night-to-night variability of respiratory events in

Supplementary Mater ial

Night-to-night variability of respiratory events in obstructive sleep apnoea: a systematic review and meta-analysis

Maurice Roeder MD1, Matteo Bradicich MD1, Thomas Gaisl MD1, Sira Thiel MD1, Esther I. Schwarz MD1,2 ,Ulrike

Held PhD3, Malcolm Kohler MD1,2

These supplementary tables, references, figures, and appendices have been provided by the authors to give readers

additional information about their work.

BMJ Publishing Group Limited (BMJ) disclaims all liability and responsibility arising from any relianceSupplemental material placed on this supplemental material which has been supplied by the author(s) Thorax

doi: 10.1136/thoraxjnl-2020-214544–8.:10 2020;Thorax, et al. Roeder M

Table of Contents

Methods

- Search Terms

- Studies obtained by handsearching

- Studies obtained by https://clinicaltrials.gov/

Study details and patient characteristics

- Study characteristics

- Inclusion criteria

- Exclusion criteria

- Patient characteristics

- Sleep study characteristics

Results

Quality Assessment

Guidelines

- MOOSE Guidelines for Meta-Analyses and Systematic Reviews of Observational Studies

- Prisma 2009 Checklist

References



https://clinicaltrials.gov/

Methods

Search terms

a) The following search terms were employed for PUBMED (https://www.ncbi.nlm.nih.gov/pubmed)

1. apnoea-hypopnoea index* or apnoea-hypopnoea indices or apnea-hypopnea index* or apnea-hypopnea

indices or AHI or oxygen-desaturation index* or oxygen-desaturation indices or ODI or obstructive apnea

index* or obstructive apnea indices or OAI or respiratory disturbance index* or respiratory disturbance

indices or RDI or apnoea index* or apnoea indices or apnea index* or apnea indices

2. “variabilit*”.ti,ab.

3. 1 AND 2

4. (night-to-night or first-night effect* or FNE or second-night effect*).ti,ab

5. 3 or 4

b) The following search terms were employed for Cochrane Library

1. “apnoea-hypopnoea index*" OR "apnoea-hypopnoea indices" OR "apnea-hypopnea index*" OR "apnea-

hypopnea indices" OR AHI OR "oxygen-desaturation index*" OR "oxygen-desaturation indices" OR ODI

OR "obstructive apnoea index*" OR "obstructive apnea indices" OR OAI OR "respiratory disturbance

index*" OR "respiratory disturbance indices" OR RDI OR "apnoea index*" OR "apnoea indices" OR "apnea

index*" OR "apnea

2. variabilit*:kw,ti,ab

3. #1 AND #2

4. ("night-to-night" OR "first-night effect*" OR FNE OR "second-night effect*")kw,ti,ab

5. #3 OR #4

c) The following search terms were employed for Embase

1. 'apnea hypopnea index'/exp OR 'oxygen desaturation index'/exp OR 'respiratory disturbance index'/exp OR

'apnoea-hypopnoea index*':ti,ab OR 'apnoea-hypopnoea indices':ti,ab OR 'apnea-hypopnea index*':ti,ab OR

'apnea-hypopnea indices':ti,ab OR ahi:ti,ab OR 'oxygen-desaturation index*':ti,ab OR 'oxygen-desaturation

indices':ti,ab OR odi:ti,ab OR 'obstructive apnea index*':ti,ab OR 'obstructive apnea indices':ti,ab OR

oai:ti,ab OR 'respiratory disturbance index*':ti,ab OR 'respiratory disturbance indices':ti,ab OR rdi:ti,ab OR

'apnoea index*':ti,ab OR 'apnoea indices':ti,ab OR 'apnea index*':ti,ab OR 'apnea indices':ti,ab

2. variabilit*:ti,ab

3. #1 AND #2

4. 'night-to-night':ti,ab OR 'first-night effect*':ti,ab OR fne:ti,ab OR 'second-night effect*':ti,ab

5. #3 OR #4



https://www.ncbi.nlm.nih.gov/pubmed

d) The following search terms were employed for ClinicalTrials.gov

1. “OSA” AND “variability”

Languages: English, German, French

Children: Yes, Animals: No, Timeframe: from the 23. January of 2019

Studies obtained by handsearching Author Title Journal Year DOI

Kapur, V. K. Clinical Practice Guideline for Diagnostic

Testing for Adult Obstructive Sleep Apnea: An

American Academy of Sleep Medicine Clinical

Practice Guideline

J Clin Sleep Med

2017

10.5664/jcsm.6506.

Table S 1 Studies obtained by handsearching.

Studies obtained by https://clinicaltrials.gov/ Author Title Year ClinicalTrials.gov Identifier

Kohler, M. Effect of Longitudinal Sleep Monitoring on Diagnosis and

Treatment Decision in Patients With Suspected Obstructive

Sleep Apnea (ELSA)

2018

NCT03819361

Table S 2 Studies obtained by https://clinicaltrials.gov/.





