[R-meta] Network meta-analysis: including a within-person (split-leg) study + pooling absolute vs relative changeNetwork meta-analysis: including a within-person (split-leg) study + pooling absolute vs relative change

[Jorge Teixeira]

Hi. I'm planning a small network meta-analysis and would value your input
on two design questions.


*Setup*

I have three parallel-group RCTs comparing treatments A, B and C (mean
value at post per arm):

*Tx A*

*Tx B*

*Tx C*

Study I

100

150

Study II

200

200

Study III



200

200


I would like to add a fourth study (Study IV). It is a within-person
design: each participant's legs were randomized to different treatments, so
comparisons are within-group rather than between-group. I have the
post-treatment means + SD for each condition.


*Question 1:* Can Study IV be meta-analyzed together with the three
parallel RCTs?

*Study*

*Obs*

*Tx A*

*Tx B*

*Tx C*

Study I

1

100

150

—

Study II

1

200

200

Study III

1

200

200

—

Study IV

1





180

Study IV

2



170





*Question 2 (bonus):* Can I pool absolute change (Δ) with relative change?

Thanks a lot for your help.

Best,

Jorge

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