Nephrotoxicity of vancomycin in patients with methicillin-resistant Staphylococcus aureus bacteraemia

Impact of decreasing vancomycin exposure on acute kidney injury in stem cell transplant recipients

OBJECTIVE

To evaluate the change in vancomycin days of therapy (DOT) and vancomycin-associated acute kidney injury (AKI) after an antimicrobial stewardship program (ASP) intervention to decrease vancomycin use in stable patients after hematopoietic stem cell transplantation (HSCT).

DESIGN

Retrospective cohort study and quasi-experimental interrupted time series analysis. Change in unit-level vancomycin DOT per 1,000 inpatient days after the intervention was assessed using segmented Poisson regression. Subject-specific risk of vancomycin-associated AKI was evaluated using a random intercept logistic regression model with mediation analysis.

SETTING

HSCT unit at a single quaternary-care pediatric hospital.

PARTICIPANTS

Inpatients aged 3 months and older who underwent HSCT between January 1, 2015, and March 31, 2019 (27 months before and after the intervention) who received any dose of vancomycin.

INTERVENTION

An ASP intervention in April 2017 creating a new practice guideline to decrease prolonged (>72 hours) vancomycin courses for stable HSCT patients with febrile neutropenia.

RESULTS

Overall, 439 vancomycin exposures (234 before the intervention and 205 after the intervention) occurring across 300 transplants and 259 subjects were included. The mean vancomycin DOT was 307 per 1,000 inpatient days (95% confidence interval [CI], 272-342) and decreased after the intervention to 207 per 1,000 inpatient days (95% CI, 173-240). In multivariable analyses, the odds of AKI in the postintervention period were 37% lower than in the preintervention period (adjusted OR, 0.63; 95% CI, 0.42-0.95; P = .0268); 56% of the excess risk was mediated by vancomycin DOT.

CONCLUSIONS

An ASP intervention successfully decreased vancomycin use after HSCT and resulted in a decrease in AKI. Reducing empiric antibiotic exposure for stable patients after HSCT can improve clinical outcomes.

Comparison of teicoplanin versus vancomycin in combination with piperacillin-tazobactam or meropenem for the risk of acute kidney injury

We compared the rates of acute kidney injury (AKI), 7-day and 30-day mortalities, and resolution of AKI at discharge in combination therapies involving either teicoplanin (TEI) or vancomycin (VAN) with piperacillin-tazobactam (TZP) or meropenem (MER). In a single-center, retrospective cohort study, adult patients (>18 years) who had a baseline serum creatinine level within 24 h of admission and who received study antibiotics for at least 48 h were included. The primary outcome was AKI incidence after therapy per RIFLE criteria. Multivariate logistic regression and propensity score match analyses were employed for statistical comparisons. Data from 379 patients were evaluated. In multivariate analysis (MVA) of the whole cohort, TZP-VAN combination was associated with significantly higher rate of AKI as compared with TZP-TEI (aOR: 3.21, 95% CI, 1.36-7.57; p = 0.008) or with MER-VAN (aOR: 2.28, 95% CI, 1.008-5.18; p = 0.048). In MVA of the matched cohorts, TZP-VAN as compared with TZP-TEI and MER-VAN was associated with 3.96 times (95% CI, 1.48-10.63, p = 0.006) and 3.11 times (95% CI, 1.12-8.62; p = 0.028) increased risk of AKI, respectively. No differences between MER-TEI and MER-VAN combinations were detected. Seven-day and 30-day mortalities and resolution rates of AKI were similar in all comparisons. Teicoplanin can be preferred instead of VAN when combination with TZP is used particularly for patients with high AKI risk.

Comparison of risk of acute kidney injury between patients receiving the combination of teicoplanin and piperacillin/tazobactam versus vancomycin and piperacillin/tazobactam

BACKGROUND/PURPOSE

To compare the risk of acute kidney injury (AKI) among patients receiving teicoplanin (TA) plus piperacillin/tazobactam (TZP) versus vancomycin (VAN) plus TZP.

