School of Mathematics and Statistics - Research Publications

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    Perceptions of rural high school teachers - on the frontline of youth suicide
    Bowman, S ; McKinstry, C ; Howie, L ; Hepworth, G ; McGorry, P (WILEY, 2022-10)
    OBJECTIVE: This study aimed to investigate the perceptions and beliefs of rural high school teachers about student suicide completion in their school and their perceived self-efficacy in identification of suicidality in students (suicidal ideation, plans and behaviours). DESIGN: A cross-sectional survey methodology. SETTING: Gippsland and the Loddon Mallee regions of Victoria, Australia. PARTICIPANTS: Rural high school teachers. OUTCOME MEASURE: A survey that aimed to obtain participants' perceptions and self-reports about students who had died by suicide in their school within the last 5 years, their perceived self-efficacy in identifying suicidal students and barriers to helping students at risk. RESULTS: Two hundred and seventy-seven rural high school teachers participated and 86% reported that a student from their school had died by suicide within the last 5 years. Sixty-five per cent believed that more than one student had died by suicide and 70% perceived they were currently aware of students experiencing suicidality in their class. Receiving professional development about suicide and obtaining help from mental health clinicians predicted perceived self-efficacy in identification of suicidality in students. Participants perceived the barriers to help students at risk included insufficient numbers of school-based mental health professionals and community mental health services. CONCLUSIONS: Many rural high school teachers perceive they are at the front line of the youth suicide crisis due to unmet service need in youth mental ill health. Increased access to effective services immediately after teachers become aware of suicidality may assist in reducing youth suicide in rural areas.
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    Prevalence of failure of passive immunity transfer in Australian non-replacement dairy calves
    Roadknight, N ; Jongman, E ; Mansell, P ; Courtman, N ; McGill, D ; Hepworth, G ; Fisher, A (WILEY, 2022-07)
    Failure of passive immunity transfer (FPIT) increases the risk of morbidity and mortality in dairy calves. The prevalence of FPIT in dairy calves has generally been reported to be high, with FPIT estimated to occur in 38%-42% of Australian dairy calves. However, the focus of previous studies has been on replacement heifer calves. Our aim was to assess the prevalence of FPIT in Victorian bobby calves (non-replacement dairy calves). We collected blood samples from 3608 bobby calves at three abattoirs at exsanguination, and measured serum total protein as an indicator of passive transfer. We found that 36% of bobby calves showed evidence of FPIT (serum total protein ≤52 g/L), and 50% of calves had poor or fair passive transfer (<58 g/L). When a subset of calves (from farms with more than five calves in the dataset) was analysed using a linear mixed model, Jersey calves and crossbred/other calves had an estimated 5.3 g/L and 5.1 g/L higher serum total protein concentration, respectively, than Holstein-Friesian calves (P < 0.001). Our results suggest that the prevalence of FPIT in bobby calves at abattoirs is similar to that reported in dairy heifer calves sampled on farms. A high prevalence of FPIT has implications for bobby calf morbidity and mortality, as well as calf viability and profitability for dairy-beef production.
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    Does the duration of repeated temporary separation affect welfare in dairy cow-calf contact systems?
