Incorporating competing risk theory into evaluations of changes in cancer survival: making the most of cause of death and routinely linked sociodemographic data.

BACKGROUND: Relative survival is the most common method used for measuring survival from population-based registries. However, the relative survival concept of 'survival as far as the cancer is concerned' can be biased due to differing non-cancer risk of death in the population with cancer (competing risks). Furthermore, while relative survival can be stratified or standardised, for example by sex or age, adjustment for a broad range of sociodemographic variables potentially influencing survival is not possible. In this paper we propose Fine and Gray competing risks multivariable regression as a method that can assess the probability of death from cancer, incorporating competing risks and adjusting for sociodemographic confounders. METHODS: We used whole of population, person-level routinely linked Western Australian cancer registry and mortality data for individuals diagnosed from 1983 to 2011 for major cancer types combined, female breast, colorectal, prostate, lung and pancreatic cancers, and grade IV glioma. The probability of death from the index cancer (cancer death) was evaluated using Fine and Gray competing risks regression, adjusting for age, sex, Indigenous status, socio-economic status, accessibility to services, time sub-period and (for all cancers combined) cancer type. RESULTS: When comparing diagnoses in 2008-2011 to 1983-1987, we observed substantial decreases in the rate of cancer death for major cancer types combined (N = 192,641, - 31%), female breast (- 37%), prostate (- 76%) and colorectal cancers (- 37%). In contrast, improvements in pancreatic (- 15%) and lung cancers (- 9%), and grade IV glioma (- 24%) were less and the cumulative probability of cancer death for these cancer types remained high. CONCLUSION: Considering the justifiable expectation for confounder adjustment in observational epidemiological studies, standard methods for tracking population-level changes in cancer survival are simplistic. This study demonstrates how competing risks and sociodemographic covariates can be incorporated using readily available software. While cancer has been focused on here, this technique has potential utility in survival analysis for other disease states.

The association between general practitioner regularity of care and 'high use' hospitalisation.

BACKGROUND: In Australia, as in many high income countries, there has been a movement to improve out-of-hospital care. If primary care improvements can yield appropriately lower hospital use, this would improve productive efficiency. This is especially important among 'high cost users', a small group of patients accounting for disproportionately high hospitalisation costs. This study aimed to assess the association between regularity of general practitioner (GP) care and 'high use' hospitalisation. METHODS: This retrospective, cohort study used linked administrative and survey data from the 45 and Up Study, conducted in New South Wales, Australia. The exposure was regularity of GP care between 1 July 2005 and 30 June 2009, categorised by quintile (lowest to highest). Outcomes were 'high use' of hospitalisation (defined as ≥3 and ≥ 5 admissions within 12 months), extended length of stay (LOS, ≥30 days), a combined metric (≥3 hospitalisations in a 12 month period where ≥1 hospitalisation was ≥30 days) and 30-day readmission between 1 July 2009 and 31 December 2017. Associations were assessed using multivariable logistic regression. Potential for outcome prevention in a hypothetical scenario where all individuals attain the highest GP regularity was estimated via the population attributable fraction (PAF). RESULTS: Of 253,500 eligible participants, 15% had ≥3 and 7% had ≥5 hospitalisations in a 12-month period. Five percent of the cohort had a hospitalisation lasting ≥30 days and 25% had a readmission within 30 days. Compared with lowest regularity, highest regularity was associated with between 6% (p < 0.001) and 11% (p = 0.027) lower odds of 'high use'. There was a 7-8% reduction in odds for all regularity levels above 'low' regularity for LOS ≥30 days. Otherwise, there was no clear sequential reduction in 'high use' with increasing regularity. The PAF associated with a move to highest regularity ranged from 0.05 to 0.13. The number of individuals who could have had an outcome prevented was estimated to be between 269 and 2784, depending on outcome. CONCLUSIONS: High GP regularity is associated with a decreased likelihood of 'high use' hospitalisation, though for most outcomes there was not an apparent linear association with regularity.

