Association between colistin dose and microbiologic outcomes in patients with multi-drug resistant gram-negative bacteremia.
Clin Infect Dis. 2012 Oct 22;
Authors: Vicari G, Bauer SR, Neuner EA, Lam SW
Background.?Colistin is increasingly used for the treatment of multi-drug resistant gram-negative infections. However, colistin dosing varies greatly and the optimal regimen is unknown. The purpose of this study was to determine if colistin dosing correlates with patient outcomes.Methods.?This retrospective study included patients with gram-negative bacteremia treated with intravenous colistin for at least 72 hours. The primary objective was to determine if colistin dose (mg of colistin base activity/kg/day) independently predicts day 7 microbiological success. Secondary objectives included evaluation for an association between colistin dose and 7-day mortality, 28-day mortality, and the development of acute kidney insufficiency (AKI).Results.?Seventy-six patients were included in the analysis, with 52 patients (68%) achieving 7-day microbiological success. The median colistin dose was significantly higher in patients who achieved microbiological success (2.9 vs. 1.5 mg/kg/day; p=0.011). After adjusting for baseline severity of illness and concomitant tigecyline use, higher colistin dose independently correlated with microbiological success (aOR per 1 mg/kg/day = 1.74; 95% CI 1.11 - 2.71; p = 0.015). The median colistin dose was also significantly higher among survivors at day 7 (2.7 vs. 1.5 mg/kg/day; p=0.007). However, no difference was observed in colistin dose when comparing survivors and non-survivors at day 28. A significantly higher colistin dose was given to patients who developed AKI during therapy (3.8 vs. 1.6 mg/kg/day, p<0.001).Conclusions.?Higher colistin dose independently predicted microbiological success, which may partially explain the similar association with 7-day mortality. However, higher colistin doses may also precipitate worsening renal function.
PMID: 23090926 [PubMed - as supplied by publisher]