    Roadknight, N ; Wales, W ; Jongman, E ; Mansell, P ; Hepworth, G ; Fisher, A (ELSEVIER, 2022-04)
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    Implementing a choice of pulmonary rehabilitation models in chronic obstructive pulmonary disease (HomeBase2 trial): protocol for a cluster randomised controlled trial
    Holland, AE ; Jones, AW ; Mahal, A ; Lannin, NA ; Cox, N ; Hepworth, G ; O'Halloran, P ; McDonald, CF (BMJ PUBLISHING GROUP, 2022-04)
    INTRODUCTION: There is compelling evidence that either centre-based or home-based pulmonary rehabilitation improves clinical outcomes in chronic obstructive pulmonary disease (COPD). There are known health service and personal barriers which prevent potentially eligible patients from accessing the benefits of pulmonary rehabilitation. The aim of this hybrid effectiveness-implementation trial is to examine the effects of offering patients a choice of pulmonary rehabilitation locations (home or centre) compared with offering only the traditional centre-based model. METHOD AND ANALYSIS: This is a two-arm cluster randomised, controlled, assessor-blinded trial of 14 centre-based pulmonary rehabilitation services allocated to intervention (offering choice of home-based or centre-based pulmonary rehabilitation) or control (continuing to offer centre-based pulmonary rehabilitation only), stratified by centre-based programme setting (hospital vs non-hospital). 490 participants with COPD will be recruited. Centre-based pulmonary rehabilitation will be delivered according to best practice guidelines including supervised exercise training for 8 weeks. At intervention sites, the home-based pulmonary rehabilitation will be delivered according to an established 8-week model, comprising of one home visit, unsupervised exercise training and telephone calls that build motivation for exercise participation and facilitate self-management. The primary outcome is all-cause, unplanned hospitalisations in the 12 months following rehabilitation. Secondary outcomes include programme completion rates and measurements of 6-minute walk distance, chronic respiratory questionnaire, EQ-5D-5L, dyspnoea-12, physical activity and sedentary time at the end of rehabilitation and 12 months following rehabilitation.Direct healthcare costs, indirect costs and changes in EQ-5D-5L will be used to evaluate cost-effectiveness. A process evaluation will be undertaken to understand how the choice model is implemented and explore sustainability beyond the clinical trial. ETHICS AND DISSEMINATION: Alfred Hospital Ethics Committee has approved this protocol. The trial findings will be published in peer-reviewed journals, submitted for presentation at conferences and disseminated to patients across Australia with support from national lung charities and societies. TRIAL REGISTRATION NUMBER: NCT04217330.
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    Evaluation of IMproving Palliative care Education and Training Using Simulation in Dementia (IMPETUS-D) a staff simulation training intervention to improve palliative care of people with advanced dementia living in nursing homes: a cluster randomised controlled trial
    Tropea, J ; Nestel, D ; Johnson, C ; Hayes, BJ ; Hutchinson, AF ; Brand, C ; Le, BH ; Blackberry, I ; Caplan, GA ; Bicknell, R ; Hepworth, G ; Lim, WK (BMC, 2022-02-14)
    BACKGROUND: People with dementia have unique palliative and end-of-life needs. However, access to quality palliative and end-of-life care for people with dementia living in nursing homes is often suboptimal. There is a recognised need for nursing home staff training in dementia-specific palliative care to equip them with knowledge and skills to deliver high quality care. OBJECTIVE: The primary aim was to evaluate the effectiveness of a simulation training intervention (IMPETUS-D) aimed at nursing home staff on reducing unplanned transfers to hospital and/or deaths in hospital among residents living with dementia. DESIGN: Cluster randomised controlled trial of nursing homes with process evaluation conducted alongside. SUBJECTS & SETTING: One thousand three hundred four people with dementia living in 24 nursing homes (12 intervention/12 control) in three Australian cities, their families and direct care staff. METHODS: Randomisation was conducted at the level of the nursing home (cluster). The allocation sequence was generated by an independent statistician using a computer-generated allocation sequence. Staff from intervention nursing homes had access to the IMPETUS-D training intervention, and staff from control nursing homes had access to usual training opportunities. The predicted primary outcome measure was a 20% reduction in the proportion of people with dementia who had an unplanned transfer to hospital and/or death in hospital at 6-months follow-up in the intervention nursing homes compared to the control nursing homes. RESULTS: At 6-months follow-up, 128 (21.1%) people with dementia from the intervention group had an unplanned transfer or death in hospital compared to 132 (19.0%) residents from the control group; odds ratio 1.14 (95% CI, 0.82-1.59). There were suboptimal levels of staff participation in the training intervention and several barriers to participation identified. CONCLUSION: This study of a dementia-specific palliative care staff training intervention found no difference in the proportion of residents with dementia who had an unplanned hospital transfer. Implementation of the intervention was challenging and likely did not achieve adequate staff coverage to improve staff practice or resident outcomes. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry (ANZCTR): ACTRN12618002012257 . Registered 14 December 2018.
