Prevalence and Population-Attributable Risk for Chronic Airflow Obstruction in a Large Multinational Study.

Rationale: The Global Burden of Disease program identified smoking and ambient and household air pollution as the main drivers of death and disability from chronic obstructive pulmonary disease (COPD). Objectives: To estimate the attributable risk of chronic airflow obstruction (CAO), a quantifiable characteristic of COPD, due to several risk factors. Methods: The Burden of Obstructive Lung Disease study is a cross-sectional study of adults, aged ≥40, in a globally distributed sample of 41 urban and rural sites. Based on data from 28,459 participants, we estimated the prevalence of CAO, defined as a postbronchodilator FEV1-to-FVC ratio less than the lower limit of normal, and the relative risks associated with different risk factors. Local relative risks were estimated using a Bayesian hierarchical model borrowing information from across sites. From these relative risks and the prevalence of risk factors, we estimated local population attributable risks. Measurements and Main Results: The mean prevalence of CAO was 11.2% in men and 8.6% in women. The mean population attributable risk for smoking was 5.1% in men and 2.2% in women. The next most influential risk factors were poor education levels, working in a dusty job for ≥10 years, low body mass index, and a history of tuberculosis. The risk of CAO attributable to the different risk factors varied across sites. Conclusions: Although smoking remains the most important risk factor for CAO, in some areas, poor education, low body mass index, and passive smoking are of greater importance. Dusty occupations and tuberculosis are important risk factors at some sites.

Chronic airflow obstruction and ambient particulate air pollution.

Smoking is the most well-established cause of chronic airflow obstruction (CAO) but particulate air pollution and poverty have also been implicated. We regressed sex-specific prevalence of CAO from 41 Burden of Obstructive Lung Disease study sites against smoking prevalence from the same study, the gross national income per capita and the local annual mean level of ambient particulate matter (PM2.5) using negative binomial regression. The prevalence of CAO was not independently associated with PM2.5 but was strongly associated with smoking and was also associated with poverty. Strengthening tobacco control and improved understanding of the link between CAO and poverty should be prioritised.

Altered cardiac repolarisation in highlanders with high-altitude pulmonary hypertension during wakefulness and sleep.

High-altitude pulmonary hypertension (HAPH) is an altitude-related illness associated with hypoxaemia that may promote sympathetic excitation and prolongation of the QT interval. The present case-control study tests whether QT intervals, markers of malignant cardiac arrhythmias, are prolonged in highlanders with HAPH (HAPH+) compared to healthy highlanders (HH) and healthy lowlanders (LL). The mean pulmonary artery pressure (mPAP) was measured by echocardiography in 18 HAPH+ (mPAP, 34 mmHg) and 18 HH (mPAP, 23 mmHg) at 3,250 m, and 18 LL (mPAP, 18 mmHg) at 760 m, Kyrgyzstan (p < .05 all mPAP comparisons). Groups were matched for age, sex and body mass index. Electrocardiography and pulse oximetry were continuously recorded during nocturnal polysomnography. The heart rate-adjusted QT interval, QTc, was averaged over consecutive 1-min periods. Overall, a total of 26,855 averaged 1-min beat-by-beat periods were semi-automatically analysed. In HAPH+, maximum nocturnal QTc was longer during sleep (median 456 ms) than wakefulness (432 ms, p < .05) and exceeded corresponding values in HH (437 and 419 ms) and LL (430 and 406 ms), p < .05, respectively. The duration of night-time QTc >440 ms was longer in HAPH+ (median 144 min) than HH and LL (46 and 14 min, p < .05, respectively). HAPH+ had higher night-time heart rate (median 78 beats/min) than HH and LL (66 and 65 beats/min, p < .05, respectively), lower mean nocturnal oxygen saturation than LL (88% versus 95%, p < .05) and more cyclic oxygen desaturations (median 24/hr) than HH and LL (13 and 3/hr, p < .05, respectively). In conclusion, HAPH was associated with higher night-time heart rate, hypoxaemia and longer QTc versus HH and LL, and may represent a substrate for increased risk of malignant cardiac arrhythmias.

