Statistics

Objective: To determine the prevalence of patient-initiated aggression toward general practitioners in Australia.Design, setting and participants: A cross-sectional national survey, conducted during February – May 2010, of 3090 GPs in 19 Divisions of General Practice, purposively sampled to represent urban, rural and remote areas.Main outcome measure: Proportion of GPs experiencing patient-initiated aggression.Results: Eight-hundred and four GPs returned completed surveys (response rate, 26.3%). In the previous 12 months, 58% of GPs had experienced verbal abuse and 18% had experienced property damage or theft. Very few GPs had experienced physical abuse (6%), stalking (4%), sexual harassment (6%) or sexual assault (0.1%). After controlling for other demographic variables, GPs with fewer years of experience (P = 0.003), or who worked full-time or in larger practices (both P = 0.03) experienced significantly more verbal abuse than their counterparts, and GPs who worked full-time (P = 0.004) or in metropolitan areas (P = 0.01) experienced significantly more property damage or theft. Female GPs experienced significantly more sexual harassment than male GPs (P < 0.001).Conclusions: This is the first national evidence of the prevalence of patient aggression toward GPs in Australia, which could inform the development of policies and guidelines that aim to reduce the prevalence of patient aggression toward GPs.

Laura E Forrest BSc, GradDipGenCouns, PhD · Pushpani M Herath MB BS, MSc · Ian S McRae BSc(Hons), MSc, PhD · Rhian M Parker PhD

Objective: To describe the clinical and epidemiological features of sepsis and severe sepsis in the population of the tropical Top End of the Northern Territory of Australia and compare these with published estimates for temperate Australia, the United States and Europe.Design, setting and participants: Prospective cohort study in the major hospital for tropical NT, a region where 27% of the population are Indigenous. We screened all adult (≥ 15 years) acute hospital admissions over a 12-month period (6 May 2007 – 5 May 2008) for sepsis by standard criteria, and collected standardised clinical data.Main outcome measures: Population-based incidence of community-onset sepsis and severe sepsis requiring intensive care unit (ICU) admission; 28-day mortality rate and microbial epidemiology.Results: There were 1191 hospital admissions for sepsis in 1090 patients, of which 604 (50.7%) were Indigenous people; the average age was 46.7 years. The age-adjusted annual population-based incidence of sepsis was 11.8 admissions per 1000 (mortality rate, 5.4%), but for Indigenous people it was 40.8 per 1000 (mortality rate, 5.7%). For severe sepsis requiring ICU admission, the incidence was 1.3 per 1000 per year (mortality rate, 21.5%), with an Indigenous rate of 4.7 per 1000 (mortality rate, 19.3%).Conclusions: The incidence of sepsis in the tropical NT is substantially higher than that for temperate Australia, the United States and Europe, and these differences are mainly accounted for by the high rates of sepsis in Indigenous people. The findings support strategies to improve housing and access to health services, and reduce comorbidities, alcohol and tobacco use in Indigenous Australians. The burden of sepsis in indigenous populations worldwide requires further study to guide appropriate resourcing of health care and preventive strategies.

Joshua S Davis MB BS, FRACP, PhD · Allen C Cheng MB BS, FRACP, PhD · Mark McMillan RN · Alex B Humphrey · Dianne P Stephens MB BS, FCICM, FANCZA · Nicholas M Anstey MB BS, FRACP, PhD

Objective: To describe the epidemiology of infectious syphilis among Aboriginal and Torres Strait Islander (Indigenous) people in Australia.Design and setting: We assessed trends in national infectious syphilis notification rates from 2005 to 2009 using Poisson regression, with a focus on geographic and demographic differences by Indigenous status. We compared Indigenous and non-Indigenous rate ratios over the study period and summarised the annual changes (summary rate ratio).Main outcome measures: Crude notification rates and summary rate ratios by Indigenous status, jurisdiction, sex, age group and area of residence.Results: From 2005 to 2009, in the Indigenous population, there was a substantial decline in the notification rate for infectious syphilis nationally; as well as in the following subgroups: females, 15–29 year olds, and people living in outer regional and remote areas in the Northern Territory and Queensland. In contrast, there was a significant (P < 0.001) upward trend in the notification rate in the non-Indigenous population nationally; as well as in males, in people aged 20 years and over, and in residents of metropolitan and regional areas, New South Wales, Queensland, South Australia, Victoria and Western Australia. The highest summary rate ratios were seen in remote/very remote areas (86.33; 95% CI, 57.45–129.74), in 15–19 year olds (64.65; 95% CI, 51.12–81.78), in females (24.59; 95% CI, 19.73–30.65), and in Western Australia (23.89; 95% CI, 19.82–28.82).Conclusion: These data demonstrate that Australia has two distinct patterns of infectious syphilis: a substantially declining occurrence in Indigenous remote communities and an increasing incidence in males residing in urban and regional areas. Given the decline in notification rates in Indigenous remote communities, now might be the right time to move toward eliminating infectious syphilis from Indigenous communities.