Study details and patient characteristics

Study characteristics

Authors Study Design Multicentric Participants Analysed

Patients

OSA already

diagnosed Comorbidities

Aarab et al.1 RCT No 17 15 Yes None

Ahmadi et al.2 Retrospective No 193 193 No None

Bittencourt et al.3 Prospective No 20 20 Yes None

Bliwise et al.4 Prospective Yes 71 71 No None

Büttner et al.5 Prospective No 100 100 Yes None

Davidson et al.6 Prospective No 44 44 No None

Fietze et al.7 Prospective No 35 35 No None

Gouveris et al.8 Retrospective No 130 130 No Upper airway

pathology

Joosten et al.9 Prospective No 75 44 No None

Laing et al.10 Prospective No 30 19 No None

Le Bon et al.11 Retrospective Yes 243 169 No None

Levendowski et al.12 RCT Yes 118 20 No None

Mendelson et al.13 Prospective No 50 No None

Meyer et al.14 Prospective No 11 11 No None

Mjid et al.15 Prospective No 20 20 No None

Newell et al.16 Retrospective No 118 44 No None

Prasad et al.17 Prospective No 398 84 Yes None

Quan et al.18 Retrospective Yes 99 91 Yes None

Selwa et al.19 Prospective Yes 43 40 No Epilepsy

Stepnowsky et al.20 Retrospective No 1220 1091 No None

Stöberl et al.21 Retrospective Yes 109 77 Yes None

White et al.22 Prospective No 26 26 Yes None

Wittig et al.23 Retrospective No 50 22 Yes None

Yalciner et al.24 Prospective No 30 30 No None

Table S 3 Characteristics of the studies included in the meta-analysis. RCT: Randomised Controlled Trial.



Inclusion criteria

Authors Inclusion Criteria

Aarab et al.1 Age > 18, AHI 5-45.

Ahmadi et al.2 2 PSGs with available AHI.

Bittencourt et al.3 Age 30-60, AHI > 10 events, laboratory exams (blood cell count, glycaemia, creatinine, T3, T4, and TSH),

spirometry, thoracic radiography, and ECG within normal values.

Bliwise et al.4 None.

Büttner et al.5 Age 18-80, SDB with AHI >5.

Davidson et al.6 Patients with SDB symptoms (primarily snoring), recommended and approved for sleep testing.

Fietze et al.7 Expected OSA with ESS >10 or other two major OSAS symptoms.

Gouveris et al.8 Patients with suspected OSA with 2 PSGs, with upper airway pathology as the sole possible cause of sleep-

related breathing disorder.

Joosten et al.9

Patients with suspected OSA. Inclusion only if, after PSG:

-OSA (AHI>5/h) on both nights

- ≥30 min supine, ≥20 min non-supine in both nights.

Laing et al.10 ESS>10. Symptoms suggesting OSA (observed sleep aponeas, snoring on a regular basis).

Le Bon et al.11 Patients with suspected sleep apnoea free of psychotropic medications for the two weeks prior to PSG.

Levendowski et al.12 AHI 10-40, BMI <40, no OSA treatment, non-smoker, ESS >10, postmenopausal.

Mendelson et al.13 Patients with suspected sleep apnoea.

Meyer et al.14 Adult patients at increased risk for OSA (one or more of the following: history of witnessed apnoeas; presence

of hypertension (DBP>=95 mmHg or history of treated hypertension); increased BMI (>30)).

Mjid et al.15 Clinical suspect of OSAS.

Newell et al.16 Two sleep studies. AHI>5 in the first sleep study.

Prasad et al.17 Age 35-60, AHI >5 at baseline PSG.

Quan et al.18 Participant in Sleep Heart Health Study, willing to perform two PSGs within 4 months after the first one.

Selwa et al.19 Two or more seizures per month (generalised or partial, auras excluded) in medical history. High suspicion

for OSA.

Stepnowsky et al.20 Patients with suspected sleep apnoea referred for sleep apnoea testing.

Stöberl et al.21 Age 20-75, OSA patients (ODI>10 / ODI>20) and CPAP therapy, recurrence of OSA after 4 days of

withdrawal.

White et al.22 Clinical suspicion of sleep apnoea and OSA confirmed.

Wittig et al.23 At least 2 PSG within 30 days, no weight changes > 10 pounds, no change in medication, and no intervening

treatment.

Yalciner et al.24 Signs and symptoms of SDB.

Table S 4 Inclusion criteria of the studies included in the meta-analysis. AHI: apnoea-hypopnoea index. PSG:

polysomnography. T3: triiodothyronine. T4: thyroxin. TSH: thyroid-stimulating hormone. ECG:

electrocardiogram. SDB: sleep-disordered breathing. OSA(S): obstructive sleep apnoea (syndrome). ESS:

Epworth Sleepiness Scale. DBP: diastolic blood pressure. BMI: body mass index. ODI: oxygen desaturation index.

CPAP: continuous positive airway pressure.



