Non-invasive ventilation for people with neuromuscular disorders in Australia and New Zealand: a qualitative study of clinician perspectives.

OBJECTIVES: To explore the experiences of Australian and New Zealand clinicians with respect to care pathways, their awareness and use of non-invasive ventilation guidelines, and their perspectives on delivering quality non-invasive ventilation services to people with neuromuscular disorders. DESIGN, SETTING, PARTICIPANTS: Qualitative study; semi-structured focus groups and individual interviews with Australian and New Zealand clinicians who provide non-invasive ventilation services to people with neuromuscular disorders, recruited from participants at a 2017 sleep medicine conference. Interviews were conducted during 1 October 2017 - 31 May 2018. MAIN OUTCOME MEASURES: Major themes identified by an iterative, semantic, and inductive analysis. RESULTS: A total of 28 participants attended the four focus group sessions and five individual interviews; fourteen each from New Zealand and Australia, seventeen women and eleven men, eighteen physicians and ten other clinicians. Two major themes were identified: decision making for current practice, and resource constraints. Participants noted variable use of clinical guidelines and limited training to meet the needs of people with neuromuscular disorders who require non-invasive ventilation. They described a lack of dedicated funding, unstructured care pathways, equipment supply levels that do not meet need, low staff-to-patient ratios and staff shortages, and the inability to deliver quality multidisciplinary care. The need for clinical guidelines and service specifications was highlighted as requisite for reducing variation in clinical care. CONCLUSIONS: Systemic factors influence the needs-based provision of non-invasive ventilation for people with neuromuscular disorders. Development of clinical guidelines for Australia and New Zealand, dedicated funding for respiratory services for people with neuromuscular disorders, and specialist clinician training are important for equitable and high quality non-invasive ventilation care.

Health System Factors Affecting the Experience of Non-Invasive Ventilation Provision of People with Neuromuscular Disorders in New Zealand.

Non-invasive ventilation (NIV) is a critical therapy for many patients with neuromuscular disorders (NMD), supporting those with respiratory failure to achieve adequate respiration and improve their quality of life. The aim of this study was to explore the experiences of access to, consent, uptake, maintenance and safe use of non-invasive ventilation by people with NMD. Semi-structured individual interviews were conducted with 11 people with NMD, each using NIV for more than 12 months. A critical realism ontological paradigm with contextualism epistemology guided the Reflexive Thematic Analysis. An Equity of Health Care Framework underpinned the analysis. Three themes were interpreted: Uptake and informed consent for NIV therapy; Practicalities of NIV; and Patient-clinician relationships. We identified issues at the system, organization and health professional levels. Conclusions: We recommend the development of national service specifications with clear standards and dedicated funding for patients with NMD and call on the New Zealand Ministry of Health to proactively investigate and monitor the variations in service delivery identified. The specific areas of concern for patients with NMD suggest the need for NMD-related NIV research and service provision responsive to the distinct needs of this population.

"Me and 'that' machine": the lived experiences of people with neuromuscular disorders using non-invasive ventilation.

PURPOSE: Neuromuscular disorders (NMD) encompasses a wide range of conditions, with respiratory weakness a common feature. Respiratory care can involve non-invasive ventilation (NIV) resulting in fewer hospital admissions, a lower mortality rate and improved quality of life. The aim of this study was to explore the 'lived experience' of NIV by people with NMD. METHODS: Interpretive Phenomenological Analysis (IPA) with semi-structured, face to face interviews with 11 people with NMD, using bi-level positive airway pressure for NIV for more than 12 months. RESULTS: Three themes were interpreted: (i) Alive, with a life; (ii) Me and 'that' machine; and (iii) Precariousness of this life. NIV enabled hope, independence and the opportunity to explore previously perceived unattainable life experiences. Yet, participants felt dependent on the machine. Furthermore, practical considerations and fear of NIV failure created a sense of precariousness to life and a reframing of personal identity. CONCLUSION: The findings highlight the broad ranging positive and negative effects that may occur for people with NMD when using this important therapy. Ongoing non-judgemental support and empathy are required from health professionals as the use of NIV challenged concepts such as 'living life well' for people with NMD. IMPLICATIONS FOR REHABILITATIONNeuromuscular disorders may result in respiratory weakness requiring non-invasive ventilation (NIV).When prescribed early, NIV can results in fewer hospital admissions, a lower mortality rate and improved quality of life.The relationship of people with NMD with their NIV machine is complex and impacts on and requires adjustment to their identity.NIV users acknowledged that NIV provided hope but simultaneously recognised the precariousness of NIV on their life.In order to better support people with NMD healthcare professionals need to better understand how the physical, psychological and social implications of NIV affect an individual's life.

