The NH-OSA score in prediction of clinically significant obstructive sleep apnea among the Thai population: derivation and validation studies.

BACKGROUND: Diagnosis of obstructive sleep apnea requires polysomnography which has limited availability. We aimed to develop and validate a risk score in predicting clinically significant OSA among the Thai population. METHODS: We reviewed polysomnographic studies performed in adults diagnosed with OSA in King Chulalongkorn Memorial Hospital from 2017 to 2019. 1798 and 450 patients were randomly enrolled in development and validation cohorts, respectively. A risk score was developed using multiple factor analysis and logistic regression. The NH-OSA score was externally validated at the Bangkok Christian Hospital. We compared its performance to existing screening scores (STOP-BANG, Berlin Questionnaire, Epworth Sleepiness Scale (ESS), and NoSAS score). RESULT: The NH-OSA score allocates 1 point for having neck circumference ≥ 13 inches (in women) or 15 inches (in men), 4 points for the presence of hypertension, 3 or 5 or 7 points for having a body mass index of 23-24.9, 25-30, ≥ 30 kg/m2, respectively, 9 points for the presence of moderate or severe snoring, and 5 points for age ≥ 40 years. With a cutoff value at 14 points, the sensitivity and specificity were 82.1% and 68.7%, respectively. The AUC was 0.75 (0.73-0.78). Both internal and external validation study revealed high AUC of 0.74 (0.68-0.80) and 0.75 (0.60-0.90), respectively. These were greater when compared to STOP-BANG, Berlin Questionnaire, ESS, and NoSAS score. CONCLUSION: NH-OSA is a newly developed tool which has good performance in predicting clinically significant OSA with high validity among the Thai population. It could help screen patients at risk of OSA for further investigation.

Critical care management of pulmonary arterial hypertension in pregnancy: the pre-, peri- and post-partum stages.

The mortality rate of pulmonary hypertension in pregnancy is 25%-56%. Pulmonary arterial hypertension is the highest incidence among this group, especially in young women. Despite clear recommendation of pregnancy avoidance, certain groups of patients are initially diagnosed during the gestational age step into the third trimester. While the presence of right ventricular failure in early gestation is usually trivial, it can be more severe in the late trimester. Current evidence shows no consensus in the management and serious precautions for each stage of the pre-, peri- and post-partum periods of this specific group. Pulmonary hypertension-targeted drugs, mode of delivery, type of anesthesia, and some avoidances should be planned among a multidisciplinary team to enhance maternal and fetal survival opportunities. Sudden circulatory collapse from cardiac decompensation during the peri- and post-partum phases is detrimental, and mechanical support such as extracorporeal membrane oxygenation should be considered for mitigating hemodynamics and extending cardiac recovery time. Our review aims to explain the pathophysiology of pulmonary arterial hypertension and summarize the current evidence for critical management and precautions in each stage of pregnancy.

Associations between hypoxia parameters in obstructive sleep apnea and cognition, cortical thickness, and white matter integrity in middle-aged and older adults.

OBJECTIVE: This study aimed to investigate the association between each parameter of intermittent hypoxia in obstructive sleep apnea (OSA) and the cognitive profile, cortical thickness, and white matter integrity in middle-aged and older adults. METHODOLOGY: Participants were newly diagnosed with moderate or severe OSA from the King Chulalongkorn Memorial Hospital, Bangkok, Thailand. Respiratory parameters from polysomnography were extracted. Each participant was tested on a battery of neuropsychological tests and underwent an MRI scan of the brain. Cortical thickness analysis and diffusion tensor imaging analysis were performed. Participants were classified as having either severe or mild hypoxia based on parameters of hypoxia, i.e., oxygen desaturation index, lowest oxygen saturation, and the percentage of total sleep time spent below 90% oxygen saturation. RESULTS: Of 17 patients with OSA, there were 8 men (47%). Median age was 57 years and median AHI was 60.6. Comparison of cortical thickness between the severe and the mild group of each hypoxic parameter revealed two clusters of cortical thinning at the right inferior frontal gyrus (p-value = 0.008) and right inferior parietal gyrus (p-value = 0.006) in the severe desaturation group and a cluster of cortical thinning at the superior parietal gyrus (p-value = 0.008) in the high oxygen desaturation index group. There was no difference in cognitive function or white matter integrity between groups. CONCLUSIONS: The magnitude of the degree and frequency of desaturations in OSA are associated with a decrease in cortical thickness at the frontal and parietal regions.

