Exploring the use of masks for protection against the effects of wildfire smoke among people with preexisting respiratory conditions

BACKGROUND

The impact of wildfire smoke is a growing public health issue, especially for those living with preexisting respiratory conditions. Understanding perceptions and behaviors relevant to the use of individual protective strategies, and how these affect the adoption of these strategies, is critical for the development of future communication and support interventions. This study focused on the use of masks by people living in the Australian community with asthma or chronic obstructive pulmonary disease (COPD).

METHODS

Semi-structured phone interviews were undertaken with people living in the community aged 18 years and over. Participants lived in a bushfire-prone area and reported having been diagnosed with asthma or COPD.

RESULTS

Twenty interviews were undertaken between July and September 2021. We found that, during wildfire episodes, there was an overwhelming reliance on closing windows and staying inside as a means of mitigating exposure to smoke. There was limited use of masks for this purpose. Even among those who had worn a mask, there was little consideration given to the type of mask or respirator used. Reliance on sensory experiences with smoke was a common prompt to adopting an avoidance behavior. Participants lacked confidence in the information available from air-quality apps and websites, however they were receptive to the idea of using masks in the future.

CONCLUSIONS

Whilst COVID-19 has changed the nature of community mask use over the last couple of years, there is no guarantee that this event will influence an individual's mask behavior during other events like bushfires. Instead, we must create social support processes for early and appropriate mask use, including the use of air quality monitoring.

Enhanced EPIRISK tool for rapid epidemic risk analysis

OBJECTIVES

This study aims to create an enhanced EPIRISK tool in order to correctly predict COVID-19 severity in various countries. The original EPIRISK tool was developed in 2018 to predict the epidemic risk and prioritise response. The tool was validated against nine historical outbreaks prior to 2020. However, it rated many high-income countries that had poor performance during the COVID-19 pandemic as having lower epidemic risk.

STUDY DESIGN

This study was designed to modify EPIRISK by reparameterizing risk factors and validate the enhanced tool against different outbreaks, including COVID-19.

METHODS

We identified three factors that could be indicators of poor performance witnessed in some high-income countries: leadership, culture and universal health coverage. By adding these parameters to EPIRISK, we created a series of models for the calibration and validation. These were tested against non-COVID outbreaks in nine countries and COVID-19 outbreaks in seven countries to identify the best-fit model. The COVID-19 severity was determined by the global incidence and mortality, which were equally divided into four levels.

RESULTS

The enhanced EPIRISK tool has 17 parameters, including seven disease-related and 10 country-related factors, with an algorithm developed for risk level classification. It correctly predicted the risk levels of COVID-19 for all seven countries and all nine historical outbreaks.

CONCLUSIONS

The enhanced EPIRSIK is a multifactorial tool that can be widely used in global infectious disease outbreaks for rapid epidemic risk analysis, assisting first responders, government and public health professionals with early epidemic preparedness and prioritising response to infectious disease outbreaks.

Could it be monkeypox? Use of an AI-based epidemic early warning system to monitor rash and fever illness

OBJECTIVES

The EPIWATCH artificial intelligence (AI) system scans open-source data using automated technology and can be used to detect early warnings of infectious disease outbreaks. In May 2022, a multicountry outbreak of Mpox in non-endemic countries was confirmed by the World Health Organization. This study aimed to identify signals of fever and rash-like illness using EPIWATCH and, if detected, determine if they represented potential Mpox outbreaks.

STUDY DESIGN

The EPIWATCH AI system was used to detect global signals for syndromes of rash and fever that may have represented a missed diagnosis of Mpox from 1 month prior to the initial case confirmation in the United Kingdom (7 May 2022) to 2 months following.

METHODS

Articles were extracted from EPIWATCH and underwent review. A descriptive epidemiologic analysis was conducted to identify reports pertaining to each rash-like illness, locations of each outbreak and report publication dates for the entries from 2022, with 2021 as a control surveillance period.

RESULTS

Reports of rash-like illnesses in 2022 between 1 April and 11 July (n = 656 reports) were higher than in the same period in 2021 (n = 75 reports). The data showed an increase in reports from July 2021 to July 2022, and the Mann-Kendall trend test showed a significant upward trend (P = 0.015). The most frequently reported illness was hand-foot-and-mouth disease, and the country with the most reports was India.

CONCLUSIONS

Vast open-source data can be parsed using AI in systems such as EPIWATCH to assist in the early detection of disease outbreaks and monitor global trends.

Pneumonia hospitalisation and case-fatality rates in older Australians with and without risk factors for pneumococcal disease: implications for vaccine policy

Community-acquired pneumonia (CAP) results in substantial numbers of hospitalisations and deaths in older adults. There are known lifestyle and medical risk factors for pneumococcal disease but the magnitude of the additional risk is not well quantified in Australia. We used a large population-based prospective cohort study of older adults in the state of New South Wales (45 and Up Study) linked to cause-specific hospitalisations, disease notifications and death registrations from 2006 to 2015. We estimated the age-specific incidence of CAP hospitalisation (ICD-10 J12-18), invasive pneumococcal disease (IPD) notification and presumptive non-invasive pneumococcal CAP hospitalisation (J13 + J18.1, excluding IPD), comparing those with at least one risk factor to those with no risk factors. The hospitalised case-fatality rate (CFR) included deaths in a 30-day window after hospitalisation. Among 266 951 participants followed for 1 850 000 person-years there were 8747 first hospitalisations for CAP, 157 IPD notifications and 305 non-invasive pneumococcal CAP hospitalisations. In persons 65-84 years, 54.7% had at least one identified risk factor, increasing to 57.0% in those ⩾85 years. The incidence of CAP hospitalisation in those ⩾65 years with at least one risk factor was twofold higher than in those without risk factors, 1091/100 000 (95% confidence interval (CI) 1060-1122) compared with 522/100 000 (95% CI 501-545) and IPD in equivalent groups was almost threefold higher (18.40/100 000 (95% CI 14.61-22.87) vs. 6.82/100 000 (95% CI 4.56-9.79)). The CFR increased with age but there were limited difference by risk status, except in those aged 45 to 64 years. Adults ⩾65 years with at least one risk factor have much higher rates of CAP and IPD suggesting that additional risk factor-based vaccination strategies may be cost-effective.

