A more powerful test for three-arm non-inferiority via risk difference: Frequentist and Bayesian approaches

2021 ◽  
pp. 1-23
Author(s):  
Erina Paul ◽  
Ram C. Tiwari ◽  
Shrabanti Chowdhury ◽  
Samiran Ghosh
Keyword(s):  
Risk Difference ◽  
Bayesian Approaches ◽  
Powerful Test

Translocation Relative to Range

Methodology ◽  
2008 ◽  
Vol 4 (3) ◽  
pp. 132-138 ◽  
Author(s):  
Michael Höfler
Keyword(s):  
Risk Difference ◽  
Binary Outcomes ◽  
Number Needed To Treat ◽  
Likert Scales ◽  
Psychological Science ◽  
The Absolute ◽  
The Difference ◽  
Variance Parameters ◽  
Standardized Index ◽  
Maximum Possible Magnitude

A standardized index for effect intensity, the translocation relative to range (TRR), is discussed. TRR is defined as the difference between the expectations of an outcome under two conditions (the absolute increment) divided by the maximum possible amount for that difference. TRR measures the shift caused by a factor relative to the maximum possible magnitude of that shift. For binary outcomes, TRR simply equals the risk difference, also known as the inverse number needed to treat. TRR ranges from –1 to 1 but is – unlike a correlation coefficient – a measure for effect intensity, because it does not rely on variance parameters in a certain population as do effect size measures (e.g., correlations, Cohen’s d). However, the use of TRR is restricted on outcomes with fixed and meaningful endpoints given, for instance, for meaningful psychological questionnaires or Likert scales. The use of TRR vs. Cohen’s d is illustrated with three examples from Psychological Science 2006 (issues 5 through 8). It is argued that, whenever TRR applies, it should complement Cohen’s d to avoid the problems related to the latter. In any case, the absolute increment should complement d.

Measuring Effectiveness

2018 ◽  
Author(s):  
Jacob Stegenga
Keyword(s):  
Outcome Measures ◽  
Relative Risk Reduction ◽  
Drug Approval ◽  
Target Population ◽  
Risk Difference ◽  
General Context ◽  
Measuring Instruments ◽  
Clinical Settings ◽  
Medical Interventions ◽  
Regulatory Standards

There are three methodological challenges to measuring the effectiveness of medical interventions: the choice of good measuring instruments, the use of appropriate analytic measures, and the use of a reliable method of extrapolating measures from an experimental context to a more general context. In practice each of these challenges contributes to overestimating the effectiveness of medical interventions. These challenges suggest corrective principles. The instruments employed in clinical research should measure patient-relevant and disease-specific parameters. Effectiveness always should be measured and reported using absolute outcome measures (such as ‘risk difference’), and we should employ caution when interpreting relative outcome measures (such as ‘relative risk reduction’). Extrapolating from research settings to clinical settings should more rigorously take into account possible ways in which interventions can fail to be effective in a target population. Current regulatory standards for drug approval are insufficient to manage these problems of measurement.

scholarly journals Bayesian graphical models for modern biological applications

2021 ◽  
Author(s):  
Yang Ni ◽  
Veerabhadran Baladandayuthapani ◽  
Marina Vannucci ◽  
Francesco C. Stingo
Keyword(s):  
Graphical Models ◽  
Cancer Genomics ◽  
Graph Structure ◽  
Biological Processes ◽  
Limited Sample ◽  
Large Networks ◽  
Bayesian Approaches ◽  
Complex Sampling ◽  
Complex Dependence ◽  
Bayesian Graphical Models

AbstractGraphical models are powerful tools that are regularly used to investigate complex dependence structures in high-throughput biomedical datasets. They allow for holistic, systems-level view of the various biological processes, for intuitive and rigorous understanding and interpretations. In the context of large networks, Bayesian approaches are particularly suitable because it encourages sparsity of the graphs, incorporate prior information, and most importantly account for uncertainty in the graph structure. These features are particularly important in applications with limited sample size, including genomics and imaging studies. In this paper, we review several recently developed techniques for the analysis of large networks under non-standard settings, including but not limited to, multiple graphs for data observed from multiple related subgroups, graphical regression approaches used for the analysis of networks that change with covariates, and other complex sampling and structural settings. We also illustrate the practical utility of some of these methods using examples in cancer genomics and neuroimaging.

