Impact of treating obesity hypoventilation syndrome on body mass index.

STUDY OBJECTIVES: To evaluate the impact of positive airway pressure (PAP) therapy on body mass index (BMI) in patients with obesity hypoventilation syndrome (OHS) associated with obstructive sleep apnea (OSA). METHODS: A systematic review using the following terms: "obesity hypoventilation syndrome" AND "treatment" AND "randomized" using Cochrane Central Register of Controlled Trials, Medline and Web of Science was performed from the first data available until February 10, 2023. The inclusion criteria were: (1) original article; (2) adult OHS with concomitant OSA (apnea-hypopnea index or AHI ≥5 events/h); (3) randomized trial with PAP arm and standard care (control); (4) BMI evaluation at baseline and after the first months. We performed an individual participant data meta-analysis of randomized controlled trials. RESULTS: Our initial search retrieved 32 articles and 3 randomized studies fulfilled study criteria and were included in the final analysis, leading to a total of 342 participants. Patients were predominantly females (62%) and had OHS associated with at least mild OSA. As compared to baseline, a decrease in BMI was observed at study endpoint but this difference was not different intergroups (-0.50 ± 1.49 and -0.50 ±1.83, in control and PAP groups respectively (p=0.939)). Weight change was not associate with PAP adherence, OSA severity or use of supplemental oxygen. CONCLUSIONS: In contrast to treatment of eucapnic OSA with PAP that is associated with weight gain, treatment of OSA+OHS patients with or without PAP is associated with weight loss. Future studies are necessary to elucidate the mechanism by which weight loss occurs.

Effects of exercise training on autonomic modulation and mood symptoms in patients with obstructive sleep apnea.

We evaluated the effects of exercise training (ET) on the profile of mood states (POMS), heart rate variability, spontaneous baroreflex sensitivity (BRS), and sleep disturbance severity in patients with obstructive sleep apnea (OSA). Forty-four patients were randomized into 2 groups, 18 patients completed the untrained period and 16 patients completed the exercise training (ET). Beat-to-beat heart rate and blood pressure were simultaneously collected for 5 min at rest. Heart rate variability (RR interval) was assessed in time domain and frequency domain (FFT spectral analysis). BRS was analyzed with the sequence method, and POMS was analyzed across the 6 categories (tension, depression, hostility, vigor, fatigue, and confusion). ET consisted of 3 weekly sessions of aerobic exercise, local strengthening, and stretching exercises (72 sessions, achieved in 40±3.9 weeks). Baseline parameters were similar between groups. The comparisons between groups showed that the changes in apnea-hypopnea index, arousal index, and O2 desaturation in the exercise group were significantly greater than in the untrained group (P<0.05). The heart rate variability and BRS were significantly higher in the exercise group compared with the untrained group (P<0.05). ET increased peak oxygen uptake (P<0.05) and reduced POMS fatigue (P<0.05). A positive correlation (r=0.60, P<0.02) occurred between changes in the fatigue item and OSA severity. ET improved heart rate variability, BRS, fatigue, and sleep parameters in patients with OSA. These effects were associated with improved sleep parameters, fatigue, and cardiac autonomic modulation, with ET being a possible protective factor against the deleterious effects of hypoxia on these components in patients with OSA.

Effects of exercise training on autonomic modulation and mood symptoms in patients with obstructive sleep apnea

