Pooled Population Pharmacokinetic Analysis and Dose Recommendations for Ciprofloxacin in Intensive Care Unit Patients with Obesity.

Recent studies have explored the influence of obesity and critical illness on ciprofloxacin pharmacokinetics. However, variation across the subpopulation of individuals with obesity admitted to the intensive care unit (ICU) with varying renal function remains unexamined. This study aims to characterize ciprofloxacin pharmacokinetics in ICU patients with obesity and provide dose recommendations for this special population. Individual patient data of 34 ICU patients with obesity (BMI >30 kg/m2) from four studies evaluating ciprofloxacin pharmacokinetics in ICU patients were pooled and combined with data from a study involving 10 individuals with obesity undergoing bariatric surgery. All samples were collected after intravenous administration. Non-linear mixed effects modeling and simulation were used to develop a population pharmacokinetic model and describe ciprofloxacin exposure in plasma. Model-based dose evaluations were performed using a pharmacokinetic/pharmacodynamic target of AUC/MIC >125. The data from patients with BMI ranging from 30.2 to 58.1 were best described by a two-compartment model with first-order elimination and a proportional error model. The inclusion of Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) as a covariate on clearance reduced inter-individual variability from 57.3% to 38.5% (P < .001). Neither body weight nor ICU admission significantly influenced clearance or volume of distribution. Renal function is a viable predictor for ciprofloxacin clearance in ICU patients with obesity, while critical illness and body weight do not significantly alter clearance. As such, body weight and critical illness do not need to be accounted for when dosing ciprofloxacin in ICU patients with obesity. Individuals with CKD-EPI >60 mL/min/1.73 m2 may require higher dosages for the treatment of pathogens with minimal inhibitory concentration ≥0.25 mg/L.

Performance of ChatGPT on Factual Knowledge Questions Regarding Clinical Pharmacy.

ChatGPT is a language model that was trained on a large dataset including medical literature. Several studies have described the performance of ChatGPT on medical exams. In this study, we examine its performance in answering factual knowledge questions regarding clinical pharmacy. Questions were obtained from a Dutch application that features multiple-choice questions to maintain a basic knowledge level for clinical pharmacists. In total, 264 clinical pharmacy-related questions were presented to ChatGPT and responses were evaluated for accuracy, concordance, quality of the substantiation, and reproducibility. Accuracy was defined as the correctness of the answer, and results were compared to the overall score by pharmacists over 2022. Responses were marked concordant if no contradictions were present. The quality of the substantiation was graded by two independent pharmacists using a 4-point scale. Reproducibility was established by presenting questions multiple times and on various days. ChatGPT yielded accurate responses for 79% of the questions, surpassing pharmacists' accuracy of 66%. Concordance was 95%, and the quality of the substantiation was deemed good or excellent for 73% of the questions. Reproducibility was consistently high, both within day and between days (>92%), as well as across different users. ChatGPT demonstrated a higher accuracy and reproducibility to factual knowledge questions related to clinical pharmacy practice than pharmacists. Consequently, we posit that ChatGPT could serve as a valuable resource to pharmacists. We hope the technology will further improve, which may lead to enhanced future performance.

Poor performance of ChatGPT in clinical rule-guided dose interventions in hospitalized patients with renal dysfunction.

PURPOSE: Clinical decision support systems (CDSS) are used to identify drugs with potential need for dose modification in patients with renal impairment. ChatGPT holds the potential to be integrated in the electronic health record (EHR) system to give such dosing advices. In this study, we aim to evaluate the performance of ChatGPT in clinical rule-guided dose interventions in hospitalized patients with renal impairment. METHODS: This cross-sectional study was performed at Tergooi Medical Center, the Netherlands. CDSS alerts regarding renal dysfunction were collected from the electronic health record (EHR) during a 2-week period and were presented to ChatGPT and an expert panel. Alerts were presented with and without patient variables. To evaluate the performance, suggested medication interventions were compared. RESULTS: In total, 172 CDDS alerts were generated for 80 patients. Indecisive responses by ChatGPT to alerts were excluded. For alerts presented without patient variables, ChatGPT provided "correct and identical" responses to 19.9%, "correct and different" responses to 26.7%, and "incorrect responses to 53.4% of the alerts. For alerts including patient variables, ChatGPT provided "correct and identical" responses to 16.7%, "correct and different" responses to 16.0%, and "incorrect responses to 67.3% of the alerts. Accuracy was better for newer drugs such as direct oral anticoagulants. CONCLUSION: The performance of ChatGPT in clinical rule-guided dose interventions in hospitalized patients with renal dysfunction was poor. Based on these results, we conclude that ChatGPT, in its current state, is not appropriate for automatic integration into our EHR to handle CDSS alerts related to renal dysfunction.

