Effectiveness of CoronaVac and BNT162b2 Vaccines Against Severe Acute Respiratory Syndrome Coronavirus 2 Omicron BA.2 Infections in Hong Kong.

There is limited evidence on vaccine effectiveness against asymptomatic or mild Omicron infections. We estimated that recent third doses of messenger RNA or inactivated vaccines reduced the risk of self-reported infection by 52% (95% confidence interval, 17%-73%) among randomly sampled adults during the Omicron BA.2-dominated surge in Hong Kong.

A population-based study on healthcare-seeking behaviour of persons with symptoms of respiratory and gastrointestinal-related infections in Hong Kong.

BACKGROUND: Studies on healthcare-seeking behaviour usually adopted a patient care perspective, or restricted to specific disease conditions. However, pre-diagnosis symptoms may be more relevant to healthcare-seeking behaviour from a patient perspective. We described healthcare-seeking behaviours by specific symptoms related to respiratory and gastrointestinal-related infections. METHODS: We conducted a longitudinal population-based telephone survey in Hong Kong. We collected data on healthcare-seeking behaviour specific to symptoms of respiratory and gastrointestinal-related infections and also associated demographic factors. We performed descriptive analyses and estimated the proportion of participants who sought medical consultation, types of services utilized and duration from symptom onset to healthcare seeking, by different age groups. Post-stratification was used to compensate non-response and multiple imputation to handle missing and right-censored data. RESULTS: We recruited 2564 participants who reported a total of 4370 illness episodes and 7914 symptoms. Fatigue was the most frequently reported symptom, followed by headache and runny nose, with 30-day incidence rate of 9.1, 7.7, and 7.7% respectively. 78% of the participants who had fever sought medical consultation, followed by those with rash (60%) and shortness of breath (58%). Older adults (aged ≥55y) who had symptoms including fever, sore throat, and headache had a significantly higher consultation rate comparing to the other age groups. The 30-day incidence rates of influenza-like illness (ILI) and acute respiratory illness (ARI) were 0.8 and 7.2% respectively, and the consultation rates among these participants were 91 and 64%. Private general practitioner clinics was the main service utilized by participants for most of the symptoms considered, especially those related to acute illness such as fever, diarrhoea and vomiting. Chinese medicine clinics were mostly likely to be visited by participants with low back pain, myalgia and fatigue. Among participants who have sought medical services, most were within 3 days of symptom onset. CONCLUSIONS: Healthcare-seeking behaviour were different by symptoms and age. Characterization of these patterns provides crucial parameters for estimating the full burden of common infectious diseases from facility-based surveillance system, for planning and allocation of healthcare resources.

Effects of Helicobacter pylori Treatment on Incidence of Gastric Cancer in Older Individuals.

BACKGROUND & AIMS: Although eradication of Helicobacter pylori infection reduces the risk of gastric cancer, few data are available on its effects in older subjects. We compared the age-specific risk of gastric cancer in a large cohort of subjects who received H pylori eradication therapy vs a matched general population. METHODS: We searched the Hospital Authority database of Hong Kong to identify individuals with H pylori infection who had received a course of clarithromycin-containing eradication therapy from January 2003 through December 2012. We compared the gastric cancer incidence in this cohort with the expected incidence for the local general population by retrieving the gastric cancer incidence of the age- and sex-matched population from 2003 through 2014 (the latest available year) from the Hong Kong Cancer Registry. The primary outcome was the incidence of gastric cancer development in the cohort treated for H pylori infection vs the expected number of gastric cancer cases in the general population. Analyses were conducted by a priori age groups of less than 40 years, 40-59 years, and 60 years or older. RESULTS: Among 73,237 subjects infected with H pylori who received eradication therapy, 200 (0.27%) developed gastric cancer during a median follow-up time of 7.6 years. Compared with the matched general population, the gastric cancer risk was significantly lower in subjects 60 years or older who had received H pylori treatment (standardized incidence ratio [SIR], 0.82; 95% confidence interval [CI], 0.69-0.97; P = .02) but not in younger groups. When data were stratified based on time from H pylori treatment (less than 5 years, 5-9 years, and 10 or more years), the risk of gastric cancer was significantly lower than the general population 10 or more years after eradication in the group 40-59 years old (SIR 0.32; 95% CI, 0.08-0.88; P = .04) and the group 60 years or older (SIR, 0.42; 95% CI, 0.42-0.84; P = .02) than the other age groups. CONCLUSIONS: In an analysis of data from a public hospital database on Hong Kong, we associated treatment of H pylori infection with a lower risk of gastric cancer, particularly in older subjects, 10 or more years after treatment.