Cardiac function and pulmonary hypertension in Central Asian highlanders at 3250†m.

THE QUESTION ADDRESSED BY THE STUDY: Chronic exposure to hypoxia increases pulmonary artery pressure (PAP) in highlanders, but the criteria for diagnosis of high-altitude pulmonary hypertension (HAPH) are debated. We assessed cardiac function and PAP in highlanders at 3250 m and explored HAPH prevalence using different definitions. PATIENTS AND METHODS: Central Asian highlanders free of overt cardiorespiratory disease, permanently living at 2500-3500 m compared to age-matched lowlanders living <800 m. Participants underwent echocardiography close to their altitude of residence (at 3250 m versus 760 m). RESULTS: 173 participants (97 highlanders, 76 lowlanders), mean±sd age 49±9 years (49% females) completed the study. Results in lowlanders versus highlanders were systolic PAP (23±5 versus 30±10 mmHg), right ventricular fractional area change (42±6% versus 39±8%), tricuspid annular plane systolic excursion (2.1±0.3 versus 2.0±0.3 cm), right atrial volume index (20±6 versus 23±8 mL·m-2), left ventricular ejection fraction (62±4% versus 57±5%) and stroke volume (64±10 versus 57±11 mL); all between-group comparisons p<0.05. Depending on criteria, HAPH prevalence varied between 6% and 35%. THE ANSWER TO THE QUESTION: Chronic exposure to hypoxia in highlanders is associated with higher PAP and slight alterations in right and left heart function compared to lowlanders. The prevalence of HAPH in this large highlander cohort varies between 6% according to expert consensus definition of chronic high-altitude disease to 35% according to the most recent definition of pulmonary hypertension proposed for lowlanders.

Implementing lung health interventions in low- and middle-income countries: a FRESH AIR systematic review and meta-synthesis.

The vast majority of patients with chronic respiratory disease live in low- and middle-income countries (LMICs). Paradoxically, relevant interventions often fail to be effective particularly in these settings, as LMICs lack solid evidence on how to implement interventions successfully. Therefore, we aimed to identify factors critical to the implementation of lung health interventions in LMICs, and weigh their level of evidence.This systematic review followed Cochrane methodology and Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) reporting standards. We searched eight databases without date or language restrictions in July 2019, and included all relevant original, peer-reviewed articles. Two researchers independently selected articles, critically appraised them (using Critical Appraisal Skills Programme (CASP)/Meta Quality Appraisal Tool (MetaQAT)), extracted data, coded factors (following the Consolidated Framework for Implementation Research (CFIR)), and assigned levels of confidence in the factors (via Grading of Recommendations Assessment, Development and Evaluation-Confidence in the Evidence from Reviews of Qualitative research (GRADE-CERQual)). We meta-synthesised levels of evidence of the factors based on their frequency and the assigned level of confidence (PROSPERO:CRD42018088687).We included 37 articles out of 9111 screened. Studies were performed across the globe in a broad range of settings. Factors identified with a high level of evidence were: 1) "Understanding needs of local users"; 2) ensuring "Compatibility" of interventions with local contexts (cultures, infrastructures); 3) identifying influential stakeholders and applying "Engagement" strategies; 4) ensuring adequate "Access to knowledge and information"; and 5) addressing "Resource availability". All implementation factors and their level of evidence were synthesised in an implementation tool.To conclude, this study identified implementation factors for lung health interventions in LMICs, weighed their level of evidence, and integrated the results into an implementation tool for practice. Policymakers, non-governmental organisations, practitioners, and researchers may use this FRESH AIR (Free Respiratory Evaluation and Smoke-exposure reduction by primary Health cAre Integrated gRoups) Implementation tool to develop evidence-based implementation strategies for related interventions. This could increase interventions' implementation success, thereby optimising the use of already-scarce resources and improving health outcomes.

No time for change? Impact of contextual factors on the effect of training primary care healthcare workers in Kyrgyzstan and Vietnam on how to manage asthma in children - A FRESH AIR implementation study.