Regularity of contact with GPs: Measurement approaches to improve valid associations with hospitalization.

BACKGROUND: Studies examine longitudinal continuity of GP contact though few consider 'regularity of GP contact', i.e., the dispersion of contacts over time. Increased regularity may indicate planned ongoing care. Current measures of regularity may be correlated with the number of contacts and may not isolate the phenomenon of interest. OBJECTIVES: To compare two published and one newly developed regularity index in terms of their ability to measure regularity of GP contacts independently of the number of contacts and the impact on their association with hospitalization. METHODS: A cohort at risk of diabetes-related hospitalization in Western Australia from 1990 to 2004 was identified using linked administrative data. For each regularity index, relationships with number of GP contacts were assessed. Hospitalization was then regressed on each index with and without number of contacts as a covariate. RESULTS: Among 153,414 patients the new regularity index showed a reduced association with number of contacts compared with existing indices. Associations with hospitalization differed between measures; for previously published indices, there were no significant associations between regularity and hospitalization, whereas on the new index, most regular GP contact was associated with reduced hospitalization (IRR = 0.90, 95% CI = 0.88-0.93). When number of contacts was added as a covariate, point estimates for this index showed little change, whereas for existing measures this addition changed point estimates. CONCLUSION: A new measure of regularity of GP contact was less correlated with the number of contacts than previously published measures and better suited to estimating unconfounded relationships of regularity with hospitalization.

Cohort study of Western Australia computed tomography utilisation patterns and their policy implications.

BACKGROUND: Computed tomography (CT) scanning is a relatively high radiation dose diagnostic imaging modality with increasing concerns about radiation exposure burden at the population level in scientific literature. This study examined the epidemiology of adult CT utilisation in Western Australia (WA) in both the public hospital and private practice settings, and the policy implications. METHODS: Retrospective cohort design using aggregate adult CT data from WA public hospitals and Medical Benefits Schedule (MBS) (mid-2006 to mid-2012). CT scanning trends by sex, age, provider setting and anatomical areas were explored using crude CT scanning rates, age-standardised CT scanning rates and Poisson regression modelling. RESULTS: From mid-2006 to mid-2012 the WA adult CT scanning rate was 129 scans per 1,000 person-years (PY). Females were consistently scanned at a higher rate than males. Patients over 65 years presented the highest scanning rates (over 300 scans per 1,000 PY). Private practice accounted for 73% of adult CT scans, comprising the majority in every anatomical area. In the private setting females predominately held higher age-standardised CT scanning rates than males. This trend reversed in the public hospital setting. Patients over 85 years in the public hospital setting were the most likely age group CT scanned in nine of ten anatomical areas. Patients in the private practice setting aged 85+ years were relatively less prominent across every anatomical area, and the least likely age group scanned in facial bones and multiple areas CT scans. CONCLUSION: In comparison to the public hospital setting, the MBS subsidised private sector tended to service females and relatively younger patients with a more diverse range of anatomical areas, constituting the majority of CT scans performed in WA. Patient risk and subsequent burden is greater for females, lower ages and some anatomical areas. In the context of a national health system, Australia has various avenues to monitor radiation exposure levels, improve physician training and modify funding mechanisms to ensure individual and population medical radiation exposure is as low as reasonably achievable.

Cohort profile: understanding health service system needs for people with intellectual disability using linked data in New South Wales, Australia.

