scholarly journals MD4 ERROR PROPAGATION FOR SIMULATED TREATMENT COMPARISONS

2020 ◽  
Vol 23 ◽  
pp. S8
Author(s):  
E. Mackay ◽  
J. Slater ◽  
P. Arora ◽  
K. Thorlund ◽  
A. Beliveau ◽  
...  
Keyword(s):  
Error Propagation ◽  
Treatment Comparisons

Error propagation in simulated treatment comparisons for multiple myeloma: Results from a simulation.

2020 ◽  
Vol 38 (15_suppl) ◽  
pp. e20523-e20523
Author(s):  
Eric Mackay ◽  
Justin Slater ◽  
Paul Arora ◽  
Kristian Thorlund ◽  
Audrey Beliveau ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Treatment Effect ◽  
Comparative Effectiveness ◽  
Error Propagation ◽  
Covariate Adjustment ◽  
Relative Treatment Effect ◽  
Kaplan Meier ◽  
Adjustment Term ◽  
Treatment Comparisons ◽  
True Treatment Effect

e20523 Background: Comparing the effectiveness of multiple myeloma treatments presents a challenge due to the limited number of head-to-head trials with which to conduct indirect treatment comparisons. This is particularly true when subgroup analysis is of interest. In comparative effectiveness research Simulated Treatment Comparisons (STCs) are becoming increasingly common in the absence of head-to-head trials. STCs use estimates from limited IPD to adjust for covariate imbalance between trials, however the uncertainty from these estimates is generally ignored when estimating relative treatment effects. This study demonstrates the need to account for this uncertainty when conducting STCs for indications such as multiple myeloma. We introduce an STC method that accounts for the uncertainty due to covariate adjustment, and demonstrate its effectiveness via simulation. Methods: We simulated two single arm studies (N = 300 for both), each containing age and overall survival. We assume study 1 has individual patient data available, and study 2 only has aggregate age data and a digitized Kaplan-Meier curve. We compute a covariate adjustment term based on the mean age difference between the studies and the age coefficients from fitting a parametric survival model to the observed study 1 IPD. We then estimate the variance of this adjustment term via bootstrapping and incorporate this uncertainty into a Bayesian STC model which estimates the relative treatment effect for the two study datasets converted to a digitized Kaplan-Meier format. Results: The proportion of 95% credible intervals (CrI) that captured the true treatment effect was 86.8% without error propagation, whereas 92.0% of CrI’s captured the true treatment with error propagation. 94.9% of CrI’s contained the true treatment effect when using survival regression with the complete IPD. Conclusions: Failing to account for uncertainty from the covariate adjustment when conducting simulated treatment comparisons generally leads to underestimating the uncertainty of the relative treatment effect. This method better captures the uncertainty introduced when conducting an STC and has the potential to yield more reliable estimates of the comparative effectiveness of multiple myeloma treatments.

Vapour-liquid equilibrium in the ternary system cyclohexane-acetic acid-propionic acid

1989 ◽  
Vol 54 (11) ◽  
pp. 2840-2847 ◽  
Author(s):  
Ivona Malijevská ◽  
Alena Maštalková ◽  
Marie Sýsová
Keyword(s):  
Acetic Acid ◽  
Ternary System ◽  
Propionic Acid ◽  
Activity Coefficients ◽  
Error Propagation ◽  
Analytical Techniques ◽  
Liquid Equilibrium ◽  
Consistency Test ◽  
Propagation Law ◽  
Equilibrium Data

Isobaric equilibrium data (P = 101.3 kPa) for the system cyclohexane-acetic acid-propionic acid have been measured by two different analytical techniques. Activity coefficients calculated by simultaneous solving of equations for the chemical and phase equilibria were subjected to a consistency test based on inaccuracies determined from the error propagation law, and were correlated by Wilson’s equation. The activity coefficients measured were compared with those calculated from binary vapour-liquid equilibrium data and with values predicted by the UNIFAC method.

An Enhanced Two Stage MMSE Equalizer for Coded FBMC/OQAM Systems

2019 ◽  
Vol 10 (1) ◽  
pp. 69-82 ◽  
Author(s):  
Mohammad Rizk Assaf ◽  
Abdel-Nasser Assimi
Keyword(s):  
Error Propagation ◽  
Channel Model ◽  
Error Correcting Codes ◽  
Two Stage ◽  
Probability Of Error ◽  
Second Stage ◽  
Different Types ◽  
Mmse Equalizer ◽  
And Performance ◽  
Ici Cancellation

In this article, the authors investigate the enhanced two stage MMSE (TS-MMSE) equalizer in bit-interleaved coded FBMC/OQAM system which gives a tradeoff between complexity and performance, since error correcting codes limits error propagation, so this allows the equalizer to remove not only ICI but also ISI in the second stage. The proposed equalizer has shown less design complexity compared to the other MMSE equalizers. The obtained results show that the probability of error is improved where SNR gain reaches 2 dB measured at BER compared with ICI cancellation for different types of modulation schemes and ITU Vehicular B channel model. Some simulation results are provided to illustrate the effectiveness of the proposed equalizer.

scholarly journals In vitro responses to platelet-rich-plasma are associated with variable clinical outcomes in patients with knee osteoarthritis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Habib Zahir ◽  
Bijan Dehghani ◽  
Xiaoning Yuan ◽  
Yurii Chinenov ◽  
Christine Kim ◽  
...  
Keyword(s):  
Knee Osteoarthritis ◽  
Clinical Outcomes ◽  
Inflammatory Responses ◽  
Platelet Rich Plasma ◽  
Autologous Blood ◽  
Limited Information ◽  
Knee Oa ◽  
Patient Reported ◽  
Treatment Comparisons

AbstractAutologous blood-derived products such as platelet-rich plasma (PRP) are widely used to treat musculoskeletal conditions, including knee osteoarthritis (OA). However, the clinical outcomes after PRP administration are often variable, and there is limited information about the specific characteristics of PRP that impact bioactivity and clinical responses. In this study, we aimed to develop an integrative workflow to evaluate responses to PRP in vitro, and to assess if the in vitro responses to PRP are associated with the PRP composition and clinical outcomes in patients with knee OA. To do this, we used a coculture system of macrophages and fibroblasts paired with transcriptomic analyses to comprehensively characterize the modulation of inflammatory responses by PRP in vitro. Relying on patient-reported outcomes and achievement of minimal clinically important differences in OA patients receiving PRP injections, we identified responders and non-responders to the treatment. Comparisons of PRP from these patient groups allowed us to identify differences in the composition and in vitro activity of PRP. We believe that our integrative workflow may enable the development of targeted approaches that rely on PRP and other orthobiologics to treat musculoskeletal pathologies.

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