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* From the Department of Medicine & Therapeutics, Prince of Wales Hospital, Chinese University of Hong Kong, Shatin, New Territories, Hong Kong.
Correspondence to: David S. C. Hui, MBBS, FCCP, Department of Medicine & Therapeutics, Prince of Wales Hospital, Chinese University of Hong Kong, Shatin, New Territories, Hong Kong; e-mail: dschui{at}cuhk.edu.hk
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Abstract |
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 TOP Abstract IntroductionMaterials and MethodsResultsDiscussionReferences |
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Design: A randomized, controlled, parallel study of basic vs augmented CPAP education and support.
Setting: A university teaching hospital.
Patients: A total of 108 OSA patients randomized into basic-support (BS) and augmented-support (AS) groups.
Interventions: Patients in the BS group (n = 54) were given educational brochures on OSA and CPAP, CPAP education by nurses, CPAP acclimatization, and were reviewed by physicians and nurses at weeks 4 and 12. Patients in the AS group (n = 54) received more education, including a videotape, telephone support by nurses, and early review at weeks 1 and 2.
Measurements: Objective CPAP compliance, Calgary sleep apnea quality of life index (SAQLI), and cognitive function after 1 month and 3 months; and Epworth sleepiness scale (ESS) after 3 months of CPAP treatment.
Results: At 4 weeks, CPAP usage was 5.3 ± 0.2 h/night (mean ± SEM) vs 5.5 ± 0.2 h/night in the BS and AS groups, respectively (p = 0.4). At 12 weeks, CPAP usage was 5.3 ± 0.3 h/night vs 5.3 ± 0.2 h/night in the two groups, respectively (p = 0.98). There was greater improvement of SAQLI at 4 weeks (p = 0.008) and at 12 weeks (p = 0.047) in the AS group. There was no significant difference between BS and AS groups in terms of improvement of ESS and cognitive function.
Conclusion: Augmentation of CPAP education and support does not increase CPAP compliance, but leads to a greater improvement of quality of life during the reinforced period.
Key Words: compliance • continuous positive airway pressure education • obstructive sleep apnea • outcome
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Introduction |
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TOPAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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consequence of OSA, due to sleep fragmentation triggered by repetitive episodes of partial or complete upper-airway obstruction.2 Sleep fragmentation may also contribute to impaired cognition or altered mood,3 and patients are prone to accidents at work or while driving,4 with poor work and social functioning.5
Introduced by Sullivan et al6 in 1981 as a pneumatic splint to prevent collapse of the upper airway, nasal continuous positive airway pressure (CPAP) has remained the standard treatment for OSA, and several randomized placebo-controlled trials have shown significant improvement of symptoms, quality of life, and daytime function in patients treated with nasal CPAP.7 8 9 10 11 CPAP compliance, however, has been variable in different studies, ranging from 2.8 to 6.0 h/night in new CPAP users.7 8 9 10 11 12 13 14 In a prospective study of 23 newly diagnosed OSA patients commencing CPAP treatment, we previously reported an objective CPAP compliance rate of 64% and 67% at 1 month and 3 months, respectively,15 with acceptable compliance as defined by Kribbs et al12 as CPAP use of at least 4 h/d for at least 70% of the nights per week.
In this study, we would like to explore if augmentation of CPAP education and support within our resources would enhance CPAP compliance and improve treatment outcomes such as sleepiness, quality of life, and cognitive function among our OSA patients.
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Materials and Methods |
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TOPAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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Patients
From our respiratory and sleep clinic, we recruited 108
consecutive, symptomatic patients with newly diagnosed OSA. Significant
OSA was defined as apnea-hypopnea index (AHI) 
10 events/h of sleep
as shown by overnight polysomnography (Sleep Lab 1000p; Aequitron
Medical; Minnetonka, MN) plus self-reported sleepiness.
