PONE-D-19-25768

Obstructive sleep apnea and hypopnea syndrome in patients admitted in a tertiary hospital in Cameroon: prevalence and determinants

PLOS ONE

Dear Dr. Poka-Mayap,

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.

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Please take a close look at the comments of Reviewer #1 who has made many specific comments that will improve the readability of the manuscript. 

In addition to the above, this editor has questions re: the analysis for moderate-severe OSA.  It is not clear to me why BMI is not included in the analysis and why an age>58 was chosen as a cutoff. Also, the authors could consider using the STOP-BANG as a factor for prediction as the STOP-BANG has been shown to be predictive of moderate-severe OSA.

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We would appreciate receiving your revised manuscript by Nov 23 2019 11:59PM. When you are ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

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James Andrew Rowley

Academic Editor

PLOS ONE

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1. Please include additional information regarding the STOP-BANG questionnaire used in the study and ensure that you have provided sufficient details that others could replicate the analyses. For instance, if you developed a questionnaire as part of this study and it is not under a copyright more restrictive than CC-BY, please include a copy, in both the original language and English, as Supporting Information.

2. In your Methods section, please provide additional information about the participant recruitment method and the demographic details of your participants. Please ensure you have provided sufficient details to replicate the analyses such as: a) the recruitment date range (month and year), b) a description of any inclusion/exclusion criteria that were applied to participant recruitment,  and c) a description of how participants were recruited.

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

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2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

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Reviewer #1: No

Reviewer #2: No

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Reviewer #1: Yes

Reviewer #2: Yes

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5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: 1.AHI should replace OAHI : the standard abbreviation is AHI (Apnea hypopnea index) which makes your article more searchable. Also unless you have excluded the few central events which may coexist with obstructive events in OSAHS, then OAHI is a misnomer.

2. Rephrase last sentence in the conclusion of the abstract " Screening...in patients especially "in those with" hypertension....

3. Abstract conclusion: I do not agree screening is mandatory in all in patients with hypertension but rather in 1) those with resistant hypertension and 2) in those with hypertension and additional risk factors for .

4. Line 66 and 68 of introduction: Define "sleep records", describe what you mean by "particular groups of patients" so the readers understand exactly what you are referring to.

5. Line 105 in data collection: propensy should be "propensity"; after ESS insert "which"

6. Line 126 of Diagnosis of OSAHS: what is illisible? likely a typo, please correct

7. Line 131 of Diagnosis of OSAHS: consider taking out obstructive and using the universal term "Apnea hypopnea index" except all central events were excluded from the calculation

8. Line 132 of Diagnosis of OSAHS: consider changing total registration time to "total recording time" which is a more universal term. Thiswill need to be changed throughout the manuscript and in the tables if applicable.

9. Table 1: please correct all p values with commas inserted instead of decimal points. These are probably erroneous. Also ensure p values are placed in the appropriate rows for which they were calculated.

10. Table 2: again correct p values with commas instead of decimal points

11. Line 227: please rephrase, using the word "but" suggests that a lower median arterial oxygen saturation is associated with lower ESS scores, which it is not. Consider expressing these 2 findings as separate sentences.

12. Table 4: if changing total registration time to total recording time as discussed above, then correct it in this table, also OAHI to AHI. also correct p values with commas instead of decimal points. Change this in Lines 233 and 234 as well (OAHI to AHI)

13. Lines 238 to 239: The numbers do not add up. If 111 had valid data per the Results on line 162 then 6 particants are unaccounted for (40 - No OSA, 65 had OSAHS (30 had mild OSA, 35 with moderate to severe OSA)). Was there any other missing data? I missed any statements on further exclusions after the total of 111.

14. Lines 244-246. Please explain or rephrase. This sentence is confusing and has no clear meaning as it is written.

15. Table 5. why age > 58 years? How did you come about 58?? was there something in the data to suggest that 58 was an age that impacted having OSAHS or was it just based on the calculated mean age?

I believe age > 50 is what standard questionnaires use. Or if you want to look at teh geriatric population vs the other adults then maybe age of 65 and above etc. 58 appears random. Also, may be better to use "BMI>30" in the last row of the table rather than the term obesity.

16. Line 287: consider replacing "underline" with "depict"

17. Line 288 - 294: Starting from the sentence "Other studies..."These lines should follow line 284 for the sake of continuity.

18. Lines 285 - 288 ending with ref (14,26). should come after line 294. You may choose to say " Further more in our study....." to bring the readers attention back to the fact that you are referring to the findings from your study.

