Association between antihypertensive medicine use and risk of ovarian cancer in women aged 50 years and older

BACKGROUND

Epithelial ovarian cancer (EOC) has few modifiable risk factors. There is evidence that some antihypertensive medicines may have cancer preventive and/or therapeutic actions; therefore, we assessed the associations between use of different antihypertensive medicines and risk of specific EOC histotypes.

METHODS

Our nested case-control study of linked administrative health data included 6070 Australian women aged over 50 years diagnosed with EOC from 2004 to 2013, and 30,337 matched controls. We used multivariable conditional logistic regression to estimate odds ratios (ORs) and 95 % confidence intervals (CIs) for the association between ever use of each antihypertensive medicine group, including beta-adrenergic blockers, angiotensin converting enzyme inhibitors, angiotensin II receptor blockers, calcium channel blockers, diuretics, and alpha blockers, and the risk of EOC overall and separately for the serous, endometrioid, mucinous, clear cell and other histotypes.

RESULTS

We found that most antihypertensive medicines were not associated with risk of EOC. However, women who used calcium channel blockers had a reduced risk of serous EOC (OR= 0.89, 95 % CI:0.81,0.98) and use of combination thiazide and potassium-sparing diuretics was associated with an increased risk of endometroid EOC (OR= 2.09, 95 % CI:1.15,3.82).

CONCLUSION

Our results provide little support for a chemo-preventive role for most antihypertensives, however, the histotype-specific associations we found warrant further investigation.

Perioperative Beta-Blocker Supply and Survival in Women With Epithelial Ovarian Cancer and a History of Cardiovascular Conditions

PURPOSE

Surgery for epithelial ovarian cancer (EOC) may activate stress-inflammatory responses that stimulate tumor growth and increase metastatic growth. Animal and in vitro studies have shown that inhibition of the catecholamine-induced inflammatory response via beta-adrenergic receptor blockade has antitumor potential in EOC. However, observational studies have reported mixed results. We assessed whether beta-blocker (BB) use at the time of primary ovarian cancer surgery was associated with improved survival in a large population-based study.

MATERIALS AND METHODS

Using linked administrative data, a population-based cohort of 3,844 Australian women age 50 years or older with a history of cardiovascular conditions who underwent surgery for EOC was followed for survival outcomes. The average treatment effect of selective BB (SBB) and nonselective BB (NSBB) supply at the time of surgery on survival was estimated from a causal inference perspective using covariate-balanced inverse probability of treatment weights with flexible parametric survival models that allowed for time-varying survival effects.

RESULTS

Around the time of surgery, 560 (14.5%) women were supplied a SBB and 67 (1.7%) were supplied a NSBB. At 2 years postsurgery, the survival proportion was 80% (95% CI, 68 to 88) for women dispensed NSBBs at surgery compared with 69% (95% CI, 67 to 70) for women not supplied NSBBs. The survival advantage appeared to extend to at least 8 years postsurgery. No association was observed for women dispensed a SBB around the time of surgery.

CONCLUSION

Perioperative supply of NSBBs appeared to confer a survival advantage for women age over 50 years with a history of cardiovascular conditions. Long-term clinical trials are required to confirm these findings.

Nitrogen-Based Bisphosphonate Use and Ovarian Cancer Risk in Women Aged 50 Years and Older

BACKGROUND

There are few readily modifiable risk factors for epithelial ovarian cancer; pre-clinical studies suggest bisphosphonates could have chemo-preventive actions. Our study aimed to assess the association between use of nitrogen-based bisphosphonate medicine and risk of epithelial ovarian cancer, overall and by histotype.

METHODS

We conducted a case-control study nested within a large linked administrative dataset including all Australian women enrolled for Medicare, Australia's universal health insurance scheme, between July 2002 and December 2013. We included all women with epithelial ovarian cancer diagnosed at age 50 years and older between 1st July 2004 and 31st December 2013 (n = 9,367) and randomly selected up to five controls per case, individually matched to cases by age, state of residence, area-level socioeconomic status, and remoteness of residence category (n = 46,830). We used prescription records to ascertain use of nitrogen-based bisphosphonates (ever use and duration of use), raloxifene and other osteoporosis medicines (non-nitrogen-based bisphosphonates, strontium and denosumab). We calculated adjusted odds ratios (OR) and 95% confidence intervals (CI) using conditional logistic regression.

