Review for 10.1186/1471-230X-12-136 (2012)

Reviewer's report
Title:Use of health care services and pharmaceutical agents in coeliac disease:
a prospective nationwide study
Version: 1Date:23 July 2012
Reviewer: Alberto Lanzini
Reviewer's report:
Major compulsory revision
1. Methods
a. The questionnaire sent to celiac patients is not adequately described. Authors
make reference (n 14) to a previous publication that, however, does not describe
the questions asked for the present study (use of health care services and
pharmacological agents). Information on methods of measurement (n of pills per
months, etc) should be detailed in the Methods section, and not as a foot note on
tables.
b. It is unclear whether the “key items” used for the “test-retest reliability”
validation of the questionnaire reported in reference 14 included some of the
items reported in the present study. This point needs to be specified in the
Methods and commented on in the Discussion.
c. Celiac patients and subjects in the general Finnish population were studied
with two different questionnaire presumably differing for face, content and
number of questions. These differences should be outlined in the Methods
section, and the fact that the two cohorts were studied with different
questionnaires should be commented on in the Discussion as a weakness of the
study. Was any celiac patient tested with both questionnaire to assess
concordance? This would add to the quality of data.
d. There is no definition of the categories of clinical presentation particularly in
relation to patients “detected by screening” (family screening? associated
diseases?).
2. Results
a. Response rate is very low with 770 valid returns out of 1864 questionnaires
sent off, i.e. 38% response rate. This low 38% figure should be clearly indicated
in the results, and commented on in the Discussion as a source of potential bias.
b. A table with characteristics of subjects in the general population should be
included. Age range was the same in the two cohorts but no information is
available on age distribution of the two cohorts, and this information is important
because use of health resources increases with age. An age related analysis
similar to that carried out for sick leave (Results, third paragraph) may be
relevant.
c. Figures 1 and 2 are missing making impossible to understand a large
proportion of results.
d. How many patients reported sick leave in the two cohorts? If the number is low
this result are likely to be spurious and this should be commented in the
Discussion. On a more general basis the actual number or proportion of patients
reporting use of services or medicines is not reported and would be desirable.
3. Discussion
a. Appropriateness of discussion cannot be commented on because of lack of
Figures 1 and 2.
b. Last paragraph. Beside discussing strength of the study, weakness should
also be recognized in particular in relation to potential bias due to a) different
questionnaires used to study the two cohorts; b) low response rate of celiacs to
questionnaire; c) and, should this be the case, small numbers presumably
involved in some comparisons (sick leave?).
4. Minor essential revisions
a. Abstract: the use of 2 postal questionnaires should be mentioned in the
Methods
b. Results. Table 1. Celiacs “detected by screening” were 21% of the whole
cohort: how many of these patients had associated diseases that per se may
affect the use of health care services (for example IDDM)? This point may
deserve a comment in the Discussion.
c. Discussion, paragraph n 7. Are the Authors implying that use of antibiotics is a
risk factor for celiac disease as reported for IBD? The whole paragraph is
confusing and should be clarified.
d. Was the study approved by an Ethics Committee? This point should be
specified.
5. Discretionary revisions
a. Discussion, paragraph n 8: increased use of vitamins and micronutrients is
worrying in relation to cancer risk (see www.dietandcancerreport.org) and this
point may deserve a comment in the Discussion.
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 declare that I have no competing intersts