BACKGROUND: Training is a common and cost-effective way of trying to improve quality of care in low- and middle-income countries but studies of contextual factors for the successful translation of increased knowledge into clinical change are lacking, especially in primary care. The purpose of this study was to assess the impact of contextual factors on the effect of training rural healthcare workers in Kyrgyzstan and Vietnam on their knowledge and clinical performance in managing pediatric patients with respiratory symptoms. METHODS: Primary care health workers in Kyrgyzstan and Vietnam underwent a one-day training session on asthma in children under five. The effect of training was measured on knowledge and clinical performance using a validated questionnaire, and by direct clinical observations. RESULTS: Eighty-one healthcare workers participated in the training. Their knowledge increased by 1.1 Cohen's d (CI: 0.7 to 1.4) in Kyrgyzstan where baseline performance was lower and 1.5 Cohen's d (CI: 0.5 to 2.5) in Vietnam. Consultations were performed by different types of health care workers in Kyrgyzstan and there was a 79.1% (CI 73.9 to 84.3%) increase in consultations where at least one core symptom of respiratory illness was asked. Only medical doctors participated in Vietnam, where the increase was 25.0% (CI 15.1 to 34.9%). Clinical examination improved significantly after training in Kyrgyzstan. In Vietnam, the number of actions performed generally declined. The most pronounced difference in contextual factors was consultation time, which was median 15 min in Kyrgyzstan and 2 min in Vietnam. DISCUSSION AND CONCLUSION: The effects on knowledge of training primary care health workers in lower middle-income countries in diagnosis and management of asthma in children under five only translated into changes in clinical performance where consultation time allowed for changes to clinical practice, emphasizing the importance of considering contextual factors in order to succeed in behavioral change after training.

High COPD prevalence at high altitude: does household air pollution play a role?

Studies comparing chronic obstructive pulmonary disease (COPD) prevalence across altitudes report conflicting results. However, household air pollution (HAP), a major COPD risk factor, was mostly not accounted for in previous analyses and never objectively measured. We aimed to compare the prevalence of COPD and its risk factors between low-resource highlands and lowlands, with a particular focus on objectively measured HAP.We conducted a population-based, observational study in a highland (∼2050 m above sea level) and a lowland (∼750 m above sea level) setting in rural Kyrgyzstan. We performed spirometry in randomly selected households, measured indoor particulate matter with an aerodynamic diameter <2.5 µm (PM2.5) and administered a questionnaire on other COPD risk factors. Descriptive statistics and multivariable logistic regressions were used for analyses.We included 392 participants: 199 highlanders and 193 lowlanders. COPD was more prevalent among highlanders (36.7% versus 10.4%; p<0.001). Their average PM2.5 exposure was also higher (290.0 versus 72.0 µg·m-3; p<0.001). In addition to high PM2.5 exposure (OR 3.174, 95% CI 1.061-9.493), the altitude setting (OR 3.406, 95% CI 1.483-7.825), pack-years of smoking (OR 1.037, 95% CI 1.005-1.070) and age (OR 1.058, 95% CI 1.037-1.079) also contributed to a higher COPD prevalence among highlanders.COPD prevalence and HAP were highest in the highlands, and were independently associated. Preventive interventions seem warranted in these low-resource, highland settings. With this study being one of the first spirometry-based prevalence studies in Central Asia, generalisability needs to be assessed.

The socioeconomic burden of chronic lung disease in low-resource settings across the globe - an observational FRESH AIR study.