Exclusion criteria

Authors Exclusion Criteria

Aarab et al.1

Respiratory or sleep disorder other than OSA. BMI >40. Medication usage that could affect respiration or sleep.

Periodic limb movement disorder. Previous treatment with CPAP or MAD. Reversible morphological upper

airway abnormalities. Temporomandibular disorders. Untreated periodontal problems. Dental pain. Lack of

retention possibilities for mandibular advancement device or placebo appliance.

Ahmadi et al.2 NR

Bittencourt et al.3 Diseases that might result in sleep alterations, habits, or occupations that might lead to sleep deprivation or altered

sleep-wake cycle, infection of the upper or lower airways, altered ENT evaluation.

Bliwise et al.4 Alcohol or psychoactive medications.

Büttner et al.5 Other sleep disorders or disorders that might affect either sleep or oxygenation. Psychiatric diseases. Drug abuse.

Sleep therapy within 12 months. Reduced CPAP compliance.

Davidson et al.6 Minors, pregnancy, dementia.

Fietze et al.7 Alcohol consumption.

Gouveris et al.8

Patients suspected of suffering from isolated or concomitant to the upper airway pathology narcolepsy,

hypersomnolence, chronic fatigue syndrome, periodic limb movement disorder, and/or diurnal rhythm disorders

as well as patients with an established diagnosis of a psychiatric or neurologic (peripheral or central) disorder.

Congestive heart failure, COPD or any severe pulmonary disorder requiring standard medication.

Joosten et al.9 No informed consent. Domicile more than 75 km from study centre.

Laing et al.10 COPD (FEV1<70% predicted). Heart failure (Eco EF < 30%). Systemic disease. Malignancy. Neurologic

disorders.

Le Bon et al.11 None.

Levendowski et al.12 NR

Mendelson et al.13 Any medication supressing respiration.

Meyer et al.14 Prior oxygen therapy, CPAP therapy, or other medical therapy for OSA.

Mjid et al.15 Major psychiatric disorders, sleep depriving-activities, lower airways-respiratory infection within 30 days.

Newell et al.16

CPAP trial in the second sleep study. Comorbid affective disorders (anxiety and depression), neurological

disorders, PLMI>=5 for one or both recordings, daily consumption of more than two units of alcohol. Patient

referred for MSLT test.

Prasad et al.17 Diagnosis of another sleep disorder diagnosed either on PSG or by history, previous treatment of OSA, pregnancy.

Quan et al.18 CPAP or mandibular device, oxygen therapy, tracheotomy.

Selwa et al.19 Seizures in at least one of the study nights.

Stepnowsky et al.20 Supplemental oxygen or CPAP.

Stöberl et al.21 Ventilatory failure, Cheyne-Stokes respiration, unstable or untreated cardiovascular disease or uncontrolled

hypertension, and professional drivers or patients with a history of a traffic accident.

White et al.22 OSA treated within the last 3 months, tonsillar hypertrophy, heart failure, stroke, and end-stage renal or liver

disease.

Wittig et al.23 NR

Yalciner et al.24 Severe comorbidities. Upper airway infection in the previous two weeks. Sedative medication use or alcohol

addiction. Previous trial of CPAP or MAD.

Table S 5 Exclusion criteria of the studies included in the meta-analysis. OSA: obstructive sleep apnoea. BMI:

body mass index. CPAP: continuous positive airway pressure. MAD: mandibular advancement device. ENT: ear, nose, and throat. COPD: chronic obstructive pulmonary disease. FEV1: forced expiratory volume in the first

second. EF: ejection fraction. NR: not reported. PLMI: periodic limb movement index. MSLT: multiple sleep

latency test. PSG: polysomnography.



Patient characteristics

Authors Male Female Average Age Average BMI Average ESS

Aarab et al.1 13 4 50.8 30.1 11.2

Ahmadi et al.2 NR NR NR NR NR

Bittencourt et al.3 14 6 50 30 16

Bliwise et al.4 48 23 74.6 34.92 NR

Büttner et al.5 83 17 53.3 30.9 10.2

Davidson et al.6 NR NR 48 30.1 NR

Fietze et al.7 32 3 58 26 NR

Gouveris et al.8 86.1 13.9 52.6 NR NR

Joosten et al.9 24 20 50.3 30.5 8.3

Laing et al.10 12 7 51.6 29 NR

Le Bon et al.11 113 56 47.2 27.4 NR

Levendowski et al.12 17 3 NR NR NR

Mendelson et al.13 42 8 50.2 NR NR

Meyer et al.14 8 3 44.91 28.85 NR

Mjid et al.15 7 13 50.6 36.3 NR

Newell et al.16 29 15 52.16 30.85 9.77

Prasad et al.17 56 28 47 38.3 12

Quan et al.18 55 44 64.2 28.31 NR

Selwa et al.19 19 21 40.2 32.4 NR

Stepnowsky et al.20 947 144 52.5 33 10.7

Stöberl et al.21 65 12 62.6 33.8 14

White et al.22 16 10 57.2 32.1 NR

Wittig et al.23 22 0 49.7 NR NR

Yalciner et al.24 17 13 42.1 30.2 14

Table S 6 Cohort characteristics of the studies included in the meta-analysis. BMI: body mass index. ESS:

Epworth Sleepiness Scale. NR: not reported.



