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Volume 14 No. 08
Earn CME
Accepted Papers





Scientific Investigations

Predictors of Obtaining Polysomnography Among Otolaryngologists Prior to Adenotonsillectomy for Childhood Sleep-Disordered Breathing

Derek J. Lam, MD, MPH1; Steven A. Shea, PhD2,3; Edward M. Weaver, MD, MPH4; Ron B. Mitchell, MD5
1Oregon Health and Science University, Portland, Oregon; 2Oregon Health and Science University, Portland Oregon; 3Oregon Institute of Occupational Health Sciences, Portland Oregon; 4University of Washington, Seattle, Washington; 5Children's Medical Center Dallas and UT Southwestern, Dallas Texas

ABSTRACT

Study Objectives:

(1) To assess the predictors for obtaining polysomnography (PSG) in children undergoing adenotonsillectomy (AT) for sleep-disordered breathing, and (2) to estimate the adherence to the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) guideline recommendations for pre-AT PSG.

Methods:

This was a retrospective cohort study of children who were seen in the Pediatric Otolaryngology Clinic and underwent AT for sleep-disordered breathing over a 13-month period at a single tertiary care children's hospital. Patients with and without pre-AT PSG were compared using bivariate and logistic regression analysis to identify predictors for PSG. Electronic medical records were reviewed for demographic variables, medical comorbidities, and PSG data. Adherence to AAO-HNS guideline recommendations was estimated by calculating the proportion of patients who had a PSG among those who met the recommended criteria for pre-AT PSG.

Results:

Mean age was 6.6 ± 3.6 years with 53% male. A total of 65 of 324 children (20%) underwent PSG prior to AT. The only factor significantly associated with pre-AT PSG was age 1 to 3 years (odds ratio 4.5, 95% confidence interval [2.2, 9.0], P < .001). Among patients who met AAO-HNS criteria for pre-AT PSG, 28 of 128 (20%) underwent PSG compared to 35 of 186 (19%) who did not meet criteria (odds ratio 1.0, 95% confidence interval [0.6, 1.9], P = .87).

Conclusions:

Among children who underwent AT, the only significant predictor of obtaining pre-AT PSG was age 1 to 3 years. The rate of adherence to the AAO-HNS guideline recommendations was low (20%), which represents an educational opportunity.

Citation:

Lam DJ, Shea SA, Weaver EM, Mitchell RB. Predictors of obtaining polysomnography among otolaryngologists prior to adenotonsillectomy for childhood sleep-disordered breathing. J Clin Sleep Med. 2018;14(8):1361–1367.


BRIEF SUMMARY

Current Knowledge/Study Rationale: Evidence examining indications among pediatric otolaryngologists for obtaining polysomnography prior to adenotonsillectomy is limited, primarily relying on provider surveys that are subject to recall and confirmation bias. This study was undertaken to objectively examine potential predictors of polysomnography among adenotonsillectomy patients, and to assess adherence to the 2011 American Academy of Otolaryngology-Head and Neck Surgery polysomnography guideline.

Study Impact: In this single-institution study, age 1 to 3 years was the only significant predictor of polysomnography with a low overall rate of obtaining polysomnography testing among pediatric adenotonsillectomy patients. This study may help to highlight awareness of published polysomnography guidelines and promote discussion regarding the benefits versus practicality of greater adherence to these guidelines.

INTRODUCTION

Pediatric sleep-disordered breathing (SDB) comprises a spectrum of sleep disorders that ranges between snoring and obstructive sleep apnea (OSA). SDB has become the most common indication for tonsillectomy with or without adenoidectomy (adenotonsillectomy or AT).1 There is general consensus that polysomnography (PSG) is the gold standard for the diagnosis and quantification of pediatric OSA and for distinguishing it from snoring.2 However, in most patients who undergo AT for treatment of SDB the diagnosis is made based on a history and clinical examination alone.3,4 Also, several studies have suggested that snoring may have associated neurocognitive sequelae similar to mild OSA, so distinguishing the severity of SDB may not be clinically important or affect the sequelae of the untreated sleep disorder.57 Nevertheless, several national organizations have published guidelines for the diagnosis of OSA that recommend obtaining PSG prior to AT.810 The American Academy of Pediatrics (AAP) and American Academy of Sleep Medicine (AASM) both recommend PSG to confirm a diagnosis of OSA for any child being considered for AT. In contrast, the 2011 American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) guidelines recommend PSG in children who are considered high risk for perioperative morbidity (eg, patients with obesity, neuromuscular disorders, Down syndrome, sickle cell anemia, craniofacial anomalies, neuromuscular disorders, mucopolysaccharidoses) or where there is uncertainty about the diagnosis because of an unclear history (eg, because of disagreement between caregivers about symptom severity) or discordance between symptoms and physical examination findings (ie, patients with small tonsils). Despite these guideline recommendations, for most patients, the decision to undergo AT is made based on the recommendations of the otolaryngologist without PSG.4 In those who do undergo PSG, the indications for this testing are variable and inconsistent and the rate of adherence to guideline recommendations is unknown.3,4 The aims of this study were: (1) to assess the predictors for obtaining pre-AT PSG among patients referred for AT at a single academic institution, and (2) to estimate the rate of adherence to the 2011 AAO-HNS guideline recommendations for pre-AT PSG.