BACKGROUND: Low-resource settings are disproportionally burdened by chronic lung disease due to early childhood disadvantages and indoor/outdoor air pollution. However, data on the socioeconomic impact of respiratory diseases in these settings are largely lacking. Therefore, we aimed to estimate the chronic lung disease-related socioeconomic burden in diverse low-resource settings across the globe. To inform governmental and health policy, we focused on work productivity and activity impairment and its modifiable clinical and environmental risk factors. METHODS: We performed a cross-sectional, observational FRESH AIR study in Uganda, Vietnam, Kyrgyzstan, and Greece. We assessed the chronic lung disease-related socioeconomic burden using validated questionnaires among spirometry-diagnosed COPD and/or asthma patients (total N = 1040). Predictors for a higher burden were studied using multivariable linear regression models including demographics (e.g. age, gender), health parameters (breathlessness, comorbidities), and risk factors for chronic lung disease (smoking, solid fuel use). We applied identical models per country, which we subsequently meta-analyzed. RESULTS: Employed patients reported a median [IQR] overall work impairment due to chronic lung disease of 30% [1.8-51.7] and decreased productivity (presenteeism) of 20.0% [0.0-40.0]. Remarkably, work time missed (absenteeism) was 0.0% [0.0-16.7]. The total population reported 40.0% [20.0-60.0] impairment in daily activities. Breathlessness severity (MRC-scale) (B = 8.92, 95%CI = 7.47-10.36), smoking (B = 5.97, 95%CI = 1.73-10.22), and solid fuel use (B = 3.94, 95%CI = 0.56-7.31) were potentially modifiable risk factors for impairment. CONCLUSIONS: In low-resource settings, chronic lung disease-related absenteeism is relatively low compared to the substantial presenteeism and activity impairment. Possibly, given the lack of social security systems, relatively few people take days off work at the expense of decreased productivity. Breathlessness (MRC-score), smoking, and solid fuel use are potentially modifiable predictors for higher impairment. Results warrant increased awareness, preventive actions and clinical management of lung diseases in low-resource settings from health policymakers and healthcare workers.

Asthma rehabilitation at high vs. low altitude: randomized parallel-group trial.

BACKGROUND: To investigate the effect of asthma rehabilitation at high altitude (3100 m, HA) compared to low altitude (760 m, LA). METHODS: For this randomized parallel-group trial insufficiently controlled asthmatics (Asthma Control Questionnaire (ACQ) > 0.75) were randomly assigned to 3-week in-hospital rehabilitation comprising education, physical-&breathing-exercises at LA or HA. Co-primary outcomes assessed at 760 m were between group changes in peak expiratory flow (PEF)-variability, and ACQ) from baseline to end-rehabilitation and 3 months thereafter. RESULTS: 50 asthmatics were randomized [median (quartiles) LA: ACQ 2.7(1.7;3.2), PEF-variability 19%(14;33); HA: ACQ 2.0(1.6;3.0), PEF-variability 17%(12;32)]. The LA-group improved PEF-variability by median(95%CI) -7%(- 14 to 0, p = 0.033), ACQ - 1.4(- 2.2 to - 0.9, p < 0.001), and after 3 months by - 3%(- 18 to 2, p = 0.103) and - 0.9(- 1.3 to - 0.3, p = 0.002). The HA-group improved PEF-variability by - 10%(- 21 to - 3, p = 0.004), ACQ - 1.1(- 1.3 to - 0.7, p < 0.001), and after 3 months by - 9%(- 10 to - 3, p = 0.003) and - 0.2(- 0.9 to 0.4, p = 0.177). The additive effect of HA vs. LA directly after the rehabilitation on PEF-variability was - 6%(- 14 to 2), on ACQ 0.3(- 0.4 to 1.1) and after 3 months - 5%(- 14 to 5) respectively 0.4(- 0.4 to 1.1), all p = NS. CONCLUSION: Asthma rehabilitation is highly effective in improving asthma control in terms of PEF-variability and symptoms, both at LA and HA similarly. TRIAL REGISTRATION: Clinicaltrials.gov: NCT02741583, Registered April 18, 2016.

Association between sleep apnoea and pulmonary hypertension in Kyrgyz highlanders.

