Biomedical subjects

M S Hobbs

Publications and source records attributed to M S Hobbs.

At least 19 recordsLinked to original sources

PubMed2006

Surgeon experience and trends in intraoperative complications in laparoscopic cholecystectomy.

BACKGROUND: Intraoperative complications, particularly bile duct injuries (BDIs), have increased since the introduction of laparoscopic cholecystectomy (LC). This excess risk is expected to decline as surgeon experience in laparoscopic surgery increases. METHODS: This was a population-based study of trends in intraoperative injuries in 33 309 cholecystectomies carried out in Western Australia between 1988 and 1998, based on hospital discharge abstracts. Endpoints were identified from diagnostic and procedure codes in index or postoperative readmissions, or a register of endoscopic retrograde cholangiopancreatography procedures, and validated using hospital records. Multivariate analysis was used to estimate the risk of complications associated with potential risk factors. RESULTS: Following the introduction of LC in 1991, the prevalence of all complications doubled by 1994 then stabilized, whereas that of BDI declined after 1994. The risk of complications increased with age, was higher in men, teaching and country hospitals, and was higher for LC and more complicated operations. It was lower when intraoperative cholangiography was performed and with increasing surgeon experience. Approximately 20 per cent of all complications and 30 per cent of BDIs were attributable to surgeons who had performed 200 or fewer cholecystectomies in the previous 5 years. CONCLUSION: The risk of intraoperative complications declined with increasing surgical experience and use of intraoperative cholangiography.

Bile Ducts↗

PubMed2001

Prior calcium channel blockade and short-term survival following acute myocardial infarction.

There is concern over the safety of calcium channel blockers (CCBs) in acute coronary disease. We sought to determine if patients taking calcium channel blockers (CCBs) at the time of admission with acute myocardial infarction (AMI) had a higher case-fatality compared with those taking beta-blockers or neither medication. Clinical and drug treatment variables at the time of hospital admission predictive of survival at 28 days were examined in a community-based registry of patients aged under 65 years admitted to hospital for suspected AMI in Perth, Australia, between 1984 and 1993. Among 7766 patients, 1291 (16.6%) were taking a CCB and 1259 (16.2%) a betablocker alone at hospital admission. Patients taking CCBs had a worse clinical profile than those taking a beta-blocker alone or neither drug (control group), and a higher unadjusted 28-day mortality (17.6% versus 9.3% and 11.1% respectively, both P < 0.001). There was no significant heterogeneity with respect to mortality between nifedipine, diltiazem, or verapamil when used alone, or with a beta-blocker. After adjustment for factors predictive of death at 28 days, patients taking a CCB were found not to have an excess chance of death compared with the control group (odds ratio [OR] 1.06, 95% confidence interval [CI]; 0.87, 1.30), whereas those taking a beta-blocker alone had a lower odds of death (OR 0.75, 95% CI; 0.59, 0.94). These results indicate that established calcium channel blockade is not associated with an excess risk of death following AMI once other differences between patients are taken into account, but neither does it have the survival advantage seen with prior beta-blocker therapy.

Adrenergic beta-Antagonists↗

PubMed2001

Opportunities for control of coronary heart disease in Australia.

OBJECTIVE: To estimate the number of coronary events that could be prevented in Australia each year by the use of preventive and therapeutic strategies targeted to subgroups of the population based on their levels of risk and need. METHODS: Estimates of risk reduction from the published literature, prevalence estimates of elevated risk factor levels from the 1995 National Health Survey and treatment levels from the Australian collaborating centres in the World Health Organization's MONICA Project were used to calculate numbers of coronary events preventable among men and women aged 35-79 years in Australia. RESULTS: Approximately 14,000 coronary events could be avoided each year if the mean level of cholesterol in the population was reduced by 0.5 mmol/L, smoking prevalence was halved and prevalence of physical inactivity was reduced to 25%. This represents a reduction in coronary events of about 40%. Even with less optimistic targets, a reduction of 20% could be attained, while the achievement of some internationally recommended targets could lead to almost 50% reduction. In the short term, aggressive medical treatment of people with elevated levels of risk factors and established coronary disease offers the greatest opportunity for reducing coronary events. CONCLUSION: A comprehensive approach to reduce levels of behavioural and biological risk factors and improve the use of effective treatment could lead to a large reduction in coronary event rates. In the long term, primary prevention--especially to reduce smoking, lower cholesterol levels and increase exercise--has the potential to reduce the population levels of risk and hence contain the national cost of coronary disease.