We evaluated the effects of exercise training (ET) on the profile of mood states (POMS), heart rate variability, spontaneous baroreflex sensitivity (BRS), and sleep disturbance severity in patients with obstructive sleep apnea (OSA). Forty-four patients were randomized into 2 groups, 18 patients completed the untrained period and 16 patients completed the exercise training (ET). Beat-to-beat heart rate and blood pressure were simultaneously collected for 5 min at rest. Heart rate variability (RR interval) was assessed in time domain and frequency domain (FFT spectral analysis). BRS was analyzed with the sequence method, and POMS was analyzed across the 6 categories (tension, depression, hostility, vigor, fatigue, and confusion). ET consisted of 3 weekly sessions of aerobic exercise, local strengthening, and stretching exercises (72 sessions, achieved in 40±3.9 weeks). Baseline parameters were similar between groups. The comparisons between groups showed that the changes in apnea-hypopnea index, arousal index, and O2 desaturation in the exercise group were significantly greater than in the untrained group (P<0.05). The heart rate variability and BRS were significantly higher in the exercise group compared with the untrained group (P<0.05). ET increased peak oxygen uptake (P<0.05) and reduced POMS fatigue (P<0.05). A positive correlation (r=0.60, P<0.02) occurred between changes in the fatigue item and OSA severity. ET improved heart rate variability, BRS, fatigue, and sleep parameters in patients with OSA. These effects were associated with improved sleep parameters, fatigue, and cardiac autonomic modulation, with ET being a possible protective factor against the deleterious effects of hypoxia on these components in patients with OSA.

Restless legs syndrome in Wilson's disease: frequency, characteristics, and mimics.

OBJECTIVE: To determine characteristics, clinical significance, frequency, and mimics of restless legs syndrome (RLS) in a cohort of Wilson's disease (WD, n = 42/f = 18), compared to healthy, matched controls. MATERIALS AND METHODS: Structured clinical interviews (patients and caregiving family members), repeated neurological examinations (afternoon and presleep), comprehensive laboratory tests, WD-, RLS-, and sleep-specific rating scales, and video-polysomnography. RESULTS: Thirteen patients with WD (13/42 = 31.0%) clearly fulfilled the five diagnostic criteria of RLS; in eight patients (19.1%), the burden of RLS was clinically significant. The RLS was of moderate severity, equally distributed among sexes, manifested mainly in the evening and before falling asleep, and had developed mostly after clinical manifestation of WD (time elapsed 10.2 ± 14.5 years), still at a young mean age (27.5 ± 11.5 years). The known RLS-associated features were absent (normal iron and kidney parameters) or rare (positive family history, polyneuropathy). Compared to WD patients without RLS, patients with RLS were significantly elder and had suffered longer from WD. WD-specific RLS mimics as well as RLS confounding motor comorbidities (dystonia, tremor, chorea) were frequent and a diagnostic challenge; in difficult cases, the differentiation was reached by clinical observation of the motor behavior in the evening or at nighttime. CONCLUSION: RLS was frequent in this cohort of WD and might be causally related to WD. RLS should be included in the diagnostic work-up of WD. In complex motor disorders, differential diagnosis of RLS might require evening/nighttime examination and video-polysomnography. In WD patients with a clinically significant RLS, treatment with dopaminergic substances may be considered.

Timing and quality of sleep in a rural Brazilian family-based cohort, the Baependi Heart Study.

Sleep is modulated by several factors, including sex, age, and chronotype. It has been hypothesised that contemporary urban populations are under pressure towards shorter sleep duration and poorer sleep quality. Baependi is a small town in Brazil that provides a window of opportunity to study the influence of sleep patterns in a highly admixed rural population with a conservative lifestyle. We evaluated sleep characteristics, excessive daytime sleepiness, and chronotype using the Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale and Morningness-Eveningness Questionnaire questionnaires, respectively. The sample consisted of 1,334 subjects from the Baependi Heart study (41.5% male; age: 46.5 ± 16.2 y, range: 18-89 years). Average self-reported sleep duration was 07:07 ± 01:31 (bedtime 22:32 ± 01:27, wake up time: 06:17 ± 01:25 hh:min), sleep quality score was 4.9 + 3.2, chronotype was 63.6 ± 10.8 and daytime sleepiness was 7.4 ± 4.8. Despite a shift towards morningness in the population, chronotype remained associated with reported actual sleep timing. Age and sex modulated the ontogeny of sleep and chronotype, increasing age was associated with earlier sleep time and shorter sleep duration. Women slept longer and later, and reported poorer sleep quality than men (p < 0.0001). This study provides indirect evidence in support of the hypothesis that sleep timing was earlier prior to full urbanisation.

CPAP and survival in moderate-to-severe obstructive sleep apnoea syndrome and hypoxaemic COPD.

