Changes in all-cause and cause-specific excess mortality before and after the Omicron outbreak of COVID-19 in Hong Kong.

Background: While coronavirus 2019 (COVID-19) deaths were generally underestimated in many countries, Hong Kong may show a different trend of excess mortality due to stringent measures, especially for deaths related to respiratory diseases. Nevertheless, the Omicron outbreak in Hong Kong evolved into a territory-wide transmission, similar to other settings such as Singapore, South Korea, and recently, mainland China. We hypothesized that the excess mortality would differ substantially before and after the Omicron outbreak. Methods: We conducted a time-series analysis of daily deaths stratified by age, reported causes, and epidemic wave. We determined the excess mortality from the difference between observed and expected mortality from 23 January 2020 to 1 June 2022 by fitting mortality data from 2013 to 2019. Results: During the early phase of the pandemic, the estimated excess mortality was -19.92 (95% confidence interval (CI) = -29.09, -10.75) and -115.57 (95% CI = -161.34, -69.79) per 100 000 population overall and for the elderly, respectively. However, the overall excess mortality rate was 234.08 (95% CI = 224.66, 243.50) per 100 000 population overall and as high as 928.09 (95% CI = 885.14, 971.04) per 100 000 population for the elderly during the Omicron epidemic. We generally observed negative excess mortality rates of non-COVID-19 respiratory diseases before and after the Omicron outbreak. In contrast, increases in excess mortality were generally reported in non-respiratory diseases after the Omicron outbreak. Conclusions: Our results highlighted the averted mortality before 2022 among the elderly and patients with non-COVID-19 respiratory diseases, due to indirect benefits from stringent non-pharmaceutical interventions. The high excess mortality during the Omicron epidemic demonstrated a significant impact from the surge of COVID-19 infections in a SARS-CoV-2 infection-naive population, particularly evident in the elderly group.

Determining meteorologically-favorable zones for seasonal influenza activity in Hong Kong.

Investigations of simple and accurate meteorology classification systems for influenza epidemics, particularly in subtropical regions, are limited. To assist in preparing for potential upsurges in the demand on healthcare facilities during influenza seasons, our study aims to develop a set of meteorologically-favorable zones for epidemics of influenza A and B, defined as the intervals of meteorological variables with prediction performance optimized. We collected weekly detection rates of laboratory-confirmed influenza cases from four local major hospitals in Hong Kong between 2004 and 2019. Meteorological and air quality records for hospitals were collected from their closest monitoring stations. We employed classification and regression trees to identify zones that optimize the prediction performance of meteorological data in influenza epidemics, defined as a weekly rate > 50th percentile over a year. According to the results, a combination of temperature > 25.1℃ and relative humidity > 79% was favorable to epidemics in hot seasons, whereas either temperature < 16.4℃ or a combination of < 20.4℃ and relative humidity > 76% was favorable to epidemics in cold seasons. The area under the receiver operating characteristic curve (AUC) in model training achieved 0.80 (95% confidence interval [CI], 0.76-0.83) and was kept at 0.71 (95%CI, 0.65-0.77) in validation. The meteorologically-favorable zones for predicting influenza A or A and B epidemics together were similar, but the AUC for predicting influenza B epidemics was comparatively lower. In conclusion, we established meteorologically-favorable zones for influenza A and B epidemics with a satisfactory prediction performance, even though the influenza seasonality in this subtropical setting was weak and type-specific.

Feasibility of long-term home noninvasive ventilation program in a general pediatric unit: 21 years' experience in Hong Kong.

BACKGROUND: Long-term home noninvasive ventilation (NIV) is increasingly employed in children with sleep-disordered breathing and chronic respiratory failure. While studies suggest its successful implementation in tertiary care centers, little is known about the situation in a general care setting. Hence, we aim to evaluate the clinical profiles of these children in a general pediatric unit over the past two decades. METHODS: Data collected retrospectively on patients younger than 18 years old receiving long-term home NIV from January 1, 1997 to December 31, 2017 in a Hong Kong regional general pediatric unit were reviewed. RESULTS: The number of children on home NIV increased more than 10-fold over the past two decades. In total, 114 children were commenced on NIV during the 21-year period. Upper airway obstruction was the most common cause (77%), followed by neuromuscular diseases (16%), pulmonary disorders (4%), and abnormal ventilatory control (3%). Continuous positive airway pressure was the most common NIV type (59%). To date, 46% of the children remained in our NIV program, while 18% discontinued NIV support. NIV adherence increased significantly with follow-up (median of 78.6% and 82.5% at baseline and last follow-up, respectively). Sixty-five percent of the children used NIV for at least 4 h on 70% of the days monitored. Higher body mass index was associated with lower adherence. CONCLUSION: Pediatric home NIV is feasible in the general care setting with good outcomes and adherence. As the demand for NIV service grows, input from local hospitals will be of increasing importance and should be considered upon healthcare planning.

