Top Guns: The "Maverick" and "Goose" of Empiric Therapy

Vancomycin nephrotoxicity: A comprehensive clinico-pathological study

INTRODUCTION

Vancomycin, a commonly prescribed antibiotic particularly in the setting of multi-drug resistant infections, is limited by its nephrotoxicity. Despite its common occurrence, much remains unknown on the clinicopathologic profile as well as the pathogenesis of vancomycin nephrotoxicity. Clinical studies included patients often with severe comorbidities and concomitant polypharmacy confounding the causal pathogenesis. Animal models cannot recapitulate this complex clinical situation. Kidney biopsy was not commonly performed.

METHODS

To address this limitation, we studied 36 patients who had renal biopsies for acute kidney injury (AKI) for suspicion of vancomycin nephrotoxicity. Detailed renal biopsy evaluation, meticulous evaluation of clinical profiles, and up-to-date follow-up allowed for a diagnostic categorization of vancomycin nephrotoxicity (VNT) in 25 patients and absence of vancomycin nephrotoxicity (NO-VNT) in 11 patients. For careful comparison of these two groups, we proceeded to compile a clinicopathologic and morphologic profiles characteristic for each group.

RESULTS

Patients with VNT had a characteristic clinical profile including a common clinical background, a high serum trough level of vancomycin, a rapidly developed and severe acute kidney injury, and a recovery of renal function often shortly after discontinuation of vancomycin. This clinical course was correlated with characteristic renal biopsy findings including acute tubulointerstitial nephritis of allergic type, frequent granulomatous inflammation, concomitant and pronounced acute tubular necrosis of nephrotoxic type, and vancomycin casts, in the absence of significant tubular atrophy and interstitial fibrosis. This clinico-pathologic profile was different from that of patients with NO-VNT, highlighting its role in the diagnosis, management and pathogenetic exploration of vancomycin nephrotoxicity.

CONCLUSION

Vancomycin nephrotoxicity has a distinctive morphologic and clinical profile, which should facilitate diagnosis, guide treatment and prognostication, and confer pathogenetic insights.

Vancomycin-Associated Acute Kidney Injury: A Narrative Review from Pathophysiology to Clinical Application

Vancomycin is the most frequently used antibiotic, accounting for up to 35% of hospitalized patients with infection, because of its optimal bactericidal effectiveness and relatively low price. Vancomycin-associated AKI (VA-AKI) is a clinically relevant but not yet clearly understood entity in critically ill patients. The current review comprehensively summarizes the pathophysiological mechanisms of, biomarkers for, preventive strategies for, and some crucial issues with VA-AKI. The pathological manifestations of VA-AKI include acute tubular necrosis, acute tubulointerstitial nephritis (ATIN), and intratubular crystal obstruction. The proposed pathological mechanisms of VA-AKI include oxidative stress and allergic reactions induced by vancomycin and vancomycin-associated tubular casts. Concomitant administration with other nephrotoxic antibiotics, such as piperacillin–tazobactam, high vancomycin doses, and intermittent infusion strategies compared to the continuous infusion are associated with a higher risk of VA-AKI. Several biomarkers could be applied to predict and diagnose VA-AKI. To date, no promising therapy is available. Oral steroids could be considered for patients with ATIN, whereas hemodialysis might be applied to remove vancomycin from the patient. In the future, disclosing more promising biomarkers that could precisely identify populations susceptible to VA-AKI and detect VA-AKI occurrence early on, and developing pharmacological agents that could prevent or treat VA-AKI, are the keys to improve the prognoses of patients with severe infection who probably need vancomycin therapy.

Comparative Prevalence of Acute Kidney Injury in Chinese Patients Receiving Vancomycin with Concurrent β-Lactam Antibiotics: A Retrospective Cohort Study

PURPOSE

The combination of vancomycin and piperacillin/tazobactam (VAN + PTZ) provides a broad spectrum of activity against multiple pathogens. However, a major issue in previous research concerned significant nephrotoxicity associated with this drug combination, and most studies have been conducted in American and European countries, with no similar data available from China. Therefore, this study evaluated the nephrotoxic effects of VAN + PTZ in a large-scale Chinese cohort to determine the prevalence of acute kidney injury (AKI) in this population by comparing PTZ and vancomycin monotherapies and the combined use of vancomycin and β-lactam antibiotics.

