Sustained improvement in vancomycin dosing and monitoring post-implementation of guidelines: Results of a three-year follow-up after a multifaceted intervention in an Australian teaching hospital

The Influence of a Therapeutic Drug Monitoring Service on Vancomycin-Associated Nephrotoxicity

Vancomycin's widespread use as the mainstay antibiotic against methicillin-resistant Staphylococcus aureus infections is complicated by its narrow therapeutic index. Therapeutic drug monitoring using area under the concentration-time curve (AUC)-guided dosing is recommended to optimize therapy and prevent vancomycin-associated nephrotoxicity (VAN). In 2018, a consultative therapeutic drug monitoring Advisory Service (the Service) was piloted at an Australian hospital to enable AUC-guided vancomycin dosing. This study sought to compare the incidence of VAN pre- and post-Service implementation. A 4-year retrospective observational study of intravenous vancomycin therapy (greater than 48 hours) in adults (aged 18 years or older), spanning 3 years before and 1-year after implementation of the Service was undertaken. Nephrotoxicity was defined as an increase in serum creatinine concentrations of 26.5 μmol/L or greater or 50% or more from baseline, on 2 or more consecutive days. Univariate analysis was performed to compare patients before and after implementation, and with and without VAN. Independent factors associated with VAN were identified using a multivariate model. In total, 971 courses of vancomycin therapy, administered to 781 patients, were included: 764 courses (603 patients) before implementation and 207 courses (163 patients) after implementation. The incidence of VAN decreased by 5% after Service implementation (15% before implementation vs 10% after implementation; P = .075). Independent factors associated with VAN were sepsis, heart failure, solid-organ transplant, concomitant piperacillin-tazobactam, and average vancomycin AUC during therapy. In conclusion, there was a nonsignificant trend toward a reduced incidence of VAN after the Service. Larger prospective studies are needed to confirm the efficacy of the Service.

Impact of pharmacist intervention in reducing vancomycin-associated acute kidney injury: A systematic review and meta-analysis

AIMS

The aim was to quantify the relationship between pharmacist intervention and vancomycin-associated acute kidney injury (AKI).

METHODS

Electronic databases were searched up to August 2020 for meta-analyses of cohort studies and/or randomized controlled trials. Studies that compared the incidence of AKI in patients between post- and prepharmacist intervention were investigated. The primary outcome was incidence of AKI. We also evaluated the influence of pharmacist intervention in risk factors of vancomycin-associated AKI.

RESULTS

The search strategy retrieved 1744 studies and 34 studies with 19 298 participants were included (22 published articles and 12 abstracts from conference proceedings). Compared with the preintervention group, the postintervention group patients had a significantly lower incidence of vancomycin-associated AKI: 7.3% for post- and 9.6% for preintervention (odds ratio [OR] 0.52, 95% confidence interval [CI]; 0.41, 0.67], P < .00001). The rate of attaining target concentration was significantly higher in the post- than preintervention group (OR 2.86, 95% CI [2.23, 3.67], P < .00001). The postintervention group significantly improved the percentage of serum creatinine laboratory tests than preintervention group (OR = 3.24, 95% CI 2.02, 5.19], P < .00001). Patients postintervention had markedly lower risk of mortality than preintervention patients (OR 0.47, 95% CI [0.31, 0.72], P = .0004).

CONCLUSION

Pharmacist intervention in vancomycin treatment significantly decreased the rate of vancomycin-associated AKI, while improving efficacy and reducing mortality. We speculate that this is because the pharmacist interventions optimized the rationality of vancomycin therapy, monitoring of vancomycin trough concentration and the monitoring of patients' renal function.

Impact of a monthly antimicrobial stewardship quality assurance tool for elevated vancomycin levels

Objective:

We sought to determine the value of an audit-and-feedback monitoring method in facilitating meaningful practice changes to improve vancomycin dosing and monitoring.

Design:

Retrospective, multicenter, before-and-after implementation observational quality assurance initiative.

Setting:

The study was conducted in 7 not-for-profit, acute-care hospitals within a health system in southern Florida.

