Sleep-disordered breathing and continuous positive airway pressure compliance in a group of commercial bus drivers in Hong Kong

Research gaps and needs for preventing worker fatigue in the transportation and utilities industries

BACKGROUND

The transportation and utilities industries include establishments engaged in the movement of passengers and freight, or the provision of public power, water, and other services. Along with the warehousing industry, they make up the US National Occupational Research Agenda's Transportation, Warehousing and Utilities (TWU) industry sector. In 2018 the sector composed 5% of the US workforce, with approximately 8 million workers. TWU workers experienced 19% of all fatalities among U.S. workers in 2018 and 7% of total occupational injuries and illnesses.

METHODS

Around-the-clock operations, heavy workloads, long and irregular shifts, complicated schedules, and time pressures characterize work across the US TWU sector. However, there are considerable differences in worker priorities and concerns between TWU industries. Major areas of concern within the sector include disparities in work schedules; required training for employee fatigue awareness and prevention; physical and mental job demands; and safety culture.

RESULTS

Strategies for fatigue mitigation are critical to reduce the prevalence of injuries, safety-critical events, and crashes in TWU workers. Further research on the incidence and characterization of fatigue among TWU workers will guide the development of effective mitigation strategies. The influence of work scheduling on missed sleep opportunities and disrupted circadian rhythms should be determined. Evaluation of fatigue mitigation strategies can lead to the adoption of the most effective ones for each TWU industry.

CONCLUSION

Implementation of effective strategies is critical for the health, safety, wellbeing, and productivity of workers in the TWU sector.

Effect of Weight Loss and CPAP on OSA and Metabolic Profile Stratified by Craniofacial Phenotype: A Randomized Clinical Trial

RATIONALE

Craniofacial structure is thought to modulate the effect of weight loss on OSA, but whether this affects metabolic profile after weight loss compared with continuous positive airway pressure(CPAP) is unknown among obese Chinese patients with obstructive sleep apnea(OSA).

OBJECTIVES

To compare the change in metabolic profile between lifestyle modification program(LMP), stratified by craniofacial phenotype, and CPAP therapy for 6 months.

METHODS

We randomly assigned 194 patients with BMI≥25kg/m2 and moderate-to-severe OSA to receive LMP or CPAP therapy for 6 months in a 2:1 ratio. Assessments included computed tomography for assessing maxillomandibular volume(MMV), high sensitivity C-reactive protein(hsCRP) and insulin sensitivity. Measurements and Main Results(mean±SD or median[interquartile range]): Among 128 and 66 subjects in LMP group and CPAP group, respectively, hsCRP reduced more in LMP group than the CPAP group (-0.7[-1.4 to -0.0]mg/L vs -0.3[-0.9 to 0.4]mg/L, p=0.012). More patients in LMP group achieved low hsCRP(<1mg/L) than the CPAP group(21.1% vs 9.1%, p=0.04). Insulin sensitivity improved only in LMP group with 3.1(95%CI 1.5-6.6) times more patients with normal glucose regulation after intervention. LMP group was stratified into LMP-small MMV(n=64) and LMP-large MMV(n=64) groups according to the median MMV value of 233.2cm3. There was no significant difference in hsCRP(-0.7[-1.3 to 0.1] vs -0.7[-1.5 to -0.2], p=0.884) and insulin sensitivity(0.5[-0.2 to 1.9] vs 0.6[0.1 to 2.0], p=0.4860) between LMP-small and LMP-large MMV groups.

CONCLUSION

Weight reduction improved subclinical inflammation and insulin sensitivity more than CPAP among obese Chinese patients with moderate to severe OSA, and this effect was not influenced by craniofacial structure. Clinical trial registration available at www.clinicaltrials.gov, ID: NCT03287973.

Continuous Positive Airway Pressure Does Not Improve Nonalcoholic Fatty Liver Disease in Patients with Obstructive Sleep Apnea. A Randomized Clinical Trial

Rationale: Obstructive sleep apnea (OSA) is associated with development of nonalcoholic fatty liver disease (NAFLD). The effects of continuous positive airway pressure (CPAP) on NAFLD in patients with concomitant OSA are unknown.Objectives: To investigate the effects of autoadjusting CPAP versus subtherapeutic CPAP treatment over 6 months on NAFLD activities.Methods: Patients with NAFLD and OSA, as defined by respiratory event index ≥5/h diagnosed by a validated level 3 Embletta device, were randomized into group A) autoadjusting CPAP (4-20 cm H₂O) or group B) subtherapeutic CPAP (pressure fixed at 4 cm H₂O). The primary endpoint was the difference in changes in intrahepatic triglyceride as measured by proton magnetic resonance spectroscopy after 6 months of therapy. Key secondary endpoints included changes in controlled attenuation parameter (CAP) and liver stiffness measurement measured with transient elastography, and serum cytokeratin-18 fragment.Measurements and Main Results: A total of 120 patients were randomized equally into two groups. There were significant correlations between CAP and respiratory event index (r = 0.203, P = 0.026), percentage of total recording time with Sa_O2 < 90% (r = 0.265, P = 0.003), and oxygen desaturation index (r = 0.214, P = 0.019). After 6 months of treatment, there were no significant differences of changes in primary and secondary endpoints between the two treatment groups. Regression analysis showed that weight change over 6 months correlated with changes in both intrahepatic triglyceride and CAP (P < 0.001).Conclusions: Despite significant correlations between hepatic steatosis and markers of severity of OSA, CPAP alone did not improve hepatic steatosis and fibrosis. However, the additional role of weight reduction through lifestyle modification deserves further investigation.

