Biomedical subjects

Andy H Lee

Publications and source records attributed to Andy H Lee.

At least 55 records · Page 3Linked to original sources

PubMed2004

Recurrent ischaemic stroke hospitalisations: a retrospective cohort study using Western Australia linked patient records.

A retrospective cohort study was undertaken to determine factors that affect the frequency of recurrent ischaemic stroke hospitalisations. Linked hospitalisation records of all Western Australian patients admitted for ischaemic stroke for the first time during July-December 1995 were retrieved until December 2000 to derive the number of readmissions for recurrent strokes, patient medical conditions and co-morbidities at the index episode. A negative binomial regression model adjusting for inter-hospital variations was used to determine the prognostic factors influencing recurrent stroke hospitalisations. Of the 678 patients in the cohort, 124 (18.3%) experienced repeated episodes of ischaemic stroke. Rural residence and carotid endarterectomy procedure were positively associated with the recurrence frequency, the adjusted incidence rate ratio being 1.66 (95% CI: 1.17-2.36) and 3.96 (95% CI: 2.30-6.82), respectively. Rural patients contributed to 18% of the patients in the cohort yet they accounted for 27% of those sustaining repeated episodes of stroke. Readmissions were also related to the presence of diabetes at the index episode. The effect of diabetes, with adjusted incidence rate ratio 1.35 (95% CI: 1.01-1.79), was only evident after accounting for within hospital correlations. These findings have implications on hospital resource planning and secondary preventive strategies to reduce the burden of stroke.

Aged↗

PubMed2004

Ischemic stroke hospital stay and discharge destination.

PURPOSE: Stroke hospitalizations are among the most expensive, with a mean length of stay (LOS) higher than other hospitalizations. This retrospective study assesses factors influencing ischemic stroke LOS taking into consideration the discharge destination of patients. METHODS: Linked hospital separation records between July 1995 and December 1999 were extracted to determine the first admission for ischemic stroke in Western Australia. Multiple hospitalization records for the same patient were screened to obtain the total duration of hospitalization. Demographic characteristics, hospital type, and medical history of patients were also retrieved. In the presence of censoring and without prior assumption on the time-to-discharge distribution, the Cox's proportional hazards model was used to assess the factors affecting LOS. RESULTS: During the study period, 6469 patients with a first-ever admission for ischemic stroke were identified, with average LOS being 28 days (95% CI, 26-30 days). Hospital stays were significantly longer for females and patients directly admitted to hospitals maintaining a specialist stroke unit, whereas patients residing in rural areas had shorter stays. CONCLUSIONS: The impact of stroke severity and placement in nursing homes after discharge need to be understood to manage LOS and the cost of acute care. Accurate diagnosis upon initial presentation would benefit both the efficiency of hospitals and the outcomes of rural ischemic stroke patients.

Age Distribution↗

PubMed2004

Utilization of delivery services at the primary health care level in rural Vietnam.

The objective of this study is to investigate factors that influence the utilization of delivery services at the primary health care level in rural Vietnam. A quantitative survey was conducted amongst 200 women who had given birth within the past 3 months. Focus group discussions and in-depth-interviews were then undertaken using the attitudes--social influence--self-efficacy model to obtain complementary information on the delivery decision. The results show that client-perceived quality of services and socio-cultural and economic factors, rather than geographical access, can affect the utilization of delivery services. It is therefore important to improve the cost-efficiency of the health care network, and delivery services should be provided in a client-oriented manner taking into account economic, social and cultural factors.

Adult↗

PubMed2004

Reproductive and dietary risk factors for epithelial ovarian cancer in China.

