Exact joint density-current probability function for the asymmetric exclusion process

We study the asymmetric exclusion process with open boundaries and derive the exact form of the joint probability function for the occupation number and the current through the system. We further consider the thermodynamic limit, showing that the resulting distribution is non-Gaussian and that the density fluctuations have a discontinuity at the continuous phase transition, while the current fluctuations are continuous. The derivations are performed by using the standard operator algebraic approach, and by the introduction of new operators satisfying a modified version of the original algebra.Comment: 4 pages, 3 figure

Exact probability function for bulk density and current in the asymmetric exclusion process

We examine the asymmetric simple exclusion process with open boundaries, a paradigm of driven diffusive systems, having a nonequilibrium steady state transition. We provide a full derivation and expanded discussion and digression on results previously reported briefly in M. Depken and R. Stinchcombe, Phys. Rev. Lett. {\bf 93}, 040602, (2004). In particular we derive an exact form for the joint probability function for the bulk density and current, both for finite systems, and also in the thermodynamic limit. The resulting distribution is non-Gaussian, and while the fluctuations in the current are continuous at the continuous phase transitions, the density fluctuations are discontinuous. The derivations are done by using the standard operator algebraic techniques, and by introducing a modified version of the original operator algebra. As a byproduct of these considerations we also arrive at a novel and very simple way of calculating the normalization constant appearing in the standard treatment with the operator algebra. Like the partition function in equilibrium systems, this normalization constant is shown to completely characterize the fluctuations, albeit in a very different manner.Comment: 10 pages, 4 figure

Scepticaemia: The impact on the health system and patients of delaying new treatments with uncertain evidence; a case study of the sepsis bundle [version 2; referees: 2 approved]

Background: A sepsis care bundle of intravenous vitamin C, thiamine, and hydrocortisone was reported to improve treatment outcomes. The data to support it are uncertain and decision makers are likely to be cautious about adopting it. The objective of this study was to model the opportunity costs in dollars and lives of waiting for better information before adopting the bundle. Methods: A decision tree was built using information from the literature. We modelled the impact of bundle adoption under three scenarios using a simulation in which the bundle was effective as reported in the primary trial, less effective based on other information, and ineffective. The measurements were health services costs, quality-adjusted life years, and transition probabilities. Results: If the bundle proves to be effective under either scenario, it will save billions of dollars and millions of life-years in the United States. This is the opportunity cost of delaying an adoption decision and waiting for better quality evidence. We suggest that hospital decision-makers consider implementing the bundle on a trial basis while monitoring costs and outcomes data even while the evidence base is uncertain. Conclusions: If the decision maker is unwilling to use the best available evidence now, but rather wishes to wait for definitive evidence they are risking incurring large costs for health care systems and for the patients they serve. An explicit analysis of uncertain clinical outcomes is a useful adjunct to guide decision making where there is clinical ambiguity. This approach offers a valid alternative to the default of clinical inactivity when faced with uncertainty

Patient and economic impact of implementing a paediatric sepsis pathway in emergency departments in Queensland, Australia.

We examined systems-level costs before and after the implementation of an emergency department paediatric sepsis screening, recognition and treatment pathway. Aggregated hospital admissions for all children aged < 18y with a diagnosis code of sepsis upon admission in Queensland, Australia were compared for 16 participating and 32 non-participating hospitals before and after pathway implementation. Monte Carlo simulation was used to generate uncertainty intervals. Policy impacts were estimated using difference-in-difference analysis comparing observed and expected results. We compared 1055 patient episodes before (77.6% in-pathway) and 1504 after (80.5% in-pathway) implementation. Reductions were likely for non-intensive length of stay (- 20.8 h [- 36.1, - 8.0]) but not intensive care (-9.4 h [- 24.4, 5.0]). Non-pathway utilisation was likely unchanged for interhospital transfers (+ 3.2% [- 5.0%, 11.4%]), non-intensive (- 4.5 h [- 19.0, 9.8]) and intensive (+ 7.7 h, [- 20.9, 37.7]) care length of stay. After difference-in-difference adjustment, estimated savings were 596 [277, 942] non-intensive and 172 [148, 222] intensive care days. The program was cost-saving in 63.4% of simulations, with a mean value of $97,019 [-$857,273, $1,654,925] over 24 months. A paediatric sepsis pathway in Queensland emergency departments was associated with potential reductions in hospital utilisation and costs

Convalescent plasma in patients admitted to hospital with COVID-19 (RECOVERY): a randomised controlled, open-label, platform trial