Retrospective cost-effectiveness of the 23-valent pneumococcal polysaccharide vaccination program in Australia

BACKGROUND

The Australian infant pneumococcal vaccination program was funded in 2005 using the 7-valent pneumococcal conjugate vaccine (PCV7) and the 13-valent conjugate vaccine (PCV13) in 2011. The PCV7 and PCV13 programs resulted in herd immunity effects across all age-groups, including older adults. Coincident with the introduction of the PCV7 program in 2005, 23-valent pneumococcal polysaccharide vaccine (PPV23) was funded for all Australian adults aged over 65 years.

METHODS

A multi-cohort Markov model with a cycle length of one year was developed to retrospectively evaluate the cost-effectiveness of the PPV23 immunisation program from 2005 to 2015. The analysis was performed from the healthcare system perspective with costs and quality-adjusted life years discounted at 5% annually. The incremental cost-effectiveness ratio (ICER) for PPV23 doses provided from 2005 to 2015 was calculated separately for each year when compared to no vaccination. Parameter uncertainty was explored using deterministic and probabilistic sensitivity analysis.

RESULTS

It was estimated that PPV23 doses given out over the 11-year period from 2005 to 2015 prevented 771 hospitalisations and 99 deaths from invasive pneumococcal disease (IPD). However, the estimated IPD cases and deaths prevented by PPV23 declined by more than 50% over this period (e.g. from 12.9 deaths for doses given out in 2005 to 6.1 in 2015), likely driven by herd effects from infant PCV programs. The estimated ICER over the period 2005 to 2015 was approximately A$224,000/QALY gained compared to no vaccination. When examined per year, the ICER for each individual year worsened from $140,000/QALY in 2005 to $238,000/QALY in 2011 to $286,000/QALY in 2015.

CONCLUSION

The cost-effectiveness of the PPV23 program in older Australians was estimated to have worsened over time. It is unlikely to have been cost-effective, unless PPV23 provided protection against non-invasive pneumococcal pneumonia and/or a low vaccine price was negotiated. A key policy priority should be to review of the future use of PPV23 in Australia, which is likely to be more cost-effective in certain high-risk groups.

Phylogeography of H5N1 avian influenza virus in Indonesia

Highly pathogenic avian influenza (HPAI) viruses of the H5N1 subtype are a major concern to human and animal health in Indonesia. This study aimed to characterize transmission dynamics of H5N1 over time using novel Bayesian phylogeography methods to identify factors which have influenced the spread of H5N1 in Indonesia. We used publicly available hemagglutinin sequence data sampled between 2003 and 2016 to model ancestral state reconstruction of HPAI H5N1 evolution. We found strong support for H5N1 transmission routes between provinces in Java Island and inter-island transmissions, such as between Nusa Tenggara and Kalimantan Islands, not previously described. The spread is consistent with wild bird flyways and poultry trading routes. H5N1 migration was associated with the regions of high chicken densities and low human development indices. These results can be used to inform more targeted planning of H5N1 control and prevention activities in Indonesia.

The role of timeliness in the cost-effectiveness of older adult vaccination: A case study of pneumococcal conjugate vaccine in Australia

While the impact of the timeliness of vaccine administration has been well-studied for childhood vaccinations, there has been little detailed quantitative analysis on the potential impact of the timeliness of vaccinations in older adults. The aim of this study was to explore the impact of implementing more realistic observed uptake distributions, taking into the account reduced vaccine efficacy but higher pneumococcal disease burden with increasing age beyond 65 years. A multi-cohort Markov model was constructed to evaluate the cost-effectiveness of a pneumococcal (PCV13) immunisation program in Australia, assuming two different uptake modelling approaches. The approach using an estimate of observed uptake was compared with a scenario in which the total cumulative uptake was delivered at the recommended age of vaccination. We found these two approaches produced different results both in terms of cases prevented and cost-effectiveness. The impact of the non-timely uptake in adult programs may sometimes have positive and other times negative effects, depending on several factors including the age-specific disease rates and the duration of vaccine protection. Our study highlights the importance of using realistic assumptions around uptake (including non-timely vaccination) when estimating the impact of vaccination in adults.

Cost-effectiveness of 13-valent pneumococcal conjugate vaccine (PCV13) in older Australians

BACKGROUND

The 23-valent pneumococcal polysaccharide vaccine (PPV23) has been funded under the Australia National Immunisation Program (NIP) since January 2005 for those aged >65years and other risk groups. In 2016, PCV13 was accepted by the Pharmaceutical Benefits Advisory Committee (PBAC) as a replacement for a single dose of PPV23 in older Australian adults.

METHODS

A single-cohort deterministic multi-compartment (Markov) model was developed describing the transition of the population between different invasive and non-invasive pneumococcal disease related health states. We applied a healthcare system perspective with costs (Australian dollars, A$) and health effects (measured in quality adjusted life-years, QALYs) attached to model states and discounted at 5% annually. We explored replacement of PPV23 with PCV13 at 65years as well as other age based vaccination strategies. Parameter uncertainty was explored using deterministic and probabilistic sensitivity analysis.