MetaSleepLearner: A Pilot Study on Fast Adaptation of Bio-Signals-Based Sleep Stage Classifier to New Individual Subject Using Meta-Learning.

Identifying bio-signals based-sleep stages requires time-consuming and tedious labor of skilled clinicians. Deep learning approaches have been introduced in order to challenge the automatic sleep stage classification conundrum. However, the difficulties can be posed in replacing the clinicians with the automatic system due to the differences in many aspects found in individual bio-signals, causing the inconsistency in the performance of the model on every incoming individual. Thus, we aim to explore the feasibility of using a novel approach, capable of assisting the clinicians and lessening the workload. We propose the transfer learning framework, entitled MetaSleepLearner, based on Model Agnostic Meta-Learning (MAML), in order to transfer the acquired sleep staging knowledge from a large dataset to new individual subjects (source code is available at https://github.com/IoBT-VISTEC/MetaSleepLearner). The framework was demonstrated to require the labelling of only a few sleep epochs by the clinicians and allow the remainder to be handled by the system. Layer-wise Relevance Propagation (LRP) was also applied to understand the learning course of our approach. In all acquired datasets, in comparison to the conventional approach, MetaSleepLearner achieved a range of 5.4% to 17.7% improvement with statistical difference in the mean of both approaches. The illustration of the model interpretation after the adaptation to each subject also confirmed that the performance was directed towards reasonable learning. MetaSleepLearner outperformed the conventional approaches as a result from the fine-tuning using the recordings of both healthy subjects and patients. This is the first work that investigated a non-conventional pre-training method, MAML, resulting in a possibility for human-machine collaboration in sleep stage classification and easing the burden of the clinicians in labelling the sleep stages through only several epochs rather than an entire recording.

Successful multimodality management of severe pulmonary arterial hypertension during pregnancy with VA-ECMO and atrial septostomy using stent.

A 30-year-old Thai woman (gravida 1, para 0) at 33 weeks gestation was referred to our hospital due to acute right ventricular failure. Pulmonary vasodilators were gradually administered before delivery. On the verge of sudden postpartum cardiac circulation collapse, she was resuscitated with veno-arterial extracorporeal membrane oxygenation (VA-ECMO). Abdominal compartment syndrome was developed in the early period of the mechanical support. Knowledge of pathophysiology about pulmonary arterial hypertension during pregnancy was applied. Atrial septostomy was the effective procedure for discontinuing mechanical support (VA-ECMO) corresponding to the suitable timing for maximal effect of pulmonary vasodilators. The patient and her child were safe and discharged in 2 months after the admission.

Obstructive sleep apnea as a risk factor for preeclampsia-eclampsia.

PURPOSE: Preeclampsia-eclampsia remains one of the leading causes of maternal and perinatal morbidity and mortality. Emerging evidence suggests that obstructive sleep apnea (OSA), which has been linked to hypertension in the general population, may play role in hypertensive disorders in pregnancy, including preeclampsia-eclampsia. However, little research has been conducted in Asia (no data in Thailand) on the effects of OSA on preeclampsia-eclampsia. We aimed to examine the association between OSA and preeclampsia-eclampsia among Thai pregnant women. METHODS: We conducted a large prospective cohort study among Thai pregnant women who were in the second trimester of singleton pregnancy. The Berlin Questionnaire was administered to evaluate the risk for OSA. Preeclampsia-eclampsia was diagnosed by standard clinical assessment. Multivariate models were applied in adjustment for confounding factors. RESULTS: Enrolled were 1345 pregnant women. The overall prevalence of high risk for OSA was 10.1% (95% confidence intervals [CIs] 8.5-11.7), and it was significantly associated with pre-pregnancy body mass index and score on the Perceived Stress Scale. An adjusted odds ratio (OR) for preeclampsia-eclampsia in women with high risk for OSA was 2.72 (95% CI 1.33-5.57). CONCLUSIONS: Pregnant women with high risk for OSA are at increased risks for preeclampsia-eclampsia compared to those with low risk for OSA. Our results support a role for screening for OSA by BQ during antenatal care.