Authors Population Information and Study Nation

Aarab et al.1 Netherlands.

Ahmadi et al.2

Inpatients at the Toronto Western

Hospital Sleep and Alertness Clinic over the period of

1 year. Canada.

Bittencourt et al.3 Twenty patients referred from the Respiratory Sleep Disorders outpatient clinic (Respiratory

Division). Brazil.

Bliwise et al.4 Volunteers from a cohort study of sleep and breathing. USA.

Büttner et al.5 Germany.

Davidson et al.6 Patients referred for SDB symptoms (primarily snoring). USA.

Fietze et al.7

All study patients have been referred to the sleep centre with possible OSAHS, and had

experienced either self-reported daytime sleepiness (ESS >10) or two other major symptoms of

OSAHS. Symptomatic mild-to-moderate OSAHS patients. Germany.

Gouveris et al.8 Patients suspected of OSA with upper airway pathology as the sole possible cause of sleep-

related breathing disorder. Germany.

Joosten et al.9 Database of OSA referrals waiting for PSG.

Australia.

Laing et al.10 Germany.

Le Bon et al.11 94% comes from immediate surroundings of Brussels with suspected sleep apnoea. Belgium.

Levendowski et al.12 Australia.

Mendelson et al.13 Self-admitted to the sleep disorders Center of the State University of New York. USA.

Meyer et al.14 USA.

Mjid et al.15 Referral for clinical suspicion of OSAS. Tunisia.

Newell et al.16

Referred to the sleep laboratory and diagnosed for snoring or UARS as well as central, mixed,

and obstructive hypopneas or apnoeas.

All patients were free from neuropsychopharmacological treatment, including hypnotics and

antidepressants, for at least two weeks prior to recording. Daytime napping was not allowed in

the sleep unit. Patients that were addressed for multiple sleep latency tests (MSLT) were

excluded from the study since these daytime assessments can potentially influence the following

night's sleep recording

Prasad et al.17 Referrals for possible OSA. USA.

Quan et al.18 Participant in Sleep Heart Health Study. USA.

Selwa et al.19 High suspicion for OSA and quantifiable seizures. USA.

Stepnowsky et al.20 Referrals for suspected OSA. USA.

Stöberl et al.21 Patients under CPAP withdrawal with OSA recurrence after withdrawal. Switzerland, UK.

White et al.22 Referred to sleep centre for clinical suspicion. Canada.

Wittig et al.23 Adult, male patients. USA.

Yalciner et al.24 Referrals to ENT specialist. Turkey.

Table S 7 Population and geographical information of the studies included in the meta-analysis. SDB: sleep-

disordered breathing. OSA: obstructive sleep apnoea. OSA(H)S: obstructive sleep apnoea(-hypopnoea) syndrome.

ESS: Epworth Sleepiness Scale. PSG: polysomnography. UARS: upper airway resistance syndrome. MSLT:

multiple sleep latency test. ENT: ear, nose, and throat.



Sleep study characteristics

Authors Sleep study Recording device Montage by Number

of studies

Max days

between

studies

Number of

examiners

Aarab et al.1 Home PSG Monet hardware, Rembrandt software (Medcare

Automation BV). Technician 4 23.1 1

Ahmadi et al.2 In-hospital

PSG NR Technician 2 1 NR

Bittencourt et al.3 In-hospital

PSG

Sleep Analyzer Computer (SAC system 9.3,

Oxford Instruments, Abingdon, UK). Technician 4 1 1

Bliwise et al.4 In-hospital

PSG NR Technician 2 1 1

Büttner et al.5 In-hospital


Davidson et al.6 HSAT Embletta (AutoSet Portable H Plus). Patient 3 1 0

Fietze et al.7 HSAT MESAM-IV. Technician 7 1 1

Gouveris et al.8 In-hospital

PSG Alice 4. Technician 2 1 2

Joosten et al.9 In-hospital

PSG Compumedics E-Series. Technician 2 4 1

Laing et al.10 HSAT Jaeger Pro, Fa ViaSys, Wuerzburg Patient 3 1 1

Le Bon et al.11 In-hospital

PSG Alice Respironics; Plattsburgh, PA. Technician 2 1 2

Levendowski et al.12 In-hospital

PSG

Alice 4-Respironics Inc. and Compumedics E-

series. Technician 2 40 1

Mendelson et al.13 In-hospital


Meyer et al.14 In-hospital

PSG NR Technician 2 54.1 NR

Mjid et al.15 In-hospital

RP CIDELEC 102 L. Technician 2 1 NR

Newell et al.16 PSG Alice 5. Technician 2 1 2

Prasad et al.17 HSAT +

Actigraphy

EmblettaTM PDS system (Natus Neurology

Inc., Middleton, WI). Technician 8 1 1

Quan et al.18 Home PSG Compumedics PS-2 series - Compumedics Pty.