METHODS

This retrospective cohort study identified adult patients who received vancomycin either as monotherapy or in combination with PTZ or carbapenem (VAN + CAR) for at least 48 hours at Jiangsu Province Hospital from January 1, 2017, to December 31, 2018. Patients were also evaluated for the development of AKI, defined according to the Kidney Disease Improving Global Outcome criteria. Duration of vancomycin exposure, steady-state trough vancomycin concentrations, and other risk factors for AKI were assessed. A Bayesian network meta-analysis was conducted to validate our results and comparatively evaluate the nephrotoxicity of β-lactam antibiotics in combination with vancomycin.

FINDINGS

In all, 752 patients were included in the present study. The prevalence of AKI was higher in the VAN + PTZ group than in the VAN and VAN + CAR groups (15.2% vs 4.0% and 6.0%, respectively). After adjustment for confounding factors, VAN + PTZ was still related to AKI (odds ratio [OR] = 4.37; 95% CI, 1.65-11.59; P = 0.003). The network meta-analysis indicated that VAN + PTZ was associated with a significantly higher risk for AKI than was VAN (OR = 3.23; 95% CI, 2.50-4.35), PTZ (OR = 2.86; 95% CI, 1.92-4.12), VAN + cefepime (FEP) (OR = 2.37; 95% CI, 1.80-3.19), or VAN + CAR (OR = 2.28; 95% CI, 1.64-3.21). However, there was no significant difference with respect to AKI prevalence among the VAN, PTZ, VAN + FEP, and VAN + CAR groups.

IMPLICATIONS

The prevalence of AKI was higher with VAN + PTZ therapy than with VAN or PTZ monotherapy or with the concurrent use of VAN and FEP or CAR in our study. Clinicians should adequately assess renal function and consider this differential risk for nephrotoxicity when choosing empiric antibiotics in hospitalized patients to minimize the rates of AKI.

Tolerance and microbiological efficacy of cefepime or piperacillin/tazobactam in combination with vancomycin as empirical antimicrobial therapy of prosthetic joint infection: a propensity-matched cohort study

BACKGROUND

The use of piperacillin/tazobactam with vancomycin as empirical antimicrobial therapy (EAT) for prosthetic joint infection (PJI) has been associated with an increased risk of acute kidney injury (AKI), leading us to propose cefepime as an alternative since 2017 in our reference centre.

OBJECTIVES

To compare microbiological efficacy and tolerance of these two EAT strategies.

METHODS

All adult patients with PJI empirically treated with vancomycin+cefepime (n = 89) were enrolled in a prospective observational study and matched with vancomycin+piperacillin/tazobactam-treated historical controls (n = 89) according to a propensity score including age, baseline renal function and concomitant use of other nephrotoxic agents. The two groups were compared using Kaplan-Meier curve analysis, and non-parametric tests regarding the proportion of efficacious empirical regimen and the incidence of empirical therapy-related adverse events (AE).

RESULTS

Among 146 (82.0%) documented infections, the EAT was considered efficacious in 77 (98.7%) and 65 (98.5%) of the piperacillin/tazobactam- and cefepime-treated patients, respectively (P = 1.000). The rate of AE, particularly AKI, was significantly higher in the vancomycin+piperacillin/tazobactam group [n = 27 (30.3%) for all AE and 23 (25.8%) for AKI] compared with the vancomycin+cefepime [n = 13 (14.6%) and 6 (6.7%)] group (P = 0.019 and <0.001, respectively), leading to premature EAT discontinuation in 20 (22.5%) and 5 (5.6%) patients (P = 0.002). The two groups were not significantly different regarding their comorbidities, and AKI incidence was not related to vancomycin plasma overexposure.

CONCLUSIONS

Based on the susceptibility profile of bacterial isolates from included patients, microbiological efficacy of both strategies was expected to be similar, but vancomycin + cefepime was associated with a significantly lower incidence of AKI.

Lack of synergistic nephrotoxicity between vancomycin and piperacillin/tazobactam in a rat model and a confirmatory cellular model

BACKGROUND

Vancomycin and piperacillin/tazobactam are reported in clinical studies to increase acute kidney injury (AKI). However, no clinical study has demonstrated synergistic toxicity, only that serum creatinine increases.