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    Teaching Radial Endobronchial Ultrasound with a Three-Dimensional-printed Radial Ultrasound Model
    Ridgers, A ; Li, J ; Coles-Black, J ; Jiang, M ; Chen, G ; Chuen, J ; McDonald, CF ; Hepworth, G ; Steinfort, DP ; Irving, LB ; Wallbridge, P ; Jennings, BR ; Phan, N ; Leong, TL (AMER THORACIC SOC, 2021-12)
    BACKGROUND: Peripheral pulmonary lesion (PPL) incidence is rising because of increased chest imaging sensitivity and frequency. For PPLs suspicious for lung cancer, current clinical guidelines recommend tissue diagnosis. Radial endobronchial ultrasound (R-EBUS) is a bronchoscopic technique used for this purpose. It has been observed that diagnostic yield is impacted by the ability to accurately manipulate the radial probe. However, such skills can be acquired, in part, from simulation training. Three-dimensional (3D) printing has been used to produce training simulators for standard bronchoscopy but has not been specifically used to develop similar tools for R-EBUS. OBJECTIVE: We report the development of a novel ultrasound-compatible, anatomically accurate 3D-printed R-EBUS simulator and evaluation of its utility as a training tool. METHODS: Computed tomography images were used to develop 3D-printed airway models with ultrasound-compatible PPLs of "low" and "high" technical difficulty. Twenty-one participants were allocated to two groups matched for prior R-EBUS experience. The intervention group received 15 minutes to pretrain R-EBUS using a 3D-printed model, whereas the nonintervention group did not. Both groups then performed R-EBUS on 3D-printed models and were evaluated using a specifically developed assessment tool. RESULTS: For the "low-difficulty" model, the intervention group achieved a higher score (21.5 ± 2.02) than the nonintervention group (17.1 ± 5.7), reflecting 26% improvement in performance (P = 0.03). For the "high-difficulty" model, the intervention group scored 20.2 ± 4.21 versus 13.3 ± 7.36, corresponding to 52% improvement in performance (P = 0.02). Participants derived benefit from pretraining with the 3D-printed model, regardless of prior experience level. CONCLUSION: 3D-printing can be used to develop simulators for R-EBUS education. Training using these models significantly improves procedural performance and is effective in both novice and experienced trainees.
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    Home-based pulmonary rehabilitation early after hospitalisation in COPD (early HomeBase): protocol for a randomised controlled trial
    Cox, NS ; Lahham, A ; McDonald, CF ; Mahal, A ; O'Halloran, P ; Hepworth, G ; Spencer, L ; McNamara, RJ ; Bondarenko, J ; Macdonald, H ; Gavin, S ; Burge, AT ; Le Maitre, C ; Ringin, C ; Webb, E ; Nichols, A ; Tsai, L-L ; Luxton, N ; van Hilten, S ; Santos, M ; Crute, H ; Byrne, M ; Boursinos, H ; Broe, J ; Corbett, M ; Marceau, T ; Warrick, B ; Boote, C ; Melinz, J ; Holland, AE (BMJ PUBLISHING GROUP, 2021-11)
    INTRODUCTION: Chronic obstructive pulmonary disease (COPD) is characterised by exacerbations of respiratory disease, frequently requiring hospital admission. Pulmonary rehabilitation can reduce the likelihood of future hospitalisation, but programme uptake is poor. This study aims to compare hospital readmission rates, clinical outcomes and costs between people with COPD who undertake a home-based programme of pulmonary rehabilitation commenced early (within 2 weeks) of hospital discharge with usual care. METHODS: A multisite randomised controlled trial, powered for superiority, will be conducted in Australia. Eligible patients admitted to one of the participating sites for an exacerbation of COPD will be invited to participate. Participants will be randomised 1:1. Intervention group participants will undertake an 8-week programme of home-based pulmonary rehabilitation commencing within 2 weeks of hospital discharge. Control group participants will receive usual care and a weekly phone call for attention control. Outcomes will be measured by a blinded assessor at baseline, after the intervention (week 9-10 posthospital discharge), and at 12 months follow-up. The primary outcome is hospital readmission at 12 months follow-up. ETHICS AND DISSEMINATION: Human Research Ethics approval for all sites provided by Alfred Health (Project 51216). Findings will be published in peer-reviewed journals, conferences and lay publications. TRIAL REGISTRATION NUMBER: ACTRN12619001122145.