Ltd, Abbotsville, AU. Technician 2 77 >1

Selwa et al.19 In-hospital

PSG NR Technician 2 1 2

Stepnowsky et al.20 HSAT NovaSom QSG™ (Sleep Solutions, Inc.). Technician 3 1 0

Stöberl et al.21 Pulse

oximetry

Pulse oximeter (Pulsox-300i, Konica Minolta

Sensing Inc, Osaka, Japan) or ResLink (ResMed

Corp, San Diego, CA, USA).

Patient 13 1 NR

White et al.22 In-hospital

PSG Sandman (Nellcor). Technician 2 18.7 1

Wittig et al.23 In-hospital


Yalciner et al.24 In-hospital

PSG Philips Respironics. Technician 2 7 NR

Table S 8 Sleep study characteristics. PSG: polysomnography. NR: not reported. HSAT: home sleep apnoea

testing. RP: respiratory polygraphy.



Results

Figure S1: Sensitivity analysis of mean change in AHI between first and second night, by excluding studies with

high risk of bias. Kendall's tau = -0.2308, p = 0.2792. AHI=apnoea-hypopnoea index, HSAT=home sleep apnoea

testing, N=number of analysed patients, PSG=polysomnography, P=prospective study design, Q=Cochrane’s Q test, R=retrospective study design, RE=random effect model, RP=respiratory polygraphy, Y=year.



Figure S 2 Forest plot of mean AHI change between the 1st and the 2nd night in in-hospital sleep studies. Kendall's

tau = 0.000, p = 1.000. RE=random effect.



Figure S 3 Forest plot of mean AHI change between the 1st and the 2nd night in in-home sleep studies. Kendall's

tau = 0.0000, p = 1.0000. RE=random effect.



Figure S 4 Forest plot of the proportion of patients who changed severity class in one of the sequential

measurement nights. Kendall's tau = 0.067, p = 1.000. HSAT=home sleep apnoea testing N=number of analysed

patients, PSG=polysomnography, P=prospective study design, Q=Cochrane’s Q test, R=retrospective study design,

RE=random effect, RP=respiratory polygraphy, Y=year.



Figure S 5 a Proportions of patients who have changed into a lighter OSA severity class after the first sleep study. Kendall's tau = 0.143, p = 0.697. HSAT=home sleep apnoea testing, N=number of analysed patients,

PSG=polysomnography, P=prospective study design, Q=Cochrane’s Q test, R=retrospective study design, RE=random effect, RP=respiratory polygraphy, Y=year.



Figure S5 b Proportions of patients who have changed into a more severe class after the first sleep study.

Kendall's tau = -0.333, p = 0.469. HSAT=home sleep apnoea testing, N=number of analysed patients,

PSG=polysomnography, P=prospective study design, Q=Cochrane’s Q test, R=retrospective study design, RE=random effect, RP=respiratory polygraphy, Y=year.