Direct health-care cost utilization in Hong Kong inflammatory bowel disease patients in the initial 2 years following diagnosis.

BACKGROUND AND AIM: There are scanty data on the health-care utilization from Asia where the incidence of inflammatory bowel disease (IBD) is rising rapidly. We aim to determine the direct health-care costs in the first 2 years of diagnosis in an IBD cohort from Hong Kong and the factors associated with high cost outliers. METHODS: This is a retrospective cohort study that included patients newly diagnosed with IBD in a territory-wide IBD registry. Patients' clinical information, hospitalization records, investigations, and IBD treatments were retrieved for up to 2 years following diagnosis of IBD. RESULTS: Four hundred and thirty-five newly diagnosed IBD patients were included: 198 with Crohn's disease and 237 with ulcerative colitis. Total direct medical expenditure for this cohort 2 years after the IBD diagnosis was $7 072 710: hospitalizations (33%), 5-aminosalicylic acid (23%), imaging and endoscopy (17%), outpatient visits (10%), surgery (8%), and biologics (6%). Mean direct medical costs per patient-year were significantly higher for Crohn's disease ($9918) than ulcerative colitis ($6634; P, 0.001). The total direct health-care cost decreased significantly after transition to the second year (P < 0.01). High cost (> 90th percentile) outliers were associated with surgery (OR 7.1, 95% CI 2.9-17.2) and low hemoglobin on presentation (OR 0.83, 95% CI 0.70-0.96). CONCLUSIONS: Hospitalization and 5-aminosalicylic acid usage accounted for 56% of total direct medical costs in the first 2 years of our newly diagnosed IBD patients. Direct health-care costs were higher in the first year compared with the second year of diagnosis. Surgery and low hemoglobin on presentation were associated with high cost outliers.

Assessment of the impact of the vaccine pass policy on COVID-19 vaccine hesitancy and uptake among Chinese adults in Hong Kong.

BACKGROUND: Recognising the importance of attaining high vaccine coverage to mitigate the COVID-19 impact, a Vaccine Pass scheme was implemented during and after the first large Omicron wave with high mortality in older ages in Hong Kong in early 2022 requiring three doses by June 2022. We did not identify any studies evaluating the policy impact of vaccination mandates with vaccine uptake over whole policy period of time in a Chinese population. We aim to evaluate the impact of the Vaccine Pass policy on COVID-19 vaccine uptake in adults in a Chinese population in Hong Kong. METHODS: We analysed patterns in vaccine uptake and hesitancy using local data from population vaccine registry and 32 cross-sectional telephone surveys conducted from October 2021 to December 2022. The association of Vaccine Pass phases with vaccine uptake was examined using logistic regression analyses, taking into account covariates including self-risk perception, perceived self-efficacy in preventing COVID-19 and trust in government in pandemic control as well as physical distancing measures and demographics. RESULTS: The uptake of primary series and third doses was positively significantly associated with the successive stages of Vaccine Pass implementation (adjusted odds ratios ranged from 2.41 to 7.81). Other statistically significant drivers of uptake included age group, chronic condition, higher perceived personal susceptibility to COVID-19, higher trust in government, and higher educational attainment. CONCLUSION: Vaccine uptake in older adults was observed to have increased by a greater extent after the policy annoucement and implementation, under the contextual changes during and after a large Omicron wave with high mortality in Hong Kong in early 2022. Since the policy withdrawal the uptake of further booster doses has been very low in all ages. We suggest that improving voluntary booster uptake in older adults should be prioritized.

