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Respirology (Carlton, Vic.) Nov 2014Over the past decade, several non-surgical and minimally invasive bronchoscopic lung volume reduction (BLVR) techniques have been developed to treat patients with severe... (Review)
Review
Over the past decade, several non-surgical and minimally invasive bronchoscopic lung volume reduction (BLVR) techniques have been developed to treat patients with severe chronic obstructive pulmonary disease (COPD). BLVR can be significantly efficacious, suitable for a broad cohort of patients, and associated with a solid safety profile at a reasonable expense. The introduction of BLVR is also expected to accelerate the further development of interventional pulmonology worldwide. Recently, results from clinical studies on BLVR techniques have been published, providing valuable information about the procedure's indications, contraindications, patient-selection criterion and outcomes. BLVR utilizing one-way endobronchial valves is gaining momentum as an accepted treatment in regular medical practice because of the identification of best responders. Patients with a heterogeneous emphysema distribution and without inter-lobar collateral ventilation show encouraging results. Furthermore, for patients with collateral ventilation, who are not considered candidates for valve treatment, and for patients with homogeneous emphysema, the introduction of lung volume reduction coil treatment is a promising solution. Moreover, with the development of newer treatment modalities, that is, biochemical sealant and thermal water vapor, the potential to treat emphysema irrespective of collateral flow, may be further increased. Nevertheless, patient selection for BLVR treatment will be crucial for the procedure's success and should be performed using a multidisciplinary team approach. Consequently, BLVR needs to be concentrated in high-volume centres that will offer better quality and experience with treatment challenges and adverse events. This review gives a general overview of BLVR from an expert and scientific perspective.
Topics: Bronchoscopy; Humans; Outcome Assessment, Health Care; Patient Selection; Pneumonectomy; Prognosis; Pulmonary Disease, Chronic Obstructive
PubMed: 25124070
DOI: 10.1111/resp.12362 -
Clinics in Podiatric Medicine and... Jan 2016Whether performed as a primary procedure or used to augment and support osseous reconstruction, tendon transfers are a key skill for the foot and ankle surgeon.... (Review)
Review
Whether performed as a primary procedure or used to augment and support osseous reconstruction, tendon transfers are a key skill for the foot and ankle surgeon. Understanding the biomechanics preoperative and postoperatively is essential in performing appropriate procedures and in supporting patients through the rehabilitation process. Often the complexity of tendon transfer surgery is lost because it is deemed a soft tissue procedure and in theory should be less complex than osseous procedures. However, the dynamic nature of musculature and tendons require a deeper understanding of surgical and biomechanical concepts.
Topics: Foot; Humans; Muscle Strength; Patient Selection; Range of Motion, Articular; Tendon Transfer; Tensile Strength
PubMed: 26590719
DOI: 10.1016/j.cpm.2015.06.001 -
Statistics in Medicine Nov 2021In clinical trials, sample size re-estimation is often conducted at interim. The purpose is to determine whether the study will achieve study objectives if the observed...
In clinical trials, sample size re-estimation is often conducted at interim. The purpose is to determine whether the study will achieve study objectives if the observed treatment effect at interim preserves till end of the study. A traditional approach is to conduct a conditional power analysis for sample size only based on observed treatment effect. This approach, however, does not take into consideration the variabilities of (i) the observed (estimate) treatment effect and (ii) the observed (estimate) variability associated with the treatment effect. Thus, the resultant re-estimated sample sizes may not be robust and hence may not be reliable. In this article, a couple of methods are proposed, namely, adjusted effect size (AES) approach and iterated expectation/variance (IEV) approach, which can account for the variability associated with the observed responses at interim. The proposed methods provide interval estimates of sample size required for the intended trial, which is useful for making critical go/no go decision. Statistical properties of the proposed methods are evaluated in terms of controlling of type I error rate and statistical power. The results show that traditional approach performs poorly in controlling type I error inflation, whereas IEV approach has the best performance in most cases. Additionally, all re-estimation approaches can keep the statistical power over 80 ; especially, IEV approach's statistical power, using adjusted significance level, is over 95 . However, IEV approach may lead to a greater increment in sample size when detecting a smaller effect size. In general, IEV approach is effective when effect size is large; otherwise, AES approach is more suitable for controlling type I error rate and keep power over 80 with a more reasonable re-estimated sample size.
