Objective: To examine the relationship between hospital and emergency department (ED) occupancy, as indicators of hospital overcrowding, and mortality after emergency admission. Design: Retrospective analysis of 62495 probabilistically linked emergency hospital admissions and death records. Setting: Three tertiary metropolitan hospitals between July 2000 and June 2003. Participants: All patients 18 years or older whose first ED attendance resulted in hospital admission during the study period. Main outcome measures: Deaths on days 2, 7 and 30 were evaluated against an Overcrowding Hazard Scale based on hospital and ED occupancy, after adjusting for age, diagnosis, referral source, urgency and mode of transport to hospital. Results: There was a linear relationship between the Overcrowding Hazard Scale and deaths on Day 7 (r= 0.98; 95% Cl, 0.79-1.00). An Overcrowding Hazard Scale > 2 was associated with an increased Day 2, Day 7 and Day 30 hazard ratio for death of 1.3 (95% Cl, 1.1-1.6), 1.3 (95% Cl, 1.2-1.5) and 1.2 (95% Cl, 1.1-1.3), respectively. Deaths at 30 days associated with an Overcrowding Hazard Scale > 2 compared with one of < 3 were undifferentiated with respect to age, diagnosis, urgency, transport mode, referral source or hospital length of stay, but had longer ED durations of stay (risk ratio per hour of ED stay, 1.1; 95% Cl, 1.1-1.1; P< 0.001) and longer physician waiting times (risk ratio per hour of ED wait, 1.2; 95% Cl, 1.1-1.3; P = 0.01). Conclusions: Hospital and ED overcrowding is associated with increased mortality. The Overcrowding Hazard Scale may be used to assess the hazard associated with hospital and ED overcrowding. Reducing overcrowding may improve outcomes for patients requiring emergency hospital admission.

/pdf/the-association-between-hospital-overcrowding-and-mortality-25f8gvxxc1.pdf

The association between hospital overcrowding and mortality among patients admitted via Western Australian emergency departments

Background: Previously published cohort studies in clinical populations have suggested that obstructive sleep apnea (OSA) is a risk factor for mortality associated with cardiovascular disease. However, it is unknown whether sleep apnea is an independent risk factor for all-cause mortality in a community-based sample free from clinical referral bias. Methods: Residents of the Western Australian town of Busselton underwent investigation with a home sleep apnea monitoring device (MESAM IV). OSA was quantified via the respiratory disturbance index (RDI). Mortality status was determined in 397/400 participants (99.3%) after up to 14 years (mean follow-up 13.4 years) by data matching with the Australian National Death Index and the Western Australian Death Register. Univariate analyses and multivariate Cox proportional hazards modelling were used to ascertain the association between sleep apnea and mortality after adjustment for age, gender, body mass index, mean arterial pressure, total cholesterol, high-density lipoprotein cholesterol, diabetes, and medically diagnosed angina in those free from heart attack or stroke at baseline (n = 380). Results: Among the 380 participants, 18 had moderate-severe OSA (RDI ≥15/hr, 6 deaths) and 77 had mild OSA (RDI 5 to <15/hr, 5 deaths). Moderate-to-severe OSA was independently associated with greater risk of all-cause mortality (fully adjusted hazard ratio [HR] = 6.24, 95% CL 2.01,19.39) than non-OSA (n = 285, 22 deaths). Mild OSA (RDI 5 to <15/hr) was not an independent risk factor for higher mortality (HR = 0.47, 95% CL 0.17, 1.29). Conclusions: Moderate-to-severe sleep apnea is independently associated with a large increased risk of all-cause mortality in this community-based sample.

