[R-meta] Meta-analysis of proportion differences (certain cells frequency)

[Jakub Ruszkowski]

Dear Wolfgang, 

thank you for your answer! Yes, I am aware of the compositional character of
the data (I wish all authors of primary studies were also) and the huge
limitations of any attempts to meta-analyze them. Unfortunately, I do not know
any well-explained method to meta-analyze simultaneously all components of the
composition properly, that is why I thought about simplification the issue to
the analysis of differences of main cell types of interest. 

Yeah, the authors usually report the mean and SD of the proportions. I forgot
that sample means even from beta (/Dirichlet) distributions follow the normal
distribution! Thank you a lot for clarifying that it is ok to use methods for
mean differences. In case some studies would report cell counts, would you
rather analyze them together with studies reporting only mean+SD [%] (using
SMD) or treat them separately? 

Best wishes
Jakub 

W dniu 2024-03-15 14:44, Viechtbauer, Wolfgang (NP) napisał(a): 

> Dear Jakub,
> 
> Proportions like you are describing can be thought of as so-called 'compositional data' (i.e., data that describe to what extent some whole is composed of various subcomponents):
> 
> https://en.wikipedia.org/wiki/Compositional_data [2]For example, one might know that in a given person, 52% of their white blood cells are eutrophils, 36% are lymphocytes, 7% are monocytes, and the remaining 5% are other types. But without an actual count, these cannot be treated as binomial/multinomial counts and are just percentages (or proportions) of the whole.
> 
> Compositional data analysis is its own subfield in statistics, but whether the methods described there are relevant in the present context is not clear to me.
> 
> Since you mentioned the beta distribution: Yes, one could assume that a percentage/proportion like in the case above (i.e., a proportion of 0.36 of the white blood cells are lymphocytes) is beta distributed. But note that this is a proportion for a single individual. I would assume that there is such a proportion for multiple individuals within a group (e.g., patients). Then what is it that study authors would report? I would assume that they report the mean proportion (with hopefully also the SD of the individual proportions). If so, then one could basically just use methods for meta-analyzing means and mean differences.
> 
> Best,
> Wolfgang
> 
>> -----Original Message----- From: R-sig-meta-analysis <r-sig-meta-analysis-bounces using r-project.org> On Behalf Of Jakub Ruszkowski via R-sig-meta-analysis Sent: Monday, March 11, 2024 17:43 To: R sig meta analysis <r-sig-meta-analysis using r-project.org> Cc: Jakub Ruszkowski <jakub.ruszkowski using gumed.edu.pl> Subject: [R-meta] Meta-analysis of proportion differences (certain cells frequency) Dear All, I am looking for guidance on performing a meta-analysis of the proportions difference using R. Specifically, I am interested in analyzing the difference in certain cell frequencies: for example, the difference in lymphocyte% among all white blood cells between patients and healthy individuals, without having information about the total white blood cell count. I would appreciate it if anyone could provide insights or point me in the right direction regarding the appropriate R packages and methods for conducting such a meta-analysis. On a related note, I came across information suggesting that the
difference between two beta distributions (likely representing fraction values) does not follow a normal distribution: https://blogs.sas.com/content/iml/2023/03/01/distribution-difference-beta.html [1]. Because of that, I am afraid that I cannot use rma function. Thank you in advance for your time and support. Best regards, Jakub Ruszkowski Department of Nephrology, Transplantology and Internal Medicine Medical University of Gdańsk
 

Links:
------
[1]
https://blogs.sas.com/content/iml/2023/03/01/distribution-difference-beta.html
[2] https://en.wikipedia.org/wiki/Compositional_data

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