scholarly journals Perioperative liberal versus restrictive fluid strategies and postoperative outcomes: a systematic review and metanalysis on randomised-controlled trials in major abdominal elective surgery

Critical Care ◽  
2021 ◽  
Vol 25 (1) ◽  
Author(s):  
Antonio Messina ◽  
Chiara Robba ◽  
Lorenzo Calabrò ◽  
Daniel Zambelli ◽  
Francesca Iannuzzi ◽  
...  
Keyword(s):  
Systematic Review ◽  
Postoperative Complications ◽  
Randomised Controlled Trials ◽  
Elective Surgery ◽  
Fluid Management ◽  
Risk Difference ◽  
Controlled Trials ◽  
Perioperative Fluid Management ◽  
Liberal Approach ◽  
Randomised Controlled

Abstract Background Postoperative complications impact on early and long-term patients’ outcome. Appropriate perioperative fluid management is pivotal in this context; however, the most effective perioperative fluid management is still unclear. The enhanced recovery after surgery pathways recommend a perioperative zero-balance, whereas recent findings suggest a more liberal approach could be beneficial. We conducted this trial to address the impact of restrictive vs. liberal fluid approaches on overall postoperative complications and mortality. Methods Systematic review and meta-analysis, including randomised controlled trials (RCTs). We performed a systematic literature search using MEDLINE (via Ovid), EMBASE (via Ovid) and the Cochrane Controlled Clinical trials register databases, published from 1 January 2000 to 31 December 2019. We included RCTs enrolling adult patients undergoing elective abdominal surgery and comparing the use of restrictive/liberal approaches enrolling at least 15 patients in each subgroup. Studies involving cardiac, non-elective surgery, paediatric or obstetric surgeries were excluded. Results After full-text examination, the metanalysis finally included 18 studies and 5567 patients randomised to restrictive (2786 patients; 50.0%) or liberal approaches (2780 patients; 50.0%). We found no difference in the occurrence of severe postoperative complications between restrictive and liberal subgroups [risk difference (95% CI) = 0.009 (− 0.02; 0.04); p value = 0.62; I2 (95% CI) = 38.6% (0–66.9%)]. This result was confirmed also in the subgroup of five studies having a low overall risk of bias. The liberal approach was associated with lower overall renal major events, as compared to the restrictive [risk difference (95% CI) = 0.06 (0.02–0.09); p value  = 0.001]. We found no difference in either early (p value  = 0.33) or late (p value  = 0.22) postoperative mortality between restrictive and liberal subgroups Conclusions In major abdominal elective surgery perioperative, the choice between liberal or restrictive approach did not affect overall major postoperative complications or mortality. In a subgroup analysis, a liberal as compared to a restrictive perioperative fluid policy was associated with lower overall complication renal major events, as compared to the restrictive. Trial Registration CRD42020218059; Registration: February 2020, https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=218059.

scholarly journals The Association of Intraoperative driving pressure with postoperative pulmonary complications in open versus closed abdominal surgery patients – a posthoc propensity score–weighted cohort analysis of the LAS VEGAS study

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Guido Mazzinari ◽  
◽  
Ary Serpa Neto ◽  
Sabrine N. T. Hemmes ◽  
Goran Hedenstierna ◽  
...  
Keyword(s):  
Propensity Score ◽  
Adverse Events ◽  
Abdominal Surgery ◽  
Las Vegas ◽  
Cohort Analysis ◽  
Risk Difference ◽  
Pulmonary Complications ◽  
Driving Pressure ◽  
Postoperative Pulmonary Complications ◽  
Open Abdominal Surgery

