Bayesian Credible Interval Research Articles

Mixture of transmuted Pareto distribution: Properties, applications and estimation under Bayesian framework

Transmuted distributions are flexible skewed families constructed by the induction of one or more additional parameters to a parent distribution. This paper investigates the potential usefulness of a two-component mixture of Transmuted Pareto Distribution (TPaD) under a Bayesian framework assuming type-I right censored sampling. For Bayesian analysis, noninformative as well as informative priors are assumed while three loss functions, namely the squared error loss function (SELF), precautionary loss function (PLF), and quadratic loss function (QLF) are considered to estimate the unknown parameters. Furthermore, Bayesian credible intervals (BCIs) are also discussed in this study. Since the posterior distributions do not have explicit forms, posterior summaries are computed using a Markov Chain Monte Carlo (MCMC) technique. The performance of the Bayes estimators is assessed by their posterior risks assuming different sample sizes and censoring rates. To highlight the practical significance of a two-component mixture of transmuted Pareto distribution (TPaD), a medical data set collected for rental calculi problem is analyzed in this study. Furthermore, annual flood rate data collected at the Floyd River are also discussed in this study.

Bayes Factor Meta-Analysis of the Mortality Claim for Peripheral Paclitaxel-Eluting Devices

ObjectivesThe aim of the present study was to quantify the probability of increased mortality with paclitaxel compared with control in a dataset of 28 randomized controlled trials. BackgroundAnalysis of data from 28 randomized controlled trials using conventional null-hypothesis statistical testing has produced the unexpected finding of a 68% increase in mortality at 2 years and a 93% increase at 3 to 5 years after using paclitaxel-eluting balloons and stents to treat femoropopliteal arterial disease, but no biologic explanation for increased mortality has been identified. MethodsA Bayesian sequential model was developed to quantify the probability of increased mortality 1, 2, and 3 to 5 years after treatment, and p values were replaced with meta-analytic Bayes factors (BFs), which provide decisive evidence at values >100 and very strong evidence at values of 32 to 100. ResultsThe evidence for increased mortality at 1 year (BF = 0.02), 2 years (BF = 8.5), and 3 to 5 years (BF = 14.6) was less than conclusive. All-cause mortality at 1 year was similar between the paclitaxel and control arms at 1 year (odds ratio: 0.92; 95% Bayesian credible interval: 0.53 to 1.53) and 2 years (odds ratio: 1.23; 95% Bayesian credible interval: 0.84 to 1.71) but was increased at 3 to 5 years (odds ratio: 1.43; 95% Bayesian credible interval: 1.01 to 1.90). ConclusionsThis study finds some support for increased mortality after using paclitaxel-eluting devices in femoropopliteal arterial disease, but the evidence is not unequivocal and may not sway skeptical investigators concerned about causation, unreported studies, or the post hoc analysis of trials underpowered for mortality.

Local and regional flood frequency analysis based on hierarchical Bayesian model in Dongting Lake Basin, China

This study developed a hierarchical Bayesian (HB) model for local and regional flood frequency analysis in the Dongting Lake Basin, in China. The annual maximum daily flows from 15 streamflow-gauged sites in the study area were analyzed with the HB model. The generalized extreme value (GEV) distribution was selected as the extreme flood distribution, and the GEV distribution location and scale parameters were spatially modeled through a regression approach with the drainage area as a covariate. The Markov chain Monte Carlo (MCMC) method with Gibbs sampling was employed to calculate the posterior distribution in the HB model. The results showed that the proposed HB model provided satisfactory Bayesian credible intervals for flood quantiles, while the traditional delta method could not provide reliable uncertainty estimations for large flood quantiles, due to the fact that the lower confidence bounds tended to decrease as the return periods increased. Furthermore, the HB model for regional analysis allowed for a reduction in the value of some restrictive assumptions in the traditional index flood method, such as the homogeneity region assumption and the scale invariance assumption. The HB model can also provide an uncertainty band of flood quantile prediction at a poorly gauged or ungauged site, but the index flood method with L-moments does not demonstrate this uncertainty directly. Therefore, the HB model is an effective method of implementing the flexible local and regional frequency analysis scheme, and of quantifying the associated predictive uncertainty.

Finite tidal effects in GW170817: Observational evidence or model assumptions?

