Mobile Australians: a moving target for epidemiologists

Long-term survival among OHCA patients who survive to 30 days: Does initial arrest rhythm remain a prognostic determinant?

OBJECTIVE

To determine whether initial cardiac arrest rhythm remains a prognostic determinant in longer term OHCA survival.

METHODS

The St John Western Australian OHCA database was used to identify adults who survived for at least 30 days after an OHCA of presumed medical aetiology, in the Perth metropolitan area between 1998 and 2017. Associations between 8-year OHCA survival and variables of interest were analysed using a Multi-Resolution Hazard (MRH) estimator model with 1-year intervals.

RESULTS

Of the 871 OHCA patients who survived 30 days, 718 (82%) presented with a shockable initial arrest rhythm and 153 (18%) presented with a non-shockable rhythm. Compared to patients with initial shockable arrests, patients with non-shockable arrests experienced increased mortality in the first (HR 3.33, 95% CI 2.12-5.32), second (HR 2.58, 95% CI 1.22-5.15), third (HR 2.21, 95% CI 1.02-4.42) and fourth (HR 2.21, 95% CI 1.02-4.42) year post arrest; however, in subsequent years the initial arrest rhythm ceased to be significantly associated with survival. The overall 8-year survival estimates after adjustment for peri-arrest factors (as potential confounders) were 87% (95% CI 77-93%) for shockable arrests and 73% (95% CI 55-86%) for non-shockable arrests.

CONCLUSIONS

Patients with non-shockable (as opposed to shockable) initial arrest rhythms experienced higher mortality in the first 4-years following their OHCA; however, after four years the initial arrest rhythm ceased to be associated with survival.

Body Mass Index and Vascular Disease in Men Aged 65 Years and Over: HIMS (Health In Men Study)

BACKGROUND

Understanding the relationship between body mass index (BMI) and vascular disease at older age has become increasingly important in the many countries where both average age and BMI are rising.

METHODS AND RESULTS

In this prospective cohort study, 12 203 men (aged ≥65) were recruited in 1996-1999 from the general population in Perth, Australia. To limit reverse causality, analyses excluded those with past vascular disease and the first 4 years of follow-up. During a further 8 (SD3) years of follow-up, there were 1136 first-ever major vascular events (nonfatal myocardial infarction, nonfatal stroke, or death from any vascular cause). Cox regression (adjusted for age, education, and smoking) related BMI at recruitment to incidence of major vascular events. At ages 65 to 94, the lowest risk of major vascular events was at ≈ 22.5 to 25 kg/m². In the higher BMI range (≥25 kg/m²), 5 kg/m² higher BMI was associated with 33% higher risk of major vascular events (hazard ratio, 1.33 [95% confidence interval, 1.18-1.49]): 24% higher risk of ischemic heart disease (1.24 [1.06-1.46]); 34% higher risk of stroke (1.34 [1.11-1.63]); and 78% higher risk of other vascular death (1.78 [1.32-2.41]). In the lower BMI range, there were fewer events and no strong evidence of an association (hazard ratio per 5 kg/m² higher BMI, 0.82 [95% confidence interval, 0.61-1.12]).

CONCLUSIONS

In this population of older men, risk of major vascular events was lowest at ≈ 22.5 to 25 kg/m². Above this range, BMI was strongly related to incidence of major vascular events, with each 5 kg/m² higher BMI associated with ≈30% higher risk.

Trends in the incidence and prevalence of cardiac pacemaker insertions in an ageing population

OBJECTIVES

To determine contemporary population estimates of the prevalence of cardiac permanent pacemaker (PPM) insertions.

METHODS

A population-based observational study using linked hospital morbidity and death registry data from Western Australia (WA) to identify all incident cases of PPM insertion for adults aged 18 years or older. Prevalence rates were calculated by age and sex for the years 1995-2009 for the WA population.

RESULTS

There were 9782 PPMs inserted during 1995-2009. Prevalence rose across the study period, exceeding 1 in 50 among people aged 75 or older from 2005. This was underpinned by incidence rates which rose with age, being highest in those 85 years or older; over 500/100 000 for men throughout, and over 200/100 000 for women. Rates for patients over 75 were more than double the rates for those aged 65-74 years. Women were around 40% of cases overall. The use of dual-chamber and triple-chamber pacing increased across the study period. A cardiac resynchronisation defibrillator was implanted for 58% of patients treated with cardiac resynchronisation therapy.

