Compared with watchful waiting, early adenotonsillectomy did not significantly improve attention or executive function as measured by neuropsychological testing in school-aged children with obstructive sleep apnea syndrome, according to a new report.
The findings were published online May 21 in the New England Journal of Medicine and simultaneously reported at the annual meeting of the American Thoracic Society.
However, early surgery did markedly improve polysomnographic abnormalities, as well as parent- and teacher-reported measures of behavior, executive function, and sleep symptoms, compared with watchful waiting, said Dr. Carole L. Marcus, director of the sleep center at Children’s Hospital of Philadelphia, and her associates.
Dr. Carole L. Marcus
"We observed no significant difference between the two groups in the change from baseline to follow-up in our primary outcome, the attention and executive-function score of the NEPSY [Developmental NeuroPsychological Assessment]; thus our trial is a negative one. However, other tests showed evidence of changes in behavior," noted Dr. Marcus and her associates in the Childhood Adenotonsillectomy Trial (CHAT).
Previous studies examining cognitive and behavioral outcomes after adenotonsillectomy for obstructive sleep apnea syndrome "have been limited by small samples, lack of randomization or appropriate controls, heterogenous study groups, and sole reliance on parent questionnaires rather than including neuropsychological testing," the investigators said.
In contrast, CHAT involved 453 children aged 5-9 years treated at seven academic sleep centers, who underwent standardized polysomnographic assessments and extensive testing via the Developmental Neuropsychological Assessment (NEPSY); Behavior Rating Inventory of Executive Function (BRIEF); Differential Ability Scales (DAS), which measures general intellectual functioning; Conners’ Rating Scale Revised (CRS-R); Pediatric Sleep Questionnaire sleep-related breathing disorder scale (PSQ-SRBD); Epworth Sleepiness Scale modified for children; Pediatric Quality of Life Inventory (PedsQL); and the Obstructive Sleep Apnea–18 assessment tool that measures disease-specific quality of life.
The children were randomly assigned to undergo adenotonsillectomy within 1 month (226 patients) or to be followed with watchful waiting (227 control subjects), and were formally assessed 7 months later. Demographic and clinical characteristics were well-balanced between the two study groups at baseline, and cognitive and behavioral scores were close to population means. A similar number of children in each group used nasal glucocorticoids or montelukast for allergic rhinitis or asthma.
Approximately half of the children in each group were overweight or obese.
The primary efficacy outcome was change in attention and executive-function score on the NEPSY. These scores improved more in children who underwent adenotonsillectomy than in the controls, but the difference did not reach statistical significance.
However, outcomes were significantly better with surgery than with watchful waiting on measures of obstructive apnea-hypopnea, oxygen desaturation index, hypercapnia, sleep arousal index, and percentage of sleep time in light sleep. This last measure is an indication of improved sleep continuity.
In particular, many more children who underwent early adenotonsillectomy (79%) achieved normalization of the obstructive sleep apnea syndrome, compared with control subjects (46%) (N. Engl. J. Med. 2013 May 21 [doi:10.1056/NEJMoa1215881]).
Adenotonsillectomy also improved outcomes to a significantly greater degree than did watchful waiting on the Conners’ Rating Scale assessing restlessness, impulsiveness, and emotional lability, as well as on all other measures of behavior and quality of life. The effect sizes were in the moderate-to-large range, indicating that the changes were clinically significant.
These benefits were noted in all subgroup analyses, most importantly in both obese and nonobese children. Obese children and children with more severe apnea symptoms showed larger absolute improvements after surgery than did other study subjects.
However, normalization of symptoms was less likely to occur in black children than in those of other races, regardless of treatment assignment. Obstructive sleep apnea has previously been reported to be more severe in black children, as it was in this study population. Black subjects in this study also showed less improvement in parent- and teacher-reported measures after adenotonsillectomy, relative to children of other races.
"The reasons for this racial disparity are unclear. Possible explanations include differences in parents’ expectations, coping mechanisms, or perceptions of their child’s behavior and the presence of risk factors for behavioral problems unrelated to the obstructive sleep apnea syndrome," Dr. Marcus and her associates said.
Regarding adverse effects, the number of serious events was similar between the two study groups. Eight events were related to perioperative complications, but three of these occurred in children assigned to the watchful waiting group who later crossed over to the surgery group.
Overall, the rate of perioperative complications was low, and the only treatment failures in this study occurred in the watchful waiting group. "Thus, this trial supports the overall safety of both early adenotonsillectomy and watchful waiting, but suggests the need for clinical monitoring of children who are being treated conservatively," the researchers said.