Topics: Clinical Trials as Topic; Humans; Research Design; Sample Size
PubMed: 34433225
DOI: 10.1002/sim.9175 -
Research Synthesis Methods May 2023We developed metadta, a flexible, robust, and user-friendly statistical procedure that fuses established and innovative statistical methods for meta-analysis,... (Meta-Analysis)
Meta-Analysis Review
We developed metadta, a flexible, robust, and user-friendly statistical procedure that fuses established and innovative statistical methods for meta-analysis, meta-regression, and network meta-analysis of diagnostic test accuracy studies in Stata. Using data from published meta-analyses, we validate metadta by comparing and contrasting its features and output to popular procedures dedicated to the meta-analysis of diagnostic test accuracy studies; (midas [Stata], metandi [Stata], metaDTA [web application], mada [R], and MetaDAS [SAS]). We also demonstrate how to perform network meta-analysis with metadta, for which no alternative procedure is dedicated to network meta-analysis of diagnostic test accuracy data in the frequentist framework. metadta generated consistent estimates in simple and complex diagnostic test accuracy data sets. We expect its availability to stimulate better statistical practice in the evidence synthesis of diagnostic test accuracy studies.
Topics: Software; Research Design; Network Meta-Analysis; Diagnostic Tests, Routine
PubMed: 36999350
DOI: 10.1002/jrsm.1634 -
International Journal of Environmental... Oct 2022Sample size estimation is a fundamental element of a clinical trial, and a binomial experiment is the most common situation faced in clinical trial design. A Bayesian...
Sample size estimation is a fundamental element of a clinical trial, and a binomial experiment is the most common situation faced in clinical trial design. A Bayesian method to determine sample size is an alternative solution to a frequentist design, especially for studies conducted on small sample sizes. The Bayesian approach uses the available knowledge, which is translated into a prior distribution, instead of a point estimate, to perform the final inference. This procedure takes the uncertainty in data prediction entirely into account. When objective data, historical information, and literature data are not available, it may be indispensable to use expert opinion to derive the prior distribution by performing an elicitation process. Expert elicitation is the process of translating expert opinion into a prior probability distribution. We investigated the estimation of a binomial sample size providing a generalized version of the average length, coverage criteria, and worst outcome criterion. The original method was proposed by Joseph and is defined in a parametric framework based on a Beta-Binomial model. We propose a more flexible approach for binary data sample size estimation in this theoretical setting by considering parametric approaches (Beta priors) and semiparametric priors based on B-splines.
Topics: Sample Size; Bayes Theorem; Research Design; Models, Statistical; Probability
PubMed: 36361129
DOI: 10.3390/ijerph192114245 -
Academic Radiology May 2018A systematic review is a comprehensive search, critical evaluation, and synthesis of all the relevant studies on a specific (clinical) topic that can be applied to the... (Review)
Review
A systematic review is a comprehensive search, critical evaluation, and synthesis of all the relevant studies on a specific (clinical) topic that can be applied to the evaluation of diagnostic and screening imaging studies. It can be a qualitative or a quantitative (meta-analysis) review of available literature. A meta-analysis uses statistical methods to combine and summarize the results of several studies. In this review, a 12-step approach to performing a systematic review (and meta-analysis) is outlined under the four domains: (1) Problem Formulation and Data Acquisition, (2) Quality Appraisal of Eligible Studies, (3) Statistical Analysis of Quantitative Data, and (4) Clinical Interpretation of the Evidence. This review is specifically geared toward the performance of a systematic review and meta-analysis of diagnostic test accuracy (imaging) studies.
Topics: Humans; Diagnostic Imaging; Meta-Analysis as Topic; Research Design; Systematic Reviews as Topic
PubMed: 29371119
DOI: 10.1016/j.acra.2017.12.007 -
The Surgical Clinics of North America Aug 2000At present, laparoscopic bariatric surgery is a controversial topic among bariatric and laparoscopic surgeons. Although difficult to perform, the traditional procedures... (Review)
Review
At present, laparoscopic bariatric surgery is a controversial topic among bariatric and laparoscopic surgeons. Although difficult to perform, the traditional procedures used for treating severe obesity are now being performed successfully using a laparoscopic approach. In addition, a new procedure, adjustable gastric banding, has been used in Europe; however, it lacks US Food and Drug Administration approval and adequate scientific follow-up data about long-term effectiveness. Appropriate patient selection and adherence to the principles that have been learned by experience through open bariatric surgery remain of paramount importance for the success of laparoscopic bariatric operations.
Topics: Gastric Bypass; Gastroenterostomy; Gastroplasty; Humans; Laparoscopy; Obesity, Morbid; Patient Selection; Postoperative Complications; Punctures; Surgical Stapling
PubMed: 10987034
DOI: 10.1016/s0039-6109(05)70223-1 -
Journal of Hospital Medicine Apr 2021As general internists practicing in the inpatient setting, hospitalists at many institutions are expected to perform invasive bedside procedures, as defined by... (Review)
Review
BACKGROUND
As general internists practicing in the inpatient setting, hospitalists at many institutions are expected to perform invasive bedside procedures, as defined by professional standards. In reality, hospitalists are doing fewer procedures and increasingly are referring to specialists, which threatens their ability to maintain procedural skills. The discrepancy between expectations and reality, especially when hospitalists may be fully credentialed to perform procedures, poses significant risks to patients because of morbidity and mortality associated with complications, some of which derive from practitioner inexperience.