Adult↗

PubMed2000

Cocaine inhibits human neutrophil phagocytosis and phagolysosomal acidification in vitro.

Cocaine, used intravenously, increases the risk of infections, but its effects on neutrophil phagocytosis have not been examined in vitro. Human neutrophils were suspended in cocaine hydrochloride 0, 1, 10, 50, 100 or 200 microg/ml in Hank's balanced salt solution to which was added a phagocytic meal of killed Saccharomyces cerevisiae stained with the pH indicator dye bromcresol purple. Yeast per phagocytosing neutrophil and the percent neutrophils phagocytosing yeast were reduced in neutrophils treated with cocaine 100 and 200 microg/ml (P < 0.05). When examined for percent of yeast phagocytosed after 10 minutes, neutrophils treated with cocaine 1-200 microg/ml demonstrated a decrease (P < 0.05). However, at 60 minutes only neutrophils treated with cocaine 50 and 100 microg/ml still showed a decrease in percent of yeast phagocytosed. Phagolysosomal acidification was impaired in neutrophils treated with 50, 100 and 200 microg/ml cocaine. Thus, cocaine inhibits neutrophil phagocytosis and phagolysosomal acidification in vitro, offering a reason for cocaine users/abusers to have impaired host defense and to be potentially at higher risk for infections.

Cocaine↗

PubMed1999

Finding bile duct injuries using record linkage: a validated study of complications following cholecystectomy.

Laparoscopic cholecystectomy was introduced to Western Australia in 1991 and has become the method of choice for this procedure, although there are concerns about complications, particularly bile duct injuries. Previous studies have investigated this problem but have not confirmed the accuracy of coded information. We used Record Linkage to link operative admissions to subsequent admissions for all people who underwent cholecystectomy between 1988 and 1994. Using ICD9-CM discharge codes, we identified patients with an associated complication. We validated these patients' medical notes to obtain the proportion of complications in the period encompassing the introduction of laparoscopic cholecystectomy. We found 48 bile duct injuries in 413 patients. Of these 43% were found using complication codes on the operative admission, 79% using linked records of subsequent admissions, and 90% by adding lists of complicated cases from the three teaching hospitals. Any epidemiological research that uses surgical complication codes from operative admissions, particularly in the absence of a specific ICD9-CM code, will lead to significantly underestimating the prevalence of complications. By using record linkage, and validating medical records, we captured a significant proportion of complications.

Bile Ducts↗

PubMed1999

Complications of cholecystectomy: risks of the laparoscopic approach and protective effects of operative cholangiography: a population-based study.

BACKGROUND: Previous studies suggest that laparoscopic cholecystectomy (LC) is associated with an increased risk of intraoperative injury involving the bile ducts, bowel, and vascular structures compared with open cholecystectomy (OC). Population-based studies are required to estimate the magnitude of the increased risk, to determine whether this is changing over time, and to identify ways by which this might be reduced. METHODS: Suspected cases of intraoperative injury associated with cholecystectomy in Western Australia in the period 1988 to 1994 were identified from routinely collected hospital statistical records and lists of persons undergoing postoperative endoscopic retrograde cholangiopancreatography. The case records of suspect cases were reviewed to confirm the nature and site of injury. Ordinal logistic regression was used to estimate the risk of injury associated with LC compared with OC after adjusting for confounding factors. RESULTS: After the introduction of LC in 1991, the proportion of all cholecystectomy cases with intraoperative injury increased from 0.67% in 1988-90 to 1.33% in 1993-94. Similar relative increases were observed in bile duct injuries, major bile leaks, and other injuries to bowel or vascular structures. Increases in intraoperative injury were observed in both LC and OC. After adjustment for age, gender, hospital type, severity of disease, intraoperative cholangiography, and calendar period, the odds ratio for intraoperative injury in LC compared with OC was 1.79. Operative cholangiography significantly reduced the risk of injury. CONCLUSION: Operative cholangiography has a protective effect for complications of cholecystectomy. Compared with OC, LC carries a nearly twofold higher risk of major bile, vascular, and bowel complications. Further study is required to determine the extent to which potentially preventable factors contribute to this risk.