After the detection of gravitational waves caused by the coalescence of compact objects in the mass range of neutron stars, GW170817, several studies have searched for an imprint of tidal effects in the signal, employing different model assumptions. One important distinction is whether or not to assume that both objects are neutron stars and obey the same equation of state. Some studies assumed independent properties. Others assume a universal equation of state, and in addition that the tidal deformability follows certain phenomenological relations. An important question is whether the gravitational-wave data alone constitute observational evidence for finite tidal effects. All studies provide Bayesian credible intervals, often without sufficiently discussing the impact of prior assumptions, especially in the case of lower limits on the neutron-star tidal deformability or radius. In this article, we scrutinize the implicit and explicit prior assumptions made in those studies. Our findings strongly indicate that existing lower credible bounds are mainly a consequence of prior assumptions combined with information gained about the system's masses. Importantly, those lower bounds are typically not informed by the observation of tidal effects in the gravitational-wave signal. Thus, regarding them as observational evidence might be misleading without a more detailed discussion. Further, we point out technical problems and conceptual inconsistencies in existing studies. We also assess the limitations due to systematic waveform model uncertainties in a novel way, demonstrating that differences between existing models are not guaranteed to be small enough for an unbiased estimation of lower bounds on the tidal deformability. Finally, we propose strategies for gravitational-wave data analysis designed to avoid some of the problems we uncovered.

Bedaquiline, moxifloxacin, pretomanid, and pyrazinamide during the first 8 weeks of treatment of patients with drug-susceptible or drug-resistant pulmonary tuberculosis: a multicentre, open-label, partially randomised, phase 2b trial

SummaryBackgroundNew anti-tuberculosis regimens that are shorter, simpler, and less toxic than those that are currently available are needed as part of the global effort to address the tuberculosis epidemic. We aimed to investigate the bactericidal activity and safety profile of combinations of bedaquiline, pretomanid, moxifloxacin, and pyrazinamide in the first 8 weeks of treatment of pulmonary tuberculosis.MethodsIn this multicentre, open-label, partially randomised, phase 2b trial, we prospectively recruited patients with drug-susceptible or rifampicin-resistant pulmonary tuberculosis from seven sites in South Africa, two in Tanzania, and one in Uganda. Patients aged 18 years or older with sputum smear grade 1+ or higher were eligible for enrolment, and a molecular assay (GeneXpert or MTBDRplus) was used to confirm the diagnosis of tuberculosis and to distinguish between drug-susceptible and rifampicin-resistant tuberculosis. Patients who were HIV positive with a baseline CD4 cell count of less than 100 cells per uL were excluded. Patients with drug-susceptible tuberculosis were randomly assigned (1:1:1) using numbered treatment packs with sequential allocation by the pharmacist to receive 56 days of treatment with standard tuberculosis therapy (oral isoniazid, rifampicin, pyrazinamide, and ethambutol; HRZE), or pretomanid (oral 200 mg daily) and pyrazinamide (oral 1500 mg daily) with either oral bedaquiline 400 mg daily on days 1–14 then 200 mg three times per week (BloadPaZ) or oral bedaquiline 200 mg daily (B200PaZ). Patients with rifampicin-resistant tuberculosis received 56 days of the B200PaZ regimen plus moxifloxacin 400 mg daily (BPaMZ). All treatment groups were open label, and randomisation was not stratified. Patients, trial investigators and staff, pharmacists or dispensers, laboratory staff (with the exception of the mycobacteriology laboratory staff), sponsor staff, and applicable contract research organisations were not masked. The primary efficacy outcome was daily percentage change in time to sputum culture positivity (TTP) in liquid medium over days 0–56 in the drug-susceptible tuberculosis population, based on non-linear mixed-effects regression modelling of log10 (TTP) over time. The efficacy analysis population contained patients who received at least one dose of medication and who had efficacy data available and had no major protocol violations. The safety population contained patients who received at least one dose of medication. This study is registered with ClinicalTrials.gov, NCT02193776, and all patients have completed follow-up.FindingsBetween Oct 24, 2014, and Dec 15, 2015, we enrolled 180 patients with drug-susceptible tuberculosis (59 were randomly assigned to BloadPaZ, 60 to B200PaZ, and 61 to HRZE) and 60 patients with rifampicin-resistant tuberculosis. 57 patients in the BloadPaZ group, 56 in the B200PaZ group, and 59 in the HRZE group were included in the primary analysis. B200PaZ produced the highest daily percentage change in TTP (5·17% [95% Bayesian credibility interval 4·61–5·77]), followed by BloadPaZ (4·87% [4·31–5·47]) and HRZE group (4·04% [3·67–4·42]). The bactericidal activity in B200PaZ and BloadPaZ groups versus that in the HRZE group was significantly different. Higher proportions of patients in the BloadPaZ (six [10%] of 59) and B200PaZ (five [8%] of 60) groups discontinued the study drug than in the HRZE group (two [3%] of 61) because of adverse events. Liver enzyme elevations were the most common grade 3 or 4 adverse events and resulted in the withdrawal of ten patients (five [8%] in the BloadPaZ group, three [5%] in the B200PaZ group, and two [3%] in the HRZE group). Serious treatment-related adverse events affected two (3%) patients in the BloadPaZ group and one (2%) patient in the HRZE group. Seven (4%) patients with drug-susceptible tuberculosis died and four (7%) patients with rifampicin-resistant tuberculosis died. None of the deaths were considered to be related to treatment.InterpretationB200PaZ is a promising regimen to treat patients with drug-susceptible tuberculosis. The bactericidal activity of both these regimens suggests that they have the potential to shorten treatment, and the simplified dosing schedule of B200PaZ could improve treatment adherence in the field. However, these findings must be investigated further in a phase 3 trial assessing treatment outcomes.FundingTB Alliance, UK Department for International Development, Bill & Melinda Gates Foundation, US Agency for International Development, Directorate General for International Cooperation of the Netherlands, Irish Aid, Australia Department of Foreign Affairs and Trade, and the Federal Ministry for Education and Research of Germany.