CONCLUSIONS

Rates of insertion and prevalence of PPM continue to rise with the ageing population in WA. As equilibrium has probably not been reached, the demand for pacing services in similarly well-developed economies is likely to continue to grow.

A longitudinal study of foot ulceration and its risk factors in community-based patients with type 2 diabetes: the Fremantle Diabetes Study

AIMS

To determine the prevalence and associates of foot ulcer, and the subsequent incidence and predictors of first-ever hospitalisation for this complication, in well-characterised community-based patients with type 2 diabetes.

METHODS

Baseline foot ulceration was ascertained in 1296 patients (mean age 64 years, 48.6% male, median diabetes duration 4.0 years) recruited to the longitudinal Fremantle Diabetes Study between 1993 and 1996. Incident hospitalisation for foot ulceration was monitored through validated data linkage until end-December 2010.

RESULTS

At baseline, 16 participants (1.2%) had a foot ulcer which was independently associated with intermittent claudication, peripheral sensory neuropathy (PSN) and diabetes duration (P≤0.01). The incidence of hospitalisation for this complication in those without prior/prevalent foot ulceration was 5.21 per 1000 patient-years. This rate and other published data suggest that 1 in 7-10 foot ulcers require hospitalisation. In a Cox proportional hazards model, intermittent claudication and PSN were significant independent predictors of time to admission with foot ulceration, in addition to retinopathy, cerebrovascular disease, HbA1c, alcohol consumption, renal impairment, peripheral arterial disease and pulse pressure (P≤0.038).

CONCLUSIONS

These data confirm PSN as an important risk factor for foot ulceration but, in contrast to some other studies, peripheral arterial disease was also a major independent contributor. Associations between hospitalisation for foot ulcer and both retinopathy and raised pulse pressure suggest a role for local microvascular dysfunction, while alcohol may have non-neuropathic toxic effects on skin/subcutaneous structures. The multifactorial nature of foot ulceration complicating type 2 diabetes may have implications for its management.

Incidence and predictors of all-cause and site-specific cancer in type 2 diabetes: the Fremantle Diabetes Study

OBJECTIVE

To explore the relationship between diabetes and cancer.

DESIGN

The Fremantle Diabetes Study (FDS) was a community-based longitudinal observational study of 1426 subjects, 1294 of which had type 2 diabetes.

METHODS

The FDS type 2 cohort and four age-, sex- and postcode-matched controls per case were followed for cancer events from 1993 until mid-2010 and incidence rate ratios (IRRs) were calculated. Competing risks proportional hazards models generated risk factors for incident cancers in the diabetic group.

RESULTS

There were 309 first cancers over 13 051 patient-years, or 2368 (95% confidence interval (95% CI) 2111-2647)/100 000 patient-years in the diabetes patients vs 1131 over 60 324 patient-years (1875 (1769-1987)/100 000 patient-years) in the controls. For those aged ≥45 years, the risk of all-cause cancer was elevated in type 2 diabetic men (IRRs 1.23, 95% CI 1.04-1.45) and women (1.30, 1.06-1.59). The incidence of colorectal cancer was increased (1.36, 1.01-1.82), especially in diabetic men aged 75-84 years (2.14, 1.22-3.64). Age at diabetes diagnosis (sub-hazard ratio 1.05, 1.02-1.09), calcium channel blocker therapy (2.37, 1.39-4.06), recent exercise (2.11, 1.06-4.20) and serum total cholesterol (0.68, 0.52-0.88) increased colorectal cancer risk. Pancreatic cancer was also more frequent in the diabetic patients (IRR 2.26, 1.20-4.10). Diabetic men and women had similar risks of prostate and breast cancer to those of controls (0.83, 0.59-1.14 and 0.86, 0.52-1.36).

CONCLUSIONS

Type 2 diabetes is associated with a moderately increased cancer risk in well-characterised community-based patients, especially pancreatic cancer and colorectal cancer in older men. Recommended cancer screening should be considered as part of routine diabetes management.

Body adiposity in later life and the incidence of dementia: the health in men study

Objective

To determine if adiposity in later life increases dementia hazard.

Methods

Cohort study of 12,047 men aged 65–84 years living in Perth, Australia. Adiposity exposures were baseline body mass index (BMI), waist circumference (WC) and waist-to-hip ratio (WHR). We used the Western Australian Data Linkage System (WADLS) to establish the presence of new cases of dementia between 1996 and 2009 according to the International Classification of Diseases (ICD). Crude and adjusted hazard ratio (HR, 95% confidence interval, 95%CI) of dementia for each adiposity marker was calculated using Cox regression models. Other measured factors included age, marital status, education, alcohol use, smoking, diet, physical activity, and prevalent hypertension, diabetes, dyslipidaemia and cardiovascular disease.

