Compliance with recommended pneumococcal vaccination schedule in patients treated for rheumatoid arthritis: A retrospective cohort study in the Veterans Affairs population

INTRODUCTION

Invasive pneumococcal disease (IPD) is a leading cause of death. Rheumatoid arthritis (RA) patients are at risk of IPD due to immunosuppressant medications. Up until 2022, two pneumococcal vaccines, the 13-valent Pneumococcal conjugate vaccine (PCV13) and pneumococcal polysaccharide vaccine (PPSV23), were recommended. Despite the recommendation change to give a single 20-valent PCV vaccine (PCV20), some still require multiple vaccinations. There is a need to identify barriers to vaccine uptake.

METHODS

We conducted a retrospective cohort study to assess the on-time vaccination rates for PCV13 and PPSV23 in treated RA patients between 2010 and 2018 using national Veterans Affairs data. Patients > 18 years of age diagnosed with RA and newly initiated on RA treatment were included. Pneumococcal vaccine compliance was assessed by measuring on-time receipt of PCV13 and PPSV23 vaccinations. We identified factors using multivariate logistic regression and described the occurrence of these factors using descriptive statistics.

RESULTS

A total of 39,243 patients were included in the study. Most patients were white (75.8 %), male (85.4 %), on methotrexate therapy (41.4 %). The average age was 62.3 years. The proportion of patients considered vaccine compliant is 43.9 %. The primary independent risk factors for vaccine non-compliance were black/African American race (Odds Ratio [OR] 1.26, 95 % Confidence Interval [CI] 1.19-1.34) or missing/unknown race (OR 1.45, 95 % CI 1.31-1.61), missing/unknown ethnicity (OR 1.21, 1.02-1.43), never married (OR 1.10, 95 % CI 1.02-1.19) or widowed (OR 1.23, 95 % CI 1.12-1.34), diagnosed with congestive heart failure (OR 1.10, 95 % CI 1.00-1.22), or dementia (OR 1.48, 95 % CI 1.16-1.91). The proportion of patients who were non-compliant in patients who were vaccine naïve was 32.1 % and the non-compliance rate for non-naïve patients was 65.3 %.

CONCLUSIONS

Providers should identify barriers to pneumococcal vaccination in RA patients to improve compliance. Efforts to increase vaccination should be tailored to specific high-risk groups.

Insufficient Representation of Patients With Obesity in Randomized Controlled Trials Evaluating the Efficacy and Safety of Antimicrobials for Treatment of Skin and Skin Structure Infections: A Scoping Review

Persons with obesity (PwO) represent approximately 50% of acute bacterial skin and skin structure infections (ABSSSIs) in the United States (US). There are currently insufficient data in PwO for drugs used for ABSSSIs. We conducted a scoping review of randomized controlled trials (RCTs) published between 2000 and 2022 to describe how frequently body size measures were reported. Weight and/or body mass index (BMI) were recorded in approximately 50% of the 69 RCTs. The average weights or BMIs were lower than US averages for most RCTs reporting data. None evaluated the impact of body size on outcomes in the original publication. Only 30% of newly approved drugs mention PwO representation in the prescribing information. More representative recruitment of PwO into RCTs is needed to help clinicians evaluate efficacy in these patients. We suggest that the Food and Drug Administration require companies to submit plans to ensure adequate PwO inclusion and that authors of RCTs report subgroup results based on body size.

Evaluation of Scholarship Motivators and Barriers for Non-Tenure-Track Faculty in a Department of Pharmacy Practice

The Accreditation Council for Pharmacy Education (ACPE) Standards 2016 set explicit expectations for faculty scholarship. However, many non-tenure-track faculty have struggled with the scholarship portion of the academic tripart mission of clinical practice, teaching, and scholarship. Therefore, we sought to identify themes regarding the barriers, motivators, and potential solutions associated with non-tenure-track faculty scholarship. Four focus group interviews were held via videoconference during July 2021, which consisted of non-tenure-track faculty within the TTUHSC Jerry H. Hodge School of Pharmacy. Each focus group answered a standard script of questions that were evaluated for face validity over a 30-60 min session. Twenty-two non-tenure-track faculty members (47% response) participated in one of the four focus group interviews. The four common barriers were insufficient time, lack of acknowledgment, obscurity of scholarship expectations, and a lack of resources and support. Scholarship's lasting impact on academia, students, and clinical practice was the one common motivator identified by the groups. The barriers identified were not unique to our faculty, despite the unique four-city structure of our program. Actions have continued to be taken to help address the barriers and potential solutions identified by the focus groups. In summary, our results echo that non-tenure-track faculty need more time and training to help them feel like they can meet institutional scholarship requirements.

Controversies in the Prevention and Treatment of Clostridioides difficile Infection in Adults: A Narrative Review

Clostridioides difficile remains a problematic pathogen resulting in significant morbidity and mortality, especially for high-risk groups that include immunocompromised patients. Both the Infectious Diseases Society of America and the Society for Healthcare Epidemiology of America (IDSA/SHEA), as well as the American College of Gastroenterology (ACG) and the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) recently provided guideline updates for C. difficile infection (CDI). In this narrative review, the authors reviewed available literature regarding the prevention or treatment of CDI in adults and focused on disagreements between the IDSA/SHEA and ACG guidelines, as well as articles that have been published since the updates. Several options for primary prophylaxis are available, including probiotics and antibiotics (vancomycin, fidaxomicin). The literature supporting fidaxomicin is currently quite limited. While there are more studies evaluating probiotics and vancomycin, the optimal patient populations and regimens for their use have yet to be defined. While the IDSA/SHEA guidelines discourage metronidazole use for mild CDI episodes, evidence exists that it may remain a reasonable option for these patients. Fidaxomicin has an advantage over vancomycin in reducing recurrences, but its use is limited by cost. Despite this, recent studies suggest fidaxomicin's cost-effectiveness as a first-line therapy, though this is highly dependent on institutional contracts and payment structures. Secondary prophylaxis should focus on non-antimicrobial options to lessen the impact on the microbiome. The oral option of fecal microbiota transplantation (FMT), SER109, and the now FDA-approved RBX2660 represent exciting new options to correct dysbiosis. Bezlotoxumab is another attractive option to prevent recurrences. Further head-to-head studies of newer agents will be needed to guide selection of the optimal therapies for CDI primary and secondary prophylaxis.

The Risk and Clinical Implications of Antibiotic-Associated Acute Kidney Injury: A Review of the Clinical Data for Agents with Signals from the Food and Drug Administration’s Adverse Event Reporting System (FAERS) Database

Antibiotic-associated acute kidney injury (AA-AKI) is quite common, especially among hospitalized patients; however, little is known about risk factors or mechanisms of why AA-AKI occurs. In this review, the authors have reviewed all available literature prior to 1 June 2022, with a large number of AKI reports. Information regarding risk factors of AA-AKI, mechanisms behind AA-AKI, and treatment/management principles to decrease AA-AKI risk were collected and reviewed. Patients treated in the inpatient setting are at increased risk of AA-AKI due to common risk factors: hypovolemia, concomitant use of other nephrotoxic medications, and exacerbation of comorbid conditions. Clinicians should attempt to correct risk factors for AA-AKI, choose antibiotic therapies with decreased association of AA-AKI to protect their high-risk patients, and narrow, when clinically possible, the use of antibiotics which have decreased incidence of AKI. To treat AKI, it is still recommended to discontinue all offending nephrotoxic agents and to renally adjust all medications according to package insert recommendations to decrease patient harm.

Using the HyFlex model to deliver a capstone seminar course

INTRODUCTION

The HyFlex course structure allows students to attend class in-person or via synchronous videoconferencing technology. This model has been described, but no data are available in pharmacy curricula.

