Factors influencing compliance with continuous positive airway pressure ventilation in obstructive sleep apnea syndrome

Bulgular: Ortalama yaş 52.2 ± 12.3 yıl idi. Hastaların %71 (n= 77)’i cihazı temin etmişti. Cihazı temin eden ve etmeyenler arasında cinsiyet, yaş, medeni durum, eğitim seviyesi, semptomlar, eşlik eden hastalıklar ve sosyal güvenlik açısından fark yoktu (p> 0.05). İki grup arasında Epworth uykululuk ölçeği (ESS) ve apne hipopne indeksi (AHİ) de benzerdi. Günlük ortalama cihaz kullanımı 6.3 ± 2.3 saat idi. Cihaz kullanım uyumunun yaş, cinsiyet, eğitim düzeyi, eşlik eden hastalıklar, ESS skoru, AHİ, hava yolu pasaj ölçümleri, nemlendirici varlığı ve cihazla ilgili eğitim verilmesinden etkilenmediği tespit edildi (p> 0.05). Hasta (p= 0.057) ve yatak partnerinin (p= 0.001) cihazla ilgili memnuniyetinin cihaz uyumunu artırdığı tespit edildi.


INTRODUCTION
Obstructive sleep apnea syndrome (OSAS) is a disease with repeated apneic events and oxygen desaturation episodes which affects multiple systems (1,2).Continuous positive airway pressure (CPAP) ventilation is the leading treatment option in OSAS however compliance with the device affects treatment success (1).Several approaches including use of different device modalities and heated humidification have been undertaken to increase treatment compliance (3)(4)(5).However, the available data concerning impact of upper airway dimensions on treatment compliance is lacking.Therefore, we aimed to evaluate impact of upper airway dimensions and possible factors influencing patient compliance with CPAP usage in OSAS.

Patients
Study population consisted of patients admitted to Sleep Laboratory during June 2006 and June 2008.Subjects older than 18 years of age who were prescribed a device for OSAS were included.The study protocol was approved by University Ethics Committee.

Data Collection
Sleep studies were performed according to the guidelines of American Academy of Sleep Medicine (6).Apnea hypopnea index (AHI) was total number of apneas or hypopneas per hour.Epworth sleepiness scale (ESS) score were recorded for each patient (7).A questionnaire was prepared including information about the time of the device procurement, the type of the device and mask, the duration of usage, problems involving the device, satisfaction status, patients bed partner's opinion about the device.The questionnaire was filled out by telephone interview between June 2009 and November 2009.Lateral skull radiographs from patient files were obtained for each patient.Each radiograph was taken with the patient standing in neutral head position after swallowing.C2 vertebrae level was accepted as a landmark for airway calibre measurements.Airway calibres were obtained from the level of C2 vertebrae and narrowest airway passage.Neck and waist circumference was measured and body mass index (kg/m2 ) was calculated for each patient.

Statistical Analysis
Data was analyzed with using Statistical Package for Social Science 9.0 computer software.Comparisons between groups were performed by chi square and student's t test.p< 0.05 was accepted as significant.

RESULTS
The total number of patients who had been prescribed CPAP was 140.Of these patients, 77% (n= 108) were attained by telephone for assessment of compliance.Seventy two of the subjects were male and 88.9% (n= Introduction: Positive pressure ventilation is considered first line therapy in obstructive sleep apnea syndrome however compliance is limited by various factors.We aimed to investigate possible factors influencing compliance.

05). No difference was detected between these two groups of patients in view of Epworth sleepiness scale (ESS) and apnea hypopnea index (AHI). Mean duration of device usage was 6.3 ± 2.3 hours. The device use compliance was not affected by any of the following factors: age, gender, level of education, co-morbid diseases, ESS score, AHI, airway passage measurements, application of humidification and education concerning the device (p> 0.05).
Patient (p= 0.057) and bed partners (p= 0.001) satisfaction about the device yielded higher compliance rates.

Conclusion: Factors influencing compliance rates in obstructive sleep apnea syndrome seems to be related to satisfaction about the device use however upper airway morphology measured with C2 vertebrae level and narrowest airway passage has no impact on treatment compliance.
Key Words: Lateral skull radiography, upper airway, sleep disordered breathing.96) were married.Mean age was 52.23 ± 12.37 years.Mean airway diameters at C2 vertebrae level in males and females were 11.36 ± 3.00 cm, and 12.35 ± 3.16 cm, respectively (p= 0.23).The narrowest airway passage measurements were 9.09 ± 2.45 cm, in males and 10.05 ± 2.56 cm in females (p= 0.15).Device procurement rate was 71.3% (n= 77) while 70% of male subjects (n= 57) and 74.1% (n= 20) of female subjects obtained their device (p= 0.71).Characteristics of patients with respect to device procurement are shown in Table 1.Seventy two percent of married subjects and sixty seven percent of single subjects had obtained their device (p= 0.74).There were 13 illiterate subjects in the study population (12%) however educational status was not a factor influencing device procurement (61.5% for illiterates vs 72.6% for literates, p= 0.51).Regarding complaints concerning snoring, daytime sleepiness, witnessed apnea, dyspnea or headache we did not detect differences between these two groups of patients (p> 0.05).Co-morbid diseases were not statistically different with respect to device procurement.Reasons for not procuring devices are shown in Table 2.
Fifty three of 77 patients who obtained devices were current users.Mean daily duration of device use was 6.26 ± 2.26 hours and mean total duration of device usage was 9.44 ± 6.66 months.Characteristics of patients with respect to compliance are presented in Table 3. Sixty seven percent of patients using nasal mask and fifty seven percent of those patients who had full face mask were still using their devices (p= 0.68).Baseline ESS score in current device users was 11.59 ± 5.16 and decreased to 5.48 ± 4.73 with treatment (p= 0.00).We did not detect any difference between marital status and current device usage (p> 0.05).Sixty three percent of illiterates and 64% of literates were still using their devices (p> 0.05).We did not detect difference between sleep apnea symptoms, OSAS severity, co-morbid conditions and device usage (p> 0.05).Humidifier was present in 68.8% (n= 33) of current device users while