ATIM-07. EFFICACY AND SAFETY OF NIVOLUMAB IN PATIENTS WITH FIRST RECURRENCE OF GLIOBLASTOMA: A MULTICENTER, OPEN-LABEL, NON-COMPARATIVE STUDY (ONO-4538-19)

Abstract BACKGROUND The anti-programmed cell death protein 1 (PD-1) immune checkpoint antibody, nivolumab, may be beneficial in patients with recurrent glioblastoma. OBJECTIVE This open-label, non-comparative study assessed the efficacy and safety of nivolumab in Japanese patients with first recurrence of glioblastoma. METHODS Patients with a first recurrence of histologically confirmed World Health Organization (WHO) Grade IV glioma, after treatment with temozolomide plus radiotherapy, received nivolumab 3 mg/kg every 2 weeks until confirmed disease progression based on Response Assessment in Neuro-Oncology (RANO) criteria or development of toxicity. The primary endpoint was 1-year overall survival rate (1y-OS) assessed using a Bayesian approach. The prespecified efficacy criteria were that the Bayesian posterior mean 1y-OS with nivolumab would be 49%, and the Bayesian posterior probability threshold for exceeding the 1y-OS of bevacizumab (34.5%) from the Japanese Phase II study (JO22506) would be 93%. RESULTS Of the 50 patients enrolled, 44 (93.5%) had recurrent malignant glioma (glioblastoma and gliosarcoma), 26 (59.1%) had measurable disease, and 4 (9.1%) received corticosteroids at baseline. The posterior mean (90% Bayesian credible intervals) 1y-OS with nivolumab was 54.35% (42.27–66.21), and the observed posterior probability of exceeding the 1y-OS of bevacizumab (34.5%, JO22506) was 99.7%. The median (90% confidence interval) overall and progression-free survival (PFS) was 13.09 months (10.38, 17.68) and 1.45 months (1.41, 1.54), respectively. One partial response was observed (objective response rate [ORR] 1/26 evaluable patients [3.8%]). The grade 3–5 treatment-related adverse event rate was 16.0%; most adverse events resolved and were manageable. CONCLUSION The 1y-OS with nivolumab monotherapy in Japanese patients was higher than that in the bevacizumab group in the JO22506 study. However, PFS and ORR were not improved compared with JO22506. The safety profile of nivolumab was consistent with that observed in other tumor types.

The Society of Thoracic Surgeons Composite Score Rating for Pulmonary Resection for Lung Cancer

The Society of Thoracic Surgeons (STS) General Thoracic Surgery Database (GTSD) has developed composite quality measures for lobectomy and esophagectomy. This study sought to develop a composite measure including all resections for lung cancer. The STS lung cancer composite score is based on 2 outcomes: risk-adjusted mortality and morbidity. GTSD data were included from January 2015 to December 2017. "Star ratings" were created for centers with 30 or more cases by using 95% Bayesian credible intervals. The Bayesian model was performed with and without inclusion of the minimally invasive approach to assess the impact of approach on the composite measure. The study population included 38,461 patients from 256 centers. Overall operative mortality was 1.3% (495 of 38,461). The major complication rate was 7.9% (3045 of 38,461). The median number of nodes examined was 10 (interquartile range, 5 to 16); the median number of nodal stations sampled was 4 (interquartile range, 3 to 5). Positive resection margins were identified in 3.7% (1420 of 38,461). A total of 214 centers with 30 or more cases were assigned star ratings. There were 7 1-star, 194 2-star, and 13 3-star programs; 70.6% of resections were performed through a minimally invasive approach. Inclusion of minimally invasive approach, which was adjusted for in previous models, altered the star ratings for 3% (6of 214) of the programs. Participants in the STS GTSD perform lung cancer resection with low morbidity and mortality. Lymph node data suggest that participants are meeting contemporary staging standards. There is wide variability among participants in application of minimally invasive approaches. The study found that risk adjustment for approach altered ratings in 3% of participants.