Aged↗

PubMed1999

Population-based linkage of health records in Western Australia: development of a health services research linked database.

OBJECTIVES: To introduce the Western Australian Health Services Research Linked Database as infrastructure to support aetiologic, utilisation and outcomes research. To compare the study population, data resources, technical systems and organisational supports with international best practice in record linkage and health research. METHOD AND RESULTS: The WA Linked Database systematically links the available administrative health data within an Australian State of 1.7 million people. It brings together, initially, six core data elements (birth records, midwives' notifications, cancer registrations, in-patient hospital morbidity, in-patient and public out-patient mental health services data and death records). It will be updated regularly and is designed, in future extensions, to include data on primary, residential and domiciliary care and health surveys. Linkage uses probabilistic matching of patient names and other identifiers. Geocodes for spatial analysis are assigned using address linkage and mapping software. By June 1997, the project had taken 2 1/2 years to develop the system and link seven million core data records from 1980 to 1995. CONCLUSIONS: The system is consistent with international benchmarks, from four centres of excellence, for the study population, core datasets, matching and geocoding, and collaborative networks. There are prospects to redress deficiencies in primary medical contact and other data resources, validation studies, tracing systems and a more supportive legal framework. IMPLICATIONS: The WA Linked Database will be used in combination with medical record audits to provide a comprehensive evaluation of health system performance.

Data Collection↗

PubMed1998

Vitamin A and cancer prevention I: observations in workers previously exposed to asbestos at Wittenoom, Western Australia.

Our aim was to describe a vitamin A-based cancer prevention program for former asbestos workers and to check for possible harmful effects by comparing rates of disease and death in study subjects with subjects who chose not to join. All subjects had been occupationally exposed to crocidolite at Wittenoom Gorge between 1943 and 1966; 1,677 subjects indicated interest in the program and 1,203 joined between June 1990 and May 1995. Comparison subjects consisted of 996 former workers known to be alive in Western Australia in 1990 who did not join the program. Program subjects were provided with annual supplies of vitamin A (either synthetic beta-carotene or retinol), help in quitting smoking and dietary advice. The comparison group received only mail contact. Both groups were followed up to December 1994 for vital status and cancer information, and rates of cancer and death from various causes were compared. Mortality in both groups was higher than expected (standardised mortality ratio 1.23 in program subjects and 1.67 in comparison subjects). After adjustment for age, smoking and asbestos exposure, the relative rates in participants compared with non-participants was below I for all examined cancers and causes of death. For mesothelioma and lung cancer, group differences increased with time from entry, whereas other differences dissipated with time. No significant side effects were reported. In conclusion, program participants had significantly lower mortality than non-participants, but the rates of the 2 groups converged with time.

Adult↗

PubMed1998

Vitamin A and cancer prevention II: comparison of the effects of retinol and beta-carotene.

Former blue asbestos workers known to be at high risk of asbestos-related diseases, particularly malignant mesothelioma and lung cancer, were enrolled in a chemo-prevention program using vitamin A. Our aims were to compare rates of disease and death in subjects randomly assigned to beta-carotene or retinol. Subjects were assigned randomly to take 30 mg/day beta-carotene (512 subjects) or 25,000 IU/day retinol (512 subjects) and followed up through death and cancer registries from the start of the study in June 1990 till May 1995. Comparison between groups was by Cox regression in both intention-to-treat analyses and efficacy analyses based on treatment actually taken. Median follow-up time was 232 weeks. Four cases of lung cancer and 3 cases of mesothelioma were observed in subjects randomised to retinol and 6 cases of lung cancer and 12 cases of mesothelioma in subjects randomised to beta-carotene. The relative rate of mesothelioma (the most common single cause of death in our study) for those on retinol compared with those on beta-carotene was 0.24 (95% CI 0.07-0.86). In the retinol group, there was also a significantly lower rate for death from all causes but a higher rate of ischaemic heart disease mortality. Similar results were found with efficacy analyses. Our results confirm other findings of a lack of any benefit from administration of large doses of synthetic beta-carotene. The finding of significantly lower rates of mesothelioma among subjects assigned to retinol requires further investigation.