This cohort profile describes one of the largest linked datasets in the world concerning the health of people with intellectual disability. The cohort comprises a retrospective group of 100,089 individuals with intellectual disability who received disability and/or health services in New South Wales, Australia. Of these participants, 34% were female, with a median age at cohort entry of 3 years (interquartile range, 0-19). A separate comparator cohort included 455,677 individuals, matched by 5-year age group, sex, and residential postcode at a 5:1 ratio. Initial results indicate that between 2001 and 2018, people with intellectual disability experienced more than double the rate of hospitalisations (538 vs. 235 per 1,000 person-years), as well as markedly higher rates of emergency department presentations (707 vs. 379 per 1,000 person-years) and use of ambulatory mental health services (1,012 vs. 157 per 1,000 person-years), relative to the comparator cohort. The largest disparities in hospital admissions were for mental disorders, dialysis, and diseases of the nervous system and sense organs. Furthermore, individuals with intellectual disability had more than double the rate of dispensed medications found in the comparator cohort. Of these medications, 46.6% were for the treatment of nervous system conditions, as opposed to 24.7% for the comparator cohort. The mean±standard deviation age at death was 52±19 years for people with intellectual disability and 64±22 years for the comparator participants.

Pelvic organ prolapse surgery in Western Australia: a population-based analysis of trends and peri-operative complications.

INTRODUCTION AND HYPOTHESIS: We previously described a declining rate of surgery in the treatment of pelvic organ prolapse (POP) in Western Australia. This paper builds on previous work by examining temporal trends and the post-operative risk of in-hospital complications, following first time incident prolapse surgery in a population-based cohort of women. METHODS: We investigated rates of prolapse surgery between 1988 and 2005 according to age group and concomitant procedure type for 34,509 women whose data were extracted from the WA Data Linkage System. We investigated changes over time in the demographic characteristics of women undergoing surgery and whether the presence of selected concomitant procedures increased the risk of in-hospital complications. RESULTS: During the study period, 34,509 women underwent an incident surgery for POP. Concomitant hysterectomy was performed in more than half of all surgeries (52.4 %) and a concomitant urinary incontinence (UI) surgery was noted in 25.8 %. 10.9 % of patients experienced a complication of interest, with the highest percentage of complications recorded in women who underwent multi-concomitant surgery. After controlling for age, comorbidity and time period we found that concomitant UI surgery increases in-hospital complications (OR 1.61 95 % CI 1.42-1.83) only in women who have a repair procedure (colporrhaphy and/or enterocele repair). There was no significant effect of concomitant procedures in women who underwent a combined repair and apical prolapse procedure. CONCLUSIONS: Surgery to treat prolapse is common, has low mortality and concomitant surgery only increases complications when combined with simpler prolapse surgery.

Effect of private insurance incentive policy reforms on trends in coronary revascularisation procedures in the private and public health sectors in Western Australia: a cohort study.

BACKGROUND: The Australian federal government introduced private health insurance incentive policy reforms in 2000 that increased the uptake of private health insurance in Australia. There is currently a lack of evidence on the effect of the policy reforms on access to cardiovascular interventions in public and private hospitals in Australia. The aim was to investigate whether the increased private health insurance uptake influenced trends in emergency and elective coronary artery revascularisation procedures (CARPs) for private and public patients. METHODS: We included 34,423 incident CARPs from Western Australia during 1995-2008 in this study. Rates of emergency and elective CARPs were stratified for publicly and privately funded patients. The average annual percent change (AAPC) in trend was calculated before and after 2000 using joinpoint regression. RESULTS: The rate of emergency CARPs, which were predominantly percutaneous coronary interventions (PCIs) with stenting, increased throughout the study period for both public and private patients (AAPC=12.9%, 95% CI=5.0,22.0 and 14.1%, 95% CI=9.8,18.6, respectively) with no significant difference in trends before and after policy implementation. The rate of elective PCIs with stenting from 2000 onwards remained relatively stable for public patients (AAPC=-6.0, 95% C= -16.9,6.4), but increased by 4.1% on average annually (95% CI=1.8,6.3) for private patients (pdifference=0.04 between groups). This rate increase for private patients was only seen in people aged over 65 years and people residing in high socioeconomic areas. CONCLUSIONS: The private health insurance incentive policy reforms are a likely contributing factor in the shift in 2000 from public to privately-funded elective PCIs with stenting. These reforms as well as the increasing number of private hospitals may have been successful in increasing the availability of publicly-funded beds since 2000.

