[R-meta] Question metafor network meta-analysis with multiple time points

[Gerjon Hannink]

Dear Wolfgang,

I'm using a contrast-based approach. My data structure looks like (modified
from 'dat.hasselblad1998'):

        authors year                               trt time   TE seTE
    Reid et al. 1974     no_contact vs. ind_counseling    1  ...  ...
    Reid et al. 1974     no_contact vs. ind_counseling    2  ...  ...
    Reid et al. 1974     no_contact vs. ind_counseling    3  ...  ...
Cottraux et al. 1983     no_contact vs. ind_counseling    1  ...  ...
Cottraux et al. 1983     no_contact vs. ind_counseling    2  ...  ...
Cottraux et al. 1983 ind_counseling vs. grp_counseling    1  ...  ...
Cottraux et al. 1983 ind_counseling vs. grp_counseling    2  ...  ...
Cottraux et al. 1983     no_contact vs. grp_counseling    1  ...  ...
Cottraux et al. 1983     no_contact vs. grp_counseling    2  ...  ...
                 ...                               ...  ...  ...  ...

Thanks & best regards,
Gerjon




On Thu, Nov 21, 2024 at 1:05 PM Viechtbauer, Wolfgang (NP) <
wolfgang.viechtbauer using maastrichtuniversity.nl> wrote:

> Dear Gerjon,
>
> Can you show what your data structure looks like? You don't have to show
> the actual data, but it would help to know how the data are structured.
> Like:
>
> Study Time Trt
> --------------
> ?     ?    ?
> ...
>
> And are you using a contrast- or an arm-based approach for conducting your
> network meta-analysis?
>
> Best,
> Wolfgang
>
> > -----Original Message-----
> > From: R-sig-meta-analysis <r-sig-meta-analysis-bounces using r-project.org>
> On Behalf
> > Of Gerjon Hannink via R-sig-meta-analysis
> > Sent: Wednesday, November 20, 2024 16:25
> > To: r-sig-meta-analysis using r-project.org
> > Cc: Gerjon Hannink <gerjonhannink using gmail.com>
> > Subject: [R-meta] Question metafor network meta-analysis with multiple
> time
> > points
> >
> > Hi all,
> >
> > I have a `metafor` question, and hope you can help me out. I was
> > thinking of (and struggling with) how I would do a network
> > meta-analysis with studies with measurements at multiple time points
> > using `rma.mv` from the `metafor` -package. Would that be possible?
> >
> > In many presentations (e.g. provided on
> > https://www.wvbauer.com/doku.php/presentations) I find 'multiple time
> > points' and 'network meta-analysis'. In these examples, the following
> > is used, e.g.,
> >
> > `res <- rma.mv(yi, V, mods = ~ factor(time) - 1, data = dat.long,
> > random = ~ time | study, struct = "HAR")` and
> > `res <- rma.mv(yi, vi, mods = ~ trt, data = dat, random = ~ 1 |
> > study/trt)`, respectively.
> >
> > Would it be as simple as just combining the two? I guess it is not
> > that simple...
> >
> > I played a bit using something like:
> >
> > rma.mv(yi, V, mods = ~ factor(time) * trt , data = dat.long, random =
> > ~ time | study/trt)
> >
> > But this returned an error message 'Cannot use '~ inner |
> > outer1/outer2' type terms in the 'random' argument'.
> > I guess I would also need to modify V a bit to take all necessary
> > variances/covariance into account...
> > And what about `struct`?
> >
> > Thanks for your help & looking forward to hearing your thoughts!
> >
> > Best regards,
> > Gerjon
>

	[[alternative HTML version deleted]]