Methods:

The preimplementation period (September 1, 2019, through August 31, 2020) was compared to the postimplementation period (September 1, 2020, through May 31, 2022). All vancomycin serum-level results were screened for inclusion. The primary end point was the rate of fallout, defined as vancomycin serum level ≥25 µg/mL with acute kidney injury (AKI) and off-protocol dosing and monitoring. Secondary end points included the rate of fallout with respect to AKI severity, rate of vancomycin serum levels ≥25 µg/mL, and average number of serum-level evaluations per unique vancomycin patient.

Results:

In total, 27,611 vancomycin levels were analyzed from 13,910 unique patients. There were 2,209 vancomycin serum levels ≥25 µg/mL (8%) among 1,652 unique patients (11.9%). AKI was identified in 379 unique patients (23%) with a vancomycin levels ≥25 µg/mL. In total, 60 fallouts (35.2%) occurred in the 12-month preimplementation period (∼5 per month) and 41 fallouts (19.6%) occurred in the 21-month postimplementation period (∼2 per month; P = .0006). Failure was the most common AKI severity in both periods (risk: 35% vs 24.3%, P = .25; injury: 28.3% vs 19.5%, P = .30; failure: 36.7% vs 56%, P = .053). Overall, the number of evaluations of vancomycin serum levels per unique patient remained consistent throughout both periods (2 vs 2; P = .53).

Conclusions:

Implementation of a monthly quality assurance tool for elevated outlier vancomycin levels can improve dosing and monitoring practices resulting in enhanced patient safety.

Optimization of the vancomycin administration regimen by clinical pharmacists based on a population pharmacokinetics model: a prospective interventional study

In vancomycin treatment, the rates of correct blood sampling and initial trough concentrations within the target range are very low. Studies of interventions by clinical pharmacists based on population pharmacokinetics (PPK) models are limited. This study aimed to evaluate the intervention effect of clinical pharmacist-mediated optimization of the vancomycin administration regimen based on a PPK model. Retrospectively enrolled patients constituted the control group, and prospectively enrolled patients constituted the intervention group. The vancomycin administration regimen, trough concentration, pharmacokinetic parameters, and clinical outcomes of the two groups were compared. The control and intervention groups comprised 236 and 138 patients, respectively. Compared with those in the control group, the therapeutic drug monitoring (TDM) and correct TDM sampling time rates in the intervention group were significantly higher (76.92% vs. 43.59%; 63.9% vs. 39.0%, both p < 0.001). The rates of an initial trough concentration within 10-20 mg/L and an adjusted regimen were also significantly higher in the intervention group (55.80% vs. 30.51%, 71.95% vs. 39.18%, both p < 0.001). The rate of an area under the curve (AUC) within 400-650 mg·h/L was higher in the intervention group than in the control group (52.7% vs. 36.6%, p < 0.001). The eradication rates of Gram-positive bacteria were 91.4% in the intervention group and 81.3% in the control group (p = 0.049). Eight patients developed acute kidney injury (AKI) in the control group; however, no AKI occurred in the intervention group (p = 0.029). Intervention by clinical pharmacists can increase the rate of correct sampling time. Using the PPK model combined with Bayesian estimation, clinical pharmacists can greatly increase the trough concentration and AUCs within the target range, especially for adjusted regimens. Higher PK/PD target rates resulted in better Gram-positive bacterial eradication and reduced renal toxicity of vancomycin.

Effectiveness of a vancomycin dosing protocol guided by area under the concentration-time curve to minimal inhibitory concentration (AUC/MIC) with multidisciplinary team support to improve hospital-wide adherence to a vancomycin dosing protocol: A pilot study

BACKGROUND

Limited data are available on the implementation of an area under the concentration-time curve (AUC)-based dosing protocol with multidisciplinary team (MT) support to improve adherence with vancomycin dosing protocol.

OBJECTIVE

To evaluate the effectiveness of an AUC-based dosing protocol with MT support intervention with adherence to a hospital-wide vancomycin dosing protocol at Thammasat University Hospital.

METHOD

We conducted a quasi-experimental study in patients who were prescribed intravenous vancomycin. The study was divided into 2 periods; (1) the preintervention period when the vancomycin dosing protocol was already applied in routine practice and (2) the post-intervention period when the implementation of an AUC-based dosing protocol with MT support was added to the existing vancomycin dosing protocol. The primary outcome was the rate of adherence, and the secondary outcomes included acute kidney injury events, vancomycin-related adverse events, and 30-day mortality rate.

