Clinical outcomes and health care costs of transferring rural Western Australians for invasive coronary angiography, and a cost-effective alternative care model: a retrospective cross-sectional study.

OBJECTIVES: To examine the severity of coronary artery disease (CAD) in people from rural or remote Western Australia referred for invasive coronary angiography (ICA) in Perth and their subsequent management; to estimate the cost savings were computed tomography coronary angiography (CTCA) offered in rural centres as a first line investigation for people with suspected CAD. DESIGN: Retrospective cohort study. SETTING, PARTICIPANTS: Adults with stable symptoms in rural and remote WA referred to Perth public tertiary hospitals for ICA evaluation during the 2019 calendar year. MAIN OUTCOME MEASURES: Severity and management of CAD (medical management or revascularisation); health care costs by care model (standard care or a proposed alternative model with local CTCA assessment). RESULTS: The mean age of the 1017 people from rural and remote WA who underwent ICA in Perth was 62 years (standard deviation, 13 years); 680 were men (66.9%), 245 were Indigenous people (24.1%). Indications for referral were non-ST elevation myocardial infarction (438, 43.1%), chest pain with normal troponin level (394, 38.7%), and other (185, 18.2%). After ICA assessment, 619 people were medically managed (60.9%) and 398 underwent revascularisation (39.1%). None of the 365 patients (35.9%) without obstructed coronaries (< 50% stenosis) underwent revascularisation; nine patients with moderate CAD (50-69% stenosis; 7%) and 389 with severe CAD (≥ 70% stenosis or occluded vessel; 75.5%) underwent revascularisation. Were CTCA used locally to determine the need for referral, 527 referrals could have been averted (53%), the ICA:revascularisation ratio would have improved from 2.6 to 1.6, and 1757 metropolitan hospital bed-days (43% reduction) and $7.3 million in health care costs (36% reduction) would have been saved. CONCLUSION: Many rural and remote Western Australians transferred for ICA in Perth have non-obstructive CAD and are medically managed. Providing CTCA as a first line investigation in rural centres could avert half of these transfers and be a cost-effective strategy for risk stratification of people with suspected CAD.

Air Ambulance and Emergency Retrieval Services in Western Australia: Caseload Analysis Over 5 Years.

OBJECTIVE: The Royal Flying Doctor Service Western Operations (RFDSWO) provides critical care transfer and retrieval services across 2.5 million km2 to a population of 2.58 million people, providing both primary and secondary retrievals across Western Australia. Flying on average 26 million km/y, retrievals are undertaken with the use of rotary and fixed wing aircraft. Our current fleet includes 16 Pilatus PC-12NGs turboprops, 2 Pilatus PC-24 jets, and access to 1 helicopter (Bell 412). A Hawker XP800 Jet was retired in 2019 after 10 years of service. Our retrieval teams are formed of either a doctor and a nurse or a nurse only on fixed wing missions and a doctor and critical care paramedic for helicopter emergency medical services missions. We present our experiences and caseload statistics over the past 5 years. METHODS: We performed an analysis of our retrieval database looking at the workload from January 1, 2012, to December 31, 2016. This included the number of patients, age, ethnicity, type of retrieval, priority, diagnosis, and distances covered. RESULTS: Forty-three thousand forty-one patients underwent Royal Flying Doctor Service air transfer over a 5-year period. Aboriginal patients comprise around 3.1% of the Western Australian population but accounted for 33% of RFDSWO retrieval missions. There was a mean transfer rate of 8,608 patients per year, which was relatively consistent across the study period. The modal age was 55 to 59 years, but Aboriginal patients were younger with a mean age of 36.5 years (Aboriginal) versus 49.7 years (non-Aboriginal). The types of retrieval undertaken were as follows: primary (17.3%), secondary (81%), and repatriation (1.7%). The urgency/priority of missions was as follows: immediate (7.3%), urgent (54.5%), and semiurgent (38.1%). The 3 most common diagnosis (International Statistical Classification of Diseases, 10th Revision) categories were trauma/injury (22.9%), cardiovascular (22.3%), and gastrointestinal (10.5%). The modal distance flown was 700 km per mission. CONCLUSION: RFDSWO has 1 of the largest retrieval workloads in the world, covering a landmass comparable with Western Europe. This brings with it a variety of challenging cases and complex logistics, often in extremely harsh and remote environments. We bring a wide breadth of experience in the area of retrieval medicine, and our aim is to share these experiences with other teams.