Quality Assessment

Item 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Overall bias

assessment

Aarab et al. Yes Yes Yes Yes No Yes Yes Yes Yes No Yes Yes Yes Yes Low

Ahmadi et al. Yes No Yes Yes No No Yes Yes NR No Yes NR NA No Moderate

Bittencourt et al. Yes Yes Yes Yes No Yes Yes Yes Yes No Yes Yes Yes No Low

Bliwise et al. Yes Yes Yes Yes No CD Yes Yes Yes Yes No NR Yes No Moderate

Büttner et al. Yes Yes CD Yes No Yes Yes Yes Yes No Yes NR Yes No Low

Davidson et al. Yes No Yes Yes No Yes Yes Yes Yes No Yes Yes Yes Yes Moderate

Fietze et al. Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes Yes Low

Gouveris et al. Yes No Yes Yes No No Yes Yes NR Yes Yes NR NA No Moderate

Joosten et al. Yes Yes Yes Yes No Yes Yes Yes Yes No Yes NR Yes Yes Low

Laing et al. Yes Yes CD Yes No Yes Yes Yes** Yes Yes Yes NR Yes Yes Low

Le Bon et al. Yes Yes Yes Yes No No Yes Yes Yes No Yes NR NA Yes Moderate

Levendowski et al. Yes No No Yes No Yes Yes Yes Yes No Yes Yes Yes No High

Mendelson et al. Yes No Yes Yes No Yes Yes Yes Yes No Yes NR Yes No Moderate

Meyer et al. Yes Yes NR Yes No Yes Yes Yes NR No Yes NR Yes No Moderate

Mjid et al. Yes Yes Yes Yes No Yes Yes Yes NR Yes Yes NR Yes Yes Low

Newell et al. Yes Yes No Yes No No Yes Yes Yes No Yes NR NA No High

Prasad et al. Yes Yes No Yes No Yes Yes Yes Yes Yes Yes NR No Yes Moderate

Quan et al. Yes Yes No Yes Yes Yes Yes Yes Yes No Yes Yes Yes Yes Moderate

Selwa et al. Yes Yes Yes Yes No Yes Yes Yes Yes No Yes Yes Yes No Low

Stepnowsky et al. Yes Yes Yes Yes No No Yes Yes NR No Yes NR NA No Moderate

Stöberl et al. Yes Yes No Yes No No Yes Yes* Yes No Yes Yes NA Yes Moderate

White et al. Yes Yes No Yes No No Yes Yes Yes Yes Yes Yes NA No Moderate

Wittig et al. Yes No No No No No Yes Yes NR No Yes NR NA No High

Yalciner et al. Yes Yes Yes Yes No Yes Yes Yes Yes No Yes NR Yes Yes Low

Table S 9 Risk of bias analysis of the included studies, evaluated using the study assessment tool from NIH “Quality of Observational Cohort and Cross-Sectional Studies”. CD=cannot determine; NR=not reported; NA=not applicable; *:

only data on ODI reported.



Fourteen items for bias assessment adapted for this meta-analysis.

1. Was the research question or objective in this paper clearly stated?

2. Was the study population clearly specified and defined?

3. Was the participation rate of eligible persons at least 50%?

4. Were all the subjects selected or recruited from the same or similar populations (including the same period of

time)? Were inclusion and exclusion criteria for being in the study prespecified and applied uniformly to all

participants?

5. Was a sample size justification, power description, or variance and effect estimates provided? 6. Was the study a prospective study with predefined inclusion criteria?

7. Was the timeframe sufficient so that one could reasonably expect to see an association between exposure and

outcome if it existed? (i.e. more than 2 nights)

8. For exposures that can vary in amount or level, did the study examine different levels of the exposure as related

to the outcome (e.g., did the study also measure ODI or other sleep-related disturbance markers)?

9. Were the exposure measures (independent variables) clearly defined, valid, reliable, and implemented

consistently across all study participants (e.g. did the study use predefined guidelines such as AASM etc.)?

10. Was the outcome assessed in different ways (e.g. did the study also report ODI, SpO2 levels etc.)?

11. Were the outcome measures clearly defined, valid, reliable, and implemented consistently across all study

participants?

12. Were the outcome assessors blinded to the exposure status of participants? 13. Was loss to follow-up after baseline 20% or less?

14. Were key potential confounding variables measured and statistically adjusted for their impact on the relationship

between outcome(s) (e.g. regression analysis)?

Note: Boxes indicate a “significant” item deemed by the authors, affecting the overall bias assessment.

Overall bias assessment was categorized into three ratings

Low 0-2 items with risk factors & no items deemed “significant” by the authors

Moderate 3-4 items with risk factors & max. 1 item deemed “significant” by the authors High >4 items with risk factors and more than 1 “significant” item deemed by the authors



Guidelines

MOOSE Guidelines for Meta-Analyses and Systematic Reviews of Observational Studies*

Topic Availabe in

Section…

Title Identify the study as a meta-analysis (or systematic review) Title

Abstract Use the journal’s structured format Abstract

Introduction Present:

The clinical problem Introduction

The hypothesis Introduction

A statement of objectives that includes the study population, the condition of interest, the exposure or

intervention, and the outcome(s) considered

Introduction

Sources Describe:

Qualifications of searchers (eg, librarians and investigators) Methods

Search strategy, including time period included in the synthesis and keywords Methods

Effort to include all available studies, including contact with authors Methods

Databases and registries searched Methods

Search software used, name and version, including special features used

(e.g. explosion)

Methods

Use of hand searching (e.g, reference lists of obtained articles) Methods

List of citations located and those excluded, including justification Methods

Method of addressing articles published in languages other than English Methods

Method of handling abstracts and unpublished studies Methods

Description of any contact with authors Methods

Study

Selection

Describe

Types of study designs considered Methods

Relevance or appropriateness of studies gathered for assessing the hypothesis to be tested Methods

Rationale for the selection and coding of data (eg, sound clinical principles or convenience) Methods

Documentation of how data were classified and coded (eg, multiple raters, blinding,

and inter-rater reliability)

Methods

Assessment of confounding (e.g. comparability of cases and controls in

studies where appropriate)

NA

Assessment of study quality, including blinding of quality assessors;

stratification or regression on possible predictors of study results

Methods

Assessment of heterogeneity Methods

Statistical methods (eg, complete description of fixed or random effects models, justification of

whether the chosen models account for predictors of study results, dose-response models, or

cumulative meta-analysis) in sufficient detail to be replicated

Methods



Results Present

A graph summarizing individual study estimates and the overall estimate Results

A table giving descriptive information for each included study Results

Results of sensitivity testing (eg, subgroup analysis) Results

Indication of statistical uncertainty of findings Results

Discussion Discuss

Strengths and weaknesses Discussion

Potential biases in the review process (eg, publication bias) Discussion

Assessment of quality of included studies Results

Consideration of alternative explanations for observed results Discussion

Generalization of the conclusions (ie, appropriate for the data presented and within the domain of the

literature review)

Discussion

Guidelines for future research Discussion

Disclosure of funding source Methods

*Modified from Stroup DF, Berlin JA, Morton SC, Olkin I, Williamson GD, Rennie D, et al. Meta-analysis of

observational studies in8 epidemiology: a proposal for reporting. Meta-analysis Of Observational Studies in

Epidemiology (MOOSE) group. JAMA 2000;283:2008–12. Copyrighted © 2000, American Medical Association.