Abstract Background It is uncertain whether the association of the intraoperative driving pressure (ΔP) with postoperative pulmonary complications (PPCs) depends on the surgical approach during abdominal surgery. Our primary objective was to determine and compare the association of time–weighted average ΔP (ΔPTW) with PPCs. We also tested the association of ΔPTW with intraoperative adverse events. Methods Posthoc retrospective propensity score–weighted cohort analysis of patients undergoing open or closed abdominal surgery in the ‘Local ASsessment of Ventilatory management during General Anaesthesia for Surgery’ (LAS VEGAS) study, that included patients in 146 hospitals across 29 countries. The primary endpoint was a composite of PPCs. The secondary endpoint was a composite of intraoperative adverse events. Results The analysis included 1128 and 906 patients undergoing open or closed abdominal surgery, respectively. The PPC rate was 5%. ΔP was lower in open abdominal surgery patients, but ΔPTW was not different between groups. The association of ΔPTW with PPCs was significant in both groups and had a higher risk ratio in closed compared to open abdominal surgery patients (1.11 [95%CI 1.10 to 1.20], P <  0.001 versus 1.05 [95%CI 1.05 to 1.05], P <  0.001; risk difference 0.05 [95%CI 0.04 to 0.06], P <  0.001). The association of ΔPTW with intraoperative adverse events was also significant in both groups but had higher odds ratio in closed compared to open abdominal surgery patients (1.13 [95%CI 1.12– to 1.14], P <  0.001 versus 1.07 [95%CI 1.05 to 1.10], P <  0.001; risk difference 0.05 [95%CI 0.030.07], P <  0.001). Conclusions ΔP is associated with PPC and intraoperative adverse events in abdominal surgery, both in open and closed abdominal surgery. Trial registration LAS VEGAS was registered at clinicaltrials.gov (trial identifier NCT01601223).

Nasal High-Frequency Oscillatory Ventilation in Preterm Infants with Moderate Respiratory Distress Syndrome: A Multicenter Randomized Clinical Trial

Neonatology ◽  
2021 ◽  
pp. 1-7
Author(s):  
Xingwang Zhu ◽  
Zhichun Feng ◽  
Chengjun Liu ◽  
Liping Shi ◽  
Yuan Shi ◽  
...  
Keyword(s):  
Mechanical Ventilation ◽  
Respiratory Distress Syndrome ◽  
Preterm Infants ◽  
High Frequency ◽  
Primary Outcome ◽  
Distress Syndrome ◽  
Invasive Mechanical Ventilation ◽  
Risk Difference ◽  
High Frequency Oscillatory Ventilation ◽  
High Frequency Oscillatory

<b><i>Objective:</i></b> To determine whether nasal high-frequency oscillatory ventilation (NHFOV) as a primary mode of respiratory support as compared with nasal continuous airway pressure (NCPAP) will reduce the need for invasive mechanical ventilation in preterm infants (26<sup>0/7</sup>–33<sup>6/7</sup> weeks of gestational age [GA]) with respiratory distress syndrome (RDS). <b><i>Methods:</i></b> This multicenter randomized controlled trial was conducted in 18 tertiary neonatal intensive care units in China. A total of 302 preterm infants born at a GA of 26<sup>0/7</sup>–33<sup>6/7</sup> weeks with a diagnosis of RDS were randomly assigned to either the NCPAP (<i>n</i> = 150) or the NHFOV (<i>n</i> = 152) group. The primary outcome was the need for invasive mechanical ventilation during the first 7 days after birth. <b><i>Results:</i></b> Treatment failure occurred in 15 of 152 infants (9.9%) in the ­NHFOV group and in 26 of 150 infants (17.3%) in the NCPAP group (95% CI of risk difference: −15.2 to 0.4, <i>p =</i> 0.06). In the subgroup analysis, NHFOV resulted in a significantly lower rate of treatment failure than did NCPAP in the strata of 26<sup>+0/7</sup>–29<sup>+6/7</sup>weeks of GA (11.9 vs. 32.4%, 95% CI of risk difference: −39.3 to −1.7, <i>p =</i> 0.03) and birth weight &#x3c;1,500 g (10.4 vs. 29.6%, 95% CI of risk difference: −33.8 to −4.6, <i>p =</i> 0.01). The rate of thick secretions causing an airway obstruction was higher in the NHFOV group than in the NCPAP group (13.8 vs. 5.3%, 95% CI of risk difference: 1.9–15.1, <i>p =</i> 0.01). No significant differences in other secondary outcomes were found between the NHFOV and NCPAP groups. <b><i>Conclusions:</i></b> NHFOV was not superior to NCPAP with regard to the primary outcome when applied as the primary respiratory support for RDS in infants between 26<sup>+0/7</sup> and 33<sup>+6/7</sup> weeks of GA. In the subgroup analysis, NHFOV seemed to improve effectiveness than NCPAP in preterm infants &#x3c;30 weeks of GA.

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