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77 result(s) for "Chan, Chi Kuen"
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Prevention of Acute Myocardial Infarction and Stroke among Elderly Persons by Dual Pneumococcal and Influenza Vaccination: A Prospective Cohort Study
Background. DespiteWorld Health Organization recommendations, the rate of 23-valent pneumococcal (PPV) and influenza (TIV) vaccination among elderly persons in Hong Kong, China, is exceptionally low because of doubts about effectiveness of vaccination. The efficacy of dual vaccination remains unknown. Methods. From 3 December 2007 to 30 June 2008, we conducted a prospective cohort study by recruiting outpatients aged ⩾65 years with chronic illness to participate in a PPV and TIV vaccination program. All were observed until 31 March 2009. The outcome of subjects, including the rates of death, hospitalization, pneumonia, ischemic stroke, acute myocardial infarction, and coronary and intensive care admissions, were determined. Results. Of the 36,636 subjects recruited, 7292 received both PPV and TIV, 2076 received TIV vaccine alone, 1875 received PPV alone, and 25,393 were unvaccinated, with a duration of follow-up of 45,834 person-years. Baseline characteristics were well matched between the groups, except that there were fewer male patients in the PPV and TIV group and fewer cases of comorbid chronic obstructive pulmonary disease among unvaccinated persons. At week 64 from commencement of the study, dual-vaccinees experienced fewer deaths (hazard ratio [HR], 0.65; 95% confidence interval [CI], 0.55–0.77]; P <.001) and fewer cases of pneumonia (HR, 0.57; 95% CI, 0.51–0.64; P<.001), ischemic stroke (HR, 0.67; 95% CI, 0.54–0.83; P<.001), and acute myocardial infarction (HR, 0.52; 95% CI, 0.38–0.71; P<.001), compared with unvaccinated subjects. Dual vaccination resulted in fewer coronary (HR, 0.59; 95% CI, 0.44–0.79; P<.001) and intensive care admissions (HR, 0.45; 95% CI, 0.22–0.94; P = .03), compared with among unvaccinated subjects. Conclusions. Dual vaccination with PPV and TIV is effective in protecting elderly persons with chronic illness from developing complications from respiratory, cardiovascular, and cerebrovascular diseases, thereby reducing hospitalization, coronary or intensive care admissions, and death.
Association of smoking cessation with airflow obstruction in workers with silicosis: A cohort study
Studies in general population reported a positive association between tobacco smoking and airflow obstruction (AFO), a hallmark of chronic obstructive pulmonary disease (COPD). However, this attempt was less addressed in silica dust-exposed workers. This retrospective cohort study consisted of 4481 silicotic workers attending the Pneumoconiosis Clinic during 1981-2019. The lifelong work history and smoking habits of these workers were extracted from medical records. Spirometry was carried out at the diagnosis of silicosis (n = 4177) and reperformed after an average of 9.4 years of follow-up (n = 2648). AFO was defined as forced expiratory volume in one second (FEV1)/force vital capacity (FVC) less than lower limit of normal (LLN). The association of AFO with smoking status was determined using multivariate logistics regression, and the effect of smoking cessation on the development of AFO was evaluated Cox regression. Smoking was significantly associated with AFO (current smokers: OR = 1.92, 95% CI 1.51-2.44; former smokers: OR = 2.09, 95% CI 1.65-2.66). The risk of AFO significantly increased in the first 3 years of quitting smoking (OR = 1.23, 95% CI 1.02-1.47) but decreased afterwards with increasing years of cessation. Smoking cessation reduced the risk of developing AFO no matter before or after the confirmation of silicosis (pre-silicosis cessation: HR = 0.58, 95% CI 0.46-0.74; post-silicosis cessation: HR = 0.62, 95% CI 0.48-0.79). Smoking cessation significantly reduced the risk of AFO in the workers with silicosis, although the health benefit was not observed until 3 years of abstinence. These findings highlight the importance of early and long-term smoking cessation among silicotic or silica dust-exposed workers.