All rights reserved.



21

Prisma 2009 Checklist

Section/topic # Checklist item Reported in

section

TITLE

Title 1 Identify the report as a systematic review, meta-analysis, or both. Title

ABSTRACT

Structured summary 2 Provide a structured summary including, as applicable: background;

objectives; data sources; study eligibility criteria, participants, and

interventions; study appraisal and synthesis methods; results;

limitations; conclusions and implications of key findings; systematic

review registration number.

Abstract

INTRODUCTION

Rationale 3 Describe the rationale for the review in the context of what is already

known.

Introduction

Objectives 4 Provide an explicit statement of questions being addressed with

reference to participants, interventions, comparisons, outcomes, and

study design (PICOS).

Introduction

METHODS

Protocol and registration 5 Indicate if a review protocol exists, if and where it can be accessed

(e.g. Web address), and, if available, provide registration information

including registration number.

Methods

Eligibility criteria 6 Specify study characteristics (e.g. PICOS, length, of follow-up) and

report characteristics (e.g. years considered, language, publication

status) used as criteria for eligibility, giving rationale.

Methods

Information sources 7 Describe all information sources (e.g. databases with dates of

coverage, contact with study authors to identify additional studies) in

the search and date last searched.

Methods

Search 8 Present full electronic search strategy for at least one database,

including any limits used, such that it could be repeated.

Appendix

Study selection 9 State the process for selecting studies (i.e. screening, eligibility,

included in systematic review, and, if applicable, included in the

meta-analysis).

Methods

Data collection process 10 Describe method of data extraction from reports (e.g. piloted forms,

independently, in duplicate) and any processes for obtaining and

confirming data from investigators.

Methods

Data items 11 List and define all variables for which data were sought (e.g. PICOS,

funding sources) and any assumptions and simplifications made.

Methods

Risk of bias in individual studies 12 Describe methods used for assessing risk of bias of individual studies

(including specification of whether this was done at the study or

outcome level), and how this information is to be used in any data

synthesis.

Methods

Summary measures 13 State the principal summary measures (e.g. risk ratio, difference in

means).

Methods

Synthesis of results 14 Describe the methods of handling data and combining results of

studies, if done, including measures of consistency (e.g. I2 for each

meta-analysis).

Methods



22

Section/topic # Checklist item Reported in

section

Risk of bias across studies 15 Specify any assessment of risk of bias that may affect the cumulative

evidence (e.g. publication bias, selective reporting within studies).

Methods

Additional analyses 16 Describe methods of additional analyses (e.g. sensitivity or subgroup

analyses, meta-regression), if done, indicating which were pre-

specified.

Methods

RESULTS

Study selection 17 Give numbers of studies screened, assessed for eligibility, and

included in the review, with reasons for exclusions at each stage,

ideally with a flow diagram.

Results

Study characteristics 18 For each study, present characteristics for which data were extracted

(e.g. study size, PICOS, follow-up period) and provide the citations.

Appendix

Risk of bias within studies 19 Present data on risk of bias of each study and, if available, any

outcome level assessment (see item 12).

Appendix

Results of individual studies 20 For all outcomes considered (benefits or harms), present, for each

study: (a) simple summary data for each intervention group (b) effect

estimates and confidence intervals, ideally with a forest plot.

Results, Appendix

Synthesis of results 21 Present results of each meta-analysis done, including confidence

intervals and measures of consistency.

Results, Appendix

Risk of bias across studies 22 Present results of any assessment of risk of bias across studies (see

Item 15).

Appendix

Additional analysis 23 Give results of additional analyses, if done (e.g. sensitivity or

subgroup analyses, meta-regression [see Item 16]).

Results, Appendix

DISCUSSION

Summary of evidence 24 Summarise the main findings including the strength of evidence for

each main outcome; consider their relevance to key groups (e.g.

healthcare providers, users, and policy makers).

Discussion

Limitations 25 Discuss limitations at study and outcome level (e.g. risk of bias), and

at review level (e.g. incomplete retrieval of identified research,

reporting bias).

Discussion,

Limitations

Conclusions 26 Provide a general interpretation of the results in the context of other

evidence, and implications for future research.

Discussion

FUNDING

Funding 27 Describe sources of funding for the systematic review and other

support (e.g. supply of data) and role of funders for the systematic

review.

Methods

Table S 10 Prisma check list.

From: Moher D, Liberati A, Tetzlaff J, Altman DG, The PRISMA Group (2009). Preferred Reporting Items for

Systematic Reviews and Meta-Analyses: The PRISMA Statement. PLoS Med 6(6): e1000097.

doi:10.1371/journal.pmed1000097



23

References

1. Aarab G, Lobbezoo F, Hamburger HL, Naeije M. Variability in the apnea-hypopnea index and its

consequences for diagnosis and therapy evaluation. Respiration 2009; 77(1): 32-7.