Results

Compared with men with BMI<25, participants with BMI between 25–30 had lower adjusted HR of dementia (HR = 0.82, 95% CI = 0.70–0.95). The HR of dementia for men with BMI≥30 was comparable to men with BMI<25 (HR = 0.82, 95%CI = 0.67–1.01). Waist circumference showed no obvious association with dementia hazard. Men with WHR≥0.9 had lower adjusted HR of dementia than men with WHR <0.9 (HR = 0.82, 95%CI = 0.69–0.98). We found a “J” shape association between measures of obesity and the hazard of dementia, with the nadir of risk being in the overweight range of BMI and about 1 for WHR.

Conclusions

Higher adiposity is not associated with incident dementia in this Australian cohort of older men. Overweight men and those with WHR≥0.9 have lower hazard of dementia than men with normal weight and with WHR<0.9.

Changes in Case-Mix and Outcomes of Critically Ill Patients in an Australian Tertiary Intensive Care Unit

Critical care service is expensive and the demand for such service is increasing in many developed countries. This study aimed to assess the changes in characteristics of critically ill patients and their effect on long-term outcome. This cohort study utilised linked data between the intensive care unit database and state-wide morbidity and mortality databases. Logistic and Cox regression was used to examine hospital survival and five-year survival of 22,298 intensive care unit patients, respectively. There was a significant increase in age, severity of illness and Charlson Comorbidity Index of the patients over a 16-year study period. Although hospital mortality and median length of intensive care unit and hospital stay remained unchanged, one- and five-year survival had significantly improved with time, after adjusting for age, gender, severity of illness, organ failure, comorbidity, ‘new’ cancer and diagnostic group. Stratified analyses showed that the improvement in five-year survival was particularly strong among patients admitted after cardiac surgery (P=0.001). In conclusion, although critical care service is increasingly being provided to patients with a higher severity of acute and chronic illnesses, long-term survival outcome has improved with time suggesting that critical care service may still be cost-effectiveness despite the changes in case-mix.

Serum uric acid does not predict cardiovascular or all-cause mortality in type 2 diabetes: the Fremantle Diabetes Study

AIMS/HYPOTHESIS

To determine whether serum uric acid: (1) is associated with cardiovascular disease (CVD) death and/or all-cause mortality in type 2 diabetes; and (2) consistent with published data, predicts these outcomes in older patients and those of southern European ethnicity.

METHODS

We studied those 1,268 (98%) of 1,294 type 2 participants in the observational Fremantle Diabetes Study who had a fasting serum uric acid measured at baseline. Mortality data were collected over a mean (+/-SD) 10.3 +/- 3.9 years. Cox proportional hazards modelling was used to determine independent baseline predictors of CVD and all-cause death including fasting serum uric acid as a continuous variable and quartiles.

RESULTS

During follow up, 525 deaths occurred (41.4% of the cohort) of which 271 (51.6%) were attributed to CVD. In univariate analyses, patients in the highest uric acid quartile had the greatest CVD and all-cause mortality (p = 0.007 and p = 0.001). After adjustment for significant variables in the most parsimonious model, baseline serum uric acid was not an independent associate of CVD or all-cause mortality whether entered as a continuous variable (HR 1.11 [95% CI 0.96-1.27] and 1.10 [95% CI 0.98-1.22] for a 0.1 mmol/l increase, respectively) or as quartiles (p > 0.10). Analyses of 638 patients >65 years of age and 231 of southern European ethnicity produced similar results.

CONCLUSIONS/INTERPRETATION

Serum uric acid was not an independent predictor of CVD or all-cause mortality in our community-based type 2 patients. Fasting serum uric acid concentrations do not appear to be prognostically useful in type 2 diabetes.

Aspirin is associated with reduced cardiovascular and all-cause mortality in type 2 diabetes in a primary prevention setting: the Fremantle Diabetes study

OBJECTIVE

To determine whether regular aspirin use (> or =75 mg/day) is independently associated with cardiovascular disease (CVD) and all-cause mortality in community-based patients with type 2 diabetes and no history of CVD.

