Discussion
This study is the first to describe the number and characteristics of children with OSA-I and OSA-II treated with long term CPAP/NIV in France. Our results show that 6% and 10% of children had OSA-I and OSA-II, respectively, with the majority being treated with CPAP. Both groups were comparable except for age with OSA-II patients being older.
CPAP/NIV is not a first line treatment for severe OSA-I and OSA II. Indeed, these treatments are reserved for patients who have severe persistent OSA after failure of all other therapeutic options (4, 5, 10). Drug-induced sleep endoscopy (DISE) is recommended in case of residual OSA after adeno-tonsillectomy in children with OSA-I to identify other persistent obstructive sites that may be cured by a complementary, targeted upper airway surgery (11, 12). Orthodontic treatment may be an option for selected patients (4, 5). In children with OSA-II, weight loss represents the first line treatment, even if a sufficient weight loss to correct or improve OSA is difficult to obtain. DISE is also indicated in these patients, mainly because of the high prevalence of hypertrophy of the lingual tonsils, beside the hypertrophy of the tonsils (4, 5). In any case, the decision of CPAP/NIV should be taken by a pediatric multidisciplinary team, after having explored all other alternative therapeutic options (10).
Six and 10% of children treated with long term CPAP/NIV in France on June 2019 had OSA-I and OSA-II, respectively. The majority of epidemiological studies worldwide which analyzed the characteristics of children treated with long term CPAP/NIV showed that nearly all children had an underlying disease (10). Some studies gave no information on patients with OSA-I or OSA-II (13-16), whereas other studies gave information on patients with obesity without specifying if these patients had OSA-II or syndromic obesity (17-19). Obese children represented 19% of the cohort in the studies by Castro-Codesal et al . (17) in Canada and Tsang et al . (19) in Hong-Kong, and 7.4% in a survey by Leske et al. (18) in Argentina. A recent study in Finland identified 5 children out of 93 who were treated with long term CPAP/NIV for OSA-II (20). The only study which reported long term CPAP/NIV in children with OSA-I was the study by Tsang et al.(19) in Hong Kong with 45% of 114 children having OSA-I. However, no information was available on the selection of the patients and the initiation criteria. Our data are thus one of the first nation-based data focusing on the prevalence and characteristics of patients with OSA-I and OSA-II treated with long term CPAP/NIV. As standardized protocols are used in France for the management of children with OSA-I and OSA-II, the prevalence of 6% for OSA-I and 10% for OSA-II seems realistic (21-23).
The fact that the patients with OSA-I were younger than those with OSA-II may be explained by the pathophysiology of OSA-I and OSA-II. Indeed, OSA-I is related to adeno-tonsillar hypertrophy which peaks between the age of 3 to 6 years (24), whereas obesity predominates during pre-adolescence and adolescence. Patients with OSA-I have a tendency to improve with age, while a sufficient weight loss is rarely obtained in obese children with severe OSA to be weaned from CPAP (25). Consequently, patients with OSA-II were treated for a longer time than patients with OSA-I probably because they are less prone to be weaned from CPAP/NIV. The objective adherence was quite good, with a higher adherence in patients treated by NIV, and comparable between both groups. This is in contradiction with the literature with numerous studies showing a low CPAP/NIV adherence in obese patients as compared to non-obese patients (26, 27). This may be explained by the close follow-up and systematic therapeutic education of the children treated with CPAP/NIV in France (9).
Concerning the investigations performed before the CPAP/NIV initiation, only half of the patients had an overnight PtcCO2recording. PtcCO2 recording is highly recommended in children with a suspicion of OSA but not always available in every center (28). Like adults, children with obesity are at risk of nocturnal hypoventilation and should thus ideally have a PtcCO2recording. Indeed, the persistence of nocturnal alveolar hypoventilation despite optimal CPAP treatment is an indication to switch for NIV (10, 28). Of note, all the obese patients who had no PtcCO2recording were treated with CPAP. It is thus possible that some patients with OSA-II had non-diagnosed alveolar hypoventilation and were thus consequently not treated optimally.
The majority of patients were treated with a standard device. The proportion of patients treated with a standard device was higher in patients with OSA-II as compared to patients with OSA-I. This may be explained by the older age and thus the greater weight in patients with OSA-II as compared to patients with OSA-I. Indeed, in order to adequately detect the patient’s airflow, a device corresponding to the patient’s weight should be used, with thus younger children requiring more often a level II or level III device (10, 29). The majority of the patients used a nasal interface. Very few OSA-II patients used nasal prongs (n=6), which may be explained in part by the young age of the patients.
The mean CPAP level was slightly but significantly higher in patients with OSA-II as compared to patients with OSA-I. Mean inspiratory and expiratory pressures tended to be higher in patients with OSA-II treated by NIV. This may be explained by the older age but also the presence of obesity requiring a higher positive airway pressure to maintain airway patency.
The main limitation of this study is the lack of information on the body mass index and the AHI and nocturnal gas exchange values. As this study is a sub-analysis of a national study, this information is unfortunately not available.
In conclusion, this study is the first to provide clinical data on an important and potentially increasing population of children treated with long term CPAP or NIV. Patients with OSA-I and OSA-II represented 6% and 10% of a French national cohort, respectively. Patients were mainly initiated on CPAP/NIV on a high AHI and treated with CPAP. Objective compliance was quite good and comparable between the two groups. A prospective study, taking in account the body mass index but also other clinical data such as waist circumference, the initiation criteria, and the duration and weaning of CPAP/NIV is worth to be performed in the future.