Review for 10.1186/s12876-022-02429-0 (2022)

Title: Mortality and complications after percutaneous endoscopic gastrostomy, a retrospective
multicentre study
Version: 1 Date: 01 Jun 2022
Reviewer:  Shigenori Masaki
Reviewer's report:
This retrospective study focuses on mortality and complications after percutaneous endoscopic
gastrostomy (PEG). PEG has two roles: gastric decompression and enteral nutrition. In an aging
society, patients with older age and malnutrition may undergo PEG due to various underlying
diseases. It is crucial to provide safe PEG to such patients who require PEG. To that end, it is
necessary to analyze the outcomes after PEG. The research theme of the authors is important.
The manuscript is well written. However, there are some points that need to be addressed in this
manuscript. I have several comments below:
1. TITLE
“Mortality and complications after percutaneous endoscopic gastrostomy, a retrospective
multicentre study”
Comment: I think it is common to use a colon instead of a comma.
“…endoscopic gastrostomy: a retrospective multicentre study”
2. Background
Page 3, first paragraph: “The main indications for PEG placement are stomach decompression
and enteral feeding, mostly caused by neurological disease, obstructive cancer (e.g. head-neck
cancer or esophagus cancer) or trauma (2).”
Comment: This sentence is misleading. Indication of PEG for enteral nutrition is dysphagia
caused by neurological disease, obstructive cancer (e.g. head-neck cancer or esophageal cancer),
head trauma, etc., whereas indication of PEG for gastric decompression is malignant bowel
obstruction. Please revise this sentence.
Page 3, second paragraph, first sentence: “… two different surgical methods have evolved”
Comment: "Surgical methods" should be rewritten as simply "methods" or "insertion methods".
Page 3, second paragraph: “The latter method requires the gastrostomy tube to be pulled past
the patients’ pharynx and oesophagus.”
Comment: I think it is better to describe both the push method and the pull method in this
paragraph. For example, “The gastrostomy tube is pushed and placed in the former method,
and pulled and placed in the latter method. The tube passes through the patient's pharynx and
esophagus in either method.”
3. Method
Study design and data collection
Page 5: “Patient characteristics, if any complications had occurred within 30 days of the
procedure, mortality within 30 and 90 days and cause of death were then collected from their
medical journals.”
Comment: This sentence gives the impression that mortality data for patients without
complications were not collected. Did the authors collect 30-day and 90-day mortality data
for patients without complications? If not, did the authors treat such cases as survival cases or
censored cases in the analysis? And I think it is better to revise "medical journal" to "medical
record" or "medical chart" throughout the manuscript.
Variables and statistical methods
Page 5, first paragraph, first sentence: “…mortality at 90 days, minor complications, and major
complications.”
Comment: Please define minor and major complications here although complications are listed
in Table 5. Abdominal pain is included in the minor complications, but I think patients after
PEG generally feel more or less abdominal pain (wound pain). Please describe the definition of
abdominal pain in this study or exclude abdominal pain from minor complications.
Page 5, first paragraph, third sentence: “…, malignancy (tumour obstruction) and…”
Comment: Esophageal stenosis caused by esophageal cancer is indication of PEG for enteral
nutrition. Malignant bowel obstruction due to colorectal cancer, ovarian cancer, etc. is indication
of PEG for gastric decompression. Please specify which types of cancer are included in this
study.
4. Results
“See table 1” “see table 2” “see figure 1”…
Comment: The expressions “See table 1” “see table 2”… are repeatedly used. Please consider
revising “Baseline data and patient characteristics are shown in Table 1” “The most common
cause of death was malignancy, followed by aspiration pneumonia (Table 2)” and so on.
Mortality
“There was also a clear, although not statistically significant, trend that malignancy was
associated with higher mortality at 30 days (OR 2.10, 95% CI 0.95-4.68).”
Comment: Please remove this sentence. The authors should not emphasize insignificant results.
