Ten-year territory-wide trends in the utilisation and clinical outcomes of extracorporeal membrane oxygenation in Hong Kong

INTRODUCTION

The utilisation of extracorporeal membrane oxygenation (ECMO) has been rapidly increasing in Hong Kong. This study examined 10-year trends in the utilisation and clinical outcomes of ECMO in Hong Kong.

METHODS

We retrospectively reviewed the records of all adult patients receiving ECMO who were admitted to the intensive care units (ICUs) of public hospitals in Hong Kong between 2010 and 2019. Temporal trends across years were assessed using the Mann-Kendall test. Observed hospital mortality was compared with the Acute Physiology and Chronic Health Evaluation (APACHE) IV-predicted mortality.

RESULTS

The annual number of patients receiving ECMO increased from 18 to 171 over 10 years. In total, 911 patients received ECMO during the study period: 297 (32.6%) received veno-arterial ECMO, 450 (49.4%) received veno-venous ECMO, and 164 (18.0%) received extracorporeal cardiopulmonary resuscitation. The annual number of patients aged ≥65 years increased from 0 to 47 (27.5%) [P for trend=0.001]. The median (interquartile range) Charlson Comorbidity Index increased from 1 (0-1) to 2 (1-3) [P for trend<0.001] while the median (interquartile range) APACHE IV score increased from 90 (57-112) to 105 (77-137) [P for trend=0.003]. The overall standardised mortality ratio comparing hospital mortality with APACHE IV-predicted mortality was 1.11 (95% confidence interval=1.01-1.22). Hospital and ICU length of stay both significantly decreased (P for trend=0.011 and <0.001, respectively).

CONCLUSION

As ECMO utilisation increased in Hong Kong, patients put on ECMO were older, more critically ill, and had more co-morbidities. It is important to combine service expansion with adequate resource allocation and training to maintain quality of care.

Re-examine the transfusion transmitted risk of SARS-CoV-2 virus during a major COVID-19 outbreak in 2022

INTRODUCTION

Although no case of COVID-19 transmission through transfusion has been reported, blood transfusion service (BTS) continues to implement pre-donation and post-donation measures to minimise the risk. In year 2022, when local healthcare system was badly impacted by a major outbreak, it opened an opportunity to re-examine the viraemia risk in these asymptomatic donors.

MATERIALS AND METHODS

Records were retrieved from blood donors who reported COVID-19 after donation and follow-up was also made for recipients who received their blood. Blood samples at donation were tested for SARS-CoV-2 viraemia by single-tube nested real-time RT-PCR assay designed to detect most SARS-CoV-2 variants including the prevailing delta and omicron variants.

RESULTS

From 1 January to 15 August 2022, the city with 7.4 M inhabitants recorded 1 187 844 COVID-19 positive cases and 125 936 successful blood donations were received. 781 donors reported to the BTS after donation with 701 being COVID-19 related (including close contact and symptoms respiratory tract infection). 525 COVID-19 were positive at the time of call back or follow-up. Of the 701 donations, they were processed into 1480 components with 1073 discarded upon donors' call back. For remaining 407 components, no recipient was found to have adverse event or COVID-19 positive. 510 samples from the above 525 COVID-19 positive donors were available and all tested negative for SARS-CoV-2 RNA.

DISCUSSION

With the negative SARS-CoV-2 RNA in blood donation samples and follow up data in transfusion recipients, the risk of transfusion transmitted COVID-19 appears negligible. However, current measures remains important in securing blood safety with ongoing surveillance of their effectiveness.

A prospective study on serum citrate levels and clinical correlations in patients receiving regional citrate anticoagulation

Background

Current ways to diagnose citrate accumulation (CA) in patients receiving regional citrate anticoagulation (RCA) continuous renal replacement therapy (CRRT) are confounded by various clinical factors. Serum citrate measurement emerges as a more direct way to diagnose CA, but its clinical utility and optimal cut-off values remain undefined. This study examined serum citrate kinetics and its diagnostic performance for CA in patients receiving RCA CRRT.

Methods

A multicentre prospective study was carried out in two tertiary referral centre intensive care units in Hong Kong with serum citrate levels measured at baseline and 2, 6, 12, 24, 36, 48 and 72 h after initiation of RCA CRRT and their relationships with the development of CA.

Results

Among the 133 patients analysed, 18 patients (13.5%) developed CA. The serum citrate levels at baseline and 2, 6 and 12 h after initiation of RCA CRRT in patients who had CA were significantly higher than the non-CA group (P < .001 for all). The CA group also had higher serum citrate levels than the non-CA group {median 0.93 mmol/L [interquartile range (IQR) 0.81-1.16) versus 0.37 mmol/L (IQR 0.26-0.57), P < .001}. Using a cut-off of 0.85 mmol/L, the serum citrate level had a sensitivity of 0.77 and a specificity 0.96 for the diagnosis of CA [area under the receiver operating characteristics curve (AUROC) 0.90, P < .001]. The 2-h and 6-h serum citrate levels had good discriminatory abilities for predicting subsequent development of CA (AUROC 0.86 and 0.83 for 2-h and 6-h citrate levels using cut-off values of 0.34 and 0.63 mmol/L, respectively; P < .001).

Conclusion

Serum citrate levels were significantly higher in patients with CA compared with patients without CA. Serum citrate levels showed good performance in diagnosing and predicting the development of CA.

COVID-19 Pandemic: Consensus guidelines for preferred practices in an aesthetic clinic

Strict infection control measures in response to the current COVID‐19 pandemic are expected to remain for an extended period. In aesthetic clinics, most procedures are provided on one to one basis by the physician or therapist. In such a scenario, guidelines detailing the infection control measures for aesthetic clinics are of particular importance. An online meeting of an international group of experts in the field of aesthetic medicine, with experience in administration of an aesthetic clinic, was convened. The meeting aimed to provide a set of consensus guidelines to protect clinic staff and patients from SARS‐CoV‐2 infection. Consensus guidelines for “preferred practices” were provided for scheduling of patients, patient evaluation and triaging, and for safety precautions about the different procedures. Procedures were categorized into low‐risk, moderate risk, and high‐risk based on the likelihood of transmission of SARS‐CoV‐2 virus from the patient to the treating physician or therapist. While not intended to be complete or exhaustive, these guidelines provide sound infection control measures for aesthetic practices. Since guidelines regarding safety measures and use of PPEs may vary from country to country, the local guidelines should also be followed to prevent COVID‐19 infection in aesthetic clinics.

