Usefulness of obstructive sleep apnea-18 as a predictor of moderate-to-severe obstructive sleep apnea in children who have normal/inconclusive McGill oximetry score

Supakanya Tansriratanawong; Suchada Sritippayawan; Montida Veeravigrom; Jitladda Deerojanawong

doi:10.4103/prcm.prcm_14_19

ORIGINAL ARTICLE

Year : 2019 | Volume : 3 | Issue : 3 | Page : 60-64

Usefulness of obstructive sleep apnea-18 as a predictor of moderate-to-severe obstructive sleep apnea in children who have normal/inconclusive McGill oximetry score

Supakanya Tansriratanawong¹, Suchada Sritippayawan¹, Montida Veeravigrom², Jitladda Deerojanawong¹
¹ Department of Pediatrics, Division of Pulmonology and Critical Care, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
² Department of Pediatrics, Division of Neurology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand

Date of Submission	23-Sep-2019
Date of Decision	13-May-2020
Date of Acceptance	09-Jun-2020
Date of Web Publication	18-Aug-2020

Correspondence Address:
Suchada Sritippayawan
Department of Pediatrics, Division of Pulmonology and Critical Care, Faculty of Medicine, Chulalongkorn University, Rama IV Road,Bangkok 10330
Thailand

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/prcm.prcm_14_19

Abstract

Context: Overnight oximetry is a screening test for pediatric obstructive sleep apnea (OSA). However, those who demonstrate normal/inconclusive test still require diagnostic polysomnography (PSG). Since PSG has a long waiting list, an adjunct simple test for the prioritization would be helpful. Aims: The aim of this study is to determine whether the OSA-18 quality of life (QoL) questionnaire could predict moderate-to-severe OSA in children with normal/inconclusive overnight oximetry. Settings and Design: The study involves a cross-sectional study at a university hospital. Subjects and Methods: Overnight PSG and QoL assessed by the Thai-Version OSA-18 were performed in snoring children with normal/inconclusive overnight oximetry. Statistical Analysis: Unpaired Student's t-test, Chi-square, and receiver operating characteristic curve analysis were used. Results: A total of 218 children (age 6.4 ± 2.5 years, 62% male) were studied. Sixty percent had moderate-to-severe OSA, while 40% had primary snoring/mild OSA. The mean total OSA-18 score was not different between the two groups. Subgroup analysis among those who never had medical treatment for OSA (n = 55) showed a higher total OSA-18 score in moderate-to-severe compared to primary snoring/mild OSA groups (80.5 ± 10.7 vs. 72.2 ± 14.4; P = 0.02). Total OSA-18 score >78 was the best cutoff value for predicting moderate-to-severe OSA (61.5% sensitivity, 80% specificity, 72.7% positive predictive value, and 69.7% negative predictive value). Combining this cutoff value with overweight/obesity did not improve its predictivity. Conclusions: We found the association between high total OSA-18 score and moderate-to-severe OSA in snoring children who had normal/inconclusive overnight oximetry and never had medical treatment for OSA. However, the best cutoff value of the score and other potential add-on parameters are still needed to be investigated.

Keywords: Children, obstructive sleep apnea, obstructive sleep apnea-18, oximetry

How to cite this article:
Tansriratanawong S, Sritippayawan S, Veeravigrom M, Deerojanawong J. Usefulness of obstructive sleep apnea-18 as a predictor of moderate-to-severe obstructive sleep apnea in children who have normal/inconclusive McGill oximetry score. Pediatr Respirol Crit Care Med 2019;3:60-4

How to cite this URL:
Tansriratanawong S, Sritippayawan S, Veeravigrom M, Deerojanawong J. Usefulness of obstructive sleep apnea-18 as a predictor of moderate-to-severe obstructive sleep apnea in children who have normal/inconclusive McGill oximetry score. Pediatr Respirol Crit Care Med [serial online] 2019 [cited 2023 Jun 1];3:60-4. Available from: https://www.prccm.org/text.asp?2019/3/3/60/292385

Introduction

Overnight oximetry is a screening test for pediatric obstructive sleep apnea (OSA). However, those who demonstrate normal/inconclusive tests require polysomnography (PSG) for verifying the diagnosis.^[1] Since PSG has a long waiting list, an adjunct simple test for prioritizing these children to get the urgent PSG would be helpful.