RESULTS

In a single cohort, we estimated PCV13 vaccination at the age of 65years to cost ∼A$11,120,000 and prevent 39 hospitalisations and 6 deaths from invasive pneumococcal disease and 180 hospitalisations and 10 deaths from community acquired pneumonia. The PCV13 program had an incremental cost-effectiveness ratio of ∼A$88,100 per QALY gained when compared to a no-vaccination, whereas PPV23 was ∼A$297,200 per QALY gained. To fall under a cost-effectiveness threshold of A$60,000 per QALY, PCV13 would have to be priced below ∼A$46 per dose. The cost-effectiveness of PCV13 in comparison to PPV23 was ∼A$35,300 per QALY gained.

CONCLUSION

In comparison to no-vaccination, we found PCV13 use in those aged 65years was unlikely to be cost-effective unless the vaccine price was below A$46 or a longer duration of protection can be established. However, we found that in comparison to the PPV23, vaccination with PCV13 was cost-effective. This partly reflects the poor value for money estimated for PPV23 use in Australia.

A review of economic evaluations of 13-valent pneumococcal conjugate vaccine (PCV13) in adults and the elderly

The 13-valent pneumococcal conjugated vaccine (PCV13) is already recommended for some adult groups and is being considered for wider use in many countries. In order to identify the strengths and limitations of the existing economic evaluation studies of PCV13 in adults and the elderly a literature review was conducted. The majority of the studies identified (9 out of 10) found that PCV13 was cost-effective in adults and/or the elderly. However, these results were based on assumptions that could not always be informed by robust evidence. Key uncertainties included the efficacy of PCV13 against non-invasive pneumonia and the herd immunity effect of childhood vaccination programs. Emerging trial evidence on PCV13 in adults from the Netherlands offers the ability to parameterize future economic evaluations with empirical efficacy data. However, it is important that these estimates are used thoughtfully when they are transferred to other settings.

Treatment outcomes of various types of tuberculosis in Pakistan, 2006 and 2007

Measuring treatment outcome is important for successful tuberculosis (TB) control programmes. The purpose of this study was to examine the outcomes of various types of TB cases registered in Pakistan over a 2-year period and compare those outcomes among the different provinces and regions of the country. A retrospective, cohort study was conducted in which TB treatment outcome reports were reviewed. Of the 349 694 pulmonary TB cases registered in Pakistan during 2006 and 2007, 309154 (88.4%) were treated successfully. Treatment success was significantly higher in new smear-positive cases and lower in retreatment cases. Among the provinces and regions, treatment success was significantly higher in 4 out of 8 provinces. Treatment success needs to be improved, particularly in retreatment cases. The national TB control programme should review the provincial and regional programmes and learn lessons from well-performing programmes. Patient factors that may affect the treatment outcome should be also studied.

Prevention and surveillance of public health risks during extended mass gatherings in rural areas: the experience of the Tamworth Country Music Festival, Australia

OBJECTIVE

To describe and evaluate the public health response to the Tamworth Country Music Festival, an annual extended mass gathering in rural New South Wales, Australia; and to propose a framework for responding to similar rural mass gatherings.

STUDY DESIGN

Process evaluation by direct observation, archival analysis and focus group discussion.

METHODS

The various components of the public health response to the 2011 Tamworth Country Music Festival were actively recorded. An archival review of documentation from 2007 to 2010 was performed to provide context. A focus group was also conducted to discuss the evolution of the public health response and the consequences of public health involvement.

RESULTS

Public health risks increased with increasing duration of the rural mass gathering. Major events held within the rural mass gathering further strained resources. The prevention, preparedness, response and recovery principles provided a useful framework for public health actions. Particular risks included inadequately trained food preparation volunteers functioning in poorly equipped temporary facilities, heat-related ailments and arboviral disease.

CONCLUSION

Extended mass gatherings in rural areas pose particular public health challenges; surge capacity is limited and local infrastructure may be overwhelmed in the event of an acute incident or outbreak. There is value in proactive public health surveillance and monitoring. Annual mass gatherings provide opportunities for continual systems improvement. Early multi-agency planning can identify key risks and identify opportunities for partnership. Special consideration is required for major events within mass gatherings.

Acceptance of a vaccine against pandemic influenza A (H1N1) virus amongst healthcare workers in Beijing, China

Due to the advent of the new influenza A (H1N1) strain in 2009, many countries introduced mass immunization programs. Healthcare workers (HCWs) were amongst the key groups targeted for the vaccine in these programs. However, experience with the seasonal influenza vaccine has shown that there are multiple barriers related to the attitudes and perceptions of the population which influence uptake. The aim of this study was to determine pandemic influenza A (H1N1) vaccination rate amongst a group of Chinese HCWs and the associated factors around acceptance. A cross-sectional investigation of HCWs (doctors, nurses and technicians) from 19 hospitals in Beijing, China was conducted in January 2010. The main outcome measures were awareness, risk perception of H1N1, preventive measures and uptake of H1N1 vaccination during the pandemic. A total of 1657 HCWs completed the survey. A quarter of the participants reported receiving the pandemic influenza A (H1N1) vaccine. Occupation (being a doctor), receiving seasonal flu vaccine and believing in the effectiveness of the vaccine were all strongly associated with accepting the pandemic influenza A (H1N1) vaccine. Over a thousand participants (61%, 1008/1657) agreed that they were 'concerned about the side effects of the swine flu vaccine', while 758 (46%) were 'concerned that the vaccine had not been tested adequately'. While studies reported high rates of willingness to receive the vaccine, in reality these did not transpire. Aside from promoting seasonal flu vaccination, authorities need to start educational campaigns much earlier in a pandemic. Programs that are simultaneously launched with the introduction of the vaccine will not be as successful, as those which have built momentum alongside the pandemic.