Evaluating the impact of individual alcohol licensing decisions on local health and crime: a natural experiment with synthetic controls

BackgroundLocal authorities in England can influence the local alcohol environment by contributing to the licensing process and controlling the enforcement of existing licenses. However, a gap remains in the availability of quantitative evidence of effectiveness and impact of these local interventions, including a shortage of public health evidence around individual premises. Natural experiments offer the opportunity to evaluate these interventions where formal randomisation is not possible. We aimed to assess whether it is possible to quantitatively evaluate three natural experiments of alcohol licensing decisions at small spatial scale. MethodsThree situations presenting a natural experiment were identified in different English Local Authority areas by public health or licensing practitioners: (i) the closure of a nightclub in 2013, (ii) the closure of a restaurant-nightclub following reviews in 2016, and (iii) the implementation of new local licensing guidance (LLG) in 2013/14. We obtained monthly numbers of reported incidents of emergency department admissions for alcohol-related reasons, ambulance call-outs, and various crimes at lower/middle-super-output-area level (from 2010–14 for case i, 2015–17 for case ii, and 2008–14 for case iii). Bayesian structural timeseries were used to compare trends to their counterfactuals, approximated by synthetic controls based on time series of the same outcomes in other, comparable, areas. FindingsClosure of the nightclub was associated with temporary reductions in antisocial behaviour (–18%; 95% Bayesian Credible Interval [BCI] –37 to –4); equivalent to 60 averted incidents in 4 months. Closure of the restaurant-nightclub was not associated with measurable changes in outcomes. There was some evidence that the LLG introduction was associated with a reduction in drunk and disorderly behaviour (–42%, 95% BCI –109 to 23), but this reduction equated to less than one incident per month. The unplanned end of the LLG might have contributed to an increase in domestic violence (11%, 95% BCI –10 to 35), corresponding to two additional incidents per month. InterpretationIt is possible to evaluate the impact of local alcohol policies, even at the level of individual premises, using this methodology. We provide quantitative evidence that local government actions to influence the local alcohol environment can have a positive impact on health and crime in the area but could also have unintended consequences. FundingThis work was funded by the National Institute for Health Research School for Public Health Research (NIHR SPHR), a partnership between the Universities of Sheffield, Bristol, Cambridge, Exeter, and University College London); the London School for Hygiene and Tropical Medicine; the LiLaC collaboration between the Universities of Liverpool and Lancaster and Fuse; and the Centre for Translational Research in Public Health, a collaboration between Newcastle, Durham, Northumbria, Sunderland and Teesside Universities. The views expressed are those of the authors and not necessarily those of the National Health Service, the NIHR, or the UK Department of Health.

Geographical variations of the associations between health interventions and all-cause under-five mortality in Uganda

BackgroundTo reduce the under-five mortality (U5M), fine-gained spatial assessment of the effects of health interventions is critical because national averages can obscure important sub-national disparities. In turn, sub-national estimates can guide control programmes for spatial targeting. The purpose of our study is to quantify associations of interventions with U5M rate at national and sub-national scales in Uganda and to identify interventions associated with the largest reductions in U5M rate at the sub-national scale.MethodsSpatially explicit data on U5M, interventions and sociodemographic indicators were obtained from the 2011 Uganda Demographic and Health Survey (DHS). Climatic data were extracted from remote sensing sources. Bayesian geostatistical Weibull proportional hazards models with spatially varying effects at sub-national scales were utilized to quantify associations between all-cause U5M and interventions at national and regional levels. Bayesian variable selection was employed to select the most important determinants of U5M.ResultsAt the national level, interventions associated with the highest reduction in U5M were artemisinin-based combination therapy (hazard rate ratio (HRR) = 0.60; 95% Bayesian credible interval (BCI): 0.11, 0.79), initiation of breastfeeding within 1 h of birth (HR = 0.70; 95% BCI: 0.51, 0.86), intermittent preventive treatment (IPTp) (HRR = 0.74; 95% BCI: 0.67, 0.97) and access to insecticide-treated nets (ITN) (HRR = 0.75; 95% BCI: 0.63, 0.84). In Central 2, Mid-Western and South-West, largest reduction in U5M was associated with access to ITNs. In Mid-North and West-Nile, improved source of drinking water explained most of the U5M reduction. In North-East, improved sanitation facilities were associated with the highest decline in U5M. In Kampala and Mid-Eastern, IPTp had the largest associated with U5M. In Central1 and East-Central, oral rehydration solution and postnatal care were associated with highest decreases in U5M respectively.ConclusionSub-national estimates of the associations between U5M and interventions can guide control programmes for spatial targeting and accelerate progress towards mortality-related Sustainable Development Goals.