OSA-18 is a simple quality of life (QoL) questionnaires developed by Franco et al. in 2000 and has been widely used in the pediatric OSA population.^{[2],[3],[4],[5],[6]} We, therefore, did the study to investigate the predictive value of Thai-Version OSA-18 in predicting moderate-to-severe OSA in children who had normal/inconclusive overnight oximetry.

Subjects and Methods

Study design

This was a cross-sectional study performed in the Department of Pediatrics in a University Hospital of Thailand. The study protocol was reviewed and approved by the institutional review board for human research study. Informed consent and assent (where applicable) were obtained from the participants and their legal guardians before enroll in the study.

Population

Children aged 3–15 years who had habitual snoring, adenotonsillar hypertrophy, and normal/inconclusive overnight oximetry, according to the McGill Oximetry Scoring System, were enrolled.^[7] The size of upper airway soft tissue was assessed by grading tonsillar size and X-ray of the lateral nasopharynx. All children had tonsillar size graded at least 3+ and adenoid hypertrophy demonstrated in the X-ray (adenoidal–nasopharyngeal ratio >0.6). Children whose caregivers did not understand the Thai language and those who were uncooperative with PSG or had the underlying conditions such as neuromuscular diseases, craniofacial anomalies, chronic lung diseases, asthma, and recent respiratory infection within 2 weeks before the study were excluded from the study.

Study protocol

All participants undertook attended overnight PSG to confirm the diagnosis of OSA and had Thai-Version OSA-18 QoL questionnaire completed by their caregivers on the following day after the PSG.

Polysomnography

The attended overnight PSG was performed at the Sleep Laboratory of the institute using the Sleep System Compumedics™ (Melbourne, Australia). The test was performed under the supervision of a well-trained sleep technician. The participants presented at the sleep laboratory at 8.30 P.M. and were discharged at 7.00 A.M. on the following day. All PSG used standard electroencephalographic monitoring, including frontal leads (F1, F2), central leads (C3, C4), occipital leads (O1, O2), and reference leads at the mastoids (M1, M2); electromyography; and electrooculography methodology. SpO₂ was measured with a finger probe, while airflow was measured by two methods, including nasal pressure transducer and oronasal thermocouple. The thoracic and abdominal respiratory movements were monitored by respiratory inductance plethysmography. The body position was measured by a position sensor attached to the anterior chest wall on the thoracic belt. Carbon dioxide was measured by end-tidal CO₂ monitoring or transcutaneous CO₂ monitoring. Sleep stages were scored in 30-s epochs, according to the American Academy of Sleep Medicine (AASM) Manual. Apnea was defined using oral–nasal thermocouple excursion, and hypopnea was defined using nasal pressure transducer excursion. Apnea, hypopnea, and respiratory effort-related arousals were scored using the standard criteria from the AASM updated manual (Versions 2.0, 2.1, 2.2, 2.3, and 2.4).^{[8],[9],[10],[11],[12]} OSA was diagnosed if the participants demonstrated the events of obstructive apnea–hypopnea ≥1/h of total sleep time (TST) (obstructive apnea/hypopnea index [OAHI] ≥1 per TST). The severity of OSA was graded as mild, moderate, and severe in accordance with the OAHI (mild OSA: OAHI 1–4/TST; moderate OSA: OAHI 5–10/TST; and severe OSA: OAHI >10/TST).^[13]

Quality of life assessment

Caregivers who regularly slept with the participants completed the QoL questionnaire on the following day after the PSG. The questionnaire used in this study was a Thai-Version OSA-18 developed and validated by Kuptanon et al.^[14] It was translated from the original English version of Franco's Pediatric OSA instrument (OSA-18) under the permission of the original authors.^[2] The questionnaire consisted of 18 items divided into five domains (sleep disturbance, physical symptoms, emotional symptoms, daytime functioning, and caregiver concerns). The 18 items were scored with a 7-point ordinal scale assessing the frequency of the specific symptoms. The scores on each of the 18 items were summed to produce a total score which ranged from 18 to 126. The higher score corresponded to the greater impact of OSA on QOL.

