Review for 10.1186/1471-230X-14-165 (2014)

Reviewer's report
Title:Yield of Endoscopic ultrasound in patients with moderate and high
likelihood of suspected choledocholithiasis: a retrospective study from a single
university based- endoscopic center
Version:2Date:30 June 2014
Reviewer: Vani Konda
Reviewer's report:
Yield of Endoscopic ultrasound in patients with moderate and high likelihood of
suspected choledocholithiasis: a retrospective study from a single university
based-endoscopic center.
Prachuayakul et al provide their retrospective experience on the utility of
endoscopic ultrasound in the diagnosis of choledocholithiasis for moderate and
high likelihood cases. The study does raise the important notion worthy of
consideration to perform EUS in high likelihood cases in addition the
recommended moderate likelihood cases. However, there are some additional
points of consideration for this manuscript in regards to reporting on the
diagnostic parameters of EUS in this retrospective fashion.
Major Compulsory Revisions
1. Could we get more information on the baseline population? Is the population of
patients who underwent EUS generalizable to all of the patients presenting with
suspicion of choledocholithiasis in their institution? There were 93 patients who
underwent EUS and had suspicion of a stone, but does this make up most or a
few of all the patients with suspicion for a stone? Do we know if most of the high
likelihood patients went straight to ERCP and bypassed the EUS at this
institution? Was the ratio of intermediate vs. high similar to those who underwent
EUS and those that did not?
2. The study utilizes ERCP as the gold standard for the diagnosis of CBD stones.
However, not all patients had the gold standard test. They provide some follow
up data but more needs to be in place to have the follow up data be a robust
enough reference standard for those patients who had not undergone ERCP.
How many patients were followed up or lost? What was the range and median
time of follow up. Was there any follow up imaging performed? Were lab values
available on all these patients. Are all patients who may subsequently passed a
stone but not presented to the hospital captured? Since this in essence is the
reference standard that the authors need to rely on to determine if there is a false
negative, more convincing detail needs to be provided.
3. For the sensitivity, specificity, PPV, and NPV, could the authors please add the
raw numbers of the numerator and denominator in parenthesis? If adequate
reference standard is not achieved on those patients who have not undergone
ERCP, then there should be caution in reporting the diagnostic parameters.
4. There is no statistics section.
Minor Essential Revisions
5. I found the time comparisons with the 7 day cut of difficult to follow in the
current table. It may deserve its own table with the data more clearly presented.
6. I found the reference for the poster presented at DDW 2011 difficulty to
identify. Was this from the author’s institution? If so, could more detail be
provided?
7. Limitations of the retrospective nature of the study and lack of gold standard
present on all patients needs to be addressed.
Discretionary Revisions
8. Some of the background and discussion are redundant. Could the authors
save the comments of other studies for 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: Yes, but I do not feel adequately qualified to assess the
statistics.
Declaration of competing interests:
I declare that I have no competing interests.