Diagnosis-linked antibiotic prescribing quality indicators: demonstrating feasibility using practice-based routine primary care data, reliability, validity and their potential in antimicrobial stewardship.

BACKGROUND: Quality indicators (QIs) can be used to obtain valuable insights into prescribing quality. Five quantitative and nine diagnosis-linked QIs, aiming to provide general practitioners (GP) with feedback on their antibiotic prescribing quantity and quality, were previously developed and evaluated in a controlled study. OBJECTIVE: To confirm, in a larger non-controlled study, the feasibility of using routinely collected and extracted electronic patient records to calculate the diagnosis-linked QI outcomes for antibiotic prescribing, and their reliability and validity. METHODS: Retrospective study involving 299 Dutch general practices using routine care data (2018-2020). QIs describe total antibiotic and subgroup prescribing, prescribing percentages and first-choice prescribing for several clinical diagnoses. Practice variation in QI outcomes, inter-QI outcome correlations and sensitivity of QI outcomes to pandemic-induced change were determined. RESULTS: QI outcomes were successfully obtained for 278/299 practices. With respect to reliability, outcomes for 2018 and 2019 were comparable, between-practice variation in outcomes was similar to the controlled pilot, and inter-QI outcome correlations were as expected, for example: high prescribing of second choice antibiotics with low first-choice prescribing for clinical diagnoses. Validity was confirmed by their sensitivity to pandemic-induced change: total antibiotic prescribing decreased from 282 prescriptions/1000 registered patients in 2018 to 216 in 2020, with a decrease in prescribing percentages for upper and lower respiratory infections, from 26% to 18.5%, and from 28% to 16%. CONCLUSIONS: This study confirmed the fit-for-purpose (feasibility, reliability and validity) of the antibiotic prescribing QIs (including clinical diagnosis-linked ones) using routinely registered primary health care data as a source. This feedback can therefore be used in antibiotic stewardship programmes to improve GPs' prescribing routines.

Home-based monitoring of ovulation to time frozen embryo transfers in the Netherlands (Antarctica-2): an open-label, nationwide, randomised, non-inferiority trial.

BACKGROUND: The growing field of assisted reproductive techniques, including frozen-thawed embryo transfer (FET), should lead the way to the best sustainable health care without compromising pregnancy chances. Correct timing of FET is crucial to allow implantation of the thawed embryo. Nowadays, timing based on hospital-controlled monitoring of ovulation in the natural cycle of a woman is the preferred strategy because of the assumption of favourable fertility prospects. However, home-based monitoring is a simple method to prevent patient travel and any associated environmental concerns. We compared ongoing pregnancy rates after home-based monitoring versus hospital-controlled monitoring with ovulation triggering. METHODS: This open-label, multicentre, randomised, non-inferiority trial was undertaken in 23 hospitals and clinics in the Netherlands. Women aged between 18 and 44 years with a regular ovulatory menstrual cycle were randomly assigned in a 1:1 ratio via a web-based randomisation program to home-based monitoring or hospital-controlled monitoring. Those who analysed the data were masked to the groups; those collecting the data were not. All endpoints were analysed by intention to treat and per protocol. Non-inferiority was established when the lower limit of the 90% CI exceeded -4%. This study was registered at the Dutch Trial Register (Trial NL6414). FINDINGS: 1464 women were randomly assigned between April 10, 2018, and April 13, 2022, with 732 allocated to home-based monitoring and 732 to hospital-controlled monitoring. Ongoing pregnancy occurred in 152 (20·8%) of 732 in the home-based monitoring group and in 153 (20·9%) of 732 in the hospital-controlled monitoring group (risk ratio [RR] 0·99 [90% CI 0·81 to 1·22]; risk difference [RD] -0·14 [90% CI -3·63 to 3·36]). The per-protocol analysis confirmed non-inferiority (152 [21·0%] of 725 vs 153 [21·0%] of 727; RR 1·00 (90% CI 0·81 to 1·23); RD -0·08 [90% CI -3·60 to 3·44]). INTERPRETATION: Home-based monitoring of ovulation is non-inferior to hospital-controlled monitoring of ovulation to time FET. FUNDING: The Dutch Organisation for Health Research and Development.