Radiation dosimetry assessment of routine CT scanning protocols used in Western Australia.

Technical data on local CT practice in Western Australia were collected for five major CT providers using a self-completed questionnaire. The CTDIvol DLP and effective dose for each protocol were obtained and providers were ranked according to radiation burden for each clinical scenario. The mean, median, 75th percentile and standard deviation were calculated for both effective dose and DLP for each scenario and these values were compared with published data. CT utilisation data were used to estimate the attributable radiation dose to the WA population and the potential change in population annual effective dose according to the protocol used was estimated. We found that wide variations in technique and radiation dose exist across providers for similar examinations, producing a higher radiation burden than reported internationally. As expected, the CT protocol used dramatically affects the radiation dose received, and this has a significant effect on annual population dose. This study highlights the need for recognition and understanding of both the degree of variation in radiation dose across providers and the relatively high radiation burden afforded by protocols in use in Western Australia so that necessary dialogue can be launched for practitioner consensus on appropriate diagnostic reference levels in CT scanning.

Enhanced primary care improves GP service regularity in older patients without impacting on service frequency.

The objective ofthis study was to assess the impact of Enhanced Primary Care service utilisation on subsequent GP service regularity and frequency. The study involved a retrospective population-based longitudinal cohort using linked administrative health records of hospital and primary care services for people over the age of 65 years. Multinomial logistic regression modelling was used to evaluate changes in the relative likelihood of increased primary care service regularity and frequency in exposed and unexposed individuals adjusting for age, sex and recent chronic disease hospitalisation history. Enhanced Primary Care services significantly and substantially increased the relative likelihood of increased regularity with no corresponding higher likelihood of increased frequency of GP contact. Increased regularity was more likely with increasing age except for the oldest age group (90+ years). Some chronic disease histories (e.g. diabetes) showed a higher likelihood of improved regularity while others were less likely to produce an increased regularity (e.g. hypertension). The study suggests a capacity for modification of physician and patient behaviour using incentivised services within the current fee-for-service system in Australia.

A post-radical-prostatectomy nomogram incorporating new pathological variables and interaction terms for improved prognosis.

OBJECTIVE: To evaluate new variables in prostate pathology reporting including, the per cent of Gleason patterns 4 and/or 5 (% 4/5), presence or absence of intraductal carcinoma of the prostate (IDCP), tumour volume and the prostatic zone of tumour origin as predictors of post-radical-prostatectomy (RP) biochemical recurrence (BCR). To develop an optimal postoperative nomogram for patients with prostate cancer. PATIENTS AND METHODS: Our study cohort was 1939 eligible patients from the Abbott West Australian Prostatectomy Database. Multivariate Cox proportional hazard regression models were developed to predict BCR which was defined as prostate-specific antigen (PSA) ≥ 0.2 ng/mL. Our models and the 2009 Kattan postoperative nomogram were compared in terms of discrimination and calibration, with internal validation of our final model performed using bootstrapping methods. Our final model is presented as a nomogram. RESULTS: The Kattan nomogram was accurate in discriminating our patients according to risk (concordance index: 0.791) but calibration analysis indicated underestimation of patient risk, particularly for high-risk disease. Our nomogram incorporates % 4/5, IDCP and prostate weight plus interaction terms between % 4/5, positive surgical margins and extracapsular extension, giving improved predictive accuracy (concordance index: 0.828) and calibration. CONCLUSIONS: Nomograms that predict risk of BCR defined as PSA ≥ 0.4 ng/mL may not be optimal for patient cohorts where BCR is defined as PSA ≥ 0.2 ng/mL. If our findings are validated in other populations, current post-RP nomograms may be improved to a modest degree by incorporating the new variables prostate weight, IDCP and % 4/5, and by considering interactions between predictive variables.