Population-based cohort study of variation in the use of emergency cholecystectomy for benign gallbladder diseases

Background

The aims of this prospective population-based cohort study were to identify the patient and hospital characteristics associated with emergency cholecystectomy, and the influences of these in determining variations between hospitals.

Methods

Data were collected for consecutive patients undergoing cholecystectomy in acute UK and Irish hospitals between 1 March and 1 May 2014. Potential explanatory variables influencing the performance of emergency cholecystectomy were analysed by means of multilevel, multivariable logistic regression modelling using a two-level hierarchical structure with patients (level 1) nested within hospitals (level 2).

Results

Data were collected on 4744 cholecystectomies from 165 hospitals. Increasing age, lower ASA fitness grade, biliary colic, the need for further imaging (magnetic retrograde cholangiopancreatography), endoscopic interventions (endoscopic retrograde cholangiopancreatography) and admission to a non-biliary centre significantly reduced the likelihood of an emergency cholecystectomy being performed. The multilevel model was used to calculate the probability of receiving an emergency cholecystectomy for a woman aged 40 years or over with an ASA grade of I or II and a BMI of at least 25·0 kg/m2, who presented with acute cholecystitis with an ultrasound scan showing a thick-walled gallbladder and a normal common bile duct. The mean predicted probability of receiving an emergency cholecystectomy was 0·52 (95 per cent c.i. 0·45 to 0·57). The predicted probabilities ranged from 0·02 to 0·95 across the 165 hospitals, demonstrating significant variation between hospitals.

Conclusion

Patients with similar characteristics presenting to different hospitals with acute gallbladder pathology do not receive comparable care.

Telerehabilitation — a new model for community-based stroke rehabilitation

Community resources for stroke clients are underdeveloped in Hong Kong and stroke survivors often face difficulties in community reintegration. We have examined the feasibility of using videoconferencing for community-based stroke rehabilitation. The sample comprised 21 stroke patients living at home. All the subjects participated in an eight-week intervention programme at a community centre for seniors. The intervention, which comprised educational talks, exercise and psychosocial support, was conducted by a physiotherapist via a videoconference link. The Berg Balance Scale (BBS), State Self-Esteem Scale (SSES), Medical Outcomes Study 36-item Short Form (SF-36) and a stroke knowledge test were administered at the start and end of the programme. In addition, at the start of the study the Geriatric Depression Scale 15-item Short Form, the Elderly Mobility Scale and the Lawton Instrumental Activities of Daily Living Scale were used to assess subjects' baseline status, and a focus group was also held at the end of the programme to gather qualitative findings. Nineteen subjects completed the eight-week intervention. The baseline functional status was high, although 52% had symptoms of depression. After the intervention, there were significant improvements in BBS, SSES and knowledge test scores and scores on all subscales of the SF-36. All the subjects accepted the use of videoconferencing for delivery of the intervention. The pilot study demonstrated the feasibility, efficacy and high level of acceptance of telerehabilitation for community-dwelling stroke clients.

Smoking and mortality in a prospective cohort study of elderly Chinese in Hong Kong

BACKGROUND AND AIMS

Large cohort studies on smoking and mortality in elderly people are scarce, and few studies examined smokers aged 85+ years separately. We estimated the risks of all-cause and cause-specific mortality due to smoking in an elderly Chinese cohort in Hong Kong.

DESIGN

A population-based prospective cohort of 65,510 Chinese enrolled from 1998 to 2001 and followed until May 2012.

SETTING

All 18 Elderly Health Service centres in Hong Kong, China.

PARTICIPANTS

Elderly people aged 65+ years.

MEASUREMENTS

Self-reported smoking status was assessed at baseline interview and categorized as never, former and current smokers.

FINDINGS

Compared with never smokers, after adjustment for sex, age, education, social security assistance, housing type, monthly expenditure, alcohol use, depressive symptoms and health status, the hazard ratio (HR) for current smokers was 1.89 [95% confidence interval (CI) = 1.81-1.98] for all participants aged 65+ years at baseline, corresponding to an attributable fraction (AF) of about 50%, which is based on AF = (HR-1)/HR. As the effect of smoking varied with age (P for age interaction <0.001), subgroup analysis by age group showed that the adjusted HR for current smokers aged 65-84 years was 1.93 (95% CI = 1.84-2.03), and for 85+ years was 1.29 (95% CI = 1.05-1.58). All the risk estimates did not vary by sex (P for sex interaction ranged 0.74-0.89).

CONCLUSIONS

In Hong Kong, the risk of death from smoking appears to be the same for Chinese women as it is for men. Half of all deaths in Chinese smokers aged 65 years and older and a quarter of all deaths in Chinese smokers aged 85 years and older are caused by smoking-attributable diseases.

Cohort Profile: Hong Kong Department of Health Elderly Health Service Cohort

The Department of Health Elderly Health Service Cohort in Hong Kong was set up to promote understanding of ageing in a global context, to exploit the role of Hong Kong as a sentinel for populations currently experiencing very rapid economic development, to provide a developed non-Western 'social laboratory' where empirically derived hypotheses can be tested and to leverage the different patterns of common chronic diseases between East and West to generate novel hypotheses about their determinants. The initial cohort enrolled from July 1998 to the end of December 2001 includes 66 820 people aged 65 years or older, forming about 9% of the population of this age. A comprehensive health assessment was made at enrollment and then repeated regularly on an ongoing basis. The health assessment included a comprehensive assessment of lifestyle, social circumstances, physical health and mental health, including an assessment of cognition and depressive symptoms. Health services use and deaths have been obtained by record linkage and confirmed, where necessary, by telephone interview. Currently, the data are not publicly available; we would welcome collaborations and research proposals.

Core stability exercise is as effective as task-oriented motor training in improving motor proficiency in children with developmental coordination disorder: a randomized controlled pilot study

Objective:

To compare the effectiveness of a core stability program with a task-oriented motor training program in improving motor proficiency in children with developmental coordination disorder (DCD).

Design:

Randomized controlled pilot trial.

Setting:

Outpatient unit in a hospital.

Participants:

Twenty-two children diagnosed with DCD aged 6-9 years were randomly allocated to the core stability program or the task-oriented motor program.

Intervention:

Both groups underwent their respective face-to-face training session once per week for eight consecutive weeks. They were also instructed to carry out home exercises on a daily basis during the intervention period.

Main measures:

Short Form of the Bruininks-Oseretsky Test of Motor Proficiency (Second Edition) and Sensory Organization Test at pre- and post-intervention.