James S Ward BA · Rebecca J Guy BAppSc, MAppEpid, PhD · Snehal P Akre MB BS, MPH · Melanie G Middleton BMedSc, MPH · Carolien M Giele RN, BSc(Hons), MPH · Jiunn Y Su MB, MPH · Craig A Davis MAE, MAppSc, BA · Handan Wand MA, MSc, PhD · Janet B Knox MB BS, MMed(STI/HIV), DTM · Patricia S Fagan MB BS, MPH, FAFPHM · Basil Donovan MD, MB BS · John M Kaldor PhD · Darren B Russell MB BS, FRACGP, DipVen

Objective: To evaluate the effectiveness of redesigning and streamlining perioperative services.Design: A before-and-after evaluation, with retrospective analysis of de-identified administrative data.Setting: A major tertiary hospital, Melbourne, Australia.Participants: Patients undergoing elective surgery, February 2005 – February 2010.Intervention: Implementing a process redesign to streamline clinical pathways for elective surgery, with a focus on the patient journey from referral to discharge, and establishing a separate, dedicated elective surgery facility.Main outcome measures: Numbers of patients waiting beyond national recommended waiting times for elective surgery; hospital-initiated postponement (HIP) rates for elective surgery; and lengths of stay (LOS), both combined and for specific diagnostic-related groups.Results: The clinical process redesign resulted in a sustained downward trend in the number of elective surgery patients waiting longer than national recommended maximum waiting times. HIP rates were reduced to 1% in the dedicated elective surgery facility, and there was a significant reduction in the combined LOS, as well as the LOS for the most common surgical procedures (P < 0.001).Conclusions: Clinical process redesign of perioperative services and collocation of a separate elective surgery centre improved (i) timeliness of care for elective surgery patients and (ii) key indicators (LOS and HIP rates) for planned elective admissions.

Judy A Lowthian MPH, BAppSc(SpPath), LMusA · Andrea J Curtis BSc(Hons), PhD · Bernadette L Comitti DipAppSc(Nsg), GradDipBusinessAdmin · Peter A Cameron MB BS, MD, FACEM · Martin J Keogh GradDipCritCareNsg, GradDipManagement · William R Johnson MD, FRACS, FRCS · James Tomlinson MB BS, FRACP, FANZCA · Andrew M Stripp BBehavSc(Hons), MSc(ClinPsych)

Two contributions to this issue of the Journal indicate that there is a significant disparity between the research being undertaken in this country and the burden of disease we actually experience. These articles raise important issues about the guidance, funding and facilitation of research. Dear and colleagues (→ Landscape of cancer clinical trials in Australia: using trial registries to guide future research) report that there is a mismatch between the clinical burden of different cancers and the number of trials dedicated to studying them. Specifically, breast cancer is overrepresented in clinical trial activity, while other cancers including lung, colorectal, prostate and pancreatic cancers are underrepresented. Industry sources sponsor 43% of all trials (and 64% of drug trials), with a pronounced tendency toward involvement with randomised controlled trials of systemic interventions (drugs or biological agents) for patients with advanced (metastatic) disease. In an accompanying editorial, Olver (→ Cancer clinical trials in Australia) points out that this is a worldwide trend that at least partly reflects the pressure for pharmaceutical companies to study treatments that stand a good chance of showing a benefit in the relatively short term (eg, increasing life expectancy for a patient with advanced cancer), which can be readily translated into a marketable intervention. Other factors, such as the impact of consumer sentiment, may also have a significant influence on the number of trials funded in specific fields — breast cancer treatment, for example. Olver discusses the need to reverse the declining level of clinical trial activity in Australia and to better target clinical trials to the burden of disease in the community. Widespread participation in clinical research, by patients and doctors, should be fundamental to the practice of medicine in Australia (MJA 2011; 194: 59-60) — it is considered increasingly important in undergraduate and postgraduate training and is a requirement for academic advancement. While it is vital to learn research methodology, there is a central issue that should be addressed before commencing trial planning: Is the study needed? Clinical trial registries were established in 2005 in an attempt to eliminate publication bias towards studies with positive results (MJA 2004; 181: 293-294). The articles by Dear et al and Olver indicate that there is also a potential role for these registries in guiding the direction of research in our community. This suggests the need for a body to ease the difficult task of coordinating research groups and funders so that available research funds are spent optimally. As an example of this, the National Cancer Institute in the United States is planning to create a “cross-disease panel” that will establish priorities for funding and coordination of clinical trials. Pharmaceutical industry investment in clinical trials in Australia is important, but it needs to be more adequately complemented by appropriate investment from the public sector to support independent trial groups, hospital-based research and trials that improve care but which may not translate into marketable interventions.

Annette G Katelaris MB BS, MPH, FRACGP

Objective: To quantify and describe current cancer clinical trial activity in Australia and help guide future trials research using trial registries.Design and setting: Data from cancer trials recruiting in Australia at 31 March 2009 were extracted from the Australian New Zealand Clinical Trials Registry and ClinicalTrials.gov. A regression model was used to identify factors associated with industry sponsorship.Main outcome measures: The proportion of cancer trials compared with estimated burden of disease for each cancer.Results: There were 368 interventional cancer trials open to recruitment. The most-researched cancer was breast cancer, accounting for 17% of trials. Only 7% of trials were in lung cancer, yet lung cancer is responsible for the greatest burden of disease. Industry was the primary sponsor in 43% of trials. Drug treatments were tested in most trials (69%). Trials were more likely to be industry sponsored if they tested systemic rather than local treatments (OR, 16.71; 95% CI, 4.70–59.43), included patients with advanced rather than early disease (OR, 3.76; 95% CI, 1.78–7.94) and used random rather than non-random allocation (OR, 1.78; 95% CI, 1.06–3.00).Conclusion: There is variation in the number of trials according to cancer site, with some cancers being underrepresented relative to their burden of disease. Industry sponsorship is more likely for trials that investigate systemic therapy, recruit patients with advanced disease and are randomised.