Comparison of control and transmission of COVID-19 across epidemic waves in Hong Kong: an observational study.

Background: Hong Kong contained COVID-19 for two years but experienced a large epidemic of Omicron BA.2 in early 2022 and endemic transmission of Omicron subvariants thereafter. We reflected on pandemic preparedness and responses by assessing COVID-19 transmission and associated disease burden in the context of implementation of various public health and social measures (PHSMs). Methods: We examined the use and impact of pandemic controls in Hong Kong by analysing data on more than 1.7 million confirmed COVID-19 cases and characterizing the temporal changes non-pharmaceutical and pharmaceutical interventions implemented from January 2020 through to 30 December 2022. We estimated the daily effective reproductive number (Rt) to track changes in transmissibility and effectiveness of community-based measures against infection over time. We examined the temporal changes of pharmaceutical interventions, mortality rate and case-fatality risks (CFRs), particularly among older adults. Findings: Hong Kong experienced four local epidemic waves predominated by the ancestral strain in 2020 and early 2021 and prevented multiple SARS-CoV-2 variants from spreading in the community before 2022. Strict travel-related, case-based, and community-based measures were increasingly tightened in Hong Kong over the first two years of the pandemic. However, even very stringent measures were unable to contain the spread of Omicron BA.2 in Hong Kong. Despite high overall vaccination uptake (>70% with at least two doses), high mortality was observed during the Omicron BA.2 wave due to lower vaccine coverage (42%) among adults ≥65 years of age. Increases in antiviral usage and vaccination uptake over time through 2022 was associated with decreased case fatality risks. Interpretation: Integrated strict measures were able to reduce importation risks and interrupt local transmission to contain COVID-19 transmission and disease burden while awaiting vaccine development and rollout. Increasing coverage of pharmaceutical interventions among high-risk groups reduced infection-related mortality and mitigated the adverse health impact of the pandemic. Funding: Health and Medical Research Fund.

Optimizing resource allocation for breast cancer prevention and care among Hong Kong Chinese women.

BACKGROUND: Recommendations about funding of interventions through the full spectrum of the disease often have been made in isolation. The authors of this report optimized budgetary allocations by comparing cost-effectiveness data for different preventive and management strategies throughout the disease course for breast cancer in Hong Kong (HK) Chinese women. METHODS: Nesting a state-transition Markov model within a generalized cost-effectiveness analytic framework, costs and quality-adjusted life-years (QALYs) were compared to estimate average cost-effectiveness ratios for the following interventions at the population level: biennial mass mammography (ages 40-69 years or ages 40-79 years), reduced waiting time for postoperative radiotherapy (by 15% or by 25%), adjuvant endocrine therapy (either upfront aromatase inhibitor [AI] therapy or sequentially with tamoxifen followed by AI) in postmenopausal women with estrogen receptor-positive disease, targeted immunotherapy in those with tumors that over express human epidermal growth factor receptor 2, and enhanced palliative services (either at home or as an inpatient). Usual care for eligible patients in the public sector was the comparator. RESULTS: In descending order, the optimal allocation of additional resources for breast cancer would be the following: a 25% reduction in waiting time for postoperative radiotherapy (in US dollars: $5000 per QALY); enhanced, home-based palliative care ($7105 per QALY); adjuvant, sequential endocrine therapy ($17,963 per QALY); targeted immunotherapy ($62,092 per QALY); and mass mammography screening of women ages 40 to 69 years ($72,576 per QALY). CONCLUSIONS: Given the lower disease risk and different age profiles of patients in HK Chinese, among other newly emergent and emerging economies with similar transitioning epidemiologic profiles, the current findings provided direct evidence to support policy decisions that may be dissimilar to current Western practice.

Cost-effectiveness analysis of first-line treatment for chronic hepatitis B in China.