RESULTS

Ever use of nitrogen-based bisphosphonates was associated with a reduced risk of epithelial ovarian cancer compared to non-use (OR = 0.81, 95%CI : 0.75-0.88). There was a reduced risk of both endometrioid (OR = 0.51, 95%CI : 0.33-0.79) and serous histotypes (OR = 0.84, 95%CI : 0.75-0.93), but no association with the mucinous or clear cell histotypes.

CONCLUSION

Use of nitrogen-based bisphosphonates was associated with a reduced risk of endometrioid and serous ovarian cancer. This suggests the potential for use for prevention, although validation of our findings is required.

794Bisphosphonate use and risk of ovarian cancer, a nested case-control study using national health data

Background

Epithelial ovarian cancer (EOC) is the eighth most common cancer in women, has a five-year survival of ∼45%, and very few established modifiable risk factors. Some evidence suggests that bisphosphonates could have chemopreventive benefits, but few epidemiological studies have investigated the association between bisphosphonate use and incidence of EOC.

Methods

We conducted a nested case-control study using linked administrative data. We identified 9,367 women over 50 years diagnosed with EOC (cases) from 2004 to 2013, and for each case identified five controls from the Australian Medicare Enrolment database matched by age, state, area of residence, and area-level socioeconomic disadvantage. We assessed the associations between bisphosphonate use using dispensed prescription data (ever use, duration and dose) and EOC (overall, by histotype), adjusting for comorbidities and MHT use. We conducted sensitivity analyses in women with complete ascertainment of dispensing claims and for residents of one Australian state that had linked with data linked to hospital procedures, including oophorectomy.

Results

Our analyses show an inverse association between bisphosphonate use and risk of EOC overall (OR = 0.81, 95%CI:0.75-0.88), and for endometrioid (OR = 0.51, 95%CI:0.33-0.79) and serous (OR = 0.84, 95%CI:0.75-0.93) histotypes. There was some evidence that higher dose and duration were associated with a greater reduction in risk. Results from sensitivity analyses were not appreciably different.

Conclusions

Bisphosphonate use was associated with lower risk of EOC, suggesting bisphosphonates may reduce risk of ovarian cancer development.

Key messages

Bisphosphonates may protect against development of serous and endometrioid ovarian cancers.

The role of renal mass biopsy in the management of small renal masses – patterns of use and surgeon opinion

Aims:

Renal mass biopsy (RMB) is advocated to improve management of small renal masses, however there is concern about its clinical utility. This study aimed to elicit opinions about the role of RMB in small renal mass management from surgeons managing renal cell carcinomas (RCC), and examine the frequency of pre-treatment biopsy in those with RCC.

Methods:

All surgeons in two Australian states (Queensland: n = 59 and Victoria: n = 108) who performed nephrectomies for RCC in 2012/2013 were sent questionnaires to ascertain views about RMB. Response rates were 54% for Queensland surgeons and 38% for Victorian surgeons. We used medical records data from RCC patients to determine RMB frequency.

Results:

Most Queensland (81%) and Victorian (59%) surgeons indicated they rarely requested RMB; however 34% of Victorians reported often requesting RMB, compared with no Queensland surgeons. This was consistent with medical records data: 17.6% of Victorian patients with T1a tumours received RMB versus 6.7% of Queensland patients ( p < 0.001). Surgeons’ principal concerns regarding RMB related to sampling reliability (90%) and/or histopathological interpretation (76%).

Conclusions:

Most surgeons report infrequent use of RMB for small renal masses, however we observed practice variation. The principal reasons for infrequent use were concerns about sampling reliability and histopathological interpretation, which may be valid in regions with less access to interventional radiologists and uropathologists. Further evidence is required to define patient groups for whom biopsy results will alter management.

Level of evidence:

Not applicable for this multicentre audit.

A Simple Clinical Tool for Stratifying Risk of Clinically Significant CKD after Nephrectomy: Development and Multinational Validation

BACKGROUND

Clinically significant CKD following surgery for kidney cancer is associated with increased morbidity and mortality, but identifying patients at increased CKD risk remains difficult. Simple methods to stratify risk of clinically significant CKD after nephrectomy are needed.

METHODS

To develop a tool for stratifying patients' risk of CKD arising after surgery for kidney cancer, we tested models in a population-based cohort of 699 patients with kidney cancer in Queensland, Australia (2012-2013). We validated these models in a population-based cohort of 423 patients from Victoria, Australia, and in patient cohorts from single centers in Queensland, Scotland, and England. Eligible patients had two functioning kidneys and a preoperative eGFR ≥60 ml/min per 1.73 m². The main outcome was incident eGFR <45 ml/min per 1.73 m² at 12 months postnephrectomy. We used prespecified predictors-age ≥65 years old, diabetes mellitus, preoperative eGFR, and nephrectomy type (partial/radical)-to fit logistic regression models and grouped patients according to degree of risk of clinically significant CKD (negligible, low, moderate, or high risk).