Folate levels and cancer morbidity and mortality: prospective cohort study from Busselton, Western Australia.

PURPOSE: To test a community population for the hypothesis that carcinogenesis is related to blood folate levels. METHODS: Prospective analysis of cancer mortality data for a cohort of 964 men (person-time follow up: 20,254 years) and 1024 women (person-time follow up: 24,970 years) and morbidity data for a subcohort, all of whom participated in the 1969 Busselton (Western Australia) Health survey. Outcome measures were adjusted hazard ratios according to baseline folate levels for total cancer mortality and morbidity and site specific mortality and morbidity for colorectal, lung, breast, and prostate cancers. RESULTS: In total, there were 278 cancer deaths--45 from colorectal cancer, 44 from lung cancer, 15 from breast cancer, and 31 from prostate cancer. Decreased serum folate levels showed an independent association with increased prostate cancer mortality risk, the adjusted hazard ratio per decrease of 2 microg/L was 1.56 (CI: 1.05, 2.38), men whose levels were in the lowest quartile had an adjusted hazard ratio of 4.79 (CI: 1.56, 14.43) for subsequent death from prostate cancer. The morbidity subcohort data showed that decreased red blood-cell folate was significantly associated with increased events due to breast cancer, the adjusted hazard ratio per decrease of 100 mug/L was 1.96 (CI: 1.22, 3.12), women in the lowest quartile of red cell folate levels had an adjusted hazard ratio of 6.46 (CI: 1.19, 35.07) for a subsequent breast cancer event. Mortality and morbidity from colorectal or lung cancers were not associated with folate levels. CONCLUSIONS: Independent associations, assessed over periods greater than 20 years, were demonstrated between decreased folate levels and increased risks of prostate cancer mortality and breast cancer morbidity.

Longitudinal study of risk factors for habitual snoring in a general adult population: the Busselton Health Study.

BACKGROUND: The aim of this longitudinal study was to identify body size, behavioral, and respiratory risk factors for the development of habitual snoring in a general adult population. METHODS: The sample for this study comprised 967 adults aged 25 to 74 years who reported not snoring in the 1981 Busselton Health Survey and who also attended the 1994-1995 follow-up survey. Logistic regression was used to identify and quantify the effect of baseline and change risk factors for the development of habitual snoring. RESULTS: A total of 13% had become habitual snorers by 1994-1995. Male gender (odds ratio [OR], 3.5) and baseline body mass index (OR, 1.4 per 3.4 kg/m(2)) were significant predictors of habitual snoring; after accounting for these variables, no other baseline body size, behavioral, or respiratory/allergy variables were significantly related to the development of habitual snoring. However, change in body mass index over the 14-year follow-up period (OR, 1.55 per 2.3 kg/m(2)), development of asthma (OR, 2.8), and commencement of smoking (OR, 2.2) were additional significant independent risk factors for development of habitual snoring. CONCLUSIONS: This study has confirmed male gender, obesity, and weight gain as key determinants of habitual snoring, and has indicated that development of asthma and taking up smoking also play a role. Maintaining a healthy weight and not smoking are recommended lifestyle preventive strategies to reduce the risk of sleep-disordered breathing and its sequelae.

Spouse selection and environmental effects on spouse correlation in lung function measures.

PURPOSE: Concordance between spouses may be due to partner selection factors and/or the effects of marriage/environment. The extent to which partner selection factors contribute to spouse concordance has important implications for heritability studies. The aim of this study was to examine the magnitude of spouse correlation in lung function measures and its relationship to duration of marriage. METHODS: Cross-sectional and longitudinal data collected over the period 1969 to 1995 for 2615 couples from the Busselton Health Study have been analyzed using the program FISHER. RESULTS: Unadjusted correlations were around 0.45 for forced expiratory volume in 1 second (FEV1) and 0.25 for FEV1/FVC (forced vital capacity) and were reduced to 0.05 and 0.10, respectively, after adjustment for age, height, and smoking. No trend with marriage duration was apparent in both cross-sectional and longitudinal analyses but there was a significant downward trend in the correlations with age at marriage. CONCLUSIONS: The findings indicate that observed correlations in lung function measures are mostly due to partner selection factors and that partner selection factors have greater influence for couples that marry at younger ages. Family studies that aim to identify and separate genetic from other influences on lung function measures should not regard the mother-father correlation as due to common environment effects.