Adult↗

PubMed1998

Environmental exposure to crocidolite and mesothelioma: exposure-response relationships.

This study aimed to estimate exposure-response relationships for mesothelioma and environmental exposure to crocidolite. All 4,659 former residents of Wittenoom, Western Australia (WA) who lived there between 1943 and 1993 for at least 1 mo and were not directly employed in the crocidolite industry, were followed-up through the WA death, cancer and mesothelioma registries, electoral rolls, and telephone books. In 1992, all subjects who should be traced were sent a questionnaire. Exposure levels were estimated from results of periodic environmental surveys and duration of residence. Incidence rates were standardized to the World Population and Cox Regression was used to estimate the effects of exposure on incidence. To the end of 1993, 27 cases of mesothelioma were diagnosed. Mesothelioma cases stayed longer at Wittenoom, had a higher average intensity of exposure, and a higher cumulative exposure to crocidolite than control subjects. The standardized incidence of mesothelioma was 260 per million person-years, and was similar for males and females. The rate increased significantly with time from first exposure, duration of exposure and cumulative exposure. At these levels of crocidolite exposure, there is a significantly increased risk of mesothelioma, which is dose-dependent.

Adult↗

PubMed1998

Arrhythmias and mortality after myocardial infarction in diabetic patients. Relationship to diabetes treatment.

OBJECTIVE: To assess the relationship between clinical course after acute myocardial infarction (AMI) and diabetes treatment. RESEARCH DESIGN AND METHODS: Retrospective analysis of data from all patients aged 25-64 years admitted to hospitals in Perth, Australia, between 1985 and 1993 with AMI diagnosed according to the International Classification of Diseases (9th revision) criteria was conducted. Short- (28-day) and long-term survival and complications in diabetic and nondiabetic patients were compared. For diabetic patients, 28-day survival, dysrhythmias, heart block, and pulmonary edema were treated as outcomes, and factors related to each were assessed using multiple logistic regression. Diabetes treatment was added to the model to assess its significance. Long-term survival was compared by means of a Cox proportional hazards model. RESULTS: Of 5,715 patients, 745 (12.9%) were diabetic. Mortality at 28 days was 12.0 and 28.1% for nondiabetic and diabetic patients, respectively (P < 0.001); there were no significant drug effects in the diabetic group. Ventricular fibrillation in diabetic patients taking glibenclamide (11.8%) was similar to that of nondiabetic patients (11.0%) but was lower than that for those patients taking either gliclazide (18.0%; 0.1 > P > 0.05) or insulin (22.8%; P < 0.05). There were no other treatment-related differences in acute complications. Long-term survival in diabetic patients was reduced in those taking digitalis and/or diuretics but type of diabetes treatment at discharge had no significant association with outcome. CONCLUSIONS: These results do not suggest that ischemic heart disease should influence the choice of diabetes treatment regimen in general or of sulfonylurea drug in particular.

Adult↗

PubMed1997

Declining rates of coronary heart disease in New Zealand and Australia, 1983-1993.