RESULTS

Absolute risks of stage 3b or higher CKD were <2%, 3% to 14%, 21% to 26%, and 46% to 69% across the four strata of negligible, low, moderate, and high risk, respectively. The negative predictive value of the negligible risk category was 98.9% for clinically significant CKD. The c statistic for this score ranged from 0.84 to 0.88 across derivation and validation cohorts.

CONCLUSIONS

Our simple scoring system can reproducibly stratify postnephrectomy CKD risk on the basis of readily available parameters. This clinical tool's quantitative assessment of CKD risk may be weighed against other considerations when planning management of kidney tumors and help inform shared decision making between clinicians and patients.

Tumor size and postoperative kidney function following radical nephrectomy

Background: Chronic kidney disease (CKD) following nephrectomy for kidney tumors is common, and both patient and tumor characteristics may affect postoperative kidney function. Several studies have reported that surgery for large tumors is associated with a lower likelihood of postoperative CKD, but others have reported CKD to be more common before surgery in patients with large tumors. Objective: The aim of this study was to clarify inconsistencies in the literature regarding the prognostic significance of tumor size for postoperative kidney function. Study design and setting: We analyzed data from 944 kidney cancer patients managed with radical nephrectomy between January 2012 and December 2013, and 242 living kidney donors who underwent surgery between January 2011 and December 2014 in the Australian states of Queensland and Victoria. Multivariable logistic regression was used to assess the primary outcome of CKD upstaging. Structural equation modeling was used to evaluate causal models, to delineate the influence of patient and tumor characteristics on postoperative kidney function. Results: We determined that a significant interaction between age and tumor size (P=0.03) led to the observed inverse association between large tumor size and CKD upstaging, and was accentuated by other forms of selection bias. Subgrouping patients by age and tumor size demonstrated that all patients aged ≥65 years were at increased risk of CKD upstaging, regardless of tumor size. Risk of CKD upstaging was comparable between age-matched living donors and kidney cancer patients. Conclusion: Larger tumors are unlikely to confer a protective effect with respect to postoperative kidney function. The reason for the previously reported inconsistency is likely a combination of the analytical approach and selection bias.

Incident Chronic Kidney Disease After Radical Nephrectomy for Renal Cell Carcinoma

BACKGROUND

Chronic kidney disease (CKD) after surgery for kidney cancer is common, and is associated with increased morbidity and mortality. This study aimed to identify factors associated with incident CKD in patients managed with radical nephrectomy.

PATIENTS AND METHODS

All patients diagnosed with renal cell carcinoma between January 2012 and December 2013 were ascertained from state-based cancer registries in Queensland and Victoria. Information on patient, tumor, and health service characteristics was obtained via chart review. Multivariable logistic regression was used to evaluate exposures associated with incident CKD (estimated glomerular filtration rate [eGFR] <60 mL per minute per 1.73 m²) at 12 months after nephrectomy.

RESULTS

Older age (adjusted odds ratio [aOR] per 5-year increase, 1.5; 95% confidence interval [CI], 1.4-1.6), male sex (aOR, 1.4; 95% CI, 1.0-2.0), obese compared with not obese (aOR, 1.8; 95% CI, 1.2-2.7), rural compared with urban place of residence (aOR, 1.8; 95% CI, 1.1-3.0) were associated with a higher risk of incident CKD. Lower preoperative eGFR was also associated with a higher risk of incident CKD. Management in private compared with public hospitals was also associated with a higher risk of CKD (aOR, 1.6; 95% CI, 1.2-2.2). Factors related to tumor size and cancer severity were also associated with worse postoperative kidney function, although it is likely this was a consequence of selection bias.

CONCLUSION

Patient characteristics have the strongest associations with incident CKD after radical nephrectomy. Potential risk factors were reasonably similar to recognized CKD risk factors for the general population. Patients who undergo nephrectomy who have CKD risk factors might benefit from ongoing postoperative screening for deterioration of kidney function.

Predictors of new-onset chronic kidney disease in patients managed surgically for T1a renal cell carcinoma: An Australian population-based analysis

BACKGROUND

New-onset chronic kidney disease (CKD) following surgical management of kidney tumors is common. This study evaluated risk factors for new-onset CKD after nephrectomy for T1a renal cell carcinoma (RCC) in an Australian population-based cohort.