Effects of the Medicare enhanced primary care program on primary care physician contact in the population of older Western Australians with chronic diseases.

OBJECTIVE: Assess uptake of Medicare's enhanced primary care (EPC) services in Western Australia (WA) in 2001 to 2006, evaluating effect of EPC services on the regularity of contact with general practitioners (GPs) in patients aged 65+ years. METHOD: Whole-population cohort study using linked routinely collected health service data from State and Federal health databases. Analyses include age-standardised rate of EPC services, odds of EPC utilisation relative to other GP services using logistic regression, and total GP service regularity pre- and post-implementation of the EPC program. RESULTS: EPC services provided to WA seniors increased 345% 2001 to 2006, comprising an increasing proportion of the total GP services (1.1 to 3.6%). Uptake of EPC services accelerated abruptly after 2004 due to greater use of 'care plans'. EPC services were associated with a history of chronic disease, especially type 2 diabetes (OR=1.74, 95% CI 1.66-1.82). Regularity of total GP services was improved with any EPC service exposure, with greater improvement occurring in the presence of annual EPC service exposure. CONCLUSIONS: EPC item uptake responded favourably to item changes from Medicare Australia. Prior exposure to EPC items increased the regularity of GP services, an outcome inversely associated with chronic disease progression.

Long-term health risks for children and young adults after infective gastroenteritis.

To quantify the risk and types of sequelae attributable to prior enteric infections, we undertook a population-based retrospective cohort study using linked administrative records. The risk for first-time hospitalization for sequelae was modeled by using Cox proportional regression analysis controlling for other health and sociodemographic factors. We identified a significant increase of 64% in the rate of first-time hospitalization for sequelae for persons with prior enteric infections: 52% for intragastrointestinal sequelae and 63% for extragastrointestinal sequelae compared with first-time hospitalization for those without prior infection. Extragastrointestinal sequelae occurred predominantly during the first 5 years after first-time enteric infection. In contrast, most intragastrointestinal sequelae occurred >10 years later. Infective gastroenteritis during childhood or adolescence increases the risk for first-time hospitalization for intragastrointestinal and extragastrointestinal disease over the 2 decades after first-time enteric infection, highlighting the importance of identifying ways of reducing the incidence of such infections.

Does minimum follow-up time post-diagnosis matter? An assessment of changing loss of life expectancy for people with cancer in Western Australia from 1982 to 2016.

BACKGROUND: Cancer survival has improved in Western Australia (WA) over recent decades. Loss of life expectancy (LOLE) is a useful measure for assessing cancer survival at a population-level. Some previous studies estimating LOLE have required a minimum follow-up beyond diagnosis to reduce the impact of modelled extrapolation, while others have not. The first aim of this study was to assess the impact of minimum length of follow-up on LOLE estimates for people diagnosed in 2006 with female breast, colorectal, prostate, lung, cervical, combined oesophageal and stomach cancers, and melanoma. Based on these results, the second aim was to assess temporal changes in LOLE for these cancer types for diagnoses between 1982 and 2016. METHODS: Person-level linked cancer registry and mortality data were used for invasive primary cancer diagnoses for WA residents aged 15-89 years. The analysis for aim one included cases diagnosed from 1982 to the end of 2006, followed to the end of 2006 (i.e. no minimum follow-up), 2011 (i.e. five years minimum follow-up, assuming survival) or 2016 (i.e. 10 years minimum follow-up). To achieve the second study aim, the diagnostic period was extended to the end of 2016. Life expectancy estimates were obtained after fitting flexible parametric relative survival models. Single-year age and sex-specific death rates were used as a reference to estimate LOLE and proportionate loss of life expectancy. RESULTS: Temporal changes were not reported for prostate, cervical, oesophageal and stomach cancers or melanoma, due to differences in LOLE estimates by minimum follow-up time, or estimate imprecision. Marked reductions in LOLE were observed for female breast and colorectal cancer. There was minimal absolute reduction for lung cancer, where LOLE remained high. CONCLUSION: This study considered the appropriateness of including recent cancer diagnoses when assessing temporal changes in LOLE, finding variation in estimates with differing minimum follow-up or high parameter uncertainty for most included cancer types. Temporal changes in LOLE in-turn reflected changes in the life expectancy of the general population, cancer detection and management. These factors must be considered when estimating and interpreting LOLE estimates.