Using degradation models to assess pipeline life

AbstractLongitudinal inspections of thickness at particular locations along a pipeline provide useful information to assess the remaining life of the pipeline. In applications with different mechanisms of corrosion processes, we have observed various types of general degradation paths. We present two applications of fitting a degradation model to describe the corrosion initiation and growth behavior in a pipeline. We use a Bayesian approach for parameter estimation for the degradation model. The failure‐time and remaining lifetime distributions are derived from the degradation model, and we compute Bayesian estimates and credible intervals of the failure‐time and remaining lifetime distributions for both individual segments and for the entire pipeline circuit.

Bayesian Empirical Likelihood Inference with Complex Survey Data

SummaryWe propose a Bayesian empirical likelihood approach to survey data analysis on a vector of finite population parameters defined through estimating equations. Our method allows overidentified estimating equation systems and is applicable to both smooth and non-differentiable estimating functions. Our proposed Bayesian estimator is design consistent for general sampling designs and the Bayesian credible intervals are calibrated in the sense of having asymptotically valid design-based frequentist properties under single-stage unequal probability sampling designs with small sampling fractions. Large sample properties of the Bayesian inference proposed are established for both non-informative and informative priors under the design-based framework. We also propose a Bayesian model selection procedure with complex survey data and show that it works for general sampling designs. An efficient Markov chain Monte Carlo procedure is described for the required computation of the posterior distribution for general vector parameters. Simulation studies and an application to a real survey data set are included to examine the finite sample performances of the methods proposed as well as the effect of different types of prior and different types of sampling design.

Calibrated Bayesian credible intervals for binomial proportions

ABSTRACTDrawbacks of traditional approximate and exact confidence intervals for binomial proportions are well recognized. Alternatives include an interval based on inverting the score test, adaptations of exact testing, and Bayesian credible intervals. We propose an approach that calls for selecting an optimal value κ between 0 and 0.5 based on stipulated coverage criteria over a grid of regions comprising the parameter space. One then bases lower and upper limits of a credible interval on Beta(κ, 1−κ) and Beta(1−κ, κ) priors, respectively. The result tends toward a Jeffreys prior-based interval if the goal is to constrain average overall coverage at ≤ 1−α across the full parameter space, and toward the Clopper-Pearson interval if the goal is to constrain region-specific lower and upper lack of coverage rates ≤ α/2 as region widths approach zero. We suggest an intermediate target that demonstrably improves region-specific coverage balance when compared with existing methods.

Mini-FLOTAC as an alternative, non-invasive diagnostic tool for Schistosoma mansoni and other trematode infections in wildlife reservoirs

