What does "the two arms" mean here? Two groups?

[NewHopeR]

Context:

Patients and Methods
Eligible patients were randomly assigned 2:1 to receive vandetanib 300 mg/d or placebo until disease progression or unacceptable toxicity. The primary objective was to compare the outcomes between the two arms with respect to overall survival.

 

[bhaisahab]

Context:

Patients and Methods
Eligible patients were randomly assigned 2:1 to receive vandetanib 300 mg/d or placebo until disease progression or unacceptable toxicity. The primary objective was to compare the outcomes between the two arms with respect to overall survival.

It would seem to mean that.

 

[NewHopeR]

It would seem to mean that.

Thank you.

And then the author also used "the cohorts" to refer to "the two groups"?

Results Overall, 924 patients received vandetanib (n = 617) or placebo (n = 307). No significant increase in overall survival was detected in the vandetanib cohort compared with placebo (hazard ratio = 0.95; 95.2% CI, 0.81 to 1.11; P = .527); median overall survival was 8.5 months versus 7.8 months for vandetanib and placebo patients, respectively. Statistically significant advantages favoring vandetanib were observed for progression-free survival (hazard ratio = 0.63; P < .001) and objective response rate (2.6% v 0.7%; P = .028). Postprogression therapy was balanced across the cohorts in both number and type. Adverse events were generally consistent with previous NSCLC studies of vandetanib 300 mg; common events occurring with a greater frequency in the vandetanib arm versus placebo included diarrhea (46% v 11%), rash (42% v 11%), and hypertension (26% v 3%).

 

[BobK]

Thank you.

And then the author also used "the cohorts" to refer to "the two groups"?

:up: That's the more common word, in statistical texts. I wonder why they used 'arm' previously...:-?

b

 

[BobSmith]

I did not know this definition of cohort:

co·hort

noun \ˈkō-ˌhȯrt\

Definition of COHORT

1

d : a group of individuals having a statistical factor (as age or class membership) in common in a demographic study <a cohort of premedical students>
​

- Cohorts - Definition and More from the Free Merriam-Webster Dictionary