METHODS

Students enrolled in Grand Rounds (GR) were eligible. The GR Engagement Assessment Tool (GREAT) measured engagement three times during the semester. Eighteen statements across four domains were rated using a five-point Likert scale (1 = not true at all and 5 = completely true). Free-text responses were collected for qualitative analysis. The primary outcome was the difference in GR engagement between students attending in-person vs. remotely. Descriptive statistics were used for demographic information. Wilcoxon rank-sum tests compared Likert-scale responses between in-person and remote attendance.

RESULTS

Surveys included 128 responses from 88 unique students. There were no differences between remote and in-person attendance for the boredom and elaboration domains. In-person students reported listening more intently (median 4, IQR [3,4]; P = .03). In-person students felt the material was more practical (median 4, IQR [4,5]) than remote students (median 4, IQR [3,4]; P = .002) and more applicable to other situations (median 3, IQR [3,5]) than remote students (median 3, IQR [2,4]; P = .04). Qualitative analysis of the entire cohort demonstrated five themes for satisfaction: safety, flexibility, convenience, technology, and professionalism.

CONCLUSIONS

There were subtle differences in student engagement or satisfaction using the HyFlex model. This study supports the expansion of this methodology to similar courses where remote instruction is needed.

The Risk of Clostridioides difficile Recurrence after Initial Treatment with Vancomycin or Fidaxomicin Utilizing Cerner Health Facts

(1) Background: Fidaxomicin has been shown to significantly reduce Clostridioides difficile infection (CDI) recurrences rates in randomized, controlled trials. However, national data from the Veterans Affairs has called the real-world applicability of these findings into question. Therefore, we conducted a retrospective cohort study of patients receiving fidaxomicin or vancomycin as initial therapy for an index case of CDI in the hospital to evaluate the relative rates CDI recurrence within 90 days of an index case. (2) Methods: We retrieved patients 18 years and older who were admitted between July 2011 through June 2018 and diagnosed and treated for CDI with vancomycin or fidaxomicin. The first occurrence of CDI with treatment was designated as the index case. Patients with CDI within 1 year prior to index case were excluded. From the remaining index cases (vancomycin = 14,785; fidaxomicin = 889) the primary outcome (a recurrence of CDI within 90 days of the index case) was determined. The CDI recurrence rates for fidaxomicin and vancomyicn were evaluated using a Cox Proportional Hazards model on a propensity score matched cohort. (3) Results: A statistically significantly lower risk of CDI recurrence was observed with fidaxomicin use in the matched cohort (889 patients per treatment) using a Cox Proportional Hazards model (HR 0.67, 95% CI 0.50–0.90). (4) Conclusions: Fidaxomicin was independently associated with a decreased CDI recurrence, as defined by readmission for CDI within 90 days.

Low Prevalence of Thrombosis Prophylaxis Dose Adjustments Highlights Implications for Patient Safety

Background: Pharmacologic thromboprophylaxis (PTP) is the mainstay prevention strategy for venous thromboembolism (VTE). PTP agents traditionally dosed, like unfractionated heparin (UFH) and enoxaparin (ENOX), are associated with failure and bleeding in obese and underweight patients, respectively.

Objectives: This study aimed to describe the prevalence of unadjusted ENOX and UFH dosing for PTP based on anthropometric measures.

Patients/Methods:This was a post-hoc, multicenter, cross–sectional analysis of critically ill adults receiving PTP with ENOX or UFH. The primary outcome was the prevalence of unadjusted PTP based on body mass index (BMI) and total body weight (TBW). Definitions for dose adjustments were developed based on existing literature. A secondary outcome was to identify factors associated with unadjusted dosing per BMI and TBW using multivariable generalized linear mixed-effect models.

Results: The nested cohort included 172 patients (ENOX=46, UFH=126). Unadjusted PTP was observed in 118 patients (68.6%) based on BMI and 74 (43%) per TBW. When comparing UFH to ENOX, more patients who received UFH had doses unadjusted by BMI (78.6% vs. 41.3%, p<0.05) but not TBW (43.7% vs. 41.3%). Factors independently associated with unadjusted PTP per BMI were receipt of UFH (OR 6.93, 95% CI 1.06-8.77) or a BMI underweight or overweight/obese (OR 10.45, 95% CI 4.38-24.92). Having a TBW <50kg or >100kg (OR 4.85, 95% CI 2.15-10.96) were independently associated with unadjusted PTP based on TBW.

Conclusions: Unadjusted dosing of PTP occurs frequently in critically ill adults receiving ENOX or UFH. This was seen in body size extremes by both BMI and TBW.

Efficacy and benefits of mock residency interviews

INTRODUCTION

Obtaining a residency has become more competitive as more pharmacy students seek postgraduate training. This is likely due to pharmacist positions increasing in clinical settings. To be fully prepared, students seeking residency positions should be trained for the interview process by their pharmacy school.

METHODS

Mock residency interviews (MRI) were conducted at the Texas Tech University Health Sciences Center School of Pharmacy which included components of typical residency interviews. The primary outcome compared residency match rates for MRI participants vs. non-participants. Secondary outcomes evaluated student preparedness, student and faculty feedback, and satisfaction/benefit of the event along with comparison of school vs. national match rate and assessment of those matching compared to grade point average (GPA).

RESULTS

Match rates were similar between MRI participants vs. non-participants (75% vs. 73%) with significant difference in Phase I match rates between MRI participants vs. non-participants (75% vs. 51%, P = .007). MRI was significantly associated with Phase I matching in the multivariable analysis (odds ratio (OR) = 2.81, 95% CI 1.27-6.22). The overall school's match rate exceeded the national two out of three years in the quality improvement project period. GPA was the only other factor independently associated with Phase I matching (OR = 1.15, 95% CI 1.01-1.32). Students and faculty consistently reported positive feedback following participation.

CONCLUSIONS

MRI are valuable and are making a difference as indicated by improved Phase I match rates for those that participated. Students and faculty reported an increase in preparedness and overall satisfaction after attending MRI.

Pharmacists Without Access to the EHR: Practicing with One Hand Tied Behind Our Backs

Pharmacists are the most accessible healthcare professionals to the public, yet have the least amount of information from the electronic health record available to them. This lack of information makes ensuring that patients are receiving proper medications and monitoring for efficacy and safety a challenge, if not impossible in some situations. Having access to a national electronic health record would provide pharmacists with this needed information to truly engage with prescribers as fellow clinical experts in the field. Sharing prescription information for non-controlled substances would also decrease the likelihood of a patient receiving duplicative therapy from two prescribers or pharmacies that may not know what the other is doing. There are already examples of successful national data sharing including the Prescription drug Monitoring Program for controlled substances as well as the Veterans Affairs healthcare system. Therefore, our profession needs to push for nationwide access to patient electronic health records, which includes all healthcare providers. This will facilitate the inclusion of pharmacists in the optimization of the care of patients who need our expertise in managing their medication regimens as well as build better relationships with prescribing providers.

Effects of Propofol on Hemodynamic Profile in Adults Receiving Targeted Temperature Management

Background: Propofol is a key component for the management of sedation and shivering during targeted temperature management (TTM) following cardiac arrest. The cardiac depressant effects of propofol have not been described during TTM and may be especially relevant given the stress to the myocardium following cardiac arrest. The purpose of this study is to describe hemodynamic changes associated with propofol administration during TTM. Methods: This single center, retrospective cohort study evaluated adult patients who received a propofol infusion for at least 30 minutes during TTM. The primary outcome was the change in cardiovascular Sequential Organ Failure Assessment (cvSOFA) score 30 minutes after propofol initiation. Secondary outcomes included change in systolic blood pressure (SBP), mean arterial pressure (MAP), heart rate (HR), and vasopressor requirements (VR) expressed as norepinephrine equivalents at 30, 60, 120, 180, and 240 minutes after propofol initiation. A multivariate regression was performed to assess the influence of propofol and body temperature on MAP, while controlling for vasopressor dose and cardiac arrest hospital prognosis (CAHP) score. Results: The cohort included 40 patients with a median CAHP score of 197. The goal temperature of 33°C was achieved for all patients. The median cvSOFA score was 1 at baseline and 0.5 at 30 minutes, with a non-significant change after propofol initiation ( P = .96). SBP and MAP reductions were the greatest at 60 minutes (17 and 8 mmHg; P < .05 for both). The median change in HR at 120 minutes was −9 beats/minute from baseline. This reduction was sustained through 240 minutes ( P < .05). No change in VR were seen at any time point. In multivariate regression, body temperature was the only characteristic independently associated with changes in MAP (coefficient 4.95, 95% CI 1.6-8.3). Conclusion: Administration of propofol during TTM did not affect cvSOFA score. The reductions in SBP, MAP, and HR did not have a corresponding change in vasopressor requirements and are likely not clinically meaningful. Propofol appears to be a safe choice for sedation in patients receiving targeted temperature management after cardiac arrest.