METHODS

There were 551 RCC patients from the Australian states of Queensland and Victoria included in this study. The primary outcome was new-onset CKD (eGFR <60 mL/min per 1.73 m² ) and the secondary outcome was new-onset moderate-severe CKD (<45 mL/min per 1.73 m² ). Multivariable logistic regression was used to evaluate associations between patient, tumor and health-service characteristics and these outcomes.

RESULTS

Forty percent (219/551) of patients developed new-onset CKD, and 12% (68/551) experienced new-onset moderate-severe CKD. Risk factors for new-onset CKD were age, lower preoperative eGFR, tumor size >20 mm, radical nephrectomy, lower hospital caseloads (<20 cases/year), and rural place of residence. The associations between rural place of residence and low center volume were a consequence of higher radical nephrectomy rates.

CONCLUSION

Risk factors for CKD after nephrectomy generally relate to worse baseline health, or likelihood of undergoing radical nephrectomy. Surgeons in rural centres and hospitals with low caseloads may benefit from formalized integration with specialist centers for continued professional development and case-conferencing, to assist in management decisions.

Has the association between hysterectomy and ovarian cancer changed over time? A systematic review and meta-analysis

Until recently most studies suggested that hysterectomy with ovarian conservation was associated with a decreased risk of ovarian cancer. However, several recent studies have reported modestly increased risks of ovarian cancer following hysterectomy. Given that as many as 35% of women will have a hysterectomy, the nature of the association requires clarification. We conducted a systematic review and meta-analysis of the published literature on the relationship between hysterectomy and ovarian cancer to investigate whether there has been a temporal change in the association. Twenty observational studies that have reported a quantitative assessment of the association between hysterectomy and risk of histologically-confirmed ovarian cancer were included in the meta-analysis. The overall relative risk (RR) estimate was 0.81 (95% confidence interval (CI) 0.72-0.92) suggesting hysterectomy decreases the risk of ovarian cancer. However, there was significant heterogeneity in the results (I(2) = 74%). Our exploration of sources of heterogeneity and metaregression showed that median year of cancer diagnosis of included cases explained most of the heterogeneity relative risk (RR = 0.70 (95% CI 0.65-0.76) for median year diagnosis pre 2000; RR = 1.18 (95% CI 1.06-1.31) for post 2000). This study shows that there has been a temporal shift in the association between hysterectomy and risk of ovarian cancer. One explanation may be the trend away from hysterectomy in younger women. Other speculative possibilities include the decline in oophorectomy rates and the use of oestrogen-only hormone replacement therapy in hysterectomised women. Until further evidence becomes available, clinicians should not advise women that a hysterectomy without salpingo-oophorectomy will favourably influence their future risk of ovarian cancer.

Exploratory study of the 'weekend effect' for acute medical admissions to public hospitals in Queensland, Australia

AIMS

To determine whether in-hospital deaths of patients admitted through emergency departments with acute exacerbations of chronic obstructive pulmonary disease (COPD), acute myocardial infarction, intracerebral haemorrhage and acute hip fracture are increased by weekend versus weekday admission (the 'weekend effect').

METHODS

We performed a retrospective analysis of statewide administrative data from public hospitals in Queensland, Australia, during the 2002/2003-2006/2007 financial years. The primary outcome was 30-day in-hospital mortality. The secondary outcome of 2-day in-hospital mortality helped determine whether increased mortality of weekend admissions was closely linked to weekend medical care.

RESULTS

During the study period, there were 30 522 COPD, 17 910 acute myocardial infarction, 4183 acute hip fracture and 1781 intracerebral haemorrhage admissions. There was no significant weekend effect on 30-day in-hospital mortality for COPD (adjusted risk ratio = 0.92, 95% CI: 0.81-1.04, P= 0.222), intracerebral haemorrhage (adjusted risk ratio = 1.01, 95% CI: 0.86-1.16, P= 0.935) or acute hip fracture (adjusted risk ratio = 0.78, 95% CI: 0.54-1.03, P= 0.13). There was a significant weekend effect for acute myocardial infarction (adjusted risk ratio = 1.15, 95% CI: 1.03-1.26, P= 0.007). Two-day in-hospital mortality showed similar results.

