[R-meta] Forest plot and sub-networks in netmeta

Carla Gomez Creutzberg cgomezcre at gmail.com
Sun Jul 30 09:24:08 CEST 2017


Thanks a lot for this Gerta, it is most useful.
I had looked into the help and the documentation for netmeta but somehow
had not traced things back to the forest.meta help file. Guess I still have
bit of a way to learn with finding my way in R.
With best wishes,
Carla



On Fri, Jul 28, 2017 at 9:41 PM, Gerta Rücker <ruecker at imbi.uni-freiburg.de>
wrote:

> Dear Carla,
>
> The help file of the function forest.meta shows that the size of these
> boxes (there called squares) is proportional to the study weights (that may
> be inverse variances or may be determined otherwise, see argument
> weight.study) or (for netmeta) comparison weights. The width of these
> squares has no precise meaning, they can be interpreted only relatively to
> each other: A study / comparison with greater weight obtains a bigger
> square:
>
> weight.study: A character string indicating weighting used to determine
>           size of squares or diamonds (argument ‘type.study’) to plot
>           individual study results. One of missing, ‘"same"’,
>           ‘"fixed"’, or ‘"random"’, can be abbreviated. Plot symbols
>           have the same size for all studies or represent study weights
>           from fixed effect or random effects model.
>
> The colours of the square have merely practical meaning: The default
> colour of the square is gray, and the default colour of the confidence
> interval is black. If the study has large weight, the square may become
> wider than the confidence interval, and then the confidence interval (the
> "cross") becomes white. The square can also be so small that it looks like
> a vertical line.
>
> All these colours and properties may be changed by corresponding
> arguments, such as col.square, col.square.lines, squaresize. See
> help(forest.meta).
>
> Best,
> Gerta
>
>
> On 07/28/2017 05:08 AM, Carla Gomez Creutzberg wrote:
>
> Greetings everyone,
>
> I am conducting my first network meta-analysis and for that I have been
> using netmeta.
>
> I've read a bit on general and network meta-analysis I can;t seem to find
> any indication as to how to interpret the grey boxes or interval
> demarcations that show up in netmeta's forest plots?
>
> [image: Inline image 1]
>
> As shown in the image above (can also be found in the attachments as
> "forest.pl.jpeg"), these boxes appear to be plotted around some (or perhaps
> all) of the model estimates. In some cases they also appear to encompass an
> interval longer than the 95%CI intervals for the estimate which is then
> shown in white instead of black ink. I was wondering what type of interval
> was represented by these boxes and it was something that was estimated for
> all treatments or only some of them?
>
> In addition, for a couple of the meta-analyses I am doing I have found
> that the evidence networks are not well connected and end up as two
> separate sub-networks. I was wondering whether it was appropriate to
> conduct separate meta-analyses on the individual sub-networks or whether
> there was any other way to try and tackle the analysis in these cases?
>
> Thanks a lot for attention and any suggestions you can provide
>
> Carla
>
> On Fri, Jul 28, 2017 at 3:07 PM, Carla Gomez Creutzberg <
> cgomezcre at gmail.com> wrote:
>
>> Greetings everyone,
>>
>> I am conducting my first network meta-analysis and for that I have been
>> using netmeta.
>>
>> I've read a bit on general and network meta-analysis I can;t seem to find
>> any indication as to how to interpret the grey boxes or interval
>> demarcations that show up in netmeta's forest plots?
>>
>> [image: Inline image 2]
>>
>> As shown in the image above (can also be found in the attachments as
>> "forest.pl.jpeg"), these boxes appear to be plotted around some (or perhaps
>> all) of the model estimates. In some cases they also appear to encompass an
>> interval longer than the 95%CI intervals for the estimate which is then
>> shown in white instead of black ink. I was wondering what type of interval
>> was represented by these boxes and it was something that was estimated for
>> all treatments or only some of them?
>>
>> In addition, for a couple of the meta-analyses I am doing I have found
>> that the evidence networks are not well connected and end up as two
>> separate sub-networks. I was wondering whether it was appropriate to
>> conduct separate meta-analyses on the individual sub-networks or whether
>> there was any other way to try and tackle the analysis in these cases?
>>
>> Thanks a lot for attention and any suggestions you can provide
>>
>> Carla
>>
>>
>
>
>
> --
> *Carla Gómez Creutzberg*
> PhD. Candidate - Tylianakis Lab
> <http://www.tylianakislab.org/the-group.html>
> University of Canterbury - *Te Whare Wānanga o Waitaha*
> Christchurch, New Zealand
> cgomezcre at gmail.com
>
>
> _______________________________________________
> R-sig-meta-analysis mailing listR-sig-meta-analysis at r-project.orghttps://stat.ethz.ch/mailman/listinfo/r-sig-meta-analysis
>
>
> --
>
> Dr. rer. nat. Gerta Rücker, Dipl.-Math.
>
> Medical Faculty and Medical Center - University of Freiburg
> Institute for Medical Biometry and Statistics
>
> Stefan-Meier-Strasse 26, D-79104 Freiburg, Germany
>
> Phone +49 (0)761 2036673 <+49%20761%202036673>
> Fax   +49 (0)761 2036680 <+49%20761%202036680>
>
> Mail  ruecker at imbi.uni-freiburg.de
> Web   www.imbi.uni-freiburg.de/biom/
>
>


-- 
*Carla Gómez Creutzberg*
PhD. Candidate - Tylianakis Lab
<http://www.tylianakislab.org/the-group.html>
University of Canterbury - *Te Whare Wānanga o Waitaha*
Christchurch, New Zealand <http://www.tylianakislab.org/the-group.html>
cgomezcre at gmail.com
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