Implementing AUC Monitoring in a Pharmacist-Managed Vancomycin Dosing Protocol: A Retrospective Cohort Study

Background

Consensus guidelines on the therapeutic drug monitoring of vancomycin published in 2020 recognize that using the calculated area-under-the-curve (AUC) to guide dosing maximizes clinical efficacy and minimizes risk when compared to traditional trough-based dosing. The purpose of this study was to determine whether AUC monitoring results in reduced acute kidney injury (AKI) rates in adult patients receiving vancomycin for all indications.

Methods

In this study, patients 18 years or older who received pharmacist-managed vancomycin therapy were selected using pharmacy surveillance software from 2 timeframes. Patients were excluded if they received less than 48 hours of therapy or had unstable renal function or hemodialysis at baseline. The primary outcome measured was the incidence of AKI in each group of patients.

Results

Data were collected for 121 patients in each group. Concomitant nephrotoxins used in each group, as well as the sources of infection, were similar between groups. AUC monitoring did not result in a significant decrease in AKI rate (16.5% in AUC group, 14.9% in trough group; P = .61). However, patients who received AUC monitoring were more likely to be therapeutic at first follow-up compared to the trough monitoring group (43.2% in AUC group, 33.9% in trough group; P = .03). AUC monitoring also resulted in lower trough levels and total daily doses, with no difference in mortality or length of stay.

Conclusion

AUC monitoring did not result in an observed decrease in AKI rate. Despite this, the AUC monitoring protocol was effective at reaching the goal AUC of 400-600 mg*hour/L and did not increase mortality or length of stay.

Clinical Impact of Oral Step-Down Therapy for Gram-Negative Bacteremia: A Retrospective Study

Background

In recent years, there has been a growing body of evidence that supports oral step-down therapy for the treatment of gram-negative bacteremia. The purpose of this study was to compare outcomes for hospitalized patients who received intravenous-only (IV-only) therapy versus oral step-down therapy with low, moderate, and highly bioavailable antimicrobials for the treatment of gram-negative bacteremia.

Methods

In this retrospective, single-center, observational study, we examined data from adult patients hospitalized with gram-negative bacteremia in a 1-year period. Data analysis was performed using information collected from electronic medical records and a clinical surveillance system.

Results

A total of 199 patients were included in this study. Patients in the IV-only group had higher Charlson comorbidity index scores at baseline and higher rates of intensive care unit admission while bacteremic (P = .0096 and .0026, respectively). The primary outcome of 30-day all-cause mortality was significantly lower in the oral step-down group (P < .0001). Secondary outcomes of 30-day bacteremia recurrence, line-associated complications, and hospital length of stay were similar between groups. The total duration of antibiotic therapy was one day longer for oral step-down patients (P = .0015) and the estimated cost of antibiotic therapy was significantly lower in this group (P < .00001).

Conclusion

In this retrospective study, oral step-down therapy was not associated with increased 30- day all-cause mortality. Oral step-down therapy was also more cost-effective than IV-only therapy, while both groups had similar bacteremia recurrence within 30 days.

Inhaled antibiotics for pulmonary exacerbations in cystic fibrosis

BACKGROUND

Cystic fibrosis is a genetic disorder in which abnormal mucus in the lungs is associated with susceptibility to persistent infection. Pulmonary exacerbations are when symptoms of infection become more severe. Antibiotics are an essential part of treatment for exacerbations and inhaled antibiotics may be used alone or in conjunction with oral antibiotics for milder exacerbations or with intravenous antibiotics for more severe infections. Inhaled antibiotics do not cause the same adverse effects as intravenous antibiotics and may prove an alternative in people with poor access to their veins. This is an update of a previously published review.

OBJECTIVES

To determine if treatment of pulmonary exacerbations with inhaled antibiotics in people with cystic fibrosis improves their quality of life, reduces time off school or work, and improves their long-term lung function.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis Group's Cystic Fibrosis Trials Register. Date of the last search: 7 March 2022. We also searched ClinicalTrials.gov, the Australia and New Zealand Clinical Trials Registry and WHO ICTRP for relevant trials. Date of last search: 3 May 2022.

SELECTION CRITERIA

Randomised controlled trials in people with cystic fibrosis with a pulmonary exacerbation in whom treatment with inhaled antibiotics was compared to placebo, standard treatment or another inhaled antibiotic for between one and four weeks.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected eligible trials, assessed the risk of bias in each trial and extracted data. They assessed the certainty of the evidence using the GRADE criteria. Authors of the included trials were contacted for more information.

MAIN RESULTS

Five trials with 183 participants are included in the review. Two trials (77 participants) compared inhaled antibiotics alone to intravenous antibiotics alone and three trials (106 participants) compared a combination of inhaled and intravenous antibiotics to intravenous antibiotics alone. Trials were heterogenous in design and two were only available in abstract form. Risk of bias was difficult to assess in most trials but, for four out of five trials, we judged there to be a high risk from lack of blinding and an unclear risk with regards to randomisation. Results were not fully reported and only limited data were available for analysis. One trial was a cross-over design and we only included data from the first intervention arm. Inhaled antibiotics alone versus intravenous antibiotics alone Only one trial (18 participants) reported a perceived improvement in lifestyle (quality of life) in both groups (very low-certainty evidence). Neither trial reported on time off work or school. Both trials measured lung function, but there was no difference reported between treatment groups (very low-certainty evidence). With regards to our secondary outcomes, one trial (18 participants) reported no difference in the need for additional antibiotics and the second trial (59 participants) reported on the time to next exacerbation. In neither case was a difference between treatments identified (both very low-certainty evidence). The single trial (18 participants) measuring adverse events and sputum microbiology did not observe any in either treatment group for either outcome (very low-certainty  evidence). Inhaled antibiotics plus intravenous antibiotics versus intravenous antibiotics alone Inhaled antibiotics plus intravenous antibiotics may make little or no difference to quality of life compared to intravenous antibiotics alone. None of the trials reported time off work or school. All three trials measured lung function, but found no difference between groups in forced expiratory volume in one second (two trials; 44 participants; very low-certainty evidence) or vital capacity (one trial; 62 participants). None of the trials reported on the need for additional antibiotics. Inhaled plus intravenous antibiotics may make little difference to the time to next exacerbation; however, one trial (28 participants) reported on hospital admissions and found no difference between groups. There is likely no difference between groups in adverse events (very low-certainty evidence) and one trial (62 participants) reported no difference in the emergence of antibiotic-resistant organisms (very low-certainty evidence).

AUTHORS' CONCLUSIONS

We identified only low- or very low-certainty evidence to judge the effectiveness of inhaled antibiotics for the treatment of pulmonary exacerbations in people with cystic fibrosis. The included trials were not sufficiently powered to achieve their goals. Hence, we are unable to demonstrate whether one treatment was superior to the other or not. Further research is needed to establish whether inhaled tobramycin may be used as an alternative to intravenous tobramycin for some pulmonary exacerbations.