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    Bias correction of estimated proportions using inverse binomial group testing
    Hepworth, G (WILEY, 2019-03)
    Summary Group testing, in which individuals are pooled together and tested as a group, can be combined with inverse sampling to estimate the prevalence of a disease. Alternatives to the MLE are desirable because of its severe bias. We propose an estimator based on the bias correction method of Firth (1993), which is almost unbiased across the range of prevalences consistent with the group testing design. For equal group sizes, this estimator is shown to be equivalent to that derived by applying the correction method of Burrows (1987), and better than existing methods. For unequal group sizes, the problem has some intractable elements, but under some circumstances our proposed estimator can be found, and we show it to be almost unbiased. Calculation of the bias requires computer‐intensive approximation because of the infinite number of possible outcomes.
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    Mid-P confidence intervals for group testing based on the total number of positive groups
    Hepworth, G ; Katholi, CR (WILEY, 2019-05)
    In the estimation of proportions by group testing, unequal sized groups results in an ambiguous ordering of the sample space, which complicates the construction of exact confidence intervals. The total number of positive groups is shown to be a suitable statistic for ordering outcomes, provided its ties are broken by the MLE. We propose an interval estimation method based on this quantity, with a mid-P correction. Coverage is evaluated using group testing problems in plant disease assessment and virus transmission by insect vectors. The proposed method provides good coverage in a range of situations, and compares favorably with existing exact methods.
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    Randomised controlled trial of the effect of concentration of progesterone before artificial insemination on fertility in ovulatory and anovulatory Bos indicus cattle
    Cavalieri, J ; Gaina, C ; Hepworth, G (WILEY, 2018-09)
    OBJECTIVE: To investigate the effect of concentration of progesterone (P4) before artificial insemination (AI) on fertility in ovulatory or anovulatory Bos indicus cattle. DESIGN: Randomised control study METHODS: The study included 162 heifers and 96 lactating cows. On days -10 to -12, animals were examined using transrectal ultrasound, administered PG and examined for a corpus luteum (CL). Those with a CL were allocated to Experiment 1. On day 0 they were administered an intravaginal progesterone-releasing device (IVD) containing progesterone (P4) (0.78 g), oestrodiol benzoate (ODB) and either saline or PG to induce high and low circulating P4 concentrations, respectively. Those without a CL were re-examined on day 0 and those without a CL at both examinations were allocated to Experiment 2. Cows and heifers were treated with an IVD containing P4 at 0.78 g or 1.56 g to induce low or high P4 concentrations, respectively. IVDs were removed on day 7 and PG and equine chorionic gonadotrophin (eCG) were administered. Females in oestrus on day 9 were inseminated; others were administered ODB and inseminated 22-26 h later. RESULTS: Greater concentrations of circulating P4 increased the odds of pregnancy to AI in anovulatory females (P = 0.008), but decreased the odds of pregnancy in one year but not another in ovulatory animals (P × year, P = 0.019). CONCLUSION: Manipulating P4 concentrations before AI has the potential to improve pregnancy outcomes to AI in B. indicus females, but treatment may need to vary between animals classified as anovulatory or ovulatory.