Noninvasive ventilation in New Zealand: a national prevalence survey.

BACKGROUND: Home-based noninvasive ventilation (NIV) is an effective treatment for a range of conditions that cause respiratory failure which reduces hospitalisation and mortality and improves quality of life. AIMS: To collect NIV prevalence, disease burden and equity data needed for effective national NIV health service planning. METHODS: The authors collected demographics and the primary diagnosis of patients receiving publicly funded NIV in New Zealand in 2018 by surveying all providers. National and regional prevalence rates were calculated using adult population data (aged ≥20 years) for each District Health Board region compared with a 2011 study. A subanalysis of individual-level data was used to calculate age-standardised rates by diagnostic category. RESULTS: A total of 1197 adults were receiving NIV giving a national rate of 32.9 per 100 000; almost twice the 2011 rate (16.7 per 100 000). Significant regional variations in NIV provision (4.5-84.2 per 100 000) were observed. The most frequent indications were obesity hypoventilation syndrome (OHS) (562, 47%), obstructive pathologies (335, 28%) and neuromuscular disorders (175, 15%); all have significantly increased in prevalence since 2011. Maori and Pacific peoples were significantly overrepresented among NIV users (2.24 [95% confidence interval (CI), 1.72-2.93] and 7.03 [95% CI, 5.52-8.94], respectively). The prevalence of NIV-dependent use (>15 h/day) was 4%. CONCLUSIONS: Home-based NIV provision has doubled since the previous survey, reflecting increased burden from OHS and obstructive pathologies and a disproportionate disease burden among Maori and Pacific populations. The large regional variations are concerning and highlight the urgent requirement for national service specifications, education and equipment provision. Further research is needed to address access equity.

From diagnosis to long-term management: the experiences of older New Zealanders with obstructive sleep apnoea.

INTRODUCTION In New Zealand (NZ), access to public sleep services is limited to people deemed with the highest need. The prevalence of obstructive sleep apnoea (OSA) increases with age, but the symptoms and the treatment pathway is expected to differ for older compared to younger patients. This study explored the experience of older people regarding diagnosis and treatment services for OSA in order to inform considerations required in primary health and sleep services. METHODS Patients who were initiated on Continuous Positive Airway Pressure (CPAP) therapy at the age of 65 years or older were invited to one of three 1.5-h focus group discussions. In total, 16 patients attended; nine were accompanied by their spouse or partner. Discussions were semi-structured and explored experiences with the OSA pathway, from diagnosis through to long-term management. RESULTS Thematic analysis highlights the key symptoms of OSA. Patients' experiences with diagnostic and treatment services were generally positive. However, there was an overarching need for greater knowledge and follow up regarding OSA and CPAP therapy. Most patients were happy with CPAP treatment. Issues associated with long-term use, comfort and daily management were highlighted, and strategies used to overcome them discussed. DISCUSSION Focus groups reported similar experiences, positively endorsing the health value of OSA diagnosis and CPAP therapy. Mechanisms and resources are required at a primary healthcare level in order to raise awareness around sleep and aging, OSA and CPAP. This would aid earlier and more appropriate diagnosis and management of OSA and help overcome some of the gaps identified in this study.

Clinical Reproducibility of the Epworth Sleepiness Scale for Patients With Suspected Sleep Apnea.