“Mortality at 90 days was significantly higher for women (OR 1.95, 95% CI 1.11–3.44)”
Comment: I would like to ask about this result. This result is inconsistent with the results of
previous studies. Thus, I tried to reverify the authors’ results. As far as I performed a univariate
analysis based on the authors’ data, the unadjusted odds ratio for female sex was 1.24 (95% CI
0.79-1.93). I am sorry but I do not think female sex would be such a significant variable with an
odds ratio of 1.95 (95% CI 1.11-3.44) as the authors showed as a result of multivariate analysis.
It is hard to say this, but is it possible that there was an error in the analysis process? Please
check the analysis process once again.
Complications
“, in the adjusted analyses this difference was however not significant although it shown a clear
trend for less complications (OR 0.55, 95% CI 0.24-1.27).”
Comment: Please remove this sentence. The authors should not emphasize insignificant results.
5. Discussion
Page 8, first paragraph: “There was also a clear, although not statistically significant, trend for
higher mortality at 30 days among those that had malignancy as indication.”
Comment: Please remove this sentence. The authors should not emphasize insignificant results.
Page 8, second paragraph: “The main exposure and outcome of our study contrasts with
those of several previous studies, which found higher mortality rates for those suffering from
neurological deficit, whereas in our study malignancy was associated with a higher mortality
rate.”
Comment: I have a rather different opinion. Malignancy has been often reported to be the factors
associated with poorer survival among patients with PEG tubes (a). Therefore, malignancy has
been often excluded from the survival analysis after PEG in various studies to evaluate the
survival effects of PEG (b)(c). Because malignancy is already recognized as prognostic factor.
In particular, the prognosis for malignant tumors requiring gastric decompression is worse (d).
Thus, I think the results of the authors’ study are consistent with previous studies. Please revise
this sentence.
References
a). Mitchell SL, Tetroe JM. Survival after percutaneous endoscopic gastrostomy placement in
older persons. J Gerontol A Biol Sci Med Sci. 2000; 55: M735–9.
b). Tamiya H, Yasunaga H, Matusi H, et al. Comparison of short-term mortality and morbidity
between parenteral and enteral nutrition for adults without cancer: a propensity-matched analysis
using a national inpatient database. Am J Clin Nutr. 2015 Nov;102(5):1222-8.
c). Suzuki Y, Tamez S, Murakami A, et al. Survival of geriatric patients after percutaneous
endoscopic gastrostomy in Japan. World J Gastroenterol. 2010 Oct 28;16(40):5084-91.
d). Kawata N, Kakushima N, Tanaka M, et al. Percutaneous endoscopic gastrostomy for
decompression of malignant bowel obstruction. Dig Endosc. 2014 Mar;26(2):208-13.
Page 8, second paragraph: “Earlier referral for patients with malignancy in need for PEG would
probably benefit these patients, especially when considering the high mortality rates among
those with malignancy.”
Comment: It may be better to describe why PEG is beneficial (e.g. PEG relieves the patient from
discomfort due to nasogastric tube and improves the patient's quality of life).
Page 9: “Probably, there are more women who could benefit from PEG but are either never
referred for the procedure or are denied more often than men are.”
Comment: Is it possible that women had a higher rate of older age, malnutrition, lower BMI,
and malignancy than men in this study?
Page 9: “If we excluded aspiration pneumonias as a complication, the number of major
complications would be 15 (4%), which is more in line with previous studies.”
Comment: Please remove this sentence. The authors should not show new results that are not
shown in the results section.
Page 10: “To further examine this, we also compared patient characteristics between the two
hospitals, and the patients at the hospital with less adverse outcomes were on average 4 years
younger, had less comorbidities and lower CRP.”
Comment: Please remove this sentence. The authors should not show new results that are not
shown in the results section. If the authors want to describe this result, please show it in the
table in the results section.
6. Conclusion and Abstract
Comment: Please revise these sections appropriately based on the revisions of other sections.
7. Table 1
Comment: In the operation method section, the Pull method percentage should be 67% and the
Push method percentage should be 24% (Because the missing data is 8%).
Please specify the unit of C-reactive protein, Haemoglobin, Thrombocytes, Albumin, and
Creatinine.
8. Table 3
Comment: Variables "year of procedure" and "hospital" are not shown in Table 3. Please add
these data.