Preoperative imaging of glioblastoma patients using hyperpolarized 13C pyruvate: Potential role in clinical decision making

Background

Glioblastoma remains incurable despite treatment with surgery, radiation therapy, and cytotoxic chemotherapy, prompting the search for a metabolic pathway unique to glioblastoma cells.¹³C MR spectroscopic imaging with hyperpolarized pyruvate can demonstrate alterations in pyruvate metabolism in these tumors.

Methods

Three patients with diagnostic MRI suggestive of a glioblastoma were scanned at 3 T 1–2 days prior to tumor resection using a ¹³C/¹H dual-frequency RF coil and a ¹³C/¹H-integrated MR protocol, which consists of a series of ¹H MR sequences (T₂ FLAIR, arterial spin labeling and contrast-enhanced [CE] T₁) and ¹³C spectroscopic imaging with hyperpolarized [1-¹³C]pyruvate. Dynamic spiral chemical shift imaging was used for ¹³C data acquisition. Surgical navigation was used to correlate the locations of tissue samples submitted for histology with the changes seen on the diagnostic MR scans and the ¹³C spectroscopic images.

Results

Each tumor was histologically confirmed to be a WHO grade IV glioblastoma with isocitrate dehydrogenase wild type. Total hyperpolarized ¹³C signals detected near the tumor mass reflected altered tissue perfusion near the tumor. For each tumor, a hyperintense [1-¹³C]lactate signal was detected both within CE and T₂-FLAIR regions on the ¹H diagnostic images (P = .008). [¹³C]bicarbonate signal was maintained or decreased in the lesion but the observation was not significant (P = .3).

Conclusions

Prior to surgical resection, ¹³C MR spectroscopic imaging with hyperpolarized pyruvate reveals increased lactate production in regions of histologically confirmed glioblastoma.

Do the types and routes of proton pump inhibitor treatments affect clostridium difficile in ICU patients? A retrospective cohort study

Background: : Proton pump inhibitors (PPI) are associated with Clostridium difficile infection (CDI). Impact of the route of administration is unknown.Research Design and Methods: Patients in Multiparameter Intelligent Monitoring in Intensive Care II database (MIMIC-II) from 2001 to 2008, >18 years old, admitted to medical, surgical, or cardiac ICUs were included. PPI exposures were omeprazole, esomeprazole, lansoprazole, and pantoprazole. PPI administration routes were oral or intravenous. Patients who received histamine receptor antagonists (H2RA) were the control arm. CDI was identified using ICD-9 diagnostic code 008.45. Multiple logistic regression analysis was performed to calculate odds ratios (OR).Results: The study included 16,820 patients (57% male) with a mean age of 63 (SD±17) years and hospitalization duration of 10.2 days (SD±11). Pantoprazole was the most common PPI (94%). CDI occurred in 2.4% and more in patients receiving PPIs than H2RAs (3.0% vs. 0.8%, p < 0.001). CDI prevalence increased with intravenous (95%CI = 1.69-3.39, OR 2.4) and oral (95%CI = 1.59-3.27, OR 2.3) PPI use compared to H2RAs. CDI prevalence was not associated with PPI route in the multivariable model (OR 1.07, 95%CI 0.86-1.34).Conclusions: Both intravenous and oral PPI use in the ICU were independently associated with CDI.

Characterization and compensation of f 0 inhomogeneity artifact in spiral hyperpolarized 13 C imaging of the human heart

PURPOSE

This study aimed to investigate the role of regional f 0 inhomogeneity in spiral hyperpolarized ¹³ C image quality and to develop measures to alleviate these effects.

METHODS

Field map correction of hyperpolarized ¹³ C cardiac imaging using spiral readouts was evaluated in healthy subjects. Spiral readouts with differing duration (26 and 45 ms) but similar resolution were compared with respect to off-resonance performance and image quality. An f 0 map-based image correction based on the multifrequency interpolation (MFI) method was implemented and compared to correction using a global frequency shift alone. Estimation of an unknown frequency shift was performed by maximizing a sharpness objective based on the Sobel variance. The apparent full width half at maximum (FWHM) of the myocardial wall on [¹³ C]bicarbonate was used to estimate blur.

RESULTS

Mean myocardial wall FWHM measurements were unchanged with the short readout pre-correction (14.1 ± 2.9 mm) and post-MFI correction (14.1 ± 3.4 mm), but significantly decreased in the long waveform (20.6 ± 6.6 mm uncorrected, 17.7 ± 7.0 corrected, P = .007). Bicarbonate signal-to-noise ratio (SNR) of the images acquired with the long waveform were increased by 1.4 ± 0.3 compared to those acquired with the short waveform (predicted 1.32). Improvement of image quality was observed for all metabolites with f 0 correction.

CONCLUSIONS

f 0 -map correction reduced blur and recovered signal from dropouts, particularly along the posterior myocardial wall. The low image SNR of [¹³ C]bicarbonate can be compensated with longer duration readouts but at the expense of increased f 0 artifacts, which can be partially corrected for with the proposed methods.

1319. Pharmacokinetics of Ceftolozane/Tazobactam in Patients with Burns

Background

Antimicrobial dosing in moderate/severe burns patients is complicated due to the potential unpredictable hyperdynamic pathophysiologic states including 1) hypoproteinemia, 2) acute kidney injury and 3) onset of septicemia. Therefore, distribution assumptions about the population pharmacokinetic (PopPK) profiles of either endogenous or xenobiotic pharmacophores in this patient population can lead to biased parameter estimates. In order to prevent potential bias an agnostic nonparametric adaptive grid approach to describe ceftolozane/tazobactam (C/T) PopPK profiles in patients with partial- and full-thickness burns was employed.

Methods

A human clinical PK study in burn patients was conducted using the standard approved dose of C/T (2 grams/1 gram). A single intravenous dose was administered over 60 minutes. Whole blood was obtained pre-dose and at 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, 8, 12, 16, and 24 hours following the start of infusion. LC-MS/MS bioanalytical methods were developed, validated and employed to determine C/T concentrations in human plasma. PopPK were modeled using Pmetrics package for R. One-, two- and three-compartment models were examined and compared. The influence of several parameters, including %body surface area burns, creatinine clearance (CrCL), weight, albumin and age were tested.

Results

The bioanalytical method for determination of C/T in human plasma met all recommended criteria of the LC-MS/MS. Five males and one female (ages 24 to 66 years), contributed 148 plasma PK samples. The female had 35% partial-thickness burns. The males had full-thickness burns ranging from 27 to 66%. The median CrCL was 104 mL/min (range 73-148 mL/min). Two-compartment model with absorption (Ka) from compartment 1 to 2 and elimination from compartment 2 (Ke), with nonlinear interactions between C/T elimination and CrCL best described the data. Figure A show that bias was minimal. Importantly, both drugs exhibited marked variability for both volume and elimination (Table), since volume was bimodally distributed (Figure B).