Results:

Intention-to-treat analysis revealed no significant between-group difference in the change of motor proficiency standard score ( P=0.717), and composite equilibrium score derived from the Sensory Organization Test ( P=0.100). Further analysis showed significant improvement in motor proficiency in both the core stability (mean change (SD)=6.3(5.4); p=0.008) and task-oriented training groups (mean change(SD)=5.1(4.0); P=0.007). The composite equilibrium score was significantly increased in the task-oriented training group (mean change (SD)=6.0(5.5); P=0.009), but not in the core stability group (mean change(SD) =0.0(9.6); P=0.812). In the task-oriented training group, compliance with the home program was positively correlated with change in motor proficiency (ρ=0.680, P=0.030) and composite equilibrium score (ρ=0.638, P=0.047).

Conclusion:

The core stability exercise program is as effective as task-oriented training in improving motor proficiency among children with DCD.

Long term ketamine and ketamine plus alcohol toxicity - what can we learn from animal models?

This review addressed the adverse effects of the frequently-used recreational drug, ketamine through using mice and monkey models. Our laboratory has documented initially that ketamine can induce the formation of hyperphosphorlated tau (hypertau), which is a hallmark of Alzheimer's disease (AD), in the cerebral cortex of both mice and monkeys as well as apoptosis in neurons in these species. Besides the cerebral cortex, other centers in the central nervous system (CNS) and peripheral nervous system (PNS) are also influenced by ketamine. Cerebellum was found to be down-regulated in both mice and humans after long-term of ketamine administration and it was caused by the apoptosis of Purkinje cells. Deleterious effects in other organs reported in long-term ketamine users include of kidney dysfunction leading to proteinuria, fibrosis of the urinary bladder and reduction in size of the urinary bladder leading to frequent urination, increase of liver fibrosis and cardiac problems such as premature ventricular beats. Moreover, ketamine is usually co-administrated with other chemicals such as caffeine or alcohol. It has been reported increased harmful effects when ketamine was used in combination with the above substances. Mechanisms of damages of ketamine might be due to 1) up-regulation of NMDA receptors leading to overestimation of glutamatergic system or 2) the metabolite of ketamine which was a hydroquinone exerted toxicity.

Effects of built environment on walking among Hong Kong older adults

1. Reliable and valid interviewer-administered questionnaires were developed to investigate associations of perceived neighbourhood attributes of Hong Kong older adults with their walking for transportation and recreation. 2. Access to and availability of different types of services and destinations, provision of facilities for resting/sitting in the neighbourhood, and easy access to/from residential buildings may help maintain an active lifestyle by facilitating walking for transport in the neighbourhood. 3. Access to services, indoor places for walking, environmental aesthetics, low traffic, and absence of physical barriers may promote recreational walking..

Development of a wearable system integrated with novel biomedical sensors for ubiquitous healthcare

The world's ageing population has led to an urgent need for long-term and patient-centered healthcare solutions. Hence, there is a growing need for wearable systems for physiologic monitoring. While various biosignals are monitored with traditional approaches, it is worthwhile to investigate alternative sensing techniques in order to improve accessibility and understanding of patients' conditions. This paper presents our laboratory's development of such a wearable system, which makes use of unconventional techniques for physiologic monitoring. With its integrated textile electrocardiogram (ECG) electrodes, intelligent finger-ring photoplethysmogram (PPG) sensor, miniaturized optical fiber-based temperature sensor, eye dynamics monitor, global positioning system (GPS) module, and wireless capability, it demonstrates a feasible solution for ubiquitous healthcare.

DL-3-n-Butylphthalide, an anti-oxidant agent, prevents neurological deficits and cerebral injury following stroke per functional analysis, magnetic resonance imaging and histological assessment

DL-3-n-Butylphthalide (NBP) is a synthetic compound based on L-3-n-Butylphthalide which was isolated from seeds of Apium graveolens. The present study aims at evaluating the outcome of NBP given prior to and after the onset of ischemic stroke in spontaneously hypertensive rats (SHR) and normotensive Wistar Kyoto rats (WKY). Stroke was induced by the middle cerebral artery occlusion (MCAO) in SHR and WKY. For pre-treatment, NBP was administered to SHR and WKY daily for two months prior to MCAO. For post-treatment, NBP was given daily for seven consecutive days after MCAO. Seven days post-surgery, rats were tested for the presence of neurological deficits. Magnetic resonance imaging (MRI) and 2,3,5-triphenyltetrazolium chloride (TTC) staining were employed to calculate the infarct volume. The cerebral cortex and corpus striatum in the ischemic penumbra area were examined microscopically for pathological changes. In SHR, NBP pre- and post-treatment significantly lowered neurological deficit scores, reduced infarct volume, and minimized pathological changes in the penumbra area when compared to oil-vehicle treated controls. In WKY, these beneficial effects were observed only in the post-treatment group. The beneficial effects of NBP post-treatment were greater in WKY than in SHR. Results indicated that NBP could exert both preventive and therapeutic effects on ischemic stroke in SHR, but only exerted therapeutic effect in WKY.

Cigarette smoking as a risk factor for influenza-associated mortality: evidence from an elderly cohort

Please cite this paper as: Wong et al. (2012) Cigarette smoking as a risk factor for influenza‐associated mortality: evidence from an elderly cohort. Influenza and Other Respiratory Viruses 7(4), 531–539.

Background  The effects of individual lifestyle factors on the mortality risk after influenza infection have not been explored.

Objectives  In this study, we assessed the modifying effects of cigarette smoking on mortality risks associated with influenza in a cohort of Hong Kong elders with a follow‐up period of 1998–2009.

Methods  We used the Cox proportional hazards model with time‐dependent covariates of weekly proportions of specimens positive for influenza (termed as influenza virus activity), to calculate the hazard ratio of mortality associated with a 10% increase in influenza virus activity for never, ex‐ and current smokers. Other individual lifestyle and socioeconomic factors as well as seasonal confounders were also added into the models.

Results  The overall hazard ratio associated with influenza was 1·028 (95% confidence interval, 1·006, 1·051) for all natural cause mortality and 1·035 (1·003, 1·068) for cardiovascular and respiratory mortality. We found that influenza‐associated hazard ratio was greater in current and ex‐smokers than in never smokers for mortality of all natural causes, cardiovascular and respiratory diseases.

Conclusions  The findings suggest that smoking might increase influenza‐associated mortality risks among elders.