Assessment of drug-related problems at the emergency department in older patients living with frailty: pharmacist-led medication reviews within a geriatric care team.

BACKGROUND: Older patients are vulnerable to experiencing drug related problems (DRPs), which may result in emergency department (ED) visits. However, it is not standard practice to conduct medications reviews during ED visit. The aim of this study was to assess the number of DRPs in older patients living with frailty at the ED, identified through pharmacist-led medication reviews within a geriatric care team, and to determine the acceptance rate of pharmacists' recommendations among hospital physicians and general practitioners or elderly care specialists. METHODS: A retrospective observational study was performed in patients ≥ 70 years living with frailty at the ED at Tergooi Medical Center. Pharmacist-led medication reviews were conducted to identify and classify DRPs as part of a larger geriatric assessment. The acceptance rate of given recommendations was determined during follow-up. RESULTS: A total of 356 ED visits were included. The mean (standard deviation, SD) age of patients was 83 (6.8) years. About 76% of patients had at least one DRP. In total, 548 DRPs were identified with a mean of 1.5 DRP (SD 1.3) per patient. The acceptance rate of medication recommendations in admitted patients was 55%, and 32% among general practitioners/elderly care specialists in discharged patients. CONCLUSIONS: Pharmacist-led medication reviews as part of a geriatric care team identified DRPs in 76% of older patients living with frailty at the ED. The acceptance rate was substantially higher in admitted patients compared to discharged patients.

Women on diuretics have a higher risk of hospital admission because of hyponatremia than men.

PURPOSE: Recent studies suggest that women are more susceptible to diuretic-induced hyponatremia resulting in hospital admission than men. The aim of this study was to confirm whether these sex differences in hyponatremia-related hospital admissions in diuretic users remain after adjusting for several confounding variables such as age, dose, and concurrent medication. METHODS: In a case-control design nested in diuretic users, cases of hyponatremia associated hospital admissions between 2005 and 2017 were identified from the PHARMO Data Network. Cases were 1:10 matched to diuretic users as controls. Odds ratios (OR) with 95%CIs were calculated for women versus men and adjusted for potential confounders (age, number of diuretics, other hyponatremia-inducing drugs, chronic disease score) using unconditional logistic regression analysis. A subgroup analysis was performed for specific diuretic groups (thiazides, loop diuretics and aldosterone antagonists). RESULTS: Women had a statistically significantly higher risk of a hospital admission associated with hyponatremia than men while using diuretics (OR 1.86, 95%CI 1.64-2.11). Adjusting for the potential confounders resulted in an increased risk for women compared to men (ORadj 2.65, 95% CI 2.31-3.04). This higher risk in women was also seen in the three subgroup analyses after adjustment. CONCLUSION: Our findings show a higher risk of hyponatremia-related hospital admission in women than men while using diuretics. Further research is needed to understand the underlying mechanism of this sex difference to be able to provide sex-specific recommendations.

The 2021 Dutch Working Party on Antibiotic Policy (SWAB) guidelines for empirical antibacterial therapy of sepsis in adults.