A) Observation-versus-Prediction; B) Estimated Ke, V and Ka population parameter densities

Conclusion

C/T exhibited high variability surpassing that observed with severe infections, suggesting that dose adjustment and/or may be therapeutic drug monitoring may be needed to balance target attainment from dose-related toxicities.

Disclosures

Ronald G. Hall, II, PharmD, MSCS, Medical Titan Group (Grant/Research Support)Merck (Research Grant or Support)

Development and validation of a quantitative LC-MS/MS method for the simultaneous determination of ceftolozane and tazobactam in human plasma and urine

The purpose of this work was to develop and validate a single sensitive, selective and rapid bioanalytical method to determine ceftolozane and tazobactam concentrations in human plasma and urine and to use this method to analyze samples from a human clinical study. Human plasma and urine samples were prepared by protein precipitation using a solution of acetonitrile, water and formic acid. Following protein precipitation, samples were analyzed by liquid chromatography tandem mass spectrometry. Chromatographic resolution was achieved on a Kinetex PFP column using a gradient elution, a flow rate of 0.4 mL/min, and a total run time of 5 min. Positive electrospray ionization was employed and analytes were quantitated using multi-reaction monitoring mode. Method validation was conducted in accordance with Unites States Food and Drug Administration's regulatory guidelines for bioanalytical method validation. Calibration curves were determined to linear over the range of 0.1 to 40 µg/mL for ceftolozane and 0.05 to 20 µg/mL for tazobactam. The method was determined to be accurate (-6.24 to 12.53 percent relative error), precise (less than 13.28 percent standard deviation) and sensitive in both human plasma and urine. Ceftolozane and tazobactam were determined to be stable across a battery of stability studies including autosampler, benchtop, freeze/thaw and long-term stability. This validated method successfully applied to human clinical samples to determine the concentration versus time profiles of the intravenously administered combination of Zerbaxa (ceftolozane-tazobactam) in burn patients.

Imaging Acute Metabolic Changes in Patients with Mild Traumatic Brain Injury Using Hyperpolarized [1-13C]Pyruvate

Traumatic brain injury (TBI) involves complex secondary injury processes following the primary injury. The secondary injury is often associated with rapid metabolic shifts and impaired brain function immediately after the initial tissue damage. Magnetic resonance spectroscopic imaging (MRSI) coupled with hyperpolarization of ¹³C-labeled substrates provides a unique opportunity to map the metabolic changes in the brain after traumatic injury in real-time without invasive procedures. In this report, we investigated two patients with acute mild TBI (Glasgow coma scale 15) but no anatomical brain injury or hemorrhage. Patients were imaged with hyperpolarized [1-¹³C]pyruvate MRSI 1 or 6 days after head trauma. Both patients showed significantly reduced bicarbonate (HCO₃^–) production, and one showed hyperintense lactate production at the injured sites. This study reports the feasibility of imaging altered metabolism using hyperpolarized pyruvate in patients with TBI, demonstrating the translatability and sensitivity of the technology to cerebral metabolic changes after mild TBI.

•

Clinical translation of hyperpolarized pyruvate to TBI was demonstrated

•

Patients with mild TBI were imaged with hyperpolarized [1-¹³C]pyruvate

•

Altered lactate and HCO₃^– production in the brain nearest the site of trauma

Impact of Neostigmine and Sugammadex on Time to Leaving the Operating Room in a Community Hospital

Purpose

The purpose of this study was to evaluate the impact of sugammadex on operating room (OR) times versus neostigmine in patients recovering from rocuronium or vecuronium induced neuromuscular blockade.

Methods

This retrospective cohort study evaluated patients 18 years or older with an American Society of Anesthesiologists (ASA) physical status of I-III who received sugammadex or neostigmine (January- October 2017) for reversal of rocuronium or vecuronium at a 500 bed, community hospital. Patients who were pregnant or breastfeeding were excluded. The primary outcome measure was the time from sugammadex or neostigmine administration to OR exit. The primary outcome was evaluated using a linear regression model adjusting for inpatient procedures, age, sex, body mass index, and ASA score. Secondary outcomes included the incidence of bradycardia as well as nausea and vomiting.

Results

The baseline characteristics of the patients in the cohort (sugammadex=134, neostigmine=143) were similar. The median time from drug administration to OR exit was similar for neostigmine and sugammadex (16 vs. 15.5 minutes, p=0.11). Sugammadex had a statistically significant reduction in time from drug administration to OR exit (coefficient -2.7 minutes, 95% confidence interval -5.2 to -0.2 minutes) in the multivariable linear regression model. Sugammadex had lower rates of bradycardia (5.6 vs. 2.2%) or nausea and vomiting (18 vs. 11%) that did not reach statistical significance.

Conclusions

Sugammadex had statistically shorter OR exit times after drug administration in the cohort. The mean 2.7 minute benefit is unlikely to be clinically meaningful and limits its application in practice unless larger cohorts detect a benefit due to a significant reduction.in.adverse.events.

Impact of total body weight on rate of acute kidney injury in patients treated with piperacillin-tazobactam and vancomycin

PURPOSE

Results of a study to determine whether obesity is associated with acute kidney injury (AKI) among patients receiving combination therapy with piperacillin-tazobactam and vancomycin are reported.

METHODS

A retrospective, single-center cohort study of patients who received combination therapy for at least 48 hours was conducted using data from the University of Kentucky Center for Clinical and Translational Science's Enterprise Data Trust. Patients with chronic kidney disease, baseline creatinine clearance of less than 30 mL/min, cystic fibrosis, or missing height or weight information were excluded.

RESULTS

A total of 8,125 patients were included in the cohort. Among the variables evaluated, total body weight of 91 kg or more was the variable most predictive of AKI. Patients with a weight of 91 kg or higher were more likely than lower-weight patients to have diabetes (39% versus 21%, p < 0.00001), hypertension (64% versus 47%, p < 0.00001), and heart failure (15% versus 13%, p = 0.007). The median daily vancomcyin dose was lower in patients with a weight of less than 91 kg (2,000 mg versus 3,000 mg, p < 0.00001); however, weight-based doses were lower in patients weighing 91 kg or more (25.5 mg/kg/day versus 27.9 mg/kg/day, p < 0.00001). AKI was more common in patients weighing 91 kg or more (24% versus 18%, p < 0.00001; adjusted odds ratio, 1.46 [95% confidence interval, 1.28-1.66]).

CONCLUSION

Increased total body weight increased the rate of AKI among patients concurrently treated with piperacillin-tazobactam and vancomycin independent of clinically important confounders, with an important breakpoint occurring at 91 kg.

A review of citalopram dose restrictions in the treatment of neuropsychiatric disorders in older adults

Introduction

Neuropsychiatric disorders affect millions of older adults. Despite this, there are relatively few older adults included in clinical trials evaluating treatments for psychiatric disorders. Citalopram has been evaluated in older adults with neuropsychiatric disorders and has largely been found beneficial, making the 2011 US Food and Drug Administration (FDA) safety advisory on citalopram extremely impactful.

Methods

A literature search was completed using the PubMed database. Results were limited to clinical trials conducted in older adults that were published in English.

Results

Review of the literature confirms the efficacy of citalopram in depression, anxiety, depression associated with Parkinson disease, and behavioral and psychological symptoms of dementia. Additionally, no adverse cardiac outcomes have been described related to citalopram.

Discussion

The FDA's evidence for applying this safety advisory to citalopram is minimal and largely based on surrogate markers, such as the QTc interval rather than clinical and safety outcomes. Citalopram is known to increase the QTc, but this increase has not been linked to adverse cardiac outcomes. The evidence for efficacy and against adverse outcomes suggests that a reevaluation of the dosing restrictions in older adults with neuropsychiatric disorders is needed.