Obstructive sleep apnoea syndrome (OSAS) often coexists in patients with chronic obstructive pulmonary disease (COPD). The present prospective cohort study tested the effect of OSAS treatment with continuous positive airway pressure (CPAP) on the survival of hypoxaemic COPD patients. It was hypothesised that CPAP treatment would be associated with higher survival in patients with moderate-to-severe OSAS and hypoxaemic COPD receiving long-term oxygen therapy (LTOT). Prospective study participants attended two outpatient advanced lung disease LTOT clinics in São Paulo, Brazil, between January 1996 and July 2006. Of 603 hypoxaemic COPD patients receiving LTOT, 95 were diagnosed with moderate-to-severe OSAS. Of this OSAS group, 61 (64%) patients accepted and were adherent to CPAP treatment, and 34 did not accept or were not adherent and were considered not treated. The 5-yr survival estimate was 71% (95% confidence interval 53-83%) and 26% (12-43%) in the CPAP-treated and nontreated groups, respectively (p<0.01). After adjusting for several confounders, patients treated with CPAP showed a significantly lower risk of death (hazard ratio of death versus nontreated 0.19 (0.08-0.48)). The present study found that CPAP treatment was associated with higher survival in patients with moderate-to-severe OSAS and hypoxaemic COPD receiving LTOT.

Ethnicity as a risk factor for obstructive sleep apnea: comparison of Japanese descendants and white males in São Paulo, Brazil.

Some studies showed that Asians with obstructive sleep apnea (OSA) are thinner than Caucasians. Because obesity is a major risk factor for OSA, it was concluded that Asians are predisposed to OSA. However, body fat composition varies for a same body mass index (BMI) according to ethnicity. We firstly compared anthropometric characteristics, symptoms and associated disorders in all consecutive male Japanese descendants and white males with OSA referred for polysomnography. In a second analysis, all Japanese descendants were compared to a subgroup of white males, matched for apnea/hypopnea index and age. In the first analysis, age, symptoms, OSA severity and co-morbidities were similar among Japanese descendants (N = 54) and white patients (N = 466). However, Japanese descendants had a lower BMI than white patients: 27.1 (25.5-28.4) vs 29.4 (26.5-33.0) kg/m(2), respectively (P < 0.001). In the second analysis, Japanese descendants had a lower BMI than white patients (P < 0.001). Multiple linear regression considering the entire group revealed that age, BMI, neck circumference, Epworth sleepiness scale, ethnicity and %REM sleep were independent predictors for apnea/hypopnea index (P < 0.001). Ethnicity was no longer significantly associated with OSA severity when we adopted the World Health Organization criteria for obesity (> or =25 and 30 kg/m(2) among Japanese descendants and white males, respectively). Japanese descendants with OSA have a lower BMI than white subjects of similar severity. However, ethnicity was not associated with OSA severity when an ethnical difference in obesity criteria was respected. Our data suggest that Japanese descendants are not predisposed to OSA.

Ethnicity as a risk factor for obstructive sleep apnea: comparison of Japanese descendants and white males in São Paulo, Brazil

Some studies showed that Asians with obstructive sleep apnea (OSA) are thinner than Caucasians. Because obesity is a major risk factor for OSA, it was concluded that Asians are predisposed to OSA. However, body fat composition varies for a same body mass index (BMI) according to ethnicity. We firstly compared anthropometric characteristics, symptoms and associated disorders in all consecutive male Japanese descendants and white males with OSA referred for polysomnography. In a second analysis, all Japanese descendants were compared to a subgroup of white males, matched for apnea/hypopnea index and age. In the first analysis, age, symptoms, OSA severity and co-morbidities were similar among Japanese descendants (N = 54) and white patients (N = 466). However, Japanese descendants had a lower BMI than white patients: 27.1 (25.5-28.4) vs 29.4 (26.5-33.0) kg/m², respectively (P < 0.001). In the second analysis, Japanese descendants had a lower BMI than white patients (P < 0.001). Multiple linear regression considering the entire group revealed that age, BMI, neck circumference, Epworth sleepiness scale, ethnicity and percentREM sleep were independent predictors for apnea/hypopnea index (P < 0.001). Ethnicity was no longer significantly associated with OSA severity when we adopted the World Health Organization criteria for obesity (≥25 and 30 kg/m² among Japanese descendants and white males, respectively). Japanese descendants with OSA have a lower BMI than white subjects of similar severity. However, ethnicity was not associated with OSA severity when an ethnical difference in obesity criteria was respected. Our data suggest that Japanese descendants are not predisposed to OSA.