CONCLUSION

This is the first Australian study on the 'weekend effect' (in a cohort other than neonates), and the first study worldwide to assess specifically the weekend effect among COPD patients. Observed patterns were consistent with overseas research. There was a significant weekend effect for myocardial infarction. Further research is needed to determine whether location (e.g. rural), clinical (e.g. disease severity) and service provision factors (e.g. access to invasive procedures) influence the weekend effect for acute medical conditions in Australia.

National trends in the uptake of laparoscopic resection for colorectal cancer, 2000-2008

OBJECTIVE

To examine the trends in the uptake of laparoscopic resection for colorectal cancer.

DESIGN AND SETTING

Retrospective analysis of Australia-wide data on elective resections for colorectal cancer over the 8 financial years 2000-01 to 2007-08, obtained from the National Hospital Morbidity Database.

MAIN OUTCOME MEASURES

National trends in annual percentage of colorectal resections for cancer that were conducted laparoscopically for each year, stratified by hospitals conducting a high volume of elective resections (40 or more/year) versus a low volume, and by public versus private hospitals.

RESULTS

For all Australian hospitals combined, the percentage of resections for colon cancer conducted laparoscopically increased from 2.4% in 2000-01 to 27.5% in 2007-08. For rectal cancer, this increase was from 1.1% to 21.5%. The largest increases were seen in high-volume private hospitals (colon cancer, 2.7% to 34.1%; rectal cancer, 1.5% to 26.2%), but increases also occurred in high-volume public hospitals (colon cancer, 2.7% to 32.2%; rectal cancer, 0.5% to 20.3%), low-volume private (colon cancer, 3.8% to 27.1%; rectal cancer, 2.4% to 25.5%) and low-volume public (colon cancer, 1.1% to 17.0%; rectal cancer, 0.5% to 13.8%) hospitals.

CONCLUSIONS

The use of laparoscopic resection for colorectal cancer has increased throughout Australian hospitals. Our findings provide the data necessary to ensure adequate resource allocation by the appropriate medical bodies to achieve optimal success in the uptake of laparoscopic resection for colorectal cancer in Australia.

Urban-rural differences in prostate cancer outcomes in Australia: what has changed?

OBJECTIVE

To update our previous analysis of trends for prostate-specific antigen (PSA) testing, prostate cancer incidence, radical prostatectomy and prostate cancer mortality to assess whether men in rural and regional areas of Australia now have more equitable access to prostate cancer services, and improved outcomes.

DESIGN, SETTING AND PARTICIPANTS

Descriptive study using population-based data for Australian men aged 50-79 years from 1982 to the 2008-09 financial year (depending on data availability for each outcome measure).

MAIN OUTCOME MEASURES

Age-standardised rates per 100,000 men and 5-year survival rates.

RESULTS

Overall, rates of PSA screening and radical prostatectomy increased, accompanied by reductions in mortality and improvements in survival throughout Australia. Incidence rates were similar for men in urban and rural areas. However, in the last year of data collection, for men in rural areas compared with urban areas, rates of PSA screening (21,267/100,000 v 24,606/100,000; P < 0.01) and radical prostatectomy (182.2/100,000 v 239.2/100,000; P < 0.01) remained lower, mortality remained higher (56.9/100,000 v 45.8/100,000; P < 0.01), and survival outcomes continued to be poorer (5-year relative survival, 87.7% v 91.4%; P < 0.01).

CONCLUSIONS

With some limitations, these ecological data demonstrate that the use of diagnostic and treatment services among men living in rural areas of Australia remains lower than among their urban counterparts, their survival and mortality outcomes are poorer, and these differentials are continuing. There is an urgent need to explore further the reasons for these differences and to implement changes so these inequalities can be reduced.

Bayesian versus frequentist statistical inference for investigating a one-off cancer cluster reported to a health department

Background

The problem of silent multiple comparisons is one of the most difficult statistical problems faced by scientists. It is a particular problem for investigating a one-off cancer cluster reported to a health department because any one of hundreds, or possibly thousands, of neighbourhoods, schools, or workplaces could have reported a cluster, which could have been for any one of several types of cancer or any one of several time periods.

Methods

This paper contrasts the frequentist approach with a Bayesian approach for dealing with silent multiple comparisons in the context of a one-off cluster reported to a health department. Two published cluster investigations were re-analysed using the Dunn-Sidak method to adjust frequentist p-values and confidence intervals for silent multiple comparisons. Bayesian methods were based on the Gamma distribution.

Results

Bayesian analysis with non-informative priors produced results similar to the frequentist analysis, and suggested that both clusters represented a statistical excess. In the frequentist framework, the statistical significance of both clusters was extremely sensitive to the number of silent multiple comparisons, which can only ever be a subjective "guesstimate". The Bayesian approach is also subjective: whether there is an apparent statistical excess depends on the specified prior.