European Respiratory Society statement on sleep apnoea, sleepiness and driving risk

Obstructive sleep apnoea (OSA) is highly prevalent and is a recognised risk factor for motor vehicle accidents (MVA). Effective treatment with continuous positive airway pressure has been associated with a normalisation of this increased accident risk. Thus, many jurisdictions have introduced regulations restricting the ability of OSA patients from driving until effectively treated. However, uncertainty prevails regarding the relative importance of OSA severity determined by the apnoea–hypopnoea frequency per hour and the degree of sleepiness in determining accident risk. Furthermore, the identification of subjects at risk of OSA and/or accident risk remains elusive. The introduction of official European regulations regarding fitness to drive prompted the European Respiratory Society to establish a task force to address the topic of sleep apnoea, sleepiness and driving with a view to providing an overview to clinicians involved in treating patients with the disorder. The present report evaluates the epidemiology of MVA in patients with OSA; the mechanisms involved in this association; the role of screening questionnaires, driving simulators and other techniques to evaluate sleepiness and/or impaired vigilance; the impact of treatment on MVA risk in affected drivers; and highlights the evidence gaps regarding the identification of OSA patients at risk of MVA.

Factors associated with obesity in urban collective transportation workers of the Metropolitan Region of Belo Horizonte, Minas Gerais, Brazil

OBJECTIVE

To analyze the demographic, behavioral and occupational factors associated with obesity among urban collective transportation workers of the Metropolitan Region of Belo Horizonte, Minas Gerais State, Brazil.

METHOD

This is a cross-sectional study conducted with 1,448 drivers and collectors in the Metropolitan Region of Belo Horizonte. Anthropometric, demographic, behavioral data, as well as participants' link to the company and bus conditions were gathered in 2012 through a questionnaire applied by an interviewer. To calculate obesity, the body mass index cut off point was ≥ 30 kg/m2. Prevalence ratios (PR) and respective 95% confidence intervals (95%CI) were adjusted by Poisson's multivariate regression.

RESULTS

The prevalence of obesity among urban collective transportation workers was 16.1%. Female sex (PR = 1.84; 95%CI 1.37 - 2.49), aging 30 to 39 years old (PR = 1.66; 95%CI 1.17 - 2.37) and 40 to 49 years old (PR = 1.59; 95%CI 1.04 - 2.42), being in the same job role from 5.01 to 10 years (PR = 1.52; 95%CI 1.04 - 2,42) and from 20.01 to 47 years (PR = 1.90; 95%CI 1.21 - 3.00), and physical inactivity (PR = 1.32; 95%CI 1.01 - 1.73) remained independently associated with obesity after multivariate adjustment data.

CONCLUSION

These findings highlight the need to consider actions that encourage employees to participate in healthy activities when discussing health promotion for public transport workers, as well as actions to improve the organization and management of work, so it becomes a health and well-being feature for this population.

Usefulness of overnight pulse oximeter as the sleep assessment tool to assess the 6-year risk of road traffic collision: evidence from the Taiwan Bus Driver Cohort Study

Background

In order to support health service organizations in arranging a system for prevention of road traffic collisions (RTC), it is important to study the usefulness of sleep assessment tools. A cohort study was used to evaluate the effectiveness of subjective and objective sleep assessment tools to assess for the 6-year risk of both first RTC event only and recurrent RTC events.

Methods

The Taiwan Bus Driver Cohort Study (TBDCS) recruited 1650 professional drivers from a large bus company in Taiwan in 2005. The subjects were interviewed in person, completed the sleep assessment questionnaires and had an overnight pulse oximeter survey. Moreover, this cohort of drivers was linked to the National Traffic Accident Database (NTAD) and researchers found 139 new RTC events from 2005 to 2010. Primary outcomes were traffic collisions from NTAD, nocturnal oxygen desaturation index (ODI) from pulse oximeter, Pittsburg sleeping quality score, Epworth daytime sleepiness score, Snore Outcomes Survey score and working patterns from questionnaires. A Cox proportional hazards model and an extended Cox regression model for repeated events were performed to estimate the hazard ratio for RTC.

Results

The RTC drivers had increased ODI4 levels (5.77 ± 4.72 vs 4.99 ± 6.68 events/h; P  = 0.008) and ODI3 levels (8.68 ± 6.79 vs 7.42 ± 7.94 events/h; P  = 0.007) in comparison with non-RTC drivers. These results were consistent regardless of whether ODI was evaluated as a continuous or a categorical variable. ODI4 and ODI3 levels increased the 6-year RTC risks among professional drivers even after adjusting for age, education, history of cardiovascular disease, caffeine intake, sleeping pills used, bus driving experience and shift modes. Moreover, there was an increased trend for ODI between the stratification of the number of RTCs in comparison with the non-RTC group. In the extended Cox regression models for repeated RTC events with the Anderson and Gill intensity model and Prentice-Williams-Petersen model, measurement of ODI increased hazards of the subsequent RTC events.