Correlates of habitual snoring and witnessed apnoeas in Busselton, Western Australia.

OBJECTIVE: The aim of this study was to identify potential body size, behavioural and respiratory risk factors for habitual snoring and witnessed apnoeas in a general population. METHODS: Correlates of these conditions were studied in a sample of 3,577 adults aged 25-74 years who participated in a comprehensive health survey in Busselton, Western Australia, during 1994/95. Logistic regression was used to assess associations after age and gender adjustment and also in multivariate models. RESULTS: The prevalence of both conditions was higher in men and rose with age. After controlling for age, gender and body mass index no additional body size variable remained significantly associated with witnessed apnoeas, whereas both waist-hip ratio and neck-height ratio remained significantly associated with habitual snoring. Among behavioural variables, smoking showed the strongest association, and among respiratory symptoms, asthma for habitual snoring and bronchitis for witnessed apnoeas had significant independent associations. CONCLUSIONS AND IMPLICATIONS: This study has confirmed obesity and smoking as key determinants of habitual snoring and witnessed apnoeas. It has also shown that a number of measures of obesity are independently related to habitual snoring and that asthma and bronchitis may also play a role, independently of obesity.

Evaluating the impact of repeated community-wide health surveys on cardiovascular morbidity and mortality in the busselton population.

OBJECTIVE: To evaluate the impact of repeated community-wide mass health examinations on cardiovascular mortality and hospital morbidity trends in Busselton. METHOD: Population census, hospital admission and death data were used to calculate and compare cardiovascular mortality rates from 1965 to 1998 and hospital morbidity rates from 1971 to 1998 in Busselton residents aged 40 to 84 years with the remainder of the south-west region of Western Australia. RESULTS: Among men aged 40-69 years, the calendar year trends in standardised cardiovascular mortality and morbidity ratios were relatively flat and non-significant. Among women aged 40-69 years, the mortality ratio declined significantly up to 1989 (p = 0.03) but not over the whole period (p = 0.12), and the downward trend in the morbidity ratio did not reach statistical significance (p = 0.21). Among men aged 70-84 years, both the mortality and morbidity ratios rose significantly over time, whereas among women aged 70-84 years the mortality ratios showed a flat trend and the morbidity ratios a rising trend. These increasing trends were opposite to what was expected if the surveys had a beneficial impact. CONCLUSION: This analysis of trends, while failing to demonstrate a clear benefit of repeated mass health screenings on cardiovascular event rates, also highlights the difficulties in evaluating the longer-term impact on event rates of such programs and suggests that negative conclusions should be made with caution.

Noncitrus fruits as novel dietary environmental modifiers of iron stores in people with or without HFE gene mutations.

OBJECTIVE: To investigate whether citrus fruit, noncitrus fruit, and other dietary factors act as environmental modifiers of iron status in the absence or presence of hemochromatotic HFE gene mutations. PARTICIPANTS AND METHODS: Iron studies, HFE genotypic analyses, and dietary data from a survey conducted from March 21, 1994, through December 15, 1995, were analyzed for a group of 2232 residents (1105 men, 1127 women) aged 20 to 79 years recruited from the community electoral roll of Busselton in Western Australia. Data were analyzed by linear regression analysis and analysis of covariance. RESULTS: Higher levels of fresh fruit intake (excluding citrus fruits and citrus juices) had a significant protective effect (P=.002) against high body iron status as gauged by ferritin levels in men, irrespective of HFE genotype. Consumption of 2 or more pieces of fruit per day on average reduced mean serum ferritin levels by 20% compared with average consumption of less than 1 piece of fruit per day. This effect was not observed in women. Consumption of citrus fruits and citrus juices had no significant effects in either sex. No protective effects were observed for tea consumption or any other dietary factors studied. Red meat and alcohol consumption correlated with high body iron stores (P<.05), consistent with previous studies, but did not interact with fruit with regard to effects on serum ferritin (P>.05). CONCLUSION: Noncitrus fruits are environmental modifiers of iron status independent of HFE genotype. This could have important implications for the provision of evidence-based dietary advice to patients with other iron-storage disorders.