OBJECTIVES

To clarify the potential for synergistic toxicity between vancomycin, piperacillin/tazobactam and vancomycin + piperacillin/tazobactam treatments by quantifying kidney injury in a translational rat model of AKI and using cell studies.

METHODS

(i) Male Sprague-Dawley rats (n = 32) received saline, vancomycin 150 mg/kg/day intravenously, piperacillin/tazobactam 1400 mg/kg/day intraperitoneally or vancomycin + piperacillin/tazobactam for 3 days. Urinary biomarkers and histopathology were analysed. (ii) Cellular injury was assessed in NRK-52E cells using alamarBlue®.

RESULTS

Urinary output increased from Day -1 to Day 1 with vancomycin but only after Day 2 for vancomycin + piperacillin/tazobactam-treated rats. Plasma creatinine was elevated from baseline with vancomycin by Day 2 and only by Day 4 for vancomycin + piperacillin/tazobactam. Urinary KIM-1 and clusterin were increased with vancomycin from Day 1 versus controls (P < 0.001) and only on Day 3 with vancomycin + piperacillin/tazobactam (P < 0.001, KIM-1; P < 0.05, clusterin). The histopathology injury score was elevated only in the vancomycin group when compared with piperacillin/tazobactam as a control (P = 0.04) and generally not so with vancomycin + piperacillin/tazobactam. In NRK-52E cells, vancomycin induced cell death with high doses (IC50 48.76 mg/mL) but piperacillin/tazobactam did not, and vancomycin + piperacillin/tazobactam was similar to vancomycin.

CONCLUSIONS

All groups treated with vancomycin demonstrated AKI; however, vancomycin + piperacillin/tazobactam was not worse than vancomycin. Histopathology suggested that piperacillin/tazobactam did not worsen vancomycin-induced AKI and may even be protective.

Nephrotoxicity from Vancomycin Combined with Piperacillin-Tazobactam: A Comprehensive Review

BACKGROUND

Recent studies have identified the combination of vancomycin with piperacillin-tazobactam (VPT) to be associated with increased nephrotoxicity. Multiple, large cohort studies have found this widely used combination to have a higher risk of nephrotoxicity than other regimens in a variety of populations.

SUMMARY

This review summarizes the epidemiology and clinical features of VPT-associated acute kidney injury (AKI). Potential mechanisms involved in the pathogenesis of this phenomenon are also discussed. Key Message: VPT-associated nephrotoxicity is a recently recognized clinical entity. Clinical strategies to minimize the risk of toxicity in this setting include antimicrobial stewardship, monitoring of kidney function, and emerging data supporting the potential role for novel biomarkers in predicting and managing AKI.

Risk of Acute Kidney Injury in Combat-Injured Patients Associated With Concomitant Vancomycin and Extended-Spectrum β-Lactam Antibiotic Use

BACKGROUND

Multidrug-resistant infections complicating combat-related trauma necessitate the use of broad-spectrum antimicrobials. Recent literature posits an association between vancomycin (VANC) and piperacillin-tazobactam (VPT) combination therapy and acute kidney injury (AKI). We examined whether therapy with VPT was associated with an increased risk of AKI compared to VANC and other broad-spectrum β-lactam antibiotics (VBL) following combat-related injuries.

METHODS

Patients within the Trauma Infectious Disease Outcomes Study (TIDOS) who received ≥48 hours concomitant VPT or VBL started within 24 hours of each other were assessed. Exclusion criteria were receipt of renal replacement therapy and baseline creatinine >1.5 mg/dL. Acute kidney injury was defined by meeting any of the Risk, Injury, Failure, Loss, End Stage Renal Disease (RIFLE), AKIN, or VANC consensus guidelines criteria 3 to 7 days after therapy initiation. Variables significantly associated with AKI were used in inverse probability treatment weighting to perform univariate and subsequent logistic regression multivariate modeling to determine significant risk factors for AKI.

RESULTS

Sixty-one patients who received VPT and 207 who received VBL were included. Both groups had a median age of 24 years and initial median creatinine of 0.7 mg/dL. The VBL patients were more likely to have sustained blast injuries (P = .001) and received nephrotoxic agents (amphotericin [P = .002] and aminoglycosides [P < .001]). In the VBL group, AKI incidence was 9.7% compared to 13.1% in the VPT group (P = .438). Multivariate analysis identified a relative risk of 1.727 (95% CI: 1.027-2.765) for AKI associated with VPT exposure. Acute kidney injury severity generally met RIFLE Risk criteria and was 1 day in duration. Only 1 patient had persistent renal dysfunction 30 days after therapy completion.