Conclusion

This study showed that an increase in the 6-year risk of RTC was associated with objective measurement of ODI for a sign of sleep-disordered breathing (SDB), but was not associated with self-reported sleeping quality or daytime sleepiness. Therefore, the overnight pulse oximeter is an effective sleep assessment tool for assessing the risk of RTC. Further research should be conducted regarding measures to prevent against SDB among professional drivers.

[Study about the prevalence of the obstructive sleep apnoea syndrome in Vietnam]

INTRODUCTION

Epidemiological studies on obstructive sleep apnoea syndrome (OSAS) in Asia, South East Asia in particular, are few. The EPSASIE study aimed to determine the prevalence of OSAS in an adult Vietnamese population and to describe its characteristics.

METHODS

This is a prospective, observational, multicenter study. Nocturnal ventilatory polygraphy (PV) or polysomnography (PSG) were performed in patients having symptoms evocative of the SAS syndrome and an index of respiratory events (IER)>10/h or>25 in one hour, measured by RU Sleeping.

RESULTS

A total of 667/750 validated questionnaires were received. The mean age of the study population was 44±12 years with a mean body mass index of 21.6±5.2kg/m². PV or PSG were performed on 93 subjects after positive screening by RU Sleeping. OSAS with an apnoea-hypopnoea index (AHI)>5 was found in 57 subjects (8.5%) and in 35 subjects with AHI>15 (5.2% of cases).

CONCLUSION

The prevalence of OSAS is quite high in the Vietnamese population and comparable with current literature data.

An Adaptive Treatment to Improve Positive Airway Pressure (PAP) Adherence in Patients With Obstructive Sleep Apnea: A Proof of Concept Trial

Despite the benefits of positive airway pressure (PAP) treatment, rates of adherence to treatment are suboptimal. This proof-of-concept study assessed the feasibility, acceptability, and clinical significance of an adaptive treatment strategy to improve adherence to PAP. All participants first completed a brief educational intervention. Those who did not show at least a 25% increase in PAP use were randomized to receive a second, more intensive intervention, either motivational enhancement treatment or self-management treatment. Results suggested adequate feasibility and acceptability. In addition, participants demonstrated significant increases in objective PAP use, improvements in sleep quality, and decreases in daytime sleepiness. This study represents a first step in the development and validation of an adaptive treatment strategy to improve PAP adherence.

Acceptance and Adherence to Continuous Positive Airway Pressure Therapy in patients with Obstructive Sleep Apnea (OSA) in a Southeast Asian privately funded healthcare system

BACKGROUND

There is limited data on long term Continuous Positive Airway Pressure (CPAP) adherence in Southeast Asian countries. This is a prospective study on CPAP adherence among Obstructive sleep apnea (OSA) patients in a Southeast Asian privately funded healthcare system.

METHODS

Patients with moderate-severe OSA who had been initiated on CPAP at least one year previously were contacted for a scripted telephone interview to assess compliance and factors associated with CPAP adherence.

RESULTS

Of 135 consecutive patients diagnosed to have moderate to severe OSA, 78 (57.8%) were initiated on CPAP treatment while 57 (42.2%) rejected CPAP upfront. 41 (52.6%) who initiated CPAP remained adherent at one year. OSA severity (AHI, ODI) and symptomatic improvement after CPAP were associated with better adherence. Presence of machine related side effects was associated with lower adherence. Inconvenience, cost and poor disease perception were reported as major barriers to uptake of CPAP therapy.

CONCLUSIONS

In this Southeast Asian privately funded healthcare system, almost half of all patients with significant OSA rejected CPAP treatment upfront, but adherence among those who started CPAP is comparable to other reports. Challenges with CPAP acceptance as well as CPAP adherence need to be addressed to improve outcomes.

Utility of overnight pulse oximeter as a screening tool for sleep apnea to assess the 8-year risk of cardiovascular disease: Data from a large-scale bus driver cohort study

BACKGROUND

Professional drivers' work under conditions predisposes them for development of sleep-disordered breathing (SDB) and cardiovascular disease (CVD). However, the effect of SDB on CVD risk among professional drivers has never been investigated. A cohort study was used to evaluate the effectiveness of overnight pulse oximeter as a sleep apnea screening tool to assess the 8-year risk of CVD events.

METHODS

The Taiwan Bus Driver Cohort Study (TBDCS) recruited 1014 professional drivers in Taiwan since 2005. The subjects completed questionnaire interview and overnight pulse oximeter survey. This cohort was linked to the National Health Insurance Research Dataset (NHIRD). Researchers found 192 CVD cases from 2005 to 2012. Cox proportional hazards model was performed to estimate the hazard ratio for CVD. The statistical analysis was performed using SAS software in 2015.

RESULTS

ODI4 and ODI3 levels increased the 8-year CVD risk, even adjusting for CVD risk factors (HR: 1.36, 95% CI: 1.05 to 1.78; p=0.022, and HR: 1.40, 95% CI: 1.03 to 1.90; p=0.033). ODI4 and ODI3 thresholds of 6.5 and 10events/h revealed differences of CVD risks (HR: 1.72, 95% CI: 1.00 to 2.95; p=0.048, and HR: 1.76, 95% CI: 1.03 to 3.03; p=0.041). Moreover, the ODI levels had an increased risk for hypertensive disease (not including essential hypertension).