Rachel F Dear MB BS, FRACP · Alexandra L Barratt MB BS, MPH, PhD · Kevin McGeechan BSc, MBiostatistics · Lisa Askie PhD, MPH · John Simes MD, FRACP · Martin H N Tattersall MD, MSc, FRACP

Objective: To audit general paediatric outpatient practice in Australia, including consultation characteristics and management patterns, diagnoses, factors associated with diagnoses, and billing practices.Design, setting and participants: In October – November 2008, members of the Australian Paediatric Research Network (APRN; a national network of paediatricians established to facilitate multisite secondary care research) were invited to prospectively complete brief standardised data collection forms for 100 consecutive patients or all patients during a 2-week period, whichever came first.Main outcome measures: Length of consultation and type of diagnoses made; proportions recorded as having medications, investigations or referral; odds ratios for factors associated with diagnoses; and proportions of Medicare items billed.Results: Of 300 APRN members, 199 (66%) completed data forms for 8345 consultations in which 15 375 diagnoses were made (mean, 1.8 diagnoses per consultation); 46.0%, 30.9% and 22.8% of consultations involved 1, 2 and ≥ 3 diagnoses, respectively. New and review consultations lasted a mean of 41 (SD, 20) and 26 (SD, 15) minutes, respectively. The most common diagnoses were attention deficit hyperactivity disorder (18.3%), baby checks (9.1%), and learning difficulties (7.5%). Patients seen in 47.5% of consultations had medications (eg, prescriptions, vaccinations) recorded, and patients in 27.2% of consultations were referred elsewhere, usually to a subspecialist or psychologist (31.6% and 26.6% of referrals, respectively). Male sex of the child and owning a Health Care Card were associated with most developmental–behavioural diagnoses. Paediatricians tended to bill for single disease/non-complex consultations, even when seeing a child with multiple problems.Conclusions: Australian paediatricians see children with a range of diagnoses that are often multiple and complex. Our findings provide directions for future secondary care research, and may inform workforce planning and paediatricians’ training requirements.

Harriet Hiscock MB BS, FRACP, MD · Gehan Roberts MB BS, FRACP, PhD · Daryl Efron MB BS, FRACP, MD · Jillian R Sewell MB BS, FRACP · Hannah E Bryson BA(Hons) · Anna M H Price BA(Hons) · Frank Oberklaid MD, FRACP, DCH · Michael South FRACP, MD, FCIM · Melissa A Wake MB ChB, FRACP, MD

CorrectionIncorrect confidence intervals: In “When do I know I am cured? Using conditional estimates to provide better information about cancer survival prospects” in the 17 January 2011 issue of the Journal (Med J Aust 2011; 194: 73-77), there were several minor errors in the 95% confidence intervals given in Box 1: Conditional 5-year relative survival estimates, by type of cancer and number of years after diagnosis, for patients aged 15–89 years at diagnosis, Queensland 1998–2007. These errors applied to survival estimates for stomach cancer, pancreatic cancer, lung cancer, kidney cancer, bladder cancer, non-Hodgkin lymphoma and leukaemia. The 95% CIs have been corrected in the online version of the article, and can be seen at: http://www.mja.com.au/public/issues/194_02_170111/baa10523_fm.html.

Peter D Baade · Danny R Youlden · Suzanne K Chambers

Objective: To describe the proportion of 16–29-year-olds tested for chlamydia by Australian general practitioners in a 12-month period.Design and setting: Between October 2007 and September 2008, the national chlamydia testing rate in 16–29-year-olds was calculated by dividing the number of Medicare-reimbursed chlamydia tests by two denominators: (i) Medicare-reimbursed GP consultations; and (ii) estimated resident populations adjusted for the proportion who were sexually active.Main outcome measures: GP chlamydia testing rates in 16–29-year-olds per 100 patients attending a GP consultation and per 100 sexually active population, by patient age and sex, state/territory of residence, and remoteness area.Results: Among the estimated Australian population of 16–29-year-olds, 85.6% of females and 64.4% of males had at least one GP consultation in the 12-month period. The national GP chlamydia testing rate per 100 patients was 8.9% (95% CI, 8.88%–8.94%). The national GP chlamydia testing rate per 100 sexually active population was 8.0% (95% CI, 7.92%–7.98%). The rate per 100 sexually active population was higher in females (12.5%) compared with males (3.7%) (P < 0.01); higher in 20–24-year-olds (9.0%) compared with 16–19-year-olds (8.7%) and 25–29-year-olds (6.6%) (P < 0.01); higher in those living in non-metropolitan areas (11.0%) compared with metropolitan areas (8.4%) (P < 0.01); and highest in those living in the Northern Territory (21.4%) compared with other jurisdictions (P < 0.01).Conclusions: Despite clinical guidelines recommending annual chlamydia testing for sexually active 15–29-year-olds, our analysis showed that a high proportion of young people aged 16–29 years attend a GP each year, but few of the sexually active population in this age group were tested for chlamydia in general practice. Strategies are needed to support GPs to enhance chlamydia testing in young people.

