The Natural History of Childhood Obstructive Sleep Apnea

Abstract

Source: Chan KC, Au CT, Hui LL, et al. How OSA evolves from childhood to young adulthood: natural history from a 10-year follow-up study. Chest. 2019; 156(1): 120– 130; doi: 10.1016/j.chest.2019.03.007Investigators from the Chinese University of Hong Kong conducted a prospective longitudinal cohort study to assess the natural history of obstructive sleep apnea (OSA) in children through early adulthood. Children who were 6–13 years old and did not have cardiovascular, renal, or neuromuscular disease; chromosomal abnormalities; or acute illness within 2 weeks of recruitment were enrolled between 2003 and 2005. At enrollment, parents of child participants completed (a) a validated sleep symptom survey, which included snoring frequency; (b) a medical history questionnaire, which included history of allergic rhinitis and asthma, as well as treatment received for sleep-disordered breathing; and (c) a demographic survey. All child participants also underwent an assessment of their tonsil and adenoid size, had their BMI measured, and underwent nocturnal polysomnography (PSG) at enrollment. Investigators then invited this cohort of participants to participate in a follow-up assessment 10 years later. Study activities at follow-up were similar to those at enrollment.The primary outcome was complete remission of childhood OSA, defined as an obstructive apnea hypopnea index (OAHI) of <1 event per hour at follow-up among those with OAHI ≥1 event per hour at baseline as measured with PSG. A secondary outcome was incidence of OSA, defined as OAHI ≥5 events per hour at follow-up among those having OAHI <5 events per hour at baseline. The investigators assessed the association of demographics, medical history characteristics, height and weight, and tonsil and adenoid size with each outcome by using log-binomial regression.Of 619 participants at baseline, 243 (39%) completed follow-up study activities. The mean age of participants at follow-up was 20.2 years. Among participants who had OAHI >1 event per hour at baseline, 30% had complete remission at follow-up. Among those who had OAHI <5 events per hour at baseline, 24% had OAHI ≥5 events per hour at follow-up. Male participants were significantly less likely to have complete remission and more likely to have incident OSA at follow-up. Participants with an increase in BMI since baseline were significantly more likely to have incident OSA at follow-up.The investigators conclude that a minority of children have complete resolution of their childhood OSA at 10 years and that an increase in BMI is associated with new-onset OSA in adulthood.Dr Lesser has disclosed no financial relationship relevant to this commentary. This commentary does not contain a discussion of an unapproved/investigative use of a commercial product/device.OSA affects 3%–5% of children and occurs even more commonly in adulthood.1 Neurobehavioral, cardiovascular, and metabolic consequences of the disease are well described.2 When available, PSG is recommended to diagnose OSA in children with snoring and suggestive signs or symptoms.2 The OAHI, defined as the average number of obstructive apneas and partial obstructive apneas (hypopneas) per hour of sleep, is the main PSG outcome measure used to diagnose and measure OSA. Management options for childhood OSA include tonsillectomy, medications for upper airway inflammation, watchful waiting, weight loss, and/or positive airway pressure therapy. Knowledge of the natural history of childhood OSA aids clinicians in discussing disease implications and treatment options with families.Compared to prior studies of the natural history of childhood OSA, the current investigation included a significantly larger cohort of patients with OSA and used a somewhat longer follow-up, spanning into early adulthood. The availability of detailed longitudinal data to assess risk factors for OSA, such as obesity, asthma, and allergic rhinitis, is another strength. The findings are somewhat limited by the number of patients lost to follow-up (61%); however, baseline characteristics comparing follow-up participants with nonparticipants were not significantly different. Although the overall cohort size was relatively large, <10% of participants had moderate to severe OSA at baseline or follow-up. Thus, the authors’ findings may be less applicable to this important subgroup at highest risk for OSA sequelae. The group with persistent OSA had a decrease in percentage overweight at follow-up—a finding that may not be mirrored in US populations.3,4 A lower remission rate also was seen compared to those in US studies,4 suggesting the pathophysiological nature of OSA is not related to obesity alone.A significant number of participants were identified as having OSA and were left untreated (67%) based on family preference. The study was not designed to identify sequelae, if any, of this lack of treatment. The question remains as to the implications of expectant management even in those likely to experience resolution of OSA. This issue is even more complicated by the challenges of adhering to long-term nonsurgical treatments for OSA.Increased age at diagnosis, male sex, and obesity define risk factors for persistent OSA into early adulthood.