METHODS

This was a retrospective cohort study using electronic health records. Patients were included if a combination of glycopeptide and TZP or other selected β-lactams were used during hospitalization. In the main analysis, two study groups were identified: TA + TZP and VAN + TZP. We used 1:1 propensity score matching to control for potential confounders, and hazard ratio (HR) of AKI between study groups was calculated. We further compared the risk of AKI between patients receiving VAN + TZP and VAN + β-lactams as an auxiliary analysis to verify the validity of the study design.

RESULTS

The final sample contained 211 pairs of patients receiving either TA + TZP or VAN + TZP. The median dosage of TA and VAN were 10.3 and 26.7 mg/kg/day, respectively. The median trough level of VAN was 12.3 mg/L. The AKI risk in the TA + TZP group was similar to that in the VAN + TZP group (12.3% vs. 11.4%; HR = 1.25 [0.72-2.18], p = 0.44). The auxiliary analysis showed a higher risk of AKI in the VAN + TZP group than in the VAN + β-lactam group (13.2% vs. 9.6%; HR = 1.63 [1.04-2.55], p = 0.03).

CONCLUSION

Our study results showed that the risk of AKI were similar for patients receiving TA + TZP and VAN + TZP. However, low VAN and high TA dose may play a role in this finding. Further investigation on the association between AKI and TA + TZP is required.

Vancomycin-associated acute kidney injury in Hong Kong in 2012-2016

Background

To study the incidence of vancomycin-associated acute kidney injury (VA-AKI) in Hong Kong and identify risk factors for VA-AKI.

Method

Patients with vancomycin prescription and blood level measurement in 2012–2016 were identified using the Hong Kong Hospital Authority Clinical Data Analysis and Reporting System. Acute kidney injury was defined using KDIGO criteria. Patients without creatinine measurements, steady-state trough vancomycin level or who had vancomycin treatment < 3 days were excluded. Results were analyzed using SPSS version 22.0. Logistic regression was used to identify the predictors for VA-AKI. Odds ratio and 95% confidence interval were estimated.

Results

One thousand four hundred fifty patients were identified as VA-AKI from 12,758 records in Hong Kong in 2012–2016. The incidence was respectively 10.6, 10.9, 11.3, 12.2, 11.2% from 2012 to 2016. The incidence of VA-AKI was 16.3, 12.2, 11.3 and 6.2% in patients aged 1–12, 12–60, elderly aged > 60 and newborn and infants, respectively. Baseline creatinine, serum trough vancomycin level, systematic disease history including respiratory failure, hypertension, congestive heart failure, chronic renal failure, anemia and type II diabetes, and concomitant diuretics, piperacillin-tazobactam (PTZ) and meropenem prescription were significantly higher in VA-AKI patients older than 12 years. Logistic regression showed that older age group, higher baseline creatinine, serum trough vancomycin level, respiratory failure, chronic renal failure and congestive heart failure, concomitant diuretics, PTZ and meropenem prescription, and longer hospital stay were all associated with increased risk of VA-AKI.

Conclusion

The incidence of VA-AKI in Hong Kong is low but shows no decline. Patients with higher baseline creatinine, multi-organ diseases and multiple drugs administration should have their vancomycin level monitored to decrease the risk of VA-AKI.

The Whole Price of Vancomycin: Toxicities, Troughs, and Time

Vancomycin is a glycopeptide antibiotic that is active against Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus. Nephrotoxicity, which is usually reversible, is the most serious common adverse effect of vancomycin. Vancomycin-associated nephrotoxicity prolongs hospital stays, imposes a need for additional antibiotics and, in rare circumstances, dialysis treatment, and increases medical costs and mortality. Risk factors for nephrotoxicity include the dose and duration of vancomycin treatment, serum trough concentration, patient characteristics, and concomitant receipt of nephrotoxins. Contemporary guidelines recommend targeting vancomycin trough concentrations of ≥10 mg/L to prevent resistance and trough concentrations of 15-20 mg/L to optimize outcomes. There is significant correlation between vancomycin trough serum concentrations and the incidence of vancomycin-associated nephrotoxicity; however, evidence of an association between trough concentrations and efficacy is less convincing. Routine monitoring of serum vancomycin concentrations consumes time and limited healthcare resources and may not be cost effective. The use of alternative antibacterial agents that do not require monitoring would free up pharmacy resources. This time could then be devoted to initiatives such as pharmacist-led antibiotic stewardship programs that are known to reduce antibiotic use and promote improved patient outcomes.