The authors report the results of 10 years of monitoring of trends in the rates of major nonfatal and fatal coronary events and in case fatality in Auckland, New Zealand, and in Newcastle and Perth, Australia. Continuous surveillance of all suspected myocardial infarctions and coronary deaths in people aged 35-64 years was undertaken in the three centers as part of the World Health Organization's Multinational Monitoring of Trends and Determinants in Cardiovascular Disease (MONICA) Project. For nonfatal definite myocardial infarction, there were statistically significant declines in rates in all centers in both men and women, with estimated average changes between 2.5% and 3.7% per year during the period 1984-1993. Rates of all coronary deaths also declined significantly in all three populations for both men and women. In absolute terms, there was, in general, a greater reduction in prehospital deaths than in deaths after hospitalization. Although 28-day case fatality remains high at between 35% and 50%, in the Australian centers it declined significantly by between 1.0% and 2.9% per year, and in Auckland there was also a small decline. However, since most deaths occur outside the hospital in people without a previous history of coronary heart disease, an increased emphasis on primary prevention is necessary.

Adult↗

PubMed1996

Exposure to crocidolite and the incidence of different histological types of lung cancer.

OBJECTIVES: To estimate the relations between exposure to both tobacco smoke and crocidolite and the incidence of various histological types of lung cancer. METHODS: In 1979 all former workers from the Wittenoom asbestos industry who could be traced were sent a questionnaire on smoking history. Of 2928 questionnaires sent, satisfactory replies were received from 2400 men and 149 women. Of the men, 80% had smoked at some time and 50% still smoked. Occupational exposure to crocidolite was known from employment records and follow up was maintained through death and cancer registries in Australia with histological diagnoses obtained from the relevant State Cancer Registry. Conditional logistic regression was used to estimate the effects of tobacco and asbestos exposure on incidence of different cell types of lung cancer in a nested case-control design. RESULTS: Between 1979 and 1990, 71 cases of lung cancer occurred among men in this cohort: 27% squamous cell carcinoma, 31% adenocarcinoma, 18% small cell carcinoma, 11% large cell carcinoma, and 13% unclassified or indeterminate. Two of the classified cases and one unclassified case had never smoked. The incidence of both squamous and adenocarcinoma types of lung cancer were greatest in ex-smokers and in those subjects with the highest levels of exposure to crocidolite. After adjustment for smoking habit, the increase in incidence of lung cancer with increasing exposure to crocidolite was greater for squamous cell carcinoma than for adenocarcinoma. CONCLUSIONS: The results from this study have shown significant exposure-response effects for exposure to crocidolite, and both adenocarcinoma and squamous cell carcinoma of the lung. They also provide some further evidence against the theory that parenchymal fibrosis induced by asbestos is a necessary precursor to asbestos induced lung cancer.

Adenocarcinoma↗

PubMed1994

Early identification of patients at low risk of death after myocardial infarction and potentially suitable for early hospital discharge.

OBJECTIVES: To find (a) whether data available shortly after admission for acute myocardial infarction can provide a reliable prognostic indicator of survival at 28 days, and (b) whether such an indicator might be used to identify patients at low risk of death and suitable for early discharge. DESIGN: Retrospective analysis of data collected on patients admitted to a coronary care unit for acute myocardial infarction. A validation sample was selected at random from these patients. SETTING: Coronary care units in Perth, Western Australia. SUBJECTS: 6746 patients aged under 65 and resident in the Perth Statistical Division who during 1984-92 were admitted to a coronary care unit with symptoms of myocardial infarction. MAIN OUTCOME MEASURES: Sensitivity and specificity of several models for predicting survival at 28 days after myocardial infarction, and detailed performance characteristics of a particular model. RESULTS: Patients with a pulse rate of 100 beats/min or less, aged 60 or under, and with symptoms typical of myocardial infarction, no past history of myocardial infarction or diabetes, and no significant Q wave in the admission electrocardiogram had a very high chance of survival at 28 days (99.2%). These patients made up one third of all patients studied. CONCLUSION: The prognostic index identifies patients very soon after admission who are at low risk of death and potentially eligible for early discharge from hospital or the coronary care unit. Computing the index does not need complex cardiac investigations.

Adult↗

PubMed1994

Mortality trends, 1965 to 1989, in Busselton, the site of repeated health surveys and interventions.

