Vancomycin in ICU Patients with Gram-Positive Infections: Initial Trough Levels and Mortality

Abstract

Background

Vancomycin is one of the most common therapeutic agents for treating gram-positive infections, particularly in critically ill patients. The aim of this study was to identify factors associated with initial therapeutic vancomycin trough levels and mortality in a tertiary-care intensive care unit (ICU).

Methods

This retrospective study evaluated 301 adult ICU patients admitted to King Abdulaziz Medical City in Riyadh between October 1, 2017 and December 31, 2018 with confirmed gram-positive infections and received intravenous vancomycin. Vancomycin trough levels of 15–20 mg/L for severe infections and 10–15 mg/L for less severe infections were considered therapeutic.

Results

The patients were relatively older with a mean age of 60 (SD ±20) years. Initial vancomycin trough levels were therapeutic in 168 (55.8%). Factors associated with initial therapeutic vancomycin trough levels were female gender (adjusted odds ratio [aOR]=2.575), older age (aOR=1.024), receiving a loading dose (aOR=2.445), having bacteremia (aOR=2.061), and high platelet count (aOR=1.003). On the other hand, the increase of estimated glomerular filtration rate (eGFR) (aOR=0.993) and albumin levels (aOR=0.944) were associated with lower odds of initial therapeutic vancomycin trough levels. Factors associated with higher mortality were female gender (adjusted hazard ratio [aHR]=2.630), increased body weight (aHR=1.021), cancer (aHR=3.451), and high APACHE II score (aHR=1.068).

Conclusion

The study identified several factors associated with achieving initial therapeutic vancomycin trough levels (i.e. older age, female gender, receiving a loading dose, bacteremia, high platelets count, low eGFR and albumin level). These factors should be considered in the dosing of vancomycin in critically ill patients with gram-positive infections.

Keywords:

• vancomycin dosage
• pharmacokinetics
• renal function
• serum trough levels
• mortality

Abbreviations

VIS, vasoactive-inotropic score; APACHE, Acute Physiology Assessment and Chronic Health Evaluation II; MV, mechanical ventilation; MRSA, methicillin-resistant staphylococcus aureus; MSSA, methicillin-susceptible staphylococcus aureus; GCS, Glasgow coma scale.

Data Sharing Statement

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

Ethics Approval and Informed Consent

This research was approved by King Abdullah International Medical Research Center IRB; SP19/025/R. All patient data accessed complied with relevant data protection and privacy regulations.

Acknowledgments

The authors would like to acknowledge Nadin Al-Anazi (Pharmacist in King Abdulaziz Medical City, Riyadh) for helping in collecting the research data.

Author Contributions

All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.

Disclosure

The authors declare that they have no competing interests for this work.

Additional information

Funding

This research did not receive any funding.