Sleep Apnea as an Independent Risk Factor for All-Cause Mortality : The Busselton Health Study. Commentary

OBSTRUCTIVE SLEEP APNEA (OSA) IS CHARACTERIZED BY REPETITIVE UPPER AIRWAY CLOSURE DURING SLEEP RESULTING IN REPEATED REVERSIBLE blood oxygen desaturation and fragmented sleep. OSA has been associated with a range of pathophysiological changes that impair cardiovascular function,1 including increased blood inflammatory markers and repeated rises in blood pressure during sleep. There is increasing evidence that OSA promotes the development of hypertension, stroke, myocardial infarction and premature death.2 However, because OSA is strongly associated with obesity and thus also with many other obesity-related diseases, it has been difficult to produce clear evidence that these associations are caused by sleep apnea and not other established causes.

Better understanding of the association between OSA and mortality risk has major public health importance.3 A number of studies have shown that approximately 25% of middle-aged men and 9% of middle-aged women stop breathing during sleep ≥ 5 times per hour.4–6 Given that the major modifiable risk factor for OSA is obesity it is likely that the prevalence of OSA is increasing.7 Thus, as a very common condition, even modest effects of sleep apnea on morbidity and mortality would be important.3

Previous reports that have independently linked OSA to mortality have all been based on patients referred to sleep clinics.8–14 Two of the most recent and frequently cited of these studies indicated that severe sleep apnea, compared to no sleep apnea, was an independent risk factor for cardiovascular mortality (odds ratio 2.87, 95% CL 1.17, 7.51)12; the other study found that sleep apnea, compared to no sleep apnea, was an independent risk factor for a composite endpoint of all-cause mortality or incident stroke (hazard ratio 1.97, 95% CL 1.12, 3.48).11 However, as these were not community recruited participants they might have been subject to a clinical referral bias that might have given a false impression of the size or significance of the true association with mortality in the community. The choice of composite or restricted mortality endpoints also failed to rule out that sleep apnea might have had some unexpected beneficial effect that reduced mortality from other causes. Data from a community-based cohort, free from clinical referral bias, would thus be useful to determine whether sleep apnea is an independent risk factor for all-cause mortality in middle-aged people.

The community of Busselton in Western Australia has been the subject of cross-sectional and follow-up health surveys since 1966.15–17 We aimed to investigate whether sleep apnea is an independent risk factor for all-cause mortality in a sample of Busselton Health Study participants recruited in 1990 to determine the community prevalence of sleep apnea.4

Sleep Apnea as an Independent Risk Factor for All-Cause Mortality: The Busselton Health Study

Objective To examine the mortality experience of psychiatric patients in Western Australia compared with the general population. Design Population based study. Setting Western Australia, 1985-2005. Participants Psychiatric patients (292 585) registered with mental health services in Western Australia. Main outcome measures Trends in life expectancy for psychiatric patients compared with the Western Australian population and causes of excess mortality, including physical health conditions and unnatural causes of death. Results When using active prevalence of disorder (contact with services in previous five years), the life expectancy gap increased from 13.5 to 15.9 years for males and from 10.4 to 12.0 years for females between 1985 and 2005. Additionally, 77.7% of excess deaths were attributed to physical health conditions, including cardiovascular disease (29.9%) and cancer (13.5%). Suicide was the cause of 13.9% of excess deaths. Conclusions Despite knowledge about excess mortality in people with mental illness, the gap in their life expectancy compared with the general population has widened since 1985. With most excess deaths being due to physical health conditions, public efforts should be directed towards improving physical health to reduce mortality in people with mental illness, in addition to ongoing efforts to prevent suicide.

https://www.bmj.com/content/bmj/346/bmj.f2539.full.pdf

The gap in life expectancy from preventable physical illness in psychiatric patients in Western Australia: Retrospective analysis of population based registers