Serotonin and its receptors in the human CNS with new findings - a mini review

Serotonin (5-hydroxytryptamine, 5-HT) is well known to be closely associated with emotional disorders, such as depression and schizophrenia. The seven main members of 5-HT receptor family including the different subtypes are involved in the functional pathways in the brain and their balance in activity helps to maintain the normal mental stability. As any detrimental changes in the 5-HT system is believed to alter emotion in human, different drugs including serotonin reuptake inhibitors (SSRIs) are nowadays commonly used as anti- depressives. In this review, 5-HT(1A) and 5-HT(2A) receptors and serotonergic positive cells in the human were highlighted in particular. It is hoped that this review will give a map of these major 5-HT receptors and serotonergic neurons in the human CNS to facilitate further deciphering of their functions.

A 1-year randomized controlled trial comparing mind body exercise (Tai Chi) with stretching and toning exercise on cognitive function in older Chinese adults at risk of cognitive decline

OBJECTIVES

To compare the effectiveness of Chinese-style mind-body exercise (24 forms simplified Tai Chi) versus stretching and toning exercise in the maintenance of cognitive abilities in Chinese elders at risk of cognitive decline.

DESIGN

A 1-year single-blind cluster randomized controlled trial.

SETTINGS

Community centers and residential homes for elders in Hong Kong.

PARTICIPANTS

A total of 389 subjects at risk of cognitive decline (Clinical Dementia Rating, CDR 0.5 or amnestic-MCI) participated in an exercise intervention program.

INTERVENTION

A total of 171 subjects were trained with Tai Chi (Intervention [I]) and 218 were trained with stretching and toning exercise (Control [C]).

METHODS

Cognitive and functional performance were assessed at the baseline, and at 5, 9, and 12 months. Data were analyzed using multilevel mixed models. Primary outcomes included progression to clinical dementia as diagnosed by DSM-IV criteria, and change of cognitive and functional scores. Secondary outcomes included postural balance measured by the Berg Balance Scale neuropsychiatric and mood symptoms measured by the Neuropsychiatric Inventory, and Cornell Scale for Depression in Dementia.

RESULTS

At 1 year, 92 (54%) and 169 (78%) participants of the I and C groups completed the intervention. Multilevel logistic regression with completers-only analyses controlled for baseline differences in education revealed that the I group had a trend for lower risk of developing dementia at 1 year (odds ratio 0.21, 95% CI 0.05-0.92, P = .04). The I group had better preservation of CDR sum of boxes scores than the C group in both intention-to-treat (P = .04) and completers-only analyses (P = .004). In completers-only analyses, the I group had greater improvement in delay recall (P = .05) and Cornell Scale for Depression in Dementia scores (P = .02).

CONCLUSION

Regular exercise, especially mind-body exercise with integrated cognitive and motor coordination, may help with preservation of global ability in elders at risk of cognitive decline; however, logistics to promote long-term practice and optimize adherence needs to be revisited.

Association between HbA1c and cardiovascular disease mortality in older Hong Kong Chinese with diabetes

OBJECTIVE

To examine the association between baseline HbA(1c) level and mortality attributable to all-cause, cardiovascular disease, coronary heart disease and stroke.

METHODS

A total of 2137 Chinese aged 65 years or above attending the Elderly Health Service, Department of Health, Hong Kong, with diagnosed diabetes had HbA(1c) measured during 1998 to 2000 and were followed up to 2009. Information on socio-economic position, lifestyle factors and disease history was collected. Hazard ratios and 95% confidence intervals with adjustment for potential confounders were calculated using Cox's proportional hazards models.

RESULTS

After an average of 7.9 years of follow-up, 540 participants had died. After adjusting for potential confounders, higher HbA(1c) (≥ 69 mmol/mol, 8.5%) increased the risk of cardiovascular disease (hazard ratio 2.11;95% CI 1.37-3.25) and stroke mortality (hazard ratio 2.43; 95% CI 1.06-5.55) compared with HbA(1c) of 58-68 mmol/mol (7.5-8.4%), and increased the risk of all-cause (hazard ratio 1.41; 95% CI 1.06-1.86) and coronary heart disease mortality (hazard ratio 2.44; 95% CI 1.11-5.37) compared with HbA(1c) of 48 mmol/mol (6.5%) or less. Analysis of HbA(1c) as a continuous variable showed that every XX mmol/mol (1%) increase in HbA(1c) decreased stroke mortality risk by 51% in those with HbA(1c) level less than 48 mmol/mol (6.5%) and increased stroke mortality risk by 30% in those with an HbA(1c) level of 48 mmol/mol (6.5%) or higher, suggesting a U-shaped association between HbA(1c) and stroke mortality.

CONCLUSION

High HbA(1c) predicted excess risk of all-cause, cardiovascular disease, coronary heart disease and stroke mortality. The question of whether low HbA(1c) increases mortality in older patients with diabetes needs further investigation.

Long-term ketamine and ketamine plus alcohol treatments produced damages in liver and kidney

Ketamine is one of the common recreational drugs used in rave parties and it is frequently taken with alcohol. In spite of this, the potential toxicity of ketamine in liver and kidney has not been fully documented. In this study, ICR mice were treated for periods of 6, 16 and 28 weeks with 30 mg/kg ketamine injected daily intraperitoneally, and together with alcohol (0.5 ml of 10% alcohol for each mouse) during the last 4 weeks of the treatment periods. Our experimental results showed significant damage in liver, including fatty degeneration of liver cells, fibrosis and increase in liver glutamic oxaloacetic transaminase, proliferative cell nuclear antigen and lactate dehydrogenase after 16 weeks of treatment with ketamine. Hydropic degenerations of the kidney tubules were observed as early as 6 weeks of treatment. Long-term ketamine administration (28 weeks) led to atresia of glomeruli in the kidney. Proteinuria was confirmed in the 67% of the ketamine-treated animals after 28 weeks of treatment. It was apparent that ketamine when taken chronically (16 weeks of treatment and thereafter) affected both liver and kidney definitively. The damages in both liver and kidney of these mice were more severe when the animals were treated with both ketamine and alcohol.

Influenza vaccination and hospitalisation in Elderly Health Centres

1. A cohort of Elderly Health Centres was examined to determine whether influenza vaccination decreased hospitalisation and mortality. 2. In the influenza season, influenza vaccination reduced all-cause mortality by half and cardiorespiratory hospitalisation by a quarter. The extent to which influenza vaccination protects older people from serious morbidity and mortality needs to be confirmed in appropriately designed studies, so that scarce health care resources can be used effectively

Older people with diabetes have higher risk of depression, cognitive and functional impairments: implications for diabetes services

OBJECTIVES

To examine the relationship between diabetes and impairments in functional and cognitive status as well as depression in older people.

DESIGN

Cross-sectional study.

SETTING

Elderly Health Centres (EHC) in Hong Kong.