Breathing disorders in congestive heart failure: gender, etiology and mortality.

We investigated the relationship between sleep-disordered breathing (SDB) and Cheyne-Stokes respiration (CSR) while awake as well as mortality. Eighty-nine consecutive outpatients (29 females) with congestive heart failure (CHF; left ventricular ejection fraction, LVEF <45%) were prospectively evaluated. The presence of SDB and of CSR while awake before sleep onset was investigated by polysomnography. SDB prevalence was 81 and 56%, using apnea-hypopnea index cutoffs >5 and >15, respectively. CHF etiologies were similar according to the prevalence of SDB and sleep pattern. Males and females were similar in age, body mass index, and LVEF. Males presented more SDB (P = 0.01), higher apnea-hypopnea index (P = 0.04), more light sleep (stages 1 and 2; P < 0.05), and less deep sleep (P < 0.001) than females. During follow-up (25 +/- 10 months), 27% of the population died. Non-survivors had lower LVEF (P = 0.01), worse New York Heart Association (NYHA) functional classification (P = 0.03), and higher CSR while awake (P < 0.001) than survivors. As determined by Cox proportional model, NYHA class IV (RR = 3.95, 95%CI = 1.37-11.38, P = 0.011) and CSR while awake with a marginal significance (RR = 2.96, 95%CI = 0.94-9.33, P = 0.064) were associated with mortality. In conclusion, the prevalence of SDB and sleep pattern of patients with Chagas' disease were similar to that of patients with CHF due to other etiologies. Males presented more frequent and more severe SDB and worse sleep quality than females. The presence of CSR while awake, but not during sleep, may be associated with a poor prognosis in patients with CHF.

Breathing disorders in congestive heart failure: gender, etiology and mortality

We investigated the relationship between sleep-disordered breathing (SDB) and Cheyne-Stokes respiration (CSR) while awake as well as mortality. Eighty-nine consecutive outpatients (29 females) with congestive heart failure (CHF; left ventricular ejection fraction, LVEF <45 percent) were prospectively evaluated. The presence of SDB and of CSR while awake before sleep onset was investigated by polysomnography. SDB prevalence was 81 and 56 percent, using apnea-hypopnea index cutoffs >5 and >15, respectively. CHF etiologies were similar according to the prevalence of SDB and sleep pattern. Males and females were similar in age, body mass index, and LVEF. Males presented more SDB (P = 0.01), higher apnea-hypopnea index (P = 0.04), more light sleep (stages 1 and 2; P < 0.05), and less deep sleep (P < 0.001) than females. During follow-up (25 ± 10 months), 27 percent of the population died. Non-survivors had lower LVEF (P = 0.01), worse New York Heart Association (NYHA) functional classification (P = 0.03), and higher CSR while awake (P < 0.001) than survivors. As determined by Cox proportional model, NYHA class IV (RR = 3.95, 95 percentCI = 1.37-11.38, P = 0.011) and CSR while awake with a marginal significance (RR = 2.96, 95 percentCI = 0.94-9.33, P = 0.064) were associated with mortality. In conclusion, the prevalence of SDB and sleep pattern of patients with Chagas' disease were similar to that of patients with CHF due to other etiologies. Males presented more frequent and more severe SDB and worse sleep quality than females. The presence of CSR while awake, but not during sleep, may be associated with a poor prognosis in patients with CHF.

Short sleep is associated with obesity among truck drivers.

