Reviewer's report
Title:Risk Score to Predict Gastrointestinal Bleeding after Acute Ischemic Stroke
Version:2Date:6 June 2014
Reviewer: Colin Crooks
Reviewer's report:
Major compulsory revisions are listed below:
The authors do not describe in the methods how long patients were followed up
for an occurrence of GIB. Were post discharge bleeds captured? What happens
if patients present to a different hospital with GIB after discharge? Table 1 and
the discussion suggest only in patient bleeds were included. If so this is
problematic as patients with longer periods in hospital have more time to have a
GIB event observed. Therefore predictors of longer inpatient stay will be
predictors of GIB in this study, even if not associated with GIB. This could explain
or least seriously confound the findings of this study.
For the same reasons Including length of hospital stay as a predictor of bleeding
is unhelpful as clearly the longer of hospital stay the longer the period in which to
capture a GIB and therefore it will itself become a 'risk factor'. Additionally the
length of hospital stay is not known at the start of the an admission which
contradicts the authors own statement that only risk factors known at the time of
the stroke were included.
There is a comment in the discussion that seems to suggest that the time of GIB
was not recorded? If this is the case how can the researchers know for certain
whether the GIB was before or after the stroke? Or whether the recording of risk
factors was definitely before the stroke and GIB (this is not fully described in the
methods but the discussion mentions information collected in the period after
admission was included in the study)?
Aren't the responses of the GCS score covered in the NIHSS, which also
includes an assessment of consciousness? So why include the GCS in addition
to the NIHSS?
Age was included as a linear variable in the model, yet the final score uses
categories. How were these categories selected? Was there any test done for a
departure from linear trend for age?
How reliable is the recording of the risk factors and outcomes within the
datasets? Has there been any validation of the variables used in the dataset?
What is the distribution of the score in the study population? Do most people
have a score of zero or is it evenly distributed?
What is the cross over between the CNSR and the CICAS? If these datasets
come from the same hospitals then the CICAs would not be an external
validation.
The detail for the comments above was lacking in the methods. I had to deduce it
from the discussion and tables but this should have been in the methods.
Level of interest: An article whose findings are important to those with closely
related research interests
Quality of written English: Acceptable
Statistical review: Yes, and I have assessed the statistics in my report.
Declaration of competing interests:
I declare that I have no competing interests
Reviewer's report
Title:Risk Score to Predict Gastrointestinal Bleeding after Acute Ischemic Stroke
Version:2Date:6 June 2014
Reviewer: Colin Crooks
Reviewer's report:
Major compulsory revisions are listed below:
The authors do not describe in the methods how long patients were followed up
for an occurrence of GIB. Were post discharge bleeds captured? What happens
if patients present to a different hospital with GIB after discharge? Table 1 and
the discussion suggest only in patient bleeds were included. If so this is
problematic as patients with longer periods in hospital have more time to have a
GIB event observed. Therefore predictors of longer inpatient stay will be
predictors of GIB in this study, even if not associated with GIB. This could explain
or least seriously confound the findings of this study.
For the same reasons Including length of hospital stay as a predictor of bleeding
is unhelpful as clearly the longer of hospital stay the longer the period in which to
capture a GIB and therefore it will itself become a 'risk factor'. Additionally the
length of hospital stay is not known at the start of the an admission which
contradicts the authors own statement that only risk factors known at the time of
the stroke were included.
There is a comment in the discussion that seems to suggest that the time of GIB
was not recorded? If this is the case how can the researchers know for certain
whether the GIB was before or after the stroke? Or whether the recording of risk
factors was definitely before the stroke and GIB (this is not fully described in the
methods but the discussion mentions information collected in the period after
admission was included in the study)?
Aren't the responses of the GCS score covered in the NIHSS, which also
includes an assessment of consciousness? So why include the GCS in addition
to the NIHSS?
Age was included as a linear variable in the model, yet the final score uses
categories. How were these categories selected? Was there any test done for a
departure from linear trend for age?
How reliable is the recording of the risk factors and outcomes within the
datasets? Has there been any validation of the variables used in the dataset?
What is the distribution of the score in the study population? Do most people
have a score of zero or is it evenly distributed?
What is the cross over between the CNSR and the CICAS? If these datasets
come from the same hospitals then the CICAs would not be an external
validation.
The detail for the comments above was lacking in the methods. I had to deduce it
from the discussion and tables but this should have been in the methods.
Level of interest: An article whose findings are important to those with closely
related research interests
Quality of written English: Acceptable
Statistical review: Yes, and I have assessed the statistics in my report.
Declaration of competing interests:
I declare that I have no competing interests
Please review this paper.
user
Reviewer's report
Title:Risk Score to Predict Gastrointestinal Bleeding after Acute Ischemic Stroke
Version:2Date:6 June 2014
Reviewer: Colin Crooks
Reviewer's report:
Major compulsory revisions are listed below:
The authors do not describe in the methods how long patients were followed up
for an occurrence of GIB. Were post discharge bleeds captured? What happens
if patients present to a different hospital with GIB after discharge? Table 1 and
the discussion suggest only in patient bleeds were included. If so this is
problematic as patients with longer periods in hospital have more time to have a
GIB event observed. Therefore predictors of longer inpatient stay will be
predictors of GIB in this study, even if not associated with GIB. This could explain
or least seriously confound the findings of this study.
For the same reasons Including length of hospital stay as a predictor of bleeding
is unhelpful as clearly the longer of hospital stay the longer the period in which to
capture a GIB and therefore it will itself become a 'risk factor'. Additionally the
length of hospital stay is not known at the start of the an admission which
contradicts the authors own statement that only risk factors known at the time of
the stroke were included.
There is a comment in the discussion that seems to suggest that the time of GIB
was not recorded? If this is the case how can the researchers know for certain
whether the GIB was before or after the stroke? Or whether the recording of risk
factors was definitely before the stroke and GIB (this is not fully described in the
methods but the discussion mentions information collected in the period after
admission was included in the study)?
Aren't the responses of the GCS score covered in the NIHSS, which also
includes an assessment of consciousness? So why include the GCS in addition
to the NIHSS?
Age was included as a linear variable in the model, yet the final score uses
categories. How were these categories selected? Was there any test done for a
departure from linear trend for age?
How reliable is the recording of the risk factors and outcomes within the
datasets? Has there been any validation of the variables used in the dataset?
What is the distribution of the score in the study population? Do most people
have a score of zero or is it evenly distributed?
What is the cross over between the CNSR and the CICAS? If these datasets
come from the same hospitals then the CICAs would not be an external
validation.
The detail for the comments above was lacking in the methods. I had to deduce it
from the discussion and tables but this should have been in the methods.
Level of interest: An article whose findings are important to those with closely
related research interests
Quality of written English: Acceptable
Statistical review: Yes, and I have assessed the statistics in my report.
Declaration of competing interests:
I declare that I have no competing interests
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