PARTICIPANTS

66,813 older people receiving baseline assessment at EHC in 1998 to 2001.

MEASUREMENTS

Diabetes status was defined by self-report and blood glucose tests. Functional status was assessed by 5 items of instrumental activities of daily living (IADL) and 7 items of activities of daily living (ADL). Cognitive status was screened by the Abbreviated Mental Test-Hong Kong version (AMT). Depressive symptoms were screened by the Geriatric Depression Scale-Chinese version (GDS).

RESULTS

Among the subjects, 10.4% reported having regular treatment for diabetes, 3.4% had diabetes but were not receiving regular treatment, and 86.2% did not have diabetes. After controlling for age, sex and education level, those having regular treatment for diabetes were 1.7 times more likely (OR=1.65, 95% CI: 1.51-1.80) to have functional impairment, 1.3 times more likely (OR=1.28, 95% CI: 1.11-1.48) to have cognitive impairment and 1.3 times more likely (OR=1.35, 95% CI: 1.25-1.46) to have depression, than older people without diabetes.

CONCLUSION

Older people with diabetes may be less capable of managing the disease than the younger ones as a result of increased risk of both physical and cognitive impairment. This study provided further evidence for the need of an international consensus statement regarding care of diabetes in older people.

Cardiotoxicity induced in mice by long term ketamine and ketamine plus alcohol treatment

Increased use of ketamine as a recreational drug in rave party has raised lots of social concerns. Although its toxicity on the central nervous system (CNS) and urinary system had been reported, its potential adverse effects on the heart is still not addressed. Using our long term ketamine addiction model in which, 1-month-old ICR mice were given ketamine intraperitoneally (i.p. 30 mg/kg) for different study periods (6 weeks, 16 weeks and 28 weeks). The electrocardiogram (ECG) and the level of troponin as well as the presence of lactate dehydrogenase were used together to determine the cardiac function of mice. ST elevations were observed in 30% of mice from 6 weeks onwards. Concomitant increase in troponin in serum and presence of lactate dehydrogenase positive cardiac cells were taken together to indicate cardiac damages. The potential interactive effects of alcohol (ethanol) and ketamine were also addressed and 0.5 ml of 10% ethanol was administrated additionally to the mice daily and orally for the last 4 weeks in the 28-week long-term ketamine treated animals. The cardiac functions of these mice deteriorated more severely as indicated by further rise in troponin levels. In addition, high number of lactate dehydrogenase positive cardiac cells and abnormal ECGs in both ketamine and ketamine plus alcohol treated models also gave coherent conclusions.

Downregulation in the human and mice cerebella after ketamine versus ketamine plus ethanol treatment

To study the deleterious effects of ketamine and the potential interaction effects between ethanol and ketamine on the cerebellum, functional magnetic resonance imaging (fMRI) tests were performed on the habitual ketamine users (n = 3) when they flexed and extended their upper limbs. Another fMRI test was performed on the same participants in which they consumed alcohol (12%, 200 mL) 1 h before the test. Downregulation on the activity of cerebellum was observed and the level of activation in the cerebellum decreased dramatically in habitual ketamine users with alcohol consumption before the test. Further studies were performed by using male ICR mice receiving treatment of ketamine only [30 mg kg(-1) intraperitoneally (i.p.)] or ethanol only everyday (0.5 mL 12% orally) and those with coadministration of the above dosages of ketamine and ethanol for 3 months. Fewer Purkinje cells were observed in the cerebellar sections of ketamine treated mice under silver staining. For TUNEL test, a significant increase in the apoptotic cells were observed in the cerebella of the ketamine treated mice (P = 0.016) and of those with co-administration of ketamine and ethanol (P < 0.001), when compared with the control. A statistical significance (P < 0.001) in two-way ANOVA test indicated that there might be an interactive mechanism between ethanol and ketamine acting on the cerebellum.

Interim follow-up of a randomized controlled trial comparing Chinese style mind body (Tai Chi) and stretching exercises on cognitive function in subjects at risk of progressive cognitive decline

OBJECTIVES

We reported the interim findings of a randomized controlled trial (RCT) to examine the effects of a mind body physical exercise (Tai Chi) on cognitive function in Chinese subjects at risk of cognitive decline.

SUBJECTS

389 Chinese older persons with either a Clinical Dementia Rating (CDR 0.5) or amnestic-MCI participated in an exercise program. The exercise intervention lasted for 1 year; 171 subjects were trained with 24 forms simplified Tai Chi (Intervention, I) and 218 were trained with stretching and toning exercise (Control, C). The exercise comprised of advised exercise sessions of at least three times per week.

RESULTS

At 5th months (2 months after completion of training), both I and C subjects showed an improvement in global cognitive function, delayed recall and subjective cognitive complaints (paired t-tests, p < 0.05). Improvements in visual spans and CDR sum of boxes scores were observed in I group (paired t-tests, p < 0.001). Three (2.2%) and 21(10.8%) subjects from the I and C groups progressed to dementia (Pearson chi square = 8.71, OR = 5.34, 95% CI 1.56-18.29). Logistic regression analysis controlled for baseline group differences in education and cognitive function suggested I group was associated with stable CDR (OR = 0.14, 95%CI = 0.03-0.71, p = 0.02).

CONCLUSIONS

Our interim findings showed that Chinese style mind body (Tai Chi) exercise may offer specific benefits to cognition, potential clinical interests should be further explored with longer observation period.

Impact of income and education on drug purchasing decisions in Hong Kong Chinese cancer patients: a pilot study

BACKGROUND

The affordability of diagnostic, preventive and therapeutic interventions is a global concern, particularly in the developing world. To clarify the educational and financial factors that influence purchasing decisions, we conducted a survey of Hong Kong cancer patients across a broad social spectrum.

METHODS

A questionnaire was designed to assess the effect of costs on purchasing decisions relating to six drug-related variables: efficacy, tolerability, convenience, safety, peer pressure, and uncertainty. Validation of the original 31-part survey resulted in a final set of 22 core questions that was administered to 51 consecutive oncology patients who were characterized in terms of varying household income and educational level.

RESULTS

Most respondents (87.6%) were Hong Kong-born or mainland Chinese. There was a strong correlation between household income and education. Demand for drug tolerability and safety was high and cost-inelastic across all educational and income groups. An unexpected finding was that patients from low-income/education households were keen to purchase costly medications (whether Western, or Chinese herbs) of reputed high efficacy, whereas patients from middle-income/-education backgrounds were more negatively influenced by considerations of cost. Only the most affluent and well-educated patients valued overall survival above disease-free survival when making drug purchasing decisions; this cohort was also the least influenced by peer pressure, and the most willing to pay extra for drugs offering more convenience alone.