RESEARCH DESIGN AND METHODS

Of the type 2 diabetic patients recruited to the longitudinal observational Fremantle Diabetes Study, 651 (50.3%) with no prior CVD history at entry between 1993 and 1996 were followed until death or the end of June 2007, representing a total of 7,537 patient-years (mean +/- SD 11.6 +/- 2.9 years). Cox proportional hazards modeling was used to determine independent baseline predictors of CVD and all-cause mortality including regular aspirin use.

RESULTS

There were 160 deaths (24.6%) during follow-up, with 70 (43.8%) due to CVD. In Kaplan-Meier survival analysis, there was no difference in either CVD or all-cause mortality in aspirin users versus nonusers (P = 0.52 and 0.94, respectively, by log-rank test). After adjustment for significant variables in the most parsimonious Cox models, regular aspirin use at baseline independently predicted reduced CVD and all-cause mortality (hazard ratio [HR] 0.30 [95% CI 0.09-0.95] and 0.53 [0.28-0.98[, respectively; P < or = 0.044). In subgroup analyses, aspirin use was independently associated with reduced all-cause mortality in those aged > or =65 years and men.

CONCLUSIONS

Regular low-dose aspirin may reduce all-cause and CVD mortality in a primary prevention setting in type 2 diabetes. All-cause mortality reductions are greatest in men and in those aged > or =65 years. The present observational data support recommendations that aspirin should be used in primary CVD prevention in all but the lowest risk patients.

Effect of an episode of critical illness on subsequent hospitalisation: a linked data study

Healthcare utilisation can affect quality of life and is important in assessing the cost-effectiveness of medical interventions. A clinical database was linked to two Australian state administrative databases to assess the difference in incidence of healthcare utilisation of 19,921 patients who survived their first episode of critical illness. The number of hospital admissions and days of hospitalisation per patient-year was respectively 150% and 220% greater after than before an episode of critical illness (assessed over the same time period). This was the case regardless of age or type of surgery (i.e. cardiac vs non-cardiac). After adjusting for the ageing effect of the cohort as a whole, there was still an unexplained two to four-fold increase in hospital admissions per patient-year after an episode of critical illness. We conclude that an episode of critical illness is a robust predictor of subsequent healthcare utilisation.

Landmark survival as an end-point for trials in critically ill patients--comparison of alternative durations of follow-up: an exploratory analysis

Introduction

Interventional ICU trials have followed up patients for variable duration. However, the optimal duration of follow-up for the determination of mortality endpoint in such trials is uncertain. We aimed to determine the most logical and practical mortality end-point in clinical trials of critically ill patients.

Methods

We performed a retrospective analysis of prospectively collected data involving 369 patients with one of the three specific diagnoses (i) Sepsis (ii) Community acquired pneumonia (iii) Non operative trauma admitted to the Royal Perth Hospital ICU, a large teaching hospital in Western Australia (WA cohort). Their in-hospital and post discharge survival outcome was assessed by linkage to the WA Death Registry. A validation cohort involving 4609 patients admitted during same time period with identical diagnoses from 55 ICUs across Australia (CORE cohort) was used to compare the patient characteristics and in-hospital survival to look at the Australia-wide applicability of the long term survival data from the WA cohort.

Results

The long term outcome data of the WA cohort indicate that mortality reached a plateau at 90 days after ICU admission particularly for sepsis and pneumonia. Mortality after hospital discharge before 90 days was not uncommon in these two groups. Severity of acute illness as measured by the total number of organ failures or acute physiology score was the main predictor of 90-day mortality. The adjusted in-hospital survival for the WA cohort was not significantly different from that of the CORE cohort in all three diagnostic groups; sepsis (P = 0.19), community acquired pneumonia (P = 0.86), non-operative trauma (P = 0.47).

Conclusions

A minimum of 90 days follow-up is necessary to fully capture the mortality effect of sepsis and community acquired pneumonia. A shorter period of follow-up time may be sufficient for non-operative trauma.

Chronic complications and mortality in community-based patients with latent autoimmune diabetes in adults: the Fremantle Diabetes Study

AIMS

To compare (i) the prevalence and incidence of chronic complications and (ii) cardiac and all-cause mortality in community-based patients with latent autoimmune diabetes in adults (LADA) with those in Type 2 diabetic patients without antibodies to glutamic acid decarboxylase (GAD).

METHODS

Of the 1294 patients with clinically-defined Type 2 diabetes recruited to the longitudinal, observational Fremantle Diabetes Study between 1993 and 1996, 1255 (97%) had GAD antibodies measured at baseline. Complications were ascertained using standard criteria in patients returning for annual assessments until November 2001. Data on hospital admissions and mortality were available to the end of June 2006. Cox proportional hazards modelling was used to determine independent predictors of first occurrence of complications and cardiac and all-cause mortality.

