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.