METHODS

Study Design and Population

This was a retrospective case series of children who underwent AT between September 1, 2011 and September 30, 2012 at the tertiary care Doernbecher Children's Hospital at Oregon Health and Science University. Inclusion criteria were: (1) patients who underwent AT during the study period, identified by screening a billing database for tonsillectomy with or without adenoidectomy CPT codes (42820, 42821, 42825, 42826); (2) primary indications for surgery included SDB or OSA; (3) age 1 to 18 years at the time of AT; (4) surgery was performed by one of three pediatric otolaryngologists during the study period. Exclusion criteria were: (1) patients referred from a sleep medicine clinic with prior PSG, (2) presence of a previous tracheostomy; (3) other known airway disorders (eg, laryngomalacia, subglottic or tracheal stenosis, tracheobronchomalacia); or (4) concurrent major airway procedures that might potentially affect the decision to obtain PSG such as expansion pharyngoplasty or injection laryngoplasty. The electronic medical record (Epic Systems, Verona, Wisconsin, United States) was reviewed for demographics, comorbidities, PSG data, and surgical reports. The study was approved by the Oregon Health and Science University Institutional Review Board and exempted from consent because of the retrospective nature of the study.

Potential Predictors

Predictors of interest included demographic variables (age, sex, insurance type) and medical comorbidities (obesity, neuromuscular disorder, craniofacial anomaly, Down syndrome, other syndrome, prematurity, developmental delay, asthma, chronic lung disease, congenital heart disease). These were extracted from problem lists and past medical history. Symptom history and tonsil size were extracted from otolaryngology clinic notes.

Age was dichotomized as 1 to 3 years or older than 3 years, insurance type was dichotomized as Medicaid or other, and all comorbidities were dichotomized as present or absent. Obesity was defined as a body mass index greater than the 95th percentile for age and sex according to the population growth charts published by the Centers for Disease Control and Prevention.11 SDB was diagnosed when a child did not undergo PSG but had a history of snoring for at least 3 months and physical examination of adenotonsillar hypertrophy. OSA was defined in children with PSG and an obstructive apnea-hypopnea index (oAHI) ≥ 2 events/h.9 Patients with oAHI < 2 events/h were considered to not have OSA. OSA severity was categorized based on oAHI (2.0–4.9, 5.0–9.9, ≥ 10.0 events/h corresponding to mild, moderate, and severe OSA respectively).

Analysis

Categorical data are presented as counts with percentages. Continuous data are presented as mean with standard deviation (SD). To test for significant differences between patients with and without pre-AT PSG, bivariate analyses were performed using Student t tests for continuous variables or chi-square tests for dichotomous or categorical variables. To test for significant associations between these predictors and having had a PSG, univariate logistic regressions were performed and predictors with associations approaching statistical significance (P < .2) were then included in a multivariable logistic regression model to determine the independent association of these predictors with PSG. A value of P < .2 threshold in univariate analysis was used for subsequent inclusion in multivariable regression models in order to be inclusive of potential predictors that might achieve statistical significance (P < .05) when adjusting for other covariates in a multivariable model.

To assess adherence to the AAO-HNS guidelines for pre-AT PSG, we calculated the proportion with pre-AT PSG among patients who would meet the recommended criteria for pre-AT PSG (obesity, Down syndrome, craniofacial anomalies, neuro-muscular disorders, sickle cell disease, mucopolysaccharidosis, or grade 0 or 1 tonsils discordant with SDB symptoms). This portion of the analysis was restricted to patients age 2 to 18 years, the intended age range for which these guidelines were developed. All analyses were performed using Stata 12.1 (College Station, Texas, United States).