RESULTS

Forty-five (3.6%) subjects had LADA. Compared with the GAD antibody-negative patients, they had a similar prevalence and incidence of coronary heart (P = 0.48 and 0.80, respectively) and cerebrovascular (P = 0.64 and 0.29) disease and cardiac and all-cause mortality (P = 0.62 and 0.81, respectively). There was also a similar prevalence and incidence of retinopathy (P = 0.22 and 0.64, respectively) and neuropathy (P = 0.25 and 0.95), but microalbuminuria was less frequent both at baseline and during follow-up in the LADA subgroup in unadjusted models (P = 0.046) and after adjustment for other risk factors (P = 0.014 and 0.013).

CONCLUSIONS

Except for a lower prevalence and incidence of nephropathy, LADA patients have a similar risk of complications and death to patients with clinically-diagnosed Type 2 diabetes without GAD antibodies. Cardiovascular risk factor management in LADA should, therefore, be as intensive as that for GAD antibody-negative patients.

Metformin and lactic acidosis in an Australian community setting: the Fremantle Diabetes Study

OBJECTIVE

To determine the incidence of lactic acidosis in community-based patients with type 2 diabetes, with special reference to metformin therapy.

DESIGN

Substudy within a longitudinal observational study, the Fremantle Diabetes Study (FDS).

PARTICIPANTS AND SETTING

1279 patients from a postcode-defined population of 120 097 people in Western Australia.

MAIN OUTCOME MEASURES

Confirmed hospitalisation with lactic acidosis identified through the WA Data Linkage System during two periods: (1) from study entry, between 1993 and 1996, and study close in November 2001; and (2) from study entry to 30 June 2006.

RESULTS

At entry, 33.3% of patients were metformin-treated, and 23.1% of these had one or more contraindications to metformin (55.1% and 38.0%, respectively, after 5 years' follow-up). Five confirmed cases of lactic acidosis were identified during 12 466 patient-years of observation; all had at least one other potential cause, such as cardiogenic shock or renal failure. From study entry to close, the incidence was 0/100,000 patient-years in both metformin-treated and non-metformin-treated patients. Between study entry and 30 June 2006, incidence was 57/100,000 patient-years (95% CI, 12-168) in metformin-treated patients and 28/100,000 patient-years (95% CI, 3-100) in the non-metformin-treated group, an incidence rate difference of -30 (-105 to 46) (P=0.4).

CONCLUSION

The incidence of lactic acidosis in patients with type 2 diabetes is low but increases with age and duration of diabetes, as cardiovascular and renal causes become more prevalent. Metformin does not increase the risk of lactic acidosis, even when other recognised precipitants are present.

Determinants of long-term survival after intensive care

OBJECTIVE

To identify prognostic determinants of long-term survival for patients treated in intensive care units (ICUs) who survived to hospital discharge.

DESIGN

An ICU clinical cohort linked to state-wide hospital records and death registers.

SETTING AND PATIENTS

Adult patients admitted to a 22-bed ICU at a major teaching hospital in Perth, Western Australia, between 1987 and 2002 who survived to hospital discharge (n = 19,921) were followed-up until December 31, 2003.

MEASUREMENTS

The main outcome measures are crude and adjusted survival.

MAIN RESULTS

The risk of death in the first year after hospital discharge was high for patients who survived the ICU compared with the general population (standardized mortality rate [SMR] at 1 yr = 2.90, 95% confidence interval [CI] 2.73-3.08) and remained higher than the general population for every year during 15 yrs of follow up (SMR at 15 yrs = 2.01, 95% CI 1.64-2.46). Factors that were independently associated with survival during the first year were older age (hazard ratio [HR] = 4.09; 95% CI 3.20-5.23), severe comorbidity (HR = 5.23; 95% CI 4.25-6.43), ICU diagnostic group (HR range 2.20 to 8.95), new malignancy (HR = 4.60; 95% CI 3.68-5.76), high acute physiology score on admission (HR = 1.55; 95% CI 1.23-1.96), and peak number of organ failures (HR = 1.51; 95% CI 1.11-2.04). All of these factors were independently associated with subsequent survival for those patients who were alive 1 yr after discharge from the hospital with the addition of male gender (HR = 1.17; 95% CI 1.10-1.25) and prolonged length of stay in ICU (HR = 1.42; 95% CI 1.29-1.55).