Rapid Eye Movement Sleep Behavior Disorder: A Review of the Literature and Update on Current Concepts.

Rapid eye movement (REM) sleep behavior disorder (RBD) is characterized by abnormal behaviors emerging during REM sleep that may cause injury or sleep disruption. The diagnosis requires polysomnography (PSG) demonstrating a loss of normal skeletal muscle atonia during REM sleep. RBD results from dysfunction of the brain stem circuits responsible for maintaining normal REM sleep atonia and suppressing behaviors during REM sleep. The diagnosis of idiopathic RBD (IRBD), that is, RBD without an identifiable cause, is frequently followed years later by the development of a neurodegenerative disorder, most commonly one of the synucleinopathies. As such, RBD is often a step in the progression of a neurodegenerative disorder. In this circumstance, it is a manifestation of neurodegeneration occurring in the brain stem before spreading to adjacent and other CNS regions, resulting in the development of symptoms and signs that permit recognition of a specific neurodegenerative disorder. RBD has been linked with narcolepsy and has been associated with a variety of other disorders. The management of RBD focuses on preventive/safety measures, counseling, monitoring for the development of a neurodegenerative disorder, and pharmacotherapy, which is typically effective but not well understood. The purpose of this article is to review and update our current understanding of the clinical features, epidemiology, demographics, pathophysiology, evaluation, diagnosis, differential diagnosis, causes, associations, and the clinical management of RBD.

Association between respiratory events and nocturnal gastroesophageal reflux events in patients with coexisting obstructive sleep apnea and gastroesophageal reflux disease.

BACKGROUND: Literature has addressed the increased prevalence of gastroesophageal reflux disease (GERD) in obstructive sleep apnea (OSA). Significant improvement of GERD has been found after OSA treatment. However, precise mechanisms underlying this correlation remain unclear. We examined the association between nocturnal gastroesophageal reflux (GER) and sleep events in patients with coexisting OSA and GERD. METHODS: A case-crossover study among 12 patients with coexisting moderate-severe OSA and GERD was conducted. Participants underwent simultaneous polysomnography and esophageal impedance and pH monitoring. GER subtypes (ie, acid reflux, non-acid reflux) were defined as outcomes. Respective control time points were selected in all eligible control periods. Each sleep event was assessed individually. Estimated odds ratios (ORs) and 95% confidence intervals (CIs) were analyzed. A p-value of < 0.05 was considered significant. RESULTS: Patients were determined as moderate to severe OSA (respiratory disturbance index of 42.66 [±22.09]). There were a total of 50 GER episodes, 22 acid reflux and 28 non-acid reflux. Arousals and awakenings were significantly associated with subsequent GER events. The OR for GER following an arousal was 2.31 (95% CI 1.39-3.68; p < 0.001) and following an awakening was 3.71 (95% CI 1.81-7.63; p < 0.001). GER events were significantly less likely to occur after other respiratory events (OR 0.38 [95% CI 0.18-0.82]; p = 0.01). No sleep events followed GER events (p > 0.05). CONCLUSIONS: Both awakening and arousal appear to precipitate any subtype of GER events in patients with coexisting GERD and moderate to severe OSA. However, GER events were significantly less likely to occur after other respiratory events and did not appear to cause sleep-related events.

Obstructive sleep apnea and the risk of preterm delivery.