BackgroundSchistosomiasis and food-borne trematodiases are not only of major public health concern, but can also have profound implications for livestock production and wildlife conservation. The zoonotic, multi-host nature of many digenean trematodes is a significant challenge for disease control programmes in endemic areas. However, our understanding of the epidemiological role that animal reservoirs, particularly wild hosts, may play in the transmission of zoonotic trematodiases suffers a dearth of information, with few, if any, standardised, reliable diagnostic tests available. We combined qualitative and quantitative data derived from post-mortem examinations, coprological analyses using the Mini-FLOTAC technique, and molecular tools to assess parasite community composition and the validity of non-invasive methods to detect trematode infections in 89 wild Hubert’s multimammate mice (Mastomys huberti) from northern Senegal.ResultsParasites isolated at post-mortem examination were identified as Plagiorchis sp., Anchitrema sp., Echinostoma caproni, Schistosoma mansoni, and a hybrid between Schistosoma haematobium and Schistosoma bovis. The reports of E. caproni and Anchitrema sp. represent the first molecularly confirmed identifications for these trematodes in definitive hosts of sub-Saharan Africa. Comparison of prevalence estimates derived from parasitological analysis at post-mortem examination and Mini-FLOTAC analysis showed non-significant differences indicating comparable results between the two techniques (P = 1.00 for S. mansoni; P = 0.85 for E. caproni; P = 0.83 for Plagiorchis sp.). A Bayesian model, applied to estimate the sensitivities of the two tests for the diagnosis of Schistosoma infections, indicated similar median posterior probabilities of 83.1% for Mini-FLOTAC technique and 82.9% for post-mortem examination (95% Bayesian credible intervals of 64.0–94.6% and 63.7–94.7%, respectively).ConclusionsOur results showed that the Mini-FLOTAC could be applied as an alternative diagnostic technique for the detection of the zoonotic S. mansoni and other trematodes in rodent reservoirs. The implementation of non-invasive diagnostics in wildlife would offer numerous advantages over lethal sampling methodologies, with potential impact on control strategies of zoonotic helminthiases in endemic areas of sub-Saharan Africa and on fostering a framework of animal use reduction in scientific practice.

Classical and Bayesian Estimation of Stress-Strength Reliability from Generalized Inverted Exponential Distribution based on Upper Records

This paper deals with the problem of classical and Bayesian estimation of stress-strength reliability (R=P(X<Y)) based on upper record values from generalized inverted exponential distribution (GIED). Hassan {et al.} (2018) discussed the maximum likelihood estimator (MLE) and Bayes estimator of $R$ by considering that the scale parameter to be known for defined distribution while we consider the case when all the parameters of GIED are unknown. In the classical approach, we have discussed MLE and uniformly minimum variance estimator (UMVUE). In Bayesian approach, we have considered the Bays estimator of R by considering the squared error loss function. Further, based on upper records, we have considered the Asymptotic confidence interval based on MLE, Bayesian credible interval and bootstrap confidence interval for $R$. Finally, Monte Carlo simulations and real data applications are being carried out for comparing the performances of the estimators of R.

On the Bayesian Analysis of Two-Component Mixture of Transmuted Weibull Distribution

Transmuted distributions are skewed distributions and recently attracted a great attention of researchers due totheir applications in reliability and statistics. In this article, our main focus is on the Bayesian estimation of two-component mixture of Transmuted Weibull Distribution (TWD) under type-I right censored sampling scheme. In order to estimate the unknown parameters, non-informative and informative priors under Squared Error Loss Function (SELF), Precautionary Loss Function (PLF) and Quadratic Loss Function (QLF) are assumed when computing the posterior estimations. In addition the Bayesian credible intervals (BCI) were also constructed. Markov Chain Monte Carlo (MCMC) technique is adopted to generate samples from the posterior distributions and in turn computing different posterior summaries including Bayes estimates(BEs), posterior risks(PRs) and Bayesian credible intervals (BCI). As an illustration comparision of these Bayes estimators are made through simulated under different loss functions in terms of their respective posterior risks assuming different sample sizes and censoring rates. Two real-life examples; the first being the survival times of hepatitis B & C patientswhile the second being the hole diameter of 12 mm and the sheet thickness is 3.15 mm are also discussed to illustrate the potential application of the proposed methodology.

Biodegradable polymer sirolimus-eluting stents versus durable polymer everolimus-eluting stents in patients with ST-segment elevation myocardial infarction (BIOSTEMI): a single-blind, prospective, randomised superiority trial