STUDY OBJECTIVES: To determine the reproducibility of the Epworth Sleepiness Scale (ESS) score in a clinical population referred for diagnostic testing with suspected obstructive sleep apnea. METHODS: A retrospective audit of patients referred for a diagnostic sleep study with suspected sleep apnea was undertaken. Data collection was two 3-month time periods from January to March in 2012 and 2014. To evaluate reproducibility, the ESS score at primary care referral was compared to the ESS score at first specialist assessment/sleep assessment. The proportion of scores changing by more than 2, 3, 5, or 7 points was determined. Data were analyzed using Bland-Altman plots and paired t tests. RESULTS: A total of 154 patients (68% male) with a mean ± standard deviation age of 51 ± 13 years, body mass index 36 ± 10 kg/m2, and apnea-hypopnea index 43 ± 40 events/h were included. The average ESS score change was -0.2 with a standard deviation of 3.9 reflecting a wide scatter. A difference between the sequential ESS scores of 5 or more was seen in 21% of subjects. CONCLUSIONS: In a clinical obstructive sleep apnea referral population, the ESS score was variable when administered sequentially. Given this variability the ESS should not be used as the sole tool to prioritize patients for obstructive sleep apnea assessment. COMMENTARY: A commentary on this article appears in this issue on page 711.

Continuous positive airway pressure treatment for obstructive sleep apnoea: Maori, Pacific and New Zealand European experiences.

INTRODUCTION: Continuous positive airway pressure (CPAP) is an effective treatment of obstructive sleep apnoea (OSA), but can be limited by poor adherence. In New Zealand (NZ), ethnicity has been shown to be a predictor of CPAP adherence. This study aimed to explore Maori , Pacific and NZ European patients' experience of CPAP treatment. METHODS: Patients identifying as Maori , Pacific, or NZ European ethnicity referred for CPAP treatment for OSA attended separate, 1.5-hour group discussions facilitated by a health care worker of the same ethnic group, using an interview template. Thematic analysis was applied to the discussion transcripts independently by two investigators, following published guidelines. FINDINGS: Five Maori , five Pacific, and eight NZ Europeans participated (mean age 47, range 30-71 years, mean ± standard deviation CPAP adherence 6.32 ± 1.25 hours/night). Patients in all three groups reported that they had little knowledge of OSA or CPAP prior to treatment initiation. All groups identified barriers to treatment (both at the CPAP initiation phase and long term), reported feelings of being 'overwhelmed' with information during the initial CPAP education session, and discussed the importance of successful role models. Family and friends were generally reported as being supportive of CPAP therapy. CONCLUSION: The three groups all reported similar initial CPAP experiences, highlighting access barriers to publicly funded assessment and treatment pathways, and sleep health knowledge as key issues. Educational resources to improve access, enable self-management, and increase community awareness of OSA would help overcome some of the issues identified in this study.

Home mechanical ventilation in Australia and New Zealand.

This study aims to describe the pattern of home mechanical ventilation (HMV) usage in Australia and New Zealand. 34 centres providing HMV in the region were identified and asked to complete a questionnaire regarding centre demographics, patient diagnoses, HMV equipment and settings, staffing levels and methods employed to implement and follow-up therapy. 28 (82%) centres responded, providing data on 2,725 patients. The minimum prevalence of HMV usage was 9.9 patients per 100,000 population in Australia and 12.0 patients per 100,000 population in New Zealand. Variation existed across Australian states (range 4-13 patients per 100,000 population) correlating with population density (r=0.82; p<0.05). The commonest indications for treatment were obesity hypoventilation syndrome (OHS) (31%) and neuromuscular disease (NMD) (30%). OHS was more likely to be treated in New Zealand, in smaller, newer centres, whilst NMD was more likely to be treated in Australia, in larger, older centres. Chronic obstructive pulmonary disease was an uncommon indication (8.0%). No consensus on indications for commencing treatment was found. In conclusion, the prevalence of HMV usage varies across Australia and New Zealand according to centre location, size and experience. These findings can assist HMV service planning locally and highlight trends in usage that may be relevant in other countries.

The effect of continuous positive airway pressure usage on sleepiness in obstructive sleep apnoea: real effects or expectation of benefit?

