Difference between itt and safety populations

[samchat]

Hello, I am a newbie here and needed your help. Can anyone please let me know the difference between "intent to treat" (itt) and safety populations?

I was in the process of flagging some data which I was working on, and got stuck not knowing the difference.

Thanks for your help.

-Sam

[michael90]

it is not defined somewhere? i think the itt may be larger, the safety are those people from which safety measurements are known like vital signs etc, thus actually treated. itt may contain drop-outs, or may be smaller than safety when it is decided that some primary objectives are relevant for a subgroup.

[RW9]

Hi,

This is not really a SAS specific discussion.  It should be defined in your specs/protocol somewhere what these are.  As for actual definitions - Wikipedia:

http://en.wikipedia.org/wiki/Intention_to_treat_analysis

So ITT is those randomized based on randomized treatment not what they were actually given.

Safety is all randomized with any treatment.

Again, might be slightly different depending on your specs.

[Jagadishkatam]

to add some more definition

ITT:

Includes all randomized patients in the groups to which they were randomly assigned, regardless of their adherence with the entry criteria, regardless of the treatment they actually received,

and regardless of subsequent withdrawal from treatment or deviation from the protocol. it simply means that any subject who is randomized is considered in ITT, even if the subject is not 100% compliant with the study, withdrew from study. So if the subject is once randomized is still considered for analysis.

Safety:

subjects randomized and who took atleast one dose of study medication are considered as safety population.

Thanks,

Jag

[samchat]

Thank you Jag!!

[H]

See:

Detry & Roger. The Intention-to-Treat Principle. JAMA. 312(1);2014:85.

[probert7]

A references are papesr by John Lachin "Statistical Considerations in the Intent to Treat Principle"

21 Controlld Clinical Trials 167 (2000); and Lewis and Machin "Intention to treat -- who should use

ITT?" 68 Br. J. Cancer 647 (1993). Pure ITT is irrespective of events occurring post-randomization

and classifies subjects wtih respect to the randomized treatment assignment. ICH E9 is also pertinent.

Note that ICH E9 refers to the "Full Analysis Set", which appears to me to be something less than pure

ITT -- calling for the analysis set to be as close as possible to the "ITT ideal".  And in practice, sometimes

one will see trials using MITT (modified ITT) which requires the receipt of at least one dose of a study

medication.   

[VinayVemula]

ITT Population: The ITT (Intent-to-Treat) population includes all subjects who are randomized in the study, regardless of whether they received the treatment or adhered to the study protocol. For example, if a study randomizes 20 subjects, with 15 receiving the treatment, 3 not receiving the treatment, and 2 not assigned treatment, then:

• RANDFL: This includes all subjects who were randomized, so RANDFL="Y" for all 20 subjects.
• ITTFL: This includes all randomized subjects, whether or not they received the treatment. Therefore, ITTFL="Y" for the 18 subjects who were either treated or not treated (excluding the 2 not assigned treatment).
• SAFFL: This includes only those subjects who received at least one dose of the treatment. Therefore, SAFFL="Y" for the 15 subjects who were treated.

I hope this clarifies the definitions and examples for you.

Thanks,

VV

[prabhakar_reddy]

ITTFL:  Intent to treat population flag,

                 Subject randomized and whether actively participated or not in complete study. 

SAFFL:  Safety population flag,

                  Subject randomized and received at least one dose of study medication.

[VinayVemula]

ITT Population: The ITT (Intent-to-Treat) population includes all subjects who are randomized in the study, regardless of whether they received the treatment or adhered to the study protocol. For example, if a study randomizes 20 subjects, with 15 receiving the treatment, 3 not receiving the treatment, and 2 not assigned treatment, then:

• RANDFL: This includes all subjects who were randomized, so RANDFL="Y" for all 20 subjects.
• ITTFL: This includes all randomized subjects, whether or not they received the treatment. Therefore, ITTFL="Y" for the 18 subjects who were either treated or not treated (excluding the 2 not assigned treatment).
• SAFFL: This includes only those subjects who received at least one dose of the treatment. Therefore, SAFFL="Y" for the 15 subjects who were treated.

I hope this clarifies the definitions and examples for you.

[yesu]

HI

Randmize means assign to trt groups ,Here 20 subjects are randmized in this again 3 are not assign to trt How?