Severe Sepsis: The Fragile Anatomy of Crude Mortality

Author(s):  
Nicole C Vissichelli ◽  
Adam P Sima ◽  
Richard P Wenzel

Abstract Clinical trials of severe sepsis that target crude (total) mortality as an end point do not have sufficient power to detect differences in mortality due to the intervention. We aim to discuss the importance of including the subcomponents of crude mortality in study design; estimate how sample size requirements change based on the proportion of attributable mortality; and how minor changes from predicted outcomes can affect results. We derived statistical curves to illustrate our points.

2020 ◽  
Author(s):  
Ben-nian Huo ◽  
Mao-lin Ai ◽  
Yun-tao Jia ◽  
Yao LIU ◽  
Nan-ge Yin ◽  
...  

Abstract Background: Although discontinuation is common in clinical trials, no study has been conducted to analyse the current situation and reasons for the suspension or discontinuation of drug clinical trials in China. This study aims to analyse the general characteristics and reasons for the discontinuation of registered clinical trials in mainland China and to identify the associated factors.Methods: Trials with a status of terminated or stopped in the Drug Trial Registration and Information Publication Platform before March 31, 2020, were classified as discontinued trials and included in the analysis. Information related to researchers, studied drugs, the trials and the reasons for discontinuation were recorded. Fisher’s exact and χ2 tests were used to examine the associations of trial characteristics with different issues related to trial discontinuation. Results: Three hundred and twelve discontinued trials were included in this study. The studied drugs were mainly chemical drugs [229 (73.4%)]. The indications of the studied drugs were mainly neoplasms [77 (24.7%)]. The study type was mainly bioequivalence studies [97 (31.1%)]. More than half [177 (56.7%)] of the trials were discontinued because of trial issues, among which the main causes were negative results [69 (22.1%)], protocol issues [41 (13.1%)], and poor recruitment [35 (11.2%)]. Ninety-five (30.4%), 15 (4.8%) and 26 (8.3%) trials were discontinued because of sponsor issues, research centre issues and administration issues, respectively. Study design, blinding status, number of centres, planned sample size and whether participants had been enrolled may have been associated with one to three of the issues related to trial discontinuation.Conclusions: Discontinuation of clinical trials was commonly due to trial issues, sponsor issues, research centre issues and administration issues, such as negative results, and protocol issues. Study design, the number of centres, and sample size may be related to the discontinuation of trials. Careful study designs, smart business decisions, sufficient preparation of supplies such as the research drugs, and whether research centres have enough availability and patients are factors that should be considered before conducting trials.


1990 ◽  
Vol 29 (03) ◽  
pp. 243-246 ◽  
Author(s):  
M. A. A. Moussa

AbstractVarious approaches are considered for adjustment of clinical trial size for patient noncompliance. Such approaches either model the effect of noncompliance through comparison of two survival distributions or two simple proportions. Models that allow for variation of noncompliance and event rates between time intervals are also considered. The approach that models the noncompliance adjustment on the basis of survival functions is conservative and hence requires larger sample size. The model to be selected for noncompliance adjustment depends upon available estimates of noncompliance and event rate patterns.


2021 ◽  
Author(s):  
L. Howells ◽  
S. Gran ◽  
J. R. Chalmers ◽  
B. Stuart ◽  
M. Santer ◽  
...  

2017 ◽  
Vol 23 (5) ◽  
pp. 644-646 ◽  
Author(s):  
Maria Pia Sormani

The calculation of the sample size needed for a clinical study is the challenge most frequently put to statisticians, and it is one of the most relevant issues in the study design. The correct size of the study sample optimizes the number of patients needed to get the result, that is, to detect the minimum treatment effect that is clinically relevant. Minimizing the sample size of a study has the advantage of reducing costs, enhancing feasibility, and also has ethical implications. In this brief report, I will explore the main concepts on which the sample size calculation is based.


1994 ◽  
Vol 13 (8) ◽  
pp. 859-870 ◽  
Author(s):  
Robert P. McMahon ◽  
Michael Proschan ◽  
Nancy L. Geller ◽  
Peter H. Stone ◽  
George Sopko

2014 ◽  
Vol 56 (4) ◽  
pp. 614-630 ◽  
Author(s):  
Alexandra C. Graf ◽  
Peter Bauer ◽  
Ekkehard Glimm ◽  
Franz Koenig

Stroke ◽  
2009 ◽  
Vol 40 (7) ◽  
pp. 2362-2367 ◽  
Author(s):  
Kurt T. Kreiter ◽  
Stephan A. Mayer ◽  
George Howard ◽  
Volker Knappertz ◽  
Don Ilodigwe ◽  
...  

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