Utilizing the Patient Care Process to Minimize the Risk of Vancomycin-Associated Nephrotoxicity

Vancomycin-associated acute kidney injury (AKI) is a popular topic in the medical literature with few clear answers. While many studies evaluate the risk of AKI associated with vancomycin, few data are high quality and/or long in duration of follow-up. This review takes the clinician through an approach to evaluate a patient for risk of AKI. This evaluation should include patient assessment, antibiotic prescription, duration, and monitoring. Patient assessment involves evaluating severity of illness, baseline renal function, hypotension/vasopressor use, and concomitant nephrotoxins. Evaluation of antibiotic prescription includes evaluating the need for methicillin-resistant Staphylococcus aureus (MRSA) coverage and/or vancomycin use. Duration of therapy has been shown to increase the risk of AKI. Efforts to de-escalate vancomycin from the antimicrobial regimen, including MRSA nasal swabs and rapid diagnostics, should be used to lessen the likelihood of AKI. Adequate monitoring includes therapeutic drug monitoring, ongoing fluid status evaluations, and a continual reassessment of AKI risk. The issues with serum creatinine make the timely evaluation of renal function and diagnosis of the cause of AKI problematic. Most notably, concomitant piperacillin-tazobactam can increase serum creatinine via tubular secretion, resulting in higher rates of AKI being reported. The few studies evaluating the long-term prognosis of AKI in patients receiving vancomycin have found that few patients require renal replacement therapy and that the long-term risk of death is unaffected for patients surviving after the initial 28-day period.

Impact of piperacillin/tazobactam on nephrotoxicity in patients with Gram-negative bacteraemia

Piperacillin/tazobactam (TZP) has been associated with nephrotoxicity in patients receiving vancomycin. Its impact on nephrotoxicity in patients with Gram-negative bacteraemia (GNB) is unclear. This study evaluated the impact of TZP on nephrotoxicity in patients with GNB. This retrospective cohort included patients aged ≥18 years receiving ≥48 h of therapy for bacteraemia due to Escherichia coli, Pseudomonas aeruginosa, Enterobacter, Klebsiella, Acinetobacter or Stenotrophomonas maltophilia from 1/01/2008-8/31/2011. Patients with baseline serum creatinine (SCr) ≥3.5 mg/dL, polymicrobial infection or recurrent bacteraemia were excluded. Nephrotoxicity was defined as a ≥0.5 mg/dL increase in SCr or ≥50% increase from baseline for ≥2 consecutive days. Any variable demonstrating a 10% change in exposure effect was retained in the final model. All variables biologically reasonable causes of nephrotoxicity were also considered for inclusion. The median age of the cohort (n = 292) was 76 years; 38.0% had a cancer diagnosis and ICU residence was common (21.9%). There was no difference in nephrotoxicity incidence based on days of TZP received (0 days, 13.6%; 1-2 days, 14.7%; 3-4 days, 6.9%; ≥5 days, 16.7%; P = 0.71). In multivariable analysis, baseline SCr, total body weight and vasopressor use were independently associated with nephrotoxicity. Duration of TZP was not associated with nephrotoxicity in multivariable analysis (1-2 days, OR = 0.91, 95% CI 0.39-2.12; 3-4 days, OR = 0.48, 95% CI 0.10-2.46; ≥5 days, OR = 0.57, 95% CI 0.11-3.02). In this cohort of GNB patients, duration of TZP was not associated with nephrotoxicity.

Impact of total body weight on acute kidney injury in patients with gram-negative bacteremia

BACKGROUND

The impact of total body weight (TBW) on the development of acute kidney injury (AKI) associated with gram-negative bacteremia has not been previously evaluated.

METHODS

The cohort included 323 patients >/ = 18 years old with gram-negative bacteremia (1/1/2008-8/31/2011) who received >/ = 48 hours of antibiotics. We compared the incidence of AKI in patients with a TBW </ = 80kg vs. >80kg with a multivariable stepwise logistic regression adjusting for age >/ = 70 years, baseline serum creatinine of > 2.0 mg/dl, and receipt of a vasopressor. AKI was defined as an increase of 0.5 mg/dL or a > 50% increase from baseline for at least two consecutive days.

RESULTS

The cohort was 62% TBW </ = 80kg and 38% TBW >80kg. TBW >80kg patients had higher risk of AKI (24% vs. 9%, p < 0.001), which was significant in the multivariable analysis (OR 3.41, 95% CI 1.73-6.73). A baseline serum creatinine of > 2.0 mg/dl and vasopressor use were also independently associated with AKI.

CONCLUSIONS

TBW >80kg was associated with the development of AKI. However, the mechanism for this association is not clear.

Supervised Machine-Learning Reveals That Old and Obese People Achieve Low Dapsone Concentrations

The human species is becoming increasingly obese. Dapsone, which is extensively used across the globe for dermatological disorders, arachnid bites, and for treatment of several bacterial, fungal, and parasitic diseases, could be affected by obesity. We performed a clinical experiment, using optimal design, in volunteers weighing 44-150 kg, to identify the effect of obesity on dapsone pharmacokinetic parameters based on maximum-likelihood solution via the expectation-maximization algorithm. Artificial intelligence-based multivariate adaptive regression splines were used for covariate selection, and identified weight and/or age as predictors of absorption, systemic clearance, and volume of distribution. These relationships occurred only between certain patient weight and age ranges, delimited by multiple hinges and regions of discontinuity, not identified by standard pharmacometric approaches. Older and obese people have lower drug concentrations after standard dosing, but with complex patterns. Given that efficacy is concentration-dependent, optimal dapsone doses need to be personalized for obese patients.

Impact of total body weight on 30-day mortality in patients with gram-negative bacteremia

BACKGROUND

The impact of total body weight (TBW) on 30-day mortality associated with gram-negative bacteremia has not been previously evaluated.

METHODS

The cohort included 323 patients >/ = 18 years old with gram-negative bacteremia (1/1/2008-8/31/2011) who received >/ = 48 hours of antibiotics. We compared 30-day mortality of TBW <70 kg vs. >/ = 70 kg with a multivariable stepwise logistic regression adjusting for age >/ = 70 years, cancer diagnosis, and Pitt bacteremia score of >/ = 4.

RESULTS

The cohort was 57% TBW >/ = 70 kg and 43% TBW <70 kg. TBW >/ = 70 kg patients had lower 30-day mortality (11.0% vs. 16.3%), which was significant in the multivariable analysis (OR 0.45, 95% CI 0.21-0.97). Cancer and Pitt bacteremia score >/ = 4 were also independently associated with 30-day mortality. TBW was no longer significant when TBW <50 kg patients were excluded.

CONCLUSION

TBW >/ = 70 kg was associated with an improved 30-day mortality; however, the high mortality rates for patients with a TBW < 50 kg is responsible for this association.

Can Pharmacokinetic and Pharmacodynamic Principles Be Applied to the Treatment of Multidrug-Resistant Acinetobacter?

OBJECTIVE:

To discuss treatment options that can be used for treatment of Acinetobacter infections.

DATA SOURCES:

A MEDLINE search (1966-November 2010) was conducted to identify English-language literature on pharmacotherapy of Acinetobacter and the bibliographies of pertinent articles. Programs and abstracts from infectious diseases meetings were also searched. Search terms included Acinetobacter, multidrug resistance, pharmacokinetics, pharmacodynamics, Monte Carlo simulation, nosocomial pneumonia, carbapenems, polymyxins, sulbactam, aminoglycosides, tetracyclines, tigecycline, rifampin, and fluoroquinolones.

DATA SELECTION AND DATA EXTRACTION:

All articles were critically evaluated and all pertinent information was included in this review.