OBJECTIVES: Hepatitis B virus infection is an important public health problem. We analysed the cost-effectiveness of the first-line therapies, including nucleotide analogues (namely tenofovir alafenamide fumarate (TAF), tenofovir disoproxil fumarate (TDF) and entecavir) and pegylated interferon (Peg-IFN) for patients with chronic hepatitis B (CHB) in China. METHODS: A Markov model describing CHB disease progression was constructed to compare the cost-effectiveness of the first-line therapies, considering both satisfactory (HBeAg seroconversion) and optimal (HBsAg seroclearance) treatment goals. We examined the main outcomes, including cumulative lifetime cost per patient, incremental quality-adjusted life years (QALYs), incremental cost-effectiveness ratio and net monetary benefit. Uncertainty analysis was conducted to identify key influential parameters. RESULTS: Compared with the baseline strategy, Peg-IFN had the highest QALY gain for HBeAg-positive (HBeAg+) CHB patients achieving a satisfactory goal and an optimal goal (3.19 and 6.32 respectively), and TDF was the most cost-effective therapy for HBeAg-negative CHB patients ($1418/QALY) achieving a satisfactory goal. Among nucleotide analogues, TAF was the most-effective strategy and had higher acceptability to achieve an optimal goal in the Eastern region of China (under 1 x GDP per capita threshold). CONCLUSIONS: Among nucleotide analogues, TDF was the most cost-effective treatment in China for CHB patients to achieve satisfactory and optimal treatment goals, whereas TAF was cost-effective and more effective in the wealthier region. Peg-IFN was most cost-effective among HBeAg+ CHB patients to achieve both goals, with better clinical outcomes. Our findings also indicate the importance of regular monitoring during and after CHB treatment, and could inform treatment strategies in China and other countries.

Association between antibiotic consumption and colon and rectal cancer development in older individuals: A territory-wide study.

BACKGROUND: Antibiotics may alter colorectal cancer (CRC) risk due to gut dysbiosis. We aimed to study the specific and temporal effects of various antibiotics on CRC development in older individuals. METHODS: This was a territory-wide retrospective cohort study. Subjects aged 60 years and older who did not have CRC diagnosed on screening/diagnostic colonoscopy diagnosed between 2005 and 2013 were recruited. Exclusion criteria were history of CRC, colectomy, inflammatory bowel disease, and CRC diagnosed within 6 months of index colonoscopy. Exposure was use of any antibiotics up to 5 years before colonoscopy. The primary outcomes were CRC diagnosed >6 m after colonoscopy. Covariates were patient demographics, history of colonic polyps/polypectomy, concomitant medication use (NSAIDs, COX-2 inhibitors, aspirin, and statins), and performance of endoscopy centers (colonoscopy volume and polypectomy rate). Stratified analysis was conducted according to nature of antibiotics and location of cancer. RESULTS: Ninety seven thousand one hundred and sixty-two eligible subjects (with 1026 [1.0%] cases of CRC) were identified, 58,704 (60.4%) of whom were exposed to antibiotics before index colonoscopy. Use of antibiotics was associated with a lower risk of cancer in rectum (adjusted hazard ratio [aHR]: 0.64, 95% CI: 0.54-0.76), but a higher risk of cancer in proximal colon (aHR: 1.63, 95%CI: 1.15-2.32). These effects differed as regards the anti-anaerobic/anti-aerobic activity, narrow-/broad-spectrum, and administration route of antibiotics. CONCLUSIONS: Antibiotics had divergent effects on CRC development in older subjects, which varied according to the location of cancer, antibiotic class, and administration route.

Strength and durability of antibody responses to BNT162b2 and CoronaVac.

We studied 2780 adults in Hong Kong who received CoronaVac inactivated virus vaccine (Sinovac) and BNT162b2 mRNA vaccine ("Comirnaty", BioNTech/Fosun Pharma). We compared rates of antibody waning over time using an enzyme-linked immunosorbent assay for spike receptor binding domain and a surrogate virus neutralization test. We found stronger and more durable antibody responses to two doses of the mRNA vaccine, and slightly stronger initial antibody responses to each vaccine in younger adults and women. The weaker and less durable responses following CoronaVac support earlier provision of third doses to persons who previously received two doses of this vaccine.

