Review for 10.1186/1471-230X-11-55 (2011)

Reviewer's report
Title:The relationship between unrecognized gastroesophageal reflux disease
and excessive daytime sleepiness in Taiwan: A pilot study
Version: 2Date:9 November 2010
Reviewer: William C Orr
Reviewer's report:
This is an interesting study which is properly noted to be a pilot study. It
addresses the prevalence of presumed GERD related sleep disturbance in
patients referred for possible liver disease in whom no liver disease is detected.
This provocative study draws attention to an underlying problem which is relevant
not only to gastroenterologists, but to primary care physicians as well. My
specific comments are as follows:
1. The biggest flaw in this study is the lack of any data on the prevalence and
frequency of nighttime heartburn in this patient population. Is there any way to
achieve this from any of the formal or informal assessments which were done on
these patients (doesn’t the GERD questionnaire ask about nighttime heartburn?)
Without any information on nighttime heartburn and no esophageal testing there
is really nothing to suspect nighttime GERD as a cause of the EDS except the
presumption that most (estimated at 70-75%) of GERD patients have nighttime
heartburn. In a substantial portion of these patients report that nighttime
heartburn does result in some daytime consequences. These studies need to be
discussed in detail in the context of their data and lack of any information
reported on nighttime heartburn (Farup et. al. Arch. Intern. Med. 2001: 161;
45-62; Shaker et. al. Amer. J. Gastroenterol. 2003: 98; 1487-1493)
2. The purpose and aim of the study needs to be restated to reflect the study
population which is patients in whom EDS was felt to be “…related to an
underlying liver disease…” but in whom no liver disease was identified. This
properly identifies the study population.
3. Can the authors more carefully describe patients who were referred? That is
can they state in general what types of complaints or clinical profile lead the
referring physicians to suspect EDS secondary to a liver disease? I presume no
assessment of liver disease was done by the primary care physician since a
substantial portion of these patients had normal liver function tests.
4. It is noted that 91.8% of the patients denied snoring, yet the GERD group had
significantly greater percentage of patients who reported snoring. Is it possible
that some of these patients did have unrecognized obstructive sleep apnea?
Some comment on this in the discussion would be appropriate.
5. The authors report that the ESS score in the entire cohort is 6.32 and the
score in the “normal community” is 5.9. This is a trivial difference and I would
omit any reference to this difference.
6. The authors comment on a report in the literature (ref #5) that the prevalence
of nocturnal GERD is 54%. This is presumably in a population of GERD patients.
I have noted above that the authors should specifically comment on the studies
by Shaker et. al. and Farup et. al. which notes the prevalence of nighttime
heartburn to be substantially higher.
7. On a couple of instances I believe the authors have referred to ESD when they
meas EDS.