Using quality indicators to compare outcomes of permanent cardiac pacemaker implantation among publicly and privately funded patients.

BACKGROUND: Funding source/insurance status has been associated with disparity in the management and outcomes of cardiovascular disease, with poorer outcomes among disadvantaged groups. AIM: Using proposed quality indicators for permanent pacemaker (PPM) implantation and administrative data, this study aimed to determine whether quality indicator-based outcomes of PPM implantation were comparable for publicly and privately funded patients within Australia's two-tier health system. METHODS: A population-based cohort study of adults implanted with a PPM between 1995 and 2009 in Western Australia. The association of funding outcomes derived from linked administrative data was tested in multivariate logistic regression models. RESULTS: There were 9748 PPMs implanted, 48% being among privately funded patients. The mean age was 75 years for both public and private patients. Private patients had better health status (fewer with cardiac conditions and lower non-cardiac comorbidity scores), were less likely to be an emergency admission (33% vs 60%, P < 0.001) and more likely to have dual- or triple-chamber pacing. Mean length of stay was significantly greater for private patients (4.3 (standard deviation 6.3) vs 5.1 (6.8) days <0.001), related to longer elective admissions. Crude mortality was lower for private patients in-hospital (0.7 vs 1.3%), 30-day post-procedure (1.3 vs 2.1%) and at 1 year (7.3 vs 9.5%). Emergency admission, comorbidity and other demographic and clinical factors, not funding source, were significant predictors of these outcomes. CONCLUSIONS: There was no difference between publicly and privately funded patients in study outcomes, after adjustment for demographic and clinical factors. The exception was longer hospital stay for elective PPM among privately funded patients.

Evaluation of long-term clinical and health service outcomes following coronary artery revascularisation in Western Australia (WACARP): a population-based cohort study protocol.

INTRODUCTION: Coronary artery bypass grafting (CABG) and percutaneous coronary interventions (PCI) are procedures commonly performed on patients with significant obstructive coronary artery disease to relieve symptoms of ischaemia, improve survival or both. Although the efficacy of both procedures at the individual level has been established, the impact of advances in coronary artery revascularisation procedures (CARP) on long-term outcomes and cost-effectiveness at the population level are yet to be assessed. Our aim is to evaluate a minimum of 6-year outcomes and costs for the total population of patients who had CARP in Western Australia (WA) in 2000-2005. METHODS AND ANALYSIS: This retrospective population cohort study will link clinical and administrative health data for a previously defined cohort including all patients in WA who had a CARP in the period 2000-2005. The cohort consists of 19,014 patients who had 21,175 procedures (15,429 PCI and 5746 CABG). We are now collecting a minimum of 6 years follow-up of morbidity and mortality data for the cohort using the WA Data Linkage System, clinical registries and hospital records, with 12 years follow-up for cases in the year 2000. Comparison of long-term outcomes for different CARP will be reported (PCI vs CABG; bare metal stents vs drug-eluting stents vs CABG). Cost-effectiveness analysis of CARP from the perspective of the healthcare sector will be performed using individual level cost data and average costs from Australian Refined Diagnosis Related Groups. ETHICS AND DISSEMINATION: This study has received ethics approval from the University of Western Australia, the Western Australian Department of Health and all participating hospitals. Being a large population cohort study, approval included a waiver of informed consent. All findings will be presented at local, national and international healthcare/academic conferences and published in peer-reviewed journals.

Evidence-based prescribing of drugs for secondary prevention of acute coronary syndrome in Aboriginal and non-Aboriginal patients admitted to Western Australian hospitals.

AIMS: To assess the level of evidence-based drug prescribing for acute coronary syndrome (ACS) at discharge from Western Australian (WA) hospitals and determine predictors of such prescribing in Aboriginal and non-Aboriginal patients. METHODS: All Aboriginal (2002-2004) and a random sample of non-Aboriginal (2003) hospital admissions with a principal diagnosis of ACS were extracted from the WA Hospital Morbidity Data Collection of WA Data Linkage System. Clinical information, history of co-morbidities and drugs were collected from medical notes by trained data collectors. Evidence-based prescribing (EBP) was defined as prescribing of aspirin, statin and beta-blocker or angiotensin-converting enzyme inhibitor/angiotensin II antagonist. RESULTS: Records for 1717 ACS patients discharged alive from hospitals were reviewed. The majority of patients (71%) had EBP, and there was no significant difference between Aboriginal and non-Aboriginal patients (70% vs 71%, P = 0.36). Conversely, a significantly higher proportion of Aboriginal patients had none of the drugs prescribed compared with non-Aboriginal patients (11% vs 7%, P < 0.01). EBP for ACS was independently associated with male sex (odds ratio (OR) 1.63, 95% confidence interval (CI) 1.26-2.11), previous admission for ACS (OR 1.83, 95% CI 1.39-2.42) and diabetes (OR 1.36, 95% CI 1.04-1.79). However, ACS patients living in regional and remote areas, attending district or private hospitals, or with a history of chronic obstructive pulmonary disease were significantly less likely to have ACS drugs prescribed at discharge. CONCLUSIONS: Opportunity exists to improve prescribing of recommended drugs for ACS patients at discharge from WA hospitals in both Aboriginal and non-Aboriginal patients. Attention regarding pharmaceutical management post-ACS is particularly required for patients from rural and remote areas, and those attending district and private hospitals.