OBJECTIVE: The aim of this study was to evaluate the risk of obstructive sleep apnea (OSA) to preterm delivery (PTD), using the Berlin Questionnaire (BQ). METHODS: This was a large, prospective cohort study among pregnant Thai women. The BQ was employed for symptom-based OSA screening during the second trimester, and PTD was recorded in 1345 pregnant women. Multivariate models were applied in controlling for potential confounders. RESULTS: The overall prevalence of the high risk of OSA was 10.1 %, and it was significantly associated with pre-pregnancy body mass index and score on the Perceived Stress Scale. An adjusted odds ratio for PTD in women with a high risk of OSA was 2.00 (95 % confidence intervals (CIs) = 1.20, 3.34). Stratified analyses, after adjusting for confounding factors, indicated that a high risk of OSA was associated with an increased risk of spontaneous preterm delivery (odds ratio (OR) = 2.45, 95 % CI = 1.20, 5.02), but not with preterm premature rupture of membranes (OR = 1.61, 95 % CI = 0.61, 4.26), and medically indicated preterm delivery (OR = 1.83, 95 % CI = 0.72, 4.64). CONCLUSION: Pregnant women with a high risk of OSA are at an increased risk of having PTD, compared with pregnant women with a low risk of OSA.

Increased Sleep Disturbances in Thai Children With Attention-Deficit Hyperactivity Disorder Compared With Typically Developing Children.

This study compares sleep disturbances in Thai children aged 5-12 years with attention-deficit hyperactivity disorder (ADHD) and typically developing children using the Children's Sleep Habits Questionnaire (CSHQ)-Thai version. Fifty-five children with ADHD and 110 typically developing children were enrolled. Their parents completed the CSHQ, the ADHD rating scales, and the Strengths and Difficulties Questionnaire (SDQ). Children with ADHD had significantly higher scores in all subscales of the CSHQ compared to controls. Among children with ADHD, children with higher SDQ scores (> 15) appeared to have more sleep disturbances than those with relatively lower SDQ scores. Moreover, fewer sleep-related behavioral problems were observed in the medication treated group, which is particularly new to the field and for some perhaps not unexpected clinically.

Sleep-related cortical arousals in adult subjects with negative polysomnography.

PURPOSE: The arousal index (AI) quantifies cortical arousal relative to total sleep time and is widely used to determine the severity of sleep fragmentation. It usually includes arousals secondary to respiratory events, limb movements, and spontaneous arousals. No systematic studies have been undertaken to determine AI cutoff in subjects with negative polysomnography. METHODS: Three hundred fifty polysomnograms of subjects ≥18 years of age with no sleep disorders (apnea-hypopnea index (AHI) <5, periodic limb movement index (PLMI) <10, no upper airway resistance syndrome) or minimum oxygen saturation > 90 % and no comorbid health problems were reviewed. RESULTS: Basic sleep architecture appears within normal range, except for increased stage N2 and decreased stage N3. AI significantly correlated with age (r = 0.7), sleep efficiency (r =-0.16), sleep latency (r = 0.14), rapid eye movement (REM) latency (r = 0.12), stage N1 (r = 0.15), stage N2 (r = 0.12), stage N3 (r = -0.27), AHI (r = 0.24), PLMI (r = 0.18), and nadir oxygen saturation (r = -0.17) [p < 0.05 for all]. A significant correlation was noted between age and sleep efficiency (r = -0.19), REM latency (r = 0.13), stage N1 (r = 0.16), stage N2 (r = 0.21), stage N3 (r = -0.39), and nadir oxygen saturation (r = -0.16) [p < 0.05 for all]. Multiple linear regression analysis showed that age is only the independent predictor of AI (R (2) = 0.70, p < 0.01). The prediction equation for the arousal index in subject with negative polysomnography is AI = 0.276 × age (year) + 8.018. CONCLUSIONS: Age is the most important independent factor in predicting increasing AI in subjects with negative polysomnography.

Comparison of polysomnographic and clinical presentations and predictors for cardiovascular-related diseases between non-obese and obese obstructive sleep apnea among Asians.