Short-term association among meteorological variation, outdoor air pollution and acute bronchiolitis in children in a subtropical setting.

OBJECTIVES: To examine the association among acute bronchiolitis-related hospitalisation in children, meteorological variation and outdoor air pollution. METHODS: We obtained the daily counts of acute bronchiolitis-related admission of children≤2 years old from all public hospitals, meteorological data and outdoor air pollutants' concentrations between 1 January 2008 and 31 December 2017 in Hong Kong. We used quasi-Poisson generalised additive models together with distributed lag non-linear models to estimate the associations of interest adjusted for confounders. RESULTS: A total of 29 688 admissions were included in the analysis. Increased adjusted relative risk (ARR) of acute bronchiolitis-related hospitalisation was associated with high temperature (ambient temperature and apparent temperature) and was marginally associated with high vapour pressure, a proxy for absolute humidity. High concentration of NO2 was associated with elevated risk of acute bronchiolitis admission; the risk of bronchiolitis hospitalisation increased statistically significantly with cumulative NO2 exposure over the range 66.2-119.6 µg/m3. For PM10, the significant effect observed at high concentrations appears to be immediate but not long lasting. For SO2, ARR increased as the concentration approached the 75th percentile and then decreased though the association was insignificant. CONCLUSIONS: Acute bronchiolitis-related hospitalisation among children was associated with temperature and exposure to NO2 and PM10 at different lag times, suggesting a need to adopt sustainable clean air policies, especially to target pollutants produced by motor vehicles, to protect young children's health.

A 21-year retrospective analysis of environmental impacts on paediatric acute gastroenteritis in an affluent setting.

BACKGROUND: Extreme weather events happen more frequently along with global warming and they constitute a challenge for public health preparedness. For example, many investigations showed heavy rainfall was associated with an increased risk of acute gastroenteritis. In this study, we examined the associations between different meteorological factors and paediatric acute gastroenteritis in an affluent setting in China controlling for pollutant effects. METHODS: Aggregated total weekly number of intestinal infection-related hospital admissions, and meteorological and air pollution data during 1998-2018 in Hong Kong were collected and analysed by a combination of quasi-Poisson generalized additive model and distributed lag nonlinear model. Study population was restricted to children under 5 years of age at the time of admission. RESULTS: While heavy rainfall did not exhibit a statistically significant association with the risk of paediatric admission due to intestinal infections, low temperature and humidity extremes (both relative humidity and vapour pressure) did. Compared with the temperature at which the lowest risk was detected (i.e. 22.5 °C), the risk was 6.4% higher (95% confidence interval: 0.0% to 13.0% at 15.1 °C (i.e. the 5th percentile)). We also found the risk of paediatric admission was statistically significantly associated with an increase in the number of extreme cold days in a week over the study period. CONCLUSION: Cold condition may have greater impact on disease transmission through increased stability and infectivity of enteric viruses in affluent settings like Hong Kong and thus resulted in an increased risk for paediatric acute gastroenteritis. On the contrary, an insignificant impact from heavy rainfall and high temperature may indicate a minor effect on disease transmission through bacterial growth in contaminated food and water. With the identified impacts of weather factors, extreme weather events are likely to distort the prevalence and seasonal pattern of diarrhoeal diseases in the future.

Use of heated humidified high flow nasal cannula for obstructive sleep apnea in infants.

OBJECTIVE: Heated humidified high flow nasal cannula (HHHFNC) has gained popularity in the treatment of children with respiratory distress and bronchiolitis in the past decade. Its efficacy as a mode of non-invasive respiratory support has been demonstrated in both adults and children. However, reports on its use in the treatment of obstructive sleep apnea (OSA) in infants are limited. We aimed to evaluate the efficacy of HHHFNC therapy as treatment in infants with OSA. METHODS: A retrospective analysis of OSA infants who had undergone polysomnographic titration between 2015 and 2017 was undertaken. Data about the age, gender, AHI, co-morbid conditions and flow used for each patient were retrieved. RESULTS: Ten infants were included in this study (median age 34 weeks; IQR 27-38 weeks). The median optimal HHHFNC flow rate was 8.0 L/min (IQR 6.7-8.0 L/min). HHHFNC significantly reduced median obstructive apnea-hypopnea index (OAHI) from 9.1 (IQR 5.1-19.3) to 0.9 (IQR 0-1.6; P = 0.005) events/h; median obstructive apnea index (OAI) from 5.8 (IQR 1.1-13.4) to 0 (IQR 0-0.9; P = 0.021) events/h; median obstructive hypopnea index (OHI) from 4.1 (IQR 0.9-6.8) to 0.1 (0-0.9; P = 0.017) events/h; and median oxygen saturation (SpO2) nadir increased from 88% (IQR 83-94%) to 94% (IQR 93-96%; P = 0.040). CONCLUSION: HHHFNC significantly reduced respiratory events and improved oxygenation in infants with OSA.