Cost-Effectiveness of Anti-Epidermal Growth Factor Receptor Therapy Versus Bevacizumab in KRAS Wild-Type (WT), Pan-RAS WT, and Pan-RAS WT Left-Sided Metastatic Colorectal Cancer.

OBJECTIVES: We aimed to compare the economic value of chemotherapy plus anti-epidermal growth factor receptor (anti-EGFR) monoclonal antibody (mAb) against chemotherapy with bevacizumab (Bev, an anti-vascular endothelial growth factor mAb) as first-line treatment in KRAS wild-type (WT), pan-RAS WT and pan-RAS WT left-sided metastatic colorectal cancer (mCRC) patients from the Hong Kong societal perspective. MATERIALS AND METHODS: We developed Markov models and 10-year horizon to estimate costs, quality-adjusted life years (QALYs), and incremental cost-effectiveness ratio (ICER) of chemotherapy plus anti-EGFR therapy against chemotherapy plus Bev in KRAS WT, pan-RAS WT, and pan-RAS WT left-sided mCRC. We considered two times of the local gross domestic product per capita (GDPpc) as the willingness-to-pay (WTP) threshold (2× GDPpc; US$97,832). RESULTS: Adding anti-EGFR mAb to chemotherapy provides additional 0.24 (95% confidence interval [CI] 0.19-0.29), 0.32 (95% CI 0.27-0.37), and 0.57 (95% CI 0.49-0.63) QALY compared to adding Bev in KRAS WT, pan-RAS WT, and left-sided pan-RAS WT mCRC populations respectively. The corresponding ICER is US$106,847 (95% CI 87,806-134,523), US$88,565 (95% CI 75,678-105,871), US$76,537 (95% CI 67,794-87,917) per QALY gained, respectively. CONCLUSIONS: Anti-EGFR therapy is more cost-effective than Bev as a first-line targeted therapy in left-sided pan-RAS WT and pan-RAS WT, with ICER

Risk of malignancies in patients with inflammatory bowel disease who used thiopurines as compared with other indications: a territory-wide study.

AIMS: Thiopurines are believed to increase cancer risks, but data from Asian patients are sparse. We determined the risks of malignancies in thiopurine users with inflammatory bowel disease (IBD) or other indications from Hong Kong. METHODS: All patients who had received thiopurines between 2005 and 2009 in Hong Kong were identified from local electronic healthcare database. Patients were followed from the start date of thiopurines until death or end of study in 2017. We excluded patients with baseline malignancy. Standardized incidence ratios (SIR) and the corresponding 95% confidence intervals (CI) of all malignancies were computed against matched local general population from the cancer registry. Patients in the same diagnosis category but not exposed to thiopurines were included as controls. RESULTS: There were 7452 thiopurines users (median age 47.0 years), including 595 IBD patients, with a median follow-up of 11.2 years. Of them, 684 (9.2%) developed malignancies with an overall SIR of 2.30 (95% CI 2.13-2.48). The SIR in IBD patients who used thiopurines was 2.37 (95% CI 1.71-3.18) as compared with non-users (SIR 1.35, 95% CI 1.05-1.72). Highest risk of malignancies was observed in post-transplant patients (SIR 3.83, 95% CI 3.34-4.35), and lower risks were seen in patients with rheumatological diseases (SIR 1.46, 95% CI 1.02-2.02). CONCLUSION: IBD patients in Hong Kong who used thiopurines had 2.37-fold increase in risk of malignancies than the general population, which was higher than non-users and different from thiopurine users for other indications.

A multilevel analysis of the effects of neighbourhood income inequality on individual self-rated health in Hong Kong.