Overnight polysomnography recorded EEG, electro-oculogram, submental
electromyogram, bilateral anterior tibial electromyogram, ECG, chest
and abdominal wall movement by inductance plethysmography, and airflow
measured by a nasal pressure transducer (PTAF; Pro-Tech; Woodinville,
WA), and backed up by oronasal airflow measured with a thermistor and
finger pulse oximetry. Sleep stages were scored according to standard
criteria by Rechtshaffen and Kales.16
Apnea was defined as
cessation of airflow for > 10 s, and hypopnea was defined as a
reduction of airflow 50% for > 10 s plus an oxygen desaturation
of > 4% or an arousal. The subjects were randomized into two arms,
with group 1 receiving basic CPAP education and support and group 2
receiving augmented education and support. Our study was approved by
the Ethics Committee of the Chinese University of Hong Kong, and
appropriate informed consent was obtained from the subjects.
Study Protocols
Basic Support:
Following confirmation of significant OSA
from the overnight diagnostic sleep study, each patient was interviewed
by the physician on duty and offered a trial of nasal CPAP treatment.
Each patient was given a 10-min CPAP education program by a respiratory
nurse who explained the basic operation and care of the CPAP device and
mask. An brochure on OSA and CPAP treatment in Chinese was given to
each patient during the education session. The nurse chose a
comfortable CPAP mask from a wide range of selections for the patient,
who was then given a short trial of CPAP therapy with the AutoSet
(Resmed; Sydney, Australia) CPAP device for approximately 30 min of
acclimatization in the afternoon. Attended CPAP titration was performed
with the AutoSet auto-titrating device on the second night of the study
in our hospital, with full polysomnography. Throughout the night and
the next morning, the nurses on duty would deal with any discomfort
related to the CPAP treatment. The CPAP pressure for each patient was
set at the minimum pressure needed to abolish snoring, obstructive
respiratory events, and airflow limitation for 95% of the night, as
determined by the overnight AutoSet CPAP titration study. Several
studies have shown that automatic CPAP titration is as effective as
manual titration in correcting the obstructive respiratory events,
arousal frequency, and improving oxygenation.17
18
19
20
All
the patients were prescribed the Aria CPAP device (Respironics;
Murrysville, PA), which automatically turned on when the patients
breathed into the mask and shut off when the mask was removed. The Aria
CPAP contains a microprocessor with dual time meters recording both
machine run time and time spent at effective pressure (measured by a
mask pressure transducer recorder). The patients subsequently were
followed up by physicians and nurses at the CPAP clinic at 1 month and
3 months to deal with any problem with the CPAP device or mask fit, and
CPAP pressure was adjusted if necessary.
Augmented Support: In addition to the basic-support (BS) group, patients in the augmented-support (AS) group were given extra education on OSA and CPAP by physicians via a locally produced 15-min videotape. Our respiratory nurses would also reinforce knowledge about OSA and provide solutions for potential problems with the use of CPAP during an additional 15-min education session. The patients were reviewed early by physicians at week 1 and week 2. The respiratory nurses also followed up these patients by phone on day 1 and day 2, and at weeks 1, 2, 3, 4, 8, and 12 to help sort out any technical problem and encourage the use of CPAP.
Outcome Measurements
Prior to commencement of nasal CPAP, all patients had to go
through several measurements. These included assessment of subjective
sleepiness with the Epworth sleepiness scale (ESS), quality of life
with the Calgary sleep apnea quality of life index (SAQLI), and
psychometric tests.