Newer-generation drug-eluting stents that combine ultrathin strut metallic platforms with biodegradable polymers might facilitate vascular healing and improve clinical outcomes in patients with acute myocardial infarction undergoing primary percutaneous coronary intervention (PCI) compared with contemporary thin strut second-generation drug-eluting stents. We did a randomised clinical trial to investigate the safety and efficacy of ultrathin strut biodegradable polymer sirolimus-eluting stents versus thin strut durable polymer everolimus-eluting stents in patients with acute ST-segment elevation myocardial infarction (STEMI) undergoing primary PCI. The BIOSTEMI trial was an investigator-initiated, multicentre, prospective, single-blind, randomised superiority trial at ten hospitals in Switzerland. Patients aged 18 years or older with acute STEMI who were referred for primary PCI were eligible to participate. Patients were randomly allocated (1:1) to either biodegradable polymer sirolimus-eluting stents or durable polymer everolimus-eluting stents. Central randomisation was done based on a computer-generated allocation sequence with variable block sizes of 2, 4, and 6, which was stratified by centre, diabetes status, and presence or absence of multivessel coronary artery disease, and concealed using a secure web-based system. Patients and treating physicians were aware of group allocations, whereas outcome assessors were masked to the allocated stent. The experimental stent (Orsiro; Biotronik; Bülach, Switzerland) consisted of an ultrathin strut cobalt-chromium metallic stent platform releasing sirolimus from a biodegradable polymer. The control stent (Xience Xpedition/Alpine; Abbott Vascular, Abbott Park, IL, USA) consisted of a thin strut cobalt-chromium stent platform that releases everolimus from a durable polymer. The primary endpoint was target lesion failure, a composite of cardiac death, target vessel myocardial reinfarction (Q-wave and non-Q-wave), and clinically-indicated target lesion revascularisation, within 12 months of the index procedure. All analyses were done with the individual participant as the unit of analysis and according to the intention-to-treat principle. The trial was registered with ClinicalTrials.gov, number NCT02579031. Between April 26, 2016, and March 9, 2018, we randomly assigned 1300 patients (1623 lesions) with acute myocardial infarction to treatment with biodegradable polymer sirolimus-eluting stents (649 patients and 816 lesions) or durable polymer everolimus-eluting stents (651 patients and 806 lesions). At 12 months, follow-up data were available for 614 (95%) patients treated with biodegradable polymer sirolimus-eluting stents and 626 (96%) patients treated with durable polymer everolimus-eluting stents. The primary composite endpoint of target lesion failure occurred in 25 (4%) of 649 patients treated with biodegradable polymer sirolimus-eluting stents and 36 (6%) of 651 patients treated with durable polymer everolimus-eluting stents (difference -1·6 percentage points; rate ratio 0·59, 95% Bayesian credibility interval 0·37-0·94; posterior probability of superiority 0·986). Cardiac death, target vessel myocardial reinfarction, clinically-indicated target lesion revascularisation, and definite stent thrombosis were similar between the two treatment groups in the 12 months of follow-up. In patients with acute STEMI undergoing primary PCI, biodegradable polymer sirolimus-eluting stents were superior to durable polymer everolimus-eluting stents with respect to target lesion failure at 1 year. This difference was driven by reduced ischaemia-driven target lesion revascularisation in patients treated with biodegradable polymer sirolimus-eluting stents compared with durable polymer everolimus-eluting stents. Biotronik.

Stress-Strength Reliability Estimation for the Type I Extreme-Value Distribution Based on Records

In this paper, we consider the stress-strength reliability for record data when the distribution of random stress and strength have the type I extreme-value distribution. First, classical inference methods, namely uniformly minimum variance unbiased estimate (UMVUE) and maximum likelihood estimate (MLE), are used for . Second, Bayesian inference of are considered for gamma priors assumption. When the common parameter of stress and strength variables is known, the exact Bayes estimate and Bayesian credible interval of are obtained. Markov Chain Monte Carlo (MCMC) method are used to derive the Bayes estimate and highest probability density (HPD) credible interval of when the common parameter is unknown. Finally, Monte Carlo simulations are performed to compare the performance of the obtained estimates. A real data set about the weather temperature is analyzed to illustrate the performances of the derived estimators in the paper.

Change in Albuminuria and GFR as End Points for Clinical Trials in Early Stages of CKD: A Scientific Workshop Sponsored by the National Kidney Foundation in Collaboration With the US Food and Drug Administration and European Medicines Agency

The US Food and Drug Administration (FDA) and European Medicines Agency (EMA) are currently willing to consider a 30% to 40% glomerular filtration rate (GFR) decline as a surrogate end point for kidney failure for clinical trials of kidney disease progression under appropriate conditions. However, these end points may not be practical for early stages of kidney disease. In March 2018, the National Kidney Foundation sponsored a scientific workshop in collaboration with the FDA and EMA to evaluate changes in albuminuria or GFR as candidate surrogate end points. Three parallel efforts were presented: meta-analyses of observational studies (cohorts), meta-analyses of clinical trials, and simulations of trial design. In cohorts, after accounting for measurement error, relationships between change in urinary albumin-creatinine ratio (UACR) or estimated GFR (eGFR) slope and the clinical outcome of kidney disease progression were strong and consistent. In trials, the posterior median R2 of treatment effects on the candidate surrogates with the clinical outcome was 0.47 (95% Bayesian credible interval [BCI], 0.02-0.96) for early change in UACR and 0.72 (95% BCI, 0.05-0.99) when restricted to baseline UACR>30mg/g, and 0.97 (95% BCI, 0.78-1.00) for total eGFR slope at 3 years and 0.96 (95% BCI, 0.63-1.00) for chronic eGFR slope (ie, the slope excluding the first 3 months from baseline, when there might be acute changes in eGFR). The magnitude of the relationships of changes in the candidate surrogates with risk for clinical outcome was consistent across cohorts and trials: a UACR reduction of 30% or eGFR slope reduction by 0.5 to 1.0mL/min/1.73m2 per year were associated with an HR of ∼0.7 for the clinical outcome in cohorts and trials. In simulations, using GFR slope as an end point substantially reduced the required sample size and duration of follow-up compared with the clinical end point when baseline eGFR was high, treatment effects were uniform, and there was no acute effect of the treatment. We conclude that both early change in albuminuria and GFR slope fulfill criteria for surrogacy for use as end points in clinical trials for chronic kidney disease progression under certain conditions, with stronger support for change in GFR than albuminuria. Implementation requires understanding conditions under which each surrogate is likely to perform well and restricting its use to those settings.