Conclusion

In cluster investigations, the frequentist approach is just as subjective as the Bayesian approach, but the Bayesian approach is less ambitious in that it treats the analysis as a synthesis of data and personal judgements (possibly poor ones), rather than objective reality. Bayesian analysis is (arguably) a useful tool to support complicated decision-making, because it makes the uncertainty associated with silent multiple comparisons explicit.

Effect of smoking among Indigenous and non-Indigenous mothers on preterm birth and full-term low birthweight

OBJECTIVE

To estimate the percentage of preterm (< 37 weeks) and full-term low-birthweight (37-41 weeks, < 2500 g) babies born to mothers who smoke, stratified by Indigenous status and statistically adjusted for the potential confounding effects of social and demographic factors, medical conditions and pregnancy complications.

DESIGN, SETTING AND PARTICIPANTS

Population-based study of singleton babies born to mothers resident in Queensland who gave birth in Queensland from 1 July 2005 to 31 December 2006.

MAIN OUTCOME MEASURES

Adjusted percentages of preterm birth and full-term low birthweight for babies born to Indigenous and non-Indigenous mothers.

RESULTS

Of the 79 803 babies studied, 4228 (5.3%) were born to Indigenous mothers and 16 395 (20.5%) were born to mothers who smoked during pregnancy. The percentage of Indigenous mothers who smoked (54%) was almost triple that for non-Indigenous mothers (risk ratio, 2.90; 95% CI, 2.81-2.99). The adjusted outcomes for babies born to Indigenous non-smokers were similar to those for non-Indigenous non-smokers (preterm, 7.1% v 6.1%; full-term low birthweight, 1.6% v 1.1%). The adjusted percentages for smokers were high regardless of Indigenous status (preterm, Indigenous v non-Indigenous, 8.3% v 7.8%; full-term low birthweight, Indigenous v non-Indigenous, 5.3% v 3.7%).

CONCLUSIONS

Antenatal smoking remains an important cause of poor health among both Indigenous and non-Indigenous newborn babies. Most pregnant smokers receive their antenatal care in the public sector. State and federal governments, who directly fund this sector, have a particular responsibility to ensure that interventions are offered to all pregnant smokers to help them quit smoking.

Assessment of ambulance dispatch data for surveillance of influenza-like illness in Melbourne, Australia

Objectives

Ambulance dispatch data are collated electronically in many jurisdictions and have a wide reach into the community. They may therefore be useful for syndromic surveillance and early recognition of emerging infectious diseases. This study assessed whether ambulance dispatch data are suitable for influenza surveillance.

Study design

Comparison of a time series of ambulance dispatch data from Melbourne, Australia for the years 1997–2005 with locum service and general practice (GP) sentinel surveillance data for influenza-like illness (ILI).

Methods

All data were aggregated into 1-week periods, corresponding to the data collection period used in the GP sentinel surveillance system, which was used as the reference system. Rates of ambulance dispatches classified to respiratory or breathing problems per 1000 total dispatches were compared with rates of callouts for flu or influenza per 1000 locum calls, and rates of ILI per 1000 patients from the sentinel GPs. Signals from the ambulance data were generated using the log likelihood ratio CUSUM, a method of continuous monitoring suitable for surveillance.

Results

The ambulance dispatch data displayed seasonal trends that were similar to those observed in locum service surveillance and GP sentinel systems, and identified the years with higher-than-expected seasonal ILI activity (1998 and 2003) and the epidemic year (1997). However, there was a high baseline rate of ambulance calls classified to respiratory or breathing problems (90–100 per 1000 calls) in months where there was minimal influenza activity.

Conclusion

Ambulance dispatch data have potential for syndromic surveillance, but because of the high background noise are not definitive and would need to be calibrated to suit particular local circumstances.

Antenatal care implications of population‐based trends in Down syndrome birth rates by rurality and antenatal care provider, Queensland, 1990–2004

OBJECTIVE

To assess whether the rates of Down syndrome births in Queensland vary according to rurality (ie, whether the mother lives in a rural or urban area) and type of antenatal care provider, and to consider any implications for antenatal care.

DESIGN AND SETTING

Population-based study of Down syndrome births in Queensland between 1990 and 2004, stratified by rurality and type of antenatal care provider (private obstetrician, public hospital or shared care).

