[R-meta] Fw: Question about the metafor package

[Safa Aouinti]

Dear all,
I would like to generate a meta-regression using the function rma (package metafor) with mods option and I have a question about how we can precise in mods the covariates in each group (TRT and control) ? 
This is an extract of my data 


|  
Study
  |  
N_TRT
  |  
N_Control
  |  
mean_TRT
  |  
SD_TRT
  |  
mean_Control
  |  
SD_Control
  |  
Age_TRT_mean
  |  
Age_TRT_SD
  |  
male_TRT_pc
  |  
Age_control_mean
  |  
Age_control_SD
  |  
male_control_pc
  |
|  
[Study1, 2008]
  |  
86
  |  
55
  |  
12.72
  |  
2.56
  |  
14.5
  |  
2.04
  |  
19.2
  |  
2.6
  |  
57
  |  
21.2
  |  
6.1
  |  
60
  |
|  
[Study2, 2013]
  |  
43
  |  
86
  |  
13.4
  |  
0.6
  |  
15.3
  |  
0.3
  |  
23.5
  |  
3.8
  |  
27.9
  |  
29.2
  |  
6.7
  |  
46.5
  |
|  
[Study3, 2018]
  |  
12
  |  
23
  |  
17.58
  |  
2.67
  |  
18.48
  |  
1.34
  |  
24.5
  |  
3.1
  |  
100
  |  
27.04
  |  
2.91
  |  
100
  |
|  
[Study4, 2015]
  |  
675
  |  
264
  |  
31.68
  |  
5.3
  |  
33.95
  |  
4.48
  |  
18.49
  |  
4.25
  |  
57.6
  |  
19.77
  |  
4.72
  |  
51.5
  |

........
my code is:
dat1 <- escalc(measure="SMD", m1i= mean_TRT, sd1i= SD_TRT, n1i=N_TRT,               m2i=mean_Control, sd2i=SD_Control, n2i=N_Control, data=metadata, digits = 2)
res <- metafor::rma(data = dat1,                    yi = yi, # effect size                    vi = vi,                     method = "DL",mods=~............,                    slab = Study)

I would like to precise in the meta-regression (in mods option) the age in the group TRT (Age_TRT), the age in the group control (Age_control_pc), the percentage of males in the group TRT (male_TRT_pc) and the percentage of males in the group control (male_control_pc). Is-it possible ? or it should be treated differently ?
The purpose of this meta-regression is to compare the mean difference of a medical test between two groups (treatment 'TRT' and control) and see if the age and the gender (male percentage) influence the results.
Thank you in advance for your help !
Best regards.--
Safa Aouinti Ph.D. in applied Mathematics and Statistics


  
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