Recent studies suggest that short-sleep duration is independently associated with obesity in the general population. The population of truck drivers is of particular interest, because they frequently work irregular shifts that in turn are associated with short-sleep duration. In addition, truck drivers have a high prevalence of sedentary habits, poor diet, and obesity. The present study aimed at verifying the association between sleep patterns and factors associated with obesity in this population. The study sample consisted in 4,878 truck drivers who participated in a campaign promoted by a highway company in the State of São Paulo, Brazil. This campaign offered highway truck drivers a medical and laboratorial evaluation. The truck drivers completed a questionnaire concerning demographic data, sleep duration, consumption of medications, and medical problems, such as diabetes, cardiopathy, and hypertension; as well as the Berlin questionnaire, which is able to discriminate low and high risk for obstructive sleep apnea. Blood samples were collected to measure glucose and cholesterol levels. Also, body weight and height were registered to calculate the body mass index (BMI). The mean age (+/-SD) of the truck drivers studied was 40+/-10 years. Out of the truck drivers analyzed, 28.3% (n = 1,379) had a BMI > or =30.0 Kg/m2 (obesity). Among the 4,878 drivers included in the study, 1,199 (24.6%) were on medications and 334 (6.8%) were diabetic. Drivers (26.9%) with the greater BMI had a short sleep length. The independent factors associated with obesity were sleep duration <8 h/day (OR = 1.24), age >40 years (OR = 1.20), glucose levels >200 (OR = 2.02), cholesterol levels >240 (OR = 1.57), snoring (OR = 1.74), and hypertension (OR = 2.14). Smoking was not associated with obesity (OR = 0.69), and diabetes was considered a control variable. In conclusion, this study supports the hypothesis that short sleep duration as well as age >40 years are independently associated with obesity. This particular combination (short-sleep duration and obesity) is independently associated with several healthcare problems, including high levels of cholesterol, glucose, snoring, and hypertension. However, due to the cross-sectional nature of this study, no cause-effect relationship can be drawn from these results.

Phenotypic characteristics associated with hypertension in patients with obstructive sleep apnea.

Obstructive sleep apnea (OSA) causes secondary hypertension. However, the reasons why the prevalence of hypertension among OSA patients varies widely (35-70%) are not clear. We sought to investigate the phenotypic characteristics of patients with and without hypertension among OSA patients who were matched for disease severity. We studied 152 OSA patients (76 normotensive and 76 hypertensive) diagnosed by polysomnography. Detailed phenotypic characteristics, including laboratorial analysis, were determined in all patients. Univariate analysis followed by multiple logistic regression analysis was used to identify variables that were independently associated with hypertension. The apnea-hypopnea index in normotensive and hypertensive patients was similar (48+/-26 and 48+/-26 events/h, respectively) as well as minimum arterial oxygen saturation (76+/-10 and 75+/-10%, respectively) and total sleep time with oxyhaemoglobin saturation <90% (25+/-25 and 28+/-26%, respectively). Hypertensive patients were older (57+/-11 vs 47+/-12 years; P<0.001), had a higher body mass index (BMI; 34+/-7 vs 30+/-5 kg/m(2); P<0.001), had a higher frequency of women (37 vs 8%; P<0.001), had a higher incidence of diabetes (25 vs 6%; P=0.002) and a higher family history of hypertension (75 vs 42%; P=0.01) than did the normotensive patients. Multiple logistic regression analysis indicated that age (P=0.004), familial history of hypertension (P=0.004), BMI (P=0.04) and female sex (P=0.03) were the independent variables associated with hypertension. We concluded that increasing age and BMI, familial history of hypertension as well as female gender are phenotypic characteristics associated with hypertension among OSA patients with similar disease severity.

Effects of acute hypovolaemia by furosemide on tracheal transepithelial potential difference and mucus in dogs.