CONCLUSIONS

This study concludes that ODI for a sign of SDB is an independent predictor of elevated risk of CVD. Further research should be conducted regarding measures to prevent against SDB in order to reduce CVD risk in professional drivers.

Uncovering the sleep disorders among young doctors

PURPOSE

Sleepiness and tiredness are common complaints among young doctors. Sleep deprivation is believed to be the main culprit. However, we believe that there may be other sleep disorders which may contribute to these symptoms such as occult obstructive sleep apnea (OSA).

METHODS

A prospective cross-sectional study was performed among young doctors less than 40 years old, working at King Chulalongkorn Memorial Hospital, Bangkok, Thailand, and Hospital Kuala Lumpur, Kuala Lumpur, Malaysia, using questionnaires and home sleep apnea testing (Apnealink™Plus). The primary objective of this study was to evaluate the prevalence of OSA (apnea-hypopnea index (AHI) ≥5). The secondary objectives were to evaluate the prevalence of obstructive sleep apnea syndrome (OSAS) defined by AHI ≥5 + excessive daytime sleepiness (EDS), sleep deprivation (the difference of weekend (non-workdays) and weekday (workdays) wake-up time of at least 2 h), EDS (Epworth Sleepiness Scale score ≥10), tiredness, and perception of inadequate sleep as well as to identify their predictors.

RESULTS

Total of 52 subjects completed the study. Mean age and mean body mass index (BMI) were 31.3 ± 4 and 23.3 ± 3.6, respectively. The prevalence of OSA and OSAS were 40.4 and 5.8 %, respectively. One third of OSA subjects were at least moderate OSA. Prevalence of sleep deprivation, EDS, tiredness, and perception of inadequate sleep were 44.2, 15.4, 65.4, and 61.5 %, respectively. History of snoring, being male, and perception of inadequate sleep were significant predictors for OSA with the odds ratio of 34.5 (p = 0.016, 95 % CI = 1.92-619.15), 18.8 (p = 0.001, 95 % CI = 3.10-113.41), and 7.4 (p = 0.037, 95 % CI = 1.13-48.30), respectively. Only observed apnea was a significant predictor for OSAS with odds ratio of 30.7 (p = 0.012, 95 % CI = 2.12-442.6). Number of naps per week was a significant predictor for EDS with the odds ratio of 1.78 (p = 0.007, 95 % CI = 1.17-2.71). OSA and total number of call days per month were significant predictors for tiredness with the odds ratio of 4.8 (p = 0.036, 95 % CI = 1.11-20.72) and 1.3 (p = 0.050, 95 % CI = 1.0004-1.61), respectively. OSA was the only significant predictor for perception of inadequate sleep with the odd ratios of 4.5 (p = 0.022, 95 % CI = 1.24-16.59).

CONCLUSIONS

Our results demonstrated relatively high prevalence of OSA and OSAS among young doctors. Snoring, being male, and perception of inadequate sleep were significant predictors for OSA. Observed apnea was a significant predictor for OSAS. OSA was a significant predictor for tiredness and perception of inadequate sleep.

Factors associated with self-reported driver sleepiness and incidents in city bus drivers

Driver fatigue has received increased attention during recent years and is now considered to be a major contributor to approximately 15-30% of all crashes. However, little is known about fatigue in city bus drivers. It is hypothesized that city bus drivers suffer from sleepiness, which is due to a combination of working conditions, lack of health and reduced sleep quantity and quality. The overall aim with the current study is to investigate if severe driver sleepiness, as indicated by subjective reports of having to fight sleep while driving, is a problem for city based bus drivers in Sweden and if so, to identify the determinants related to working conditions, health and sleep which contribute towards this. The results indicate that driver sleepiness is a problem for city bus drivers, with 19% having to fight to stay awake while driving the bus 2-3 times each week or more and nearly half experiencing this at least 2-4 times per month. In conclusion, severe sleepiness, as indicated by having to fight sleep during driving, was common among the city bus drivers. Severe sleepiness correlated with fatigue related safety risks, such as near crashes.

Commercial Motor Vehicle Driver Positive Airway Pressure Therapy Adherence in a Sleep Center

STUDY OBJECTIVES

To assess positive airway pressure (PAP) therapy adherence in commercial motor vehicle (CMV) drivers presenting to a sleep center.

METHODS

A retrospective chart review of 120 drivers evaluated for obstructive sleep apnea OSA and 53 initiated on PAP therapy in a single sleep center over a one-year period (2012); PAP therapy data were collected up to 1 year.

RESULTS

Early PAP usage best predicted adherence up to 1 year (p < 0.0001) compared to patient factors, OSA disease characteristics, and treatment elements analyzed. The proportion of participants adherent to therapy was 68.0% at 1 week, decreasing to 39.6% at 1 year, with 31.1% lost to follow-up by 1 year. In the group categorized based on adherence at week 1, 80.6% were adherent at 1 month, decreasing to 52.8% at 1 year. For the group non-adherent at 1 week, 29.4% were adherent at 1 month, decreasing to 11.7% at 1 year. Participants were predominantly male (75.8%), middle-aged (median 50.5 years), and African American (71.7%). Of those referred to the sleep center, 86.7% had OSA (median apnea-hypopnea index [AHI] or respiratory event index [REI] 20.1), with 51.0% of the OSA group having an AHI or REI > 20 and initiating PAP therapy.