CONCLUSIONS

Patients who survived an admission to the ICU have worse survival than the general population for at least 15 yrs. The factors that determine long-term survival include age, comorbidity, and primary diagnosis. Severity of illness was also associated with long-term survival and this suggests that an episode of critical illness, or its treatment, may shorten life-expectancy.

Incidence and determinants of carpal tunnel decompression surgery in type 2 diabetes: the Fremantle Diabetes Study

To examine the incidence and predictors of carpal tunnel decompression (CTD) in community-based patients with type 2 diabetes, we studied 1,284 type 2 diabetic participants (mean +/- SD age 64.1 +/- 6.1 years, 49.1% male) in the longitudinal observational Fremantle Diabetes Study who had no history of CTD. A total of 67 participants (5.8%) had a first CTD during 12,109 years (mean 9.4 +/- 3.7) of follow-up, an incidence of 5.5 per 1,000 patient-years. This was at least 4.2 times the incidence in the general population (P < 0.001). In Cox proportional hazards analysis, significant independent determinants of first-ever CTD were higher BMI, taking lipid-lowering medication, and being in a stable relationship (P <or= 0.021). The crude incidence of first CTD is increased in type 2 diabetes and is associated with obesity and sociodemographic/treatment factors that could indicate treatment-seeking behavior including CTD in symptomatic patients.

Does self-monitoring of blood glucose improve outcome in type 2 diabetes? The Fremantle Diabetes Study

AIMS/HYPOTHESIS

To assess whether self-monitoring of blood glucose (SMBG) is an independent predictor of improved outcome in a community-based cohort of type 2 diabetic patients.

MATERIALS AND METHODS

We used longitudinal data from (1) 1,280 type 2 diabetic participants in the observational Fremantle Diabetes Study (FDS) who reported SMBG and diabetes treatment status at study entry (1993-1996), and (2) a subset of 531 participants who attended six or more annual assessments (referred to as the 5-year cohort). Diabetes-related morbidity, cardiac death and all-cause mortality were ascertained at each assessment, supplemented by linkage to the Western Australian Data Linkage System.

RESULTS

At baseline, 70.2% (898 out of 1,280) of type 2 patients used SMBG. During 12,491 patient-years of follow-up (mean 9.8+/-3.5 years), 486 (38.0%) type 2 participants died (196 [15.3%] from cardiac causes). SMBG was significantly less prevalent in those who died during follow-up than in those who were still alive at the end of June 2006 (65.4 vs 73.0%, p=0.005). In Cox proportional hazards modelling, after adjustment for confounding and explanatory variables, SMBG was not independently associated with all-cause mortality, but was associated with a 79% increased risk of cardiovascular mortality in patients not treated with insulin. For the 5-year cohort, time-dependent SMBG was independently associated with a 48% reduced risk of retinopathy.

CONCLUSIONS/INTERPRETATION

SMBG was not independently associated with improved survival. Inconsistent findings relating to the association of SMBG with cardiac death and retinopathy may be due to confounding, incomplete covariate adjustment or chance.

Predictors, consequences and costs of diabetes-related lower extremity amputation complicating type 2 diabetes: the Fremantle Diabetes Study

AIMS/HYPOTHESIS

The aims of this study were to assess the incidence, predictors, consequences, and inpatient cost of lower extremity amputation (LEA) in a community-based cohort of type 2 diabetic patients.

METHODS

Between 1993 and 1996, 1,294 patients with type 2 diabetes were recruited to the longitudinal, observational Fremantle Diabetes Study. LEAs and mortality from cardiac causes were monitored until 30 June 2005. Inpatient costs (in Australian dollars in year 2000), derived using a case-mix approach, were available for the period from 1 July 1993 to 30 June 2000.

RESULTS

During follow-up 44 patients without LEA at baseline had a first-ever diabetes-related LEA, an incidence of 3.8 per 1,000 patient-years. Independent predictors of first-ever LEA included foot ulceration (hazard ratio [95% CI]: 5.56 [1.24-25.01]), an ankle brachial index < or =0.90 (2.21 [1.11-4.42]), HbA(1c) (increase of 1%: 1.30 [1.10-1.54]) and neuropathy (2.65 [1.30-5.44]). The risk of cardiac death was significantly increased in patients with LEA at baseline, although this was not an independent risk factor. The median (interquartile range) inpatient cost per LEA admission was 12,485 Australian dollars (6,037 Australian dollars-24,415 Australian dollars), with a median length of stay of 24 (10-43) days.