Association between continuity of provider-adjusted regularity of general practitioner contact and unplanned diabetes-related hospitalisation: a data linkage study in New South Wales, Australia, using the 45 and Up Study cohort.

OBJECTIVE: To assess the association between continuity of provider-adjusted regularity of general practitioner (GP) contact and unplanned diabetes-related hospitalisation or emergency department (ED) presentation. DESIGN: Cross-sectional study. SETTING: Individual-level linked self-report and administrative health service data from New South Wales, Australia. PARTICIPANTS: 27 409 survey respondents aged ≥45 years with a prior history of diabetes and at least three GP contacts between 1 July 2009 and 30 June 2015. MAIN OUTCOME MEASURES: Unplanned diabetes-related hospitalisations or ED presentations, associated costs and bed days. RESULTS: Twenty-one per cent of respondents had an unplanned diabetes-related hospitalisation or ED presentation. Increasing regularity of GP contact was associated with a lower probability of hospitalisation or ED presentation (19.9% for highest quintile, 23.5% for the lowest quintile). Conditional on having an event, there was a small decrease in the number of hospitalisations or ED presentations for the low (-6%) and moderate regularity quintiles (-8%), a reduction in bed days (ranging from -30 to -44%) and a reduction in average cost of between -23% and -41%, all relative to the lowest quintile. When probability of diabetes-related hospitalisation or ED presentation was included, only the inverse association with cost remained significant (mean of $A3798 to $A6350 less per individual, compared with the lowest regularity quintile). Importantly, continuity of provider did not significantly modify the effect of GP regularity for any outcome. CONCLUSIONS: Higher regularity of GP contact-that is more evenly dispersed, not necessarily more frequent care-has the potential to reduce secondary healthcare costs and, conditional on having an event, the time spent in hospital, irrespective of continuity of provider. These findings argue for the advocacy of regular care, as distinct from solely continuity of provider, when designing policy and financial incentives for GP-led primary care.

Central zone carcinoma of the prostate gland: a distinct tumor type with poor prognostic features.

PURPOSE: The central zone of the prostate gland is a region rarely associated with carcinoma. To our knowledge central zone tumors have not previously been compared to carcinoma originating in the peripheral or transition zone of the prostate gland. MATERIALS AND METHODS: All 2,010 radical prostatectomy cases seen at our institution from October 1998 to December 2006 were reviewed to identify tumor zonal origin. Central zone carcinoma was characterized and compared with tumors of other zones. RESULTS: Zonal origin was determined in a total of 2,494 tumors in 1,703 cases. Of the tumors 63 (2.5%) were of central zone origin with 59 of the 63 representing the index or main tumor. Comparative analysis of a defined subset of 726 cases showed that central zone cancers were significantly more aggressive than peripheral or transition zone cancers with a far greater risk of extracapsular extension, seminal vesicle invasion and positive surgical margins. Escape from the gland was often via the ejaculatory ducts and seminal vesicles. Kaplan-Meier analysis confirmed that the probability of post-prostatectomy biochemical failure was double that of tumors of the other zones with a far more rapid rate of failure. Multivariate Cox regression analysis identified Gleason grade, positive margins, extracapsular extension, tumor volume and preoperative serum prostate specific antigen as the major contributors to this poor prognosis, rather than specific zonal origin. CONCLUSIONS: To our knowledge this study provides the first characterization and comparative analysis of central zone carcinoma, identifying these tumors as a rare but highly aggressive form of prostate carcinoma with a distinct route of spread from the gland that contrasts with tumors of other zones. Preoperative identification is currently hampered by the avoidance of biopsy targeting the central zone. However, if recognized preoperatively, aggressive intervention may possibly improve the currently bleak outlook.