CONCLUSIONS

Early PAP utilization patterns predicted one year adherence for our CMV driver population within a sleep clinic setting. OSA testing of these CMV drivers after occupational health referral identifies high proportions of undiagnosed OSA, with approximately half requiring PAP therapy based on current published treatment recommendations.

Progression of obstructive sleep apnoea syndrome in Japanese patients

PURPOSE

The aggravation of obstructive sleep apnoea syndrome (OSAS) is reportedly associated with weight gain. The present study investigated the factors associated with worsening of respiratory functional parameters in Japanese OSAS patients who showed no body weight change during the follow-up period.

METHODS

A follow-up polysomnography (PSG) was performed in 82 patients with a mean of 7.5 years after the diagnostic PSG, and the apnoea-hypopnoea index (AHI), respiratory event duration, minimum percutaneous oxygen saturation (SpO2), baseline SpO2, and 3 % oxygen desaturation index (ODI) during sleep were compared between the two PSGs. Furthermore, factors associated with worsened AHI, respiratory event duration, and minimum SpO2 were investigated using logistic regression analysis.

RESULTS

No significant differences were observed in AHI, baseline SpO2, and 3 % ODI between the two PSGs. However, there was a significantly increased respiratory event duration and decreased minimum SpO2 observed. In addition, 17 patients had a ≥25 % AHI increase, and the age of 40-60 years and initial OSAS severity (mild and moderate) were the significantly associated factors. Age of ≥60 years and a baseline body mass index (BMI) of ≥25 kg/m(2) were significantly associated with prolonged respiratory event duration. The age of 40-60 years was significantly associated with decreased minimum SpO2.

CONCLUSIONS

Untreated middle-aged patients may be at a high risk for worsened AHI and SpO2 even without weight gain.

Comparison of the upper airway dynamics of oronasal and nasal masks with positive airway pressure treatment using cine magnetic resonance imaging

PURPOSE

It is known that oronasal masks are not as effective at opening the upper airway compared to nasal only continuous positive airway pressure (CPAP) masks in patients with sleep-disordered breathing. However, the physiological mechanism for this difference in efficacy is not known; although, it has been hypothesized to involve the retroglossal and/or retropalatal region of the upper airway. The objective of this study was to investigate differences in retroglossal and retropalatal anterior-posterior space with the use of oronasal vs. nasal CPAP masks using real-time cine magnetic resonance imaging (cMRI).

METHODS

Ten subjects (eight men, two women) with obstructive sleep apnea (OSA) were given cMRI with both nasal and oronasal CPAP masks. Each subject was imaged with each interface at pressures of 5, 10, and 15 cm of H2O, while in the supine position along the sagittal plane.

RESULTS

The oronasal mask produced significantly less airway opening in the retropalatal region of the upper airway compared to the nasal mask interface. During exhalation, mask style had a significant effect on anterior-posterior distance p = 0.016. No differences were found in the retroglossal region between mask styles.

CONCLUSIONS

Our study confirmed previous findings showing differences in treatment efficacy between oronasal and nasal mask styles. We have shown anatomic evidence that the nasal mask is more effective in opening the upper airway compared to the oronasal mask in the retropalatal region.

Prevalence of obstructive sleep apnea syndrome and CPAP adherence in the elderly Chinese population

BACKGROUND

This study assessed the prevalence of obstructive sleep apnea syndrome (OSAS) and CPAP adherence in the elderly Chinese in Hong Kong.

METHODS

We conducted a sleep questionnaire survey among the elders aged ≥60 years in the community centres followed by level 3 home sleep study (Embletta). Subjects with an apnea hypopnea index (AHI) ≥ 15/hr alone and those with AHI ≥ 5/hr plus either cardiovascular risk factors or Epworth Sleepiness Score (ESS) ≥ 10 were offered CPAP treatment.

RESULTS

Altogether 819 subjects were interviewed with mean (SD) age of 73.9 (7.5) years, BMI 24.2 (3.6) kg/m2, neck circumference 34.9 (3.4) cm and ESS 6.6 (5.2). Daytime sleepiness was reported by 72.4%, snoring loudly 5.1% and witnessed apnea 4%. Among 234 subjects who underwent home sleep study, 156 (66.7%), 102 (43.6%), 70 (29.9%) and 45 (19.2%) had AHI ≥ 5, ≥ 10, ≥ 15 and ≥ 20/hr respectively, with the prevalence increasing with age and BMI. In the sample, 149 subjects (63.7%) were classified as having OSAS, as defined by an AHI ≥ 5/hr with associated symptoms, involving 81 men (74.3%) and 68 women (54.4%). Neck circumference and snoring frequency were the only positive independent factors associated with the AHI and the diagnosis of OSAS. Among 141 subjects who were offered CPAP treatment, 30 accepted CPAP prescription with improvement of ESS and cognitive function over 12 months with CPAP usage of 4.2 (2.2) h/night.