This case-control study evaluates a possible association between high altitude pulmonary hypertension (HAPH) and sleep apnoea in people living at high altitude.Ninety highlanders living at altitudes >2500 m without excessive erythrocytosis and with normal spirometry were studied at 3250 m (Aksay, Kyrgyzstan); 34 healthy lowlanders living below 800 m were studied at 760 m (Bishkek, Kyrgyzstan). Echocardiography, polysomnography and other outcomes were assessed. Thirty-six highlanders with elevated mean pulmonary artery pressure (mPAP) >30 mmHg (31-42 mmHg by echocardiography) were designated as HAPH+. Their data were compared to that of 54 healthy highlanders (HH, mPAP 13-28 mmHg) and 34 healthy lowlanders (LL, mPAP 8-24 mmHg).The HAPH+ group (median age 52 years (interquartile range 47-59) had a higher apnoea-hypopnoea index (AHI) of 33.8 events·h-1 (26.9-54.6) and spent a greater percentage of the night-time with an oxygen saturation <90% (T<90; 78% (61-89)) than the HH group (median age 39 years (32-48), AHI 9.0 events·h-1 (3.6-16), T<90 33% (10-69)) and the LL group (median age 40 years (30-47), AHI 4.3 events·h-1 (1.4-12.6), T<90 0% (0-0)); p<0.007 for AHI and T<90, respectively, in HAPH+ versus others. In highlanders, multivariable regression analysis confirmed an independent association between mPAP and both AHI and T<90, when controlled for age, gender and body mass index.Pulmonary hypertension in highlanders is associated with sleep apnoea and hypoxaemia even when adjusted for age, gender and body mass index, suggesting pathophysiologic interactions between pulmonary haemodynamics and sleep apnoea.

The Feasibility of C-Reactive Protein Point-of-Care Testing to Reduce Overuse of Antibiotics in Children with Acute Respiratory Tract Infections in Rural Kyrgyzstan: A Pilot Study.

Background: In Kyrgyzstan, the morbidity prevalence of and morbidity from acute respiratory tract infections (ARTI) in children is high. Local healthcare workers (HCW) often prescribe antibiotics that are not indicative due to a mix of professional and societal factors. It is suggested to precede with a decision on antibiotics by a point-of-care test (POCT) on the appropriateness of the treatment, eg, a measurement of C-reactive protein (CRP). CRP-guided antibiotic stewardship in children with ARTI has not previously been studied in Central Asia. Purpose: This pilot study was conducted to examine the feasibility of the methods and procedures to be used in the upcoming randomised controlled COORDINATE clinical trial (NCT05195866) and in daily clinical practice in primary care. Patients and methods: HCWs from three selected rural healthcare facilities were trained in the CRP POCT and in interpretation of results. Children aged 6 months to 12 years attending the primary healthcare facilities with respiratory symptoms were randomly assigned to CRP-guided management or standard care, guided by clinical findings only. Children were followed up for 14 days by scheduled telephone calls to caregivers. Results: Eighty-one children participated in this pilot study. The CRP POCT and the trial procedures were acceptable to the target group as well as to the HCWs. Children from both groups recovered equally well, with an observed significant lower use of antibiotics in the CRP group. HCWs generally adhered to the CRP guidelines, and only once was an antibiotic prescribed despite low CRP results. No safety concerns were observed. Four parents provided wrong phone numbers impeding follow-up. We will collect all mobile phone numbers in the household for the main trial. Conclusion: The pilot provided satisfactory results, suggesting that the COORDINATE trial of CRP POCT is effective, feasible with minor adjustments and without apparent safety concerns for the participants.

Sleep medicine in the Kyrgyz Republic: past, present, and future.

STUDY OBJECTIVES: As in many other Low and Middle Income Countries (LMICs) around the world, sleep disorders in the Kyrgyz Republic remain mostly undiagnosed and untreated. This article aims to describe the current state of practice of sleep medicine in the Kyrgyz Republic from the perspective of local and international health care workers who are active in the field and to propose a strategy to challenge the status quo. METHODS: We performed a policy analysis and interviewed local doctors working in the field. RESULTS: We identified 3 major barriers to the practice of sleep medicine and namely education and training, financial constraints and infrastructure and equipment. We then propose a multistep strategy to improve the current situation based on 3 pillars: knowledge sharing, implementation research activities and policy changes. CONCLUSIONS: Despite being at its early days and facing major challenges, sleep health in the Kyrgyz Republic is being recognized as a priority by health care workers in the field and now requires attention at local and government level. Furthermore, north-south academic partnerships represent an effective tool for knowledge sharing and should be further incentivised. CITATION: Cirri L, Bolotbek uulu A, Shakiev N, et al. Sleep medicine in the Kyrgyz Republic: past, present, and future. J Clin Sleep Med. 2024;20(7):1213-1216.