The ESS21 is a questionnaire specific to symptoms of daytime sleepiness, and patients are asked to score the likelihood of falling asleep in eight different situations with different levels of stimulation, adding up to a total score of 0 to 24. The ESS has been shown to have significant correlation with the Multiple Sleep Latency Test, an objective measure of sleepiness.22
The Calgary SAQLI has 35 questions organized into four domains: daily functioning, social interactions, emotional functioning, and symptoms, with a fifth domain, treatment-related symptoms, to record the possible negative impacts of treatment. The SAQLI has a high degree of internal consistency, face validity as judged by content experts and patients, and construct validity as shown by its positive correlations with the Short Form-36 Health Survey questionnaire and the improvement in scores in patients successfully completing a 4-week trial of CPAP. It contains items shown to be important to patients with sleep apnea, and it is designed as a measure of outcome in sleep apnea clinical trials.23 Scoring of the SAQLI was based on the manual by Flemons and Reimer.24
Cognitive function tests, including trail-making, digit-symbol, digit-span, and Stroop color testing, were performed to provide objective evidence for improvement in daytime function on CPAP treatment, as reported by Engleman et al.7 8 9 10 The trail-making test estimated the minimum time required to connect a structured number sequence; the lower the score, the better the performance. The digit-symbol and digit-span tests involved the immediate memory and recall of number sequences, while the Stroop color test evaluated the correct matching of colors and their corresponding characters. For the Stroop color, digit-symbol, and digit-span tests, a higher score indicated superior performance.
With the exception of the ESS, which was repeated at 3 months, all other baseline measurements were repeated at 1 month and 3 months. During the CPAP clinic follow-up, our patients were asked to report subjectively the amount of time they used the CPAP device per day and any problem associated with the use of CPAP.
The objective CPAP compliance was measured at 1 month and 3 months, with the Aria CPAP data downloaded into a personal computer using the Respironics Encore software (Respironics). The time spent at effective pressure was recorded as the objective compliance.
Statistical Analysis
Data were analyzed on an intention-to-treat basis. For
comparison between basic and augmented education groups at each time
point, an unpaired t test was used for normally distributed
variables, and the Mann-Whitney test was used for nonnormally
distributed variables. The improvement of variables from baseline was
tested by paired t test.
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Results |
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TOPAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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Compliance
There was no significant difference between the two groups in
terms of objective CPAP usage and compliance rates. At 4 weeks, the
CPAP usage was 5.3 ± 0.2 h/night vs 5.5 ± 0.2 h/night
(p = 0.4), while at 12 weeks, the CPAP usage was 5.3 ± 0.3 h/night
vs 5.3 ± 0.2 h/night (p = 0.98) in the BS and AS groups,
respectively. The compliance rates were 71% at both 4 weeks and 12
weeks in the BS group, while those of the AS group were 79% and 74%,
respectively. At both 4 weeks and 12 weeks, patients in both groups
overestimated the actual amount of time they used CPAP, with the
self-reported compliance much higher than the objective compliance in
both groups (p < 0.001; Table 2
).
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Discussion |
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TOPAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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Several studies have been published examining ways to facilitate CPAP compliance. Fletcher and Luckett,14 in a prospective, randomized crossover study, examined the effect of weekly (thrice) and then monthly (twice) positive reinforcement via telephone support on hourly compliance of 10 new CPAP users for 3 months vs no reinforcement for 3 months. Their study suggested that positive reinforcement by telephone did not favorably alter compliance. However, as half of their patients had already received telephone support during the reinforced period, it was difficult to determine the effects of reinforcement, as there was likely a carrying-over effect of such support in the nonreinforced period. In a randomized controlled trial involving 33 subjects of two interventions to improve compliance, Chervin et al25 showed that telephone support or educational literature might improve self-reported CPAP usage, but their result fell short of statistical significance (p = 0.059). In a retrospective and nonrandomized study of 73 patients in an outpatient clinic, Likar et al26 showed that group education sessions could improve compliance with CPAP therapy. More recently, in a prospective study of 80 consecutive new patients with OSA, randomized to receive usual support or additional nursing input (including CPAP education at home and involving their partners, a 3-night trial of CPAP titration in a sleep center, followed by additional home visits), Hoy et al27 reported that there was greater improvement of objective CPAP compliance, OSA symptoms, mood, and reaction time in the intensively supported group at 6 months. However, such an intensive approach, which involves 2 extra nights of CPAP titration and additional nursing staff to provide home visits, is rather costly and may not be feasible or cost-effective in most sleep disorder centers with preexisting long queues for sleep studies.