CONCLUSION

This study showed a high prevalence of OSAS among the community elders in Hong Kong. Home CPAP acceptance was low but there was significant improvement of subjective sleepiness and cognitive function among those on CPAP treatment.

Compliance with continuous positive airway pressure (CPAP) therapy for obstructive sleep apnea among privately paying patients- a cross sectional study

Background

To evaluate the compliance, benefits and side effects associated with continuous positive airway pressure (CPAP) therapy among Pakistani patients treated for obstructive sleep apnea (OSA) in private sector.

Methods

Patients diagnosed to have OSA based on overnight study who were recommended for CPAP therapy, between 1998 and 2003, were evaluated by telephonic survey and review of hospital notes. Compliance, benefits and side effects associated with CPAP therapy were assessed.

Results

Out of 135 patients who were prescribed CPAP therapy, 75 could be contacted. Sixty (80%) started using CPAP within one month of diagnosis and 46 (61%) continued to use it long-term (beyond one year). Compliance with CPAP therapy was associated with higher body mass index, higher Epworth sleepiness scale score, history of witnessed apnea, and reduction in daytime sleepiness with CPAP therapy. OSA severity as assessed by apnea-hypopnea index did not affect compliance with CPAP therapy. Use of anti-depressants and CPAP induced sleep disturbances were associated with poor compliance with CPAP therapy.

Conclusions

Obesity, excessive daytime sleepiness, witnessed apnea and improvement of daytime symptoms following use of CPAP were predictors of improved compliance. Use of antidepressants and CPAP induced sleep disturbances were predictors of poor compliance.

A randomised controlled trial on the effect of mask choice on residual respiratory events with continuous positive airway pressure treatment

INTRODUCTION

It has been found that mask style can affect the amount of continuous positive airway pressure (CPAP) required to reduce an apnoea/hyponoea index (AHI) to < 5/h on a titration study. However, it was not previously known whether switching from one CPAP mask style to another post titration could affect the residual AHI with CPAP. The purpose of this study was to investigate the differences in residual AHI with CPAP treatment between oronasal and nasal masks.

METHODS

Twenty-one subjects (age mean (M)=62.9, body mass index (BMI) M=29.6 kg/m2) were randomised (14 subjects completed the protocol) to undergo an in-laboratory CPAP titration with either a nasal mask or an oronasal mask. Subjects were then assigned this mask for 3weeks of at-home CPAP use with the optimal treatment pressure determined on the laboratory study (CPAP M=8.4 cm of H2O). At the end of this 3-week period, data were collected from the CPAP machine and the subject was given the other mask to use with the same CPAP settings for the next 3weeks at home (if the nasal mask was given initially, the oronasal one was given later and vice versa). On completion of the second 3-week period, data on residual AHI were again collected and compared with the first 3-week period on CPAP.

RESULTS

A Wilcoxon Signed-Rank Test (two-tailed) revealed that residual AHI with CPAP treatment was significantly higher with the oronasal compared with the nasal mask (z = -3.296, p<0.001). All 14 subjects had a higher residual AHI with the oronasal versus nasal mask, and 50% of the subjects had a residual AHI >10/h in the oronasal mask condition, even though all of these subjects were titrated to an AHI of < 5/h in the laboratory.

CONCLUSION

A higher residual AHI was seen in all patients with the use of an oronasal mask compared with a nasal mask. Switching to an oronasal mask post titration results in an increase in residual AHI with CPAP treatment, and pressure adjustment may be warranted.

Prevalence of obstructive sleep apnea in Asian adults: a systematic review of the literature

Background

Obstructive sleep apnea (OSA) is a common disease, affecting approximately 2% of women and 4% of men residing in Western communities. No systematically reviewed data are available about the prevalence of this disease in Asia, the most heavily populated continent.

Methods

PubMed/Medline, Scopus and Google Scholar were searched for articles published from 1993 to May 2012 that reported the prevalence of OSA diagnosed via sleep monitoring and the prevalence of patients at risk for OSA as assessed by symptomatology and/or sleep questionnaires. We have also searched abstract database of major pulmonary and sleep scientific societies for relevant abstracts presented from 2010 to 2012. The following inclusion criteria were used: articles published in English, age ≥ 18 years, ≥ 100 participants in studies using sleep monitoring for the diagnosis of OSA, ≥ 300 participants in studies using questionnaires to detect patients at high risk for OSA. Exclusion criteria: duplicate publications, studies reporting the prevalence of central sleep apnea only, hospital based studies as well as studies assessing OSA prevalence among patients with resistant arterial hypertension, chronic kidney disease, heart failure and in patients with concomitant neurological disease.

Results

Twenty four articles were found to meet the inclusion criteria, covering 47,957 subjects (26,042 men and 21,915 women) and four relevant abstracts were noted. OSA prevalence ranged from 3.7% to 97.3%. Male gender, older age, a higher BMI and waist to hip ratio, greater neck circumference, arterial hypertension, smoking, snoring and daytime sleepiness were associated with OSA. Sample size, difference between the populations studied and the fact that some works included patients with a high pre-test probability of OSA explain the difference in prevalence rates.

Conclusion

This systematic review highlights the lack of data regarding the prevalence of OSA in Asians. Only a few studies provide an approximate estimate of the OSA burden in some Asian communities.