Association of circadian rhythm with mild cognitive impairment among male pneumoconiosis workers in Hong Kong: a cross-sectional study
Weakened circadian activity rhythms (CARs) were associated with mild cognitive impairment (MCI) in the general population. However, it remains unclear among pneumoconiosis patients. We aimed to address this knowledge gap. This cross-sectional study comprised 186 male pneumoconiosis patients (71.3 ± 7.8 years) and 208 healthy community men. Actigraphy was used to determine CARs parameters (percent rhythm, amplitude, MESOR, and acrophase). Values below the corresponding medians of the CARs parameters represented weakened CARs. The Cantonese version of Mini-Mental State Examination (CMMSE) was used to assess cognitive function, MCI, and the composite outcome of MCI plus cognitive impairment. Compared with the community referents, pneumoconiosis patients had worse cognition and dampened CARs. Compared with the community referents or pneumoconiosis patients with robust circadian rhythm, pneumoconiosis patients with weakened circadian rhythm were consistently associated with increased risk of MCI and the composite outcome. However, significant association was only observed between MESOR and the composite outcome (adjusted OR = 1.99, 95%: 1.04–3.81). A delayed phase of CARs was insignificantly associated with MCI and the composite outcome. Our findings showed that weakened CARs were associated with worse cognitive function among male pneumoconiosis workers. Intervention in improving CARs may mitigate cognitive deterioration in male pneumoconiosis workers.
Seasonality of tuberculosis in intermediate endemicity setting dominated by reactivation diseases in Hong Kong
Summer-spring predominance of tuberculosis (TB) has been widely reported. The relative contributions of exogenous recent infection versus endogenous reactivation to such seasonality remains poorly understood. Monthly TB notifications data between 2005 and 2017 in Hong Kong involving 64,386 cases (41% aged ≥ 65; male-to-female ratio 1.74:1) were examined for the timing, amplitude, and predictability of variation of seasonality. The observed seasonal variabilities were correlated with demographics and clinical presentations, using wavelet analysis coupled with dynamic generalised linear regression models. Overall, TB notifications peaked annually in June and July. No significant annual seasonality was demonstrated for children aged ≤ 14 irrespective of gender. The strongest seasonality was detected in the elderly (≥ 65) among males, while seasonal pattern was more prominent in the middle-aged (45–64) and adults (30–44) among females. The stronger TB seasonality among older adults in Hong Kong suggested that the pattern has been contributed largely by reactivation diseases precipitated by defective immunity whereas seasonal variation of recent infection was uncommon.
Changes in physical activity and rest-activity circadian rhythm among Hong Kong community aged population before and during COVID-19
Background This study aims to determine the changes in physical activity and actigraphy-measured rest-activity circadian rhythm among Hong Kong community aged population before and during the outbreak of COVID-19. Methods This is a three repeated measure population-based cross-sectional study. We recruited community older men aged >  60 years in three periods of the COVID-19 outbreak in Hong Kong, i.e., before the COVID-19 outbreak (2 July 2019–8 January 2020), between the 2nd and 3rd waves of COVID-19 (23 June 2020–9 July 2020), and during the 3rd wave of COVID-19 (15 September 2020–29 September 2020). Participants reported detailed information on their physical activity habits using the International Physical Activity Questionnaire and wore actigraphs continuously for 7 days (168 h). The actigraph data were then transferred to four rest-activity circadian rhythm parameters: midline statistic of rhythm (MESOR), amplitude, acrophase and percent rhythm. Multivariate logistic regression was performed to estimate the association of period effect of COVID-19 on physical activity and rest-activity circadian rhythm parameters. Results Among the 242 community older men, 106 (43.8%) of them were recruited before the COVID-19 outbreak, 66 (27.3%) were recruited between the 2nd and 3rd waves of COVID-19, and 70 (28.9%) were recruited during the late phase of the 3rd wave of COVID-19. Compared with those recruited before COVID-19, participants recruited between the 2nd and 3rd waves of COVID-19 had lower physical activity (adjusted odds ratio (AOR) = 2.03, 95% confidence interval (95%CI) =1.05–3.93), MESOR (AOR = 2.05, 95%CI = 1.01–4.18), and amplitude (AOR = 1.91, 95%CI = 0.95–3.83). There was no difference in physical activity or circadian rhythm parameters between subjects recruited before and during the late phase of the 3rd wave. Conclusions This study found that the effect of COVID-19 on physical activity and rest-activity circadian rhythm for the community people may be short-term, indicating strong resilience of the community population. Although maintaining physical activity are encouraged for the older adults to sustain good health, a rebound in their physical activity may be a sign for the next wave of outbreak if insufficient social distancing and population protection are facilitated.
