4
$\begingroup$

I am currently conducting a meta-analysis in which I need to use a mixed treatment comparison method. As I understand it, this method works in the following way:

Say you have a group of studies that make the following set of treatment comparisons:

  • Intervention 1
  • Intervention 2
  • Intervention 3
  • Control

You are interested in all possible comparisons between these treatments. So, not only are you interested in intervention 1 versus control, intervention 2 versus control, and intervention 3 versus control, but also intervention 1 versus intervention 2, intervention 1 versus intervention 3, etc. The problem occurs in that not all of the studies in your meta analysis include each intervention type. So, while study 1 may have tested intervention 1, intervention 2, and a control group, study 2 tested intervention 2 and intervention 3 versus a control group. And so on. Mixed treatment comparisons (Caldwell, Ades, & Higgins, 2005; Lu & Ades, 2004; Mills et al., 2011) arose as a way of using the indirect information from your sample of studies to estimate the magnitude of the missing comparisons.

For my study, I am interested in how several different moderators affect the magnitude of the various treatment comparisons. I stumbled across a paper (Nixon, Bansback, & Brennan, 2007) that combines the mixed treatment comparison method with meta-regression. My problem is finding a good software implementation for this method (preferably an implementation in R, since I'm most familiar with R). As far as I can tell, the metafor package isn't able to handle mixed treatment comparisons. Does anybody know whether there's a package out there that's able to handle both mixed treatment comparisons and meta-regression?

|cite|improve this question
$\endgroup$
  • $\begingroup$ Please let me know, if you're you still interested in this topic - I wanted to share some information, but just paid attention to the dates... $\endgroup$ – Aleksandr Blekh Jan 10 '15 at 7:56
  • $\begingroup$ I am! I was editing the text of my old questions, and I discovered that doing these edits places the questions on the active list. However, this is definitely still a topic I'm interested in if you have some extra information. $\endgroup$ – Patrick S. Forscher Jan 10 '15 at 16:24
  • $\begingroup$ All right then - will post my answer soon. $\endgroup$ – Aleksandr Blekh Jan 11 '15 at 0:05
4
$\begingroup$

I cannot help you with an R implementation of the Nixon et al. paper. However, I remember a talk given by Ian White and colleagues on "Consistency and Inconsistency in Multiple Treatments Meta-Analysis: Models and Estimation". In this talk they presented a "multivariate random-effects meta-regression" which hopefully can be estimated using the mvmeta package. There also seems a paper available (haven't checked it yet): "Consistency and inconsistency in network meta-analysis: model estimation using multivariate meta-regression".

|cite|improve this answer
$\endgroup$
  • 1
    $\begingroup$ Bernd, thanks for your response. It looks like the mvmeta package is very new (published on CRAN on August 24!). The paper link references a Stata version of mvmeta, which seems to incorporate methods of dealing with mixed treatment comparisons. I'll have to see whether that functionality was also ported over to the R version of the package. $\endgroup$ – Patrick S. Forscher Aug 28 '12 at 18:12
  • $\begingroup$ It does indeed look like mvmeta has the appropriate functions for network meta-analysis (i.e., mixed treatment comparisons). Additionally, I have discovered several resources that might be useful for analysts wishing to use this method: the NICE Decision Support Unit website and the Multiple Treatments Meta-analysis website. $\endgroup$ – Patrick S. Forscher Aug 30 '12 at 15:20

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.