CONCLUSION

In this young and previously healthy, severely ill combat-injured population, VPT was associated with nearly twice the risk of AKI compared to VBL. Nevertheless, AKI was of low severity, short duration, and had high rates of renal recovery.

Acute kidney injury following the concurrent administration of antipseudomonal β-lactams and vancomycin: a network meta-analysis

BACKGROUND

Acute kidney injury is a major complication of vancomycin treatment, especially when it is co-administered with other nephrotoxins.

OBJECTIVES

This meta-analysis aims to comparatively assess the nephrotoxicity of antipseudomonal β-lactams when combined with vancomycin.

DATA SOURCES

Medline, Scopus, CENTRAL and Clinicaltrials.gov databases were systematically searched from inception through 20 August 2019.

STUDY ELIGIBILITY CRITERIA

Studies evaluating acute kidney injury risk following the concurrent use of antipseudomonal β-lactams and vancomycin were selected.

PARTICIPANTS

Adult and paediatric patients treated in hospital or intensive care unit.

INTERVENTIONS

Administration of vancomycin combined with any antipseudomonal β-lactam.

METHODS

Acute kidney injury incidence was defined as the primary outcome. Secondary outcomes included severity, onset, duration, need of renal replacement therapy, length of hospitalization and mortality. Quality of evidence was assessed using the ROBINS-I tool and the Confidence In Network Meta-Analysis approach.

RESULTS

Forty-seven cohort studies were included, with a total of 56 984 patients. In the adult population, the combination of piperacillin-tazobactam and vancomycin resulted in significantly higher nephrotoxicity rates than vancomycin monotherapy (odds ratio (OR) 2.05, 95% confidence intervals (CI) 1.17-3.46) and its concurrent use with meropenem (OR 1.84, 95% CI 1.02-3.10) or cefepime (OR 1.80, 95% CI 1.13-2.77). In paediatric patients, acute kidney injury was significantly higher with vancomycin plus piperacillin-tazobactam than vancomycin alone (OR 4.18, 95% CI 1.01-17.29) or vancomycin plus cefepime OR 3.71, 95% CI 1.08-11.24). No significant differences were estimated for the secondary outcomes. Credibility of outcomes was judged as moderate, mainly due to imprecision and inter-study heterogeneity.

CONCLUSIONS

The combination of vancomycin and piperacillin-tazobactam is associated with higher acute kidney injury rates than its parallel use with meropenem or cefepime. Current evidence is exclusively observational and is limited by inter-study heterogeneity. Randomized controlled trials are needed to verify these results and define preventive strategies to minimize nephrotoxicity risk.

Acute Kidney Injury in Pediatric Patients Treated with Vancomycin and Piperacillin-Tazobactam Versus Vancomycin and Cefotaxime: A Single-center Study

Background

Previous literature showed a higher incidence of acute kidney injury (AKI) in pediatric patients using vancomycin + piperacillin-tazobactam compared to cefepime + vancomycin. Our aim was to compare the incidence of developing AKI during the use of vancomycin + cefotaxime with that during the use of vancomycin + piperacillin-tazobactam in pediatric patients.

Methods

This was a retrospective, matched cohort study that used electronic records from May 1, 2015 through April 30, 2018 for all patients aged less than 16 years who received intravenous (IV) vancomycin + piperacillin-tazobactam or cefotaxime + vancomycin for at least 72 hours. AKI was defined by Kidney Disease Improving Global Outcomes (KDIGO) guidelines. Each patient from the vancomycin + piperacillin-tazobactam group was matched 1:1 with those in the vancomycin + cefotaxime group according to their age, chronic disease, gender, and the number of concomitant nephrotoxic agents. A total of 64 cases were included. Statistical analysis was performed using descriptive statistics and binary logistic regression.

Results

AKI developed in 10 of 32 patients (31.25%) who were using vancomycin + piperacillin-tazobactam. On the other hand, 13 of 32 patients (40.62%) were using cefotaxime + vancomycin (p = 0.047). Of the 10 patients who were on vancomycin + piperacillin-tazobactam regimen, 80% developed AKI Stage I. Of the 13 patients who were using cefotaxime + vancomycin, 46% developed AKI Stage II, although no statistical significance was noted in all stages. 