2. Ahmadi N, Shapiro GK, Chung SA, Shapiro CM. Clinical diagnosis of sleep apnea based on single night

of polysomnography vs. two nights of polysomnography. Sleep Breath 2009; 13(3): 221-6.

3. Bittencourt LR, Suchecki D, Tufik S, et al. The variability of the apnoea-hypopnoea index. J Sleep Res

2001; 10(3): 245-51.

4. Bliwise DL, Benkert RE, Ingham RH. Factors associated with nightly variability in sleep-disordered

breathing in the elderly. Chest 1991; 100(4): 973-6.

5. Büttner A. Erste-Nacht-Effekt bei schlafbezogenen Atmungsstörungen. Nervenheilkunde 2008; 27(07):

659-63.

6. Davidson TM, Gehrman P, Ferreyra H. Lack of night-to-night variability of sleep-disordered breathing

measured during home monitoring. Ear Nose Throat J 2003; 82(2): 135-8.

7. Fietze I, Dingli K, Diefenbach K, et al. Night-to-night variation of the oxygen desaturation index in sleep

apnoea syndrome. Eur Respir J 2004; 24(6): 987-93.

8. Gouveris H, Selivanova O, Bausmer U, Goepel B, Mann W. First-night-effect on polysomnographic

respiratory sleep parameters in patients with sleep-disordered breathing and upper airway pathology. Eur Arch

Otorhinolaryngol 2010; 267(9): 1449-53.

9. Joosten SA, O'Donoghue FJ, Rochford PD, et al. Night-to-night repeatability of supine-related obstructive

sleep apnea. Ann Am Thorac Soc 2014; 11(5): 761-9.

10. Laing U, Fichter J. [Screening measurements for sleep apnea: is a single measurement enough?].

Pneumologie 2002; 56(11): 673-8.

11. Le Bon O, Hoffmann G, Tecco J, et al. Mild to moderate sleep respiratory events: one negative night may

not be enough. Chest 2000; 118(2): 353-9.

12. Levendowski DJ, Zack N, Rao S, et al. Assessment of the test-retest reliability of laboratory

polysomnography. Sleep Breath 2009; 13(2): 163-7.

13. Mendelson WB. Use of the sleep laboratory in suspected sleep apnea syndrome: is one night enough?

Cleve Clin J Med 1994; 61(4): 299-303.



24

14. Meyer TJ, Eveloff SE, Kline LR, Millman RP. One negative polysomnogram does not exclude obstructive

sleep apnea. Chest 1993; 103(3): 756-60.

15. Mjid M, Ouahchi Y, Toujani S, et al. [Night-to-night variability of the obstructive sleep apnoea-

hypopnoea syndrome]. Rev Mal Respir 2016; 33(9): 775-80.

16. Newell J, Mairesse O, Verbanck P, Neu D. Is a one-night stay in the lab really enough to conclude? First-

night effect and night-to-night variability in polysomnographic recordings among different clinical population

samples. Psychiatry Res 2012; 200(2-3): 795-801.

17. Prasad B, Usmani S, Steffen AD, et al. Short-Term Variability in Apnea-Hypopnea Index during

Extended Home Portable Monitoring. J Clin Sleep Med 2016; 12(6): 855-63.

18. Quan SF, Griswold ME, Iber C, et al. Short-term variability of respiration and sleep during unattended

nonlaboratory polysomnography--the Sleep Heart Health Study. [corrected]. Sleep 2002; 25(8): 843-9.

19. Selwa LM, Marzec ML, Chervin RD, et al. Sleep staging and respiratory events in refractory epilepsy

patients: Is there a first night effect? Epilepsia 2008; 49(12): 2063-8.

20. Stepnowsky CJ, Jr., Orr WC, Davidson TM. Nightly variability of sleep-disordered breathing measured

over 3 nights. Otolaryngol Head Neck Surg 2004; 131(6): 837-43.

21. Stoberl AS, Schwarz EI, Haile SR, et al. Night-to-night variability of obstructive sleep apnea. J Sleep Res

2017; 26(6): 782-8.

22. White LH, Lyons OD, Yadollahi A, Ryan CM, Bradley TD. Night-to-night variability in obstructive sleep

apnea severity: relationship to overnight rostral fluid shift. J Clin Sleep Med 2015; 11(2): 149-56.

23. Wittig RM, Romaker A, Zorick FJ, Roehrs TA, Conway WA, Roth T. Night-to-night consistency of

apneas during sleep. Am Rev Respir Dis 1984; 129(2): 244-6.

24. Yalciner G, Babademez MA, Gul F. Association of sleep time in supine position with apnea-hypopnea

index as evidenced by successive polysomnography. Sleep Breath 2017; 21(2): 289-94.



night-to-night variability of respiratory events in

Documents