ORIGINAL RESEARCH Outcome of adenotonsillectomy for obstructive sleep apnea in obese and normal-weight children Ron B. Mitchell, MD, and James Kelly, PhD, St Louis, MO; Albuquerque, NM OBJECTIVES: 1) To evaluate the relative severity of obstruc- tive sleep apnea (OSA) in obese and normal-weight children; 2) to compare changes in respiratory parameters after adenotonsillec- tomy in obese and normal-weight children. STUDY DESIGN AND SETTING: Prospective controlled trial that included children aged 3 to 18 years. All study participants underwent pre- and postoperative polysomnography. RESULTS: The study population included 33 obese children and 39 normal-weight controls. Preoperatively, the median ob- structive apnea-hypopnea index (AHI) was 23.4 (range 3.7-135.1) for obese and 17.1 (range 3.9-36.5) for controls (P  0.001). Postoperatively, the AHI was 3.1 (range 0-33.1) for obese and 1.9 (range 0.1-7.0) for controls (P  0.01). Twenty-five obese children (76%) and 11 controls (28%) had persistent OSA. CONCLUSION AND SIGNIFICANCE: AHI scores are higher in obese than in normal-weight children with OSA. Both groups show a dramatic improvement in AHI after adenotonsillectomy, but persistent OSA is more common in obese children. © 2007 American Academy of Otolaryngology–Head and Neck Surgery Foundation. All rights reserved. T he prevalence of obesity in children has increased markedly in the last two decades. Approximately 30 percent of children in the United States are overweight at the present time, and 16 percent of them are considered obese. 1 There is also increasing evidence that obesity in children has become a global problem. 2,3 Although obese children have a number of health concerns, obstructive sleep apnea (OSA) is common among them and is known to lead to a decrease in their quality of life. 4 A dysfunction in neuromotor control of the pharynx is thought to be the underlying cause of OSA in children, 5 but adenotonsillar hypertrophy further narrows the airway and exacerbates OSA. Consequently, adenotonsillectomy im- proves OSA in the majority of children. 6 In obese children, however, a number of factors in addition to adenotonsillar hypertrophy contribute to a high prevalence of OSA and may compromise surgical therapy. Adipose tissue immedi- ately adjacent to the pharynx may decrease the cross-sec- tional area of the upper airway, 7 and there may be external compression of the pharynx by fat in the subcutaneous tissues of the neck. 8 A decrease in the compliance of the chest wall and the displacement of the diaphragm may also lessen the volume of the lungs. Therefore, it is not surpris- ing that the prevalence of OSA in obese children is 25 to 40 percent. 9 Previous studies of the outcome of adenotonsillectomy for OSA in obese children have been limited by the lack of data from both pre- and postoperative polysomnography. These data are necessary to provide an objective evaluation of the outcome of surgery. 10 In the present study, polysomnography was used to compare the outcome of adenotonsillectomy for OSA in obese and normal-weight children. The goal was to provide quantitative data on the relative effectiveness of ad- enotonsillectomy for OSA in obese children. METHODS Children referred to the pediatric otolaryngology service of the University of New Mexico Hospital with a sleep distur- bance were evaluated for inclusion in the study. Institutional review board approval was obtained from the University of New Mexico, and caregivers of children signed an informed consent document prior to enrollment. All children consid- ered for enrollment underwent polysomnography. Exclu- sion criteria included: 1) children younger than three or older than 18 years; 2) children who previously had an adenotonsillectomy; 3) children with craniofacial syn- dromes, neuromuscular disease or developmental delay; and 4) children with an obstructive apnea-hypopnea index (AHI)  2. Demographic information was collected for both caregiver and child. The age- and gender-corrected body mass index (BMI) was calculated for each child using established guidelines and children were divided into four groups as follows: group 1, underweight (BMI less than or equal to the 5th percentile); group 2, normal (BMI greater than the 5th percentile but less than the 85th); group 3, at risk for obesity (BMI greater than the 85th percentile but less than the 95th); group 4, obese (BMI greater than or equal to the 95th percentile). Children in group 4 were considered obese and were compared with the normal-weight children of group 2. Tonsils were graded according to the scheme proposed by Brodsky 11 : (1) small tonsils confined to the tonsillar Received December 22, 2006; accepted March 15, 2007. Otolaryngology–Head and Neck Surgery (2007) 137, 43-48 0194-5998/$32.00 © 2007 American Academy of Otolaryngology–Head and Neck Surgery Foundation. All rights reserved. doi:10.1016/j.otohns.2007.03.028