SummaryBackground Azithromycin has been proposed as a treatment for COVID-19 on the basis of its immunomodulatoryactions. We aimed to evaluate the safety and efficacy of azithromycin in patients admitted to hospital with COVID-19.Methods In this randomised, controlled, open-label, adaptive platform trial (Randomised Evaluation of COVID-19Therapy [RECOVERY]), several possible treatments were compared with usual care in patients admitted to hospitalwith COVID-19 in the UK. The trial is underway at 176 hospitals in the UK. Eligible and consenting patients wererandomly allocated to either usual standard of care alone or usual standard of care plus azithromycin 500 mg once perday by mouth or intravenously for 10 days or until discharge (or allocation to one of the other RECOVERY treatmentgroups). Patients were assigned via web-based simple (unstratified) randomisation with allocation concealment andwere twice as likely to be randomly assigned to usual care than to any of the active treatment groups. Participants andlocal study staff were not masked to the allocated treatment, but all others involved in the trial were masked to theoutcome data during the trial. The primary outcome was 28-day all-cause mortality, assessed in the intention-to-treatpopulation. The trial is registered with ISRCTN, 50189673, and ClinicalTrials.gov, NCT04381936.Findings Between April 7 and Nov 27, 2020, of 16 442 patients enrolled in the RECOVERY trial, 9433 (57%) wereeligible and 7763 were included in the assessment of azithromycin. The mean age of these study participants was65·3 years (SD 15·7) and approximately a third were women (2944 [38%] of 7763). 2582 patients were randomlyallocated to receive azithromycin and 5181 patients were randomly allocated to usual care alone. Overall,561 (22%) patients allocated to azithromycin and 1162 (22%) patients allocated to usual care died within 28 days(rate ratio 0·97, 95% CI 0·87–1·07; p=0·50). No significant difference was seen in duration of hospital stay (median10 days [IQR 5 to >28] vs 11 days [5 to >28]) or the proportion of patients discharged from hospital alive within 28 days(rate ratio 1·04, 95% CI 0·98–1·10; p=0·19). Among those not on invasive mechanical ventilation at baseline, nosignificant difference was seen in the proportion meeting the composite endpoint of invasive mechanical ventilationor death (risk ratio 0·95, 95% CI 0·87–1·03; p=0·24).Interpretation In patients admitted to hospital with COVID-19, azithromycin did not improve survival or otherprespecified clinical outcomes. Azithromycin use in patients admitted to hospital with COVID-19 should be restrictedto patients in whom there is a clear antimicrobial indication

Floresco Toowoomba: Final Evaluation Report

The Innovation: The Floresco project is a community-based integrated service model that provides a holistic, person-centred, ‘one-stop shop’ for clinical care and psychosocial support in the Darling Downs Hospital and Health Service region. The Floresco Centre involves a consortium of co-located health providers and social service agencies delivering a range of community-based psychosocial support services including one-to-one care, group sessions, peer support, self-help, and family and carer support. It uses a centralised and streamlined process for the referral, intake, triage, assessment and treatment of adults experiencing mental illness.Key Evaluation Findings: The Floresco project increased the accessibility of integrated mental health care in the DDHHS region. The new model of care was successfully implemented, well accepted by partner organisations and front-line staff, and received overwhelmingly positive feedback from service users. Evidence also suggests that the project may have decreased mental health emergency department presentations and mental health admissions at Toowoomba Hospital. However, direct attribution is difficult due to limitations in the robustness of the data, and a number of additional hospital avoidance strategies in place within DDHHS. Significant improvements were also seen in mental health outcomes and quality of life within a representative sample of Floresco service user

HealthPathways: An economic analysis of the impact of primary care pathways in Mackay, Queensland