Conclusion

Our study showed that patients treated with cefotaxime and vancomycin showed a higher incidence of AKI than patients treated with vancomycin and piperacillin-tazobactam, although the study showed no statistical significance.

Acute Kidney Injury in Non-Intensive Care and Intensive Care Patients Treated with Vancomycin and Piperacillin-Tazobactam

BACKGROUND

We investigated the incidence of acute kidney injury (AKI) and risk factors associated with vancomycin (VAN) and piperacillin-tazobactam (TZP) combination therapy in non-intensive care unit (ICU) and ICU settings.

METHODS

In this single-center retrospective cohort study, adults who received VAN for ≥48 h during the period from 1 January 2016 through 31 December 2017 were included. The primary endpoint was incidence of AKI.

RESULTS

Data from 593 adults were analyzed. The incidence of AKI was 10.6% overall, 8.0% in the non-TZP group, and 19.8% in the TZP group. In univariate analysis, the odds ratio (OR) for AKI was higher in the TZP group than in the non-TZP group (2.84, 95% CI = 1.64-4.90). In both the non-ICU and ICU settings, the OR for AKI was higher in the TZP group than in the non-TZP group (non-ICU: OR = 3.04, 95% CI = 1.52-6.09; ICU: OR = 2.51, 95% CI = 1.03-6.08). Furthermore, in propensity score analysis, the OR for AKI was higher in the TZP group than in the non-TZP group (OR = 2.81, 95% CI = 1.52-5.17). In both the non-ICU and ICU settings, the OR for AKI was higher in the TZP group than in the non-TZP group (non-ICU: OR = 2.57, 95% CI = 1.17-5.64; ICU: OR = 3.51, 95% CI = 1.05-11.6).

CONCLUSIONS

Combined use of TZP in patients receiving VAN increased AKI incidence in non-ICU and ICU settings.

Incidence of Acute Kidney Injury in Critically Ill Patients Receiving Vancomycin with Concomitant Piperacillin-Tazobactam, Cefepime, or Meropenem

Critically ill patients are frequently treated with empirical antibiotic therapy, including vancomycin and β-lactams. Recent evidence suggests an increased risk of acute kidney injury (AKI) in patients who received a combination of vancomycin and piperacillin-tazobactam (VPT) compared with patients who received vancomycin alone or vancomycin in combination with cefepime (VC) or meropenem (VM), but most studies were conducted predominately in the non-critically ill population. A retrospective cohort study that included 2,492 patients was conducted in the intensive care units of a large university hospital with the primary outcome being the development of any AKI. The rates of any AKI, as defined by the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines, were 39.3% for VPT patients, 24.2% for VC patients, and 23.5% for VM patients (P < 0.0001 for both comparisons). Similarly, the incidences of stage 2 and stage 3 AKI were also significantly higher for VPT patients than for the patients in the other groups. The rates of stage 2 and stage 3 AKI, respectively, were 15% and 6.6% for VPT patients, 5.8% and 1.8% for VC patients, and 6.6% and 1.3% for VM patients (P < 0.0001 for both comparisons). In multivariate analysis, the use of vancomycin in combination with piperacillin-tazobactam was found to be an independent predictor of AKI (odds ratio [OR], 2.161; 95% confidence interval [CI], 1.620 to 2.883). In conclusion, critically ill patients receiving the combination of VPT had the highest incidence of AKI compared to critically ill patients receiving either VC or VM.

Changing the Time of Blood Collection to Determine Vancomycin Concentrations in Intensive Care Unit Patients

BACKGROUND

Clinical practice guidelines for initiation and therapeutic drug monitoring, but not timing, of vancomycin dosing exist at many institutions. Scheduling vancomycin trough measurements and doses around the morning blood sample collection could yield more interpretable troughs and increase patient safety.

OBJECTIVE

To evaluate the appropriateness of blood sample collection times for vancomycin trough measurements before and after an initiative to change the timing of blood sampling to determine vancomycin doses and trough levels in a medical intensive care unit.