The epidemiology and cost of falls requiring hospitalisation in children in Western Australia: a study using linked administrative data.

OBJECTIVE: The aim of this study was to examine the epidemiology and health system cost of children's falls resulting in hospitalisation in 2003 in Western Australia. METHODS: The Injury Cost Database was used to identify children who were admitted to hospital with a falls related injury. Adjusted incidence rate ratios (IRR) of hospitalisation were modelled using Poisson regression. In-patient hospital costs were assigned using the published DRG costs for Western Australia. These costs were then extrapolated to health system costs based on previously published relative proportions. RESULTS: When adjusted for other covariates in the model males had a 53% higher incidence of falls requiring hospitalisation compared with females. Aboriginal children had a 36% higher incidence compared with their non-Aboriginal counterparts, and the incidence of falls reduced with increasing age. The total cost of in-patient hospitalisation associated with children's falls in Western Australia was A$4,554,000 with an average cost of A$1876 per case. In children aged 0-4 years and 10-14 years the highest cost resulted from falls on the flat (slips and trips). However, in children aged 5-9 years injuries resulting from falls from playground equipment resulted in both the highest cost group (A$539,000) and the highest cost per case (A$1917). The total cost to the health system of children's falls in Western Australia in 2003 were estimated to be A$21.5 million, with the total cost to the community estimated at A$108.5 million. CONCLUSION: Children's falls impose a considerable burden and cost to both the health care system and the community. This study has provided information on where the burden of risk and the majority of costs lie, namely males, Aboriginal children and for children aged 5-9 years, unlike their younger and older peers, playground equipment.

Earlier Initiation of Community-Based Palliative Care Is Associated With Fewer Unplanned Hospitalizations and Emergency Department Presentations in the Final Months of Life: A Population-Based Study Among Cancer Decedents.

CONTEXT: Although community-based palliative care (CPC) is associated with decreased acute care use in the lead up to death, it is unclear how the timing of CPC initiation affects this association. OBJECTIVES: We aimed to explore the association between timing of CPC initiation and hospital use, over the final one, three, six, and 12 months of life. METHODS: We conducted a retrospective, population-based study in Perth, Western Australia. Linked administrative data including cancer registry, mortality, hospital admissions, emergency department (ED), and CPC records were obtained for cancer decedents from 1 January, 2001 to 31 December, 2011. The exposure was month of CPC initiation; outcomes were unplanned hospitalizations, ED presentations, and associated costs. RESULTS: Of 28,331 decedents residing in the CPC catchment area, 16,439 (58%) accessed CPC, mostly (64%) in the last three months of life. Initiation of CPC before the last six months of life was associated with a lower mean rate of unplanned hospitalizations in the last six months of life (1.4 vs. 1.7 for initiation within six months of death); associated costs were also lower ($(A2012) 12,976 vs. $13,959, comparing the same groups). However, those initiating CPC earlier did show a trend toward longer time in hospital when admitted, compared to those initiating in the final month of life. CONCLUSIONS: When viewed at a population level, these results argue against temporally restricting access to CPC, as earlier initiation may pay dividends in the final few months of life in terms of fewer unplanned hospitalizations and ED presentations.

The importance of historical residential address information in longitudinal studies using administrative health data.

