Decreased Kidney Function Explains Higher Vancomycin Exposure in Older Adults.

Area of Science:

• Pharmacology
• Nephrology
• Geriatrics

Background:

• Older adults are susceptible to vancomycin toxicity due to physiological changes.
• Limited data exists on vancomycin exposure in the elderly population.
• Early management of supratherapeutic vancomycin levels is critical in older patients.

Purpose of the Study:

• To compare vancomycin concentrations between older and younger adult patients.
• To identify factors associated with supratherapeutic vancomycin exposure in different age groups.
• To investigate the impact of patient characteristics on vancomycin levels.

Main Methods:

• Observational retrospective study design.
• Analysis of initial vancomycin concentrations in patients aged ≥75 years versus <75 years.
• Multivariable logistic and linear regression analyses to assess determinants of supratherapeutic and dose-normalized concentrations.

Main Results:

• Older adults exhibited significantly higher initial vancomycin concentrations and supratherapeutic rates (30.7% vs 21%).
• Decreased estimated glomerular filtration rate (eGFR_CKD-EPI) was associated with supratherapeutic concentrations and increased dose-normalized concentrations.
• Lower loading and maintenance doses were linked to lower supratherapeutic concentrations.

Conclusions:

• Reduced eGFR_CKD-EPI, rather than age itself, appears to mediate vancomycin exposure in older adults.
• Older patients may experience greater benefits from vancomycin therapeutic drug monitoring (TDM).
• Optimizing vancomycin dosing and monitoring is essential for safe and effective treatment in the elderly.