Management of Recurrent Preschool, Doctor-Diagnosed Wheeze.

Preschool wheeze occurs in half of the children before they reach 6 y of age and recurrence is also common. Recurrent preschool wheeze is classified as either typical or atypical. For typical recurrent preschool wheeze, the diagnoses are either asthma or bronchiolitis/bronchitis. Responsiveness to a properly administered bronchodilator confirms asthma, atopic or otherwise. All atypical preschool wheeze should be referred to pediatric respirologist for assessment. Lung function test by impulse oscillometry (IOS) before and after bronchodilator is helpful to confirm airway hyperresponsiveness, an essential feature of asthma. Assessment of atopy is important by either skin prick test or serum IgE level. Treatment of acute wheeze includes standard supportive care, bronchodilator for those diagnosed with asthma and hypertonic saline for those diagnosed as having acute bronchiolitis. Other treatments included nebulized adrenaline for acute bronchiolitis and systemic steroids for asthma. For those with significant respiratory distress, continuous positive airway pressure (CPAP) or heated humidified high flow should be considered. Daily or intermittent inhaled corticosteroid or intermittent montelukast would reduce asthma exacerbation rate. A significant proportion of preschool wheeze persists till school age. An early diagnosis of asthma would be important to allow early optimal management.

A randomized placebo-controlled trial of traditional Chinese medicine as an add-on therapy to oral montelukast in the treatment of mild persistent asthma in children.

OBJECTIVES: Traditional Chinese medicine are commonly used for treatment of asthma. However, there are only very limited data about its efficacy in children. Therefore, we aimed to determine the efficacy of augmented Yu Ping Feng San (aYPFS) as an add-on to oral montelukast compared with montelukast alone for treatment of mild persistent asthma in children. DESIGN: A single centre, placebo-controlled, double-blinded, randomized control trial was carried out. Participants with age 6-18 years who had mild persistent asthma were randomized according to random number list to receive either aYPFS plus montelukast for 24 weeks or placebo plus montelukast for 24 weeks. Primary outcome measure was lung function parameters. Secondary outcome measures were Asthma Control Test™ (ACT™) and Paediatric Allergic Disease Quality of Life Questionnaire (PADQLQ) scores, symptom-free days, short-acting ß2-agonist use, use of rescue oral corticosteroids, days of hospitalization for asthma and number of emergency consultation with GPs or AED department. RESULTS: Twenty-eight participants were randomized to aYPFS group and twenty-nine to placebo group. There was no significant difference in baseline characteristics. There was significant improvement in ACT™ score in aYPFS group (up to 6.9% change from baseline) (p=0.016) but not in the control group. There were no significant differences between groups in other primary and secondary outcome parameters. Dropout because of adverse effects is comparable in both groups. CONCLUSION: Traditional Chinese medicine aYPFS as an add-on to montelukast improved symptoms of asthma control. Further studies with larger sample size are needed to evaluate its efficacy and safety in childhood asthma.

Ambulatory blood pressure before and after adenotonsillectomy in children with obstructive sleep apnea.

INTRODUCTION: Hypertension is found to be associated with obstructive sleep apnea (OSA) in both children and adults. But data on the effect of blood pressure after adenotonsillectomy (AT) for children with OSA are limited and controversial. OBJECTIVE: To assess the impact of AT on different parameters of 24-h ambulatory blood pressure monitoring in children with OSA. METHODS: We retrospectively reviewed records of OSA children who had undergone AT and a repeated sleep polysomnography after AT from 2001 to 2008. RESULTS: Forty-four children were identified and included in the analysis. The mean apnea-hypopnea index (AHI) dropped from 14.14+/-15.9 to 3.3+/-7.1. (p<0.001). Twenty (45%) were cured of OSA. After AT, the diastolic BP load decreased significantly. Six out of eight (75%) hypertensive children became normotensive after surgery. For the pre-AT hypertensive group, both systolic and diastolic blood pressure decreased significantly during sleep after AT. However, eight children who were normotensive before AT became hypertensive after AT. These 10 post-AT hypertensive patients were more likely to have post-AT AHI>1 than the post-AT normotensive group, although the difference did not reach statistical significance. CONCLUSION: In the current cohort of OSA children, 44% were cured of OSA and a significant decrease in overall diastolic blood pressure load in 24-h ambulatory blood pressure was achieved after adenotonsillectomy for children with OSA. But hypertension may persist or even occur in those previously normotensive children despite the improvement in AHI. Persistence of OSA may be a risk factor and further study is required. Cure of OSA should not be assumed after AT and follow-up PSG should be performed together with 24-h ambulatory blood pressure monitoring. In light of the current findings, long term study of the blood pressure is warranted for children with OSA.

