[R-meta] Correlation between two continuous outcome

Sat Apr 20 20:06:10 CEST 2024

Dear Reza,
Thanks for your response. I want to see the correlation between them pain and BDNF.

##For pain
pain <- escalc(measure = "SMD", n1i = nexp, m1i = Int_mean, sd1i = Int_sd, n2i = ncon, m2i = Con_mean, sd2i = Con_sd, data = dat_pain)

##ForBDNF
bdnf <- escalc(measure = "MD", n1i = nexp, m1i = Intmean, sd1i = Intsd, n2i = ncon, m2i = Conmean, sd2i = Consd, data = dat_bdnf)

Please find my dataset below.

study_label
nexp
ncon

Int_mean
Int_sd
Con_mean
Con_sd
BDNF
Intmean
Intsd
Conmean
Consd
Ali et al., 2022
32
16
PCP-intensity
-7.32
4.26
-3.87
6.12
ng/ml
0.89
18.98
0.94
19.19
Mustafaoglu et al., 2024
34
17
NPS(0-10)
-3.91
1.489
-1.91
1.56
ng/ml
-15.76
32.42
-10.99
27.43
Rustem et al., 2024
34
17
NPS(0-10)
-3.12
1.42
-2.19
1.51
ng/ml
-15.27
35.77
-3.77
31.46
Dall’Agnol et al., 2014
12
12
VAS(0-10)
-3.37
2.45
-1.54
2.63
ng/ml
38.07
21.39
25.68
10.69
de Paula et al., 2023
21
22
VAS(0-10)
-0.42
2.66
-1.45
2.45
ng/ml
-1.56
5.17
-1.23
3.97
Lao et al., 2023
22
21
VAS(0-10)
-1.09
2.44
-0.2
2.44
ng/ml
-1.32
6.22
-0.52
5.56
Graca-Tarragó et al., 2019
15
15
VAS(0-10)
-3.69
2.41
-3.15
2.14
ng/ml
-6.94
36.6
-1.42
32.29
Fatif et al., 2019
15
15
VAS(0-10)
-6.41
1.73
-4.22
2.31
ng/ml
-15.2
32.39
0.49
31.27
Medeiros et al., 2016
11
12
VAS(0-10)
-4.04
2.18
-4.26
2.52
ng/ml
3.23
16.75
2.23
13.1
Ahmed et al., 2016
12
11
VAS(0-10)
-5.29
2.19
-2.67
2.11
ng/ml
3.18
30.43
-7.27
37.32
Zhao et al., 2019
24
24
NRS(0-10)
-0.25
0.72
0.08
1.04
ng/mL
14.58
25.96
-7.86
26.06

Best regards,

Ishtiaq Ahmed

Ph.D. Researcher

[cid:8eceda28-6691-4c9e-9c96-da240542ee88]  [cid:b92c3a1f-82f6-4334-9244-4bbba41e5a4f]

Faculty of Physical Education and Physiotherapy

Department KIMA/KINE

Vrije Universiteit Brussels

Pleinlaan 2 - 1050 Brussel - www.vub.be<https://www.vub.be/>

Pain in Motion International Research Group – www.paininmotion.be<http://www.paininmotion.be/>

[cid:a2aa3461-f5a7-4e75-b521-5feb2a7c9ca2]
________________________________
From: Reza Norouzian <rnorouzian using gmail.com>
Sent: Saturday, 20 April 2024 16:20
To: R Special Interest Group for Meta-Analysis <r-sig-meta-analysis using r-project.org>
Cc: Ishtiaq Ahmed <Ishtiaq.Ahmed using vub.be>
Subject: Re: [R-meta] Correlation between two continuous outcome

Hi Ishtiaque,

Can you possibly share a little more specifics about the dataset you are working with? For example, how many studies do you have? How many of them simultaneously studied the effect of X intervention on both pain intensity and the several pain biomarkers of interest? Indeed, how many pain biomarkers do you have and are there any that is/are not the focus of your study?

Also, if you could share the structure of your data for a couple of studies in a concise manner (ex. below), our list members could likely better assist you.

Reza

study  SMD V   intensity   PDNF    . . . last_pain_biomarkers
1     .6  .1   number      number        number
1      1  .2   number      number        number
1     .9  .3   number      number        number
2     .7  .2   number      number        number
2     .8  .4   number      number        number

On Fri, Apr 19, 2024 at 10:30 AM Ishtiaq Ahmed via R-sig-meta-analysis <r-sig-meta-analysis using r-project.org<mailto:r-sig-meta-analysis using r-project.org>> wrote:
Hi everyone,
I hope everyone is doing well. My understanding of correlation meta-analysis is limited, and I'm seeking to enhance it. Currently, I'm conducting a meta-analysis to assess the effect of X intervention on both pain intensity and several pain biomarkers (such as BDNF, beta-endorphin, etc.) as compared with the control. I'm particularly interested in exploring the correlation between pain intensity and BDNF levels, both of which are continuous variables.
I used escalc() to calculate the standardized mean difference (SMD) for pain intensity, considering the varying measurement scales between the intervention and control groups. Additionally, I've also calculated the mean difference (MD) for BDNF levels using the differences between the intervention and control groups.
My question is whether it's possible to convert SMD/MD to correlation coefficient (r) to perform the correlation meta-analysis. Alternatively, are there other approaches to utilizing SMD and MD for this analysis? Additionally, some of the studies (though not all) have provided beta-values for the correlation between pain intensity and BDNF. Can I incorporate these beta-values into the meta-analysis?

I would greatly appreciate any suggestions or sources you can provide.

Best regards,

Ishtiaq Ahmed

Ph.D. Researcher

Vrije Universiteit Brussels

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