OBJECTIVE: A case-control study was conducted to investigate the effects of reproductive and dietary risk factors on ovarian cancer risk in China. METHODS: Cases were 254 patients with histologically confirmed epithelial ovarian cancer. Controls were 652 women without neoplasm and long-term dietary modifications. Information was collected using a structured questionnaire on sociodemographic and reproductive characteristics, diet, medical and family cancer history. The risks of ovarian cancer were assessed by multivariate logistic regression analysis. RESULTS: The adjusted odds ratios (OR) for women having at least two full-term pregnancies, two or more incomplete pregnancies, and first full-term pregnancy at 21-25 years of age were 0.45 (95% CI 0.3-0.8), 0.56 (95% CI 0.4-0.8), and 0.40 (95% CI 0.2-0.8), respectively, compared with nulliparity. The OR of ever lactation was 0.50 (95% CI 0.3-0.8) and oral contraceptive was 0.48 (95% CI 0.3-0.7), while postmenopausal women appeared to have an increased risk with OR 1.48 (95% CI 1.0-2.3). For the highest versus the lowest quartile intakes of nutrients, the OR were 2.17 (95% CI 1.3-3.8) for fat, 0.36 (95% CI 0.2-0.6) for fibre, 0.26 (95% CI 0.2-0.5) for carotene, 1.59 (95% CI 0.9-2.7) for retinol, 0.31 (95% CI 0.2-0.5) for vitamin C, and 0.41 (95% CI 0.2-0.7) for vitamin E, with significant dose-response relationships. CONCLUSION: It is evident that full-term and incomplete pregnancies, lactation, and oral contraceptive use can reduce the ovarian cancer risk. Moreover, consumption of foods low in fat but high in fibre, carotene and vitamins appears to be protective against ovarian cancer in Chinese women.

Adult↗

PubMed2004

Modeling zero-inflated count series with application to occupational health.

A zero-inflated Poisson mixed autoregression model is presented for analyzing time series of count events with excess zeros. The model is motivated by the evaluation of a participatory ergonomics intervention intended to reduce manual handling workplace injuries over a specified time period. Random effects are introduced into the linear predictor of the model to account for serial correlation between successive observations. Parameter estimation is achieved by maximizing an appropriate log-likelihood function to obtain approximate residual maximum likelihood estimates. The method enables the evaluation of occupational intervention using population level aggregated count data series containing extra zeros.

Occupational Health↗

PubMed2004

Recurrent gastroenteritis among infants in Western Australia: a seven-year hospital-based cohort study.

PURPOSE: To investigate factors that affect the frequency of recurrent gastroenteritis among infants in Western Australia (WA). METHODS: A 7-year retrospective cohort study was undertaken on all infants born in 1995 who were admitted for gastroenteritis during their first year of life (n=514). Linked hospitalization records of the cohort were retrieved to derive the number of readmissions, microbiologic diagnoses, patient demographics, and co-morbidities at the index episode. A negative binomial regression model adjusting for inter-hospital variations was used to determine the prognostic factors influencing recurrent gastroenteritis. RESULTS: Diarrhea with no specific etiology accounted for 54.7% of the cases presented at index admission and 55.8% of the total 676 admissions for the cohort. Of the 514 infants, 119 (23%) experienced repeated episodes of gastroenteritis. The lowest proportion of recurrences was 15.4% for patients initially admitted for bacterial or viral diarrhea. Over 85% of the recurrences from either bacterial and viral diarrhea or etiology unspecified were readmitted under the same category. Aboriginality and dehydration were significantly associated with the recurrence frequency, the adjusted incidence rate ratio being 2.86 (95% CI, 1.92-4.26) and 0.66 (95% CI, 0.49-0.88), respectively. Aboriginal infants contributed to 58% of those patients in the cohort who sustained repeated episodes of gastroenteritis. The proportion of patients with the recurrent disease was also significantly higher for Aboriginals (39%) than for non-Aboriginals (15%). The effect of dehydration was evident after accounting for within hospital correlations. CONCLUSIONS: Hospitalizations for recurrent gastroenteritis were more frequent among Aboriginal children than non-Aboriginal children in WA. Readmissions were also related to the presence of dehydration at the index episode. These findings have implications for preventive strategies to reduce the burden of gastroenteritis.

Cohort Studies↗

PubMed2004

Sedentary behaviours and epithelial ovarian cancer risk.

OBJECTIVE: To investigate the effects of sedentary behaviours on the risk of epithelial ovarian cancer. METHODS: A case-control study was conducted in China during 1999-2000. Cases were 254 patients with histologically confirmed epithelial ovary cancer. The 652 controls comprised 340 hospital visitors, 261 non-neoplasm hospital outpatients, and 51 women recruited from the community. The daily sitting duration in both occupational- and leisure-time was measured using a validated questionnaire. The risks of ovarian cancer were assessed using multivariate logistic regression analysis accounting for demographic characteristics, body mass index, familial factors, hormonal status, family ovarian cancer history, physical activity (as weekly metabolic equivalent tasks), and total energy intake. RESULTS: Prolonged sitting duration was associated with an increase in ovarian cancer risk. The odds ratios were, respectively, 1.96 (95% confidence interval (CI): 1.2-3.2) with a significant trend (p = 0.007), 3.39 (95% CI: 1.0-11.5), and 1.77 (95% CI: 1.0-3.1) for high level versus low level of sitting at work, sitting while watching television and total sitting duration. CONCLUSION: Sedentary behaviours were associated with an increase in epithelial ovarian cancer risk.