Investigation of obstructive sleep apnoea syndrome prevalence among long-distance drivers from Zonguldak, Turkey

BACKGROUND

The aim of this study was to assess the prevalence of Obstructive sleep apnoea syndrome (OSAS) in long-distance drivers located in the Zonguldak area and to show the correlation between OSAS and traffic accidents.

METHODS

In this study, 241 long-distance drivers who were residents of Zonguldak province were interviewed face-to-face and a questionnaire regarding OSAS symptoms, occupational histories, and numbers of accidents was administered. Body mass measurements were also taken from participants. Patients who exhibited evidence of OSAS underwent polysomnography (PSG).

RESULTS

Snoring was detected in 56% out of all participants, daytime sleepiness was observed in 26.6% and apnoea in 11.6%. All-night PSG was applied to 42 participants who had a high probability of clinical OSAS. Among these, eight had an apnoea-hypopnoea index (AHI) < 5. The prevalence of OSAS was 14.1%. There was a significant relationship between the ratio of traffic accidents per professional years and AHI (r = 0.571; p < 0.005).

CONCLUSIONS

OSAS prevalence was higher among long-distance drivers in the Zonguldak region. Disease severity was directly proportional to traffic-accident risk, and thus represents a serious social problem.

The impact of work nature, lifestyle, and obesity on health-related quality of life in Chinese professional drivers

OBJECTIVE

To assess the association of work nature, lifestyle and obesity with health-related quality of life (HRQOL) in professional drivers.

METHODS

A total of 3376 Chinese professional drivers aged 18 to 70 years were recruited to assess the HRQOL by SF-12 summary scores (Physical Component Summary [PCS]; Mental Component Summary [MCS]), and collect data for work nature, lifestyle, and body mass index. Factors associated with HRQOL were examined by multiphase regression analyses.

RESULTS

Professional drivers reported poorer physical and mental HRQOL than the general population. Shift work and lorry driving had significant negative effect on HRQOL. Obesity was associated with lower PCS but higher MCS.

CONCLUSIONS

HRQOL of professional drivers tended to be low, especially among lorry drivers and shift drivers. Health intervention programs should promote regular exercise, healthy eating, no smoking, and weight control, which are modifiable factors improving HRQOL.

The efficacy of three different mask styles on a PAP titration night

BACKGROUND

This study compared the efficacy of three different masks, nasal pillows, nasal masks and full face (oronasal) masks, during a single night of titration with continuous positive airway pressure (CPAP).

METHODS

Fifty five subjects that included men (n=33) and women (n=22) were randomly assigned to one of three masks and underwent a routine titration with incremental CPAP applied through the different masks.

RESULTS

CPAP applied through the nasal pillows and nasal mask was equally effective in treating mild, moderate, and severe sleep apnea. However, CPAP applied through the oronasal mask required a significantly higher pressure compared to nasal masks to treat moderately severe (2.8 cm of H(2)O ± 2.1 SD) and severe (6.0 cm of H(2)O ± 3.2 SD) obstructive sleep apnea.

CONCLUSION

CPAP applied with either nasal mask was effective in treating mild, moderate, and severe sleep apnea. The oronasal mask required significantly higher pressures in subjects with moderate to severe disease. Therefore, when changing from a nasal to an oronasal mask, a repeat titration is required to ensure effective treatment of sleep apnea, especially in patients with moderate to severe disease.

Neurocognitive impairment in Chinese patients with obstructive sleep apnoea hypopnoea syndrome

BACKGROUND AND OBJECTIVE

Sleep-disordered breathing is known to be associated with impairment in cognitive function. The aim of this study was to characterize neurocognitive impairment in a cohort of Chinese patients with varying severities of obstructive sleep apnoea hypopnoea syndrome (OSAHS), and to develop a sensitive instrument for routine screening of cognitive impairment.

METHODS

Eligible patients (n = 394) were categorized into a primary snoring group, and mild, moderate and severe OSAHS groups, based on assessment of AHI. The Montreal Cognitive Assessment (MoCA) and the Mini-Mental State Examination (MMSE) questionnaires were administered to assess cognitive function, and the correlations between questionnaire scores and clinical and polysomnographic parameters were further evaluated by stepwise multivariate regression.

RESULTS

MoCA scores decreased progressively across the spectrum from primary snoring to severe OSAHS. Importantly, mild neurocognitive impairment as defined by a MoCA score <26 was more common in the moderate (38.6%) and severe (41.4%) OSAHS groups than in the mild OSAHS (25.0%) and primary snoring (15.2%) groups. In contrast, MMSE scores were largely normal and comparable among all four groups. Evaluation of MoCA subdomains further revealed selective reduction in memory/delayed recall, visuospatial and executive function, and attention span in the severe OSAHS group compared with the other groups. Stepwise multivariate regression analysis demonstrated that MoCA scores correlated significantly with lowest oxygen saturation (L-SaO(2) ) and years of education.

CONCLUSIONS

Neurocognitive impairment is common in patients with OSAHS. The MoCA is a brief and sensitive tool for the assessment of cognitive impairment in OSAHS patients, whose performance on the MMSE is in the normal range.