METHODS

A retrospective cohort study was conducted of patients in a medical intensive care unit who received intravenous vancomycin at a scheduled interval. Differences in continuous and categorical data were compared between pre- and postintervention groups. The primary outcome was proportion of blood samples collected for vancomycin trough measurements within 30 minutes of the next scheduled vancomycin dose.

RESULTS

Baseline characteristics were similar between the preintervention (n = 68) and postintervention (n = 176) groups except for the percentage of blood samples drawn for trough measurements and morning laboratory tests (6% vs 81%; P < .001). Frequency of loading doses was similar between patients in the pre- and postintervention groups, as was weight-based maintenance dosing. There was no significant difference in the percentage of blood samples collected to measure vancomycin trough levels appropriately at 30, 60, or 75 minutes from the next scheduled dose.

CONCLUSION

Measuring vancomycin trough levels in morning blood samples did not affect the percentage of inappropriately collected blood samples used to measure vancomycin trough levels.

Comparative incidence and excess risk of acute kidney injury in hospitalised patients receiving vancomycin and piperacillin/tazobactam in combination or as monotherapy

Combination therapy with vancomycin and piperacillin/tazobactam (TZP) has been associated with increased risk of acute kidney injury (AKI) compared with monotherapy with either agent. This retrospective, matched cohort study was conducted to assess the comparative incidence of AKI due to combination therapy in patients receiving vancomycin and TZP in combination or as monotherapy. Patients aged ≥18 years admitted to Albany Medical Center (Albany, NY) between September 2013 and August 2014 who had received therapy for at least two consecutive days were included. Patients who were pregnant, neutropenic, had AKI on admission or with cystic fibrosis were excluded. Patients were matched on baseline risk of AKI. The main outcome of interest was AKI, defined as an increase in serum creatinine of ≥0.3 mg/L or ≥50% within 48 h. Secondary outcomes evaluated were length of hospital and ICU stay and inpatient mortality associated with AKI. The risk of AKI was 7.0%, 8.5% and 26.8% in the vancomycin monotherapy, TZP monotherapy and combination groups, respectively (P < 0.001). In the multivariate analysis, combination therapy was independently associated with an increased odds of AKI (adjusted odds ratio = 4.406, 95% confidence interval 1.472-13.188) compared with vancomycin monotherapy. The excess risk of combination therapy was 11.3%. In this matched cohort study, there was an increased incidence of AKI in patients receiving vancomycin and TZP combination therapy. Further research is needed to determine the individual strategies to best prevent inpatient AKI in patients receiving this combination therapy.

Vancomycin Plus Piperacillin-Tazobactam and Acute Kidney Injury in Adults: A Systematic Review and Meta-Analysis

OBJECTIVES

The objective of this systematic review and meta-analysis was to assess acute kidney injury with combination therapy of vancomycin plus piperacillin-tazobactam, in general, adult patients and in critically ill adults. Rates of acute kidney injury, time to acute kidney injury, and odds of acute kidney injury were compared with vancomycin monotherapy, vancomycin plus cefepime or carbapenem, or piperacillin-tazobactam monotherapy.

DATA SOURCES

Studies were identified by searching Pubmed, Embase, Web of Science, and Cochrane from inception to April 2017. Abstracts from selected conference proceedings were manually searched.

STUDY SELECTION

Articles not in English, pediatric studies, and case reports were excluded.

DATA EXTRACTION

Two authors independently extracted data on study methods, rates of acute kidney injury, and time to acute kidney injury. Effect estimates and 95% CIs were calculated using the random effects model in RevMan 5.3.

DATA SYNTHESIS

Literature search identified 15 published studies and 17 conference abstracts with at least 24,799 patients. The overall occurrence rate of acute kidney injury was 16.7%, with 22.2% for vancomycin plus piperacillin-tazobactam and 12.9% for comparators. This yielded an overall number needed to harm of 11. Time to acute kidney injury was faster for vancomycin plus piperacillin-tazobactam than vancomycin plus cefepime or carbapenem, but not significantly (mean difference, -1.30; 95% CI, -3.00 to 0.41 d). The odds of acute kidney injury with vancomycin plus piperacillin-tazobactam were increased versus vancomycin monotherapy (odds ratio, 3.40; 95% CI, 2.57-4.50), versus vancomycin plus cefepime or carbapenem (odds ratio, 2.68; 95% CI, 1.83-3.91), and versus piperacillin-tazobactam monotherapy (odds ratio, 2.70; 95% CI, 1.97-3.69). In a small subanalysis of 968 critically ill patients, the odds of acute kidney injury were increased versus vancomycin monotherapy (odds ratio, 9.62; 95% CI, 4.48-20.68), but not significantly different for vancomycin plus cefepime or carbapenem (odds ratio, 1.43; 95% CI, 0.83-2.47) or piperacillin-tazobactam monotherapy (odds ratio, 1.35; 95% CI, 0.86-2.11).

