Severe Sepsis: The Fragile Anatomy of Crude Mortality

2021 ◽  
Author(s):  
Nicole C Vissichelli ◽  
Adam P Sima ◽  
Richard P Wenzel
Keyword(s):  
Clinical Trials ◽  
Severe Sepsis ◽  
Sample Size ◽  
Study Design ◽  
Total Mortality ◽  
Attributable Mortality ◽  
Sufficient Power ◽  
Crude Mortality ◽  
Requirements Change ◽  
Design Estimate

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.

scholarly journals General Characteristics and Reasons for the Discontinuation of Drug Clinical Trials in Mainland China

2020 ◽  
Author(s):  
Ben-nian Huo ◽  
Mao-lin Ai ◽  
Yun-tao Jia ◽  
Yao LIU ◽  
Nan-ge Yin ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Sample Size ◽  
Study Design ◽  
Mainland China ◽  
Research Centre ◽  
Careful Study ◽  
Business Decisions ◽  
Negative Results ◽  
Study Type ◽  
Trial Discontinuation

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.

Planning the Size of Clinical Trials with Allowance for Patient Noncompliance

1990 ◽  
Vol 29 (03) ◽  
pp. 243-246 ◽  
Author(s):  
M. A. A. Moussa
Keyword(s):  
Clinical Trial ◽  
Clinical Trials ◽  
Sample Size ◽  
Event Rate ◽  
Survival Functions ◽  
Time Intervals ◽  
Patient Noncompliance ◽  
Event Rates ◽  
Larger Sample

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.

scholarly journals Do patient characteristics matter when calculating sample size for eczema clinical trials?

2021 ◽  
Author(s):  
L. Howells ◽  
S. Gran ◽  
J. R. Chalmers ◽  
B. Stuart ◽  
M. Santer ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Sample Size ◽  
Patient Characteristics

The most frequently asked question to a statistician: The sample size

2017 ◽  
Vol 23 (5) ◽  
pp. 644-646 ◽  
Author(s):  
Maria Pia Sormani
Keyword(s):  
Clinical Study ◽  
Sample Size ◽  
Study Design ◽  
Treatment Effect ◽  
Sample Size Calculation ◽  
Ethical Implications ◽  
Number Of Patients ◽  
Reducing Costs ◽  
Correct Size

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.

Sample size calculation for clinical trials in which entry criteria and outcomes are counts of events

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

scholarly journals Maximum type 1 error rate inflation in multiarmed clinical trials with adaptive interim sample size modifications

2014 ◽  
Vol 56 (4) ◽  
pp. 614-630 ◽  
Author(s):  
Alexandra C. Graf ◽  
Peter Bauer ◽  
Ekkehard Glimm ◽  
Franz Koenig
Keyword(s):  
Clinical Trials ◽  
Sample Size ◽  
Error Rate ◽  
Type 1 Error ◽  
Multiarmed Clinical Trials

scholarly journals Sample Size Estimates for Clinical Trials of Vasospasm in Subarachnoid Hemorrhage

Stroke ◽  
2009 ◽  
Vol 40 (7) ◽  
pp. 2362-2367 ◽  
Author(s):  
Kurt T. Kreiter ◽  
Stephan A. Mayer ◽  
George Howard ◽  
Volker Knappertz ◽  
Don Ilodigwe ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Subarachnoid Hemorrhage ◽  
Sample Size ◽  
Size Estimates
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