CONCLUSIONS/INTERPRETATION

First-ever LEAs in type 2 patients were associated with poor glycaemic control, foot ulceration and evidence of microvascular and macrovascular disease. Patients with LEA were at increased risk of cardiac death. LEAs contribute disproportionately to diabetes-related inpatient costs.

Data linkage enables evaluation of long-term survival after intensive care

Outcomes of intensive care are important to the patient and for assessment of benefit. Short-term outcomes after critical illness are well described, but less is known about long-term outcomes. This study describes the use of data linkage, combining intensive care unit (ICU) clinical data with administrative morbidity and mortality data, to assess long-term outcomes after treatment in ICU. The hospital-based cohort study was conducted in a 22-bed general ICU in a metropolitan teaching hospital. All patient admissions admitted to ICU from 1 January 1987 to 31 December 2002 were included. The prospective ICU clinical database with patient demographics, ICU diagnoses, severity of illness, daily assessment of organ failures and common daily treatments used was linked using probabilistic methods to the state-wide hospital morbidity and mortality databases to describe long-term survival. There were 26,019 ICU admissions (22,980 patients) with 25,972 records (99.8%) linked to a hospitalization event that included the index ICU admission. Unadjusted survival was 84.7% at 1 year decreasing progressively to 50.7% at 15 years. Age, type of admission, severity of illness (measured by Acute Physiologic and Chronic Health Evaluation (APACHE) II and the presence of organ failure), ICU length of stay, comorbidity (Chronic Health Evaluation and Charlson comorbidity index) and ICU admission diagnosis, were all associated with survival at 1, 3, 5, 10, and 15 year follow-up (P<0.001 at all time points). Linkage of clinical and administrative data provides a feasible method for ascertaining long-term survival after critical illness. Age, admission severity of illness, diagnosis and comorbidity influenced long-term unadjusted survival.

Return to Work After Coronary Artery Bypass Surgery in a Population of Long-Term Survivors

BACKGROUND

Return to paid employment may be facilitated by coronary artery bypass graft (CABG) surgery. We assessed work status in a population-based study of long-term outcomes of CABG.

AIM

To determine the association between returning to work after CABG and clinical and socio-demographic factors.

METHODS

A postal survey of 2,500 randomly selected patients 6-20 years post-CABG. The outcomes assessed were work status in the year before and after CABG and health-related quality of life (HRQOL) measured with SF-36.

RESULTS

Response was 82% (n = 2,061). Employment fell from 56% in the year prior to CABG to 42% in the year after. Workers in 'blue-collar' occupations were more likely to reduce their work status than those in 'white collar' occupations (46% versus 29%, p < 0.001). Independent predictors of reducing employment were increasing age (9% per year, 99% CI: 1.06-1.11, p < 0.001), 'blue-collar' versus 'white collar' occupation (OR: 2.1, 99% CI: 1.4-3.1) and female sex (OR: 2.1, 99% CI: 1.1-3.6). HRQOL among participants under 60 years of age at follow-up was better for those who returned to work after CABG surgery.

CONCLUSION

CABG surgery is followed by a net loss to paid employment of working age patients which increases with age, and is more likely for those in blue-collar occupations and women.

Lifestyle still predicts mortality in older men with established vascular disease

BACKGROUND

It is uncertain whether accepted associations between health behaviors and mortality are pertinent to elderly people. No previous studies have examined the patterns of lifestyle in elderly men with and without clinically evident vascular disease by using a lifestyle score to predict survival.

METHODS

We measured prevalence of a healthy lifestyle (four or more healthy behaviors out of eight) and examined survival in 11,745 men aged 65-83 years participating in a randomized population-based trial of screening for abdominal aortic aneurysm in Perth, Western Australia. After stratifying participants into five groups according to history and symptoms of vascular disease, we compared survival of men in each subgroup with that of 'healthy' men with no history or symptoms of vascular disease.

RESULTS

Invitations to screening produced a corrected response of 70.5%. After adjusting for age and place of birth, having an unhealthy lifestyle was associated with an increase of 20% in the likelihood of death from any cause within 5 years (95% CI: 10-30%). This pattern was consistently evident across subgroups defined by history of vascular disease, but was less evident for deaths from vascular disease.

CONCLUSIONS

Our results highlight the importance of maintaining a healthy lifestyle through to old age, regardless of history of vascular disease.

Surgical management of lung cancer in Western Australia in 1996 and its outcomes

BACKGROUND

All cases of lung cancer diagnosed in Western Australia in 1996 in which surgery was the primary treatment, were reviewed. Reported herein are the characteristics of the patients, the treatment outcomes and a comparison of the management undertaken with that recommended by international guidelines.

