Review for 10.1186/1471-230X-8-8 (2008)

Reviewer's report
Title:A self administered reliable questionnaire to assess lower bowel symptoms
Version: 1Date:24 November 2007
Reviewer: David Cade
Reviewer's report:
General
This paper has value as it confirms what has previously been published but in a
different manner. The essential conclusion is that if a patient is given a
questionnaire with specific questions on their own symptoms they are likely to
answer the questions in the same way 2 weeks later. Furthermore if these same
questions are asked by a doctor the results are remarkably similar to the answer
written by the patient.
A comprehensive bowel symptom questionnaire was used in a study by
Selvachandran et al in 2002 (1) of which I was a co-author, with similar questions
to those on the questionnaire used by these authors. These symptoms were
benchmarked against the diagnosis of cancer. Sensitivity, specificity, positive
predictive values and relative risk were assessed for individual symptoms and
emphasis made on combinations of symptoms (weighted numerical score). This
is validation.
Unfortunately a useful contribution to the undoubted place for symptom
questionnaires has, by a process of semantics, diminished its impact by failing to
give a balanced discussion and review of appropriate literature.
(1) Selvachandran SN, Hodder RJ, Ballal MS, Jones P, Cade D. Prediction of
colorectal cancer by a patient consultation questionnaire and scoring system: a
prospective study. The Lancet 2002;360:278-283
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Major Compulsory Revisions (that the author must respond to before a decision
on publication can be reached)
1 The authors use the terms "reliable" and "validated" incorrectly and by so doing
claim that there are no "validated" questionnaires and therefore imply that they
have something original. By using this subterfuge they have avoided discussion
of previous work. Reliability is a measure of comparison of one thing with another
with a degree of robustness; validity needs a gold standard to benchmark
against.
2 By comparing patients in the same group at a 2 week interval they have
performed an "internal correlation". These 2 cohorts are "dependent" and
therefore it is hardly surprising that agreement has a high kappa value. Kappa
value is a measure of "independent" cohort agreement and therefore it is
reasonable to derive a kappa value just for the patient/doctor assessments of the
questionnaire. For this assessment Cronbach's alpha is recommended for
internal consistency of the questionnaire without that the data cannot be relied
on.
3 An adequate discussion is required as detailed in the general comments.
References and discussion should include a paper Hodder et al 2005 (2)
(2) Hodder RJ, Ballal M, Selvachandran SN, Cade D. Pitfalls in the construction
of cancer guidelines demonstrated by the analyses of colorectal referrals. Ann R
Coll Surg Engl 2005;87:419-426
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Minor Essential Revisions (such as missing labels on figures, or the wrong use of
a term, which the author can be trusted to correct)
We should know when the patients filled in the questionnaire, especially if it was
filled in in the waiting room whilst awaiting to see the doctor. In these
circumstances patients are distracted and accuracy is compromised.
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Discretionary Revisions (which the author can choose to ignore)
What next?: Unable to decide on acceptance or rejection until the authors have
responded to the major compulsory revisions
Level of interest: An article whose findings are important to those with closely
related research interests
Quality of written English: Acceptable
Statistical review: No, the manuscript does not need to be seen by a
statistician.
Declaration of competing interests:
I was a co-author of the papers that I feel should have been discussed.