Despite supplementing the education session with a 15-min videotape, a longer CPAP education session by nurses, telephone support in the first 3 months, and early follow-up, CPAP compliance was not significantly increased among our new CPAP users in the AS group. As there was no significant difference between the two groups in terms of CPAP usage, it was not surprising that, apart from a greater improvement of digit span of marginal statistical significance (p = 0.049) at 4 weeks in the AS group, there was no significant difference in improvement of other cognitive function outcome variables at 4 weeks, and subsequent reassessment of cognitive function and ESS at 12 weeks.
The AS group reported greater improvement of quality of life at 4 weeks and 12 weeks (p = 0.008 and p = 0.047, respectively), and this was likely related to the psychological support and attention given to the patients by our nurses via telephone daily for the first 2 days, weekly for the first 4 weeks, and monthly for the subsequent 2 months, together with the weekly review by physicians in the first 2 weeks immediately after commencement of CPAP therapy.
The lack of significant improvement in CPAP compliance in the AS group might be due to the fact that our BS program was highly adequate and the additional measures did not confer any extra benefit. Indeed, overall, 71% of our patients in the BS group used their CPAP for at least 4 h/d, and at least 70% of the nights per week at 4 weeks and 12 weeks. The compliance rate was slightly lower than the 79% reported by Pepin et al28 in a prospective, multicentre, European study, but much higher than that of 46% reported by Kribbs et al12 in an American population. Our BS program consisted of educational brochures on OSA and CPAP, practical CPAP education, and acclimatization sessions conducted by our nurses, plus early CPAP clinic review at 4 weeks; these are all essential elements ensuring good CPAP compliance. The mean CPAP usage in the BS group of this study was more than the 3.9 h/night reported by Hoy et al27 in their control group at 6 months. Apart from different patient populations, the major difference between their protocol and ours is the inclusion of educational brochures in our study. In addition, most of our patients had to purchase or rent the CPAP units themselves, and this factor may have increased the motivation of our patients. Our compliance results support the findings by Kribbs et al,12 that the degree of compliance established within the first month of treatment with CPAP reliably predicts compliance at 3 months. Moreover, self-reported compliance, which was overestimated by our patients as in other studies,12 13 29 should not be considered a reliable means to establish compliance.
There were several limitations in our study. Despite the randomization process, there were some differences in the baseline ESS score and trail B between the two groups. Hence, analysis was based on comparison of changes from baseline for the variables between the two groups. Apart from the CPAP usage measured by the Respironics Aria and Encore software and cognitive function tests, all other outcome variables such as ESS and SAQLI were subjective rather than objective measurements. There was also a technical failure with the Aria/Encore software, resulting in missing CPAP compliance data for two patients in the BS group and nine patients in the AS group at 12 weeks. Until there is breakthrough in the treatment of sleep-disordered breathing, CPAP remains a life-long therapy for most patients with OSA, but the results reported in this study were only up to 3 months of therapy. However, there is evidence from a large follow-up study that the average nightly CPAP use within the first 3 months is strongly predictive of long-term use.30 As an additional criticism of this study, automatic CPAP titration may not be regarded as standard practice by every sleep laboratory. However, the significant improvement of ESS at 12 weeks and SAQLI at 4 weeks and 12 weeks in both groups reassured us that the attended automatic CPAP titration had been effective. Automatic CPAP titration does not reduce the use19 or acceptance20 of CPAP compared with manual titration. The subsequent reduction in CPAP requirement in our patients has also been observed even with manual titration by Jokic et al31 within 2 weeks of starting CPAP treatment, and this was likely to be due to resolution of upper-airway edema.32
In summary, this randomized controlled study shows that augmentation of CPAP education and support does not improve CPAP usage at 1 month and 3 months following commencement of CPAP treatment, but leads to a greater improvement of quality of life during the reinforced period. Nevertheless good basic education and support are essential in ensuring good CPAP compliance, and this is reflected by the high level of CPAP compliance in our patient population.
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Acknowledgements |
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Footnotes |
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Supported by the Health Service Research Committee Grant ().
Received for publication August 20, 1999. Accepted for publication January 5, 2000.
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