DATA SYNTHESIS:

Multidrug resistant (MDR) Acinetobacter, defined as resistance to 3 or more antimicrobial classes, has increased over the past decade. The incidence of carbapenem-resistant Acinetobacter is also increasing, leading to an increased use of dose optimization techniques and/or alternative antimicrobials, which is driven by local susceptibility patterns. However, Acinetobacter infections that are resistant to all commercially available antibiotics have been reported. General principles are available to guide dose optimization of aminoglycosides, β-lactams, fluoroquinolones, and tigecycline for infections due to gram-negative pathogens. Unfortunately, data specific to patients with Acinetobacter infections are limited. Recent pharmacokinetic-pharmacodynamic information has shed light on colistin dosing. The dilemma with colistin is its concentration-dependent killing, which makes once-daily dosing seem like an attractive option, but its short postantibiotic effect limits a clinician's ability to extend the dosing interval. Localized delivery of antimicrobials is also an attractive option due to the ability to increase drug concentration at the infection site while minimizing systemic adverse events, but more data are needed regarding this approach.

CONCLUSIONS:

Increased reliance on dosage optimization, combination therapy, and localized delivery of antimicrobials are methods to pursue positive clinical outcomes in MDR Acinetobacter infections since novel antimicrobials will not be available for several years. Well-designed clinical trials with MDR Acinetobacter are needed to define the best treatment options for these patients.

Dosing strategies to optimize currently available anti-MRSA treatment options (Part 1: IV options)

INTRODUCTION

Methicillin-resistant Staphylococcus aureus (MRSA) continues to be a predominant pathogen resulting in significant morbidity and mortality. Optimal dosing of anti-MRSA agents is needed to help prevent the development of antimicrobial resistance and to increase the likelihood of a favorable clinical outcome. Areas covered: This review summarizes the available data for antimicrobials routinely used for MRSA infections that are not administered orally or topically. We make recommendations and highlight the current gaps in the literature. A PubMed (1966 - Present) search was performed to identify relevant literature for this review. Expert commentary: Improvements in MIC determination and therapeutic drug monitoring are needed to fully implement individualized dosing that optimizes antimicrobial pharmacodynamics.Additional data will become available for these agents in regards to effectiveness for severe MRSA infections and pharmacokinetic data for special patient populations.

Infectious Diseases: Pharmacologic Treatment Options for Nosocomial Pneumonia Involving Methicillin-Resistant Staphylococcus aureus

Objective:

To discuss current and potential treatment options for nosocomial pneumonia due to methicillin-resistant Staphylococcus aureus (MRSA).

Data Sources:

A MEDLINE search (1966–January 2007) was conducted to identify English-language literature on pharmacotherapy of nosocomial pneumonia and the bibliographies of pertinent articles. Programs and abstracts from infectious disease meetings were also searched. Search terms included MRSA, nosocomial pneumonia, pulmonary infections, vancomycin, quinupristin/dalfopristin, linezolid, daptomycin, tigecycline, dalbavancin, oritavancin, and ceftobiprole.

Data Selection and Data Extraction:

All articles were critically evaluated and all pertinent information was included in this review.

Data Synthesis:

Vancomycin has been the drug of choice for MRSA infections for many years. Recent data suggest that linezolid may be superior to vancomycin in the treatment of MRSA nosocomial pneumonia. However, there are limitations to the available data. Therefore, prospective, randomized studies are needed before linezolid is recommended as the preferred first-line therapy. Other approved agents for nosocomial MRSA infections, such as quinupristin/dalfopristin and daptomycin, should not be used in the treatment of MRSA pneumonia, as they were inferior in clinical trials. Tigecycline has excellent activity against MRSA in vitro, but should not be routinely used for the treatment of MRSA pneumonia, as clinical data are lacking. In a Phase III clinical trial, an anti-MRSA cephalosporin, ceftobiprole, is being evaluated for effectiveness against nosocomial pneumonia. Investigational glycopeptides may eventually have a role in the treatment of nosocomial pneumonia, but data are currently lacking.

Conclusions:

Vancomycin is still the drug of choice for treatment of MRSA pneumonia, and linezolid should be used as an alternative agent. Linezolid should carry strong consideration for patients with vancomycin-induced nephrotoxicity or a documented lack of response to vancomycin. Tigecycline and investigational agents with activity against MRSA may be future options for nosocomial pneumonia due to MRSA.

A prospective observational cohort study in primary care practices to identify factors associated with treatment failure in Staphylococcus aureus skin and soft tissue infections

Background

The incidence of outpatient visits for skin and soft tissue infections (SSTIs) has substantially increased over the last decade. The emergence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has made the management of S. aureus SSTIs complex and challenging. The objective of this study was to identify risk factors contributing to treatment failures associated with community-associated S. aureus skin and soft tissue infections SSTIs.

Methods

This was a prospective, observational study among 14 primary care clinics within the South Texas Ambulatory Research Network. The primary outcome was treatment failure within 90 days of the initial visit. Univariate associations between the explanatory variables and treatment failure were examined. A generalized linear mixed-effect model was developed to identify independent risk factors associated with treatment failure.

Results

Overall, 21% (22/106) patients with S. aureus SSTIs experienced treatment failure. The occurrence of treatment failure was similar among patients with methicillin-resistant S. aureus and those with methicillin-susceptible S. aureus SSTIs (19 vs. 24%; p = 0.70). Independent predictors of treatment failure among cases with S. aureus SSTIs was a duration of infection of ≥7 days prior to initial visit [aOR, 6.02 (95% CI 1.74–19.61)] and a lesion diameter size ≥5 cm [5.25 (1.58–17.20)].

Conclusions

Predictors for treatment failure included a duration of infection for ≥7 days prior to the initial visit and a wound diameter of ≥5 cm. A heightened awareness of these risk factors could help direct targeted interventions in high-risk populations.

Fractal Geometry-Based Decrease in Trimethoprim-Sulfamethoxazole Concentrations in Overweight and Obese People

Trimethoprim-sulfamethoxazole (TMP-SMX) is one of the most widely drugs on earth. The World Health Organization recommends it as an essential basic drug for all healthcare systems. Dosing is inconsistently based on weight, assuming linear relationships. Given that obesity is now a global "pandemic" it is vital that we evaluate the effect of obesity on trimethoprim-sulfamethoxazole concentrations. We conducted a prospective clinical experiment based on optimized design strategies and artificial intelligence algorithms and found that weight and body mass index (BMI) had a profound effect on drug clearance and volume of distribution, and followed nonlinear fractal geometry-based relationships. The findings were confirmed by demonstrating decreased TMP-SMX peak and area under the concentration-time curves in overweight patients based on standard regression statistics. The nonlinear relationships can now be used to identify new TMP-SMX doses in overweight and obese patients for each of the infections caused by the >60 pathogens for which the drug is indicated.

Evolving Larger: Dosing Anti-Tuberculosis (TB) Drugs in an Obese World

Current clinical practice guidelines recommend dosing anti-tuberculosis drugs according to ideal body weight and provide dosing caps for most first-line agents. However, this recommendation may be placing corpulent patients with tuberculosis at risk as increased total body weight is associated with an increased risk of clinical failure. Patients with diabetes are at an increased risk of developing tuberculosis and typically weigh more than patients with tuberculosis alone. All these factors in-combination stress the importance of evaluating the effect of weight on the pharmacokinetics of first-line anti-tuberculosis drugs. Multiple studies suggest the use of total body weight based dosing for rifampin. Less data are available for pyrazinamide and ethambutol, but both appear to be candidates for total body weight based dosing. The study evaluating levofloxacin concluded that no adjustment is required. However, the larger variability in obese patients is concerning as to whether "one size fits all" dosing is optimal for levofloxacin. The vast majority of the isoniazid's pharmacokinetic variability is due to NAT2*4 status. However, more extensive analysis of slow and fast metabolizers is needed to determine the effect of weight within each subgroup. Moxifloxacin does not appear to be affected by weight, but doses of at least 800 mg are likely needed to optimize its pharmacokinetic/pharmacodynamic target attainment. Future pharmacokinetic evaluations should focus on recruiting a wide range of patient weights. These analyses should take advantage of the full weight distribution instead of arbitrarily dichotomizing patients into obese vs. non-obese persons. A subsequent evaluation of the safety and effectiveness of optimized dosing regimens is needed.

