September 2019 HSC Section 1 Congenital and Pediatric Problems

Original Investigation Research

Predictors of Obstructive Sleep Apnea Severity in Adolescents

Table 2. Polysomnographic Data for Normal-Weight, Overweight, and Obese Adolescents a

Mean (SD)

Abbreviations: AHI, apnea hypopnea index; CAI, central apnea index; CO 2 , carbon dioxide; REM, rapid eye movement; Sa O 2, oxygen saturation; Sa O 2 nadir, lowest pulse oximeter measured hemoglobin saturation; TST>50 CO 2 , total sleep time at greater than 50 mm Hg blood CO 2 saturation. a Normal weight, BMI, 5% to 85%; obese, BMI 95%; overweight, BMI 85%-95%. b Based on ANOVA.

Normal Weight

Absolute Difference in Mean (95% CI) b

Variable

Total

Overweight 9.2 (23.7)

Obese

AHI CAI

14.9 (28.7) 0.51 (1.6)

7.2 (21.6) 0.15 (0.32)

18.3 (30.9) 0.61 (1.9) 14.5 (7.1) 75.9 (16.7) 11.4 (11.2) 87.5 (7.7) 47.5 (5.7) 7.3 (19.5)

11 (0.02 to 22)

0.44 (0.92)

0.46 (−0.16 to 1.01) 1.5 (−0.83 to 3.8) 6.0 (0.65 to 11.4) 5.8 (−1.9 to 13.4) 3.8 (0.98 to 6.6) 2.5 (−0.3 to 5.3) 5.7 (−0.78 to 9.6)

REM

15 (7.0)

15.8 (7.1) 79.2 (17.4) 12.9 (13.6) 91.3 (5.2) 47.5 (5.7)

16 (6.7) 82.0 (12)

Sleep efficiency Arousal index

77.6 (16.1) 17.2 (19.7) 88.2 (7.3) 47.4 (6.0) 5.5 (16.7)

15.0 (17.0) 88.6 (6.6) 48.2 (7.6)

Sa O 2

nadir

Peak CO 2

TST>50 CO 2

1.6 (6.6)

2.7 (8.5)

Table 3. ANOVA Analysis of Demographic and Clinical Parameters and the Apnea Hypopnea Index Source of Variation Partial SS df MS F P Value Model 24 721 6 4120 5.6 <.001 Age 543 1 543 0.74 .39 Male 2082 1 2082 2.8 .09 Weight status 4743 2 2371 3.2 .04 Tonsil hypertrophy 18 004 1 18 004 24 <.001 African American 1257 1 1257 1.7 .19 Error 159 758 217 736

Abbreviations: df, degrees of freedom; F, test statistic for F distribution; MS, mean square; partial SS, sum of squares.

cents. These included in obese adolescents: a higher AHI of 11 (95% CI, 0.02-22.0); the sleep efficiency was 6.0 lower (95% CI, 0.65-11.4); and the oxygen saturation nadir was 3.8% (95% CI, 0.98-6.6) lower. There were no significant differences in the time spent in central apnea index, REM sleep, arousal in- dex, the peak carbon dioxide, and time spent in sleep with carbon dioxide greater than 50% between normal weight, overweight, and obese adolescents. Table 3 is a summary of the ANOVA analysis of demo- graphic and clinical parameters and the AHI. Therewas a posi- tive correlation between theweight classification and the AHI. The AHI was also positively correlated with tonsillar hyper- trophy. The positive correlation between the weight classifi- cation and tonsillar hypertrophy and the AHI remained after controlling for the effects of each other with multivariable analysis. This correlation also remained significant after con- trolling for age, sex, African American ethnicity, allergic rhi- nitis, asthma, and GERD. Table 4 is a summary of univariate logistic regression of demographic and clinical parameters for severeOSA (AHI ≥10). Male sex nearly doubled the odds ratio for severeOSA (OR, 1.8; 95%CI, 1.0-3.2). Similarly, increasingweight classification in- creased the odds ratio for severe OSA (OR, 2.0; 95% CI, 1.3- 3.2). Adolescents with tonsillar hypertrophy were more than 3 times as likely to have severe OSA (AHI ≥10) compared with thosewithout tonsillar hypertrophy (OR, 3.2; 95%CI, −8 to 5.8) ( Table 5 ). After controlling for the effects of the other vari- ables (weight classification and tonsillar hypertrophywhen as- sessing male sex), sex, BMI z score, and tonsillar hypertrophy continued to predict severe OSA with odds ratios of 2.1, 2.2, and 4.0 respectively. Age and African American ethnicity were not significant predictors of severe OSA, nor were the presence of asthma, allergic rhinitis, or GERD.

Discussion In this study of 224 adolescents between the ages of 12 and 17 years who underwent PSG, obesity and tonsillar hypertrophy were associated with increasing severity of OSA as measured by AHI. Severe OSA (AHI >10) was predicted by obesity, male sex, and tonsillar hypertrophy. Adolescents with higher obe- sity also had a lower blood oxygen nadir and sleep efficiency. African American ethnicity and age were not correlated with OSA severity. There are few prior studies that reported on the associa- tion between weight classification and OSA in adolescents, 15 andmost published studies have focused on children younger than 12 years. 2,8,15-21 In addition, direct comparison of study results is difficult becausemeasures of OSA severity and defi- nitions of overweight and obesity vary between studies. How- ever, our finding of a positive correlation between increasing obesity andOSA severity in adolescents is consistentwithprior reported studies. Redline et al 15 studied 270 children aged 13 to 16 years and found that obesity (BMI >95th percentile) was strongly correlated with OSA as defined by an AHI greater or equal to 5 ( P < .001). Likewise, Kohler et al 7 studied 234 chil- dren between the ages of 2 and 18 years and found that the risk of OSAwas 3.5 times greater with each standard deviation in- crease in BMI z score in children over 12; no association was found in children under 12. In this study, male sexwas a strong predictor of OSA sever- ity. In someprevious studies of OSA inyoung children,male sex has been shown to correlate with severe OSA. 2,19,20 However, there are also multiple studies that failed to find a correlation betweenmale sex andOSA severity in children. 17,18 While there are only a few studies on predictors of OSA severity in adoles-

(Reprinted) JAMA Otolaryngology–Head & Neck Surgery May 2017 Volume 143, Number 5

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