Background: When information on changes in address or migration of people to or from a study jurisdiction is unavailable in longitudinal studies, issues relating to loss-to-follow-up and misclassification bias may result. This study investigated how estimations of associations between general practitioner (GP) contact and hospital use were affected by incomplete address and migration data. Methods: This was a retrospective population-based cohort study of Western Australians from 1990 to 2004. Linked administrative data including mortality records, hospital admissions, primary care and Electoral Roll records were used. Regularity of GP contact, based on the variance of the number of days between GP visits, was calculated for each person-year. Outcomes were the number and costs (A$2014) of diabetes-related hospital admissions in the following year. Models were estimated separately for cohorts where (i) postcode was ascertained at study commencement and held constant, and (ii) postcode and residency within Western Australia were updated with each change of address recorded on the Electoral Roll over the study period. Results: Updating address data reduced total person-years by 11% and changed the distribution of covariates. Estimations of associations between patterns of GP contact and number of hospitalizations changed; the incidence rate ratios measuring the relationship with the most regular GP contact (baseline of those with <2 GP visits) changed from 0.81 [95% confidence interval (CI) 0.66-1.00] to 0.42 (95% CI 0.33-0.53) after updating postcode information. Impacts on cost models were smaller, though still statistically significant. Conclusions: Longitudinal studies using administrative data may report biased results if they ignore address changes and migration. Researchers should attempt to link to these data wherever possible, or choose study designs which these issues are less likely to affect. Custodians should be aware that such data can be vital to high quality research.

Pre-clinical evaluation of 2,3-dimercaptosuccinic acid as a radiation nephrotoxicity protective agent during radiopeptide therapy of neuroendocrine malignancy.

AIM: To determine if dimercaptosuccinic acid (DMSA), an agent originally developed as a safe non-toxic antidote for heavy metal poisoning, would be useful as a kidney radiation dose reduction agent in patients undergoing radiopeptide therapy for cancer. METHODS: Thirty-six adult male Wistar rats were injected via the penile vein with 10 MBq of 177Lu-DOTA-tyr(3)-octreotate. At 30 min after the radiopeptide injection, 18 of the animals (intervention group) were injected with 0.15 mg x g(-1) of DMSA (i.p.). Samples were collected for gamma counting at 24 (n=12), 48 (n=12) and 72 h (n=12) after administration of the radiopeptide. At each time point, the percentage injected dose per gram of tissue in each sample of the six control animals was compared with that of the six animals from the DMSA injection regimen. RESULTS: The i.p. injection of 0.15 mg x g(-1) of DMSA 30 min following the administration of the 177Lu-DOTATATE reduced the mean (95% CI) kidney retention of radiopeptide by 15.6% (2.6-24.6) at 72 h while not significantly affecting uptake in other organs. Statistical testing of the difference between the two groups of animals (DMSA versus controls) at 72 h post-administration of the radiopeptide indicated only a 3% chance that the magnitude of the reduction in kidney radiopeptide retention observed would be expected due to natural variation (i.e., if there was no difference between the groups). CONCLUSION: This study has indicated that DMSA has the potential to selectively reduce radiopeptide kidney retention. Further work is necessary to determine the most effective dose of DMSA and the most effective timing regimen, and to examine the clinical efficacy of several other chelating agents.

Use of Western Australian linked hospital morbidity and mortality data to explore theories of compression, expansion and dynamic equilibrium.

Three hypotheses have been advanced to predict changes in population health in countries experiencing low birth and death rates, and increasing expectation of life. Determining which of these best accounts for changing patterns of illness and death is an important step in understanding both the public health and economic impacts of health interventions in an ageing population. The aim of this study was to use the WA Data Linkage System to evaluate the compression, expansion and dynamic equilibrium theories in Western Australia. Changes in life expectancy, average age at first-time hospitalisation and time spent in chronic disabling or activity limiting states were used to evaluate the competing hypotheses. Life expectancy increased by 4.0 and 2.6 years over the 24-year study period in males and females, respectively. However, average time spent with a diagnosed chronic disabling condition increased by 9.2 and 9.4 years in males and females, respectively. These results suggest that an increase in the "medicalisation of more serious morbidity" may be in operation in Australia.