Fabian Y S Kong BPharm, MEpi · Rebecca J Guy BAppSc, MAppEpid, PhD · Jane S Hocking MPH, MHthSc(PHP), PhD · Tony Merritt MB BS, MPH · Marie Pirotta MB BS, FRACGP, PhD · Clare Heal MB ChB, FRACGP, PhD · Isabel Bergeri PharmD, MSc, DTMPH · Basil Donovan MD, FRCPI, FAChSHM · Margaret E Hellard MB BS, FRACP, PhD

Omission: In “Detecting undiagnosed diabetes using glycated haemoglobin: an automated screening test in hospitalised patients” in the 21 February 2011 issue of the Journal (Med J Aust 2011; 194: 160-164), the following were omitted:

Nyoli A Valentine MB BS · Tariq M Alhawassi BScPharm, MClinPharm · Greg W Roberts BPharm, FSHP, BCPS · Parind P Vora MB BS, MPH · Stephen N Stranks MB BS, FRACP · Matthew P Doogue MB ChB, FRACP

Objective: To assess the utility of glycated haemoglobin (HbA1c) level as an automated screening test for undiagnosed diabetes among hospitalised patients and to estimate the prevalence of undiagnosed diabetes among hospitalised patients.Design, participants and setting: A 3-month prospective study of all adult patients admitted to a tertiary hospital. An HbA1c test was automatically undertaken on admission for all patients with a random plasma glucose (RPG) level ≥ 5.5 mmol/L. Demographic, admission and biochemical data were obtained from hospital databases. A subset of patients was recruited for an oral glucose tolerance test (OGTT) after discharge.Main outcome measures: Prevalence of undiagnosed diabetes (defined as HbA1c ≥ 6.5% in accordance with International Expert Committee and American Diabetes Association recommendations) and utility of automated HbA1c testing.Results: The prevalence of undiagnosed diabetes was 11% (95% CI, 9.8%–12.4%) (262/2360) during the study period. A further 312 patients with known diabetes were admitted. The prevalence of undiagnosed diabetes was highest in the 65–74-years age group. The HbA1c test cost was $152 per new diagnosis of diabetes. Conservatively assuming an annual incidence of undiagnosed diabetes of 0.8%, the ongoing cost of testing hospitalised patients would be $2100 per new diagnosis of diabetes. RPG testing was not sensitive or specific in diagnosing diabetes. Patients were poorly compliant with the post-discharge OGTT (27% completion rate).Conclusions: HbA1c is a simple, inexpensive screening test that can be automated using existing clinical blood samples. Hospital screening for diabetes needs to be coupled with resources for management in the community.

Nyoli A Valentine MB BS · Tariq M Alhawassi BScPharm, MClinPharm · Greg W Roberts BPharm, FSHP, BCPS · Parind P Vora MB BS, MPH · Stephen N Stranks MB BS, FRACP · Matthew P Doogue MB ChB, FRACP

Objective: To determine the iodine status of participants in the Aboriginal Birth Cohort Study who resided in the Darwin Health Region (DHR) in the “Top End” of the Northern Territory prior to the introduction of mandatory iodine fortification of bread.Design, setting and participants: Participants in our study had been recruited at birth and were followed up at a mean age of 17.8 years. Spot urine samples were collected and assessed for iodine concentration at a reference laboratory. The median urinary iodine concentration (MUIC) of residents of the DHR was calculated and compared with international criteria for iodine status. Analyses were conducted for subgroups living in urban areas (Darwin–Palmerston) and remote communities (rural with an Aboriginal council). We collected a repeat sample in a subset of participants to explore the impact of within-person variation on the results.Main outcome measure: MUIC for residents of the DHR.Results: Urine specimens were provided by 376 participants in the DHR. Overall MUIC was 58 μg/L when weighted to the 2006 Census population. Urban boys had higher values (MUIC = 77 μg/L) than urban and remote-dwelling non-pregnant girls (MUIC = 55 μg/L), but all these groups were classified as mildly iodine deficient. Remote-dwelling boys had the lowest MUIC (47 μg/L, moderate deficiency). Pregnant girls and those with infants aged less than 6 months also had insufficient iodine status. Correction for within-person variation reduced the spread of the population distribution.Conclusions: Previously, iodine deficiency was thought to occur only in the south-eastern states of Australia. This is the first report of iodine deficiency occurring in residents of the NT. It is also the first study of iodine status in a defined Indigenous population. Future follow-up will reassess iodine status in this group after the introduction of iodine fortification of bread.