Difficulties in recruiting older people in clinical trials: an examination of barriers and solutions

Limited information exists regarding optimal methods for the recruitment and retention of older people in clinical trials. The aim of this review is to identify common barriers to the recruitment of older people in clinical trials and to propose solutions to overcome these barriers. A review of literature was performed to identify common difficulties in recruiting older people. This in combination with our experience during recruitment for a randomized control trial, have highlighted numerous barriers. Population-specific recruitment strategies, simple informed-consent processes, and effective communication between the researcher and subject are effective strategies to overcome these barriers.

Population-based seroprevalence of Neisseria meningitidis serogroup C capsular antibody before the introduction of conjugate vaccine, in Australia

Neisseria meningitidis serogroup C (NMC) conjugate vaccine was introduced, in Australia, in 2003. Our aims were to determine pre-immunisation IgG NMC seroprevalence and evaluate an enzyme-linked immunosorbent assay (ELISA), previously validated against the serum bactericidal assay (SBA). 2409 sera, collected in 2002, from subjects aged 2-34 years, were tested. The geometric mean concentration (GMC) of NMC anticapsular IgG was 0.38 U/mL in subjects under 19 years and it increased to 0.67 U/mL for those aged 30-34 years. Variation in GMC correlated with reported NMC disease incidence and was higher in males than females (0.52 U/mL versus 0.41 U/mL; p=0.005). The ELISA appears suitable for serosurveillance but the IgG level that correlates with protection needs further investigation. Serosurveys will be repeated to monitor the impact of vaccination.

Childhood asthma diagnosis and use of asthma medication

AIM

To determine the burden of asthma in children.

METHODS

A cross sectional, randomised, computer assisted telephone survey of a community based sample of 2020 children aged 5-14 years in western Sydney (New South Wales) over a 20 day period from June 2000 to July 2000.

RESULTS

Main outcome measures were carer reported history of asthma diagnosis, hospital presentation/admission for asthma, recent use of anti-asthma medications, and recent respiratory symptoms. Diagnosed asthma was reported in 31% (of whom 42% were diagnosed aged 2 years or under) and asthma medications used in the previous year by 21% of children. Factors significantly associated with a reported asthma diagnosis included: male gender (OR: 1.51), birth in Australia (OR: 1.64), living in an English speaking household (OR: 1.47), Aboriginality (OR: 2.32), possession of a health care card (OR: 1.28), previous pneumonia (OR: 2.4) or pertussis (OR: 2.0), and a recent episode of croup (OR: 1.9). Exposure to tobacco smoke and immunisation status were not significant.

DISCUSSION

We confirm a high prevalence of asthma and medication use for asthma. The high proportion of children diagnosed asthmatic at 2 years or under (when asthma cannot be diagnosed reliably) suggests overdiagnosis of asthma may contribute to the apparent high prevalence.

Community-based estimates of incidence and risk factors for childhood pneumonia in Western Sydney

The aim was to estimate the community incidence and risk factors for all-cause pneumonia in children in Western Sydney, Australia. A cross-sectional randomized computer-assisted telephone interview was conducted in July 2000, in Western Sydney. Parents of 2020 children aged between 5 and 14 years were interviewed about their child's respiratory health since birth. No verification of reported diagnosis was available. Logistic regression analysis was used to determine risk factors for pneumonia. A lifetime diagnosis of pneumonia was reported in 137/2020 (68%) children, giving an estimated incidence in the study sample of 7.6/1000 person-years. Radiological confirmation was reported in 85% (117/137). Hospitalization was reported in 41% (56/137) and antibiotic therapy in 93% (127/137) of cases. Using logistic regression modelling, statistically significant associations with pneumonia were a reported history of either asthma, bronchitis or other lung problems and health problems affecting other systems. In most cases, the diagnosis of asthma preceded the diagnosis of pneumonia. The community incidence of all causes of pneumonia is not well enumerated, either in adults or in children. This study provides community-based incidence data. The incidence of hospitalization for pneumonia in this study is comparable to estimates from studies in comparable populations, suggesting that retrospective parental report for memorable events is likely to be valid. We found a relationship between pneumonia and childhood respiratory diseases such as asthma, which has implications for targeted vaccination strategies.

The seroepidemiology and transmission dynamics of varicella in Australia

To enhance our understanding of the epidemiology and transmission dynamics of varicella in the pre-vaccine era we performed a serosurvey using opportunistically collected sera submitted to diagnostic laboratories across Australia during 1997-1999. A representative sample by state and sex of 2027 sera from persons aged 1-49 years was tested using an enzyme immunoassay method. The average age of infection and age-specific forces of infection (the probability that a susceptible individual acquires infection) were calculated using published methodologies. Seropositivity increased with age, with 83% of sera positive by ages 10-14 years. The highest force of infection was in the 5-9 years age group (0.195 per susceptible year) followed by the 0-4 years age group (0.139 per susceptible year) and the average age of infection was 8.15 years. These results provide valuable baseline information to measure the impact of vaccination and indicate that vaccination should be aimed at children less than 5 years of age, although further modelling using the serosurvey data is warranted.

Immunization myths and realities: responding to arguments against immunization

As vaccination programs continue to successfully control more and more infectious diseases, and the effects of these diseases become less visible, there has been increased focus on adverse events following immunization. Vaccines have been falsely implicated in the causation of a range of conditions, especially those which affect infants and young children, and whose aetiology is unknown, poorly understood or multifactorial. This paper explores some of the common immunization myths that clinicians may face. It is essential that health professionals have access to accurate information and are able to respond appropriately to parental concerns. This involves good communication; listening, empathy and tailoring advice to the specific concerns of the parent. Finally, health professionals need to provide consistent messages based on solid research evidence.

A randomised controlled clinical trial of the efficacy of family-based direct observation of anti-tuberculosis treatment in an urban, developed-country setting

SETTING

A randomised, controlled clinical trial of the effectiveness of a family-based programme of directly observed treatment (DOT) for tuberculosis.

