-------------------------------------------------------------------------------------------------------------------
name:
log: C:\git\artbin\examples\artbin_examples.log
log type: text
opened on: 23 May 2023, 17:06:31
.
.
. which artbin
c:\ado\personal\a\artbin.ado
*!version 2.0.2 EMZ 23may2023
. which art2bin
c:\ado\personal\a\art2bin.ado
*!version 1.01 09june2022
.
.
.
. /***
> \subsection{Binary outcome and comparison with published sample size}
> We reproduce the sample size calculation in \citet{Pocock83} for a 2-arm superiority trial comparing the efficacy
> of therapeutic doses of anturan in patients after a myocardial infarction with the placebo standard treatment.
> The primary outcome was death from any cause within one year of first treatment. The control (placebo) arm was e
> xpected to have a 10\% probability of death within one year and the anturan treatment arm a 5\% probability, with
> the trial powered at 90\%. The patient outcome was binary; either failure (death in a year) or success (surviva
> l). The published sample size was 578 patients per arm (1156 patients in total).
> In the below \texttt{artbin} example we do not specify in the syntax whether the outcome is favourable or unfavou
> rable, rather we let the program infer it. The aim of a clinical trial is always to improve patient outcome, the
> refore as the experimental arm anticipated probability ($\pi_2 = 0.05$) is $less$ $than$ the control arm anticipa
> ted probability ($\pi_1 = 0.1$) then the outcome is inferred to be unfavourable (i.e. the trial is aiming to $red
> uce$ the probability of the event occurring, in this case, death).
> ***/
.
.
. artbin, pr(0.1 0.05) alpha(0.05) power(0.9) wald
ART - ANALYSIS OF RESOURCES FOR TRIALS (binary version 2.0.2 23may2023)
------------------------------------------------------------------------------
A sample size program by Abdel Babiker, Patrick Royston, Friederike Barthel,
Ella Marley-Zagar and Ian White
MRC Clinical Trials Unit at UCL, London WC1V 6LJ, UK.
------------------------------------------------------------------------------
Type of trial superiority
Number of groups 2
Favourable/unfavourable outcome unfavourable
Inferred by the program
Allocation ratio equal group sizes
Statistical test assumed unconditional comparison of 2
binomial proportions
using the wald test
Local or distant distant
Continuity correction no
Anticipated event probabilities 0.100 0.050
Alpha 0.050 (two-sided)
(taken as .025 one-sided)
Power (designed) 0.900
Total sample size (calculated) 1156
Sample size per group (calculated) 578 578
Expected total number of events 86.70
------------------------------------------------------------------------------
. local n=r(n)
.
.
. /***
> The \texttt{artbin} output table shows the trial set-up information including the study design, statistical tests
> and methods used. The hypothesis tests are shown with the calculated sample size and events based on the select
> ed power.
> A total sample size of 1156 participants is required, as per the published sample size given by Pocock.
> The same result is achieved by the code \texttt{artbin, pr(0.9 0.95) alpha(0.05) power(0.9) wald} assuming a favo
> urable outcome (survival) instead.
> The Wald test is used instead of the default score test as Pocock used the sample estimate in the method of estim
> ating the variance of the difference in proportions under the null hypothesis $H_{0}$.
>
> \subsection{Binary outcome and comparison with \texttt{power}}
> We compare the output of \texttt{artbin} to Stata's \texttt{power} command, which like \texttt{artbin} uses the s
> core test as the default.
> ***/
.
.
. power twoproportions 0.1 0.05, alpha(0.05) power(0.9)
Performing iteration ...
Estimated sample sizes for a two-sample proportions test
Pearson's chi-squared test
Ho: p2 = p1 versus Ha: p2 != p1
Study parameters:
alpha = 0.0500
power = 0.9000
delta = -0.0500 (difference)
p1 = 0.1000
p2 = 0.0500
Estimated sample sizes:
N = 1,164
N per group = 582
. local npower=r(N)
.
. artbin, pr(0.1 0.05) alpha(0.05) power(0.9)
ART - ANALYSIS OF RESOURCES FOR TRIALS (binary version 2.0.2 23may2023)
------------------------------------------------------------------------------
A sample size program by Abdel Babiker, Patrick Royston, Friederike Barthel,
Ella Marley-Zagar and Ian White
MRC Clinical Trials Unit at UCL, London WC1V 6LJ, UK.
------------------------------------------------------------------------------
Type of trial superiority
Number of groups 2
Favourable/unfavourable outcome unfavourable
Inferred by the program
Allocation ratio equal group sizes
Statistical test assumed unconditional comparison of 2
binomial proportions
using the score test
Local or distant distant
Continuity correction no
Anticipated event probabilities 0.100 0.050
Alpha 0.050 (two-sided)
(taken as .025 one-sided)
Power (designed) 0.900
Total sample size (calculated) 1164
Sample size per group (calculated) 582 582
Expected total number of events 87.30
------------------------------------------------------------------------------
. local nartbin=r(n)
.
.
. /***
> Both give a total sample size of `nartbin'.
>
> \subsection{One-sided non-inferiority trial}
> Next we show a one-sided non-inferiority trial with the 'onesided' option. We assume a 90\% probability of survi
> val in both the control and treatment arms, with the treatment arm being no more than 5\% less effective than the
> control.
> ***/
.
. artbin, pr(0.9 0.9) margin(-0.05) onesided
ART - ANALYSIS OF RESOURCES FOR TRIALS (binary version 2.0.2 23may2023)
------------------------------------------------------------------------------
A sample size program by Abdel Babiker, Patrick Royston, Friederike Barthel,
Ella Marley-Zagar and Ian White
MRC Clinical Trials Unit at UCL, London WC1V 6LJ, UK.