BACKGROUND: The Dutch Working Party on Antibiotic Policy (SWAB) in collaboration with relevant professional societies, has updated their evidence-based guidelines on empiric antibacterial therapy of sepsis in adults. METHODS: Our multidisciplinary guideline committee generated ten population, intervention, comparison, and outcome (PICO) questions relevant for adult patients with sepsis. For each question, a literature search was performed to obtain the best available evidence and assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system. The quality of evidence for clinically relevant outcomes was graded from high to very low. In structured consensus meetings, the committee formulated recommendations as strong or weak. When evidence could not be obtained, recommendations were provided based on expert opinion and experience (good practice statements). RESULTS: Fifty-five recommendations on the antibacterial therapy of sepsis were generated. Recommendations on empiric antibacterial therapy choices were differentiated for sepsis according to the source of infection, the potential causative pathogen and its resistance pattern. One important revision was the distinction between low, increased and high risk of infection with Enterobacterales resistant to third generation cephalosporins (3GRC-E) to guide the choice of empirical therapy. Other new topics included empirical antibacterial therapy in patients with a reported penicillin allergy and the role of pharmacokinetics and pharmacodynamics to guide dosing in sepsis. We also established recommendations on timing and duration of antibacterial treatment. CONCLUSIONS: Our multidisciplinary committee formulated evidence-based recommendations for the empiric antibacterial therapy of adults with sepsis in The Netherlands.

[Current inpatient treatment options for COVID-19: an update]. / Medicamenteuze behandeling covid-19 in de tweede lijn.

In this article we provide an overview of the current treatment recommendations for COVID-19. These recommendations are made by the SWAB (StichtingWerkgroepAntibioticabeleid), in cooperation with the FMS (FederatieMedischSpecialisten (online: swab.nl/nl/covid-19.). Treatment options for patients in both ambulatory care and admitted to the hospital are listed. These treatment options include both antiinflammatory and antiviral therapy.

Total bodyweight and sex both drive pharmacokinetic variability of fluconazole in obese adults.

BACKGROUND: Fluconazole is commonly used to treat or prevent fungal infections. It is typically used orally but in critical situations, IV administration is needed. Obesity may influence the pharmacokinetics and therapeutic efficacy of a drug. In this study, we aim to assess the impact of obesity on fluconazole pharmacokinetics given orally or IV to guide dose adjustments for the obese population. METHODS: We performed a prospective pharmacokinetic study with intensive sampling in obese subjects undergoing bariatric surgery (n = 17, BMI ≥ 35 kg/m2) and non-obese healthy controls (n = 8, 18.5 ≤ BMI < 30.0 kg/m2). Participants received a semi-simultaneous oral dose of 400 mg fluconazole capsules, followed after 2 h by 400 mg IV. Population pharmacokinetic modelling and simulation were performed using NONMEM 7.3. RESULTS: A total of 421 fluconazole concentrations in 25 participants (total bodyweight 61.0-174 kg) until 48 h after dosing were obtained. An estimated bioavailability of 87.5% was found for both obese and non-obese subjects, with a 95% distribution interval of 43.9%-98.4%. With increasing total bodyweight, both higher CL and Vd were found. Sex also significantly impacted Vd, being 27% larger in male compared with female participants. CONCLUSIONS: In our population of obese but otherwise healthy individuals, obesity clearly alters the pharmacokinetics of fluconazole, which puts severely obese adults, particularly if male, at risk of suboptimal exposure, for which adjusted doses are proposed.

Ciprofloxacin Pharmacokinetics After Oral and Intravenous Administration in (Morbidly) Obese and Non-obese Individuals: A Prospective Clinical Study.