Sample size calculation

To investigate the best cutoff value of total OSA-18 score for predicting moderate-to-severe OSA, we used the following formula for calculating sample size:

Where P represented the estimated sensitivity of the test and Q was derived from 1 – P. The acceptable error (d) was set at 0.07, while α and β errors were set at 0.05 and 0.20, respectively. For the sensitivity of the test at 0.80, the calculated number of moderate-to-severe OSA children required for the study was 125. In accordance with the pilot survey, the proportion of moderate-to-severe OSA diagnosed by PSG among snoring children who had normal/inconclusive overnight oximetry in our institute was 56%. Therefore, the required number of enrolled participants was 224 cases.

Data acquisition and analysis

Collected data included demographic data, body weight, height, body mass index (BMI), total OSA-18 score, and OAHI. The participants were diagnosed with overweight and obese in accordance to the WHO criteria (https://www.who.int/growthref/who2007_bmi_for_age/en/). Mild and moderate-to-severe OSA were diagnosed basing upon the OAHI. Clinical data were compared between the two groups using the unpaired Student's t-test for continuous variables and the Chi-square or Fisher's exact test (where applicable) for categorical variables to identify the factors associated with moderate-to-severe OSA. Receiver operating characteristic (ROC) curve analysis was applied for identifying the best cutoff value of the total OSA-18 score for predicting moderate-to-severe OSA. Sensitivity, specificity, and positive and negative predictive values (PPV and NPV) of the best cutoff value were calculated. A two-tailed P < 0.05 was considered statistically significant. The analysis was performed using SPSS Version 16.0 (SPSS Inc., Chicago, IL, USA).

Results

Two hundred and eighteen children who had normal/inconclusive overnight oximetry were eligible and enrolled in the study. PSG revealed primary snoring, mild OSA, and moderate-to-severe OSA in 10 (5%), 76 (35%), and 132 cases (60%), respectively. Clinical data including demographic data and BMI as well as PSG findings and total OSA-18 score are shown in [Table 1]. Comparison between primary snoring/mild OSA and moderate-to-severe OSA groups found no difference in clinical data and mean total OSA-18 score between the two groups [Table 2]. However, subgroup analysis among children who never had medical treatment (such as montelukast and intranasal steroid) for their OSA (n = 55) found a higher total OSA-18 score in the moderate-to-severe compared to the primary snoring/mild OSA groups (80.5 ± 10.7 vs. 72.2 ± 14.4; P = 0.02) [Table 3]. The best cutoff value of the total OSA-18 score for predicting moderate-to-severe OSA in this subgroup analysis was 78 with the area under the curve of 0.70 (95% confidence interval [CI] 0.55–0.84; P = 0.01) [Figure 1]. The sensitivity, specificity, PPV, and NPV of this cutoff value were 61.5, 80, 72.7, and 69.7%, respectively. Children who had total OSA-18 score >78 had 2.1 times increased risk of moderate-to-severe OSA (95% CI 1.2–3.9; P = 0.02). There was a higher frequency of moderate-to-severe OSA among children who had total OSA-18 score >78 and overweight/obesity. However, this was not statistically significant [Table 3]. Combining total OSA-18 score >78 with overweight/obesity did not increase its predictivity for identifying moderate-to-severe OSA. The sensitivity, specificity, PPV, and NPV were 60%, 75%, 69.2%, and 66.7%, respectively, with the area under the curve of 0.77 (95% CI 0.60–0.94; P = 0.01) [Figure 2].