CONCLUSION

Low-income/education Asian patients had paradoxically high expectations of costly drug interventions. Although larger studies addressing this issue are needed to confirm these conclusions, public education initiatives aimed at protecting low-income/education patients from exploitation or disappointment may be desirable.

Sequential introduction of single room isolation and hand hygiene campaign in the control of methicillin-resistant Staphylococcus aureus in intensive care unit

Background

After renovation of the adult intensive care unit (ICU) with installation of ten single rooms, an enhanced infection control program was conducted to control the spread of methicillin-resistant Staphylococcus aureus (MRSA) in our hospital.

Methods

Since the ICU renovation, all patients colonized or infected with MRSA were nursed in single rooms with contact precautions. The incidence of MRSA infection in the ICU was monitored during 3 different phases: the baseline period (phase 1); after ICU renovation (phase 2) and after implementation of a hand hygiene campaign with alcohol-based hand rub (phase 3). Patients infected with extended spectrum beta-lactamase (ESBL)-producing Escherichia coli and Klebsiella species were chosen as controls because they were managed in open cubicles with standard precautions.

Results

Without a major change in bed occupancy rate, nursing workforce, or the protocol of environmental cleansing throughout the study period, a stepwise reduction in ICU onset nonbacteraemic MRSA infection was observed: from 3.54 (phase 1) to 2.26 (phase 2, p = 0.042) and 1.02 (phase 3, p = 0.006) per 1000-patient-days. ICU onset bacteraemic MRSA infection was significantly reduced from 1.94 (phase 1) to 0.9 (phase 2, p = 0.005) and 0.28 (phase 3, p = 0.021) per 1000-patient-days. Infection due to ESBL-producing organisms did not show a corresponding reduction. The usage density of broad-spectrum antibiotics and fluoroquinolones increased from phase 1 to 3. However a significant trend improvement of ICU onset MRSA infection by segmented regression analysis can only be demonstrated when comparison was made before and after the severe acute respiratory syndrome (SARS) epidemic. This suggests that the deaths of fellow healthcare workers from an occupational acquired infection had an overwhelming effect on their compliance with infection control measures.

Conclusion

Provision of single room isolation facilities and promotion of hand hygiene practice are important. However compliance with infection control measures relies largely on a personal commitment, which may increase when personal safety is threatened.

Getting lost in the community: a phone survey on the community-dwelling demented people in Hong Kong

OBJECTIVE

Research from Western countries reported that the incidence rate of dementia patients getting lost in the community ranged from 30 to 60%. It had imposed significant burden on the caregivers. In the current study, we investigated the situation on the incidents of getting lost in a densely populated as well as homogenous community environment.

METHODS

Two hundred and fifty one caregivers of older adults with demented people who had either used dementia day care service or participated in a community survey were interviewed on the telephone. Respondents were asked on older adult's experience of getting lost in the community and their mode of care. Correlating factors of such incidents were examined.

RESULTS

The overall prevalence of lost history in our subjects was 27.5%. The subjects recruited from day care center were much more likely than those recruited from the community survey to have lost history (39.2% vs. 7.5%, p < 0.0001, chi(2) test). Greater degrees of cognitive decline were associated with greater chance of having had lost episodes. Immobility was associated with lower risk. Both the older people and their caregivers had reported significant degrees of psychological disturbances after the incidents.

CONCLUSION

Demented people with greater degrees of cognitive decline and with mobility maintained are at greater risk of getting lost.

Modality of physical exercise and cognitive function in Hong Kong older Chinese community

OBJECTIVE

We reported the association between modality of Physical Exercise and cognitive function in 782 older Chinese adults assessed in the second phase of a population survey for dementia in Hong Kong.

METHODS

Profiles of physical exercise was measured by a questionnaire (no exercise, stretching, aerobic and mind-body exercise). Cognitive Assessments included the CMMSE, ADAS-Cog, and Category Verbal Fluency Test (CVFT).

RESULTS

The aerobic and mind body exercise groups with longer exercise habits (>5 years) had higher scores in most cognitive tests (Kruskal Wallis tests, p < 0.01). Beneficial effects were more significant in the young old group from 65- 75 years.

CONCLUSIONS

Possible age related specific effects of aerobic and mind body exercise on cognitive reserve are worthy of further exploration.

Clinical correlates of Parkinsonian signs in community- dwelling Chinese older persons: a population based study

BACKGROUND AND OBJECTIVE

This study examined the clinical correlates of parkinsonian signs including neuropsychiatric symptoms, cognitive impairment and medical illness burden in the community-dwelling non-demented Chinese elderly.

METHODS

A random sample of 765 Chinese elderly subjects from a thematic household survey was recruited. There were 389 normal elderly controls (Clinical Dementia Rating [CDR] 0) (NC) and 376 subjects with questionable dementia (CDR 0.5). The subjects with questionable dementia (CDR 0.5) were categorized into two groups: a MCI group (n = 291) and a very mild dementia (VMD) group (n = 85). Parkinsonian signs were measured by Unified Parkinson Disease Rating Scale- motor scale (UPDRS). The clinical correlates were investigated in each group.

RESULTS

UPDRS motor score was associated with age, cumulative medical illness burden and cerebrovascular accidents in the normal control and MCI groups. It correlated negatively with MMSE scores in the NC group. It was associated with presence of soft signs in the NC and MCI groups; and apathy in the VMD group.

CONCLUSION

Neuropsychiatric symptoms, cognitive impairment and vascular risk factors had different patterns of associations with parkinsonian signs in the older persons with different degree of cognitive impairment.

Diabetic control and risk of tuberculosis: a cohort study

Diabetes mellitus is associated with tuberculosis. A cohort of 42,116 clients aged 65 years or more, enrolled at 18 Elderly Health Service centers in Hong Kong in 2000, were followed up prospectively through the territory-wide tuberculosis registry for development of tuberculosis from 3 months after enrollment to December 31, 2005, by use of their identity card numbers as unique identifier. The effects of diabetes mellitus and diabetic control on tuberculosis risk were assessed with adjustment for sociodemographic and other background variables. Diabetes mellitus was associated with a modest increase in the risk of active, culture-confirmed, and pulmonary (with or without extrapulmonary involvement) but not extrapulmonary (with or without pulmonary involvement) tuberculosis, with adjusted hazard ratios of 1.77 (95% confidence interval: 1.41, 2.24), 1.91 (95% confidence interval: 1.45, 2.52), 1.89 (95% confidence interval: 1.48, 2.42), and 1.00 (95% confidence interval: 0.54, 1.86), respectively. Diabetic subjects with hemoglobin A1c <7% at enrollment were not at increased risk. Among diabetic subjects, higher risks of active, culture-confirmed, and pulmonary but not extrapulmonary tuberculosis were observed with baseline hemoglobin A1c > or =7% (vs. <7%), with adjusted hazard ratios of 3.11 (95% confidence interval: 1.63, 5.92), 3.08 (95% confidence interval: 1.44, 6.57), 3.63 (95% confidence interval: 1.79, 7.33), and 0.77 (95% confidence interval: 0.18, 3.35), respectively.