BACKGROUND AND OBJECTIVE: Ciprofloxacin is a fluoroquinolone used for empirical and targeted therapy of a wide range of infections. Despite the increase in obesity prevalence, only very limited guidance is available on whether the ciprofloxacin dose needs to be adjusted when administered orally or intravenously in (morbidly) obese individuals. Our aim was to evaluate the influence of (morbid) obesity on ciprofloxacin pharmacokinetics after both oral and intravenous administration, to ultimately guide dosing in this population. METHODS: (Morbidly) obese individuals undergoing bariatric surgery received ciprofloxacin either orally (500 mg; n = 10) or intravenously (400 mg; n = 10), while non-obese participants received semi-simultaneous oral dosing of 500 mg followed by intravenous dosing of 400 mg 3 h later (n = 8). All participants underwent rich sampling (11-17 samples) for 12 h after administration. Non-linear mixed-effects modelling and simulations were performed to evaluate ciprofloxacin exposure in plasma. Prior data from the literature were subsequently included in the model to explore exposure in soft tissue in obese and non-obese patients. RESULTS: Overall, 28 participants with body weights ranging from 57 to 212 kg were recruited. No significant influence of body weight on bioavailability, clearance or volume of distribution was identified (all p > 0.01). Soft tissue concentrations were predicted to be lower in obese individuals despite similar plasma concentrations compared with non-obese individuals. CONCLUSION: Based on plasma pharmacokinetics, we found no evidence of the influence of obesity on ciprofloxacin pharmacokinetic parameters; therefore, ciprofloxacin dosages do not need to be increased routinely in obese individuals. In the treatment of infections in tissue where impaired ciprofloxacin penetration is anticipated, higher dosages may be required. TRIAL REGISTRATION: Registered in the Dutch Trial Registry (NTR6058).

The dynamics in applied COVID-19 pharmacotherapy and the influence of national guidance in The Netherlands: a quantitative and qualitative study.

OBJECTIVE: At the beginning of the COVID-19 pandemic in the Netherlands, the Dutch Working Party on Antibiotic Policy constructed an advisory document about off-label drug treatment options that was regularly updated with new scientific findings. The aim of this study is to describe the dynamics in applied COVID-19 pharmacotherapy during the first 100 days of the pandemic and to assess how the national advisory document influenced local hospital policies. METHODS: A multicentre observational cohort study was conducted in six hospitals in the Netherlands. Patients with confirmed COVID-19 admitted between 27 February and 7 June 2020 were studied. Drug prescription data were collected and percentages of patients receiving a specific treatment were calculated. These percentages were plotted together with release dates of the national advisory document. Semi-structured in-depth interviews with hospital pharmacists and infectious diseases specialists were conducted to gain insight into the development and implementation of pharmacotherapy treatment protocols in hospitals. RESULTS: Data from 1511 patients (60% men, mean age 66 years) were analysed. From mid-March (hydroxy)chloroquine was being prescribed in all six hospitals to approximately 70% of patients at admission. Frequencies of other off-label treatments were below 2%. In the week of 6 April 2020, the first hospital discontinued prescribing (hydroxy)chloroquine and the last hospital discontinued in the week of 4 May 2020 (total range -19 to +10 days after the national advisory document advised against its use (1 May 2020)). All interviewees (n=6) stated that the hospitals based their policies mainly on the national advisory document but also assessed scientific literature themselves. Order panels were constructed to support prescribing. CONCLUSION: Dutch hospitals opted en masse for (hydroxy)chloroquine as COVID-19 therapy at the start of the pandemic, although the time until the therapy was no longer prescribed differed by several weeks. The fact that hospitals defined pharmacotherapy regimens based on their own assessment of the scientific literature besides the national advisory document can explain this variation.

Narrow-spectrum antibiotics for community-acquired pneumonia in Dutch adults (CAP-PACT): a cross-sectional, stepped-wedge, cluster-randomised, non-inferiority, antimicrobial stewardship intervention trial.