METHODS

TB patients seen in Victoria, Australia, were randomly allocated to DOT observed by a family member (FDOT), or to standard supervised but non-observed therapy (ST). The outcome measure was compliance, measured by blinded testing of isoniazid levels in urine. An intention-to-treat analysis was used.

RESULTS

Of 173 patients, 87 were allocated to FDOT and 86 to ST. Only 58% in the FDOT group were able to receive FDOT, the major reason being living alone and not having a family member to observe treatment. The rate of non-compliance was 24% (41/173), with no significant difference between FDOT (22/87) and ST (19/86). No clinical or socio-demographic variable predicted compliance.

CONCLUSIONS

We were unable to demonstrate a benefit of FDOT in an urban, industrialised country setting. FDOT may be more appropriate in developing countries, where extended family support is often available and the burden of TB is much higher. Poor compliance and the difficulty in predicting non-compliance shown in this study highlights the need for DOT for all TB patients.

Use of hospitalization and pharmaceutical prescribing data to compare the prevaccination burden of varicella and herpes zoster in Australia

The aims of the study were to compare the burden of varicella and herpes zoster in Australia. No national surveillance exists for varicella or herpes zoster. We used hospital morbidity data from 1993-9 and pharmaceutical prescribing data from 1995-9. In the financial year 1998/99, there were 4718 hospitalizations for zoster compared to 1991 for varicella. For varicella the mean age of patients was 15 years compared to 69 years for zoster. The mean length of stay in hospital was 4.2 days for varicella and 12.7 days for zoster. Varicella accounted for 8396 (3726 with principal diagnosis varicella) bed days compared to 26 266 (5382 with principal diagnosis of zoster) for zoster. The in-hospital case-fatality rate was 0.4% for varicella and 1% for zoster. In 1999, 59 200 community-based cases of zoster were treated with antivirals. We estimate that 157 266 cases of zoster occurred in the community in 1999, a rate of 830 per 100 000 population. Herpes zoster has a higher burden of disease than varicella, and must be a component of disease surveillance in order to determine the full impact of vaccination on the epidemiology of varicella zoster virus (VZV).

Hepatitis A vaccination options for Australia

The epidemiology of hepatitis A is changing, with an increasing proportion of the population becoming susceptible to infection. The burden of hepatitis A is comparable to that of other vaccine-preventable diseases for which new vaccines are available. Options for vaccination include selective programmes for high-risk groups, which could involve screening prior to vaccination, or universal programmes for infants and/or adolescents. Selective programmes have been shown to be highly cost-effective if well implemented, but there is evidence that they might be poorly implemented. If a universal vaccination programme were considered for Australia, an infant programme, with doses at 18 months and 2 years, possibly with an additional adolescent programme, would be the recommended option. Universal hepatitis A vaccination for infants and/or adolescents is of comparable cost-effectiveness compared with other preventive strategies, but needs to be considered in the context of competing vaccination options.

A randomised, clinical trial comparing the effectiveness of hospital and community-based reminder systems for increasing uptake of influenza and pneumococcal vaccine in hospitalised patients aged 65 years and over

Hospitalisation represents an opportunity to identify unimmunised people at risk for the complications of influenza and pneumococcal disease. We conducted a randomised controlled trial of two strategies to increase uptake of influenza and pneumococcal vaccines in eligible, hospitalised subjects aged 65 years or more, admitted between May and September 1998 to a Melbourne hospital. Unvaccinated participants were allocated randomly to alert systems for hospital staff or community general practitioners (GPs). Follow-up occurred at 1 and 3 months. The baseline vaccination rates were 70% for influenza (426/606) and 41% (248/606) for pneumococcal disease. For unvaccinated subjects, the hospital alert resulted in 67% uptake compared to 55% following a GP alert for pneumococcal vaccine; and 63% in hospital compared to 53% following a GP alert for influenza vaccine. Although there was a trend toward a higher uptake in hospital, neither of these differences was statistically significant. The majority (75%) of vaccinations following a GP alert occurred within 1 month of discharge. Despite hospital and community-based reminder systems, there are still significant missed opportunities for vaccination. We did not demonstrate significant differences between hospital and GP reminder systems, but there was a trend towards higher uptake with opportunistic vaccination in hospital.

A mathematical model to measure the impact of the Measles Control Campaign on the potential for measles transmission in Australia

BACKGROUND

The aims of this study were to determine the impact of the Australian Measles Control Campaign (MCC) on the transmission dynamics of measles by calculating the reproductive number (R) before and after the MCC, and to predict measles control in Australia in the future.

METHODS

A national serosurvey was conducted before and after the MCC. Sera were tested for anti-measles IgG using enzyme immunoassay (EIA). A mathematical model, using serosurvey results and vaccine coverage estimates, was used to calculate the change in R after the MCC.

RESULTS

The values of R calculated before and after the MCC were 0.90 and 0.57. At vaccine coverage levels indicated by the Australian Childhood Immunisation Register (ACIR), the value of R will exceed 1 (the epidemic threshold) in 2007-2008 nationally, and sooner in some regions of Australia. Coverage of at least 84% with two doses of MMR is required to sustain measles control.

CONCLUSIONS

The Australian MCC had a significant impact on the transmission dynamics of measles. However, current vaccine coverage levels may result in indigenous measles transmission by 2007. Sustained efforts are required to improve coverage with two doses of MMR and to ensure elimination of indigenous measles transmission.

Seasonality of coronary artery deaths in New South Wales, Australia

BACKGROUND

Complex temporal variations in coronary deaths, including diurnal, weekly, and seasonal trends, have been reported worldwide.

OBJECTIVE

To describe the magnitude of seasonal changes in coronary artery deaths in New South Wales, Australia.

DESIGN

Hospital morbidity data, mortality statistics, and meteorological data were modelled using time series techniques to determine seasonality of coronary deaths. Data were also analysed to determine whether there was an increase in deaths before or after the Christmas and New Year holidays.