Table 1: Clinical data, polysomnography findings, and total obstructive sleep apnea-18 score of the study patients (n=218)

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Table 2: Comparison of clinical data and total obstructive sleep apnea-18 score between primary snoring/mild obstructive sleep apnea and moderate-to-severe obstructive sleep apnea groups

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Table 3: Comparison of clinical data and total obstructive sleep apnea-18 score between primary snoring/mild obstructive sleep apnea and moderate-to-severe obstructive sleep apnea groups (subgroup analysis among children who never had medical treatment for obstructive sleep apnea)

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Figure 1: The receiver operating characteristic curve of total obstructive sleep apnea-18 score >78 in medical treatment for obstructive sleep apnea.

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Figure 2: The receiver operating characteristic curve of total obstructive sleep apnea-18 score >78 in predicting moderate-to-severe obstructive sleep apnea in snoring children who were overweight/obese and never had medical treatment for obstructive sleep apnea.

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Discussion

In this study, we found that almost all of the children who had normal/inconclusive overnight oximetry had OSA demonstrated by PSG. Moreover, 60% of the cases had the moderate-to-severe disease. The high false-negative predictive value of the test is a known major limitation of overnight oximetry as a screening test for pediatric OSA. In the context where PSG is not widely available and costly, overnight oximetry still serves as the first test for screening OSA in children. However, the majority of the cases show normal or inconclusive results, which eventually require PSG to verify the diagnosis. A high proportion of moderate-to-severe OSA in children who had normal/inconclusive overnight oximetry in this study suggested that a measure to prioritize these children for the urgent diagnostic PSG would be helpful.

There have been many simple tests developed for substituting overnight PSG in pediatric OSA. OSA-18 is a simple questionnaire for QoL assessment and has been widely studied in snoring children. However, the relationship between total OSA-18 score and OSA severity was various among the studies.^{[14],[15],[16],[17],[18],[19],[20],[21]} The discrepancies of the results could be due to the different diagnostic criteria for OSA, versions of PSG scoring system, and patient characteristics such as ethnicity, socioeconomic background, and current therapeutic interventions that could affect the QoL assessment. In this study, we evaluated the relationship between total OSA-18 score and OSA severity in habitually snoring children focusing on those who had adenotonsillar hypertrophy and normal/inconclusive overnight oximetry. We applied AASM updated manual 2012 for sleep staging and event scorings which is more sensitive in identifying obstructive hypopnea events when compared to the previous studies.^{[8],[9],[10],[11],[12]}

In this study, we found no relationship between total OSA-18 score and OSA severity among the overall study population. However, subgroup analysis focusing on children who never had medical treatment (montelukast or intranasal steroid) for their OSA showed a positive relationship between total OSA-18 score and OSA severity. This implied that therapeutic intervention might have some impacts on this relationship. It has been reported that both medical and surgical interventions improved PSG findings and QoL in children who had OSA secondary to adenotonsillar hypertrophy.^{[22],[23],[24],[25],[26],[27]} However, the improvement of QoL might not be parallel with the improvement of PSG findings after therapeutic interventions. Kang et al. studied QoL and AHI before and after adenotonsillectomy in pediatric OSA and found total OSA-18 score was markedly improved in 93% of the cases while 45% still had residual OSA documented by PSG.^[26] The authors addressed the possibility of “placebo effect” of the surgery for the discrepancy between QoL and AHI improvement after the treatment. In addition, they found a positive correlation between AHI and total OSA-18 score in the patients only before but not after the surgery.^[26] Currently, there has been no study investigated whether medical treatment could have the same effect on the inconsistency between subjective and objective improvements in pediatric OSA. However, in this study, a relationship between total OSA-18 score and OAHI was found only among children who never had medical treatment for their OSA. These findings implied that therapeutic interventions, either medical or surgical treatment, could have an impact on the relationship between total OSA-18 score and OSA severity assessed by PSG. It could be possible that the various relationships between OSA-18 score and OSA severity reported in the previous studies were affected by the various therapeutic interventions in the study population.

In this study, the ROC curve analysis showed that total OSA-18 score >78 was the best cutoff value for predicting moderate-to-severe OSA (with the area under the curve of 0.70) in children who had normal/inconclusive overnight oximetry and never had medical treatment for their OSA. However, the sensitivity, specificity, PPV, and NPV of this cutoff value were not good. Further study in a larger population would provide us a precise validity of OSA-18 in predicting OSA severity in this population.