RATIONALE: Placebo responses are complex psychobiological phenomena and often involve patient expectation of benefit. With continuous positive airway pressure (CPAP) treatment of obstructive sleep apnoea, greater hours of CPAP use are associated with reduced sleepiness. However, these open-label studies have not controlled for patient expectation of benefit derived from their knowledge of hours of device use. OBJECTIVES: To investigate the relative effectiveness of the use of real or placebo CPAP on daytime sleepiness. METHODS: Patient-level meta-analysis combining data on sleepiness measured by the Epworth Sleepiness Scale from three randomised placebo-controlled crossover trials. Mixed model analysis of variance was used to quantify the effects of real versus placebo device treatment, usage, their interaction and regression to the mean. MEASUREMENTS AND MAIN RESULTS: Duration of real and placebo CPAP use was correlated within patients (r=0.53, p<0.001). High use of real CPAP reduced sleepiness more than high use of placebo (difference 3.0 points; 95% CI 1.7 to 4.3, p<0.001) and more than low use of real CPAP (difference 3.3; 95% CI 1.9 to 4.7, p<0.0001). High use of placebo was superior to low use of placebo (difference 1.5; 95% CI 0.1 to 2.8, p=0.03). Twenty-nine per cent of the effect of high usage of CPAP (4.2 points; 95% CI 3.3 to 5.1) was explained by the expectation of benefit effect associated with high use of placebo (1.2 points ; 95% CI 0.2 to 2.3). CONCLUSIONS: A clinically significant proportion of the effectiveness of high CPAP use in reducing sleepiness is probably caused by patient expectation of benefit.

Nasal versus oronasal continuous positive airway pressure masks for obstructive sleep apnea: a pilot investigation of pressure requirement, residual disease, and leak.

PURPOSE: This single-blinded, randomized, controlled pilot study aimed to investigate whether there is a difference between nasal and oronasal masks in therapeutic continuous positive airway pressure (CPAP) requirement, residual disease, or leak when treating obstructive sleep apnea (OSA) and if differences were related to measures of upper airway size. METHODS: Patients with severe OSA currently using CPAP at ≥4 h/night with a nasal mask were examined (including Mallampati scale, incisal relationship, and mandibular protrusion) and then randomized to receive auto-positive airway pressure (PAP) or fixed CPAP at a manually titrated pressure for 1 week each at home, with immediate crossover. Within each week, a nasal mask and two oronasal masks were to be used for two or three nights each in random order. Data were downloaded from the device. RESULTS: Twelve patients completed the trial (mean ± SD AHI 59.8 ± 28.6 events/h; CPAP 11.1 ± 3.2 cmH(2)O; BMI 37.7 ± 5.0 kg/m(2)). During auto-PAP, the median 95th percentile pressure delivered with all masks was within 0.5 cmH(2)O (p > 0.05). During CPAP, median residual AHI was 0.61 (IQR = 1.18) for the nasal mask, 1.70 (IQR = 4.04) for oronasal mask 1, and 2.48 (IQR = 3.74) for oronasal mask 2 (p = 0.03). The 95th percentile leak was lowest with the nasal mask during both CPAP and auto-PAP (both p < 0.01). Differences in pressure or residual disease were not related to measures of upper airway shape or body habitus. CONCLUSIONS: In obese OSA patients changing from a nasal to oronasal mask increased leak and residual AHI but did not affect the therapeutic pressure requirement. The findings of the current study highlight mask leak as the major difficulty in the use of oronasal masks.

Ethnic disparities in CPAP adherence in New Zealand: effects of socioeconomic status, health literacy and self-efficacy.