Low-Molecular-Weight Heparin Prophylaxis Dosing

Objective. To evaluate the pharmacokinetic, safety, and effectiveness data of dosing low-molecular-weight heparins (LMWHs) for prophylaxis of venous thromboembolic events (VTEs) in obese people. Data Sources. A PubMed search (1966 to September 2015) was performed of published English articles using the following keywords: low-molecular-weight heparin, prophylaxis, and obesity. Study Selection and Data Extraction. In all, a total of 11 articles were included in this review. The search was conducted to identify pharmacokinetic studies, clinical trials (phases I-IV), or retrospective evaluations of the impact of weight and/or obesity on anti-Xa levels as well as the safety and effectiveness of LMWHs used for VTE prophylaxis. Data Synthesis. The vast majority of the available data focus on enoxaparin. Pharmacokinetic, effectiveness, and safety data all support increased enoxaparin dosing in obese patients. However, the optimal adjustment remains uncertain. For now, we recommend using 40 mg twice daily as the data for effectiveness use this regimen. Dalteparin dosing should not be adjusted in class I-II obese (body mass index 30.0-39.9 kg/m2) patients. Data regarding the impact of class III obesity (body mass index ≥40 kg/m2) on dalteparin effectiveness is needed. Total body weight dosing of tinzaparin can be used to optimize anti-Xa levels, but safety and effectiveness data are needed before weight-based tinzaparin dosing is routine medical practice for obese patients. Conclusions. The data regarding dosing of LMWHs for VTE prophylaxis are quite limited. High-quality studies are needed to help optimize dosing for obese adults requiring LMWH prophylaxis.

Treatment of community-acquired pneumonia

Community-acquired pneumonia is the sixth leading cause of death in the USA. Adherence to the 2007 Infectious Diseases Society of America/American Thoracic Society community-acquired pneumonia guidelines has been associated with improved clinical outcomes. However, choice between guideline-recommended treatments is at the discretion of the prescribing clinician. This review is intended to discuss the characteristics of these treatment options including dosing frequency, dose adjustment for renal/hepatic dysfunction, serious/common adverse events, drug interactions, lung penetration, pharmacokinetic-pharmacodynamic target and effect of obesity to help guide antimicrobial selection. An increasing portion of patients are receiving expanded empiric coverage for methicillin-resistant Staphylococcus aureus as recommended by the American Thoracic Society and Infectious Diseases Society of America for healthcare-associated pneumonia. However, this expanded coverage may not be achieving the desired improvements in clinical outcomes. We expect this increasingly diverse spectrum of patients with pneumonia to eventually result in the merger of these two guidelines to include all patients with pneumonia.

Profile of tedizolid phosphate and its potential in the treatment of acute bacterial skin and skin structure infections

Tedizolid phosphate is the first once-daily oxazolidinone approved by the United States Food and Drug Administration for the treatment of acute bacterial skin and skin structure infections (ABSSSI). It is more potent in vitro than linezolid against methicillin-resistant Staphylococcus aureus (MRSA) and other gram-positive pathogens causing ABSSSI, even retaining activity against some linezolid-resistant strains. Tedizolid is approximately 90% protein bound, leading to lower free-drug concentrations than linezolid. The impact of the effect of food, renal or hepatic insufficiency, or hemodialysis on tedizolid's pharmacokinetic have been evaluated, and no dosage adjustment is needed in these populations. In animal and clinical studies, tedizolid's effect on bacterial killing is optimized by the free-drug area under the curve to minimum inhibitory concentration ratio (fAUC/MIC). The 200 mg once-daily dose is able to achieve the target fAUC/MIC ratio in 98% of simulated patients. Two Phase III clinical trials have demonstrated the noninferiority of tedizolid 200 mg once daily for 6 days to linezolid 600 mg twice daily for 10 days. In vitro, animal, and clinical studies have failed to demonstrate that tedizolid inhibits monoamine oxidase to a clinically relevant extent. Tedizolid has several key advantages over linezolid including once daily dosing, decreased treatment duration, minimal interaction with serotonergic agents, possibly associated with less adverse events associated with the impairment of mitochondrial protein synthesis (eg, myelosuppression, lactic acidosis, and peripheral/optic neuropathies), and retains in vitro activity against linezolid-resistant gram-positive bacteria. Economic analyses with tedizolid are needed to describe the cost-effectiveness of this agent compared with other options used for ABSSSI, particularly treatment options active against MRSA.

Impact of empiric weight-based vancomycin dosing on nephrotoxicity and mortality in geriatric patients with methicillin-resistant Staphylococcus aureus bacteraemia

WHAT IS KNOWN AND OBJECTIVE

Few studies have evaluated the effect of vancomycin dosing on the health outcomes in geriatric patients. Data are needed to determine whether higher vancomycin dosing strategies are more effective in geriatric patients and/or lead to excessive rates of adverse events.

METHODS

This study used a subset of patients aged ≥65 years from a multicentre, retrospective, cohort study of methicillin-resistant Staphylococcus aureus (MRSA) bacteraemia. Patients received ≥ 48 h of empiric vancomycin between 1 July 2002 and 30 June 2008. We compared the incidence of nephrotoxicity and in-hospital mortality in patients who received guideline-recommended dosing (at least 15 mg/kg/dose) to patients who received lower dosing. Multivariable generalized mixed-effect models were constructed to determine independent risk factors for nephrotoxicity and in-hospital mortality.

RESULTS AND DISCUSSION

Half of the cohort (46% of 92 patients) received guideline-recommended dosing. Empiric use of weight-based dosing did increase the percentage of patients achieving a vancomycin trough ≥ 15 mg/L (57% vs. 42%). Nephrotoxicity occurred in 32% of patients and 26% died during their hospitalization. Guideline-recommended dosing was not associated with significant changes in nephrotoxicity (OR 1·13; 95% CI 0·40-3·19) or in-hospital mortality (OR 1·14; 95% CI 0·41-3·18) in the multivariable analysis.

WHAT IS NEW AND CONCLUSION

In this study of geriatric patients, guideline-recommended dosing was not associated with significant changes in nephrotoxicity or mortality. As 40% of the patients who received guideline-recommended dosing failed to achieve a target vancomycin trough of ≥ 15 mg/L, future studies should focus on dosing strategies to increase target attainment rate.

Therapy duration and long-term outcomes in extra-pulmonary tuberculosis

BACKGROUND

Tuberculosis is classified as either pulmonary or extra-pulmonary (EPTB). While much focus has been paid to pulmonary tuberculosis, EPTB has received scant attention. Moreover, EPTB is viewed as one wastebasket diagnosis, as "the other" which is not pulmonary.

METHODS

This is a retrospective cohort study of all patients treated for EPTB in the state of Texas between January 2000 and December 2005, who had no pulmonary disease. Clinical and epidemiological factors were abstracted from electronic records of the Report of Verified Case of Tuberculosis. The long-term outcome, which is death by December 2011, was established using the Social Security Administration Death Master File database. Survival in EPTB patients was compared to those with latent tuberculosis, as well as between different types of EPTB, using Cox proportional hazard models. A hybrid of the machine learning method of classification and regression tree analyses and standard regression models was used to identify high-order interactions and clinical factors predictive of long-term all-cause mortality.

RESULTS

Four hundred and thirty eight patients met study criteria; the median study follow-up period for the cohort was 7.8 (inter-quartile range 6.0-10.1) years. The overall all-cause mortality rate was 0.025 (95% confidence interval [CI]: 0.021-0.030) per 100 person-year of follow-up. The significant predictors of poor long-term outcome were age (hazard ratio [HR] for each year of age-at-diagnosis was 1.05 [CI: 1.04-1.06], treatment duration, type of EPTB and HIV-infection (HR = 2.16; CI: 1.22, 3.83). Mortality in genitourinary tuberculosis was no different from latent tuberculosis, while meningitis had the poorest long-term outcome of 46.2%. Compared to meningitis the HR for death was 0.50 (CI: 0.27-0.91) for lymphatic disease, 0.42 (CI: 0.21-0.81) for bone/joint disease, and 0.59 (CI: 0.27-1.31) for peritonitis. The relationship between mortality and therapy duration for each type of EPTB was a unique "V" shaped curve, with the lowest mortality observed at different therapy durations for each, beyond which mortality increased.