INTRODUCTION: Unlike Caucasians, many Asians with obstructive sleep apnea (OSA) are non-obese but are affected by the disease due to predisposing craniofacial structure. Therefore, non-obese and obese OSA may represent different disease entities. The associated risk factors for developing cardiovascular-related diseases, consequently, may be considered separately for the two types of OSA. METHOD: We reviewed polysomnographic studies performed in adults (aged ≥ 18 years) diagnosed with OSA (respiratory disturbance index [RDI] ≥ 5). We divided the patients into obese (body mass index [BMI] ≥ 25) and non-obese (BMI < 25) groups. We aimed to determine the differences between these two groups in terms of clinical presentations, polysomno-graphic findings, and association with cardiovascular-related diseases including hypertension, diabetes mellitus, coronary artery disease, and/or cerebrovascular disease. RESULTS: Among 194 patients with OSA (RDI ≥ 5), 63.4% were non-obese and 36.6% were obese. Compared with obese OSA patients, non-obese OSA patients were noted to have smaller neck size, less prevalence of hypertension, and less history of frequent nocturia (> 3-4/week), with equal prevalence of excessive daytime sleepiness. Overall, non-obese OSA patients were noted to have milder disease indicated by lower total, supine, and non-supine, NREM RDI and higher mean and nadir oxygen saturations. In the non-obese group, only total obstructive apnea index (OAI) was noted to be a predictor for developing any of the cardiovascular-related diseases after controlling for age, sex, and RDI (odds ratio = 9.7). However, in the obese OSA group, frequent snoring (> 50% of total sleep time), low sleep efficiency (≤ 90%), and low mean oxygen saturation (< 95%) were noted to be significant predictors of cardiovascular-related diseases (odds ratios = 12.3, 4.2, and 5.2, respectively). CONCLUSION: Among Asians, most OSA patients were not obese. Compared to obese OSA patients, non-obese OSA patients were noted to have less prevalence of hypertension and less history of nocturia. They were also noted to have overall milder OSA. Only OAI was noted to be a significant predictor for cardiovascular-related disease in the non-obese OSA group.

Polysomnographic determinants of nocturnal hypercapnia in patients with sleep apnea.

STUDY OBJECTIVES: Identify polysomnographic and demographic factors associated with elevation of nocturnal end-tidal CO2 in patients with obstructive sleep apnea. METHODS: Forty-four adult patients with obstructive sleep apnea were selected such that the maximal nocturnal end-tidal CO2 was below 45 mm Hg in 15 studies, between 45 and 50 mm Hg in 14, and above 50 mm Hg in 15. Measurements included mean event (i.e., apneas or hypopneas) and mean inter-event duration, ratio of mean post- to mean pre-event amplitude, and percentage of total sleep time spent at an end-tidal CO2 < 45, 45-50, and > 50 mm Hg. An integrated nocturnal CO2 was calculated as the sum of the products of average end-tidal CO2 at each time interval by percent of total sleep time spent at the corresponding time interval. RESULTS: The integrated nocturnal CO2 was inversely correlated with mean post-apnea duration, with lesser contributions from mean apnea duration and age (R (2) = 0.56), but did not correlate with the apnea-hypopnea index, or the body mass index. Mean post-event to mean pre-event amplitude correlated with mean post-apnea duration (r = 0.88, p < 0.001). Mean apnea duration did not correlate with mean post-apnea duration. CONCLUSIONS: Nocturnal capnometry reflects pathophysiologic features of sleep apnea, such as the balance of apnea and post-apnea duration, which are not captured by the apnea-hypopnea index. This study expands the indications of capnometry beyond apnea detection and quantification of hypoventilation syndromes.

Severity of obstructive sleep apnea in patients with and without cardiovascular-related diseases.