Excessive daytime sleepiness among Japanese public transportation drivers engaged in shiftwork

OBJECTIVE

To explore the actual condition of sleep disorders underlying subjective excessive daytime sleepiness (EDS) among train and bus drivers engaged in shiftwork.

METHODS

This study targeted 3109 public transportation drivers. Clinical diagnoses were made based on 147 drivers who claimed to have subjective EDS, and 285 drivers who were judged to have obstructive sleep apnea syndrome (OSAS), based on the screening process.

RESULTS

Among these subjects, the prevalence of OSAS was 3.7% and that of shiftwork disorder (SWD) was 1.5%. SWD was common among drivers who had EDS (32.7% of drivers with EDS), and their EDS severity was higher than that of OSAS drivers. The drivers with SWD were mostly young and neither obese nor hypertensive.

CONCLUSIONS

Encouraging awareness of SWD and OSAS could be necessary to prevent sleepiness-related accidents.

How treatment affects cognitive deficits in patients with sleep disorders: methodological issues and results

Sleep disorders are frequently associated with impaired performance although the type and extent of cognitive deficits varies widely between different types of sleep disorders. Treatment is expected to ameliorate these deficits. However, cognitive functioning and its change with treatment depend on numerous factors. In this chapter we discuss methodological issues, including test selection, and person-specific, task-specific and environmental factors that influence cognitive functioning. In addition, features of study design and sampling strategies are discussed. The chapter ends with a short overview of routes by which treatment may affect cognition in sleep-disordered patients.

A randomized cross-over study of auto-continuous positive airway pressure versus fixed-continuous positive airway pressure in patients with obstructive sleep apnoea

BACKGROUND AND OBJECTIVES

To compare the efficacy of auto-CPAP (AutoSet Spirit, ResMed) versus fixed-CPAP (S6 Elite, ResMed) in improving daytime sleepiness, health status, objective compliance and the ultimate treatment preference in patients with severe OSA.

METHODS

The study recruited 43 subjects aged 18-65 years with newly diagnosed severe OSA (AHI >30/h). Patients were initially treated with either auto-CPAP or fixed-CPAP for 2 months and then crossed over after a washout period of 1 week for another 2 months.

RESULTS

The study was completed by 41 patients. Results are presented as mean (SE). Use of auto-CPAP in the first and the second month was significantly higher than that of fixed-CPAP [129.7 (9.9) and 130.5 (10.7) h vs 115.2 (9.5) and 113.2 (9.4) h, P = 0.04 and 0.01], whereas mean hourly use per night was 4.3 and 4.4 h versus 3.8 and 3.7 h, respectively. The Epworth sleepiness scores improved after 1 month in both treatments (13.4 to 8.5 and 8.2, P < 0.01 for both). The Sleep apnoea quality of life index improved in the first month in both compared with baseline [4.6 (0.2) to 5.0 (0.2) for auto-CPAP and 4.9 (0.2) for fixed-CPAP, P = 0.01 and 0.04, respectively], with no difference between the two treatments. Nine and 30 patients preferred auto-CPAP and fixed-CPAP, respectively, at the end of the trial, whereas 14 and 25 patients would have chosen the same treatments if cost had not been a consideration.

CONCLUSIONS

Auto-CPAP and fixed-CPAP were equally effective in improving symptoms and health status in patients with severe OSA. Usage was higher with auto-CPAP, but more patients ultimately chose fixed-CPAP.

Sonographic measurement of lateral parapharyngeal wall thickness in patients with obstructive sleep apnea

INTRODUCTION

Lateral parapharyngeal wall (LPW) thickness may be a predominant anatomic factor causing airway narrowing in apneic subjects. In this study, we explored sonographic measurement of the LPW thickness and compared the results with LPW thickness measured by magnetic resonance imaging (MRI). We also investigated the association between sonographic measurement of LPW thickness and apnea-hypopnea index (AHI).

METHOD

Seventy-six patients with suspected obstructive sleep apnea (OSA) underwent ultrasound examination of LPW thickness after overnight polysomnography. Fifteen out of 76 subjects also participated in correlation and reliability studies of sonographic and MRI measurements of LPW thickness.

RESULTS

There was good correlation between measurements of LPW thickness on ultrasound and MRI (r = 0.78, P = 0.001), although Bland-Altman analysis indicated overestimation of LPW thickness by ultrasound, when compared with the LPW as measured by MRI. The sonographic measurement of LPW thickness had high reproducibility, with intraclass correlation coefficients of 0.90 and 0.97 for intraoperator and interoperator reliability, respectively. Fifty-eight subjects with significant OSA (AHI > or = 10/h) had a higher body mass index, larger neck circumference, and greater LPW thickness measured by ultrasound than those (n = 18) with an AHI of less than 10 per hour. LPW thickness had a positive correlation with AHI on univariate analysis (r = 0.37, P = 0.001). On multivariate analysis, LPW thickness had a positive independent association with AHI after adjustment for age, sex, neck circumference, and body mass index. The positive association of LPW thickness with AHI remained significant in both univariate and multivariate analyses of men only (n = 62).

CONCLUSIONS

Sonographic measurement of LPW thickness is a novel and reliable technique and had good correlations with measurement by MRI and the severity of OSA. Ultrasound may provide an alternative imaging modality with easy accessibility and lower cost in OSA research.