The FRESHAIR4Life study: Global implementation research on non-communicable disease prevention targeting adolescents' exposure to tobacco and air pollution in disadvantaged populations.

The FRESHAIR4Life study aims to reduce the non-communicable disease (NCD) burden by implementing preventive interventions targeting adolescents' exposure to tobacco use and air pollution (AP) worldwide. This paper presents the FRESHAIR4Life methodology and initial rapid review results. The rapid review, using various databases and PubMed, aimed to guide decision-making on risk factor focus, target areas, and populations. It showed variable NCD mortality rates related to tobacco use and AP across the participating countries, with tobacco as the main risk factor in the Kyrgyz Republic, Greece, and Romania, and AP prevailing in Pakistan and Uganda. Adolescent exposure levels, sources, and correlates varied. The study will continue with an in-depth situational analysis to guide the selection, adaptation, and integration of evidence-based interventions into the FRESHAIR4Life prevention package. This package will be implemented, evaluated, assessed for cost-effectiveness, and iteratively refined. The research places a strong emphasis on co-creation, capacity building, and comprehensive communication and dissemination.

SARS-CoV-2 Transmission during High-Altitude Field Studies.

Grimm, Mirjam, Lucie Ziegler, Annina Seglias, Maamed Mademilov, Kamila Magdieva, Gulzada Mirzalieva, Aijan Taalaibekova, Simone Suter, Simon R. Schneider, Fiona Zoller, Vera Bissig, Lukas Reinhard, Meret Bauer, Julian Müller, Tanja L. Ulrich, Arcangelo F. Carta, Patrick R. Bader, Konstantinos Bitos, Aurelia E. Reiser, Benoit Champigneulle, Damira Ashyralieva, Philipp M. Scheiwiller, Silvia Ulrich, Talant M. Sooronbaev, Michael Furian, and Konrad E. Bloch. SARS-CoV-2 Transmission during High-Altitude Field Studies. High Alt Med Biol. 00:00-00, 2024. Background: Throughout the severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) pandemic, virus transmission during clinical research was of concern. Therefore, during high-altitude field studies performed in 2021, we took specific COVID-19 precautions and investigated the occurrence of SARS-CoV-2 infection. Methods: From May to September 2021, we performed studies in patients with chronic obstructive pulmonary disease (COPD) and in healthy school-age children in Kyrgyzstan in high-altitude facilities at 3,100 m and 3,250 m and at 760 m. The various implemented COVID-19 safety measures included systematic SARS-CoV-2 rapid antigen testing (RAT). Main outcomes were SARS-CoV-2-RAT-positive rate among participants and staff at initial presentation (prevalence) and SARS-CoV-2-RAT-positive conversion during and within 10 days after studies (incidence). Results: Among 338 participants and staff, SARS-CoV-2-RAT-positive prevalence was 15 (4.4%). During mean ± SD duration of individual study participation of 3.1 ± 1.0 day and within 10 days, RAT-positive conversion occurred in 1/237(0.4%) participants. Among staff working in studies for 31.5 ± 29.3 days, SARS-CoV-2-RAT-positive conversion was 11/101(10.9%). In all 338 individuals involved in the studies over the course of 15.6 weeks, the median SARS-CoV-2-RAT-positive incidence was 0.00%/week (quartiles 0.00; 0.64). Over the same period, the median background incidence among the total Kyrgyz population of 6,636 million was 0.06%/week (0.03; 0.11), p = 0.013 (Wilcoxon rank sum test). Conclusions: Taking precautions by implementing specific safety measures, SARS-CoV-2 transmission during clinical studies was very rare, and the SARS-CoV-2 incidence among participants and staff was lower than that in the general population during the same period. The results are reassuring and may help in decision-making on the conduct of clinical research in similar settings.