RESULTS

Of 457 children who underwent AT during the study period, 324 children met inclusion and exclusion criteria. The mean age was 6.6 years with a slight male predominance and 58% had Medicaid insurance (Table 1). The most common comorbidities were obesity (33%), developmental delay or autism (13%), and dysphagia (11%). A total of 65 of 324 (20%) underwent PSG prior to AT. Among those with PSG, 18% had an oAHI < 2 (but underwent AT), whereas the remainder had a fairly even spectrum of OSA severity (Table 1).

Characteristics in patients with and without preoperative PSG.

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Table 1

Characteristics in patients with and without preoperative PSG.

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Children who underwent pre-AT PSG were more likely to be 1 to 3 years of age, have craniofacial anomalies, Down syndrome, syndromic diagnosis (other than trisomy 21), prematurity, developmental delay, congenital heart disease, or other airway anomalies (all P < .05, Table 1). Patients without trisomy 21 had the highest rate of PSG testing (47%), followed by patients with Down syndrome (46%), age 1 to 3 years (43%), craniofacial anomalies (41%), neurological conditions (31%), and obesity (20%) (Table 1).

In multivariable regression analysis, the only significant independent predictor of pre-AT PSG was age 1 to 3 years (odds ratio [OR] 4.5, 95% confidence interval [CI] [2.2, 9.0], P < .001). All other covariates included in the model (ie, Medicaid insurance, tonsil size, obesity, neuromuscular conditions, craniofacial anomalies, Down syndrome, absence of trisomy 21 syndrome, asthma, congenital heart disease, and developmental delay/autism) did not have significant associations in the adjusted model (Figure 1). Among children age 1 to 3 years, 22 of 50 (44%) underwent PSG compared to 44 of 275 (16%) in children age 3 years and older. In comparing these two age groups, there was a significantly greater proportion of boys in the younger age group compared to the older age group (66% versus 51%, P = .03), but no significant differences in the rate of comorbidities.

Predictors of obtaining pre-AT PSG.

AT = adenotonsillectomy, PSG = polysomnography.

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Figure 1

Predictors of obtaining pre-AT PSG.

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A total of 128 of 314 (41%) met the AAO-HNS guideline criteria for pre-AT PSG (10 patients were excluded from this analysis because they were younger than 2 years of age). Among patients who met criteria, 25 of 128 (20%) underwent pre-AT PSG compared to 35 of 186 (19%) among those who did not meet one of the AAO-HNS criteria (OR 1.0, 95% CI [0.6, 1.9], P = .87). Within the subgroup of patients who met AAO-HNS criteria for PSG (n = 128), Down syndrome was the only comorbidity that was significantly associated with PSG (Table 2). For other comorbidities in this subgroup, there was a similar distribution among those who did and did not obtain PSG. When we examined the subgroup of patients who did not meet one of the AAO-HNS criteria for PSG (n = 186), compared to patients who did not undergo PSG, those who still underwent PSG were younger and more likely to have a history of prematurity (Table 3). There also appeared to be a greater proportion of boys who underwent PSG in this subgroup, though this difference did not achieve statistical significance.

Characteristics among patients meeting one or more AAO-HNS criteria for pre-AT PSG.

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Table 2

Characteristics among patients meeting one or more AAO-HNS criteria for pre-AT PSG.

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Characteristics of patients who did not meet AAO-HNS criteria for pre-AT PSG.

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Table 3

Characteristics of patients who did not meet AAO-HNS criteria for pre-AT PSG.

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DISCUSSION

The current study demonstrates a 20% rate of PSG testing among patients who underwent AT for SDB at our institution. There was no significant difference in the rate of testing among children who met one or more of the AAO-HNS criteria for pre-AT PSG (obesity, Down syndrome, craniofacial anomalies, neuromuscular disorders, sickle cell disease, mucopolysaccharidosis, small tonsils) and those who did not. In adjusted analysis, none of the aforementioned criteria were independently associated with pre-AT PSG; the only significant predictor was age 1 to 3 years.