Association of spirometric restriction with mortality in the silicotics: a cohort study
Background Restrictive spirometry pattern (RSP), defined as reduced forced vital capacity (FVC) in absence of airflow obstruction (AFO), is associated with increased risk of mortality in general population. However, evidence in the patients with silicosis is limited. This study was aimed to investigate the relationship between RSP and the risk of death in a silicotic cohort. Method This retrospective cohort study used data from the Pneumoconiosis Clinic, Hong Kong Department of Health that containing 4315 patients aged 18–80 years and diagnosed with silicosis during 1981–2019, with a follow-up till 31 December 2019. Spirometry was carried out at the diagnostic examination of silicosis. Lung function categories were classified as normal spirometry (FEV 1 /FVC ≥ 0.7, FVC ≥ 80% predicted), RSP only (FEV 1 /FVC ≥ 0.7, FVC < 80% predicted), AFO only (FEV1/FVC < 0.7, FVC ≥ 80% predicted), and RSP&AFO mixed (FEV 1 /FVC < 0.7, FVC < 80% predicted). The hazard ratio (HR) and 95% confidence intervals (95% CI) were computed using a Cox proportional hazards model adjusting for age, body mass index, history of tuberculosis, smoking status, pack-years, and radiographic characteristics of silicotic nodules. Results Among the 4315 patients enrolled in the study, the prevalence of RSP was 24.1% (n = 1038), including 11.0% (n = 473) with RSP only and 13.1% (n = 565) with mixed RSP and AFO. During the follow-up period, a total of 2399 (55.6%) deaths were observed. Compared with the silicotics with normal spirometry, those with RSP only had significantly increased risk of all-cause mortality (HR = 1.63, 95% CI 1.44–1.85) and respiratory-related mortality (HR = 1.56, 95% CI 1.31–1.85). Notably, a higher risk of mortality was observed in silicotics with mixed ventilatory defects of both RSP and AFO (all-cause mortality: HR = 2.22, 95% CI 1.95–2.52; respiratory-related mortality: HR = 2.59, 95% CI 2.18–3.07) than in those with RSP only. Conclusion RSP is significantly associated with increased risk of all-cause and respiratory-related mortality in the silicotics, and patients with mixed restrictive and obstructive ventilatory defect have higher risk of mortality than those with single RSP or AFO. These findings emphasize the importance of recognizing RSP in the occupational settings, especially for the silicotic patients with mixed ventilatory defect.
Comparative roles of levofloxacin and ofloxacin in the treatment of multidrug-resistant tuberculosis: Preliminary results of a retrospective study from Hong Kong
To compare levofloxacin and ofloxacin in the treatment of multidrug-resistant tuberculosis (MDR-TB). A retrospective analysis of 106 patients with MDR-TB (February 1990 through December 2000) receiving directly observed therapy with fluoroquinolone and accompanying drugs, which mainly included aminoglycosides, cycloserine, ethionamide/prothionamide, and pyrazinamide, was performed. Clinical data from 99 suitable patients were subjected to univariate analysis, stratification, and multiple logistic regression to compare the roles of levofloxacin and ofloxacin in multidrug regimens. Forty patients received 612.5 +/- 79.0 mg qd levofloxacin (mean +/- SD), and 59 patients received 628.8 +/- 101.8 mg qd ofloxacin together with similar active second-line drugs for similar durations. The times to sputum smear (both 1.8 months) and culture conversion (both 2.1 months) were equivalent. Adverse reactions occurred at similar rates (10.0% vs 11.9%). The combined treatment success rate was 83.8%, being higher among ofloxacin-susceptible than ofloxacin-resistant cases (90.5% vs 64.0%, p < 0.01). The success rates for the levofloxacin group were 90.0% (overall), 96.2% (ofloxacin-susceptible cases), and 78.6% (ofloxacin-resistant cases) in comparison with 79.7%, 87.5%, and 45.5%, respectively, for the ofloxacin group (Mantel-Haenszel common odds ratio estimate, 4.0; p < 0.05). Bacillary susceptibility to ofloxacin, good adherence, radiographic extent of one lung or less, and use of levofloxacin were independent predictors of favorable outcome (odds ratios, 7.6 to 21.3). One patient each from both groups relapsed. Levofloxacin was found to be more efficacious than ofloxacin when incorporated into multidrug regimens used for treatment of MDR-TB.
Improving outpatient phlebotomy service efficiency and patient experience using discrete-event simulation
Purpose – The purpose of this paper is to present a simulation modeling application to reconfigure the outpatient phlebotomy service of an acute regional and teaching hospital in Hong Kong, with an aim to improve service efficiency, shorten patient queuing time and enhance workforce utilization. Design/methodology/approach – The system was modeled as an inhomogeneous Poisson process and a discrete-event simulation model was developed to simulate the current setting, and to evaluate how various performance metrics would change if switched from a decentralized to a centralized model. Variations were then made to the model to test different workforce arrangements for the centralized service, so that managers could decide on the service’s final configuration via an evidence-based and data-driven approach. Findings – This paper provides empirical insights about the relationship between staffing arrangement and system performance via a detailed scenario analysis. One particular staffing scenario was chosen by manages as it was considered to strike the best balance between performance and workforce scheduled. The resulting centralized phlebotomy service was successfully commissioned. Practical implications – This paper demonstrates how analytics could be used for operational planning at the hospital level. The authors show that a transparent and evidence-based scenario analysis, made available through analytics and simulation, greatly facilitates management and clinical stakeholders to arrive at the ideal service configuration. Originality/value – The authors provide a robust method in evaluating the relationship between workforce investment, queuing reduction and workforce utilization, which is crucial for managers when deciding the delivery model for any outpatient-related service.