Case-Control Studies↗

PubMed2004

Demographic patterns of emergency presentations to Northern Territory public hospitals.

This study investigates demographic patterns of emergency presentations to Northern Territory (NT) public hospitals over the past five years with respect to population changes, Aboriginality and age of patients. Retrospective analysis was undertaken on the 1996-2001 data extracted from the NT Module of Caresys and the Hospital Morbidity Data System. There was a 4.6% decrease in total presentations to the five public hospitals but a 9.4% growth in the population during the study period. Substantial differences in emergency presentation patterns were found between Aboriginal and non-Aboriginal patients. There were more Aboriginal presentations than non-Aboriginal presentations for all age groups except for 5 to 19 years and 70 to 74 years. Analysis based on the national triage scale showed the higher needs of older adults with the 60 or over age group accounting for the majority of presentations, and Aboriginal presentation rates exceeded the non-Aboriginal presentation rates in most triage categories. Re-attendance within seven days at the emergency departments occurred predominantly among Aboriginal patients regardless of age group. The analysis has highlighted several emerging demographic patterns. The issue of non-urgent visits by Aboriginal patients occupying a large portion of the emergency department utilisation also needs to be addressed.

Demography↗

PubMed2004

Breast-feeding initiation and exclusive breast-feeding in rural Vietnam.

OBJECTIVE: To investigate the initiation of breast-feeding and exclusive breast-feeding within the first week after delivery for women in rural Vietnam. DESIGN: An interviewer-administered survey was conducted on a sample of rural women who gave birth during August-October 2002. SETTING: Quang Xuong District, Thanh Hoa Province of Vietnam. SUBJECTS: Four hundred and sixty-three women participated in the study, of whom 181 delivered at the district hospital (39.1%), 229 at a commune health centre (49.5%) and 53 at home attended by a traditional birth attendant (11.4%). RESULTS: Although the initiation and exclusive breast-feeding rates were relatively high at 98.3% and 83.6% respectively, the premature introduction of complementary food was a great concern. Logistic regression analysis showed that, together with socio-cultural determinants such as feeding preferences of the husband and maternal grandmother, feeding practices of friends, factors relating to delivery methods, delivery locations and health problems could influence the initiation rate and breast-feeding patterns. CONCLUSIONS: To promote breast-feeding practices of rural mothers, health education on breast-feeding should take into account local socio-cultural features in addition to improving the counselling skills of health workers.

Adult↗

PubMed2004

Measuring client-perceived quality of maternity services in rural Vietnam.

OBJECTIVE: To examine the feasibility, reliability and validity of a 20-item scale for measuring perceived quality of maternity services provided at commune health centres in rural Vietnam. DESIGN: A survey of 200 women who gave birth in July-August 2000 and 196 pregnant women in 34 communes in Quang Xuong District, Thanh Hoa Province, Vietnam. MAIN OUTCOME MEASURES: Inter-rater reliability, internal consistency and factor structure of the scale were examined. The associations between perceived quality and client characteristics were also investigated. RESULTS: The instrument had relatively good inter-rater reliability and internal consistency. Except for two items: 'good clinical examination' and 'adequacy of health workers for women's health', the scale exhibited good agreement between the two raters, with kappa values ranging from 0.54 to 0.84. The Cronbach's alpha coefficients for the dimensions 'health care delivery', 'health facility', 'interpersonal aspects of care' and 'access to services' were 0.72, 0.64, 0.72 and 0.33, respectively. Respondents were positive on items related to the dimensions 'interpersonal aspects of care' and 'access to services', but negative on the dimensions 'health care delivery' and 'health facility'. The maternity status of clients was found to influence the perceived quality of maternity services. CONCLUSIONS: The feasibility, reliability and validity of the instrument were established in the context of rural Vietnam. Its application in evaluating other health care programmes should be an important follow-up action for the Vietnamese government.

Community Health Centers↗

PubMed2004

The changing role of the emergency department in the Northern Territory: a Delphi study.