The guidelines published by the AAO-HNS recommend indications for pre-AT PSG based on the risk of perioperative morbidity or clinical uncertainty regarding the need for surgery.10 However, given the discrepancy among guidelines from the AAP, the AASM and AAO-HNS, the indications for obtaining a pre-AT PSG remain controversial and the subject of continued discussion.1214 Two recent surveys of practice patterns among pediatric otolaryngologists suggest that most patients undergoing AT do not undergo preoperative PSG.3,4 In these studies, the primary reasons for ordering a preoperative PSG were inconsistent history and physical examination, uncertainty about the need for surgery, age younger than 3 years, or presence of comorbidities such as Down syndrome or obesity.4,15 Although most otolaryngologists are aware of the AAO-HNS practice guidelines,15 it remains unclear to what extent providers are adhering to these recommendations.

In multiple studies, age younger than 3 years has been shown to be a consistent predictor of perioperative respiratory morbidity,1621 so it is not surprising that this was significantly associated with obtaining pre-AT PSG. Because of their smaller airway caliber and relative macroglossia, younger children are more significantly affected by postoperative edema with greater risk of acute airway obstruction. It has also been proposed that younger children may have immature responses to disturbances in ventilation, especially in a setting of OSA where chronic hypercapnia may blunt respiratory drive and arousal responses. Particularly in this younger age group, PSG testing can help to guide perioperative management by identifying children with severe OSA and prompting an increased level of postoperative care. Because of the increased perioperative risk in this age group, the motivation to obtain PSG testing likely also includes the desire to confirm the OSA diagnosis and possibly avoid the risk of perioperative complications with a negative study. It is worth noting that age younger than 3 years is not one of the indications for PSG recommended in the AAO-HNS guidelines, although it is mentioned in the 2012 AAP guideline on the diagnosis and management of childhood OSA as a risk factor for perioperative morbidity.2 This would seem to suggest greater adherence to the AAP guideline than the AAO-HNS guideline even among otolaryngologists. However, the fact that a portion of the study review period predates the latest AAP guideline and the lack of association with other risk factors also mentioned in the AAP guideline may indicate a greater reliance on clinical experience and the preponderance of evidence, indicating young age as a risk factor for perioperative morbidity more than either published guideline.

It is interesting that when adjusting for all the included covariates, other comorbidities including obesity, neuromuscular conditions, craniofacial anomalies, and Down syndrome were not associated with obtaining a preoperative PSG. There are several potential explanations for the lack of association with these comorbidities. First, patients with these comorbidities may still be referred for PSG at a greater rate than other patients but when adjusting for all other covariates in the model, these risk factors were less strongly associated with pre-AT PSG than young age. Second, this may reflect the variation in severity of these comorbidities in the overall cohort, such that those with milder forms may not generate sufficient concern regarding perioperative morbidity to prompt a PSG. Third, it may be that some patients with these comorbidities were so symptomatic that the decision was made to forego a PSG and expedite treatment with AT based on history and physical examination alone.

At Oregon Health and Science University, PSG is ordered by providers in sleep medicine or pediatric otolaryngology, and not by primary care providers. Thus, patients with suspected OSA are referred by their primary care providers to either a sleep medicine physician or pediatric otolaryngologist who determines the need for PSG at his or her discretion without specific consensus protocols for testing. We believe this provider discretion in ordering PSG is similar to most tertiary care hospitals in the United States. We did find a relatively high rate of pre-AT PSG testing (20%) compared to other centers where rates of PSG testing have been estimated to occur in only 10% of patients.3 When we examined the rate of adherence to the 2011 AAO-HNS guidelines for obtaining pre-AT PSG, we found that only 20% of the patients who met the recommended criteria for testing underwent PSG, irrespective of age or underlying comorbidity. These findings are consistent with a recent survey report by Friedman et al. where otolaryngologists reported ordering a pre-AT PSG 22% of the time in children younger than 3 years, 38% in obese children, and 56% in children with Down syndrome.4 The low rate of obtaining PSG may be because of long wait times that, at our institution, ranged from 1 to 3 months depending on the time of year. Friedman et al. noted that although 86% of respondents were able to refer to a pediatric sleep center, the average wait time was 5.7 weeks, which represented a long delay for parents or providers with a symptomatic child.