We examined the effect on self-rated health of neighbourhood-level income inequality in Hong Kong, which has a high and growing Gini coefficient. Data were derived from two population household surveys in 2002 and 2005 of 25,623 and 24,610 non-institutional residents aged 15 or over. We estimated neighbourhood-level Gini coefficients in each of 287 Government Planning Department Tertiary Planning Units. We used multilevel regression analysis to assess the association of neighbourhood income inequality with individual self-perceived health status. After adjustment for both individual- and household-level predictors, there was no association between neighbourhood income inequality, median household income or household-level income and self-rated health. We tested for but did not find any statistical interaction between these three income-related exposures. These findings suggest that neighbourhood income inequality is not an important predictor of individual health status in Hong Kong.

Reporting and guidelines for mendelian randomization analysis: A systematic review of oncological studies.

BACKGROUND: Mendelian randomization (MR) analyses have been increasingly used to seek evidence of causal associations. This systematic review aims at characterizing and evaluating the reporting of MR analyses in oncological studies. METHODS: The PubMed database was searched to identify MR cancer studies until December 31, 2017. Two of the authors independently selected and evaluated reporting quality of the studies. Reporting quality in MR studies before 2016 and in 2016/17 was compared. RESULTS: Cancer studies with MR analyses in 2016 and 2017 accounted for 55.8% of the total number of studies identified. In the 77 eligible articles, 39 (50.6%) did not report subjects' characteristics, 53 (68.8%) did not conduct power estimation, 40 (51.9%) did not state all of the first three MR assumptions (i.e., genetic instrument is associated with exposure, is not associated with confounders, and acts on outcome only through exposure), and 31 (40.3%) did not exclude SNPs that diverged from Hardy-Weinberg equilibrium. More studies estimated power in 2016/2017 than before 2016 (p = 0.028). CONCLUSIONS: Some MR cancer studies did not sufficiently report essential information, posing obstacles for critical appraisal. This study proposes for MR analysis a guideline/checklist for future publications in cancer and other biomedical research.

Clinical prognostic rules for severe acute respiratory syndrome in low- and high-resource settings.

BACKGROUND: An accurate prognostic model for patients with severe acute respiratory syndrome (SARS) could provide a practical clinical decision aid. We developed and validated prognostic rules for both high- and low-resource settings based on data available at the time of admission. METHODS: We analyzed data on all 1755 and 291 patients with SARS in Hong Kong (derivation cohort) and Toronto (validation cohort), respectively, using a multivariable logistic scoring method with internal and external validation. Scores were assigned on the basis of patient history in a basic model, and a full model additionally incorporated radiological and laboratory results. The main outcome measure was death. RESULTS: Predictors for mortality in the basic model included older age, male sex, and the presence of comorbid conditions. Additional predictors in the full model included haziness or infiltrates on chest radiography, less than 95% oxygen saturation on room air, high lactate dehydrogenase level, and high neutrophil and low platelet counts. The basic model had an area under the receiver operating characteristic (ROC) curve of 0.860 in the derivation cohort, which was maintained on external validation with an area under the ROC curve of 0.882. The full model improved discrimination with areas under the ROC curve of 0.877 and 0.892 in the derivation and validation cohorts, respectively. CONCLUSION: The model performs well and could be useful in assessing prognosis for patients who are infected with re-emergent SARS.

Methods for monitoring influenza surveillance data.

BACKGROUND: A variety of Serfling-type statistical algorithms requiring long series of historical data, exclusively from temperate climate zones, have been proposed for automated monitoring of influenza sentinel surveillance data. We evaluated three alternative statistical approaches where alert thresholds are based on recent data in both temperate and subtropical regions. METHODS: We compared time series, regression, and cumulative sum (CUSUM) models on empirical data from Hong Kong and the US using a composite index (range = 0-1) consisting of the key outcomes of sensitivity, specificity, and time to detection (lag). The index was calculated based on alarms generated within the first 2 or 4 weeks of the peak season. RESULTS: We found that the time series model was optimal in the Hong Kong setting, while both the time series and CUSUM models worked equally well on US data. For alarms generated within the first 2 weeks (4 weeks) of the peak season in Hong Kong, the maximum values of the index were: time series 0.77 (0.86); regression 0.75 (0.82); CUSUM 0.56 (0.75). In the US data the maximum values of the index were: time series 0.81 (0.95); regression 0.81 (0.91); CUSUM 0.90 (0.94). CONCLUSIONS: Automated influenza surveillance methods based on short-term data, including time series and CUSUM models, can generate sensitive, specific, and timely alerts, and can offer a useful alternative to Serfling-like methods that rely on long-term, historically based thresholds.