------------------------------------------------------------------------------
Type of trial non-inferiority
Number of groups 2
Favourable/unfavourable outcome favourable
Inferred by the program
Allocation ratio equal group sizes
Statistical test assumed unconditional comparison of 2
binomial proportions
using the score test
Local or distant distant
Continuity correction no
Null hypothesis H0: H0: pi2 - pi1 <= -.05
Alternative hypothesis H1: H1: pi2 - pi1 > -.05
Anticipated event probabilities 0.900 0.900
Alpha 0.050 (one-sided)
Power (designed) 0.800
Total sample size (calculated) 914
Sample size per group (calculated) 457 457
Expected total number of events 822.60
------------------------------------------------------------------------------
.
.
. /***
>
> A sample size of 457 is required in each group.
>
> \subsection{Superiority trial with multiple arms}
> Next we demonstrate a superiority trial with more than 2 arms. Instead of comparing each of the treatment arms t
> o the control group, \texttt{artbin} uses a global test to assess if there is $any$ difference among the groups.
> ***/
.
.
. artbin, pr(0.1 0.2 0.3 0.4) alpha(0.1) power(0.9)
ART - ANALYSIS OF RESOURCES FOR TRIALS (binary version 2.0.2 23may2023)
------------------------------------------------------------------------------
A sample size program by Abdel Babiker, Patrick Royston, Friederike Barthel,
Ella Marley-Zagar and Ian White
MRC Clinical Trials Unit at UCL, London WC1V 6LJ, UK.
------------------------------------------------------------------------------
Type of trial superiority
Number of groups 4
Favourable/unfavourable outcome not determined
Allocation ratio equal group sizes
Statistical test assumed unconditional comparison of 4
binomial proportions
using the score test
Local or distant distant
Continuity correction no
Anticipated event probabilities 0.100 0.200 0.300 0.400
Alpha 0.100 (two-sided)
Power (designed) 0.900
Total sample size (calculated) 176
Sample size per group (calculated) 44 44 44 44
Expected total number of events 44.00
------------------------------------------------------------------------------
.
.
. /***
>
> A sample size of 44 is required in each of the four groups.
>
> \subsection{Complex non-inferiority trial in a real-life setting} \label{sec:complexNIexample}
> Finally, we demonstrate a more complex non-inferiority design from the STREAM trial. The need for the STREAM tri
> al arose from the increase of multi-drug resistant strains of Tuberculosis, especially in countries without robus
> t health care systems unable to administer and follow up treatment over long periods of time. The STREAM trial e
> valuated a shorter more intensive treatment for multi-drug resistant Tuberculosis compared to the lengthier treat
> ment recommended by the World Health Organization.
> The trial used an expected 0.7 probability on control ($\pi_1$) and 0.75 on treatment ($\pi_2$), hence it was ass
> umed that 70\% in the long-regimen group and 75\% of the participants in the short-regimen group would attain a f
> avourable outcome. A favourable outcome was defined as cultures negative for $Mycobacterium$ $tuberculosis$ at 1
> 32 weeks and at a previous occasion, with no intervening positive culture or previous unfavourable outcome \citep
> {Nunn2019}. A 10 percentage-point non-inferiority margin was considered to be an acceptable difference in effica
> cy, given the shorter treatment duration ($m =$ -0.1 defined as $\pi_2$-$\pi_1$), with twice as many patients in
> treatment compared to control. The \texttt{wald} test was applied as it is often used in non-inferiority trials.
>
> ***/
.
.
. artbin, pr(0.7 0.75) margin(-0.1) power(0.8) ar(1 2) wald ltfu(0.2)
ART - ANALYSIS OF RESOURCES FOR TRIALS (binary version 2.0.2 23may2023)
------------------------------------------------------------------------------
A sample size program by Abdel Babiker, Patrick Royston, Friederike Barthel,
Ella Marley-Zagar and Ian White
MRC Clinical Trials Unit at UCL, London WC1V 6LJ, UK.
------------------------------------------------------------------------------
Type of trial non-inferiority
Number of groups 2
Favourable/unfavourable outcome favourable
Inferred by the program
Allocation ratio 1:2
Statistical test assumed unconditional comparison of 2
binomial proportions
using the wald test
Local or distant distant
Continuity correction no
Null hypothesis H0: H0: pi2 - pi1 <= -.1
Alternative hypothesis H1: H1: pi2 - pi1 > -.1
Anticipated event probabilities 0.700 0.750
Alpha 0.050 (two-sided)
(taken as .025 one-sided)
Power (designed) 0.800
Loss to follow up assumed: 20 %
Total sample size (calculated) 399
Sample size per group (calculated) 133 266
Expected total number of events 292.60
------------------------------------------------------------------------------
. local n=r(n)
.
. /***
> The non-inferiority trial required a total sample size of 399 (133 in control, 266 in intervention), assuming 20\
> % of patients were not accessible in primary analysis. When the STREAM trial concluded, it estimated that a shor
> ter more intensive treatment for multi-drug resistant Tuberculosis was only 1\% less effective than the lengthier
> treatment recommended by the World Health Organization, and demonstrated significant evidence of non-inferiority
> .
>
>
> ***/
.
. log close
name:
log: C:\git\artbin\examples\artbin_examples.log
log type: text
closed on: 23 May 2023, 17:06:32
-------------------------------------------------------------------------------------------------------------------