Dorothy E M Mackerras MPH, PhD · Gurmeet R Singh MPH · Creswell J Eastman MD, FRACP, FRCPA

Objective: To determine the predictive value of the ABCD2 score for early risk of stroke in Australian patients who have had transient ischaemic attack (TIA).Design, participants and setting: Cohort study of 512 consecutive patients with suspected TIA referred by the emergency department to the acute stroke unit (in accordance with the TIA pathway) of an urban tertiary hospital in Melbourne, Victoria, between 1 June 2004 and 30 November 2007.Main outcome measures: Overall accuracy, estimated by the area under the curve (AUC) of receiver operating characteristic plots (of true positive rate v false positive rate), and sensitivity, specificity, predictive values and likelihood ratios at prespecified cut-off ABCD2 scores for stroke within 2, 7 and 90 days.Results: 24 patients were excluded because their symptoms lasted more than 24 hours. All included patients were reviewed by a stroke physician; TIA was confirmed in 301/488 (61.7%). Most (289/301; 96.0%) had complete follow-up. Stroke occurred in 4/292 patients (1.37%; 95% CI, 0.37%–3.47%) within 2 days and 7/289 (2.42%; 95% CI, 0.98%–4.93%) within 90 days; no patient had a stroke between 2 and 7 days. The AUCs for stroke in patients with confirmed TIA were 0.80 (95% CI, 0.68–0.91) and 0.62 (95% CI, 0.40–0.83) for stroke within 2 days and 90 days, respectively. At a cut-off of ≥ 5, the ABCD2 score had modest specificity for stroke within 2 days (0.58) and 90 days (0.58), but positive predictive values (2 days, 0.03; 90 days, 0.04) and positive likelihood ratios (2 days, 2.40; 90 days, 1.71) were both poor. The score performed similarly poorly at other prespecified cut-off scores.Conclusions: Given its poor predictive value, the use of the ABCD2 score alone may not be dependable for guiding clinical treatment decisions or service organisation in an Australian tertiary setting. Validation in other Australian settings is recommended before it can be applied with confidence.

Lauren M Sanders MB BS · Velandai K Srikanth FRACP, PhD · Helen Psihogios FACEM · Kitty K Wong SRN, MPH · David Ramsay RN · Thanh G Phan FRACP, PhD

Objective: To report the latest conditional survival estimates for patients with cancer in Queensland, Australia.Design, setting and participants: Descriptive study of state-wide population-based data from the Queensland Cancer Registry on patients aged 15–89 years who were diagnosed with invasive cancer between 1982 and 2007.Main outcome measure: Conditional 5-year relative survival for the 13 most common types of invasive cancer, and all cancers combined.Results: The prognosis for patients with cancer generally improves with each additional year that they survive. A significant excess in mortality compared with the general population ceases to occur within 10 years after diagnosis for survivors of stomach, colorectal, cervical and thyroid cancer and melanoma, with these groups having a conditional 5-year relative survival of at least 95% after 10 years. For the remaining cancers we studied (pancreatic, lung, breast, prostate, kidney, and bladder cancer, non-Hodgkin lymphoma, and leukaemia), conditional 5-year relative survival estimates (at 10 years after diagnosis) ranged from 82% to 94%, suggesting that patients in these cohorts continue to have poorer survival compared with the age-matched general population.Conclusions: Estimates of conditional survival have the potential to provide useful information for cancer clinicians, patients and their carers as they are confronted by personal and surveillance-related decisions. This knowledge may be effective in building realistic hope and helping people manage uncertainty about the future. We suggest that measures of conditional survival be incorporated into routine statistical reporting in Australia.

Peter D Baade PhD · Danny R Youlden BSc · Suzanne K Chambers PhD

Objective: To model the impact of both population and high-risk strategies on cardiovascular disease (CVD) outcomes.Design, setting and participants: A CVD risk-factor survey was carried out in rural south-eastern Australia from 2004 to 2006. Using a stratified random sample, data for 1116 participants aged 35–74 years were analysed. Applying the Framingham risk equations to risk-factor data, 5-year probabilities of a coronary heart disease event, stroke and cardiovascular event were calculated. The effect of different changes in risk factors were modelled to assess the extent to which cardiovascular diseases can be prevented by changing the risk factors at a population level (population strategy), among the high-risk individuals (high-risk strategy) or both.Results: Among men, a population strategy could reduce cardiovascular events by 19.3% (193 per 1000 per 5 years), the high-risk strategy by 12.6% (126 per 1000) and a combined strategy by 24.1% (241 per 1000); and among women, by 21.9% (219 per 1000), 19.0% (190 per 1000) and 28.7% (287 per 1000), respectively.Conclusions: For prevention of CVD in Australia, it is important both to treat high-risk individuals and to reduce the mean risk-factor levels in the population. We show how risk-factor survey data can be used to set targets for prevention and to monitor progress in line with the recommendations of the National Preventative Health Taskforce.

Erkki A Vartiainen MD, PhD · Tiina Laatikainen MD, PhD · Benjamin Philpot BSc · Edward D Janus MD, PhD · Nathalie Davis-Lameloise PhD · James A Dunbar MD, FRACGP

Objective: To quantify and characterise the reports of syncope and seizures following quadrivalent (4v) human papillomavirus (HPV) vaccination.Design and setting: Retrospective case series of notifications to SAEFVIC (Surveillance of Adverse Events Following Vaccination In the Community), May 2007 – April 2009.Main outcome measures: Incidence of syncope and seizure following 4vHPV vaccination; clinical outcomes.Results: 97/1653 SAEFVIC reports met the study criteria: afebrile seizures (3), syncopal seizures (31) and syncope alone (63). Median age at vaccination was 15 years (range, 8–26 years). Injuries were reported in seven cases, including one vertebral fracture. A SAEFVIC clinic review was undertaken in 41% (40/97) and 22 patients received further 4vHPV vaccine doses administered supine, with no recurrences. The reporting rate after 4vHPV vaccine for syncope and syncopal seizures was 7.8/100 000 and 2.6/100 000 doses distributed, respectively.Conclusion: Syncope and syncopal seizures occurred after 4vHPV vaccination in Victoria at rates similar to those seen internationally. Clinical review allowed clarification of the diagnosis and management, including safe administration of further doses under supervision.