RESULTS

In total, 240 patients were enrolled. The most common infections were skin and soft-tissue infections (24.6%) and bacteremia (24.6%). The most common pathogens were coagulase-negative staphylococci (19.6%) and Enterococcus spp (15.4%). Adherence with the vancomycin dosing protocol was significantly higher in the postintervention period (90.8% vs 55%; P ≤ .001). By multivariate analysis, an AUC-based dosing protocol with MT support was the sole predictor for adherence with the vancomycin dosing protocol (adjusted odds ratio, 10.31; 95% confidence interval, 4.54-23.45; P ≤ .001). The 30-day mortality rate was significantly lower during the postintervention period (8.3% vs 20%; P = .015).

CONCLUSIONS

AUC-based dosing protocol with MT support significantly improved adherence with vancomycin dosing protocol and was associated with a lower 30-day mortality rate.

Development and evaluation of a national gentamicin and vancomycin quality improvement programme

BACKGROUND

Scottish Antimicrobial Prescribing Group (SAPG) recommendations to reduce broad-spectrum antimicrobial use led to an increase in gentamicin and vancomycin prescribing. In 2009, SAPG introduced national guidance to standardize dosage regimens, reduce calculation errors and improve the monitoring of these antibiotics. Studies conducted in 2010 and 2011 identified limitations in guideline implementation.

OBJECTIVES

To develop, implement and assess the long-term impact of quality improvement (QI) resources to support gentamicin and vancomycin prescribing, administration and monitoring.

METHODS

New resources, comprising revised guidelines, online and mobile app dose calculators, educational material and specialized prescribing and monitoring charts were developed in collaboration with antimicrobial specialists and implemented throughout Scotland during 2013-16. An online survey in 2017 evaluated the use of these resources and a before (2011) and after (2018) point prevalence study assessed their impact.

RESULTS

All 12 boards who responded to the survey (80%) were using the guidance, electronic calculators and gentamicin prescription chart; 8 used a vancomycin chart. The percentage of patients who received the recommended gentamicin dose increased from 44% to 89% (OR 10.99, 95% CI = 6.37-18.95) between 2011 and 2018. For vancomycin, the correct loading dose increased from 50% to 85% (OR = 5.69, CI = 2.76-11.71) and the correct maintenance dose from 55% to 90% (OR = 7.17, CI = 3.01-17.07).

CONCLUSIONS

This study demonstrated improvements in the national prescribing of gentamicin and vancomycin through the development and coordinated implementation of a range of QI resources and engagement with local and national multidisciplinary teams.

Vancomycin dosing and therapeutic drug monitoring practices: guidelines versus real-life

Background Correct dosing and therapeutic drug monitoring (TDM) practices are essential when aiming for optimal vancomycin treatment. Objective To assess target attainment after initial dosing and dose adjustments, and to determine compliance to dosing and TDM guidelines. Setting Tertiary care university hospital in Belgium. Method A chart review was performed in 150 patients, ranging from preterm infants to adults, treated intravenously with vancomycin. Patient characteristics, dosing and TDM data were compared to evidence-based hospital guidelines. Main outcome measures Target attainment of vancomycin after initial dosing and dose adjustments. Results Subtherapeutic concentrations were measured in 68% of adults, in 76% of children and in 52% of neonates after treatment initiation. Multiple dose adaptations (median 2, Q1 1-Q3 2) were required for target attainment, whilst more than 20% of children and neonates never reached targeted concentrations. Regarding compliance to the hospital guideline, some points of improvement were identified: omitted dose adjustment in adults with decreased renal function (53%), delayed sampling (16% in adults, 31% in children) and redundant sampling (34% of all samples in adults, 12% in children, 13% in neonates). Conclusion Target attainment for vancomycin with current dosing regimens and TDM is poor in all age groups. Besides, human factors should not be ignored when aiming for optimal treatment. This study reflects an ongoing challenge in clinical practice and highlights the need for optimization of vancomycin dosing strategies and improvement of awareness of all health care professionals involved.