Patterns of immediate breast reconstruction in New South Wales, Australia: a population-based study.

BackgroundThe rate of immediate breast reconstruction (IBR) following mastectomy for breast cancer in Australia is low and varies between regions. To date, no previous Australian studies have examined IBR rates between all hospitals within a particular jurisdiction, despite hospitals being an important known contributor to variation in IBR rates in other countries.MethodsWe used cross‐classified random‐effects logistic regression models to examine the inter‐hospital variation in IBR rates by using data on 7961 women who underwent therapeutic mastectomy procedures in New South Wales (NSW) between January 2012 and June 2015. We derived IBR rates by patient‐, residential neighbourhood‐ and hospital‐related factors and investigated the underlying drivers for the variation in IBR.ResultsWe estimated the mean IBR rate across all hospitals performing mastectomy to be 17.1% (95% Bayesian credible interval (CrI) 12.1–23.1%) and observed wide inter‐hospital variation in IBR (variance 4.337, CrI 2.634–6.889). Older women, those born in Asian countries (odds ratio (OR) 0.5, CrI 0.4–0.6), residing in neighbourhoods with lower socioeconomic status (OR 0.7, CrI 0.5–0.8 for the most disadvantaged), and who underwent surgery in public hospitals (OR 0.4, CrI 0.1–1.0) were significantly less likely to have IBR. Women residing in non‐metropolitan areas and attending non‐metropolitan hospitals were significantly less likely to undergo IBR than their metropolitan counterparts attending metropolitan hospitals.ConclusionWide inter‐hospital variation raises concerns about potential inequities in access to IBR services and unmet demand in certain areas of NSW. Explaining the underlying drivers for IBR variation is the first step in identifying policy solutions to redress the issue.

Risk profiling of soil-transmitted helminth infection and estimated number of infected people in South Asia: A systematic review and Bayesian geostatistical Analysis

BackgroundIn South Asia, hundreds of millions of people are infected with soil-transmitted helminths (Ascaris lumbricoides, hookworm, and Trichuris trichiura). However, high-resolution risk profiles and the estimated number of people infected have yet to be determined. In turn, such information will assist control programs to identify priority areas for allocation of scarce resource for the control of soil-transmitted helminth infection.MethodologyWe pursued a systematic review to identify prevalence surveys pertaining to soil-transmitted helminth infections in four mainland countries (i.e., Bangladesh, India, Nepal, and Pakistan) of South Asia. PubMed and ISI Web of Science were searched from inception to April 25, 2019, without restriction of language, study design, and survey date. We utilized Bayesian geostatistical models to identify environmental and socioeconomic predictors, and to estimate infection risk at high spatial resolution across the study region.Principal findingsA total of 536, 490, and 410 georeferenced surveys were identified for A. lumbricoides, hookworm, and T. trichiura, respectively. We estimate that 361 million people (95% Bayesian credible interval (BCI) 331–395 million), approximately one-quarter of the South Asia population, was infected with at least one soil-transmitted helminth species in 2015. A. lumbricoides was the predominant species. Moderate to high prevalence (>20%) of any soil-transmitted helminth infection was predicted in the northeastern part and some northern areas of the study region, as well as the southern coastal areas of India. The annual treatment needs for the school-age population requiring preventive chemotherapy was estimated at 165 million doses (95% BCI: 146–185 million).Conclusions/significanceOur risk maps provide an overview of the geographic distribution of soil-transmitted helminth infection in four mainland countries of South Asia and highlight the need for up-to-date surveys to accurately evaluate the disease burden in the region.