The adequacy of vancomycin initial dosing in CRBSI for hemodialysis patients in a specialized district hospital of Malaysia.

Background

Catheter-related bloodstream infections (CRBSIs) are a common complication in hemodialysis (HD) patients with central venous catheters (CVCs), and are often caused by Methicillin-Resistant Staphylococcus aureus (MRSA). Vancomycin is the preferred first-line treatment for MRSA-related CRBSI. At Hospital Pakar Sultanah Fatimah (HPSF), the current protocol for CRBSI in HD patients involves a weight-based intravenous (IV) vancomycin loading dose (LD) of 25 mg/kg, followed by therapeutic drug monitoring (TDM) within 48 hours post-administration. This study evaluates the adequacy of the initial dosing regimen in achieving the target serum vancomycin concentration (SVC) of 15-20 mcg/ml.

Methods

A retrospective cross-sectional study was conducted among hospitalized HD patients receiving IV vancomycin from July 1, 2022, to July 31, 2023. Data were collected from TDM request orders in the Pharmacy Information System (PhIS). The primary outcomes analyzed were the proportion of patients achieving the target SVC and factors influencing vancomycin pharmacokinetics. Multiple linear regression was used to assess associations between SVC and variables such as time-to-first-sampling (TTFS), age, and initial vancomycin dose.

Results

A total of 106 TDM samples were analyzed. The mean vancomycin LD was 1568.2 mg (SD 303.6), with a mean TTFS of 41.2 hours (SD 11.8). Only 32.1% of patients achieved the target SVC, while 56.6% had subtherapeutic levels and 11.3% had supratherapeutic levels. Multiple linear regression identified TTFS (p=0.003), age (p=0.002), and initial dose (p=0.004) as significant predictors of SVC.

Conclusion

The current vancomycin dosing protocol at HPSF does not consistently achieve therapeutic SVC in HD patients with CRBSI. Increasing the LD to 25-35 mg/kg and optimizing TTFS within 24-48 hours may improve target attainment. Further studies are needed to validate these findings and refine vancomycin dosing strategies in HD patients.