CONCLUSIONS

The combination of vancomycin plus piperacillin-tazobactam increased the odds of acute kidney injury over vancomycin monotherapy, vancomycin plus cefepime or carbapenem, and piperacillin-tazobactam monotherapy. Limited data in critically ill patients suggest the odds of acute kidney injury are increased versus vancomycin monotherapy, and mitigated versus the other comparators. Further research in the critically ill population is needed.

Effects of staff education and standardizing dosing and collection times on vancomycin trough appropriateness in ward patients

BACKGROUND

Many institutions have guidelines for initiation and monitoring, but not timing, of vancomycin.

OBJECTIVE

Our objective was to evaluate vancomycin trough collection appropriateness before and after an initiative to change the dosing and trough collection times in ward patients.

METHODS

A retrospective cohort study of ward patients from May 2014-16 who received scheduled intravenous vancomycin was performed. Nurse managers and pharmacists provided staff education. Differences between pre- and post-intervention groups were compared using student's t-test for continuous data and chi-square test for categorical data.

RESULTS

Baseline characteristics were similar between the pre-intervention (n=124) and post-intervention (n=122) groups except for weight-based maintenance dose (15.3 mg/kg vs. 16.5 mg/kg, p=0.03) and percentage of troughs collected with morning labs (14% vs. 87%, p<0.001). Patients in the pre- and post-intervention groups received a similar frequency of loading doses (14.5% vs. 16%, p=0.68). There was no significant difference in percentage of vancomycin troughs collected appropriately at 30 (40% vs. 42%, p=0.72), 60 (57% vs. 63%, p=0.35), or 75 (60% vs. 68%, p=0.22) minutes from the scheduled time of the next dose.

CONCLUSION

Staff education and standardizing collection of vancomycin troughs with morning blood collections did not affect the percentage of appropriately collected vancomycin troughs.

Acute Kidney Injury in Patients Treated with IV Beta-Lactam/Beta-Lactamase Inhibitor Combinations

STUDY OBJECTIVE

Increased acute kidney injury (AKI) incidence has been reported in patients receiving piperacillin-tazobactam (PTZ) therapy compared with other β-lactams. The authors sought to determine if the addition of β-lactamase inhibitors impacts AKI incidence by comparing patients treated with PTZ or ampicillin-sulbactam (SAM).

DESIGN

Retrospective cohort study.

SETTING

Large academic tertiary care hospital.

PATIENTS

Overall, 2448 patients received PTZ (n=1836) or SAM (n=612) for at least 48 hours between September 1, 2007, and September 30, 2015. Patients were excluded for pregnancy, cystic fibrosis, chronic kidney disease, and initial creatinine clearance < 30 ml/min. Patients were matched on Charlson Comorbidity Index, initial creatinine clearance, hypotension exposure, various nephrotoxic drug exposures, history of diabetes, heart failure, and hypertension.

MEASUREMENTS AND MAIN RESULTS

AKI occurred in 265 patients at similar rates for both groups (PTZ 11.4% vs SAM 9.2%; p=0.14). After stratifying by vancomycin exposure and controlling for confounders, there was no difference in the risk of AKI for SAM or PTZ (adjusted odds ratio [aOR] 0.87, 95% confidence interval [CI] 0.59-1.25). The addition of vancomycin (VAN) to PTZ increased the likelihood of AKI compared with PTZ alone (aOR 1.77, 95% CI 1.26-2.46). Concomitant SAM and VAN therapy was not associated with a significant increase in AKI compared with SAM monotherapy (aOR 1.01, 95% CI 0.48-1.97).

CONCLUSION

Rates of AKI were similar for PTZ and SAM in a matched cohort. The addition of a β-lactamase inhibitor is not likely the mechanism in the observed increased rates of AKI in patients treated with vancomycin and PTZ.