BACKGROUND: Previous studies have often investigated the association of obstructive sleep apnea (OSA) with cardiovascular morbidity and mortality, but the possibility of reverse causation has not been clearly defined. OBJECTIVE: To examine if the presence of any of the cardiovascular-related diseases, including hypertension, diabetes mellitus, coronary artery disease, and/or cerebrovascular disease, correlates with more severe OSA. METHODS: This was a retrospective study where all patients age ≥ 18 years referred to our sleep laboratory for suspected OSA were included. The data from the full-night baseline and split-night polysomnographic reports were reviewed. Data were then evaluated by logistic regression analysis to compare between 2 groups, the severity of OSA (respiratory disturbance index [RDI] < 15 vs RDI ≥ 15, and RDI < 5 vs RDI ≥ 5), other polysomnographic variables and daytime sleepiness score (Epworth Sleepiness Scale [ESS] score < 10 and ≥ 10). RESULTS: 190 patients were analyzed. The patients with any of the cardiovascular-related diseases were noted to have more severe sleep apnea (RDI ≥ 15), with an adjusted odds ratio of 3.24. Sleep efficiency ≥ 90% and mean oxygen saturation ≥ 95% were observed less commonly in the patients with any of the cardiovascular-related diseases (adjusted odds ratios of 0.45 and 0.36, respectively). There was no statistically significant difference in ESS score. CONCLUSIONS: Patients with any of the cardiovascular-related diseases are at a higher risk of having moderate to severe OSA without significant increase in daytime sleepiness. Therefore, we suggest that patients with any of the cardiovascular-related diseases should be screened for OSA, even if they are asymptomatic.

Clinical and polysomnographic data of positional sleep apnea and its predictors.

INTRODUCTION: In Asian population, facial structure may contribute to the primary pathophysiology of obstructive sleep apnea (OSA). We hypothesized that sleep position may have more effect on OSA in Asians compared to the Western population. If this hypothesis is accurate, positional therapy will have a major impact on treatment of OSA among Asians. PATIENTS/METHODS: We reviewed 263 polysomnographic studies from our laboratory from January 1, 2010 to June 30, 2010. Criteria for positional and non-positional OSA were (1) supine respiratory disturbance index (RDI)/non-supine RDI ≥2 and total RDI ≥5 and (2) supine RDI/non-supine RDI <2 and total RDI ≥5, respectively. We aimed to determine the difference in baseline characteristics, polysomnographic findings, and predictors for positional OSA. RESULTS: We found 144 patients diagnosed with OSA (RDI ≥5), and 96 patients met the criteria for positional OSA (67%), in which in almost half of these patients (47%), RDI was normalized (RDI < 5) in non-supine position. Snoring frequency were significantly lower among positional OSA and OSA was less severe indicated by lower RDI and arousal index, higher mean and nadir oxygen saturation, and higher %NREM3. We also found that low snoring frequency (less than 20% of total sleep time) was a significant predictor for positional OSA (odd ratio of 3.27; p = 0.011), contrarily to low mean oxygen saturation (<95%) which was found to be a negative predictor (odd ratio of 0.31; p = 0.009). Among OSA patients, low RDI (<15) was a significant predictor for normalization of RDI in non-supine position (odd ratio of 8.77; p = < 0.001), contrarily to low mean oxygen saturation (<95%) which was also found to be a negative predictor (odd ratio of 0.13; p = 0.001). CONCLUSION: Positional OSA is very prevalent and noted in almost 70% of our patients. Low snoring frequency was noted to be a positive predictor for positional OSA, contrarily to low mean oxygen saturation which was found to be a negative predictor. These findings are encouraging that positional therapy can be very beneficial as the treatment modality for OSA among Asians.

Prevalence and correlates of alpha-delta sleep in major depressive disorders.