Prevalence of clinically significant depressive symptoms in an epidemiologic sample of community-dwelling elders with milder forms of cognitive impairment in Hong Kong SAR

BACKGROUND

Depression and cognitive impairment in later-life have great bearings on public health. The two conditions often co-occur and have mutual implications on short-term risk and long-term prognosis.

METHOD

A two-phase epidemiologic survey on the prevalence of dementia in elders aged 60 and over was conducted in Hong Kong in 2005-2006. In the first phase, 6,100 randomly selected community dwelling elders were assessed with Cantonese version of Mini-Mental State Examination (C-MMSE) and Abbreviated Memory Inventory for Chinese (AMIC). Two thousand and seventy-three subjects were screened positive and invited for second phase cognitive and psychiatric assessment. 35.5% of screen-positive subjects participated in Phase 2 assessment conducted by psychiatrists for diagnosis of dementia. Severity of dementia was determined using Clinical Dementia Rating Scale (CDR). Cornell Scale for Depression in Dementia (CSDD) and a structured bedside cognitive battery were also administered to each subject.

RESULTS

1.7% of subjects with CDR 0.5 and 5.9% of subjects with CDR 1 had clinically significant depressive symptoms (>or= 8 on CSDD). Score on CSDD correlated positively with duration of cognitive symptoms, scores on CIRS and CMMSE in linear regression model. In a logistic regression model, male gender, duration of cognitive symptoms, CIRS and CMMSE was associated with increased risk for clinically significant depressive symptoms.

CONCLUSIONS

In our sample, milder forms of cognitive impairment were associated with increased risk for depression in the presence of other risk factors such as male gender, higher physical illness burden and longer duration of cognitive symptoms.

Prevalence of very mild and mild dementia in community-dwelling older Chinese people in Hong Kong

INTRODUCTION

In this report, the results of a household survey were used to examine the prevalence of very mild and mild dementia in Chinese older persons in Hong Kong.

METHODS

The study adopted a two-phase design. At Phase 1, 6100 subjects were screened using the Cantonese version of the Mini-mental State Examination (MMSE) and a short memory inventory. At Phase 2, 2073 subjects were screened positive and 737 were evaluated by psychiatrists. Clinical Dementia Rating (CDR) and cognitive assessment were used for diagnosis of dementia. Very mild dementia (VMD) was defined as a global CDR of 0.5, with memory and non-memory subscale scores of 0.5 or more. Mild dementia was classified for subjects with a CDR of 1.

RESULTS

The overall prevalence of VMD and mild dementia for persons aged 70 years or above was 8.5% (95%CI: 7.4-9.6) and 8.9% (95%CI: 7.8-10.0) respectively. Among subjects with clinical dementia, 84.6% had mild (CDR1) dementia. Logistic regression analyses revealed that older age, lower educational level and significant cerebrovascular risk factors were risk factors for dementia, while regular physical exercise was a protective factor for dementia.

CONCLUSIONS

A sizable proportion of community-living subjects suffered from milder forms of dementia. They represent a high risk for early intervention to reduce potential physical and psychiatric morbidity.

Screening of mild cognitive impairment in Chinese older adults--a multistage validation of the Chinese abbreviated mild cognitive impairment test

OBJECTIVE

To develop a short cognitive test for screening mild cognitive impairment (MCI) in Hong Kong Chinese older adults.

METHODS

The Chinese Abbreviated MCI (CAMCI) test was developed with a multistage process. In phase 1, a short version of the cognitive test comprising a 1-min animal fluency test and a 10-min delayed word list recall was developed and tested in 578 volunteers (community-dwelling active elderly persons). In phase 2, the CAMCI test was validated in an independent and randomly recruited sample of 459 participants in a community survey. Additionally, the predictive significance of the CAMCI test was evaluated in a group of 196 subjects assessed in phase 1 for conversion to clinical dementia at 20 months' follow-up. The discriminating power of the CAMCI test in differentiating MCI from normal control (NC) and mildly demented subjects was compared with Mini Mental State Examination (MMSE) and Alzheimer's Disease Assessment Scale-Cognitive (ADAS-Cog) subscales.

RESULTS

The CAMCI test was found to have high discriminating power in differentiating NC from MCI and mildly demented subjects in the phase 1 volunteer sample. The receiver operating characteristics (ROC) revealed an area under the curve (AUC) of 0.91. The ROC were further validated in the phase 2 sample. The AUC of the CAMCI test was compared with MMSE and ADAS-Cog subscales. The short MCI test was comparable to the ADAS-Cog subscale in discriminating NC from MCI and demented subjects (chi(2) test, p = n.s.). Logistic regression analysis was carried out to determine significant baseline predictors for conversion to dementia at phase 3 follow-up. Both ADAS-Cog total [Exp(B) = 1.115, p = 0.028] and CAMCI [Exp(B) = 0.88, p = 0.045] scores were significant predictors for dementia status at follow-up.

CONCLUSION

The CAMCI test is able to discriminate NC from MCI and mild dementia in Hong Kong Chinese older adults. Its potential for large-scale community screening for early detection of cognitive impairment in late life should be emphasized and explored.

Lower risk of tuberculosis in obesity

BACKGROUND

Obesity is increasingly prevalent in both developed and developing areas. Although undernutrition is well associated with tuberculosis, few studies have systematically examined the association with obesity. Method A cohort of 42 116 individuals 65 years or older enrolled at 18 health centers for elderly patients in Hong Kong, China (which has a tuberculosis incidence of approximately 90 per 100,000 population), in 2000 were followed up prospectively through the territory-wide tuberculosis registry for the development of active tuberculosis from 3 months after enrollment until December 31, 2005, using the identity card number as the unique identifier. The association with body mass index (BMI; calculated as weight in kilograms divided by the square of height in meters), as categorized by the Asian standards, was assessed with the control of other baseline characteristics.

