Title: Correlation between the geographical origin of Helicobacter pylori homB-positive strains
and their clinical outcomes: a systematic review and meta-analysis
Version: 1 Date: 08 Feb 2021
Reviewer's report:
Meta-analysis enable us to assimilate data from a variety of sources and derive variability among
effect sizes, moderator variables and the mean and variance of underlying population effect from
the previous study results. There are six processes for conducting a meta-analysis study. The
first process of meta-analysis is doing a literature search. The authors performed a literature
search by using global databases such as Scopus, Web of Science, and PubMed to collect all
the studies relevant to the study’s purpose. Then the decision on some inclusion criteria and
applying them should be done. In the study, inclusion and exclusion criterias are defined. 138
related articles were collected and 126 articles were deleted according to inclusion criteria. In
addition, calculating effect sizes for each included study; doing the basic meta-analysis; doing
more advanced analysis like publication bias analysis and exploring moderator variables are the
next steps respectively. Random-effects model, and fixed-effects model are both used. The bias
is measured by using funnel plot and Egger’s test which  predicts discordance of results when
meta-analyses are compared with single large trials. The last process of meta-analysis is the
writing part of the overall results of the meta-analysis.
My concerns are listed below:
1- The statistical results are presented in the text. However I could not find average effect size
score. Is it reported? If not, why?
2- Studies have more balance under a random effects model. Under the fixed effects model,
larger studies share most of the total weight. Under the random effects model, extreme studies
is related to their sizes. If they are large, they lose their effects, whereas if they are small, they
gain influence. I could not find effect size and overall effect size based on random and fixed
effects model scores in the forest plots.
3- For statistical reporting, radial plot is also a good option to represent aggregate data.
4- Heterogeneity test results and publication bias are provided in the study. Did authors use
moderator analysis? If not, why? Moderating effects should be provided to represent information
about statistical difference in effect size.
Title: Correlation between the geographical origin of Helicobacter pylori homB-positive strains
and their clinical outcomes: a systematic review and meta-analysis
Version: 1 Date: 08 Feb 2021
Reviewer's report:
Meta-analysis enable us to assimilate data from a variety of sources and derive variability among
effect sizes, moderator variables and the mean and variance of underlying population effect from
the previous study results. There are six processes for conducting a meta-analysis study. The
first process of meta-analysis is doing a literature search. The authors performed a literature
search by using global databases such as Scopus, Web of Science, and PubMed to collect all
the studies relevant to the study’s purpose. Then the decision on some inclusion criteria and
applying them should be done. In the study, inclusion and exclusion criterias are defined. 138
related articles were collected and 126 articles were deleted according to inclusion criteria. In
addition, calculating effect sizes for each included study; doing the basic meta-analysis; doing
more advanced analysis like publication bias analysis and exploring moderator variables are the
next steps respectively. Random-effects model, and fixed-effects model are both used. The bias
is measured by using funnel plot and Egger’s test which  predicts discordance of results when
meta-analyses are compared with single large trials. The last process of meta-analysis is the
writing part of the overall results of the meta-analysis.
My concerns are listed below:
1- The statistical results are presented in the text. However I could not find average effect size
score. Is it reported? If not, why?
2- Studies have more balance under a random effects model. Under the fixed effects model,
larger studies share most of the total weight. Under the random effects model, extreme studies
is related to their sizes. If they are large, they lose their effects, whereas if they are small, they
gain influence. I could not find effect size and overall effect size based on random and fixed
effects model scores in the forest plots.
3- For statistical reporting, radial plot is also a good option to represent aggregate data.
4- Heterogeneity test results and publication bias are provided in the study. Did authors use
moderator analysis? If not, why? Moderating effects should be provided to represent information
about statistical difference in effect size.
Please review this paper.
user
Title: Correlation between the geographical origin of Helicobacter pylori homB-positive strains
and their clinical outcomes: a systematic review and meta-analysis
Version: 1 Date: 08 Feb 2021
Reviewer's report:
Meta-analysis enable us to assimilate data from a variety of sources and derive variability among
effect sizes, moderator variables and the mean and variance of underlying population effect from
the previous study results. There are six processes for conducting a meta-analysis study. The
first process of meta-analysis is doing a literature search. The authors performed a literature
search by using global databases such as Scopus, Web of Science, and PubMed to collect all
the studies relevant to the study’s purpose. Then the decision on some inclusion criteria and
applying them should be done. In the study, inclusion and exclusion criterias are defined. 138
related articles were collected and 126 articles were deleted according to inclusion criteria. In
addition, calculating effect sizes for each included study; doing the basic meta-analysis; doing
more advanced analysis like publication bias analysis and exploring moderator variables are the
next steps respectively. Random-effects model, and fixed-effects model are both used. The bias
is measured by using funnel plot and Egger’s test which  predicts discordance of results when
meta-analyses are compared with single large trials. The last process of meta-analysis is the
writing part of the overall results of the meta-analysis.
My concerns are listed below:
1- The statistical results are presented in the text. However I could not find average effect size
score. Is it reported? If not, why?
2- Studies have more balance under a random effects model. Under the fixed effects model,
larger studies share most of the total weight. Under the random effects model, extreme studies
is related to their sizes. If they are large, they lose their effects, whereas if they are small, they
gain influence. I could not find effect size and overall effect size based on random and fixed
effects model scores in the forest plots.
3- For statistical reporting, radial plot is also a good option to represent aggregate data.
4- Heterogeneity test results and publication bias are provided in the study. Did authors use
moderator analysis? If not, why? Moderating effects should be provided to represent information
about statistical difference in effect size.
assistant