Objective. Major depressive disorder is associated with sleep disturbances. An electroencephalographic pattern of alpha wave intrusion in delta wave sleep (alpha-delta sleep) is observed in some subjects with major depressive disorder. The treatment-resistant symptoms in major depressive disorder, nonrestorative sleep and fatigue, are associated with alpha-delta sleep. The objective of this study is to identify the prevalence and clinical correlates of alpha-delta sleep in major depressive disorder.Design. Retrospective studySetting. Sleep Disorders Center, Cleveland Clinic, Cleveland, OhioParticipants. Polysomnograms were conducted on 150 subjects 18 years of age or older (75 with and 75 without major depressive disorder) were reviewed.Measurements. The percent of delta waves with alpha intrusion was collected and analyzed.Results. Subjects with major depressive disorder compared to nondepressed subjects had a higher sleep efficiency (83.0±9.6; 78.1±8.2%), shorter rapid eye movement latency (85.0±44.5; 189.9±25.6 min), less slow wave sleep (8.3±3.0; 13.5±6.2%), and greater rapid eye movement (24.7±7.0; 19.2±8.2%), and all of these findings were statistically significant. Patients with major depressive disorder had higher alpha-delta sleep (23.4±14.2%; 2.3±6.7%, p<0.01). Patients with major depressive disorder were categorized into high and low alpha-delta sleep based on percentage of alpha-delta sleep present in slow wave sleep (alpha-delta sleep was present ≥15% or ≤15% of slow wave sleep, respectively). Patients with major depressive disorder with high alpha-delta sleep were at 3.15 greater odds (1.22-8.14; p=0.018) to have excessive daytime sleepiness.Conclusion. Patients with major depressive disorder have a higher prevalence of alpha-delta sleep. Alpha-delta sleep is associated with daytime sleepiness in patients with major depressive disorder. Study limitations include the retrospective nature of the project and the fact that the principle investigator, who scored and interpreted alpha intrusion, was not blind to group membership.

Prevalence of gastroesophageal reflux in Thai asthmatic patients.

BACKGROUND: Asthma is a chronic inflammatory disorder of airways and associated with airway hyperresponsiveness and reversible bronchoconstriction. Gastroesophageal reflux disease (GERD) is a disorder caused by the reflux of gastric content up into the esophagus. It has been proposed that GERD is one of the exacerbating factors in the patients with poor controlled asthma. OBJECTIVE: Determine the prevalence of GERD in asthmatic patients and the association between GERD and the level of asthma control in Thailand. MATERIAL AND METHOD: A cross-sectional descriptive study was conducted in 56 asthmatic patients at the King Chulalongkorn Memorial Hospital. They were performed twenty-four-hour esophageal pH monitoring. RESULTS: The prevalence of GERD in Thai asthmatic patients was 37.50%. Fifteen of 21 patients (71.43%) with GERD experienced reflux symptoms. The sensitivity specificity, positive predictive value and negative predictive value of reflux symptoms for diagnosis GERD were 71.43%, 77.14%, 65.22% and 81.82%, respectively. The prevalence of GERD was higher in uncontrolled asthmatic patients than partly controlled and controlled subjects. Among uncontrolled asthma, the prevalence of GERD was higher than those without GERD (57.17% and 25.72%, respectively, p = 0.028). Asthma Control Test (ACT) score of less than twenty (poor controlled asthma) was higher in the asthmatic patients with GERD than those without GERD (80.95% and 48.57%, respectively, p = 0.024). CONCLUSION: The authors concluded that the prevalence of GERD in Thai asthmatic patients was 37.50%. There was significant association between GERD and the level of asthma control.

Does CPAP treatment in mild obstructive sleep apnea affect blood pressure?

OBJECTIVES: Obstructive sleep apnea (OSA) is associated with significant cardiovascular (CV) morbidity. Continuous positive airway pressure (CPAP) is the standard treatment for moderate to severe OSA, resulting in a reduction in CV morbidity. No studies have compared CV outcomes between CPAP and no CPAP in mild OSA (5>or=AHI<15). METHODS: Retrospective cohort study of subjects (age>or=18) with mild OSA diagnosed between 2004 and 2006. Subjects with a history of hypertension, angina, stroke and smoking were excluded. Subjects were stratified into two groups: CPAP (n=93) or no CPAP (n=162). The mean blood pressures (MBP) were compared 2 years after the diagnosis of OSA was established. RESULTS: Unmatched for covariates (age, sex, BMI, neck circumference, AHI, arousal index and family h/o CV disorders), subjects with mild OSA on CPAP had a 1.97 point reduction, and no CPAP resulted in a 9.61 point elevation (p<0.0001) in MBP. With propensity score matching for covariates, the mean difference in MBP was -1.97 (95% CI: -14.03, -9.92; p<0.0001) with a sensitivity analysis of 2.646. CONCLUSION: This study shows an elevation of the MBP in mild OSA patients who were not treated with CPAP. CPAP treatment in mild OSA patients decreased the MBP over a 2-year period.