Acute kidney injury induced by antimicrobial agents in the elderly: awareness and mitigation strategies

The use of antimicrobial agents has increased in recent years as treatments have diversified and resistant bacteria have appeared. With increased use of antimicrobial agents, elderly patients are prone to adverse drug reactions (ADRs) as a result of factors such as drug-drug interactions, polypharmacy, long-term use, and over- or under-dosage. In particular, elderly patients using antimicrobials are at increased risk to develop drug-induced acute kidney injury (AKI), which is the most common severe ADR in such patients. AKI is a serious problem that is associated with mortality amongst hospitalized patients. Antimicrobial-induced AKI can be classified into three different types: acute tubular necrosis (ATN), acute interstitial nephritis (AIN), and renal tubule lumen obstruction. AKI can generally be prevented by proper maintenance of fluid balance. To design dosage regimens that ensure efficient drug excretion via the kidney, it is necessary to accurately estimate renal function; however, the kidney undergoes age-dependent structural and functional alterations over time. Therefore, proper management of antimicrobial agents by an antimicrobial stewardship team may lead to decreased incidence of AKI. This article reviews antimicrobial-induced AKI and discusses potential strategies for increasing awareness of AKI and mitigating its clinical effects.

Optimization of time to initial vancomycin target trough improves clinical outcomes

BACKGROUND

Outcomes data for the efficacy of interventions designed to decrease the time to initial target vancomycin troughs are sparse.

OBJECTIVE

A vancomycin therapeutic drug monitoring (TDM) program was initiated to reduce the time to initial target troughs and to examine the impact on clinical outcomes.

METHODS

Single-center, pre- and post-intervention observational study in a 250 bed teaching facility. Adult inpatients treated with physician-guided, vancomycin therapy (historical control, CTRL) were compared to high trough, pharmacist-guided vancomycin therapy (TDM). Nephrotoxicity analyses were conducted to the ensure safety of the TDM. Clinical outcome analysis was limited to patients with normal renal function and culture-confirmed gram positive infections and a pre-defined MRSA subset.

RESULTS

340 patients met initial inclusion criteria for the nephrotoxicity analysis (TDM, n = 173; CTRL, n = 167). Acute kidney injury occurrence was similar between the CTRL (n = 20) and TDM (n = 23) groups (p = 0.7). Further exclusions yielded 145 patients with gram positive infections for clinical outcomes evaluation (TDM, n = 66; CTRL, n = 75). The time to initial target trough was shorter in the TDM group (3 vs. 5 days, p < 0.001). Patients in the TDM group discharged from the hospital more rapidly, 7 vs. 14 days (Hazards Ratio (HR), 1.41; 95% Confidence Interval [CI] 1.08-1.83; p = 0.01), reached clinical stability faster, 4 vs. 8 days (HR, 1.51; 95% CI 1.08-2.11; p = 0.02), and had shorter courses of vancomycin, 4 vs. 7 days (HR, 1.5; 95% CI 1.15-1.95; p = 0.003). In the MRSA infection subset (TDM, n = 36; CTRL, n = 35), patients in the TDM group discharged from the hospital more rapidly, 7 vs. 16 days (HR, 1.89; 95% CI 1.08-3.3; p = 0.03), reached clinical stability faster, 4 vs. 6 days (HR, 2.69; 95% CI 1.27-5.7; p = 0.01), and had shorter courses of vancomycin, 5 vs. 8 days (HR, 2.52; 95% CI 1.38-4.6; p = 0.003). Attaining initial target troughs in <5 days versus ≥5 days was associated with improved clinical outcomes. All cause in-hospital mortality, and vancomycin treatment failure occurred at comparable rates between groups.

CONCLUSIONS

Interventions designed to decrease the time to reach initial target vancomycin troughs can improve clinical outcomes in gram positive infections, and in particular MRSA infections.