Population-based study of the relationship between mutations in the hemochromatosis (HFE) gene and arthritis.

BACKGROUND AND AIM: Mutations in the hemochromatosis (HFE) gene are carried by one in three individuals of British Isles descent and may result in increased iron stores. These increased iron stores could potentially induce or exacerbate diseases, such as arthritis, in which iron has a role in pathogenesis. Although arthritis is a well-known association of clinically overt hereditary hemochromatosis, controversy surrounds the role of mutations in the HFE gene as risk factors for arthritis. The aim of the present study was to determine whether mutations in the HFE gene are associated with an increased prevalence of arthritis. METHODS: A population-based study was conducted in Busselton, Western Australia, of the prevalence of arthritis in 1372 individuals of British Isles descent. Participants completed a questionnaire and general physical examination. Analysis for C282Y and H63D HFE mutations was undertaken. Unadjusted and adjusted odds ratios (OR) were calculated for the relationship between HFE mutations and the prevalence of self-reported, doctor-diagnosed arthritis. RESULTS: There was no association between the presence of HFE mutations and the prevalence of self-reported, doctor-diagnosed arthritis (C282Y/wild type (WT) adjusted OR = 1.041 (95% confidence interval (CI) 0.68-1.61), H63D/WT OR = 0.76 (95% CI 0.53-1.08), C282Y/C282Y OR = 0.39 (95% CI 0.04-3.63), C282Y/H 63D OR = 0.808 (95% CI 0.27-2.42), H63D/H63D OR = 0.419 (95% CI 0.13-1.36)). Overall adjusted OR for arthritis in participants with one or more HFE mutations was 0.81 (95% CI 0.61-1.09). CONCLUSIONS: Mutations of the HFE gene are not risk factors for arthritis in populations of British Isles descent.

What can Busselton population health surveys tell us about asthma in older people?

WHAT WE NEED TO KNOW: Do the characteristics of asthma differ in people older than 55 years compared with younger people with respect to risk factors (atopy, airway hyper-responsiveness and genetic variation), smoking, lung function and other illness? How do inflammation and remodelling of airways vary with age and with duration and severity of asthma? WHAT WE NEED TO DO: Continue collecting prevalence data for asthma and its risk factors. Assess (i) period and cohort effects on asthma and its risk factors and (ii) interactions between age, smoking, severity and duration of asthma, lung function and airway responsiveness, and other concurrent disease. Measure airway responsiveness and exhaled nitric oxide to detect airway abnormalities in older people and relate this to the diagnoses of asthma and other diseases.

Effects of HFE gene mutations and alcohol on iron status, liver biochemistry and morbidity.

BACKGROUND AND AIMS: The aims of the present study were to determine: (i) whether alcohol consumption is greater in individuals with HFE mutations; and (ii) whether common HFE mutations modify the effects of alcohol on serum iron and liver biochemistry or morbidity. METHODS: The residents of the town of Busselton in Western Australia were subject to cross-sectional health surveys between 1966 and 1983. In 1994/1995 all surviving participants of the earlier surveys were invited to take part in a follow-up survey. Logistic, linear and Poisson log-linear regression analyses were performed in 1490 men and 1452 women from the 1994/1995 survey to assess the relationships between HFE mutations, alcohol, iron levels, liver biochemistry and morbidity. RESULTS: Heavy or moderate alcohol consumption was present in 7% or 36% of men and 0.5% or 12% of women, respectively. Alcohol consumption strongly influenced levels of serum ferritin and gamma glutamyl transpeptidase (GGT) and mean cell volume (MCV) in men and women but only alanine aminotransferase (ALT) levels in women. These effects were independent of HFE gene mutations. Hospital admission rates for respiratory disorders were higher in men with the C282Y mutation. CONCLUSIONS: Alcohol consumption strongly influences serum ferritin and GGT levels and MCV in men and women but only ALT levels in women, and these effects are independent of HFE mutations. HFE gene mutations do not predispose to moderate or heavy alcohol consumption. The C282Y mutation is associated with increased respiratory admission rates in men.