19. Line 303: Remove "a" before controlled hypertension, did you mean uncontrolled or controlled hypertension?

20. Line 313: The polysomnogram is not time consuming (takes the same amount of time as a portable study - in both cases overnight). More appropriate to say it is more expensive and requires more resources (skilled staff, sleep lab, equipment etc)

21. Line 317: Please replaced with AHI. and total recording time

22. Consider adding to discussion RE: results lines 179 - 180 state that ESS scores did not correlate with sleepiness. This is corroborated by several papers. Examples to look at include: 1. Smith et al . Multiple dimensions of excessive daytime sleepiness J Thorac Dis 2018, 2. Silva et al. identifiction of patients with sleep disordered breathing: comparing the four-variable screening tool... J Clin Sleep med 2011. etc. It may be nice to mention that your study finding corroborates the fact that the ESS should not be used in isolation to determine the presence of sleepiness.

23. Line 327 - 328 in conclusion: Amend to say "in patients with resistant/uncontrolled hypertension in hospital settings" . It is not cost effective or required in all hospitalized patients with hypertension. Patients with hypertension and risk factors for OSAHS can be studied in the outpatient setting.

Final comments: Overall a very good paper with excellent potential to publish regarding the OSA experience in Subsaharan Africa.

Reviewer #2: Interesting study, I commend the authors to undergo such an investigation in a country in which sleep services are not as developed as in other parts of the world.

Several comments and recommendations are listed here;

1. Have the ESS and STOP-BANG questionnaires been translated and validated in local languages? If so, how does one explain the major discrepancy between the prevalence of sleepiness (assessed qualitatively) and that of ESS>10 (Table 4)?

2. In the study flow diagram - you list 65 invalid PMD records; this is a high rate - one could want to see those repeated, so that power is not affected by the significantly lower sample size analyzed.

3. Abstract (results section) and manuscript: I would avoid causal inferences such as hypertension being the determinant of moderate to severe OSA... It may not be correct and you may not be able to prove it in a cross-sectional study. It is an association.

4. Abstract (conclusion) and manuscript: too strong a language ('is mandatory...') as a conclusion to this study's findings.

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Reviewer #1: No

Reviewer #2: No

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PONE-D-19-25768R1

Obstructive sleep apnea and hypopnea syndrome in patients admitted in a tertiary hospital in Cameroon: prevalence and associated factors

PLOS ONE

Dear Dr. Poka-Mayap,

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.

==============================

ACADEMIC EDITOR: Be sure to:

See below for one final edit.

==============================

We would appreciate receiving your revised manuscript by Feb 03 2020 11:59PM. When you are ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter.

To enhance the reproducibility of your results, we recommend that if applicable you deposit your laboratory protocols in protocols.io, where a protocol can be assigned its own identifier (DOI) such that it can be cited independently in the future. For instructions see: http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols

Please include the following items when submitting your revised manuscript:

• A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). This letter should be uploaded as separate file and labeled 'Response to Reviewers'.
• A marked-up copy of your manuscript that highlights changes made to the original version. This file should be uploaded as separate file and labeled 'Revised Manuscript with Track Changes'.
• An unmarked version of your revised paper without tracked changes. This file should be uploaded as separate file and labeled 'Manuscript'.

Please note while forming your response, if your article is accepted, you may have the opportunity to make the peer review history publicly available. The record will include editor decision letters (with reviews) and your responses to reviewer comments. If eligible, we will contact you to opt in or out.

We look forward to receiving your revised manuscript.

Kind regards,

James Andrew Rowley

Academic Editor

PLOS ONE

Additional Editor Comments (if provided):

As the academic editor, I reviewed the author's revisions based upon the reviewers' comments and find that they have responded in a satisfactory manner.

However, there is one wording change that I have found upon my review that needs changing before full acceptance. Line 336 in the version with the edits shown, the word 'weaker' is not correct. Portable monitoring devices yield a lower than expected AHI given the denominator is recording time and not sleep time but this does not make the AHI 'weaker'. Please word 'Furthermore, PMD yields a lower AHI compared to full polysomnography,' (Note also to take the 'O' out before 'AHI')

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While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email us at figures@plos.org. Please note that Supporting Information files do not need this step.

Obstructive sleep apnea and hypopnea syndrome in patients admitted in a tertiary hospital in Cameroon: prevalence and associated factors

PONE-D-19-25768R2

Dear Dr. Poka-Mayap,

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James Andrew Rowley

Academic Editor

PLOS ONE

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