BACKGROUND: Adults hospitalised to a non-intensive care unit (ICU) ward with moderately severe community-acquired pneumonia are frequently treated with broad-spectrum antibiotics, despite Dutch guidelines recommending narrow-spectrum antibiotics. Therefore, we investigated whether an antibiotic stewardship intervention would reduce the use of broad-spectrum antibiotics in patients with moderately severe community-acquired pneumonia without compromising their safety. METHODS: In this cross-sectional, stepped-wedge, cluster-randomised, non-inferiority trial (CAP-PACT) done in 12 hospitals in the Netherlands, we enrolled immunocompetent adults (≥18 years) who were admitted to a non-ICU ward and had a working diagnosis of moderately severe community-acquired pneumonia. All participating hospitals started in a control period and every 3 months a block of two hospitals transitioned from the control to the intervention period, with all hospitals eventually ending in the intervention period. The unit of randomisation was the hospital (cluster), and electronic randomisation (by an independent data manager) decided the sequence (the time of intervention) by which hospitals would cross over from the control period to the intervention period. Blinding was not possible. The antimicrobial stewardship intervention was a bundle targeting health-care providers and comprised education, engaging opinion leaders, and prospective audit and feedback of antibiotic use. The co-primary outcomes were broad-spectrum days of therapy per patient, tested by superiority, and 90-day all-cause mortality, tested by non-inferiority with a non-inferiority margin of 3%, and were analysed in the intention-to-treat population, comprising all patients who were enrolled in the control and intervention periods. This trial was prospectively registered at ClinicalTrials.gov, NCT02604628. FINDINGS: Between Nov 1, 2015, and Nov 1, 2017, 5683 patients were assessed for eligibility, of whom 4084 (2235 in the control period and 1849 in the intervention period) were included in the intention-to-treat analysis. The adjusted mean broad-spectrum days of therapy per patient were reduced from 6·5 days in the control period to 4·8 days in the intervention period, yielding an absolute reduction of -1·7 days (95% CI -2·4 to -1·1) and a relative reduction of 26·6% (95% CI 18·0-35·3). Crude 90-day mortality was 10·9% (242 of 2228 died) in the control period and 10·8% (199 of 1841) in the intervention period, yielding an adjusted absolute risk difference of 0·4% (90% CI -2·7 to 2·4), indicating non-inferiority. INTERPRETATION: In patients hospitalised with moderately severe community-acquired pneumonia, a multifaceted antibiotic stewardship intervention might safely reduce broad-spectrum antibiotic use. FUNDING: None.

Discontinuation of Antihypertensive Medications on the Outcome of Hospitalized Patients With Severe Acute Respiratory Syndrome-Coronavirus 2.

[Figure: see text].

Women are started on a lower daily dose of metoprolol than men irrespective of dose recommendations: A potential source of confounding by contraindication in pharmacoepidemiology.

PURPOSE: Current guidelines have no sex-specific dosage advice for metoprolol. To evaluate whether women and men are prescribed the same dose a cohort analysis was performed in the population-based Rotterdam Study (RS). Results were replicated in the Integrated Primary Care Information (IPCI) database of automated general practice data. METHODS: The mean daily starting doses of metoprolol in both sexes were compared with independent-samples t-tests and a linear regression analysis was used to adjust in the RS for co-variables, notably, cardiovascular comorbidity, migraine, age, SBP, DBP, BMI, socioeconomic status, use of other antihypertensive drugs, smoking, and alcohol. In the IPCI-database, adjustment was for age only. RESULTS: The mean daily starting dose was statistically significantly lower in women than in men in both the RS and IPCI database, with a mean difference of 4.8 mg (95%CI -7.8, -1.8) and 4.6 mg (95%CI -5.3,-4.0), respectively. Statistical significance remained after adjustment in both databases. CONCLUSIONS: Women received lower starting doses of metoprolol than men in two independent data collections despite non-sex specific cardiovascular guideline recommendations. This example of real-life pharmacotherapy can lead to a form of confounding by contraindication in pharmacoepidemiology.

[The medicinal treatment of COVID-19: a brief update]. / Medicamenteuze behandeling van COVID-19.

Much has changed in the medical treatment of COVID-19 after the first patient with an infection with SARS-CoV-2 in the Netherlands was diagnosed in February 2020. On the basis of limited data, at first only off-label use of (hydroxy)chloroquine seemed to be a treatment option. However, now based on the findings of several randomized studies, other medicines have been included in the Dutch guidelines about the treatment of COVID-19. In this article, we will briefly discuss the current state of affairs with regard to the drugs (hydroxy) chloroquine, remdesivir and corticosteroids. Again, it appears that only well-executed randomized clinical trials can determine the status of various supposedly effective drugs.

The burden of bacteremic and non-bacteremic Gram-negative infections: A prospective multicenter cohort study in a low-resistance country.