STUDY OBJECTIVES: We aimed to investigate the influence of ethnicity on adherence with continuous positive airway pressure (CPAP) in a sample of New Zealand patients. DESIGN: Observational study over one month. SETTING: A university-based sleep laboratory. PATIENTS: 126 consecutively consenting CPAP-naïve patients (19.8% Maori, mean±SD apnea-hypopnea index 57.9 ± 38.9 events/h, CPAP 11.1 ± 3.1 cm H2O). INTERVENTIONS: Patients underwent a 4-week supervised home trial of CPAP following pressure titration. MEASUREMENTS AND RESULTS: Self-identified ethnicity (Maori/non-Maori), Epworth Sleepiness Scale, Self-Efficacy Measure for Sleep Apnea, Rapid Estimate of Adult Literacy in Medicine, New Zealand Deprivation Index (calculated from residential address), New Zealand Individual Deprivation Index (validated 8-item questionnaire), educational history, income, and employment assessed at baseline were compared to objective CPAP adherence after one month. Maori demonstrated significantly lower usage than non-Maori (median 5.11, interquartile range 2.24 h/night compared with median 5.71, interquartile range 2.61 h/night, P = 0.05). There were no significant relationships between adherence and subjective sleepiness, health literacy, or self-efficacy. In a multivariate logistic regression model incorporating 5 variables (ethnicity, eligibility for government-subsidized healthcare, individual deprivation scores, income, and education), non-completion of tertiary education, and high individual socioeconomic deprivation remained significant independent predictors of average CPAP adherence not reaching ≥ 4 h (odds ratio 0.25, 95% CI 0.08-0.83, P = 0.02; odds ratio 0.10, 95% CI 0.02-0.86, P = 0.04, respectively). The overall model explained approximately 23% of the variance in adherence. CONCLUSIONS: The disparity in CPAP adherence demonstrated between Maori and non-Maori can be explained in part by lower education levels and socioeconomic status.

Pulse wave analysis in a pilot randomised controlled trial of auto-adjusting and continuous positive airway pressure for obstructive sleep apnoea.

PURPOSE: Non-invasive measurements of arterial stiffness including the augmentation index (AIx) and central blood pressure (BP) have been used to assess the cardiovascular health of patients with obstructive sleep apnoea (OSA), a well-established independent risk factor of cardiovascular disease. Continuous positive airway pressure (CPAP) can significantly reduce the AIx, but no studies have analysed the effect of auto-adjusting PAP (APAP) or studied morbidly obese patients with severe OSA at higher risk of cardiovascular disease. In this randomised, single-blinded crossover pilot trial, we aimed to compare the efficacy of CPAP with APAP (ResMed S8 Autoset II) in improving peripheral BP, central BP and the AIx, using SphygmoCor technology. METHODS: Twelve severe OSA patients (mean±SD; apnoea-hypopnoea index, 75.8 ± 32.7; BMI, 49.9 ± 5.2 kg/m(2)) were consecutively recruited and received CPAP (mean pressure, 16.4 cm H(2)O) or APAP in random order for four nights at home, separated by a four-night washout. Cardiovascular measurements were taken at baseline, post-washout and following each treatment arm. RESULTS: The polysomnographically recorded residual apnoea-hypopnoea index and compliance to treatment were not significantly different between arms (p > 0.05). There were no significant differences in peripheral or central BP between arms (p > 0.05). The AIx was lower with CPAP than APAP (by 5.8%), with a large effect size not reaching statistical significance (r = 0.61, p = 0.14). CONCLUSION: The large effect size evident when comparing the AIx following CPAP and APAP indicates the need to perform an adequately powered trial in order to determine if APAP improves arterial stiffness to the same extent as CPAP.

Randomised controlled trial of auto-adjusting positive airway pressure in morbidly obese patients requiring high therapeutic pressure delivery.