Nigel W Crawford · Hazel J Clothier MEpid · Sonja Elia RN · Teresa Lazzaro MB BS · Jenny Royle MB BS, MD · Jim P Buttery MB BS, MSc

Objective: To describe recent trends among men who have sex with men (MSM) in age at diagnosis of HIV in Victoria.Design and setting: Analysis of Victorian HIV surveillance data from (i) passive surveillance (2000–2009) and (ii) the Victorian Primary Care Network for Sentinel Surveillance (VPCNSS) (2006–2009). Age-trend comparisons were made using syphilis and gonorrhoea enhanced surveillance.Main outcome measures: HIV diagnoses, HIV testing and behavioural indicators by year and age group among MSM.Results: Following a period of sustained increase between 2000 and 2007, the median age at HIV diagnosis among MSM declined significantly, from 38.8 years in 2007 to 35.3 years in 2008 (P = 0.023), remaining at 35.9 years in 2009. Between 2007 and 2008, the median age of syphilis and gonorrhoea notifications also declined, from 40.6 to 36.0 years and from 32.3 to 29.3 years, respectively. The median age of HIV testing among MSM in the VPCNSS population remained constant between 2006 and 2009, at 33.0 years. Compared with older MSM, those aged less than 35 years were more likely to have never previously been tested for HIV (relative risk [RR], 1.36 [95% CI, 1.30–1.41]); to not know the HIV status of their regular partner (RR, 1.11 [95% CI, 1.01–1.21]); and to report inconsistent condom use with casual partners (RR, 1.07 [95% CI, 1.01–1.14]) and regular partners (RR, 1.07 [95% CI, 1.00–1.14]).Conclusions: Younger MSM in Victoria may be at increasing risk of HIV infection. Enhanced methods of monitoring HIV and sexually transmitted infection transmission in younger MSM are needed, as well as prevention messages to target this group, who may not fully understand their HIV risk.

Carol El-Hayek BSc, MEpi · Isabel Bergeri PharmD, MScEpi · Margaret E Hellard FAFPHM, FRACP, PhD · Alisa E Pedrana BBiomedSc(Hons) · Nasra Higgins MEpi · Alan Breschkin PhD · Mark Stoové PhD

Objective: To evaluate the 2010 “Anatomy by whole body dissection” course, a 7-week elective course offered to senior medical students at the University of Sydney at the end of their third year.Design, setting and participants: In the 2010 course, 29 students divided into eight groups carried out whole-body dissections on eight cadavers over a 34-day period. Surgical trainees acted as demonstrators, and surgeons and anatomists as supervisors. The students were assessed by practical tests involving the identification of 20 tagged structures in four wet specimens before, during, at the end of, and 1 month after the course. In addition, students were asked to complete an anonymous feedback questionnaire about the course.Main outcome measure: Acquisition of topographical anatomical knowledge, and student feedback on the usefulness of the course.Results: A significant increase in topographical clinical anatomical knowledge was demonstrated among the participants and was maintained in the short term. The median pre-course assessment score was 8/20 (interquartile range [IQR], 4) and the median post-course assessment score was 19/20 (IQR, 1). This difference was statistically significant (P < 0.001). All students rated the course as “very good”, and unanimously recommended that the course be available to all students as part of the medical curriculum.Conclusion: Students’ knowledge of anatomy improved significantly between the pre-course and post-course assessments, and all students rated the course very favourably. This supports our view that dissection anatomy should be an integral component of medical education.

George Ramsey-Stewart MD, FRCS, FRACS · Annette W Burgess MBT, MEd, MMedEd · David A Hill MB MS, FRCS, FRACS

Objective: To describe the clinical features and laboratory findings in patients with definite red-bellied black snake (RBBS; Pseudechis porphyriacus) bites, including correlation with results of venom assays. Design, patients and setting: Prospective cohort study of patients with definite RBBS bites, recruited to the Australian Snakebite Project from January 2002 to June 2010. Main outcome measures: Clinical and laboratory features of envenoming; peak venom concentrations and antivenom treatment. Results: There were 81 definite RBBS bites; systemic envenoming occurred in 57 patients (70%) and local envenoming alone occurred in one patient. Systemic envenoming was characterised by local envenoming in 55 patients (96%), systemic symptoms in 54 patients (95%), anticoagulant coagulopathy with a raised activated partial thromboplastin time (aPTT) in 35 patients (61%) and myotoxicity in seven patients (12%). One patient required non-invasive ventilation for severe myotoxicity that resulted in muscle weakness. Three patients developed local ulceration. There were no deaths. Twenty-two envenomed patients (39%) received tiger snake or black snake antivenom, and administration within 6 hours of the bite was associated with normalisation of the aPTT. Eight patients (36%) had immediate hypersensitivity reactions to antivenom, including one case of anaphylaxis. The median peak venom concentration in 37 systemically envenomed patients with serum available was 19 ng/mL (interquartile range, 12–50 ng/mL; range, 3–360 ng/mL), which did not correlate with clinical severity. In 17 patients who received antivenom and had venom concentration measured, no venom was detected in serum after the first antivenom dose, including nine who were given one vial of tiger snake antivenom. Conclusion: RBBS envenoming caused local effects, systemic symptoms, anticoagulant coagulopathy and, uncommonly, myotoxicity. One vial of tiger snake or black snake antivenom appears to be sufficient to remove venom and neutralise reversible effects, but hypersensitivity reactions occurred in over a third of patients.