Impact of new biomarkers of myocardial damage on trends in myocardial infarction hospital admission rates from population-based administrative data.

Use of troponin testing in the diagnosis of myocardial infarction substantially increases the number of cases diagnosed as myocardial infarction among suspected cases in comparison with previous criteria. However, the impact of troponin testing on rates reported in national statistics that use routinely collected hospital morbidity data is uncertain. The authors developed Poisson regression models to estimate the effect of troponin testing on long-term trends in hospital admission rates in Perth, Western Australia, from 1980 to 2004. Troponin tests were used for 10.5% of patients with suspected myocardial infarction in 1996, rising rapidly to more than 90% of patients from 2001 onward. Fitted models that assumed a continuing linear decline estimated that 100% use of troponin testing in cases of suspected myocardial infarction would lead to an apparent increase in hospital admission rates of 42% (95% confidence interval (CI): 28, 56) in men and 21% (95% CI: 4, 41) in women as compared with rates that would be expected if previous linear trends had continued. Smaller effects of 30% (95% CI: 14, 48) in men and -2% (95% CI: -21, 20) in women were found in fitted models that assumed an underlying attenuating trend in the rates. Similarly constructed logistic regression trend models found no significant effect of troponin testing on trends in 28-day case-fatality.

Mortality of former crocidolite (blue asbestos) miners and millers at Wittenoom.

BACKGROUND: Blue asbestos was mined and milled at Wittenoom in Western Australia between 1943 and 1966. METHODS: Nearly 7000 male workers who worked at the Wittenoom mine and mill have been followed up using death and cancer registries throughout Australia and Italy to the end of 2000. Person-years at risk were derived using two censoring dates in order to produce minimum and maximum estimates of asbestos effect. Standardised mortality ratios (SMRs) compare the mortality of the former Wittenoom workers with the Western Australian male population. RESULTS: There have been 190 cases of pleural and 32 cases of peritoneal mesothelioma in this cohort of former workers at Wittenoom. Mortality from lung cancer (SMR = 1.52), pneumoconiosis (SMR = 15.5), respiratory diseases (SMR = 1.58), tuberculosis (SMR = 3.06), digestive diseases (SMR = 1.47), alcoholism (SMR = 2.24) and symptoms, signs and ill defined conditions (SMR = 2.00) were greater in this cohort compared to the Western Australian male population. CONCLUSION: Asbestos related diseases, particularly malignant mesothelioma, lung cancer and pneumoconiosis, continue to be the main causes of excess mortality in the former blue asbestos miners and millers of Wittenoom.

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.

Trends in coronary artery revascularisation procedures in Western Australia, 1980-2001.

OBJECTIVES: To describe trends in the use of coronary artery revascularisation procedures (CARPs) and to determine whether or when CARP rates will stabilise. SETTING: State of Western Australia. PATIENTS: All patients treated by coronary artery bypass grafting (CABG) or percutaneous coronary intervention (PCI) between 1980 and 2001. DESIGN: Descriptive study. MAIN OUTCOME MEASURES: Age standardised rates of first and total CARPs, CABGs, and PCIs. RESULTS: Overall rates for both total and first CARPs among men and women rose steeply from 1980 to 1993, when they abruptly stabilised or actually started to decline. Rates in age groups under 65 years tended to rise earlier in the period and remained relatively flat, while rates for people over the age of 75 years started to rise later and were still increasing at the end of the study. CONCLUSIONS: Despite continuing increases in capacity to perform both CABG and PCI in Western Australia and evidence of continuing increases in the use of CARPs in the elderly population, rates appear to have stabilised for the first time since they were introduced.

Trends in two year risk of repeat revascularisation or death from cardiovascular disease after coronary artery bypass grafting or percutaneous coronary intervention in Western Australia, 1980-2001.

AIMS: To investigate whether, over the 21 year period 1980-2001, there had been a reduction in the risk of repeat revascularisation or death from cardiovascular disease in the cohort of all patients who were treated by coronary revascularisation in Western Australia. SETTING: State of Western Australia. PATIENTS: All patients treated by coronary artery bypass grafting (CABG) or percutaneous coronary intervention (PCI) between 1980 and 2001. DESIGN: Cohort study. MAIN OUTCOME MEASURES: Risk of repeat coronary artery revascularisation procedures (CARP) and risk of death from cardiovascular disease after first CARP. RESULTS: After a CABG procedure, the two year risk of repeat revascularisation remained low (less than 2%) across the period 1980-2001. For PCI, however, this risk declined significantly from 33.6% in 1985-9 to 12.4% in 2000-1. The risk of death from cardiovascular disease after a CARP declined by about 50% between 1985 and 2001. CONCLUSIONS: Outcomes such as the risk of repeat revascularisation and the risk of death from cardiovascular disease have improved significantly for patients who underwent CARPs across the period 1980-2001. This has occurred despite an increasing trend in first CARP rates among older people and those with a recent history of myocardial infarction.