RESULTS

Since 2000, there has been a large fall in maternal-age-adjusted rates of Down syndrome births among mothers living in urban areas (-14.3% per year; 95% CI, -22.7%, -5.0%) and among mothers receiving their antenatal care from private obstetricians (-27.5% per year; 95% CI, -37.6%, -15.8%). Similar decreases have not occurred among mothers living in rural areas (0.0%; 95% CI, -11.7%, 13.1%) or among mothers receiving antenatal care from public hospitals (+2.9%, 95% CI, -10.3%, 17.9%).

CONCLUSION

Possible reasons for the observed trends include unequal access to antenatal screening; confusion about screening guidelines and protocols; late presentation for antenatal care; and differences in attitudes to screening and termination of pregnancy among expectant parents, such that they may choose not to have screening or not to act on a positive screening test result.

Rates of percutaneous coronary interventions and bypass surgery after acute myocardial infarction in Indigenous patients

OBJECTIVE

To compare rates of percutaneous coronary interventions (PCI) and bypass surgery after acute myocardial infarction (AMI) in Indigenous and non-Indigenous patients.

DESIGN

Cohort study of public-sector patients who were followed up for 1 year using administrative hospital data.

PARTICIPANTS AND SETTING

We followed up 14 683 public-sector patients admitted to Queensland hospitals for AMI between 1998 and 2002. Of these, 558 (3.8%) identified as Indigenous.

OUTCOME MEASURES

Rates of PCI and bypass surgery, adjusted for differences between the Indigenous and non-Indigenous cohorts according to age, sex, socioeconomic status, remote residence, hospital characteristics, and comorbidities.

RESULTS

The adjusted rate for PCI during the index admission was significantly lower by 39% (rate ratio [RR], 0.61; 95% CI, 0.38-0.98) among Indigenous versus non-Indigenous patients with AMI; the adjusted rate for subsequent PCI was significantly lower by 28% (RR, 0.72; 95% CI, 0.54-0.96). Adjusted rates for bypass surgery were similar in the two cohorts. For any coronary procedure (ie, PCI or bypass surgery), the adjusted rate was significantly lower by 22% (RR, 0.78; 95% CI, 0.64-0.94) among Indigenous patients with AMI. Diabetes, chronic renal failure, pneumonia, and chronic rheumatic fever were at least twice as common among Indigenous patients with AMI as in the rest of the cohort, and chronic bronchitis and emphysema and heart failure were at least 60% more common. If a patient had at least one comorbidity, then their probability of having a coronary procedure was reduced by 40%.

CONCLUSIONS

There are likely to be several reasons for the lower rates of coronary procedures among Indigenous patients, but their high rates of comorbidities and the association of comorbidities with lower procedure rates was an important finding. As investment in primary care can reduce the prevalence and severity of comorbidities, we suggest that adequate primary health care is a prerequisite for effective specialist care.

Urban–rural differences in prostate cancer mortality, radical prostatectomy and prostate‐specific antigen testing in Australia

OBJECTIVE

To assess differences in trends for prostate cancer mortality, radical prostatectomy and prostate-specific antigen (PSA) testing for Australian men aged 50-79 years living in capital cities compared with regional and rural areas.

DESIGN

Descriptive, population-based study based on data from official sources from 1985 to the 2002/03 financial year (depending on data availability).

MAIN OUTCOME MEASURES

Age-standardised rates per 100,000 men aged 50-79 years of mortality from prostate cancer, incidence of prostate cancer, PSA tests and radical prostatectomy.

RESULTS

We found a statistically significant and increasing (age-standardised) mortality excess for prostate cancer in regional and rural areas. In 2000-2002 the excess (compared with capital cities) was 21% (95% CI, 14%-29%). Rates of radical prostatectomy in rural and regional Australia were 29% lower (95% CI, 23% lower to 35% lower) than in capital cities. Although PSA testing is common across the whole of Australia, age-standardised rates in 2002/03 were 16% lower (95% CI, 15% lower to 17% lower) in regional and rural areas than in capital cities.

CONCLUSIONS

Our results show that the probability of a man having a PSA test and the management of his prostate cancer depend on where he lives. The cause or causes of the prostate cancer mortality excess in regional/rural areas cannot be established in a descriptive study, but fewer radical prostatectomies in regional and rural areas, perhaps associated with less PSA screening, remain among the several competing hypotheses. Other possibilities are related to other differences in management, perhaps associated with access to urologists. Governments and other budget holders need good evidence about the effectiveness of prostate cancer screening and early treatment, but also about the best strategies for providing equitable access to cancer services in both urban and rural areas.