RESULTS

A clear seasonality of coronary deaths was shown, with a peak in July. A mean of 2.8 excess coronary deaths per 100 deaths was estimated to occur from June to August each year, with a mean annual excess of 224 winter deaths a year. Mortality data did not show an increase in coronary death ratios before (p = 0.626) or after (p = 0.813) the Christmas and New Year holidays in December.

CONCLUSIONS

There is a higher incidence of coronary deaths in winter, which may reflect winter respiratory infections, the direct effect of cold, seasonal changes in lipid concentration, and other factors associated with winter. Hospitals should have contingency plans during the winter months to manage larger numbers of cardiac admissions.

Chronic Strongyloides stercoralis infection in Laotian immigrants and refugees 7-20 years after resettlement in Australia

During the period 1974-91 large numbers of Southeast Asian immigrants and refugees were resettled in Western countries, including Australia. Health screening during this period demonstrated that intestinal parasite infections were common. A cross-sectional survey of 95 Laotian settlers who arrived in Australia on average 12 years prior to the study was conducted to determine if chronic intestinal parasite infections were prevalent in this group. Twenty-three participants had positive Strongyloides stercoralis test results (22 with positive serology, including I with S. stercoralis larvae detected in faeces and another with larvae and equivocal serology). Of these 23 participants, 18 (78%) had an elevated eosinophil count. Two patients had eggs of Opisthorchis spp. identified by faecal microscopy. The detection of chronic strongyloidiasis in Laotian settlers is a concern because of the potential serious morbidity associated with this pathogen.

School immunisation certificates--a review over time in a disadvantaged community

OBJECTIVES

To compare proportions of kindergarten children in Auburn presenting School Immunisation Certificates (SIC) or other school-entry immunisation documentation over time, and to examine the immunisation status of these children.

METHODS

Immunisation records of kindergarten children enrolled in all primary schools in the Auburn local government area were reviewed in 1994 and 1998.

RESULTS

Eight hundred and thirty-three and 737 school entry records of children enrolled in kindergarten were reviewed in 1998 and 1994 respectively. There was no change in the overall proportion of children with immunisation documentation and SICs. Sixty-nine per cent (571/833) of children had SICs in 1998, compared with 72% (531/737) in 1994. Thirteen per cent of children had other immunisation documentation in 1998, compared with 11% in 1994. The proportion of invalid certificates fell from 39.2% in 1994 to 12.6% in 1998 (p<0.001). The 1998 survey indicated that 80.2% of children provided a certificate indicating they were completely immunised compared with 56.7% in 1994 (p<0.001).

IMPLICATIONS

Although SICs play an important role in promoting the importance of immunisation among parents and in the school community, there continues to be a substantial number of children whose immunisation status is unknown. In the event of an outbreak, an effective public health response may need to incorporate the use of additional objective measures, such as the Australian Childhood Immunisation Register or personal health records.

Risk factors for colonization with vancomycin-resistant enterococci in a Melbourne hospital

OBJECTIVE

To determine risk factors for colonization with vancomycin-resistant enterococci (VRE) in a hospital outbreak.

DESIGN

Outbreak investigation and case-control study.

SETTING

A referral teaching hospital in Melbourne, Australia.

PARTICIPANTS

Cases were inpatients colonized (with or without clinical disease) with VRE between July 26 and November 28, 1998; controls were hospitalized patients without VRE.

METHODS

Five cases of VRE were identified between July 26 and November 8, 1998, by growth of VRE from various sites. Active case finding by cultures of rectal swabs from patients surveyed in wards was commenced on July 26, after the first isolate of VRE.

RESULTS

There were 19 cases and 66 controls. All the VRE identified were vanB, and all were Enterococcus faecium. One molecular type predominated (18/19 cases). In a logistic-regression model, being on the same ward as a VRE case was the highest risk factor (odds ratio [OR], 82; 95% confidence interval [CI95], 5.7-1,176; P=.001). Having more than five antibiotics (OR, 11.9; CI95 1.1-129.6; P<.05), use of metronidazole (OR, 10.9; CI95, 1.7-69.8; P=.01), and being a medical patient (OR, 8.1; CI95, 1.4-47.6; P<.05) also were significant. Intensive care unit admission was associated with decreased risk (OR, 0.1; CI95, 0.01-0.8; P<.05).

CONCLUSION

Our findings are consistent with an acute hospital outbreak. Monitoring and control of antibiotic use, particularly metronidazole, may reduce VRE in our hospital. Ongoing surveillance and staff education also are necessary.

Hepatitis B vaccine: risks and benefits of universal neonatal vaccination

Global eradication of hepatitis B, which has infected over 2000 million people worldwide, is an achievable goal. Hepatitis B vaccine is effective and safe, and is recommended in Australia as a four-dose childhood schedule commencing with a neonatal dose. A neonatal dose has a greater impact on carriage, the main reservoir of transmission, due to the inverse relationship of age and risk of chronic carriage. Universal vaccination is clearly cost-effective in countries of high hepatitis B endemicity but less so in countries of low endemicity. Other factors affecting the perceived benefits of universal vaccination in low-risk countries include the use of the preservative thiomersal in hepatitis B vaccines, and case reports of multiple sclerosis (MS) and unexplained fever in recipients. Careful epidemiological studies have failed to confirm any risk of MS or fever with the hepatitis B vaccine, which is now thiomersal-free. Other arguments against universal vaccination include 'unnecessary' vaccination of low-risk neonates. However, selective vaccination programmes targeting at-risk neonates are often poorly implemented and do not protect against horizontal transmission in early childhood. Universal vaccination, which is safe and effective, is the only practical means of achieving global eradication of hepatitis B.