Innovative approaches to optimizing the delivery of vancomycin in individual patients

The delivery of personalized antimicrobial therapy is a critical component in the treatment of patients with invasive infections. Vancomycin, the drug of choice for infections due to methicillin-resistant Staphylococcus aureus, requires the use of therapeutic drug monitoring (TDM) for delivery of optimal therapy. Current guidance on vancomycin TDM includes the measurement of a trough concentration as a surrogate for achieving an AUC to minimum inhibitory concentration (MIC) by broth microdilution (AUC/MICBMD) ratio≥400. Although trough-only monitoring has been widely integrated into clinical practice, there is a high degree of inter-individual variability between a measured trough concentration and the actual AUC value. The therapeutic discordance between AUC and trough may lead to suboptimal outcomes among patients with infections due to less susceptible pathogens or unnecessarily increase the probability of acute kidney injury (AKI) in others. Given the potentially narrow vancomycin AUC range for optimal effect and minimal AKI, clinicians need a "real-time" system to predict accurately the AUC with limited pharmacokinetic (PK) sampling. This article reviews two innovative approaches for calculating the vancomycin AUC in clinical practice based on one or two drug concentrations. One such approach involves the use of Bayesian computer software programs to estimate the "true" vancomycin AUC value with minimal PK sampling and provide AUC-guided dosing recommendations at the bedside. An alternative involves use of two concentrations (peak and trough) and simple analytic equations to estimate AUC values. Both approaches provide considerable improvements over the current trough-only concentration monitoring method.

Vancomycin Nephrotoxicity

Vancomycin earned notoriety for its tendency to cause nephrotoxicity shortly after it was introduced into practice, though the impurities responsible for historically significant rates of nephrotoxicity are of minimal concern today. Increasing usage of vancomycin has provided evidence that the drug itself can be nephrotoxic, but the exact mechanism by which this occurs has not been determined. Various studies have identified risk factors associated with development of vancomycin-associated nephrotoxicity, including total daily dose > 4 grams, trough levels > 20 mg/L, therapy exceeding 6 days, concurrent use of other nephrotoxic agents, preexisting renal disease, obesity, hypotensive episodes, and increasing severity of illness. Preventative strategies beyond risk assessment and therapeutic drug monitoring have shown little promise. Most cases of nephrotoxicity are reversible with discontinuation of vancomycin, but permanent renal damage can occur. This article is intended to serve as a practical review of vancomycin-associated nephrotoxicity, including historical context, risk factors, and common methods to evaluate and define renal dysfunction.

Health economic evaluation of patients treated for nosocomial pneumonia caused by methicillin-resistant Staphylococcus aureus: secondary analysis of a multicenter randomized clinical trial of vancomycin and linezolid

PURPOSE

Results from studies comparing health care resource use (HCRU), costs of treatment, and cost-effectiveness of linezolid compared with vancomycin therapy in the treatment of hospitalized patients with methicillin-resistant Staphylococcus aureus (MRSA) nosocomial pneumonia are limited in the published literature. We therefore conducted an analysis to compare the HCRU, costs of treatment, and cost-effectiveness of linezolid compared with vancomycin in the treatment of hospitalized patients with MRSA nosocomial pneumonia using data from a Phase IV clinical trial. The economic effect of moderate to severe adverse events (MSAEs) and the development of renal failure were also evaluated.

METHODS

We performed a post hoc analysis of data from a Phase IV, double-blind, randomized, comparator-controlled, multicenter trial that compared linezolid and vancomycin treatment in patients with MRSA nosocomial pneumonia. HCRU and costs were compared based on treatment, development of MSAEs, and development of renal failure using data from the modified intent-to-treat population. Predictors of costs were evaluated using generalized linear models. A piggyback cost-effectiveness analysis was conducted to assess the incremental cost-effectiveness ratio of linezolid versus vancomycin, given the significantly higher clinical success of linezolid compared with vancomycin found in the trial.

FINDINGS

Overall, HCRU and costs were similar between the linezolid and vancomycin treatment groups; drug costs were significantly higher and dialysis costs significantly lower for linezolid- compared with vancomycin-treated patients. Total treatment costs were approximately $8000 higher (P = .046) for patients who developed renal failure compared with those who did not. Renal failure occurred more commonly in patients randomized to receive vancomycin (15%) compared with linezolid (4%; P < .001). Region, ventilator-associated pneumonia, clinical failure, and development of renal failure were associated with significantly higher total costs. The point estimate incremental cost-effectiveness ratio for linezolid compared with vancomycin was $16,516 per treatment success, with linezolid dominant in 24% and dominated in <2% of bootstrapped samples.