The community of Busselton in Western Australia has participated in repeated cross-sectional health surveys and other health interventions since 1966. Health surveys of adults were conducted every three years from 1966 to 1981. Health interventions, including programs for high blood pressure, smoking, high blood cholesterol levels and obesity, were implemented in the community. Mortality rates for the Busselton area are compared with rates for the remainder of the southwest region of Western Australia in an attempt to determine if the surveys and associated interventions have had any impact on survival. Statistical comparisons via Poisson regression analysis showed that mortality rates for males over the period 1965 to 1989 in Busselton declined at a similar rate to the southwest. However, for females, especially those aged 45 to 74 years, mortality rates declined significantly faster in Busselton than in the southwest, suggesting a beneficial impact on survival of the surveys and associated interventions.

Adult↗

PubMed1993

A study of the characteristics and needs of people transferred from acute hospitals to nursing homes.

OBJECTIVES: To describe the categories of people being approved for admission to nursing homes; to consider whether any alternatives would have been more appropriate; and to outline the care needed for each category. PARTICIPANTS AND SETTING: Patients in acute-care facilities in metropolitan Perth for whom a request had been made for nursing home admission. DESIGN: Patients were interviewed (by R B L and M D) and records in the acute hospital were examined. A second interview of those patients still available was conducted after their transfer to the nursing home. RESULTS: Nursing care was considered necessary for 123 of the 201 people seen in the acute hospitals; domestic care in a standard hostel for 24 people; care in a special dementia unit (SDU) hostel for 26 people; and care in a psychiatric institution for 16 people. Twelve others had various specific needs. Several different categories were identified in the group needing nursing care. CONCLUSIONS: Applicants for nursing home admission do not form a homogeneous group; there are several categories with different needs. SDU hostels should be added to the available facilities. In addition to undertaking the assessment of nursing home applicants, personnel from geriatric services should be encouraged to become involved in their continuing care.

Aged↗

PubMed1993

Malignant mesothelioma after environmental exposure to blue asbestos.

To determine the magnitude of the population at risk from non-occupational exposure to crocidolite at Wittenoom, Western Australia (WA), a cohort of 4,890 residents who never worked for the mining company Australian Blue Asbestos (ABA) has been assembled from all 18,553 available records: the local school register, hospital attendances, the WA electoral roll, birth certificates, workers who answered a mailed questionnaire in 1979, participants in a cancer-prevention programme using vitamin-A dietary supplements, and other sources. The majority of subjects were relatives and friends of ABA employees, and nearly half the cohort were either born at Wittenoom or first went there as children under 10 years of age. As most residents were at Wittenoom when the mine and mill were in operation during the period 1943 to 1966, 82% were first exposed to crocidolite 20 or more years ago. The proportion of other workers (i.e., not employed by ABA) and their families increased once the mining operations ceased. To date, 24 cases of mesothelioma have been reported in this cohort: 9 males and 15 females. Time from first exposure to diagnosis ranged from 23 to 44 years and residence in Wittenoom ranged from 6 weeks to 11 years.

Adolescent↗

PubMed1993

Retention and survival of hostel residents--a 12 year study.

BACKGROUND: The admission of a proportion of disabled people to hostels is inevitably followed by their transfer to nursing homes. Our hypothesis was that such admissions are justified in terms of quality of life and the cost to the community, notwithstanding the necessity of subsequent transfer. AIMS: To test this hypothesis by measuring the retention and survival times of residents in hostel and in nursing home; to consider the relevance of these factors to the future policy of the two institutions. METHODS: A retrospective study was made of 159 residents admitted over a period of 12 years to a hostel with 32 places. Times spent in the hostel and in the nursing home were recorded. Probabilities of survival in hostel and in nursing home were calculated according to the Kaplan-Meier method. Comparison with the expected survival of a matched cohort of the total population was determined. Estimation was made, using the SAS software package, of the likely number of places needed in nursing homes for residents following transfer. RESULTS: Although the majority of hostel residents eventually needed nursing home care, a worthwhile proportion of their total institutional time (approximately two-thirds) was spent in the hostel. Ongoing support from the personnel in a geriatric service is likely to increase retention time in the hostel. Because of the ultimate outcome for the majority of residents, planning for hostel care should include consideration of places needed in nursing homes.

Aged↗