METHODS
We performed a structured search of the peer-reviewed literature to identify articles focused on hospitalists performing procedures.
RESULTS
Our synthesis of the literature characterizes contributors to hospitalists' procedural competency and discusses: (1) temporal trends for procedures performed by hospitalists and their associated referral patterns, (2) data comparing use and clinical outcomes of procedures performed by hospitalists compared with specialists, (3) the lack of nationwide standardization of hospitalist procedural training and credentialing, and (4) the role of medical procedure services, although limited in supportive evidence, in concentrating procedural skill and mitigating risk in the hands of a few well-trained hospitalists.
CONCLUSION
We conclude with recommendations for hospital medicine groups to ensure the safety of hospitalized patients undergoing bedside procedures.
Topics: Credentialing; Hospital Medicine; Hospitalists; Hospitalization; Humans; Referral and Consultation
PubMed: 33734979
DOI: 10.12788/jhm.3590 -
Trials Aug 2015Stepped wedge trials (SWTs) can be considered as a variant of a clustered randomised trial, although in many ways they embed additional complications from the point of... (Review)
Review
BACKGROUND
Stepped wedge trials (SWTs) can be considered as a variant of a clustered randomised trial, although in many ways they embed additional complications from the point of view of statistical design and analysis. While the literature is rich for standard parallel or clustered randomised clinical trials (CRTs), it is much less so for SWTs. The specific features of SWTs need to be addressed properly in the sample size calculations to ensure valid estimates of the intervention effect.
METHODS
We critically review the available literature on analytical methods to perform sample size and power calculations in a SWT. In particular, we highlight the specific assumptions underlying currently used methods and comment on their validity and potential for extensions. Finally, we propose the use of simulation-based methods to overcome some of the limitations of analytical formulae. We performed a simulation exercise in which we compared simulation-based sample size computations with analytical methods and assessed the impact of varying the basic parameters to the resulting sample size/power, in the case of continuous and binary outcomes and assuming both cross-sectional data and the closed cohort design.
RESULTS
We compared the sample size requirements for a SWT in comparison to CRTs based on comparable number of measurements in each cluster. In line with the existing literature, we found that when the level of correlation within the clusters is relatively high (for example, greater than 0.1), the SWT requires a smaller number of clusters. For low values of the intracluster correlation, the two designs produce more similar requirements in terms of total number of clusters. We validated our simulation-based approach and compared the results of sample size calculations to analytical methods; the simulation-based procedures perform well, producing results that are extremely similar to the analytical methods. We found that usually the SWT is relatively insensitive to variations in the intracluster correlation, and that failure to account for a potential time effect will artificially and grossly overestimate the power of a study.
CONCLUSIONS
We provide a framework for handling the sample size and power calculations of a SWT and suggest that simulation-based procedures may be more effective, especially in dealing with the specific features of the study at hand. In selected situations and depending on the level of intracluster correlation and the cluster size, SWTs may be more efficient than comparable CRTs. However, the decision about the design to be implemented will be based on a wide range of considerations, including the cost associated with the number of clusters, number of measurements and the trial duration.
Topics: Computer Simulation; Data Interpretation, Statistical; Humans; Models, Statistical; Patient Selection; Randomized Controlled Trials as Topic; Research Design; Sample Size; Time Factors
PubMed: 26282553
DOI: 10.1186/s13063-015-0840-9 -
Minerva Cardiology and Angiology Dec 2021Percutaneous non-valvular structural interventions, encompassing patent foramen ovale, atrial or ventricular septal defect closure and left atrial appendage closure, are... (Review)
Review
Percutaneous non-valvular structural interventions, encompassing patent foramen ovale, atrial or ventricular septal defect closure and left atrial appendage closure, are usually performed in young and healthy patients and represent a valid alternative to pharmacological or surgical interventions. In order to minimize procedural and device related complications, a careful pre-procedural planning together with an accurate intra-procedural imaging are crucial to improve patient's outcome. In this article, we review currently available evidence on patient selection, procedural planning and interventional guidance helping physician to determine who will derive the most benefit from the procedure.
Topics: Cardiac Catheterization; Cardiac Surgical Procedures; Foramen Ovale, Patent; Heart Septal Defects, Ventricular; Humans; Patient Selection
PubMed: 34870383
DOI: 10.23736/S2724-5683.21.05696-9