Ageing and healthcare costs in Australia: a case of policy‐based evidence?

There have been dire predictions that population ageing will result in skyrocketing health costs. However, numerous studies have shown that the effect of population ageing on health expenditure is likely to be small and manageable. Pessimism about population ageing is popular in policy debates because it fits with ideological positions that favour growth in the private sector and seek to contain health expenditure in the public sector. It might also distract attention from the need to evaluate the appropriateness and effectiveness of current patterns of care. Pessimistic scenarios have stifled debate and limited the number of policy options considered. Policy making in Australia would be improved if we took a more realistic view of the effect of population ageing on health expenditure.

International Trends in Prostate-Cancer Mortality: The Decrease is Continuing and Spreading

OBJECTIVE

To measure recent changes in prostate-cancer mortality across 24 developed countries.

METHODS

Mortality data for men aged 50-79 years were obtained from the World Health Organisation mortality database and we assessed trends in age-standardised mortality rates using joinpoint regression models.

RESULTS

Significant reductions in prostate-cancer mortality were observed in United Kingdom, United States, Austria, Canada, Italy, France, Germany, Australia and Spain, and downward trends were also observable in the Netherlands, Ireland and Sweden.

CONCLUSIONS

Mortality declines for prostate cancer are now evident in 12 out of the 24 developed countries considered in this analysis. Increases in PSA screening and better treatment of early-stage disease, possibly acting in combination, remain plausible hypotheses.

Participation in cervical cancer screening by women in rural and remote Aboriginal and Torres Strait Islander communities in Queensland

OBJECTIVE

To investigate the extent of participation in cervical cancer screening among women who live in discrete rural and remote Indigenous communities in Queensland.

DESIGN

Descriptive analysis of data from the Queensland Health Pap Smear Registry for the period March 1999 to February 2001.

SUBJECTS

Women aged 20-69 years who had given their address of usual residence as one of 13 discrete rural and remote Indigenous communities in Queensland.

MAIN OUTCOME MEASURES

Proportion of women who participated in cervical screening over a two-year period ("biennial participation percentage") and variation in participation across the 13 communities.

RESULTS

Overall, the biennial participation percentage in the Indigenous communities was 41.1%. This was 30% lower (risk ratio, 0.70; 95% CI, 0.67-0.72) than that for the rest of Queensland. There was statistically significant variation among communities, with biennial participation percentage ranging from 19.9% to 63.5%.

CONCLUSIONS

The variation in participation across the communities suggests that the problem of low participation among Indigenous women is not intractable. Achieving participation rates similar to the highest rates found in our study would be of major benefit to Indigenous women.

The effects of quality improvement interventions on inhospital mortality after acute myocardial infarction

OBJECTIVE

To evaluate the effects of quality improvement interventions on inhospital mortality after admission for acute myocardial infarction (AMI).

DESIGN

Before-and-after study (with concurrent controls) based on hospital discharge data from a routinely maintained, administrative database.

SETTING

All Queensland public hospitals, July 1991 - June 1999.

STUDY POPULATION

Patients with AMI admitted through the emergency department.

INTERVENTION

Development and promulgation of clinical practice guidelines at one hospital, combined with regular audit and feedback, commencing November 1995.

MAIN OUTCOME MEASURES

Inhospital mortality (adjusted for age, sex and comorbidities) for four-year periods before (1991-92 to 1994-95) and after (1995-96 to 1998-99) initiation of quality improvement interventions.

RESULTS

Before the intervention, the adjusted odds ratio (OR) for inhospital death at the intervention hospital was about the same as at other public hospitals (adjusted OR, 0.99; 95% CI, 0.80-1.24), but was more than 40% lower after the intervention (adjusted OR, 0.59; 95% Cl, 0.45-0.78). After the intervention, the risk of death at the intervention hospital was lower compared with hospitals with cardiologists as admitting practitioners (adjusted OR, 0.63; 95% CI, 0.48-0.83), with onsite revascularisation facilities (adjusted OR, 0.66; 95% CI, 0.49-0.88), and with large numbers (> or = 250 per year) of annual admissions of patients with AMI (adjusted OR, 0.72; 95% CI, 0.54-0.97).

CONCLUSIONS

Quality improvement interventions lower the risk of inhospital death in patients with AMI. Implementation of such interventions in all hospitals may confer a risk of death lower than that achieved by admitting all patients under the care of cardiologists, or to hospitals with revascularisation facilities or a high volume of admissions of patients with AMI.