RESULTS

Obese (BMI>or=30) and overweight (BMI, 25 to <30) individuals were at significantly lower risks of developing active tuberculosis than normal-weight individuals (BMI, 18.5 to <25), with hazard ratios (95% confidence intervals) of 0.36 (0.20-0.66) and 0.55 (0.44-0.70), respectively, after adjustment for baseline demographic, social, and clinical variables. An inverse linear association was observed predominantly for pulmonary but not extrapulmonary tuberculosis. This association persisted after controlling for potential confounders or excluding individuals with known tuberculosis risk factors.

CONCLUSIONS

Obesity is associated with a lower risk of active pulmonary tuberculosis in the older population of Hong Kong. The presence of such a strong but selective association across the whole spectrum of BMI could have major biological, clinical, and/or epidemiological implications. Further studies are indicated to explore the underlying mechanisms, potential clinical utilities, and possible epidemiological consequences.

A novel missense RP1 mutation in retinitis pigmentosa

AIMS

More than 20 mutations associated with retinitis pigmentosa (RP) have been identified in the retinitis pigmentosa 1 (RP1) gene, all of them leading to the production of a truncated protein without 50-70% of the C-terminal of the RP1 protein. RP1 was recently found to be a microtubule-associated protein (MAP) and responsible for the organisation of the photoreceptor outer segment. The N-terminal doublecortin (DCX) domain of RP1 is essential for its function. But how the C-terminal of the protein affects its function is still not known. This study aims to get a better understanding of the RP1 gene by mutation screening on RP patients.

METHODS

Peripheral blood was taken from 72 RP patients. Together with 101 RP patients and 190 control subjects previously reported, mutation screening was performed by polymerase chain reaction (PCR) and direct sequencing. Statistical analysis was performed using SPSS.

RESULTS

Two novel missense sequence changes, D984G and C727W, and one novel variant, 6492T>G, at the 3' untranslated region were found. They were not found in 190 control subjects. D984G causes RP. It creates two possible N-myristoylation sites according to PROSITE. C727W does not segregate with RP in the family. It abolishes an N-myristoylation site. R872H, a previously reported polymorphism, was predominantly present in control subjects (P=0.001).

CONCLUSIONS

Our results suggest that disruption of the C-terminal of RP1 may be associated with the development of RP, and the possible involvement of the RP1 polypeptide downstream of its DCX domain in normal RP1 function.

A novel genetic study of Chinese families with autosomal recessive retinitis pigmentosa

Autosomal recessive retinitis pigmentosa (arRP) is the commonest form of RP worldwide. To date 22 loci have been implicated in the pathogenesis of this disease; however none of these loci independently account for a significant proportion of recessive RP. Linkage studies of arRP in consanguineous families have been mainly based on homozygosity mapping, but this strategy cannot be applied in the case of non-consanguineous families. Therefore, we implemented a systematic approach for identifying the disease locus in three non-consanguineous Chinese families with arRP. Initially, linkage analysis using SNPs/microsatellite markers or mutation screening of known arRP genes excluded all loci/genes except RP25 on chromosome 6. Subsequently a whole genome scan for the three families using the 10K GeneChip Mapping Array was performed, in order to identify the possible disease locus. To the best of our knowledge this is the first report on the utilisation of the 10K GeneChip to study linkage in non-consanguineous Chinese arRP. This analysis indicates that the studied families are probably linked to the RP25 locus, a well defined arRP locus in other populations. The identification of another ethnic group linked to RP25 is highly suggestive that this represents a major locus for arRP.

A community model of group therapy for the older patients with chronic obstructive pulmonary disease: a pilot study

OBJECTIVE

A community-based programme for chronic obstructive pulmonary disease (COPD) patients in group sessions is designed, and the feasibility, acceptability and physical and psychosocial outcomes evaluated.

METHODS

Patients with COPD discharged from hospital, or those attending specialist outpatient clinic, with a history of hospital admission owing to COPD in the preceding 12 months were recruited. Those who had malignancy or were housebound were excluded. Group sessions were arranged once a week in a Community Centre, and consisted of two hourly sessions. The components of each session consist of education regarding the disease, breathing techniques, use of oxygen and other medication, smoking cessation, nutrition, dyspnoea management skills, relaxation and energy conservation techniques, introduction of social and community support, and strengthening as well as aerobic exercises. Assessments before and after intervention include lung function, 6 minutes walk test (6MWT), general Health Questionnaire (GHQ), the St. George's Respiratory Questionnaire (SGRQ), and a COPD knowledge Questionnaire. A programme evaluation was carried out using questionnaire and group discussions.

RESULTS

Forty-four subjects were recruited, with 75% completing the programme, and 20% with drawing for unavoidable reasons. Statistically significant improvement was noted in all domains of the GHQ, SGRQ, and knowledge test, while the mean 6MWT improved, although statistical significance was not reached. Subjects were enthusiastic about the provision of this service in helping them cope with the disease through empowerment and mutual support.

CONCLUSION

A group community intervention programme for COPD patients is feasible and acceptable, with positive psychosocial outcomes. Such a model could be further developed and cost-effectiveness evaluated as a model of chronic disease management in the community.

Prevalence of subclinical infection and transmission of severe acute respiratory syndrome (SARS) in a residential care home for the elderly

OBJECTIVE

To ascertain the prevalence of subclinical severe acute respiratory syndrome-coronavirus (SARS-CoV) infection and study the transmission of SARS-CoV in a local outbreak at a residential care home for the elderly.

DESIGN

Cross-sectional study.

SETTING

A residential care home for the elderly in Hong Kong with a local outbreak of SARS.

PARTICIPANTS

Residents and staff in the residential care home who had contact with three patients with SARS (residents A and B, and staff C).

MAIN OUTCOME MEASURES

Blood samples were tested for total antibodies to SARS-CoV by immunofluorescence antibody test. The transmission of SARS was elucidated based on information from standardised questionnaires, and records of investigation and surveillance by the Department of Health.

RESULTS

Among the 90 eligible residents, three died, one moved out, and 19 refused to participate. Of the 32 eligible staff, six refused to participate. None of the remaining 93 participants tested positive for antibody to SARS-CoV. Based on the chronological order, resident A might have transmitted infection to resident B and staff C. Sitting close to the bathroom doorway while resident A took a shower was the only contact of resident B with resident A. The only opportunity for staff C to have contact with body fluids/excreta of resident A was in the handling of rubbish from the resident's room.

CONCLUSION

Subclinical SARS-CoV infection was rare in a residential care home for the elderly with an outbreak of SARS. Nonetheless the close working and living conditions for staff and residents in such a home may facilitate transmission of SARS despite vigilant precautionary measures.