Are vancomycin dosing guidelines followed? A mixed methods study of vancomycin prescribing practices

AIMS

Despite the availability of international consensus guidelines, vancomycin dosing and therapeutic drug monitoring (TDM) remain suboptimal. This study aimed to assess concordance of vancomycin dosing and TDM with institutional guidelines and to identify factors taken into consideration by clinicians when prescribing vancomycin.

METHODS

A retrospective audit of 163 patients receiving vancomycin therapy (≥48 hours) was undertaken. Data collected included patient characteristics, dosing history and plasma vancomycin and creatinine concentrations. Concordance of dosing and TDM with institutional guidelines was evaluated. Semi-structured interviews, including simulated prescribing scenarios, were undertaken with prescribers (n = 17) and transcripts analysed.

RESULTS

Plasma vancomycin concentrations (n = 1043) were collected during 179 courses of therapy. Only 24% of courses commenced with a loading dose with 72% lower than recommended. The initial maintenance dose was concordant in 42% of courses with 34% lower than recommended. Only 14% of TDM samples were trough vancomycin concentrations. Dose was not adjusted for 60% (21/35) of subtherapeutic and 43% (18/42) of supratherapeutic trough vancomycin concentrations, respectively. Interview participants reported that patient characteristics (including renal function), vancomycin concentrations, guidelines and expert advice influenced vancomycin prescribing decisions. Despite referring to guidelines when completing simulated prescribing scenarios, only 37% of prescribing decisions aligned with guideline recommendations.

CONCLUSION

Poor compliance with institutional vancomycin guidelines was observed, despite prescriber awareness of available guidelines. Multifaceted strategies to support prescriber decision-making are required to improve vancomycin dosing and monitoring.

Vancomycin: Audit of American guideline-based intermittent dose administration with focus on overweight patients

AIMS

Vancomycin dosing and monitoring recommendations are poorly adhered to in many institutions internationally, with concerns of treatment failure and propelling antibiotic resistance. The primary aim of this study was to audit the rate of adherence to American guidelines, with particular interest in loading dose administration. The secondary aims were (i) to determine whether or not guideline adherence results in therapeutic concentrations across body mass index (BMI) groups and (ii) to determine whether or not this was in turn associated with morbidity and hospital mortality.

METHOD

Data were collected in a single tertiary hospital on all patients who had two or more serum vancomycin concentrations measured.

RESULT

In total, 107 patients met the inclusion criteria. Overall, 38.3% of patients were commenced on guideline adherent vancomycin doses, and 28.3% of overweight patients received an adherent first dose compared to 51.1% of non-overweight people (difference 23%, 95% CI 4% to 41%, P = 0.024). Overweight patients were more frequently underdosed compared to non-overweight patients (P = 0.039). The frequency and proportion of underdosing increased with BMI. Overweight patients spent a smaller fraction of their course within the therapeutic range, although the difference was not statistically significant (difference 7.7%; 95% CI 4% to 19.4%; P = 0.195). The overweight group had longer hospital length of stay (LOS), higher mortality and more treatment failures.

CONCLUSION

Adherence to guideline-based prescription is poor, particularly in overweight patients. Patients who are initially underdosed have fewer therapeutic vancomycin days, regardless of BMI. Overweight patients have increased hospital LOS, hospital mortality and treatment failure.

Attention to age: similar dosing regimens lead to different vancomycin levels among older and younger patients

BACKGROUND

little is known on the clinical implications of vancomycin trough levels among older patients.

OBJECTIVE

to evaluate the association between vancomycin levels and outcomes among older versus younger patients.

DESIGN

retrospective study.

SUBJECTS

patients aged 18-64 and ≥65 years treated with vancomycin for documented methicillin resistant Staphylococcus aureus (MRSA) infections.

METHODS

we compared the effectiveness and toxicity of vancomycin according to trough levels in older versus younger patients. Subgroup analysis of patients with glomerular filtration rate (GFR) > 60 ml/min/1.73 m2 was performed.