Non-attendance and effective equity of access at four public specialist outpatient centers in Hong Kong.

This study tests whether socio-economic status (SES), at either the individual or ecologic levels, exerts a direct impact on non-attendance or an indirect impact on attendance through longer waiting time for appointments and/or doctor-shopping behavior at four public specialist outpatient centers in Hong Kong. We collected information through three main sources, namely patients' referral letters, telephone interviews with both open- and closed-ended questions (e.g. doctor-shopping data) and hospital administrative databases from a total of 6495 attenders and non-attenders enrolled from July 2000 through October 2001. Individual-level SES was measured by education, occupation and monthly household income. Tertiary planning unit (TPU)-level SES data consisted of proportion unemployed, proportion with tertiary education, median income and Gini coefficient. Direct effects of SES on non-attendance were examined by logistic regression. Indirect contributions mediated through waiting time and doctor-shopping were analyzed by structural equation modeling. We found that SES, at the individual or ecologic level, did not exert a direct effect on non-attendance. Instead, TPU-level SES contributed positively to waiting time (beta=0.06+/-0.03, p=0.048), i.e. worse-off neighborhoods (and those with greater income inequality) had a shorter waiting time. Individual-level SES was also directly associated with the likelihood of doctor-shopping (beta=0.16+/-0.02, p<0.001), i.e. the poor were less likely to doctor-shop. Both waiting time (beta=0.12+/-0.02, p<0.001) and doctor-shopping (beta=0.37+/-0.02, p<0.001) were significantly related to non-attendance. Our findings suggest a highly equitable specialist ambulatory care public system in Hong Kong. Health care resources are appropriately targeted at the socially indigent, and the poor are not discriminated against and pushed to seek alternative sources of care by the system. These results should be confirmed using a prospective design.

The ecology of health care in Hong Kong.

To better understand the distribution of resources and health care consumption patterns in different geo-ethnic and socio-economic settings, we sought to describe the patterns of illness, care-seeking behavior and health services utilization in Hong Kong compared to the US and UK. Data were derived from the 2002 Hong Kong Thematic Household Survey covering 31,762 non-institutional and institutional residents, representing 6,504,255 persons after applying population weights. Of 1000 individuals during a 1-month period, 567 reported symptoms, 512 of whom considered seeking health care. Four hundred and forty persons visited western allopathic medical practitioners, with 372 (84.5%) in primary care and 68 (15.5%) in specialty care. There were 54 visits to traditional Chinese medical practitioners and 16 emergency room episodes. Seven individuals were hospitalized in community hospitals and on average one in 1000 were admitted to a tertiary medical center. Ninety out of the 567 who experienced symptoms undertook self-management strategies, which included over-the-counter western allopathic medications (n=54) or traditional Chinese remedies (n=14) or both (n=2), dietary modification (n=1) and rest (n=15). We have mapped the ecology of health care in Hong Kong. Monthly prevalence estimates were remarkably similar to US figures for hospital-based events, whereas there was evidence of apparent, substantial "over-consumption" of ambulatory, community-based care. Our results also indicate that the local community's care-seeking orientation still very much favors western allopathic medicine over traditional Chinese therapy, at least for acute illness episodes.

A clinical prediction rule for diagnosing severe acute respiratory syndrome in the emergency department.