Furosemide is a potent diuretic that affects water transfer across the respiratory epithelium, which is closely related to the transepithelial potential difference (PD). Water is a critical factor that determines mucus transport; an important lung defence mechanism that removes particles and microorganisms from the respiratory system. The aim of the present study was to investigate the acute effects of furosemide and hypovolaemia on tracheal PD and mucus properties. A total of 36 male mixed-breed dogs were submitted to anaesthesia, mechanical ventilation and haemodynamic monitoring. They were randomly assigned to three groups consisting of: a control group, a furosemide (40 mg i.v.) + hypovolaemia group, and a furosemide (40 mg i.v.) + volume replacement group. Tracheal PD and mucus samples were collected at time 0, 1 and 2 h after intervention. Mucus properties were analysed by means of a magnetic microrheometer and in vitro mucociliary transportability on the frog palate. Compared to controls, furosemide decreased PD to intermediate values, and only significantly when associated with hypovolaemia (-13+/-5 and -8+/-2 mV, time 0 and 2 h, respectively). In addition to the direct effect of furosemide, these results indicate that hypovolaemia also affects ion transport in the tracheal membrane. Furosemide and hypovolemia have no acute effects on respiratory mucus properties.

High risk for obstructive sleep apnea in truck drivers estimated by the Berlin questionnaire: prevalence and associated factors.

The health issues that attract our attention when analyzing the truck driver population are the high prevalence of sedentary habits, inadequate diet, obesity, and proportion of hypertensive. All these are either considered risk factors for or a consequence of Obstructive Sleep Apnea (OSA). The objective of this study was to investigate the risk for OSA among 10,101 truck drivers and to correlate it with potentially related factors, such as serum glucose and cholesterol levels, smoking habits, alcohol and drug consumption, and self-reported physical activity. The drivers were invited to participate in the campaign "Saúde na Boléia" (Health Behind the Wheel) promoted by a Brazilian company responsible for the maintenance of approximately 360km of roads in the country. Drivers who spontaneously stopped at the campaign booths placed along the roads were invited to answer a questionnaire covering sociodemographic data such as age, alcohol, and drug consumption. All participants completed a Berlin Questionnaire and were classified as low- or high-risk subjects for OSA based on questions about snoring, tiredness during the day, and the presence of hypertension or obesity. Blood collection was accomplished at the same site by nurses and/or nursing students collaborating with the campaign for subsequent laboratory studies. Approximately 26% of the truck drivers were found to be at high-risk group for OSA. An adjusted multiple logistic model found the independent risk factors of smoking (OR=1.16; p=0.014) and drug use (OR= 1.32; p < 0.0001) were associated with high risk for OSA. The presence of self-reported occasional (OR=0.62; p<0.0001) and regular (OR=0.53; p < 0.0001) physical activity was found to be an independent factor protective of OSA. Educational programs, including ones aimed at improving one's health habits, such as engagement in physical exercise, should be considered in the development of initiatives to reduce the risk for OSA among the truck driver population.

Relationship of carbon dioxide tension in arterial blood to pulmonary wedge pressure in heart failure.

Hypocapnia contributes to the genesis of Cheyne-Stokes respiration and central sleep apnoea in patients with congestive heart failure (CHF) and is associated with increased mortality. However, the cause of hypocapnia in patients with chronic stable CHF is unknown. Since pulmonary congestion can induce hyperventilation via stimulation of pulmonary vagal afferents, the present study tested the hypothesis that in patients with CHF (carbon dioxide tension in arterial blood (Pa,CO2)) is inversely related to pulmonary capillary wedge pressure (PCWP), and that alterations in PCWP would cause inverse changes in Pa,CO2. In 11 CHF patients undergoing diagnostic cardiac catheterization, haemodynamic variables and arterial blood gas tensions were measured simultaneously at baseline. In three patients, these measurements were repeated after coronary angiographic dye infusion and nitroglycerine infusion. At baseline, Pa,CO2 correlated inversely with PCWP (r=-0.80, p=0.003). In the three patients in whom multiple measurements were made, acute alterations in PCWP caused inversely proportional changes in Pa,CO2. The present study concludes that in patients with congestive heart failure, pulmonary capillary wedge pressure is an important determinant of carbon dioxide tension in arterial blood. These findings imply that hypocapnia in patients with chronic stable congestive heart failure is a respiratory manifestation of elevated left ventricular filling pressures.