CONCLUSIONS

EPTB is comprised of several different diseases with different outcomes and durations of therapy. The "V" shaped relationship between therapy duration and outcome leads to the hypothesis that longer duration of therapy may lead to higher patient mortality.

Evaluation of chemotherapy-induced severe myelosuppression incidence in obese patients with capped dosing

PURPOSE

Clinicians typically cap an obese patient's chemotherapy regimen as a result of concern for excessive toxicity, without adequate clinical evidence. The purpose of this study was to evaluate the incidence of grade 3 or 4 myelosuppression in obese patients versus nonobese patients with capped dosing on the basis of body surface area (BSA).

METHODS

A retrospective chart review was conducted comparing obese patients (body mass index [BMI] ≥ 30 kg/m(2)) with capped dosing who received capped chemotherapy doses at a BSA of 2.2 m(2) with nonobese (BMI < 25 kg/m(2)) patients with lung, colorectal, or hormone-refractory prostate cancer.

RESULTS

Forty-one obese patients with capped dosing and 244 nonobese patients were included. The obese patient group received on average significantly more cycles of chemotherapy (6 v 4 cycles) compared with the nonobese group. The overall incidence of any chemotherapy-related toxicity was 34% in the obese patient group, compared with 42% in the nonobese patient group (P = .356). The incidence of grade 3 or 4 myelosuppression was lower, but not statistically significant, in obese patients with capped dosing compared with the nonobese patient group (22% v 27%; P = .493).

CONCLUSIONS

Overall, obese patients with capped dosing experienced a lower incidence of severe myelosuppression and tolerated more cycles of chemotherapy compared with nonobese patients. The better tolerability of chemotherapy in obese patients with capped dosing suggests that there is room to increase the dose in obese patients above the nationally recognized BSA cap of 2.0 m(2), especially in early-stage lung or colon cancers in which the intention of treatment is curative.

Empiric guideline-recommended weight-based vancomycin dosing and nephrotoxicity rates in patients with methicillin-resistant Staphylococcus aureus bacteremia: a retrospective cohort study

Background

Previous studies have established a correlation between vancomycin troughs and nephrotoxicity. However, data are currently lacking regarding the effect of guideline-recommended weight-based dosing on nephrotoxicity in methicillin-resistant Staphylococcus aureus bacteremia (MRSAB).

Methods

Adults who were at least 18 years of age with methicillin-resistant Staphylococcus aureus bacteremia and received of empiric vancomycin therapy for at least 48 hours (01/07/2002 and 30/06/2008) were included in this multicenter, retrospective cohort study. The association between guideline-recommended, weight-based vancomycin dosing (at least 15 mg/kg/dose) and nephrotoxicity (increase in serum creatinine (SCr) by more than 0.5 mg/dl or at least a 50% increase from baseline on at least two consecutive laboratory tests) was evaluated. Potential independent associations were evaluated using a multivariable general linear mixed-effect model.

Results

Overall, 23% of patients developed nephrotoxicity. Thirty-four percent of the 337 patients who met study criteria received weight-based dosing. The cohort was composed of 69% males with a median age of 55 years. The most common sources of MRSAB included skin/soft tissue (32%), catheter-related bloodstream bacteremia (20%), pulmonary (18%). Eighty-six percent of patients received twice daily dosing. Similar rates of nephrotoxicity were observed regardless of the receipt of guideline-recommended dosing (22% vs. 24%, OR 0.91 [95% CI 0.53-1.56]). This finding was confirmed in the multivariable analysis (OR 1.52 [95% CI 0.75-3.08]). Independent predictors of nephrotoxicity were (OR, 95% CI) vancomycin duration of greater than 15 days (3.36, 1.79-6.34), weight over 100 kg (2.74, 1.27-5.91), Pitt bacteremia score of 4 or greater (2.73, 1.29-5.79), vancomycin trough higher than 20 mcg/ml (2.36, 1.07-5.20), and age over 52 years (2.10, 1.08-4.08).

Conclusions

Over one out of five patients in this study developed nephrotoxicity while receiving vancomycin for MRSAB. The receipt of guideline-recommended, weight-based vancomycin was not an independent risk factor for the development of nephrotoxicity.

Empiric guideline-recommended weight-based vancomycin dosing and mortality in methicillin-resistant Staphylococcus aureus bacteremia: a retrospective cohort study

BACKGROUND

No studies have evaluated the effect of guideline-recommended weight-based dosing on in-hospital mortality of patients with methicillin-resistant Staphylococcus aureus bacteremia.

METHODS

This was a multicenter, retrospective, cohort study of patients with methicillin-resistant Staphylococcus aureus bacteremia receiving at least 48 hours of empiric vancomycin therapy between 01/07/2002 and 30/06/2008. We compared in-hospital mortality for patients treated empirically with weight-based, guideline-recommended vancomycin doses (at least 15 mg/kg/dose) to those treated with less than 15 mg/kg/dose. We used a general linear mixed multivariable model analysis with variables identified a priori through a conceptual framework based on the literature.

RESULTS

A total of 337 patients who were admitted to the three hospitals were included in the cohort. One-third of patients received vancomycin empirically at the guideline-recommended dose. Guideline-recommended dosing was not associated with in-hospital mortality in the univariable (16% vs. 13%, OR 1.26 [95%CI 0.67-2.39]) or multivariable (OR 0.71, 95%CI 0.33-1.55) analysis. Independent predictors of in-hospital mortality were ICU admission, Pitt bacteremia score of 4 or greater, age 53 years or greater, and nephrotoxicity.

CONCLUSIONS

Empiric use of weight-based, guideline-recommended empiric vancomycin dosing was not associated with reduced mortality in this multicenter study.

Empiric therapy for gram-negative pathogens in nosocomial and health care-associated pneumonia: starting with the end in mind

Nosocomial pneumonia is a major cause of morbidity and mortality for hospitalized patients. Antimicrobial resistance is increasing, creating a strain between ensuring the provision of adequate empiric therapy and slowing the development of antimicrobial resistance. Excessive antimicrobial therapy places patients are at greater risk of drug interactions, adverse events, and superinfections. Ways to maximize adequate empiric therapy include (1) categorizing each patient's risk of being infected with a multidrug-resistant pathogen and knowledge of local susceptibility patterns, (2) de-escalating antimicrobial therapy to decrease the rates of superinfections such as Clostridium difficile, and (3) limiting the duration of therapy to decrease the likelihood of adverse events, drug interactions, and antimicrobial resistance. Pharmacodynamically enhanced dosing regimens also have the potential to improve clinical outcomes and slow the development of antimicrobial resistance. Drugs whose killing is optimized by the percentage time above the minimum inhibitory concentration (MIC), such as beta-lactams, can be given by continuous or extended infusion to provide superior pharmacodynamic (PD) target attainment rates compared with traditional regimens. Drugs whose killing is optimized with a high-peak plasma concentration to MIC ratio (eg, aminoglycosides) should be administered once daily to maximize the likelihood of achieve optimal target attainment rates. Drugs whose killing is optimized by the ratio of the area under the curve (AUC) to MIC ratio (eg, fluoroquinolones) depend on the total daily dose as opposed to the dosing schedule or infusion time. Determining the optimal drug dosing schedules for obese patients remains critical because these patients have may have significantly increased volumes of distribution and clearance rates compared to normal weight patients. Optimizing the use of current antimicrobials is paramount to ensure quality treatment options are available, given the lack of gram-negative antimicrobials in the pipeline.