Shifting the balance between in-patient and out-patient care for tuberculosis results in economic savings

SETTING

Although hospitalisation is not always necessary for the treatment of tuberculosis (TB), in Australia 90% of TB patients have treatment initiated in hospital.

OBJECTIVE

To calculate and compare the costs of in-patient and out-patient tuberculosis treatment, and to measure the impact of shifting care from in-patient to out-patient settings.

METHODS

In a costing study performed in Victoria, Australia, the proportion of all notified TB cases who were hospitalised was calculated by matching coded state hospital morbidity data with the Victoria Notifiable Diseases database for the financial year 1994-1995. In-patient and out-patient costs were calculated using data obtained from a number of sources. The effect on health care costs of varying the proportion of TB cases treated as in-patients and out-patients was calculated using Excel.

RESULTS

Nearly 90% (239/269) of notified TB cases received hospitalised care in 1994-1995. The cost of treatment for hospitalised patients (mean length of stay 2 weeks) was AU$5447 per patient, with a total cost of $1,301,833. Hospitalisation comprised 60% of the total cost of treatment. The cost of out-patient treatment was $2260 per patient. If 90% of patients were treated on an out-patient basis, the total cost would be $693,670. We estimated that it would be feasible to treat at least 55% of TB patients as out-patients, reducing costs by nearly 30%.

CONCLUSIONS

Routine hospitalisation for patients with uncomplicated TB is not necessary, but is often used in industrialised countries. More cost-effective use of resources can be achieved by giving initial TB treatment on an out-patient basis rather than in hospital for a greater proportion of cases.

Modelling strategies for reducing pharmaceutical costs in hospital

OBJECTIVE

To describe drug utilization and cost in a large hospital and to compare the impact of different strategies on cost associated with drug prescribing.

DESIGN

Retrospective data on drug utilization and cost, linked to patient clinical data and prescriber data from November 1998 were analyzed and modelled.

MAIN OUTCOME MEASURES

Impact of different strategies for cost control.

SETTING

A large hospital in Sydney, Australia.

RESULTS

The mean cost of drugs per episode of care was 28 Australian dollars. Of all drug costs, 79% was incurred by medical units and 14% by surgical units. Oncology accounted for 42% and inpatients for 91% of drug costs. Although section-100 (S-100) drugs incurred a high cost (640 dollars) per episode of care, there were only 41 episodes where S-100 drugs (expensive, restricted drugs) were used, and the total cost of S-100 drugs was only 3.7% of the total cost to the hospital. Antibiotics were the most commonly prescribed drug category, prescribed in 14% of all hospital episodes, and accounting for 14% of total drug costs. Anti-ulcer drugs were the next most costly group, accounting for 7% of total drug costs. A 20% reduction in use of antibiotics would save four times that (233,832 dollars pa) of a 20% reduction in use of S-100 drugs (61,392 dollars pa).

DISCUSSION

Our study suggests that reducing inappropriate use of high volume drugs such as antibiotics could be more effective in optimising health facility drug budgets than attempts concentrating solely on reducing use of high cost drugs alone. Moreover our study suggests that systematic measurement of drug utilisation patterns is a key element of drug cost control strategies.

No evidence for multiple-drug prophylaxis for tuberculosis compared with isoniazid alone in Southeast Asian refugees and migrants: completion and compliance are major determinants of effectiveness

BACKGROUND

The use of multiple-drug prophylaxis for tuberculosis (TB) has not been shown to be more effective than prophylaxis with isoniazid alone. The boundary between inactive pulmonary TB (class 4 TB) and culture-negative "active" pulmonary TB (class 3 TB) is often unclear, as is the intention to treat such patients as a preventive measure or as a curative measure.

METHODS

We compared the effectiveness of single drug preventive therapy with isoniazid to the effectiveness of multiple drug preventive therapy for patients with asymptomatic, inactive TB, in a retrospective cohort study of 984 Southeast (SE) Asian migrants and refugees who received prophylaxis between 1978 and 1980.

RESULTS

The rate of TB developing in this cohort was 122 per 100,000 person-years. There was no significant difference in development of TB between people who received isoniazid only and those who received multiple drugs. The only significant predictor of TB was noncompletion of prophylaxis [relative risk (RR) = 62, 95% confidence interval (CI) = 20-194]. Subgroup analysis on people who had completed therapy showed noncompliance as a significant predictor of TB (RR = 16, 95% CI = 1.4-179). The risk of noncompletion (RR = 4.7, 95% CI = 2.37-9.39, P < 0.0001) and noncompliance (RR = 2.2, 95% CI = 1.03-4.7, P = 0.03) was higher for patients who received multiple drugs compared with isoniazid alone. Multiple-drug therapy cost 30 times more than isoniazid alone.

CONCLUSIONS

We did not find evidence in support of the empirical practice of giving multiple drugs for prevention of TB. This practice is also more costly and more likely to result in noncompliance and adverse drug reactions.

Risk of transmission of tuberculosis among inmates of an Australian prison

In a prison in Victoria, Australia, our objectives were contact tracing of inmates and staff at risk of exposure to an identified index case; and to determine risk factors for prevalent and incident infection. Inmates and staff who were potentially exposed to the index case were screened with a Mantoux skin test and a questionnaire. Inmate movements within the prison were compared to movements of the index case. Logistic regression was used to determine risk factors for infection. The index case had smear positive, cavitating pulmonary tuberculosis (TB), which was undiagnosed for 3 months. This was the period of potential exposure. The prevalence of positive skin test reactions in 190 inmates and staff at the prison was 10%. Significant predictors of a positive skin test were being an inmate (odds ratio (OR) 15.5), older age (OR 8.3) and being born overseas (OR 10.7). Bacille Calmette Guerin (BCG) vaccination, proximity to the index case in various prison sites, duration of incarceration, number of incarcerations and number of inmates per cell were not significant. There were three recent skin test conversions from negative to positive, representing a conversion rate of 3.5%. We did not find evidence of significant transmission of TB from a single index case. The prevalence of infection in this Australian prison was lower than published rates in other countries. Better prison conditions and different demographics of prison inmates in Australia may explain these differences.