HealthPathways overview:HealthPathways is a clinical pathway portal that enables general practitioners (GPs) to better manage their patients in the primary sector. Pathways for various diseases assist GPs with patient assessment, management, referrals, and best practices tailored to the local context to provide more comprehensive care. AusHSI was contracted to conduct an economic analysis of HealthPathways for four disease groups: cardiology, diabetes, urology, and respiratory conditions. In this paper we sought to analyse the impact of Mackay HealthPathways on patients, providers, and the health system through economic analysis. HealthPathways is designed to improve referral appropriateness, improve GP confidence in managing complex conditions, and reduce unnecessary care. The program is intended to ensure the right care, at the right time, in the right place and delivered to the right person.Analysis and results:The data included in the analysis were aggregate PenCAT figures across Mackay region, primary care referrals, and all acute and specialist outpatient utilisation from January to March in 2015 and 2017. Diabetes was chosen as the intervention group as it featured comprehensive HealthPathways implementation. Urology was not supported by HealthPathways as of March 2017 and represents the control group. Cardiology and respiratory conditions represent partially implemented HealthPathways conditions. While statistically rigorous conclusions were not possible, we showed that the diabetes pathways improved referral appropriateness by 27%, while the urology control group experienced a 15% rise in inappropriate referrals. There was no decline in health outcomes and no increase in hospital costs from avoiding these referrals.Implications for Mackay and Queensland:While more research is required to show cost-effectiveness and outcomes for patient health, the Mackay Health system could potentially save hundreds of thousands of dollars in avoided unnecessary referrals per Pathway. If HealthPathways is fully integrated across Queensland for every chronic disease requiring referrals, the program could generate even greater cost savings. We believe there is sufficient evidence to continue the HealthPathways program while collecting comprehensive data to determine the health and economic impacts.Recommendations:AusHSI recommends the continuation of HealthPathways provided that the program is fully implemented as per the diabetes clinical pathway. This includes a developed suite of clinical and referral pathways, however the diabetes pathway’s success was likely due in part to the requirement for GPs to consult HealthPathways before making referrals. This is a critical component that should be expanded to other available pathways. AusHSI also recommends that a comprehensive HealthPathways evaluation be conducted using patient-level data to identify whether HealthPathways can be a cost-effective program across the state of Queensland

Resource use and costs associated with epilepsy in the Queensland hospital system: Protocol for a population-based data linkage study

Introduction: Epilepsy places a large burden on health systems, with hospitalisations for seizures alone occurring more frequently than those related to diabetes. However, the cost of epilepsy to the Australian health system is not well understood. The primary aim of this study is to quantify the health service use and cost of epilepsy in Queensland, Australia. Secondary aims are to identify differences in health service use and cost across population and disease subgroups, and to explore the associations between health service use and common comorbidities. Methods and analysis: This project will use data linkage to identify the health service utilisation and costs associated with epilepsy. A base cohort of patients will be identified from the Queensland Hospital Admitted Patient Data Collection. We will select all patients admitted between 2014 and 2018 with a diagnosis classification related to epilepsy. Two comparison cohorts will also be identified. Retrospective hospital admissions data will be linked with emergency department presentations, clinical costing data, specialist outpatient and allied health occasions of service data and mortality data. The level of health service use in Queensland, and costs associated with this, will be quantified using descriptive statistics. Difference in health service costs between groups will be explored using logistic regression. Linear regression will be used to model the associations of interest. The analysis will adjust for confounders including age, sex, comorbidities, indigenous status, and remoteness. Ethics and dissemination: Ethical approval has been obtained through the QUT University Human Research Ethics Committee (1900000333). Permission to waive consent has been granted under the Public Health Act 2005, with approval provided by all relevant data custodians. Findings of the proposed research will be communicated through presentations at national and international conferences, presentations to key stakeholders and decision-makers, and publications in international peer-reviewed journals.</p

Adherence to best practice: Preventing surgical site infection following caesarean section in Australia

Background: Surgical site infection (SSI) following caesarean section is a serious but underreported problem with an estimated incidence of 5–9%. It is essential to identify adherence to established prevention strategies to reduce the incidence rate. Aims: The aims of this study were to quantify unwarranted variation from evidence-based practice on the prevention of SSI at caesarean section in Australia; and to identify predictors of not implementing an existing infection prevention bundle: pre-incision antibiotic prophylaxis, vaginal preparation and spontaneous placenta removal. Materials and methods: An online cross-sectional survey of obstetricians and obstetric Diplomates was conducted in 2016. The primary outcome was adherence to an existing infection prevention bundle, with demographic and clinical variables predicting adherence through multivariable binary logistic regression. Results: Forty-nine percent of respondents (response rate 39.6%) reported implementing zero or only one element of the infection prevention bundle. The types of respondents most likely to have poor adherence were Diplomates (adjusted odds ratio (aOR) 2.58), obstetricians practising in private hospitals (aOR 3.34), those usually practising in public and private hospitals (aOR 2.23), and those not usually implementing a surgical safety checklist (aOR 3.77). Conclusions: Adherence to best practice at caesarean section is low among many Australian obstetricians. Infection control practitioners and obstetricians need to collaboratively implement surgical safety checklists at caesarean section, and monitor implementation using process key performance indicators, and audit and feedback. These strategies will reduce unwarranted variation from evidence-based infection control practice.</p