Andrew Churchman BM BS(Hons) · Margaret A O’Leary PhD · Nicholas A Buckley BMed, FRACP, MD · Colin B Page MB ChB, FACEM, MMedSci(Clin Epi) · Alan Tankel BSc, MB ChB, FACEM · Chris Gavaghan MB BS, FACEM · Anna Holdgate MB BS, FACEM, MMed · Simon G A Brown MB BS, FACEM, PhD · Geoffrey K Isbister BSc, FACEM, MD

To the Editor: Paul, the 2-year-old octopus of Oberhausen Sea Life Aquarium, Germany, gained celebrity status over the course of the 2010 International Federation of Association Football (FIFA) World Cup by predicting winners with surprising accuracy. In order to make a prediction, Paul was offered food from two separate containers, each one featuring the respective team’s flag. Whichever container Paul chose to eat from first was deemed to be the predicted winner. During the World Cup, Paul correctly predicted all of Germany’s results, as well as the eventual winner, Spain. In other words, this cephalopod made correct predictions eight times in a row. Suppose that before the beginning of the World Cup we hypothesised that Paul would correctly predict the results of eight football matches, including the grand final (H1). The null hypothesis (H0) would have been that Paul could not correctly make these predictions — that is, he was not psychic. Assuming a probability of 0.5 of correctly predicting a result (ie, a 50 : 50 chance), then the probability of predicting eight games in a row is 1 in 256 (1/28), or about 0.004. As Paul did correctly make these predictions, there is strong evidence to reject the null hypothesis. Using an exact 95% confidence interval to generate a prediction interval, the best we can say about the probability that Paul was psychic is that it is > 63% and ≤ 100%. Therefore, should we assume Paul was psychic based on P = 0.004, or has something else happened? The most likely explanation is that a type 1 error occurred — we rejected the null hypothesis when it was true, because a P value (significance level) of 0.004 still allows a chance finding of a statistical difference to occur in 0.4% of tests. Interestingly, in clinical practice we often accept P values that indicate less significant results than this (ie, P > 0.004 but < 0.05), so type 1 errors may occur more often than we realise. Of course, there are several problems with our analysis. First, we were already aware of the outcome when we conducted the analysis, so our probability for each successful prediction should have been 1 and not 0.5. This is an example of post-hoc probability analysis. Second, it was not an ideal scientific experiment because there was no control group, only one test was performed per match, there may have been differences in food preparation, and so on. Finally, it is not wise to conduct statistical analysis on implausible events, as this increases the probability of type 1 errors. We do not believe that Paul had psychic powers, but his predictions do serve as a good example that type 1 errors can never be ruled out, even with highly significant results.

Lydia M McGee · Richard G E McGee

Objectives: To explore the perceived impact of medicolegal concerns on how Australian doctors practise medicine and to compare doctors who have experienced a medicolegal matter with those who have not.Design and setting: Cross-sectional survey (posted in September 2007, with reminder 4 weeks later) of Australian doctors from all major specialty groups, trainees and a sample of general practitioners who were insured with a medical insurance company.Participants: 2999 respondents of 8360 who were sent the survey.Main outcome measures: Perceived practice changes due to concerns about medicolegal issues, beliefs about medicolegal issues, and the influence of medicolegal issues on both career choices and how doctors relate to their patients.Results: Respondents reported changes in practice behaviour due to medicolegal concerns, with 43% of doctors stating that they referred patients more than usual, 55% stating that they ordered tests more than usual, and 11% stating that they prescribed medications more than usual. Respondents also reported improved communication of risk (66%), increased disclosure of uncertainty (44%), developed better systems for tracking results (48%) and better methods for identifying non-attenders (39%) and for auditing clinical practice (35%). Concerns about medicolegal issues led to 33% considering giving up medicine, 32% considering reducing their working hours and 40% considering retiring early. These proportions were all significantly greater for doctors who had previously experienced a medicolegal matter compared with those who had not.Conclusions: This Australian study, like international studies, confirms that doctors’ concerns about medicolegal issues impact on their practice in a variety of ways. There is a greater perceived impact on those doctors who have previously experienced a medicolegal matter.

