Efficacy of Vancomycin on Gram-Positive Bacterial Infection in Elderly Critical Patients and Risk Factors Associated With Nephrotoxicity

Vancomycin is widely used for infections caused by gram-positive bacteria, but little attention has been paid to vancomycin in the treatment of critically ill patients aged ≥80 years. The aim of the current study was to investigate the efficacy of vancomycin and risk factors associated with nephrotoxicity of vancomycin in elderly critically ill patients.
A retrospective study was performed in a 14-bed medical-surgical geriatric ICU between January 2007 and June 2014. The patients (aged ≥80 years) were included if they received ≥4 doses of vancomycin and the therapy duration was ≥ 2 hours.
The clinical efficacy was 74.0% (37/50). The 28-day mortality was 26.0% (13/50). Of the patients, 24% (12/50) had nephrotoxicity during vancomycin treatment period. The clinical efficacy was 60%, 86.7%, 58.3%, and 33.3%, and the 28-day mortality rate was 20%, 23.3%, 33.3%, and 33.3%, respectively, when the trough concentrations were ≤10 μg/mL, 10–15 μg/mL, 15–20 μg/mL, and ≥20 μg/mL. The multivariate logistic regression analysis showed that an Acute Physiology and Chronic Health Evaluation (APACHE) II score ≥25 points, vancomycin trough concentrations ≥15 μg/mL, and the combined use of diuretics (furosemide ≥40 mg/d) were independent risk factors leading to nephrotoxicity.
We did not find that higher vancomycin trough concentrations lead to better clinical outcomes in elderly critically ill patients. Increased vancomycin trough concentrations, high APACHE II scores, and the combined use of diuretics may increase the risks of nephrotoxicity in elderly critically ill patients.