METHODS

All patients with a new diagnosis of lung cancer in Western Australia in the calendar year of 1996 were identified using two different population-based registration systems: the Western Australian (WA) Cancer Registry and the WA Hospital Morbidity Data System. A structured questionnaire on the diagnosis and management was completed for each case. Date of death was determined through the WA Cancer Registry.

RESULTS

Six hundred and sixty-eight patients with lung cancer were identified; 132 (20%) were treated with surgery. Lobectomy was the most frequently performed procedure (71%), followed by pneumonectomy (19%). Major complications affected 23% of patients. Postoperative mortality was 6% (3% lobectomy, 12% pneumonectomy). At 5 years the absolute survival was as follows for stage I, II, IIIA, IIIB, respectively: 51%, 45%, 12%, 5%.

CONCLUSIONS

Investigations and choice of surgery in WA in 1996 reflect current international guidelines. The survival of patients with resectable lung cancer remains unsatisfactory.

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.

Mortality and recurrent cardiac events after coronary artery bypass graft: long term outcomes in a population study

OBJECTIVE

To determine 30 day mortality, long term survival, and recurrent cardiac events after coronary artery bypass graft (CABG) in a population.

DESIGN

Follow up study of patients prospectively entered on to a cardiothoracic surgical database. Record linkages were used to obtain data on readmissions and deaths.

PATIENTS

8910 patients undergoing isolated first CABG between 1980 and 1993 in Western Australia.

MAIN OUTCOME MEASURES

30 day and long term survival, readmission for cardiac event (acute myocardial infarction, unstable angina, percutaneous transluminal coronary angioplasty or reoperative CABG).

RESULTS

There were 3072 deaths to mid 1999. 30 day and long term survival were significantly better in patients treated in the first five years than during the following decade. The age of the patients, proportion of female patients, and number of grafts increased over time. An urgent procedure (odds ratio 3.3), older age (9% per year) and female sex (odds ratio 1.5) were associated with increased risk for 30 day mortality, while age (7% per year) and a recent myocardial infarction (odds ratio 1.16) influenced long term survival. Internal mammary artery grafts were followed by better short and long term survival, though there was an obvious selection bias in favour of younger male patients.

CONCLUSIONS

This study shows worsening crude mortality at 30 days after CABG from the mid 1980s, associated with the inclusion of higher risk patients. Older age, an acute myocardial infarction in the year before surgery, and the use of sephenous vein grafts only were associated with poorer long term survival and greater risk of a recurrent cardiac event. Female sex predicted recurrent events but not long term survival.

Outcomes of out-of-hospital cardiac arrest patients in Perth, Western Australia, 1996-1999

STUDY OBJECTIVE

To describe the epidemiology and survival from out-of-hospital cardiac arrest.

DESIGN

Longitudinal follow-up study from the time of paramedic attendance to 12 months later.

SETTING

Perth, Western Australia (WA), a metropolitan capital city with an adult population of approximately one million people.

METHOD

The St John Ambulance Australia (WA Ambulance Service Incorporated) cardiac arrest database was linked to the WA hospital morbidity and mortality data using probabilistic matching.

INCIDENCE

Of 3730 cardiorespiratory arrests in 1996-1999, the age standardised rate of arrests of presumed cardiac origin, where resuscitation was attempted (n=1293) was 32.9 per 100000 person-years and 7.1 per 100000 person-years for bystander-witnessed VF/VT arrests.

SURVIVAL

Survival to 28 days was 6.8% following all bystander-witnessed cardiac arrests; 10.6% following bystander-witnessed VF/VT arrests and 33% for paramedic-witnessed cardiac arrests. Logistic regression analysis showed an inverse association between ambulance response time interval and survival following all bystander-witnessed cardiac arrests (and VF/VT arrests). ONE YEAR SURVIVAL: 89% of bystander-witnessed cardiac arrest survivors and 92% of paramedic-witnessed cardiac arrests were still alive at 1 year post-arrest.

CONCLUSION

The trends in occurrence and survival following out-of-hospital cardiac arrest in Perth, WA, are similar to those found elsewhere. There is an opportunity to strengthen the chain of survival by reducing the response time interval and increasing the use of bystander cardiopulmonary resuscitation (CPR). First-responder programs and public access defibrillation will need to be considered in the light of local demographics, location and the epidemiologic features of out-of-hospital cardiac arrest.