BACKGROUND: Accurate, objective models of triage for patients with suspected severe acute respiratory syndrome (SARS) could assess risks and improve decisions about isolation and inpatient treatment. OBJECTIVE: To develop and validate a clinical prediction rule for identifying patients with SARS in an emergency department setting. DESIGN: Retrospective analysis using a 2-step coefficient-based multivariable logistic regression scoring method with internal validation by bootstrapping. SETTING: 2 hospitals in Hong Kong. PARTICIPANTS: 1274 consecutive patients from 1 hospital and 1375 consecutive patients from another hospital. MEASUREMENTS: Points were assigned on the basis of history, physical examination, and simple investigations obtained at presentation. The outcome measure was a final diagnosis of SARS, as confirmed by World Health Organization laboratory criteria. RESULTS: Predictors for SARS on the basis of history (step 1) included previous contact with a patient with SARS and the presence of fever, myalgia, and malaise. Age 65 years and older and younger than 18 years and the presence of sputum, abdominal pain, sore throat, and rhinorrhea were inversely related to having SARS. In step 2, haziness or pneumonic consolidation on chest radiographs and low lymphocyte and platelet counts, in addition to a positive contact history and fever were associated with a higher probability of SARS. A high neutrophil count, the extremes of age, and sputum production were associated with a lower probability of SARS. In the derivation sample, the observed incidence of SARS was 4.4% for those assigned to the low-risk group (in steps 1 or 2); in the high-risk group, incidence of SARS was 21.0% for quartile 1, 39.5% for quartile 2, 61.2% for quartile 3, and 79.7% for quartile 4. This prediction rule achieved an optimism-corrected sensitivity of 0.90, a specificity of 0.62, and an area under the receiver-operating characteristic curve of 0.85. LIMITATIONS: The prediction rule may not apply to isolated cases occurring during an interepidemic period. Generalizability of the findings should be confirmed in other SARS-affected countries and should be prospectively validated if SARS returns. CONCLUSIONS: Our findings suggest that a simple model that uses clinical data at the time of presentation to an emergency department during an acute outbreak predicted the incidence of SARS and provided good diagnostic utility.

The epidemiology of severe acute respiratory syndrome in the 2003 Hong Kong epidemic: an analysis of all 1755 patients.

BACKGROUND: As yet, no one has written a comprehensive epidemiologic account of a severe acute respiratory syndrome (SARS) outbreak from an affected country. OBJECTIVE: To provide a comprehensive epidemiologic account of a SARS outbreak from an affected territory. DESIGN: Epidemiologic analysis. SETTING: The 2003 Hong Kong SARS outbreak. PARTICIPANTS: All 1755 cases and 302 deaths. MEASUREMENTS: Sociodemographic characteristics; infection clusters by time, occupation, setting, and workplace; and geospatial relationships were determined. The mean and variance in the time from infection to onset (incubation period) were estimated in a small group of patients with known exposure. The mean and variance in time from onset to admission, from admission to discharge, or from admission to death were calculated. Logistic regression was used to identify important predictors of case fatality. RESULTS: 49.3% of patients were infected in clinics, hospitals, or elderly or nursing homes, and the Amoy Gardens cluster accounted for 18.8% of cases. The ratio of women to men among infected individuals was 5:4. Health care workers accounted for 23.1% of all reported cases. The estimated mean incubation period was 4.6 days (95% CI, 3.8 to 5.8 days). Mean time from symptom onset to hospitalization varied between 2 and 8 days, decreasing over the course of the epidemic. Mean time from onset to death was 23.7 days (CI, 22.0 to 25.3 days), and mean time from onset to discharge was 26.5 days (CI, 25.8 to 27.2 days). Increasing age, male sex, atypical presenting symptoms, presence of comorbid conditions, and high lactate dehydrogenase level on admission were associated with a greater risk for death. LIMITATIONS: Estimates of the incubation period relied on statistical assumptions because few patients had known exposure times. Temporal changes in case management as the epidemic progressed, unavailable treatment information, and several potentially important factors that could not be thoroughly analyzed because of the limited sample size complicate interpretation of factors related to case fatality. CONCLUSIONS: This analysis of the complete data on the 2003 SARS epidemic in Hong Kong has revealed key epidemiologic features of the epidemic as it evolved.