DISCUSSION
We found that factors influencing compliance with positive airway pressure ventilation among subjects with OSAS were mainly related to the satisfaction rate of patients and their bed partners.It has been revealed that device satisfaction enhances CPAP use regularly (8).A previous study indicated improvement of ESS score, anxiety and depression scores after CPAP usage and concluded that significant benefits in health status in both patient and partner have a positive correlation with device usage (9).A study revealed that half of the bed partners of patients with sleep disordered breathing were disturbed by snoring (10).It was also shown that bed partners of this patient population had worse sleep efficiency, increased arousals and a greater percentage of light sleep (11).Other studies showed that CPAP therapy improved bed partner's sleep quality, subjective sleepiness, mood and quality of life independent from the duration of the treatment (12)(13)(14)(15)(16).A pilot study which evaluated treatment adherence in married men revealed that it was related to the frequency with which his partner sleeps with him (17).
We did not find any relationship between airway passage measurements and device use.Craniofacial morphology in OSAS has been widely studied however there is no data regarding its relationship with compliance to positive pressure ventilation device use.A study evaluating craniofacial phenotyping revealed that neck, waist and body mass index measurements were higher in patients with OSAS while a correlation exists between OSAS severity and neck perimeter (18).
Another study revealed that hyoid bone had a low position in OSAS patients in lateral cephalogram (19).A study evaluating role of craniofacial structures in predicting optimal CPAP pressures in OSAS patients sho-wed that posterior airway space was not different between control and patient group (20).In our study there was no correlation between neck size and gender as well as upper airway diameter measurements.Tsai et al. demonstrated that male patients with risk factors such as increased neck size, inferiorly positioned hyoid bone and greater anterior lower facial height are likely to have more severe type OSAS.Posterior facial height and anteriorly positioned hyoid bone were risk factors related to the severity of OSAS in female patients (21).
We found that device procurement did not take place in around a quarter of our patients.In another study this rate was detected as 31% (8).We found that 68.8% of our study population was regularly using their devices.The compliance rate in the present study was higher than a previous study by Wolkove et al. (68% vs. 54%) (8).The reason for this could be due to a longer period of follow up in their study after the diagnosis (64 ± 3.7 months).It has been previously suggested that older individuals might have poor compliance rate however, we found no statistically significant difference between age distribution of patients who were using their device or not (52.04 ± 12.32 vs. 50.56± 13.69; respectively) (22).
Co-morbidity was not found to be related to the compliance rate of CPAP.Similarly symptoms concerning OSAS such as snoring, daytime sleepiness and apnea had no effect on compliance.Our results showing that humidification did not add to the compliance rates were also compatible with previous data (5).
We did not find association between disease severity which was calculated with AHI and device compliance.This is in accordance with a previous study as disease severity has not been found to be related to compliance rates (23).In a study comparing regular CPAP users with irregular users, the tendency of CPAP usage was highest among severe sleep apneic patients (23).In the present study, sleepiness state which was evaluated with ESS score was decreased after device use, compatible with literature findings (8,(24)(25)(26).
There are some limitations to the present study: the data used to evaluate compliance rate were subjective.It would be better to evaluate satisfaction status of patients and bed partners with quality of life questionnaires.We were able to interview three fourths of our patient population mainly because of insufficient contact information.We could not evaluate the effect of different masks and devices on the compliance rate because of the limited number of cases.
In conclusion we found that gender, lateral cervicofacial dimensions, marital status, educational status, daytime sleepiness state, AHI, co-morbid diseases and existence of humidifier have no effect on device compliance.This is the first study evaluating the impact of lateral skull radiography findings on compliance.Future studies focusing on craniofacial morphometry and device compliance in larger populations are necessary.The satisfaction of the patients and their partners seem to be the main factors affecting compliance with positive pressure ventilation devices.In order to benefit from CPAP treatment, compliance should be increased, thus bed partner motivation is necessary for better compliance.
subjects who have received the prescribed devices and who have not (p> 0.