Comparison of trough-only-based area under the concentration–time curve and trough levels in predicting vancomycin nephrotoxicity in late elderly

Abstract

The guidelines for TDM of vancomycin was updated in 2022, and AUC-guided dosing is more strongly recommended than conventional trough-guided dosing, to decrease the risk of vancomycin-associated nephrotoxicity. The calculation of AUC requires a peak level in addition to the trough level, creating a burden associated with increased blood sampling. Prior studies have shown the usefulness of Trough-only-based AUC, but none have been reported in the late elderly. In this study, we retrospectively examined the usefulness of trough-only-based AUC in the late elderly. Sixty-one patients were included, and seven of whom developed acute kidney injury. Patients were matched by calculating a propensity score using risk factors for acute kidney injury and hemoglobin as covariates. After propensity score matching, 7 patients were in the group with acute kidney injury and 7 were in the group without acute kidney injury. Trough-only-based AUC (>600 μg·hr/mL, and>450 μg·hr/mL) was not significantly different in sensitivity,specificity, positive predictive value, or negative predictive value compared to estimated steady-state trough level (≥ 15 μg/mL). Area under the ROC curve predicting acute kidney injury was not significantly different between estimated steady-state trough level and trough-only-based AUC (0.714[95% confidence interval 0.409–1.000]vs 0.735[95% confidence interval 0.443– 1.000], P =0.480). In conclusion, AUC-guided dosing did not differ in acute kidney injury predictive performance compared with trough-guided dosing in patients aged 75 years or older, suggesting that it may not be useful.