September 2019 HSC Section 1 Congenital and Pediatric Problems

Research Original Investigation

Predictors of Obstructive Sleep Apnea Severity in Adolescents

Table 1. Baseline Characteristics for Normal-Weight, Overweight, and Obese Adolescents a

No. (%)

Normal Weight (n = 31)

Absolute Difference (95% CI) b

Overweight (n = 45) 14.6 (1.8) 23 (51.1) 22 (48.9) 16 (35.6) 6 (13.3) 19 (42.2) 6 (13.3) 18 (40.0) 13 (28.9) 17 (37.8) 12 (26.7) 1 (2.2)

Obese (n = 148) 14.7 (1.6) 77 (52.0) 85 (57.4) 43 (29.1) 19 (12.8) 61 (41.2) 12 (8.1) 47 (31.8) 45 (30.4) 50 (33.8) 38 (25.7) 15 (10.1) 1 (0.7)

Total (n = 224)

Variable

Age, mean (SD), y

14.6 (1.7)

14.2 (1.7) 19 (61.3)

0.6 (−0.1 to 1.2)

Male

119

9 (−10 to 29)

Ethnicity

Hispanic

123 (55.0) 68 (30.4) 30 (13.4) 91 (41.0) 19 (8.4) 74 (33.0) 68 (30.4) 77 (34.4) 61 (27.2) 18 (8.0) 3 (1.3)

16 (51.6) 9 (29.0) 5 (16.1) 11 (35.5) 1 (3.2) 9 (29.0) 10 (32.3) 10 (32.3) 11 (35.5) 1 (3.2)

9 (−8.0 to 25) 10 (−10 to 30)

African American

White Other

3.0 (−11 to 17) 3.0 (−4.0 to 9.0)

Allergies Reflux Asthma Tonsil size 1

10 (−20 to 30) 10 (−2.0 to 22) 11 (−11 to 33)

3.0 (−18 to 25) 6.0 (−16 to 27) 10 (−9.0 to 28) 10 (5.0 to 15)

2 3 4

Abbreviations: AHI, apnea hypopnea index; BMI, body mass index (calculated as weight in kilograms divided by height in meters squared). a Normal weight, BMI 5% to 85%; obese, BMI 95%; overweight, BMI 85% to 95%. b Mean difference of continuous variable and percent difference for categorical variables.

0 (0.0)

3 (6.7)

OSA diagnosis No OSA

71 (32) 51 (23) 27 (12) 75 (33)

16 (52)

21 (47) 10 (22)

34 (23) 33 (22) 21 (14) 60 (41)

29 (10 to 48)

Mild (AHI 1-4)

8 (26)

4.0 (−13 to 21) 8.0 (−3.0 to 18)

Moderate (AHI 5-9) Severe (AHI ≥10)

2 (6)

4 (9)

5 (16)

10 (22)

24 (6.0 to 42)

Categorical data was presented as counts with percent- ages. Continuous data was presented as mean with standard deviations (SD). To test for differences in baseline character- istics between normal weight, overweight, and obese adoles- cents, ANOVA was used for continuous variables and the Pearson χ 2 test or Fisher exact test was used for categorical variables. An analysis of variance (ANOVA) model was created to assess the correlation between each demographic/ clinical variable (sex, age, ethnicity, weight classification, etc) and the AHI. Ethnicity was modeled as a binary variable of African American race and all other races. Tonsil- lar hypertrophy was also modeled as a binary (3/4 vs 1/2 tonsillar size), as was the presence of asthma, allergic rhinitis, and GERD. Weight classification was modeled as normal weight, overweight, and obese. The statistically significant variables from the univariate analysis (weight classification and tonsillar size) were included in a multivariable model which controlled for the effects of the other variable. A similar approach was taken to assess predictors of severe OSA using a logistic regression model followed by a multivariable model that controlled for the other vari- ables that were found to be significant in the univariate model (male sex, weight classification, adenotonsillar hypertrophy). All statistics were performed with Stata statistical soft- ware (version 14, Stata Corp). Statistical significance was set at P ≤ .05.

Results A total of 625 adolescents underwent PSG over the study period. Of the initial group, 401 children were excluded from the study, resulting in a final study population of 224 patients. The most common reasons for exclusion were pre- vious tonsillectomy and adenoidectomy (163 patients), neu- rological disorders (71 patients), respiratory and/or muscu- lar abnormalities (43 patients), missing data for tonsillar size (34 patients), Down syndrome (28 patients), and cranio- facial abnormalities (20 patients). The baseline characteristics of the study population are presented in Table 1 . The mean (SD) age was 14.6 (1.7) years and 119 (53%) were male. The mean (SD) BMI was 33.4 (10.4). Most were either Hispanic or African American (191, 85.3%). A total of 148 (66.1%) were obese. Most (153 [68%]), had OSA (AHI ≥1). Normal-weight adolescents were least likely to have OSA at 48%, while obese children were most likely at 77%. Obese adolescents had the highest percentage with severe OSA (41%) and normal weight had the lowest (16%). There were no significant differences in age, sex, eth- nicity, tonsil size, or presence of reflux, asthma, or allergic rhinitis between normal weight, overweight, and obese adolescents. Table 2 presents the polysomnographic data for normal weight, overweight, and obese adolescents. There were sig- nificant differences between thehighest and lowest values that were all worst in obese and best in normal-weight adoles-

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

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