Implementation of vancomycin AUC/MIC dosing vs traditional trough dosing and incidence of acute kidney injury at a rural community hospital

Better together? Reducing vancomycin use and acute kidney injury with a blended AUC and trough-based dosing guideline

BACKGROUND

Vancomycin guidelines recommend area-under-the-curve (AUC) therapeutic monitoring for patients with severe methicillin-resistant Staphylococcus aureus (MRSA) infections. No recommendations exist for patients with non-severe staphylococcal infections or those with other Gram-positive infections. AUC-based vancomycin dosing can be resource-intensive and may not be necessary for all patients.

METHODS

New institutional guidelines for vancomycin dosing were implemented across an eight-hospital health system in 2023. The new guidelines recommended either AUC or trough-based dosing depending on the severity of the infection and the likelihood of MRSA. Adult patient encounters with at least one vancomycin administration were compared retrospectively 6 months pre-implementation and 6 months post-implementation. Cumulative vancomycin dose, administrations, and serum levels were assessed. The rate of acute kidney injury (AKI) was compared in a subgroup of patient encounters with four or more administrations. Pharmacist time saved using a blended approach compared to a uniform AUC dosing guideline was estimated based on the number of patients receiving trough-based dosing in the post-implementation group.

RESULTS

A total of 8155 patient encounters were included in the analysis (3916 pre-implementation, 4239 post-implementation). The primary outcome of median cumulative vancomycin dose (mg) was 500 mg lower in the post-implementation group (3000 mg pre-implementation vs 2500 mg post-implementation, Odds ratio [OR] 0.94 95% confidence interval [CI] 0.90-0.97, p < 0.001). Patients in the post-implementation group were significantly less likely to have vancomycin serum levels drawn (OR 0.86; 95% CI 0.78, 0.96, p = 0.005). A subgroup of patient encounters receiving four or more vancomycin administrations included 2483 patient encounters (1251 pre-implementation, 1232 post-implementation). AKI occurred in 120 (9.6%) cases pre-implementation and 89 (7.2%) cases post-implementation. The risk of AKI was significantly lower post-implementation (OR 0.73; 95% CI 0.55, 0.98, p = 0.038). Estimated pharmacist time saved was between 2229 to 5201 min, equating to an estimated $16,851.24 to $39,319.56 saved over 6 months, with blended vancomycin dosing.

CONCLUSION

In this large multi-hospital cohort, the implementation of a blended dosing method using a majority of AUC-based dosing reduced cumulative vancomycin doses, serum levels, and AKI. Including trough recommendations for patients with less severe infections and non-MRSA, Gram-positive pathogens may have saved significant pharmacist time and associated costs compared to a uniform AUC dosing policy. This study further highlights the sizeable amount of unnecessary vancomycin use with a corresponding low incidence of severe MRSA infections.

Effect of low vs. high vancomycin trough level on the clinical outcomes of adult patients with sepsis or gram-positive bacterial infections: a systematic review and meta-analysis

BACKGROUND & OBJECTIVE

The Infectious Disease Society of America guidelines recommend vancomycin trough levels of 15-20 mg/L for severe methicillin-resistant Staphylococcus aureus. However, recent consensus guidelines of four infectious disease organizations no longer recommend vancomycin dosing using minimum serum trough concentrations. Therefore, this study aimed to evaluate the impact of low (< 15 mg/L) vs. high (≥ 15 mg/L) vancomycin trough levels on clinical outcomes in adult patients with sepsis or gram-positive bacterial infections.

METHOD

A systematic literature review from inception to December 2022 was conducted using four online databases, followed by a meta-analysis. The outcomes of interest included clinical response/efficacy, microbial clearance, length of ICU stay, treatment failure, nephrotoxicity, and mortality.

RESULTS

Fourteen cohort studies met the inclusion criteria from which vancomycin trough concentration data were available for 5,228 participants. Our analysis found no association between vancomycin trough levels and clinical response [OR = 1.06 (95%CI 0.41-2.72], p = 0.91], microbial clearance [OR = 0.47 (95% CI 0.23-0.96), p = 0.04], ICU length of stay [MD=-1.01 (95%CI -5.73-3.71), p = 0.68], or nephrotoxicity [OR = 0.57 (95% CI 0.31-1.06), p = 0.07]. However, low trough levels were associated with a non-significant trend towards a lower risk of treatment failure [OR = 0.89 (95% CI 0.73-1.10), p = 0.28] and were significantly associated with reduced risk of all-cause mortality [OR = 0.74 (95% CI 0.62-0.90), p = 0.002].

CONCLUSION

Except for a lower risk of treatment failure and all-cause mortality at low vancomycin trough levels, this meta-analysis found no significant association between vancomycin trough levels and clinical outcomes in adult patients with sepsis or gram-positive bacterial infections.

Tumour lysis syndrome

Tumour lysis syndrome (TLS) represents a critical oncological emergency characterized by extensive tumour cell breakdown, leading to the swift release of intracellular contents into the systemic circulation, outpacing homeostatic mechanisms. This process results in hyperuricaemia (a by-product of intracellular DNA release), hyperkalaemia, hyperphosphataemia, hypocalcaemia and the accumulation of xanthine. These electrolyte and metabolic imbalances pose a significant risk of acute kidney injury, cardiac arrhythmias, seizures, multiorgan failure and, rarely, death. While TLS can occur spontaneously, it usually arises shortly after the initiation of effective treatment, particularly in patients with a large cancer cell mass (defined as ≥500 g or ≥300 g/m2 of body surface area in children). To prevent TLS, close monitoring and hydration to improve renal perfusion and urine output and to minimize uric acid or calcium phosphate precipitation in renal tubules are essential. Intervention is based on the risk of a patient of having TLS and can include rasburicase and allopurinol. Xanthine, typically enzymatically converted to uric acid, can accumulate when xanthine oxidases, such as allopurinol, are administered during TLS management. Whether measurement of xanthine is clinically useful to optimize the use of allopurinol or rasburicase remains to be determined.

Vancomycin-Induced Neutropenia With Subsequent Perioperative Readministration: A Case Report

Vancomycin (VCM), an essential antibiotic for antimicrobial-resistant Gram-positive cocci, can lead to complications such as neutropenia. Here, we present a case of a 25-year-old male with noncommunicating hydrocephalus due to an intraventricular tumor who developed neutropenia during VCM therapy. Despite the suspected VCM-induced neutropenia, short-term readministration was deemed necessary for perioperative infection prophylaxis. This patient was readministered without neutropenia. A review of the literature revealed an earlier onset of VCM-induced neutropenia than that previously reported, emphasizing the importance of vigilant monitoring. Although readministration of VCM in patients with neutropenia is uncommon, it may be feasible with careful risk assessment, particularly in cases of mild neutropenia and short-term therapy. However, the mechanisms underlying VCM-induced neutropenia remain unclear, necessitating further research on the optimal management strategies.