Risk of death in prisoners after release from jail.

OBJECTIVE: To compare the risk of death in a cohort of Western Australian released prisoners with the risk experienced by the general population of Western Australia. METHODS: A cohort study of prisoners in Western Australia whose last date of release ranged from 1 January 1994 to 1 January 1999. Overall mortality and cause of death were determined by data linkage to the Registrar General's record of deaths. RESULTS: Aboriginal prisoners had a significantly lower survival rate after release than non-Aboriginal prisoners (p < 0.0001). When compared with their peers in the Western Australian community, both Aboriginal and non-Aboriginal prisoners were found to have an increased relative risk of death. Female non-Aboriginal released prisoners aged between 20 and 40 years were 17.8 (95% CI 8.1-27.5) times more likely to die than other female non-Aboriginals in Western Australia in the same age range. Male non-Aboriginal prisoners aged 20-40 years were 6.3 (95% CI 5.2-7.4) times more likely to die than their counterparts in the WA community. Female Aboriginal released prisoners were 3.4 (95% CI 1.2-5.6) times more likely to die than their peers, while male Aboriginal released prisoners were 2.9 (95% CI 2.2-3.5) times more likely to die. In their first six months after release, female non-Aboriginal prisoners aged 20 to 40 years were 69.1 (95% CI 17.9-120.3) times more likely to die than their counterparts in the WA community. The main causes of excess death were related to drug and alcohol abuse. CONCLUSION: All prisoners were at greater than expected relative risk of death after release from prison, with female non-Aboriginal prisoners at particularly high relative risk.

Population-based study of carotid endarterectomy in Western Australia.

BACKGROUND: Previous studies reported an increase in the rates of operation following the publication of major trials that demonstrated the benefit of carotid endarterectomy in reducing stroke. The aim of this study was to determine whether carotid endarterectomy rates have continued to rise despite the reducing trend in most manifestations of atherosclerotic cardiovascular disease. METHODS: Record linkage was used to select patients who had a carotid endarterectomy during the interval from 1988 to 2001. Incidence rates were age-standardized and trends were examined with Poisson regression. RESULTS: The rate increased by 13.8 per cent per year between 1988 and 1998; however, from 1999 onwards the rate of carotid surgery fell by 15.8 per cent per year. In octogenarians, the rate increased steadily from 0.9 to 5.1 per 100,000 person-years between 1992 and 2000. The proportion of octogenarians also increased significantly from 0.9 per cent in 1988-1990 to 19.5 per cent in 2000-2001 (chi2=60.11, 4 d.f., P<0.001). CONCLUSION: For the first time a recent decline has been observed in the rate of carotid endarterectomy, most likely owing to a combination of the deceasing incidence of atherosclerosis and more widespread use of effective drugs in the treatment of cardiovascular disease. The rate and proportion of operations in patients aged 80 years or older has increased steadily.

Underuse of beta-blockers following myocardial infarction: a tale of two cities.

AIMS: To measure factors associated with underuse of beta-blocker therapy after myocardial infarction (MI). METHODS: The Newcastle and Perth collaborating centres of the World Health Organization (WHO) MONICA project (to MONItor trends and determinants of Cardiovascular disease) systematically evaluated all patients admitted to hospital in their respective regions with possible MI. A total of 1766 patients in Newcastle and 4,503 patients in Perth, discharged from hospital after confirmed MI from 1985 to 1993, were studied. Rates of beta-blocker use before and after hospital discharge were evaluated and correlates of beta-blocker use determined. RESULTS: Beta-blocker use was similar in Newcastle and Perth before MI (21% of patients in each centre). During hospital admission, beta-blocker therapy was initiated nearly twice as frequently in Perth compared with Newcastle (66 vs 36%, respectively) and more patients were discharged from hospital on beta-blockers in Perth (68%) than in Newcastle (45%). The main factors associated with underuse of beta-blockers in multivariate analysis were geographical centre (odds ratio (OR) for Newcastle compared with Perth 0.3; 95% confidence interval (CI) 0.3-0.3), a history of previous MI (OR 0.6, 95% CI 0.5-0.7), admission to hospital in earlier years (OR 0.4, 95% CI 0.3-0.4 for years 1985-87 compared with years 1991-93), diabetes (OR 0.6, 95% CI 0.5-0.8) and the concomitant use of diuretics (OR 0.5, 95% CI 0.4-0.6) and calcium antagonists (OR 0.6, 95% CI 0.5-0.8). CONCLUSIONS: Underuse of beta-blockers after MI was strongly related to hospital prescribing patterns and not to community use of beta-blockers. Underuse occurred in patients with diabetes and in patients with left ventricular dysfunction, patients who stand to benefit most from beta-blocker use following MI.

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.

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.

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.

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.

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.

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.

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.

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.

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.