It has been known that obesity is another risk factor of OSA. In this study, moderate-to-severe OSA seemed to be more prevalent among children who had total OSA-18 score >78 and overweight/obesity [Table 3]. However, the predictivity of this combination for identifying moderate-to-severe OSA was not good either. Further study to identify other helpful add-on parameters such as Mallampati score, nasal turbinate assessment which represents the size of upper airway soft tissue, would be helpful to identify the best diagnostic tool for prioritizing children who need urgent diagnostic PSG.

Conclusions

We found an association between high total OSA-18 score and the occurrence of moderate-to-severe OSA in snoring children who had normal/inconclusive overnight oximetry, especially among those who never had medical treatment for their OSA. However, the best cutoff value of total OSA-18 score and other potential add-on parameters to increase its validity for prioritizing these children to get the urgent diagnostic PSG are still needed to be investigated.

Financial support and sponsorship

This study was financially supported by Ratchadapiseksompotch Research Fund, Faculty of Medicine, Chulalongkorn University (Grant No. RA58/013).

Conflicts of interest

There are no conflicts of interest.

References

1.	Marcus CL, Brooks LJ, Draper KA, Gozal D, Halbower AC, Jones J, et al. Diagnosis and management of childhood obstructive sleep apnea syndrome. Pediatrics 2012;130:576-84.
2.	Franco RA Jr., Rosenfeld RM, Rao M. First place-resident clinical science award 1999. Quality of life for children with obstructive sleep apnea. Otolaryngol Head Neck Surg 2000;123:9-16.
3.	Fischer Y, Rettinger G, Dorn M. Long term change in quality of life after adenotonsillectomy for pediatric obstructive sleep disorders. Laryngorhinootologie 2006;85:809-18.
4.	Friedman M, Samuelson CG, Hamilton C, Maley A, Taylor D, Kelley K, et al. Modified adenotonsillectomy to improve cure rates for pediatric obstructive sleep apnea: A randomized controlled trial. Otolaryngol Head Neck Surg 2012;147:132-8.
5.	Tripuraneni M, Paruthi S, Armbrecht ES, Mitchell RB. Obstructive sleep apnea in children. Laryngoscope 2013;123:1289-93.
6.	Ericsson E, Lundeborg I, Hultcrantz E. Child behavior and quality of life before and after tonsillotomy versus tonsillectomy. Int J Pediatr Otorhinolaryngol 2009;73:1254-62.
7.	Nixon GM, Kermack AS, Davis GM, Manoukian JJ, Brown KA, Brouillette RT. Planning adenotonsillectomy in children with obstructive sleep apnea: The role of overnight oximetry. Pediatrics 2004;113:e19-25.
8.	Berry RB, Brooks R, Gamaldo CE, Harding SM, Marcus CL, Vaughn V. The AASM manual for the scoring of sleep and associated events: Rules, terminology and technical specifications, version 2.0. Illinois, Darien: American Academy of Sleep Medicine; 2012.
9.	Berry RB, Brooks R, Gamaldo CE, Harding SM, Lloyd RM, Marcus CL, et al. The AASM manual for the scoring of sleep and associated events: Rules, terminology and technical specifications, version 2.1. Illinois, Darien: American Academy of Sleep Medicine; 2014.
10.	Berry RB, Brooks R, Gamaldo CE, Harding SM, Lloyd RM, Marcus CL, et al. The AASM manual for the scoring of sleep and associated events: Rules, terminology and technical specifications, version 2.2. Illinois, Darien: American Academy of Sleep Medicine; 2015.
