Predicting Maintenance Doses of Vancomycin for Hospitalized Patients Undergoing Hemodialysis.
Methicillin-resistantStaphylococcus aureusis a leading cause of death in patients undergoing hemodialysis. However, controversy exists about the optimal dose of vancomycin that will yield the recommended pre-hemodialysis serum concentration of 15-20 mg/L.



To develop a data-driven model to optimize the accuracy of maintenance dosing of vancomycin for patients undergoing hemodialysis.



A prospective observational cohort study was performed with 164 observations obtained from a convenience sample of 63 patients undergoing hemodialysis. All vancomycin doses were given on the floor after completion of a hemodialysis session. Multivariate linear generalized estimating equation analysis was used to examine independent predictors of pre-hemodialysis serum vancomycin concentration.



Pre-hemodialysis serum vancomycin concentration was independently associated with maintenance dose (B= 0.658,p< 0.001), baseline pre-hemodialysis serum concentration of the drug (B= 0.492,p< 0.001), and interdialytic interval (B= -2.133,p< 0.001). According to the best of 4 models that were developed, the maintenance dose of vancomycin required to achieve a pre-hemodialysis serum concentration of 15-20 mg/L, if the baseline serum concentration of the drug was also 15-20 mg/L, was 5.9 mg/kg with interdialytic interval of 48 h and 7.1 mg/kg with interdialytic interval of 72 h. However, if the baseline pre-hemodialysis serum concentration was 10-14.99 mg/L, the required dose increased to 9.2 mg/kg with an interdialytic interval of 48 h and 10.0 mg/kg with an interdialytic interval of 72 h.



The maintenance dose of vancomycin varied according to baseline pre-hemodialysis serum concentration of the drug and interdialytic interval. The current practice of targeting a pre-hemodialysis concentration of 15-20 mg/L may be difficult to achieve for the majority of patients undergoing hemodialysis.
PharmD, BCPS, BCACP, was, at the time of this study, a Resident at St John Hospital and Medical Center in Detroit, Michigan. At the time of submission, he was a Clinical Pharmacy Specialist with the Departments of Pharmacy and Nephrology, Windsor Regional Hospital, Windsor, Ontario, and he is now a Senior Pharmacotherapy Specialist - Nephrology with the Department of Pharmacy, Cleveland Clinic Abu Dhabi, United Arab Emirates.
Wasim S
WS
El Nekidy
PhD, RN, is Professor and Research Leadership Chair, Faculty of Nursing, University of Windsor, Windsor, Ontario.
Maher M
MM
El-Masri
PharmD, is a Clinical Pharmacy Specialist, St John Hospital and Medical Center, Detroit, Michigan.
Greg S
GS
Umstead
PharmD, is Manager of Patient Care Services, St John Hospital and Medical Center, Detroit, Michigan.
Michelle
M
Dehoorne-Smith
dosing; hemodialysis; vancomycin