Application of videotape in the screening of obstructive sleep apnea in children.

OBJECTIVE: To determine if watching a videotape that shows features of obstructive sleep apnea (OSA) will improve the accuracy of a verbally administered questionnaire in the prediction of OSA in pediatric snorers. PATIENTS AND METHODS: In a prospective single-blinded, randomized, controlled study at a pediatric clinic for sleep-disordered breathing, we studied children aged 0-18 years, who had been referred to a sleep laboratory for overnight polysomnography (PSG), and their parents from November 1999 to November 2000. The parents were randomized to answer a standard verbally administered panel of three questions (SQ) or a verbally administered panel of questions assisted by videotape (VQ). RESULTS: The parents of 52 and 56 pediatric snorers were assigned to answer SQ and VQ, respectively. The areas under the receiver operating characteristic [ROC] curves (AUCs) for screening of OSA in patients were similar at 0.709 (95% confidence interval (CI)=0.561-0.851) for SQ and 0.714 (95% CI=0.571-0.858) for VQ. The two questionnaires had a reasonable negative predictive value to rule out the presence of OSA (VQ=0.816 and 95% CI=0.726-0.885, SQ=0.828, 95% CI=0.714-0.913). CONCLUSION: The addition of a videotape showing important features of OSA achieved no better accuracy than a standard questionnaire.

The correlation among obesity, apnea-hypopnea index, and tonsil size in children.

BACKGROUND: The correlation between obesity and severity of obstructive sleep apnea (OSA) is well established in adults, but data are inconsistent in children. We hypothesized that there is a significant correlation between the degree of obesity and the severity of OSA in children. METHODS: We retrospectively reviewed records of weight, height, history, and polysomnography of all 1- to 15- year-old children referred to our sleep laboratory. Children with known anomalies and repeated polysomnography were excluded from this study. Obesity was defined as body mass index z score (BMI Z score) > 1.96. The correlation between BMI Z score and apnea-hypopnea index (AHI) was assessed. Possible confounding factors, ie, age, gender, and tonsil size, were adjusted by multiple linear regression. RESULTS: Four hundred eighty-two children were included in this study. Obese children had a significantly higher AHI (median, 1.5; interquartile range [IQR], 0.2 to 7.0) than the AHI of nonobese children (median, 0.7; IQR, 0.0 to 2.5). BMI Z score was significantly correlated with log-transformed AHI (Ln[AHI]) [r = 0.156, p = 0.003]. BMI Z score and tonsil size were still correlated with Ln(AHI) even after adjusted for other confounding factors (p = 0.001). CONCLUSION: Degree of obesity as measured by BMI Z score and tonsil size are significantly related to severity of OSA as reflected by the AHI, although the correlation is mild.

Prevalence of sleep problems in Hong Kong primary school children: a community-based telephone survey.

STUDY OBJECTIVES: To estimate the prevalence of snoring, witnessed sleep apnea, teeth grinding, primary and secondary nocturnal enuresis, and sleep duration in Hong Kong primary school children. DESIGN: Cross-sectional telephone questionnaire survey in a community. PARTICIPANTS: A total of 3,047 6- to 12-year-old apparently healthy children. INTERVENTION: Those who agreed to the study were contacted by telephone. Survey questions were asked about the symptoms of the different sleep disorders, and the frequency of each positive symptom was noted for the preceding 1 week. OUTCOME MEASURES: Prevalence and risk factors of sleep disorders in Hong Kong primary school children. RESULTS: The prevalence of the following sleep symptoms was listed as follows: habitual snoring (10.9%), witnessed sleep apnea (1.5%), nocturnal enuresis (5.1%), and sleep teeth grinding (20.5%). Significant risk factors for habitual snoring included witnessed sleep apnea, mouth breathing during sleep, snoring in first-degree relatives, headache on rising, male gender, allergic rhinitis, and sleep teeth grinding. Significant risk factors for witnessed sleep apnea included habitual snoring, allergic rhinitis, tiredness on rising, and excessive daytime sleepiness. Poor academic results were associated with present of witnessed sleep apnea and absence of sleep teeth grinding. None of the sleep problem was associated with poor conduct results. The mean sleep duration was 8.79 h (SD 0.96). CONCLUSIONS: This study provides epidemiologic data of sleep-disordered breathing, enuresis, sleep teeth grinding, and duration of sleep in Chinese primary school children in Hong Kong.