OBJECTIVE: To explore the changing role of EDs in Northern Territory hospitals. METHODS: A two-round Delphi study was undertaken by recruiting a panel of health professionals from the EDs of the five Northern Territory public hospitals. Participants in round one were asked to list changes they have encountered and how these changes have affected health service delivery, as well as five factors that were responsible for the changes. During the second round they prioritized the factors identified in order of importance. RESULTS: Twenty-four ED staff returned their questionnaire. Global changes identified were more verbal/physical abuse from patients, followed by increase in acuity of patient presentations. The most important factor perceived as responsible for the changes was budget cuts, resulting in fewer inpatient beds, an increase in access block and sicker patients being discharged too early. CONCLUSION: The Delphi evaluation provided insights into the problems facing the ED from the staff perspective and offered some suggestions to deal with the emerging issues.

Adult↗

PubMed2004

Soy and isoflavone intake are associated with reduced risk of ovarian cancer in southeast china.

To investigate whether intake of soy and isoflavones has an inverse association with ovarian cancer risk, a case-control study was conducted in Hangzhou, China. Cases were 254 patients with histologically confirmed epithelial ovarian cancer. The 652 controls comprised 340 hospital visitors, 261 non-neoplastic hospital outpatients, and 51 women recruited from the community. Habitual dietary intakes including 9 soy foods were measured by face-to-face interview using a validated and reliable food-frequency questionnaire. Unconditional logistic regression analyses were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) accounting for age, demographic characteristics, hormonal factors, and total energy intake. Intake of soy and isoflavones was inversely related to the risk of ovarian cancer. Compared with the highest versus the lowest quartile intake, the ORs were 0.50 (95% CI = 0.31-0.82) for total soy foods and 0.51 (95% CI = 0.31-0.85) for isoflavones. Among subgroups of soy foods and isoflavones, the ORs for soybeans, bean curd, daidzein, genistein, and glycitein were 0.35 (95% CI = 0.22-0.58), 0.49 (95% CI = 0.29-0.81), 0.52 (95% CI = 0.31-0.87), 0.50 (95% CI = 0.30-0.84), and 0.59 (95% CI = 0.35-0.97), respectively.

Adult↗

PubMed2003

Factors influencing survival after stroke in Western Australia.

OBJECTIVE: To determine the factors influencing survival among patients admitted to Western Australian hospitals for the first time with stroke or transient ischaemic attack (TIA). DESIGN, SETTING AND PATIENTS: Linked hospitalisation and death records of 7784 patients admitted to hospital for first-ever stroke or TIA between July 1995 and December 1998 were retrieved retrospectively to determine survival; effects of risk factors on death due to stroke were assessed using the Cox proportional hazards regression model. MAIN OUTCOME MEASURES: All-cause stroke survival; short- and long-term stroke survival probabilities. RESULTS: Survival at 28 days was lowest for haemorrhagic stroke. However, following the first month after admission survival after haemorrhagic stroke was similar to, if not higher than, after ischaemic stroke. Among all patients, significant predictors of death were age (all subtypes of stroke), atrial fibrillation (intracerebral haemorrhage and ischaemic stroke), other cardiac conditions (ischaemic stroke and TIA), and sex and diabetes (TIA). Further predictors of death were residence in rural or remote areas (ischaemic stroke), and Aboriginality (TIA). Among 28-day survivors of ischaemic stroke, additional predictors of death were sex, diabetes and urinary incontinence still present 7 days after admission. CONCLUSION: Use of linked hospitalisation and death data allowed us to increase the scope and size of our study compared with previous studies of survival after stroke and TIA in WA. We confirmed the importance of type of stroke, age and comorbidities to this survival, and found that Aboriginality and place of residence are also important.

Aged↗

PubMed2003

Physical activity and epithelial ovarian cancer risk: a case-control study in China.

A case-control study was conducted in China during 1999-2000 to investigate the effects of intensity and duration of physical activity on the risk of epithelial ovarian cancer. Cases were 254 patients with histologically confirmed epithelial ovarian cancer. The 652 controls comprised 340 hospital visitors, 261 non-neoplasm hospital outpatients and 51 women recruited from the community. Physical activity was measured by a validated questionnaire. The risks of ovarian cancer were assessed using multivariate logistic regression analysis accounting for age, demographic, lifestyle and familial factors, hormonal status, family ovarian cancer history and total energy intake. The study found that increasing total physical activity was associated with a lower ovarian cancer risk among Chinese women. The odds ratio was 0.54 (95% CI 0.34-0.87) for high vs. low levels of total weekly metabolic equivalent tasks. Ovarian cancer risk tended to decline with increasing duration of strenuous sports and frequency of activity-induced sweating among pre-menopausal women, with adjusted OR 0.13 (95% CI 0.03-0.64) and 0.45 (95% CI 0.24-0.85), respectively. Increasing duration of moderate activity in post-menopausal women also appeared to be protective against ovarian cancer, with adjusted OR 0.36 (95% CI 0.18-0.73).

