Review for 10.1186/1471-230X-11-102 (2011)

Reviewer's report
Title:Social disparities in the use of colonoscopy by primary care physicians in
Ontario
Version: 5Date:23 December 2010
Reviewer: Geoff M Forbes
Reviewer's report:
Major revisions
1. The concept of "use" of Cy- whether this is by the PCP, or alternatively patient.
The manuscript is ostensibly about PCP use, but how this can be distinguished
from "patient use" is muddied in places.
2a. "Discretionary Cy". This is a theme throughout the paper, and one I have
concerns about. I understand what the authors are trying to get at, but feel this
issue requires attention. Some exampes of where I had some misgivings were:
methods section- definition of "discretionary Cy"; is Cy ever "discretionary"; table
2 suggests the vast majority of Cy was considered "discretionary"; when does
discretionary Cy become "unnecessary Cy"; accordingly the conclusion implies
lack of Cy access to socio-economically disadvantaged- maybe a contrary view
is that the SE advantaged are having Cy too readily!
2b. In the limitations section of the discussion the authors state: "We made the
reasonable assumption that a Cy was 'functionally' a screening procedure
(discretionary) if there was no discernible clinical indication for the
procedure......". How did they determine this? They go onto state:".......the vast
majority of Cy performed- even those in patients with GI symptoms or in whom a
diagnosis of CRC may be suspected- are actually discretionary in nature." I am
afraid that I disagree strongly with this statement.
3. Older PCPs were more likely to refer for Cy; equally older patients were more
likely to have Cy. Do older patients have older PCPs? I could not gather from the
paper whether this has been teased out. Same issue applies to gender.
4. Methods, "identification of screen-elibible patients", last sentance first
paragraph: ".... most Cy done in patients with no GI symptoms, or mild
symptoms....." What is the evidence for this?
5. Methods: excluded were patients residing in regions where physicians do not
direct bill. What percentage of the cohort are we then missing?
6. Methods; identification of Cy; last sentance: some patients had direct access
Cy without first being seen by a physician; others were seen by a physician first-
do the authors know the relative proportion, and how might this influence results?
For example, when referred appropriately, direct access Cy can be very effective
at minimising waiting times and expediting Cy; when done badly, the converse,
and different physicians will have different practices in vetting the
appropriateness for the Cy.
7. Results, paragraph 4: "there appears to be.......", and "Fig 2 illustrates
trends........". Suggest this is modified. There either is an increase or there is not.
8. Discussion: first statement: "....access....". I would prefer to see a different
word used. Access can be measured in a number of ways (eg waiting times).
Simply because one PCP "utilises" Cy services more than another doesn't
necessarily mean those patients have different levels of access
9. Table 1: there are trends with time within the characteristics of the PCPs and
their patients; PCPs older, longer in practice; patients younger, fewer with
comordidities, etc- what are the implications of this?
10 Table 4: for several parameters the magnitude of difference is small, yet
statistical significance was found (eg yrs of PCP experience, patient age, rural
location, in work)- what are the real implications?
Minor revisions
1. Methodology is somewhat lengthy.
2. Fig 1 not needed as data are given in table 3
3. There is a tremendous amount of information in fig 2, could this be modified
downwards?
Discretionary revisions
1. Abstract, background: "The rate of colonoscopy...." I might have chosen a
different term to "rate". Further this background statement forms part of the
results data, which is unfortunate
2. Methods, "identification of screen-elibible patients". Sentance 2 and 3 are
repetitive
Level of interest: An article whose findings are important to those with closely
related research interests
Quality of written English: Acceptable
Statistical review: Yes, but I do not feel adequately qualified to assess the
statistics.
Declaration of competing interests:
I declare that I have no competing interests