Costs and benefits of full adherence to the AAO-HNS guideline are unclear. Full adherence would represent a substantial increase over the current volume of PSG testing at our institution with the associated increased costs (estimated at nearly $200,000 more per year based on current charges for PSG) and increased delays in treatment because of limited sleep laboratory capacity. The potential to avoid surgery among those patients with negative testing is a possible benefit, though given the high prevalence of OSA among children who meet one or more of the AAO-HNS criteria for pre-AT PSG (with the exception of small tonsils), it is unclear whether this represents a reasonable use of resources in a clearly symptomatic patient. Although there are a few studies demonstrating the benefit of PSG in the management of perioperative morbidity in high-risk children,16,22,23 this study was not designed or intended to address the effect of PSG on perioperative outcomes.

This study has several limitations. First, the data were collected retrospectively with potential omissions or inaccuracies in documentation. A related limitation is the selection bias of excluding patients who underwent PSG prior to referral to pediatric otolaryngology and patients whose PSG was ultimately negative and therefore did not undergo AT. A query of our sleep laboratory database revealed that approximately 30% of the studies done during the study period were negative for OSA, suggesting the proportion of patients who underwent PSG but were not included in our analysis is significant. It is noteworthy that 12 patients (19% of those who underwent PSG) had an AT despite a negative study, indicating that a negative study did not always preclude surgery. This was presumably because of significant symptoms of SDB and concern that the negative PSG may not have accurately reflected typical sleep at home. Nevertheless, if there was a substantial difference in the comorbidities of patients who had previous PSG or did not have an AT because of a negative PSG compared to those who underwent AT, then this could have the potential to affect both the analysis of predictors of PSG and the rate of adherence to published guidelines. With respect to guideline adherence, this could have resulted in lower observed referral rates for PSG and therefore a lower adherence rate. However, given that most of the comorbidities comprising the criteria for pre-AT PSG in the AAO-HNS guideline have relatively high prevalence of OSA (Down syndrome, obesity, neuromuscular disorders, craniofacial anomalies), for any of these patients who underwent PSG there would be a low likelihood of a negative study. Future studies should address this limitation by including all patients being evaluated for OSA and possible AT. Finally, this study represents the experience at a single institution with a limited sample size over a relatively short timeframe not long after publication of the AAO-HNS guidelines. It is possible that the providers ordering PSG were not immediately aware of the guideline recommendations, which could potentially account for the low rate of PSG testing even among patients who meet one or more criteria for testing in the AAO-HNS guideline. Thus, our findings may not reflect practice patterns at other institutions or changes over a longer time period. Future studies should ideally include multi-institutional data collection over a broader range of years to determine whether these patterns of obtaining PSG changed in the subsequent years to better reflect the AAO-HNS guideline recommendations. Despite these limitations, our findings are consistent with two previously published survey studies.3,4 suggesting that our experience may be similar to that at other institutions. Rather than relying on subjective recall of general practice patterns, this study provides the first objective data on the use of pre-AT PSG among pediatric otolaryngologists.

CONCLUSIONS

This study demonstrates that in a population of children undergoing AT for OSA, age 1 to 3 years was the only independent predictor of obtaining pre-AT PSG. Consistent with previous survey studies, the overall rate of adherence to the AAO-HNS published guidelines for pre-AT PSG was low, although this may be due in part to the study review period occurring shortly after guideline publication. Further study is needed to examine the changing patterns of obtaining PSG before AT and the potential benefits of pre-AT PSG, which must be balanced against the cost and burden of trying to meet the standard of published guidelines.

DISCLOSURE STATEMENT

Data from this study were presented at the annual meeting of the Associated Professional Sleep Societies in Seattle, WA June 6-10, 2015. Work for this study was performed at Oregon Health and Science University in Portland, OR. All authors have seen and approved this manuscript. Financial support: Lam: NIH/NHLBI K23 HL127132 (PI); Shea: NIH/NHLBI R01 HL125893 (PI); Mitchell NIH/NHLBI U01 HL125295 (Site PI). The authors report no conflicts of interest.

ABBREVIATIONS

AAO-HNS

American Academy of Otolaryngology-Head and Neck Surgery

AHI

apnea-hypopnea index

AT

adenotonsillectomy

OSA

obstructive sleep apnea

PSG

polysomnography

SD

standard deviation

SDB

sleep-disordered breathing

ACKNOWLEDGMENTS

The authors thank Eleni O'Neill, MPH for her assistance with data extraction, cleaning, and coding.

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