Louise M Nash MB BS(Hons), BA, FRANZCP · Merrilyn M Walton BA, MSW, PhD · Michele G Daly BSc(Hons), MSc · Patrick J Kelly BMath(Hons), PhD · Garry Walter BMedSc, PhD, FRANZCP · Elizabeth H van Ekert BA, DipEd, MMedHum · Simon M Willcock MB BS, PhD · Christopher C Tennant MD, MPH, FRANZCP

Objective: To examine cancer incidence and mortality in Indigenous Queenslanders.Design, setting and patients: Assessment of indirectly standardised incidence and mortality ratios for Indigenous Australians in Queensland diagnosed with cancer from 1997 to 2006, compared with the total Queensland population.Main outcome measures: Standardised incidence and mortality ratios.Results: Compared with the total Queensland population, Indigenous Queenslanders had a lower overall incidence of cancer (standardised incidence ratio, 0.79; 95% CI, 0.75–0.82), but a higher incidence of some of the more fatal cancer types. Overall cancer mortality was higher (standardised mortality ratio, 1.36; 95% CI, 1.28–1.45) and similar to rates for Indigenous people in other Australian states.Conclusion: Cancer rates for Indigenous Queenslanders, a mostly urbanised population, are similar to rates for Indigenous Australians mostly living in remote areas.

Suzanne P Moore BHSc(Nursing), MPH, PhD · Peter K O’Rourke BSc(Hons) BA(Hons), PhD · Kylie-Ann Mallitt BSc(Hons) · Gail Garvey BEd, MEd · Adèle C Green MB BS, MSc, PhD · Michael D Coory MB BS, PhD, FAFPHM · Patricia C Valery MD, MPH, PhD

To the Editor: It is incorrect for Chong and colleagues to state that “during the financial year 2006–07, 32 777 people were admitted to hospital in Australia due to road crashes”. It is also wrong for them to claim “it is often not clear how many of these road crashes are traffic crashes, and how many are non-traffic crashes”.1 Henley and Harrison report that there were 52 066 people seriously (but not fatally) injured due to land transport injury in 2006–07, and 32 777 of these (63.0%) occurred in traffic (on-road) accidents.2 A further 13 639 (26.2%) land transport injury cases in that year were explicitly described as non-traffic (off-road) accidents. The National Injury Surveillance Unit of the Australian Institute of Health and Welfare regularly publishes transport injury-specific analyses, including reports on land transport injuries (both traffic and non-traffic), rail-related transport injuries and transport injuries involving Indigenous Australians. The most recent of these reports is Henley and Harrison’s.2 In addition to the statistics mentioned above, they also report that the national age-standardised rate of non-traffic transport injuries was 66.5 per 100 000 population. In the previous year, this rate was 67.2 per 100 000 population.3 The next report in this series, to be published shortly, will include analysis of national trends in the rate of non-traffic transport injuries over the period 2000–01 to 2007–08.

Clare E Bradley · James E Harrison · Geoffrey I Henley

In reply: We acknowledge our error in reporting Henley and Harrison’s findings,1 and commend Bradley and colleagues for providing information about traffic and non-traffic transport injuries separately. We are also pleased that the National Injury Surveillance Unit will soon publish a report including analysis of trends in non-traffic transport injuries, extending our analyses beyond New South Wales. This is consistent with our conclusion that more needs to be done to understand non-traffic crashes.2 We defend our claim that the statistics in many reports and articles often do not clearly distinguish between traffic and non-traffic crashes and injuries.

Shanley S S Chong · Wei Du · Julie Hatfield

To the Editor: An editorial by Stewart alludes to the problem of silent multiple comparisons when interpreting P values from cancer cluster investigations.1 Visible multiplicities such as occur with pre-specified subgroup analyses or sequential monitoring of trials are difficult enough, but at least in these circumstances we know how many multiple comparisons are under consideration. More difficult are silent multiplicities such as occur with cluster investigations (and also with publication bias2 or reporting bias3) where we do not know how many multiple comparisons should be considered. The P value is intended to be an objective measure of the play of chance, and this is (arguably) the case when applied to a pre-specified primary hypothesis in a randomised trial. But this is not the case for cluster investigations, in which the number of multiple comparisons can never be known with any certainty. Statisticians analysing data from a cluster could obtain any P value they wanted by calibrating it against an arbitrary number of multiple comparisons. Where does this leave scientific reasoning in cluster investigations? All cases of cancer have causes; the key question in a cluster investigation is whether the cases have a common cause related to the neighbourhood or workplace from which the cluster was reported. Only rarely is an obvious common cause identified, and a decision to take some action (eg, evacuate the workplace) needs to be based on expert opinion. For the ABC cluster, no obvious common cause was identified. However, the expert panel was concerned that the women with breast cancer were relatively young and were long-term employees at the site, suggesting that there might be an unidentified common cause related to the site.4 This concern, based on expert opinion, is (arguably) enough evidence to evacuate the site. Investigation of cancer clusters is a difficult task. If a common cause cannot be identified, then there is no objective evidence on which to obtain agreement among experts about the importance of the cluster. Specifically, we need to be very clear that, for cluster investigations, a P value (even when adjusted for multiple comparisons) does not provide an objective measure of whether the cluster is due to chance. In the end, an expert group has to make a decision in the presence of uncertainty. When communicating the results to the public, the uncertainty should be acknowledged — as should the fact that experts sometimes disagree.

Michael D Coory