Vancomycin monitoring strategies show discordance; `rs2789047` variant impacts exposure and VA-AKI risk
Background
Optimizing vancomycin efficacy while minimizing vancomycin-associated acute kidney injury (VA-AKI) is critical. Recent guidelines recommend AUC24/MIC-based monitoring over trough concentrations, yet the impact of different AUC24/MIC estimation methods (e.g., pharmacokinetic equations vs. Bayesian approaches) on therapeutic classification remains unclear. Furthermore, interindividual variability in vancomycin exposure, partly due to pharmacogenetic factors, is not fully characterized, posing challenges for precise dosing and risk stratification.
Study Design
This prospective, single-center cohort study enrolled 36 adult patients receiving intravenous vancomycin for at least 72 hours. Vancomycin trough and peak plasma concentrations were measured using an enzyme-linked immunosorbent assay. AUC24/MIC values were calculated via both pharmacokinetic equations and Bayesian methods. Researchers assessed the agreement in therapeutic classification between trough concentration-based and AUC24/MIC-based monitoring. Additionally, associations between the rs2789047 genetic variant and vancomycin pharmacokinetic parameters were evaluated.
Results
Of the 36 patients included, 38.9% developed vancomycin-associated acute kidney injury (VA-AKI). Strong correlations were observed between trough concentrations and AUC24/MIC values (r = 0.84-0.87). However, substantial discordance in therapeutic classification was evident: > Trough concentration-based monitoring showed agreement rates of only 63.9% with pharmacokinetic equation-based AUC24/MIC and 66.7% with Bayesian-based AUC24/MIC methods. In contrast, pharmacokinetic equation-based and Bayesian-based AUC24/MIC methods demonstrated strong concordance (86.1%). Higher trough concentrations and AUC24/MIC values were significantly associated with VA-AKI (p < 0.001). Carriers of the rs2789047 A-allele exhibited higher trough concentrations and reduced vancomycin elimination rates, suggesting a genetic predisposition to altered drug exposure.
Key Findings
- 38.9% of patients receiving vancomycin developed vancomycin-associated acute kidney injury (VA-AKI).
- Trough-based monitoring showed only 63.9% to 66.7% agreement with
AUC24/MICmethods for therapeutic classification. - Higher trough concentrations and
AUC24/MICvalues were significantly associated with VA-AKI (p < 0.001). - Carriers of the
rs2789047A-allele exhibited higher vancomycin trough concentrations and reduced elimination rates.
Why It Matters
This study highlights critical discrepancies between vancomycin therapeutic drug monitoring (TDM) strategies, suggesting that switching from trough-based to AUC24/MIC-based monitoring without considering the estimation method could alter therapeutic classification for a significant portion of patients. Clinicians and pharmacists should be aware of the potential for different AUC24/MIC calculation methods to yield distinct therapeutic recommendations. The finding that the rs2789047 genetic variant influences vancomycin exposure and VA-AKI risk opens avenues for personalized dosing strategies. Integrating pharmacogenetic testing could help identify patients at higher risk of toxicity, allowing for proactive dose adjustments and potentially reducing VA-AKI incidence, moving towards more precise and safer vancomycin protocols.
vancomycin
therapeutic-drug-monitoring
pharmacokinetics
pharmacogenetics
acute-kidney-injury
cohort-study