Auto-adjusting positive airway pressure (APAP) devices are being increasingly used to treat obstructive sleep apnoea (OSA). Anecdotal encounters of obese patients requiring high therapeutic pressure whose OSA was inadequately controlled by APAP led to this study aiming to compare the effectiveness of continuous positive airway pressure (CPAP) and APAP (S8 Autoset II(®) , ResMed, NSW, Australia) in a randomised, single-blinded crossover trial. Twelve morbidly obese patients with severe OSA [mean±SD apnoea-hypopnoea index (AHI) 75.8±32.7, body mass index 49.9±5.2 kg m(-2) , mean pressure 16.4 cmH(2)O] were consecutively recruited, and received CPAP or APAP in random order for six nights at home, separated by a four-night washout. Polysomnographic (PSG) indices of OSA were recorded at baseline and following each treatment arm. Both therapies substantially reduced the AHI (APAP 9.8±9.5 and CPAP 7.3±6.6 events h(-1) ; P=0.35), but residual PSG measures of disease (AHI >5) were common. APAP delivered a significantly lower 95th percentile pressure averaged over the home-use arm than CPAP (14.2±2.7 and 16.1±1.8 cmH(2)O, respectively, P=0.02). The machine-scored AHI significantly overestimated the level of residual disease compared with the laboratory-scored AHI (using Chicago criteria); however, when the machine-scored AHI was ≤5 and ≤10 this was always confirmed by the PSG data. In morbidly obese OSA patients without significant co-morbid disease requiring high therapeutic pressure, our data provide support for the use of either APAP or manually titrated CPAP. We recommend objective assessment by sleep study if the S8 Autoset II indicates a high level of residual disease.

Home set-up polysomnography in the assessment of suspected obstructive sleep apnea.

Home set-up polysomnography (PSG) has advantages over other portable monitoring devices, but remains unendorsed by professional bodies despite excellent utility in the Sleep Heart Health Study (SHHS). The study aims to determine technical reliability and diagnostic accuracy of unattended, home set-up versus attended laboratory-based PSG in patients with suspected obstructive sleep apnea (OSA). Thirty patients with suspected OSA without significant co-morbidity were recruited. After initial lab-PSG (Compumedics S series), patients underwent home set-up PSG (Compumedics Siesta) and lab-based PSG in random order. Studies were compared for study success, signal loss and likelihood ratio for OSA diagnosis [apnea-hypopnea index (AHI) >10]. Thirty subjects (mean age 49±13.8 years, body mass index 31±6.1 kg m(-2) ) completed investigations. SHHS technical acceptability criteria were met by all lab-based PSGs and 90% of home-based PSGs (93% clinically acceptable). Signal loss was higher at home (P=0.008). Sleep efficiency was similar between sites, but more preferred home-based PSG (50%). ancova revealed AHI was significantly different if initial AHI >26 per h (P=0.006), with an average underestimate of 5.1 per h at home. In technically acceptable studies the likelihood ratios to 'rule in' and 'rule out' OSA were 8.1 and 0.1, respectively. Unattended, home set-up PSG is technically reliable and achieves excellent diagnostic utility. Signal loss was higher at home but mitigated by multi-channel redundancy. Success rate was similar to SHHS and superior to laboratory set-up home studies. Home set-up PSG is a valid alternative to laboratory-based PSG for suspected OSA.

Randomized controlled trial comparing flexible and continuous positive airway pressure delivery: effects on compliance, objective and subjective sleepiness and vigilance.

STUDY OBJECTIVES: Positive airway pressure (PAP) treatment for obstructive sleep apnea (OSA) can be limited by suboptimal compliance. C-Flex technology (Philips Respironics, PA, USA) reduces pressure during expiration, aiming to improve comfort and therefore compliance. This may be of particular relevance to patients requiring high pressures. Many studies thus far have suffered from design limitations and small sample sizes. This study aimed to compare compliance with C-Flex and CPAP, as well as analyzing objective and subjective sleepiness and vigilance. DESIGN: Three-month, double-blinded, parallel-arm randomized controlled trial. SETTING: A university-based sleep laboratory. PATIENTS: 76 consecutive patients with severe OSA (mean +/- SD AHI 60.2 +/- 32.9 events/hour, ESS 13.6 +/- 4.5/24, BMI 35.6 +/- 7.8 kg/m2), without significant cardiac, respiratory, psychiatric, or sleep comorbidities. INTERVENTIONS: Patients were randomized to C-Flex (dip level 2) or CPAP. MEASUREMENTS AND RESULTS: Patients underwent titration with C-Flex/CPAP (mean pressure 11.6 cm H2O). Modified maintenance of wakefulness tests (mod-MWT), psychomotor vigilance tasks (PVT) and questionnaires were administered at baseline and after one and 3 months. Median compliance was 5.51 and 5.89 h/night in the C-Flex and CPAP groups respectively (P = 0.82). There were no significant differences between groups in terms of PVT reaction time, subjective sleepiness, sleep quality, health-related quality of life, or treatment comfort. There was no significant difference between the groups regarding the change in mod-MWT sleep latency values. CONCLUSIONS: In patients with severe OSA both CPAP and C-Flex resulted in substantial improvements in sleepiness, vigilance, and quality of life. The use of C-Flex did not result in greater compliance, and neither treatment appeared superior.