RESULTS

we included 181 patients aged ≥65 years and 104 younger patients. Mean age in the older group was 76.9 ± 8 years versus 50.9 ± 12.4 in the younger group. Vancomycin trough levels and 24-hours area under the curve to minimal inhibitory concentrations (AUC/MIC) were significantly higher in older patients who were also significantly more likely to achieve trough levels of ≥15 mg/l within 4 days, (98/181 (54.1%) vs. 38/104 (36.5%) in younger patients, P = 0.004). Results were similar among patients with GFR > 60. Thirty-day mortality was significantly higher in older (74/181, 40.9% vs. 13/104, 12.5%, respectively, P < 0.001). There was no association between vancomycin trough levels and mortality among older patients. No significant differences were demonstrated in clinical or microbiological success or nephrotoxicity.

CONCLUSIONS

applying uniform dosing recommendations across age groups among adults with MRSA infections results in higher vancomycin levels and AUC/MIC in older versus younger patients. Yet, mortality rates remain higher among older adults. Prospective studies are needed to define the optimal approach for using this drug in older patients.

Automating Vancomycin Monitoring to Improve Patient Safety

INTRODUCTION

Intravenous vancomycin is a frequently used antibiotic and a common cause of medication-related harm because of its narrow therapeutic range. Improving monitoring of drug levels with automation in the electronic health record (EHR) may decrease this harm.

METHODS

After examining the existing state of vancomycin ordering, administration, and monitoring, an automated process was created in the EHR that, on initiation of a new vancomycin order, automatically ordered a vancomycin trough level 30 minutes before the fourth dose. In addition, a nursing alert was integrated into the bar coding medication administration process that, if no trough level had been drawn by the time of the administration of the fourth dose, prompted the nurse to draw a trough level. Data from a three-month, post-implementation period was compared to data from a preceding three-month period.

RESULTS

The frequency of trough levels drawn between the third and fourth dose increased from 58.6% to 75.8% (p < 0.01). However, the percentage of trough levels drawn within one hour of the fourth dose remained unchanged, possibly because nursing staff waited for the result of the level prior to administering the next dose of vancomycin. A minority of patients in both groups had trough levels that were in range (difference between groups, p = 0.46).

CONCLUSION

Automation of vancomycin monitoring was associated with improvement in the frequency of monitoring and only delayed medication dosing by six minutes. Because vancomycin is high risk, this type of process should be broadly implemented, and outcomes should be assessed to identify unexpected outcomes and necessary further refinements.

Interventions targeting the prescribing and monitoring of vancomycin for hospitalized patients: a systematic review with meta-analysis

Purpose

Vancomycin prescribing requires individualized dosing and monitoring to ensure efficacy, limit toxicity, and minimize resistance. Although there are nationally endorsed guidelines from several countries addressing the complexities of vancomycin dosing and monitoring, there is limited consideration of how to implement these recommendations effectively.

Methods

We conducted a systematic search of multiple databases to identify relevant comparative studies describing the impact of interventions of educational meetings, implementation of guidelines, and dissemination of educational material on vancomycin dosing, monitoring, and nephrotoxicity. Effect size was assessed using ORs and pooled data analyzed using forest plots to provide overall effect measures.

Results

Six studies were included. All studies included educational meetings. Two studies used implementation of guidance, educational meetings, and dissemination of educational materials, one used guidance and educational meetings, one educational meetings and dissemination of educational materials, and two used educational meetings solely. Effect sizes for individual studies were more likely to be significant for multifaceted interventions. In meta-analysis, the overall effect of interventions on outcome measures of vancomycin dosing was OR 2.50 (95% CI 1.29–4.84); P< 0.01. A higher proportion of sampling at steady-state concentration was seen following intervention (OR 1.95, 95% CI 1.26–3.02; P<0.01). Interventions had no effect on appropriate timing of trough sample (OR 2.02, 95% CI 0.72–5.72; P=0.18), attaining target concentration in patients (OR 1.50, 95% CI 0.49–4.63; P=0.48, or nephrotoxicity (OR 0.75, 95% CI 0.42–1.34; P=0.33).

Conclusion

Multifaceted interventions are effective overall in improving the complex task of dosing vancomycin, as well as some vancomycin-monitoring outcome measures. However, the resulting impact of these interventions on efficacy and toxicity requires further investigation. These findings may be helpful to those charged with designing implementation strategies for vancomycin guidelines or complex prescribing processes in hospitals.