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.

Counseling Patients with Chronic Obstructive Pulmonary Disease Traveling to High Altitude.

Bloch, Konrad E., Talant M. Sooronbaev, Silvia Ulrich, Mona Lichtblau, and Michael Furian. Clinician's corner: counseling patients with chronic obstructive pulmonary disease traveling to high altitude. High Alt Med Biol. 24:158-166, 2023.-Mountain travel is increasingly popular also among patients with chronic obstructive pulmonary disease (COPD), a highly prevalent condition often associated with cardiovascular and systemic manifestations. Recent studies have shown that nonhypercapnic and only mildly hypoxemic lowlanders with moderate to severe airflow obstruction owing to COPD experience dyspnea, exercise limitation, and sleep disturbances when traveling up to 3,100 m. Altitude-related adverse health effects (ARAHE) in patients with COPD include severe hypoxemia, which may be asymptomatic but expose patients to the risk of excessive systemic and pulmonary hypertension, cardiac arrhythmia, and even myocardial or cerebral ischemia. In addition, hypobaric hypoxia may impair postural control, psycho-motor, and cognitive performance in patients with COPD during altitude sojourns. Randomized, placebo-controlled trials have shown that preventive treatment with oxygen at night or with acetazolamide reduces the risk of ARAHE in patients with COPD while preventive dexamethasone treatment improves oxygenation and altitude-induced excessive sleep apnea, and lowers systemic and pulmonary artery pressure. This clinical review provides suggestions for pretravel assessment and preparations and measures during travel that may reduce the risk of ARAHE and contribute to pleasant mountain journeys of patients with COPD.

Effect of Acetazolamide on Postural Control in Patients with COPD Travelling to 3100 m Randomized Trial.

Patients with chronic obstructive pulmonary disease (COPD) may be susceptible to impairments in postural control (PC) when exposed to hypoxia at high altitude. This randomized, placebo-controlled, double-blind, parallel-design trial evaluated the effect of preventive acetazolamide treatment on PC in lowlanders with COPD traveling to 3100 m. 127 lowlanders (85 men, 42 women) with moderate to severe COPD, aged 57 ± 8 y, living below 800 m, were randomized to treatment with acetazolamide 375 mg/d starting 24 h before ascent from 760 m to 3100 m and during a 2-day sojourn in a clinic at 3100 m. PC was evaluated at both altitudes with a balance platform on which patients were standing during five tests of 30 s each. The primary outcome was the center of pressure path length (COPL). In the placebo group, COPL significantly increased from (mean ± SD) 28.8 ± 9.7 cm at 760 m to 30.0 ± 10.0 cm at 3100 m (p = 0.002). In the acetazolamide group, COPL at 760 m and 3100 m were similar with 27.6 ± 9.6 cm and 28.4 ± 9.7 cm (p = 0.069). The mean between-groups difference (acetazolamide-placebo) in altitude-induced change of COPL was -0.54 cm (95%CI -1.66 to 0.58, p = 0.289). Multivariable regression analysis confirmed an increase in COPL of 0.98 cm (0.39 to 1.58, p = 0.001) with ascent from 760 to 3100 m, but no significant effect of acetazolamide (0.66 cm, 95%CI -0.25 to 1.57, p = 0.156) when adjusting for several confounders. In lowlanders with moderate to severe COPD, an ascent to high altitude was associated with impaired postural control and this was not prevented by acetazolamide.

C reactive protein-guided prescription of antibiotics for children under 12 years with respiratory symptoms in Kyrgyzstan: protocol for a randomised controlled clinical trial with 14 days follow-up.