Objectives There is a global increase in infections caused by Gram-negative bacteria. The majority of research is on bacteremic Gram-negative infections (GNI), leaving a knowledge gap on the burden of non-bacteremic GNI. Our aim is to describe characteristics and determine the burden of bacteremic and non-bacteremic GNI in hospitalized patients in the Netherlands. Methods We conducted a prospective cohort study of patients in eight hospitals with microbiologically confirmed GNI, between June 2013 and November 2015. In each hospital the first five adults meeting the eligibility criteria per week were enrolled. We estimated the national incidence and mortality of GNI by combining the cohort data with a national surveillance database for antimicrobial resistance. Results 1,954 patients with GNI were included of which 758 (39%) were bloodstream infections (BSI). 243 GNI (12%) involved multi-drug resistant pathogens. 30-day mortality rate was 11.1% (n = 217) Estimated national incidences of non-bacteremic GNI and bacteremic GNI in hospitalized adults were 74 (95% CI 58 - 89) and 86 (95% CI 72-100) per 100,000 person years, yielding estimated annual numbers of 30-day all-cause mortality deaths of 1,528 (95% CI 1,102-1,954) for bacteremic and 982 (95% CI 688 - 1,276) for non-bacteremic GNI. Conclusion GNI form a large mortality burden in a low-resistance country. A third of the associated mortality occurs after non-bacteremic GNI.

Attributable mortality of antibiotic resistance in gram-negative infections in the Netherlands: a parallel matched cohort study.

OBJECTIVES: Antibiotic resistance in Gram-negative bacteria has been associated with increased mortality. This was demonstrated mostly for third-generation cephalosporin-resistant (3GC-R) Enterobacterales bacteraemia in international studies. Yet, the burden of resistance specifically in the Netherlands and created by all types of Gram-negative infection has not been quantified. We therefore investigated the attributable mortality of antibiotic resistance in Gram-negative infections in the Netherlands. METHODS: In eight hospitals, a sample of Gram-negative infections was identified between 2013 and 2016, and separated into resistant and susceptible infection cohorts. Both cohorts were matched 1:1 to non-infected control patients on hospital, length of stay at infection onset, and age. In this parallel matched cohort set-up, 30-day mortality was compared between infected and non-infected patients. The impact of resistance was then assessed by dividing the two separate risk ratios (RRs) for mortality attributable to Gram-negative infection. RESULTS: We identified 1954 Gram-negative infections, of which 1190 (61%) involved Escherichia coli, 210 (11%) Pseudomonas aeruginosa, and 758 (39%) bacteraemia. Resistant Gram-negatives caused 243 infections (12%; 189 (78%) 3GC-R Enterobacterales, nine (4%) multidrug-resistant P. aeruginosa, no carbapenemase-producing Enterobacterales). Subsequently, we matched 1941 non-infected controls. After adjustment, point estimates for RRs comparing mortality between infections and controls were similarly higher than 1 in case of resistant infections and susceptible infections (1.42 (95% confidence interval 0.66-3.09) and 1.32 (1.06-1.65), respectively). By dividing these, the RR reflecting attributable mortality of resistance was calculated as 1.08 (0.48-2.41). CONCLUSIONS: In the Netherlands, antibiotic resistance did not increase 30-day mortality in Gram-negative infections.

Impact of antimicrobial de-escalation on mortality: a literature review of study methodology and recommendations for observational studies.

Introduction: The safety of de-escalation of empirical antimicrobial therapy is largely based on observational data, with many reporting protective effects on mortality. As there is no plausible biological explanation for this phenomenon, it is most probably caused by confounding by indication.Areas covered: We evaluate the methodology used in observational studies on the effects of de-escalation of antimicrobial therapy on mortality. We extended the search for a recent systematic review and identified 52 observational studies. The heterogeneity in study populations was large. Only 19 (36.5%) studies adjusted for confounders and four (8%) adjusted for clinical stability during admission, all as a fixed variable. All studies had methodological limitations, most importantly the lack of adjustment for clinical stability, causing bias toward a protective effect.Expert opinion: The methodology used in studies evaluating the effects of de-escalation on mortality requires improvement. We depicted all potential confounders in a directed acyclic graph to illustrate all associations between exposure (de-escalation) and outcome (mortality). Clinical stability is an important confounder in this association and should be modeled as a time-varying variable. We recommend to include de-escalation as time-varying exposure and use inverse-probability-of-treatment weighted marginal structural models to properly adjust for time-varying confounders.