The Rochester Epidemiology Project (REP) has maintained a comprehensive medical records linkage system for nearly half a century for almost all persons residing in Olmsted County, Minnesota. Herein, we provide a brief history of the REP before and after 1966, the year in which the REP was officially established. The key protagonists before 1966 were Henry Plummer, Mabel Root, and Joseph Berkson, who developed a medical records linkage system at Mayo Clinic. In 1966, Leonard Kurland established collaborative agreements with other local health care providers (hospitals, physician groups, and clinics [primarily Olmsted Medical Center]) to develop a medical records linkage system that covered the entire population of Olmsted County, and he obtained funding from the National Institutes of Health to support the new system. In 1997, L. Joseph Melton III addressed emerging concerns about the confidentiality of medical record information by introducing a broad patient research authorization as per Minnesota state law. We describe how the key protagonists of the REP have responded to challenges posed by evolving medical knowledge, information technology, and public expectation and policy. In addition, we provide a general description of the system; discuss issues of data quality, reliability, and validity; describe the research team structure; provide information about funding; and compare the REP with other medical information systems. The REP can serve as a model for the development of similar research infrastructures in the United States and worldwide.

History of the Rochester Epidemiology Project: Half a Century of Medical Records Linkage in a US Population

https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.1467-842X.1999.tb01297.x

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

Objectives: The report describes the strategic design, steps to full implementation and outcomes achieved by the Western Australian Data Linkage System (WADLS), instigated in 1995 to link up to 40 years of data from over 30 collections for an historical population of 3.7 million. Staged development has seen its expansion, initially from a linkage key to local health data sets, to encompass links to national and local health and welfare data sets, genealogical links and spatial references for mapping applications. Applications: The WADLS has supported over 400 studies with over 250 journal publications and 35 graduate research degrees. Applications have occurred in health services utilisation and outcomes, aetiologic research, disease surveillance and needs analysis, and in methodologic research. Benefits: Longitudinal studies have become cheaper and more complete; deletion of duplicate records and correction of data artifacts have enhanced the quality of information assets; data linkage has conserved patient privacy; community machinery necessary for organised responses to health and social problems has been exercised; and the commercial return on research infrastructure investment has exceeded 1000%. Most importantly, there have been unbiased contributions to medical knowledge and identifiable advances in population health arising from the

/pdf/a-decade-of-data-linkage-in-western-australia-strategic-51tfzot74c.pdf

A decade of data linkage in Western Australia: strategic design, applications and benefits of the WA data linkage system

Validation of linked administrative data on end-stage renal failure: application of record linkage to a 'clinical base population'.

Study objective?To measure the trend, pattern, and cost of time spent in hospital during the last year of life in Western Aus tralia and to identify trends in the place of death. The results were compared with those reported from the Oxford Record Linkage Study. Design?Mortality records for those aged 65 years and over were linked to inpatient hospital morbidity records with a date of separation within one year before death. Comparative inpatient resource utilisa tion was estimated using ANDRG 3.0 cost weights for Australian public hospitals. Setting?Western Australia. Participants?All 68 875 persons aged 65 years and over who died between 1 January 1985 and 31 December 1994. Main results?Increasing proportions of all age groups (65-74, 75-84, and 85+ years) were admitted to hospital at least once in the year before death during 1985 94, but the chance of admission decreased with age. There was a trend towards a greater number of shorter admissions per person. Total bed days per person showed no significant increase, except at ages 65-74 years. Total inpatient resource utilis ation during the last year of life was lowest and remained constant in those aged 85 years and over, while increasing gradually (3.7% per annum) in the younger elderly. The Western Australian population spent more time in hospital in the last year of life at ages 65-74 years, but the advanced elderly spent less time in hospital, when compared with the Oxford Region. Conclusions?Recent gains in life expect ancy and higher per capita health ex penditure have not been accompanied by more time spent in hospital during the last year of life at ages 75+ years. International Table 1 Proportion of age groups admitted to hospital at least once in the year before death in 1994, broken down by total number of bed days

A. John Bass

Papers

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

A decade of data linkage in Western Australia: strategic design, applications and benefits of the WA data linkage system

Validation of linked administrative data on end-stage renal failure: application of record linkage to a 'clinical base population'.

Hospitalisation of the elderly during the last year of life: an application of record linkage in Western