Parenteral colistin for the treatment of severe infections: a single center experience

OBJECTIVE: To describe a single center experience involving the administration of colistin to treat nosocomial infections caused by multidrug-resistant Gram-negative bacteria and identify factors associated with acute kidney injury and mortality. METHODS: This retrospective longitudinal study evaluates critically ill patients with infections caused by multidrug-resistant Gram-negative bacteria. All adult patients who required treatment with intravenous colistin (colistimethate sodium) from January to December 2008 were considered eligible for the study. Data include demographics, diagnosis, duration of treatment, presence of acute kidney injury and 30-day mortality. RESULTS: Colistin was used to treat an infection in 109 (13.8%) of the 789 patients admitted to the intensive care unit. The 30-day mortality observed in these patients was 71.6%. Twenty-nine patients (26.6%) presented kidney injury prior to colistin treatment, and six of these patients were able to recover kidney function even during colistin treatment. Twenty-one patients (19.2%) developed acute kidney injury while taking colistin, and 11 of these patients required dialysis. The variable independently associated with the presence of acute kidney injury was the Sequential Organ Failure Assessment at the beginning of colistin treatment (OR 1.46; 95%CI 1.20-1.79; p<0.001). The factors age (OR 1.03; 95%CI 1.00-1.05; p=0.02) and vasopressor use (OR 12.48; 95%CI 4.49-34.70; p<0.001) were associated with death in the logistic-regression model. CONCLUSIONS: Organ dysfunction at the beginning of colistin treatment was associated with acute kidney injury. In a small group of patients, we were able to observe an improvement of kidney function during colistin treatment. Age and vasopressor use were associated with death.