Aged↗

PubMed2003

Truncated negative binomial mixed regression modelling of ischaemic stroke hospitalizations.

A zero-truncated negative binomial mixed regression model is presented to analyse overdispersed positive count data. The study is motivated by the determination of pertinent risk factors associated with ischaemic stroke hospitalizations. Random effects are incorporated in the linear predictor to adjust for inter-hospital variations and the dependency of clustered observations using the generalized linear mixed model approach. The method assists hospital administrators and clinicians to estimate the number of subsequent readmissions based on characteristics of the patient at the index stroke. The findings have important implications on resource usage, rehabilitation planning and management of acute stroke care.

Binomial Distribution↗

PubMed2003

Using a driving simulator to identify older drivers at inflated risk of motor vehicle crashes.

PROBLEM: To develop appropriate assessment criteria to measure the performance of older drivers using an interactive PC-based driving simulator, and to determine which measures were associated with the occurrence of motor-vehicle crash. METHOD: One hundred and twenty-nine older drivers residing in a metropolitan city volunteered to participate in this retrospective cohort study. Using the driving simulator, appropriate driving tasks were devised to test the older drivers, whose performances were assessed by 10 reliable assessment criteria. Logistic regression analysis was then undertaken to determine those criteria that influence the self-reported crash outcome. RESULTS: As expected, driving skill of older drivers was found to decline with age. Over 60% of the sample participants reported having at least one motor-vehicle crash during the past year. Adjusting for age in a logistic regression analysis, the cognitive abilities associated with the crash occurrence were working memory, decision making under pressure of time, and confidence in driving at high speed. SUMMARY: The findings of this retrospective study indicated those individuals at inflated risk of vehicle crashes could be identified using the PC-based interactive driving simulator. Prospective studies need to be undertaken to determine whether the driving simulator can predict future crash events. IMPACT ON INDUSTRY: This study demonstrated an economical driving simulator approach to screen out problematic or unsafe older drivers before a more detailed but expensive road test is considered.

Accidents, Traffic↗

PubMed2003

A bivariate zero-inflated Poisson regression model to analyze occupational injuries.

The aim of many occupational safety interventions is to reduce the incidence of injury. However, when measuring intervention effectiveness within a period, population-based accident count data typically contain a large proportion of zero observations (no injury). This situation is compounded where injuries are categorized in a binary manner according to an outcome of interest. The distribution thus comprises a point mass at zero mixed with a non-degenerate parametric component, such as the bivariate Poisson. In this paper, a bivariate zero-inflated Poisson (BZIP) regression model is proposed to evaluate a participatory ergonomics team intervention conducted within the cleaning services department of a public teaching hospital. The findings highlight that the BZIP distribution provided a satisfactory fit to the data, and that the intervention was associated with a significant reduction in overall injury incidence and the mean number of musculoskeletal (MLTI) injuries, while the decline in injuries of a non-musculoskeletal (NMLTI) nature was marginal. In general, the method can be applied to assess the effectiveness of intervention trials on other populations at high risk of occupational injury.

Accidents, Occupational↗

PubMed2003

Assessing the driving performance of older adult drivers: on-road versus simulated driving.

To validate a laboratory-based driving simulator in measuring on-road driving performance, 129 older adult drivers were assessed with both the simulator and an on-road test. The driving performance of the participants was gauged by appropriate and reliable age-specific assessment criteria, which were found to be negatively correlated with age. Using principal component analysis, two performance indices were developed from the criteria to represent the overall performance in simulated driving and the on-road assessment. There was significant positive association between the two indices, with the simulated driving performance index explaining over two-thirds of the variability of the on-road driving performance index, after adjustment for age and gender of the drivers. The results supported the validity of the driving simulator and it is a safer and more economical method than the on-road testing to assess the driving performance of older adult drivers.

Accidents, Traffic↗