Acute chemical ingestion in the under 19 population in South Korea: A brief report

Jae Hee Lee; Duk Hee Lee

doi:10.1371/journal.pone.0242430

Peer Review History

Original SubmissionSeptember 15, 2020
6 Oct 2020 Decision Letter - Martina Crivellari, Editor PONE-D-20-27951 Clinical outcomes of acute chemical ingestions in pediatrics and adolescents admitted to Emergency department, South Korea PLOS ONE Dear Dr. Duk Hee Lee, Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process. After a statistician analysis we conclude that the sample size is too small especially for intentional group. Some crucial factors were not measured or reported. We recommend the authors to simplify the analysis and re-write the manuscript as a brief report. 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(Please upload your review as an attachment if it exceeds 20,000 characters) Reviewer #1: The retrospective study reported the major types of chemical poisoning agents in pediatrics patients who visited ED in South Korea from 2011 to 2016 and accessed the associations between hospital admission and potential risk factors. The authors published a similar study for adult patients using the same database, study design and analytic methods. The sample size of intentional group is too small to be analyzed using multiple logistic regression with so many dummy covariates. Most of chemical ingestions cannot be included in analysis due to a lack of cases. The result of multivariable analysis of intentional chemical ingestion for admission is bias. I recommend to simplify the analysis and re-write the manuscript as a brief report. For pediatrics especially for young age kids, exposure concentrations / doses and period from time of arrival to ED admission are crucial factors. However, the authors didn’t collect and report the corresponding data. It may bring significant bias by ignoring those two factors. Are there any clinical/statistical reasons to divide the ages into three groups? It makes the tables too complicated and may dilute the primary take home message. For categorical characteristics with more than two categories, it is suspected and tedious to report p-values of Chi-square tests of each category without multiple adjustment. I recommend to perform one single Chi-square test for categorical characteristics and report a single p-value. Almost all patients in intentional group reported “Other” for activity (101/102). Is there free text clarification available in database? Reporting total in tables is tedious. Also, for sex and day of presentation, reporting one category is good enough. The author didn’t clearly illustrate covariates and the corresponding variable selection method used in multiple logistic regression. ****** 6. 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Revision 1
27 Oct 2020 Author Response I appreciate your careful reading and proper comments. Reviewer #1: The retrospective study reported the major types of chemical poisoning agents in pediatrics patients who visited ED in South Korea from 2011 to 2016 and accessed the associations between hospital admission and potential risk factors. The authors published a similar study for adult patients using the same database, study design and analytic methods. The sample size of intentional group is too small to be analyzed using multiple logistic regression with so many dummy covariates. Most of chemical ingestions cannot be included in analysis due to a lack of cases. The result of multivariable analysis of intentional chemical ingestion for admission is bias. I recommend to simplify the analysis and re-write the manuscript as a brief report. RESPONSE: We agree that multiple logistic regression is not appropriate because the sample size of the intentional group is small. After analyzing the study population by dividing it into intentional and unintentional ingestion groups, subgroup analysis was conducted only for the unintentional group. The analysis was simplified and edited in the form of a brief report. For pediatrics especially for young age kids, exposure concentrations / doses and period from time of arrival to ED admission are crucial factors. However, the authors didn’t collect and report the corresponding data. It may bring significant bias by ignoring those two factors. RESPONSE: The lack of information on the concentration and amount of chemicals is a clear limitation of this study, but I think it makes sense to understand the common types of chemicals ingested by pediatric patients. The period from arrival to admission to ED is indicated in the table as “Time Interval from Injury to ED Visit” (Tables 1 and 3), and there was no significant difference between the discharge and admitted subgroups in the unintended ingestion group. Are there any clinical/statistical reasons to divide the ages into three groups? It makes the tables too complicated and may dilute the primary take home message. RESPONSE: We agree with your opinion that the classification is difficult to understand. However, among children, the characteristics of the preschool age, school age, and adolescent age are very different. The same criteria have been used in the “2017 Annual Report of the American Association of Poison Control Centers’ National Poison Data System (NPDS): 35th Annual Report” to analyze the distribution by age group. For categorical characteristics with more than two categories, it is suspected and tedious to report p-values of Chi-square tests of each category without multiple adjustment. I recommend to perform one single Chi-square test for categorical characteristics and report a single p-value. RESPONSE: The analysis was re-run to derive a single p-value, and Fisher's exact test was used when the expected count for less than 5 cells was 25% or more. Almost all patients in the intentional group reported “Other” for activity (101/102). Is there free text clarification available in the database? RESPONSE: The free text clarification is summarized as follows: Statistics Activity_others N Valid 102 Missing 0 Activity_others Frequency Percent Valid Percent Cumulative Percent Valid 1 1.0 1.0 1.0 Toxic ingestion 2 2.0 2.0 2.9 Suicide 21 20.6 20.6 23.5 Suicide/self-harm 1 1.0 1.0 24.5 For suicide 3 2.9 2.9 27.5 Suicidal attempt 35 34.3 34.3 61.8 Suicidal attempt/self-harm 1 1.0 1.0 62.7 Self-harm 13 12.7 12.7 75.5 Self-harm or suicide 2 2.0 2.0 77.5 Attempt of self-harm 1 1.0 1.0 78.4 Self-harm, suicide 3 2.9 2.9 81.4 Self-harm/suicide 1 1.0 1.0 82.4 Self-harm suicide 18 17.6 17.6 100.0 Total 102 100.0 100.0 Reporting total in tables is tedious. Also, for sex and day of presentation, reporting one category is good enough. RESPONSE: Reflecting your point of view, we have categorized the items with a frequency less than 0.5% as “others” and added a description at the bottom of the table. The author didn’t clearly illustrate covariates and the corresponding variable selection method used in multiple logistic regression. RESPONSE: As shown in Table 3, among the variables collected in this study, the variables that showed significant differences in the univariate analysis were age and ED stay. However, ED stay was excluded because it was not a factor that contributed to the severity of the patient. Therefore, in the multiple logistic regression, age and ingested chemicals were selected and implemented, and significant variables obtained by backward stage selection (likelihood ratio) are presented in Table 4. This explanation is added to the text. https://doi.org/10.1371/journal.pone.0242430.r002
3 Nov 2020 Decision Letter - Martina Crivellari, Editor Acute chemical ingestion in the under 19 population in South Korea: a brief report PONE-D-20-27951R1 Dear Dr. Hee Lee, We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements. Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication. An invoice for payment will follow shortly after the formal acceptance. To ensure an efficient process, please log into Editorial Manager at http://www.editorialmanager.com/pone/, click the 'Update My Information' link at the top of the page, and double check that your user information is up-to-date. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org. If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org. Kind regards, Martina Crivellari Academic Editor PLOS ONE Additional Editor Comments (optional): Reviewers' comments: https://doi.org/10.1371/journal.pone.0242430.r003
Formally Accepted
5 Nov 2020 Acceptance Letter - Martina Crivellari, Editor PONE-D-20-27951R1 Acute chemical ingestion in the under 19 population in South Korea: a brief report Dear Dr. Lee: I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department. If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org. If we can help with anything else, please email us at plosone@plos.org. Thank you for submitting your work to PLOS ONE and supporting open access. Kind regards, PLOS ONE Editorial Office Staff on behalf of Dr. Martina Crivellari Academic Editor PLOS ONE https://doi.org/10.1371/journal.pone.0242430.r004

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