMS-associated nephrotoxicity. Thirty-day mortality was 33% (391120). Multivariate analysis showed that higher daily doses of CMS per IBW [hazard ratio (HR) = 0.81, 95% CI 0.67-0.98; P=0.03] and longer duration of CMS therapy (HR = 0.86, 95% CI 0.79-0.95; P=0.002) were associated with increased survival. Septic shock (HR = 3.91, 95% CI 1.95-7.83; P<0.001) and corticosteroid use (HR = 3.49, 95% CI 1.67-7.28; P = 0.001) were associated with decreased survival in patients with CRAB pneumonia. Higher daily doses of CMS per IBW, Charlson comorbidity index and septic shock were significant risk factors for CMSas sociated nephrotoxicity. However, CMS-associated nephrotoxicity does not appear to have an impact on mortality. (C) 2015 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.