IMPLICATIONS

This phase 4 clinical trial conducted in patients with MRSA-confirmed nosocomial pneumonia reveals that linezolid- compared with vancomycin-treated patients had similar HCRU and total overall costs. Fewer patients developed renal failure during the study while taking linezolid compared with vancomycin, and patients with a documented MSAE or renal failure had increased HCRU and costs. In summary, linezolid may be a cost-effective treatment strategy in MRSA-confirmed nosocomial pneumonia.

Impact of acute kidney injury on mortality and medical costs in patients with meticillin-resistant Staphylococcus aureus bacteraemia: a retrospective, multicentre observational study

BACKGROUND

Despite the frequent occurrence of acute kidney injury (AKI) associated with meticillin-resistant Staphylococcus aureus (MRSA) infection during treatment, the adverse impact of renal injury on clinical and economic outcomes has not been evaluated.

AIM

To study the clinical and economic burdens of MRSA bacteraemia and the impact of AKI occurring during treatment on outcomes.

METHODS

Medical records of patients hospitalized for MRSA bacteraemia between March 2010 and February 2011 in eight hospitals in Korea were reviewed retrospectively to evaluate the risk factors for AKI and mortality. Direct medical costs per patient of MRSA bacteraemia during treatment were estimated from the medical resources consumed.

FINDINGS

In all, 335 patients were identified to have MRSA bacteraemia. AKI occurred in 135 patients (40.3%) during first-line antibiotic therapy. Independent risk factors for AKI were male sex, underlying renal disease, intra-abdominal and central venous catheter infection, and increase in Pitt bacteraemia score. Seventy-seven (23.0%) patients died during the study period. Underlying solid tumour, high Pitt bacteraemia score, and occurrence of AKI were independent risk factors for mortality. The mean total medical cost per MRSA patient was estimated as South Korean Won 5,435,361 (US$4,906), and occurrence of AKI and ICU admission were identified as independent predictors of increased direct medical costs. Compared with patients who retained their baseline renal function, patients with AKI had a 45% increase in medical costs.

CONCLUSIONS

Patients who developed AKI showed significantly higher mortality rate and greater direct medical costs compared with patients who retained baseline renal function.

Systematic review and meta-analysis of vancomycin-induced nephrotoxicity associated with dosing schedules that maintain troughs between 15 and 20 milligrams per liter

In an effort to maximize outcomes, recent expert guidelines recommend more-intensive vancomycin dosing schedules to maintain vancomycin troughs between 15 and 20 mg/liter. The widespread use of these more-intensive regimens has been associated with an increase in vancomycin-induced nephrotoxicity reports. The purpose of this systematic literature review is to determine the nephrotoxicity potential of maintaining higher troughs in clinical practice. All studies pertaining to vancomycin-induced nephrotoxicity between 1996 and April 2012 were identified from PubMed, Embase, Cochrane Controlled Trial Registry, and Medline databases and analyzed according to Cochrane guidelines. Of the initial 240 studies identified, 38 were reviewed, and 15 studies met the inclusion criteria. Overall, higher troughs (≥ 15 mg/liter) were associated with increased odds of nephrotoxicity (odds ratio [OR], 2.67; 95% confidence interval [CI], 1.95 to 3.65) relative to lower troughs of <15 mg/liter. The relationship between a trough of ≥ 15 mg/liter and nephrotoxicity persisted when the analysis was restricted to studies that examined only initial trough concentrations (OR, 3.12; 95% CI, 1.81 to 5.37). The relationship between troughs of ≥ 15 mg/liter and nephrotoxicity persisted after adjustment for covariates known to independently increase the risk of a nephrotoxicity event. An incremental increase in nephrotoxicity was also observed with longer durations of vancomycin administration. Vancomycin-induced nephrotoxicity was reversible in the majority of cases, with short-term dialysis required only in 3% of nephrotoxic episodes. The collective literature indicates that an exposure-nephrotoxicity relationship for vancomycin exists. The probability of a nephrotoxic event increased as a function of the trough concentration and duration of therapy.