Acute kidney injury in patients treated with vancomycin and piperacillin-tazobactam: A retrospective cohort analysis

BACKGROUND

Empiric antimicrobial therapy often consists of the combination of gram-positive coverage with vancomycin (VAN) and gram-negative coverage, specifically an antipseudomonal beta-lactam such as piperacillin-tazobactam (PTZ). Nephrotoxicity is commonly associated with VAN therapy; however, recent reports show higher nephrotoxicity rates among patients treated with the combination of VAN and PTZ.

OBJECTIVE

This study evaluated the effect of the VAN/PTZ combination on acute kidney injury (AKI) compared to VAN and PTZ monotherapies.

DESIGN, SETTING, AND PATIENTS

This is a retrospective cohort analysis of adult patients without renal disease receiving VAN, PTZ, or the combination from September 1, 2010 through August 31, 2014 at an academic medical center.

MEASUREMENTS

The primary outcome was AKI incidence as defined by the Risk, Injury, Failure, Loss, End-stage (RIFLE) criteria.

METHODS

Continuous and categorical variables were assessed with appropriate tests. Univariate and multivariate logistic regressions were performed to assess for associations between variables and AKI incidence. Subanalyses based on severity of illness were performed.

RESULTS

Overall, 11,650 patients were analyzed, with 1647 (14.1%) developing AKI. AKI was significantly more frequent in the VAN/PTZ group (21%) compared to either monotherapy group (VAN 8.3%, PTZ 7.8%, P ⟨ 0.001 for both). Combination therapy was independently associated with higher AKI odds compared to monotherapy with either agent (adjusted odds ratio [aOR], 2.03; 95% confidence interval [CI], 1.74-2.39; aOR, 2.31; 95% CI, 1.97-2.71, for VAN and PTZ, respectively). Receipt of concomitant nephrotoxic drugs was independently associated with increased AKI rates, as were increased duration of therapy, hospital length of stay, increasing severity of illness, and increasing baseline renal function.

CONCLUSIONS

In this study of more than 10,000 patients, VAN combined with PTZ was associated with twice the odds of AKI development compared to either agent as monotherapy. This demonstrates the need for judicious use of combination empiric therapy. Journal of Hospital Medicine 2017;12:77-82.

Nephrotoxicity during Vancomycin Therapy in Combination with Piperacillin-Tazobactam or Cefepime

Recent reports have demonstrated that vancomycin (VAN) may lead to an increase in the incidence of acute kidney injury (AKI) when it is combined with antipseudomonal beta-lactams. This study compared the incidence of AKI associated with VAN plus piperacillin-tazobactam (TZP) or cefepime (FEP). This was a retrospective, matched cohort study that was conducted at an academic medical center between September 2010 and September 2014 and that included adult patients without severe chronic or structural kidney disease, dialysis, pregnancy, cystic fibrosis, or a hospital transfer receiving TZP-VAN or FEP-VAN for at least 48 h. The primary outcome was the difference in the AKI incidence between the TZP-VAN and FEP-VAN groups, evaluated using the risk, injury, failure, loss of kidney function, and end-stage kidney disease (RIFLE) criteria. Patients in the two groups were matched on the basis of age, sex, severity of illness, baseline creatinine clearance, hypotension, number of nephrotoxicity risk factors, and intravenous contrast exposure. In total, 4,193 patients met all inclusion criteria (3,605 received TZP-VAN and 588 received FEP-VAN). The unadjusted AKI incidence was 21.4% in patients receiving TZP-VAN, whereas it was 12.6% in patients receiving FEP-VAN (P < 0.001). After the patients were matched, 1,633 patients receiving TZP-VAN and 578 patients receiving FEP-VAN were evaluated. The AKI incidence remained higher in patients receiving TZP-VAN than in those receiving FEP-VAN (21.4% versus 12.5%, P < 0.0001). This trend remained true for all classifications of the RIFLE criteria. After controlling for remaining confounders, TZP-VAN therapy was associated with 2.18 times the odds of AKI than FEP-VAN therapy (95% confidence interval, 1.64 to 2.94 times) in logistic regression. AKI was significantly more common in patients receiving vancomycin in combination with piperacillin-tazobactam than in those receiving vancomycin in combination with cefepime. This finding reinforces the need for the judicious use of combination empirical antimicrobial therapy.