Obstructive sleep apnea in New Zealand adults: prevalence and risk factors among Maori and non-Maori.

STUDY OBJECTIVES: Examine the distribution of symptoms and risk factors, and estimate the prevalence of obstructive sleep apnea (OSA) among Maori and non-Maori New Zealanders. DESIGN: Mail-out survey to a stratified random sample from the electoral roll of 10,000 people aged 30-59 y, and overnight MESAM IV monitoring during sleep of a similarly aged stratified random sample of 364 people from the Wellington electoral roll. SETTING: Nationwide survey of OSA symptoms (71% response rate) and regional home-based measurement of respiratory disturbance index (RDI, 4% oxygen desaturations/h of sleep, plus bursts of snoring or > or = 10/min increase in heart rate). PARTICIPANTS: Sample designs aimed for equal numbers of Maori and non-Maori participants, men and women, and participants in each decade of age. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Maori were more likely than non-Maori to report OSAS risk factors and symptoms. After controlling for sex and age, Maori were 4.3 times more likely to have RDI > or = 15 (95% CI = 1.3-13.9). Ethnicity was not an independent risk factor after controlling for body mass index (BMI) and neck circumference. The prevalence of OSAS (RDI > or = 5 and ESS > 10) was conservatively estimated to be 4.4% for Maori men, 4.1% for non-Maori men, 2.0% for Maori women, and 0.7% for non-Maori women. CONCLUSIONS: The national survey and the regional monitoring study indicate a higher prevalence of OSA among Maori and among men. The higher prevalence among Maori appears to be attributable to recognized risk factors, notably body habitus. In addition to increased prevention and treatment services, strategies are needed to reduce ethnic disparities in OSAS prevalence.

Randomised trial of compliance with flexible (C-Flex) and standard continuous positive airway pressure for severe obstructive sleep apnea.

INTRODUCTION: Obstructive sleep apnea (OSA) is often treated with continuous positive airway pressure (CPAP) but the effectiveness of treatment is probably limited by poor compliance. CPAP manufacturers are thus attempting to devise more comfortable PAP devices in an effort to improve compliance. An example of such a novel device is Flexible expiratory-modulated PAP (C-Flex mode Respironics REMstar Pro, Murraysville, PA, USA). MATERIALS AND METHODS: We aimed to compare compliance between C-Flex and standard CPAP in patients with severe OSA in a randomised controlled trial. Nineteen patients with severe OSA (mean +/- SD Apnea Hypopnea Index = 78 +/- 33/h, Epworth 14 +/- 4, PAP 8-17 cm H2O, BMI = 39 +/- 10 kg/m2) and aged 20-63 years were randomly assigned to 4 weeks of either C-Flex (setting II, n = 9) or CPAP (n = 10). RESULTS: Patients treated with C-Flex exhibited a trend toward higher compliance with their PAP devices compared to patients treated with standard CPAP (4.7 +/- 2.9 vs. 3.0 +/- 2.1 h/night, p = 0.15, effect size = 0.68). Paradoxically, improvements in subjective sleepiness (Epworth Sleepiness Scale) were greater in those who received CPAP than C-Flex (8.1 + 4.9 vs. 2.1 + 4.0 points, p = 0.014, effect size = 1.46). Improvements in objective wakefulness (Modified Maintenance of Wakefulness Test) and simple reaction times (Psychomotor Vigilance Task) were not significantly different between treatments. This randomised trial provides some evidence that C-Flex might increase initial treatment compliance, compared to CPAP, in patients with severe OSA. However, this trend toward greater compliance was not associated with better short-term treatment outcomes for patients. These findings need to be confirmed in a larger, longer-term trial.