Newswise — Health officials, social scientists, and parents all agree that childhood obesity, defined as an age and gender-specific body mass index (BMI) greater than the 95th percentile, has reached epidemic proportions, increasing from six to 14 percent of American children in the last 25 years. Obstructive sleep apnea (OSA), characterized by recurrent interruptions of breathing during sleep due to temporary obstruction of the airway by lax, excessively bulky, or malformed pharyngeal tissues (soft palate, uvula, and sometimes tonsils), occurs frequently in obese children who have enlarged tonsils. The prevalence of OSA in these children appears to be between 30 and 40 percent, a rate that compares unfavorably with the general pediatric population in which the prevalence is only one percent. The high prevalence of OSA in obese children is associated with a decrease in the cross-sectional area of the pharynx. This condition can have many causes, including the narrowing of the upper airway caused by fatty tissue adjacent to the pharynx. In addition, there may be external compression of the upper airway by fat in the subcutaneous tissues of the neck. Enlarged tonsils and adenoids in obese children further decrease the cross-sectional area of the pharynx.
Therefore, it is not surprising that in the last two decades, the principle reason for adenotonsillectomy in children has changed from recurrent infection of the tonsils to OSA. Accordingly, increasing obesity in children with associated OSA implies that an increasing number of these children will present for adenotonsillectomy.
But does this surgical procedure actually produce a significant change in the obese child's life? A new study has examined changes in the physiological parameters of sleep and in quality of life after adenotonsillectomy for OSA in obese children. Past research has focused on whether an adenotonsillectomy produces an improvement in sleep and quality of life in the general population of children with OSA. This research has a different goal—to establish the outcome of surgery for OSA in obese children.
The authors of "Adenotonsillectomy for OSA in Obese Children" are Ron B. Mitchell MD, from the Department of Surgery and Pediatrics, and James Kelly PhD, Department of Surgery, from the University of New Mexico Health Sciences Center, Albuquerque, NM. Their findings will be presented September 23, 2003 at the American Academy of Otolaryngology—Head and Neck Surgery Foundation http://www.entnet.org Annual Meeting & OTO EXPO, Orlando, FL, being held September 21-24, 2003.
Methodology: The study had the participation of children with a sleep disturbance who were shown to have OSA by polysomnography (a sleep study, or the simultaneous and continuous monitoring of relevant normal and abnormal physiologic activity during sleep) and an age- and gender-specific BMI greater than the 95th percentile were included in the study. The caregivers of these children were asked to complete an Informed Consent Document before enrolling the children in the study. Exclusion criteria included: 1) children younger than three or older than 18 years of age; 2) children who had a previous adenotonsillectomy; 3) children with craniofacial syndromes, neuromuscular disease, developmental delay or psychiatric disorders; 4) children with a respiratory distress index (RDI), a measure of sleep disturbance obtained from polysomnography, less than a reading of five. The effectiveness of adenotonsillectomy for OSA was evaluated using polysomnography and the OSA-18 Quality of Life Survey (OSA-18). All study participants underwent full-night polysomnography (PSG) to document OSA. The RDI, defined as the average number of apneas and hypopneas per hour of sleep, was used for diagnosis of OSA. A sleep medicine physician interpreted the results of polysomnography. Polysomnography findings were classified as: mild (RDI > 5 < 10); moderate (RDI > 10 < 20); or severe (RDI > 20). Children with an RDI > 5 were included in the study.
The OSA-18 survey comprises 18 items in five domains of sleep disturbance, physical suffering, emotional distress, daytime problems and caregiver concerns. A point scale is used ranging from 1 (= none of the time) to 7 (= all of the time) to grade the relative severity of the problem addressed in each item. The total score and the domain scores were recorded. Using these two measuring devices offered the researchers the opportunity to detect a clinically significant change in health-related quality of life based on OSA-18 total score and in the physiological parameters of sleep as measured by RDI.
Caregivers were asked to complete the first OSA-18 survey prior to polysomnography. Children with OSA subsequently underwent a monopolar adenotonsillectomy with cauterization. Post-operative polysomnography was performed on all children enrolled in the study within a mean interval of 5.6 months. Caregivers were asked to complete the OSA-18 survey a second time within a mean interval of 2.4 months after surgery.
Results: A total of 46 children were enrolled in the study. Eight of these children were lost to follow-up, four did not have post-operative PSG, two did not undergo surgical therapy, and the caregivers for two children did not complete the post-operative OSA-18 survey. As a consequence, the study population included 30 children. Of these, 26 of the children were male. The mean age of the children at the time of inclusion in the study was 9.3 years, and the range was three to 17.2 years. The most common other disorders found in the subjects were asthma in 13 children and allergies in 12 children. The mean preoperative BMI was 28.6 (range 19.2"47.1) and the mean post-operative BMI was 27.9 (range 17.8" 27.9).
The mean period of follow-up was 5.6 months. Preoperatively, 24 children (79 percent) had moderate to severe OSA and 6 children (21 percent) had mild OSA. Post-operatively, 11 children (37 percent) had moderate to severe OSA, five children (17 percent) had mild OSA and 14 children (46 percent) had no evidence of OSA.
Caregivers reported improvement in their children after surgery in all domains of the OSA-18 survey including sleep disturbance, physical suffering, emotional distress and daytime problems. Caregiver's concerns were also reduced after surgery. The mean interval between surgery and the post-operative OSA-18 survey in the present study was 4.1 months. The findings proved that the dramatic improvement in quality of life seen after adenotonsillectomy for OSA in the general population of children also occurs in obese children. This improvement persists for at least 4 months after surgery. It is logical to propose that correcting OSA would lead to increased activity and weight loss. The children enrolled in the present study also did not show a significant change in BMI after surgery, confirming past research efforts which found that adenotonsillectomy improves OSA but does not lead to weight reduction.
Conclusion: This is the first prospective study of improvements in PSG and quality of life after adenotonsillectomy in obese children with OSA. Obese children with OSA who undergo adenotonsillectomy show a significant improvement in RDI and in quality of life over period of several months with no change in BMI. However, OSA does not resolve in the majority of obese children after surgery.
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