INTRODUCTION: While lower respiratory tract infections are the main cause of death for children under 5 globally, only a small proportion of children with respiratory tract infections need antibiotics. Overuse of antibiotics globally is leading to increasing rates of antibiotic resistance. In Kyrgyzstan, healthcare workers regularly prescribe antibiotics when clinical uncertainty is present to err on the side of caution. Targeting antibiotic use with biomarkers of inflammation such as C reactive protein (CRP) testing at the point-of-care test (POCT) has been shown to reduce antibiotic use in general, but only few studies have been done in children and no studies exist from Central Asia. This study aims to assess whether the use of a CRP POCT can safely decrease prescription of antibiotics for children with acute respiratory symptoms in primary level healthcare centres in Kyrgyzstan. METHODS AND ANALYSIS: Multicentre, open-label, individually randomised, controlled clinical trial with 14 days follow-up (follow-up by phone on days 3, 7 and 14) in rural lowland Chui and highland Naryn regions of Kyrgyzstan. The population are children aged 6 months to 12 years attending the primary level healthcare centres during normal business hours with acute respiratory symptoms. CRP POCT equipment will be supplied to healthcare centres, along with a short training session in CRP use, including the interpretation of results to support the clinical evaluation of the child with acute respiratory infection. The primary outcomes are the proportion of patients prescribed an antibiotic within 14 days of index consultation (superiority analysis) and days to recovery (non-inferiority analysis). Secondary outcomes are antibiotics prescribed at index consultation, reconsultations, hospital admission and vital status within 14 days. Analysis of the first primary outcome, antibiotic use, will be intention to treat using a logistic regression model. Analysis of the second primary outcome, days to recovery, will be per protocol using a linear regression model and a non-inferiority margin of 1 day. ETHICS AND DISSEMINATION: The study was approved on 18 June 2021 by the Ethics Committee (ref: no. 1) of the National Centre of Maternity and Childhood Care, Bishkek, Kyrgyzstan. The results of the study regardless of the conclusion will be presented at international conferences and published in peer-reviewed scientific medical journals along with policy briefs and technical reports. TRIAL REGISTRATION NUMBER: NCT05195866.

Effect of altitude and acetazolamide on sleep and nocturnal breathing in healthy lowlanders 40 y of age or older. Data from a randomized trial.

STUDY OBJECTIVES: To assess altitude-induced sleep and nocturnal breathing disturbances in healthy lowlanders 40 y of age or older and the effects of preventive acetazolamide treatment. METHODS: Clinical examinations and polysomnography were performed at 760 m and in the first night after ascent to 3100 m in a subsample of participants of a larger trial evaluating altitude illness. Participants were randomized 1:1 to treatment with acetazolamide (375 mg/day) or placebo, starting 24 h before and while staying at 3100 m. The main outcomes were indices of sleep structure, oxygenation, and apnea/hypopnea index (AHI). RESULTS: Per protocol analysis included 86 participants (mean ± SE 53 ± 7 y old, 66% female). In 43 individuals randomized to placebo, mean nocturnal pulse oximetry (SpO2) was 94.0 ± 0.4% at 760 m and 86.7 ± 0.4% at 3100 m, with mean change (95%CI) -7.3% (-8.0 to -6.5); oxygen desaturation index (ODI) was 5.0 ± 2.3 at 760 m and 29.2 ± 2.3 at 3100 m, change 24.2/h (18.8 to 24.5); AHI was 11.3 ± 2.4/h at 760 m and 23.5 ± 2.4/h at 3100 m, change 12.2/h (7.3 to 17.0). In 43 individuals randomized to acetazolamide, altitude-induced changes were mitigated. Mean differences (Δ, 95%CI) in altitude-induced changes were: ΔSpO2 2.3% (1.3 to 3.4), ΔODI -15.0/h (-22.6 to -7.4), ΔAHI -11.4/h (-18.3 to -4.6). Total sleep time, sleep efficiency, and N3-sleep fraction decreased with an ascent to 3100 m under placebo by 40 min (17 to 60), 5% (2 to 8), and 6% (2 to 11), respectively. Acetazolamide did not significantly change these outcomes. CONCLUSIONS: During a night at 3100 m, healthy lowlanders aged 40 y or older revealed hypoxemia, sleep apnea, and disturbed sleep. Preventive acetazolamide treatment improved oxygenation and nocturnal breathing but had no effect on sleep duration and structure. TRIAL REGISTRATION: The trial is registered at Clinical Trials, https://clinicaltrials.gov, NCT03561675.