Reviewer's report
Title:Chronic fatigue syndrome after Giardia enteritis: clinical characteristics,
disability and long-term sickness absence.
Version: 3Date:16 June 2011
Reviewer: Peter White
Reviewer's report:
I have read the revised report, but I am afraid to say there are still major
methodological problems with this report.
1. The authors use the denominator of 1262 patients, when the real denominator
is 96.
2. The authors say they used the Reeves et al criteria for diagnosing CFS, but
this recommends using a standardised psychiatric interview, which they did not
do. A HADS scale does not, for instance, measure recent history of psychiatric
disorders, which is necessary to make a CDC diagnosis of CFS. The authors
continue to use the wrong threshold for judgement of clinical depression and
anxiety of 15. The original authors of the HADS clearly state it is 8-10 for
borderline and 10+ for clinically significant mood disorders on the two sub-scales.
With this standard of measurement, not complying with CDC criteria, I cannot be
confident that the 56 patients did have CFS.
3. Their main aim is to describe the phenotype of CFS after giardiasis, but they
make no empirical analysis of the phenotype.
4. The relationship between giardiasis and CFS cannot be assumed to be
causative when there is a delay in development of CFS after infection of months.
5. The fundamental problem is that the authors explicitly interpret their data as
though it was an epidemiological study of the relationship between giardiasis and
CFS, when it is not. The authors overintrepret what is essentially a case series of
patients who have been referred to a hospital for fatigue some time after
contracting giardiasis.
Level of interest: An article of limited interest
Quality of written English: Acceptable
Statistical review: No, the manuscript does not need to be seen by a
statistician.
Declaration of competing interests:
I advise the UK government and a re-insurance company about disability related
to medically unexplained symptoms and mental health.
Reviewer's report
Title:Chronic fatigue syndrome after Giardia enteritis: clinical characteristics,
disability and long-term sickness absence.
Version: 3Date:16 June 2011
Reviewer: Peter White
Reviewer's report:
I have read the revised report, but I am afraid to say there are still major
methodological problems with this report.
1. The authors use the denominator of 1262 patients, when the real denominator
is 96.
2. The authors say they used the Reeves et al criteria for diagnosing CFS, but
this recommends using a standardised psychiatric interview, which they did not
do. A HADS scale does not, for instance, measure recent history of psychiatric
disorders, which is necessary to make a CDC diagnosis of CFS. The authors
continue to use the wrong threshold for judgement of clinical depression and
anxiety of 15. The original authors of the HADS clearly state it is 8-10 for
borderline and 10+ for clinically significant mood disorders on the two sub-scales.
With this standard of measurement, not complying with CDC criteria, I cannot be
confident that the 56 patients did have CFS.
3. Their main aim is to describe the phenotype of CFS after giardiasis, but they
make no empirical analysis of the phenotype.
4. The relationship between giardiasis and CFS cannot be assumed to be
causative when there is a delay in development of CFS after infection of months.
5. The fundamental problem is that the authors explicitly interpret their data as
though it was an epidemiological study of the relationship between giardiasis and
CFS, when it is not. The authors overintrepret what is essentially a case series of
patients who have been referred to a hospital for fatigue some time after
contracting giardiasis.
Level of interest: An article of limited interest
Quality of written English: Acceptable
Statistical review: No, the manuscript does not need to be seen by a
statistician.
Declaration of competing interests:
I advise the UK government and a re-insurance company about disability related
to medically unexplained symptoms and mental health.
Please review this paper.
user
Reviewer's report
Title:Chronic fatigue syndrome after Giardia enteritis: clinical characteristics,
disability and long-term sickness absence.
Version: 3Date:16 June 2011
Reviewer: Peter White
Reviewer's report:
I have read the revised report, but I am afraid to say there are still major
methodological problems with this report.
1. The authors use the denominator of 1262 patients, when the real denominator
is 96.
2. The authors say they used the Reeves et al criteria for diagnosing CFS, but
this recommends using a standardised psychiatric interview, which they did not
do. A HADS scale does not, for instance, measure recent history of psychiatric
disorders, which is necessary to make a CDC diagnosis of CFS. The authors
continue to use the wrong threshold for judgement of clinical depression and
anxiety of 15. The original authors of the HADS clearly state it is 8-10 for
borderline and 10+ for clinically significant mood disorders on the two sub-scales.
With this standard of measurement, not complying with CDC criteria, I cannot be
confident that the 56 patients did have CFS.
3. Their main aim is to describe the phenotype of CFS after giardiasis, but they
make no empirical analysis of the phenotype.
4. The relationship between giardiasis and CFS cannot be assumed to be
causative when there is a delay in development of CFS after infection of months.
5. The fundamental problem is that the authors explicitly interpret their data as
though it was an epidemiological study of the relationship between giardiasis and
CFS, when it is not. The authors overintrepret what is essentially a case series of
patients who have been referred to a hospital for fatigue some time after
contracting giardiasis.
Level of interest: An article of limited interest
Quality of written English: Acceptable
Statistical review: No, the manuscript does not need to be seen by a
statistician.
Declaration of competing interests:
I advise the UK government and a re-insurance company about disability related
to medically unexplained symptoms and mental health.
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