11.	Berry RB, Brooks R, Gamaldo CE, Harding SM, Lloyd RM, Marcus CL, et al. The AASM manual for the scoring of sleep and associated events: Rules, terminology and technical specifications, version 2.3. Illinois, Darien: American Academy of Sleep Medicine; 2016.
12.	Berry RB, Brooks R, Gamaldo CE, Harding SM, Lloyd RM, Quan SF, et al. The AASM manual for the scoring of sleep and associated events: Rules, terminology and technical specifications, version 2.4. Illinois, Darien: American Academy of Sleep Medicine; 2017.
13.	Katz ES, Marcus CL. Diagnosis of obstructive sleep apnea. In: Sheldon SH, Ferber R, Kryger MH, Gozal D, editors. Principles and Practice of Pediatric Sleep Medicine. Philadelphia: Elsevier; 2014. p. 221-30.
14.	Kuptanon T, Chukumnerd J, Leejakpai A, Preutthipan A. Reliability and validity of Thai version quality of life questionnaire (OSA-18) for pediatric obstructive sleep apnea. J Med Assoc Thai 2015;98:464-71.
15.	Borgström A, Nerfeldt P, Friberg D. Questionnaire OSA-18 has poor validity compared to polysomnography in pediatric obstructive sleep apnea. Int J Pediatr Otorhinolaryngol 2013;77:1864-8.
16.	Hasukic B. OSA-18 survey in evaluation of sleep-disordered breathing in children with adenotonsillar hypertrophy. Med Arch 2013;67:111-4.
17.	Constantin E, Tewfik TL, Brouillette RT. Can the OSA-18 quality-of-life questionnaire detect obstructive sleep apnea in children? Pediatrics 2010;125:e162-8.
18.	Ishman SL, Yang CJ, Cohen AP, Benke JR, Meinzen-Derr JK, Anderson RM, et al. Is the OSA-18 predictive of obstructive sleep apnea: Comparison to polysomnography. Laryngoscope 2015;125:1491-5.
19.	Kang KT, Weng WC, Yeh TH, Lee PL, Hsu WC. Validation of the Chinese version OSA-18 quality of life questionnaire in Taiwanese children with obstructive sleep apnea. J Formos Med Assoc 2014;113:454-62.
20.	Mousailidis GK, Lachanas VA, Skoulakis CE, Sakellariou A, Exarchos ST, Kaditis AG, et al. Cross-cultural adaptation and validation of the Greek OSA-18 questionnaire in children undergoing polysomnography. Int J Pediatr Otorhinolaryngol 2014;78:2097-102.
21.	Walter LM, Biggs SN, Cikor N, Rowe K, Davey MJ, Horne RS, et al. The efficacy of the OSA-18 as a waiting list triage tool for OSA in children. Sleep Breath 2016;20:837-44.
22.	Gudnadottir G, Ellegård E, Hellgren J. Intranasal budesonide and quality of life in pediatric sleep-disordered breathing: A randomized controlled trial. Otolaryngol Head Neck Surg 2018;158:752-9.
23.	Kheirandish-Gozal L, Bandla HP, Gozal D. Montelukast for children with obstructive sleep apnea: Results of a double-blind, randomized, placebo-controlled trial. Ann Am Thorac Soc 2016;13:1736-41.
24.	Goldbart AD, Greenberg-Dotan S, Tal A. Montelukast for children with obstructive sleep apnea: A double-blind, placebo-controlled study. Pediatrics 2012;130:e575-80.
25.	Todd CA, Bareiss AK, McCoul ED, Rodriguez KH. Adenotonsillectomy for obstructive sleep apnea and quality of life: Systematic review and meta-analysis. Otolaryngol Head Neck Surg 2017;157:767-73.
26.	Kang KT, Weng WC, Lee CH, Lee PL, Hsu WC. Discrepancy between objective and subjective outcomes after adenotonsillectomy in children with obstructive sleep apnea syndrome. Otolaryngol Head Neck Surg 2014;151:150-8.
27.	Bhattacharjee R, Kheirandish-Gozal L, Spruyt K, Mitchell RB, Promchiarak J, Simakajornboon N, et al. Adenotonsillectomy outcomes in treatment of obstructive sleep apnea in children: A multicenter retrospective study. Am J Respir Crit Care Med 2010;182:676-83.