Outcomes of Patients With Multidrug-Resistant Pulmonary Tuberculosis Treated With Ofloxacin/Levofloxacin-Containing Regimens
To analyze outcomes of patients with multidrug-resistant tuberculosis (MDR-TB) treated with ofloxacin/levofloxacin-containing regimens. From February 1990 through June 1997, 63 MDR-TB patients (with bacillary resistance to at least isoniazid and rifampin in vitro) were analyzed retrospectively. Twenty-two patients (34.9%) had had no previous antituberculosis chemotherapy. Each patient received either ofloxacin (53) or levofloxacin (10) even though 13 patients had bacilli resistant to ofloxacin in vitro. The other accompanying drugs mainly included aminoglycosides, cycloserine, ethionamide/prothionamide, and pyrazinamide. Sputum smear and culture examinations for acid-fast bacilli (AFB) were performed monthly for the initial 6 months and then at 2- to 3-month intervals until the end of treatment. Comparison was made between clinical successes and failures using univariate and multiple logistic regression analyses for the following variables: age, sex, presence of cavitation, extent of disease, sputum smear positivity, in vitro resistance to ofloxacin, in vitro resistance to streptomycin and/or ethambutol, treatment adherence, and the number of drugs per regimen. Fifty-one patients (81.0%) were cured, nine patients (14.3%) failed, and three patients (4.7%) died. For the entire group, the mean duration of treatment was 14.0 months, and the mean number of drugs was 4.7. Mean durations of chemotherapy in successful and failed patients were 14.5 and 14.2 months, respectively. Mean time for sputum smear and culture conversions were 1.7 and 2.1 months, respectively. Only cavitation, resistance to ofloxacin, and poor adherence were found to be variables independently associated with adverse outcomes (p < 0.05; odds ratios = 15.9, 13.5, 12.8, respectively). Negative sputum cultures after 2 and 3 months of therapy were 100% predictive of cure. Positive sputum cultures after 2 and 3 months were 52.3% and 84.6% predictive of failure, respectively. One patient (2.1%) relapsed after apparent cure. Twenty-five patients experienced adverse drug reactions, but only 12 of them needed drug modifications. Most MDR-TB patients can be treated effectively with ofloxacin/levofloxacin-containing regimens. Presence of cavitation, resistance to ofloxacin in vitro, and poor adherence to therapy portend treatment failure. Monitoring monthly sputum culture for AFB in the initial months of chemotherapy helps predict clinical outcomes.
Combining tuberculin skin test with follow-on interferon gamma release assay markedly improves screening of household contacts
IntroductionIn Hong Kong, tuberculin skin test (TST) with a 15 mm cut-off was used at 0 and 3 months for contact screening, but half of future tuberculosis cases might be missed. Follow-on interferon-gamma release assay (IGRA) was added for those with tuberculin reaction of 5–14 mm in a pilot programme.MethodsThis was a prospective cohort study. All household contacts of smear-positive tuberculosis aged 12–64 registered in Hong Kong Tuberculosis and Chest Service from 1 July 2018 to 30 June 2022 were prospectively tracked through medical records and the territory-wide tuberculosis notification registry for active tuberculosis till 31 December 2022.ResultsAmong untreated contacts with tuberculin reaction of 5–14 mm in either the initial test or second test at 3 months, the tuberculosis rate among those with a follow-on reactive IGRA was significantly higher than those with a non-reactive IGRA (12.44 vs 0.75 per 1000 person-years, relative risk: 16.52, p=0.003). After adjustment for the efficacy of preventive treatment among all treated cases, the estimated proportions of tuberculosis cases captured by the pilot programme criterion of TST≥15 mm/TST 5–14 mm and IGRA reactive/TST conversion were similar to those captured by TST cut-offs of 5 mm or 10 mm, despite consistently lower positive rates. With an overall test-positive rate of 54.5%, the pilot programme captured 95.8% of estimated future tuberculosis cases at a relative risk between test-positive and test-negative cases of 19.ConclusionCombining TST with follow-on IGRA for those with tuberculin reaction of 5–14 mm markedly improves screening of household contacts in an intermediate burden setting.