Unrecognised transmission of tuberculosis in prisons

BACKGROUND

Tuberculosis (TB) is a public health concern in correctional facilities. High turnover of inmate populations may preclude timely diagnosis of TB, so that unrecognised transmission may be common.

OBJECTIVE

To determine the proportion of inmates with new skin test conversions who had identifiable exposure to diagnosed cases of TB in the correctional system, and to test the hypothesis that source cases of TB may be undiagnosed during incarceration.

SETTING

Maryland Division of Corrections, USA.

SUBJECTS

All inmates whose skin test converted from negative to positive at annual screening.

DESIGN

All cases of TB in inmates, diagnosed in the prisons during the relevant time period, were identified. Movements of skin test converters and potential source cases within the prisons were matched. We then matched all inmates discharged from the prison system with all new cases of tuberculosis notified to the Maryland Department of Health & Mental Hygiene tuberculosis registry in 1994.

RESULTS

The inmate turnover was 21% per year. Probable exposure to a diagnosed source case was found in 13% of converters, possible exposure in 10% and no exposure in 72%. In a further 5% exposure status could not be determined. We identified four cases of pulmonary tuberculosis notified to the state in 1994, within 3 months of discharge in released inmates, who were not known to have tuberculosis whilst incarcerated.

CONCLUSIONS

Significant transmission of TB due to undiagnosed index cases may occur in prisons due to high population turnover. New skin test conversions in inmates should be treated as new infection, even in the absence of identifiable exposure to TB.

Longitudinal incidence of tuberculosis in South-East Asian refugees after re-settlement

SETTING

A State refugee screening programme in Victoria.

OBJECTIVE

To determine the longitudinal incidence of tuberculosis (TB) in South-East Asian refugees in the first five years after re-settlement, and to determine predictors of risk.

DESIGN

A retrospective cohort study of 1101 refugees from Laos, Cambodia and Vietnam screened for TB after arrival in Australia, in the 6-month period from July 1989 to January 1990. Incident cases of TB were identified by matching the refugee database with the TB notification database for 1989-1994, giving five years of follow-up data. Preventability was assessed for incident cases by reviewing medical records.

MAIN OUTCOME

The development of active tuberculosis in the first five years after re-settlement.

RESULTS

The incidence of active TB was 363/100000 during the first year after re-settlement, and 109/100000/year during the first five years. There were no incident cases of TB in refugees with initial skin test reactions <10 mm. Skin test reaction size was the only predictor of risk of TB.

CONCLUSIONS

There is a high risk of tuberculosis in South-East Asian refugees, particularly in the first year after re-settlement. This risk decreases with time. Migration stress, concurrent illnesses and poor nutrition may be explanations for this observation. Refugees are at high risk for TB, even after pre- and post-migration screening, emphasising the importance of preventive therapy and follow up in this group.

Predictors of length of stay for transurethral prostatectomy in Victoria

BACKGROUND

Transurethral resection of prostate (TURP) is among the top 10 surgical conditions that account for hospital admission in Victoria. Bed utilization for TURP is an increasing concern in current times. This paper describes trends in length of stay (LOS) and identifies predictors of LOS for TURP in Victoria.

METHODS

Trends in TURP were studied using ICD-9-CM coded Victorian hospital morbidity data from public hospitals from 1987/88 to 1994/95. Detailed morbidity data from the same source for the financial year 1995/96 were used to study predictors of LOS by logistic regression.

RESULTS

Length of stay decreased significantly between 1987 and 1995 from 10.6 to 6.1 days. The strongest predictor of increased LOS was admission through the emergency room (odds ratio (OR) 14.7; 95% confidence interval (CI) 11.8-18.3). Other significant predictors were older age, lower socio-economic status, presence of comorbid conditions, occurrence of procedural morbidity, and hospital type and location.

CONCLUSIONS

The trend in decreasing LOS may be explained by increasingly efficient bed management in hospitals who are faced with an increasing need for cost control. Advances in surgical techniques and peri-operative care have also contributed to the decrease in LOS. Other factors that influence LOS can be divided into three categories: intrinsic patient factors, such as co-morbid conditions; procedure-specific factors such as peri-operative morbidity; and intrinsic hospital factors relating to capacity and resources. Such determinants of LOS may be of value to policy makers when considering the effective application of newer methods for treatment of benign prostatic hyperplasia.

Tuberculosis in South-East Asian refugees after resettlement--can prevention be improved by better policy and practice?

OBJECTIVE

This study aimed to determine whether incident cases of tuberculosis (TB) in a cohort of South-East Asian refugees followed for 5 years after resettlement were potentially preventable and whether prevention of TB was optimal in a state refugee TB screening program in Victoria, Australia.

DESIGN

A retrospective cohort study of 1,101 refugees from Laos, Cambodia, and Vietnam screened for TB in the 6-month period from July 1989 to January 1990 was conducted. Incident cases of TB were identified by matching each refugee with the TB notification database for 5 years from the date of initial screening. Preventability was assessed for incident cases by reviewing medical records. Screening guidelines and practice were reviewed.

RESULTS

The main outcome was the preventability of cases of active tuberculosis that developed in the study population in the first 5 years after resettlement. The incidence of active TB was 363/100,000 during the first year and 109/100,000/year during the first 5 years. Five of six incident cases were assessed as potentially preventable, which if prevented would have resulted in an annual incidence of 18/100,000 over the first 5 years. Use of a more sensitive skin test definition of infection would have made an additional 245 refugees eligible for prevention and potentially prevented an additional 25 cases of TB over a lifetime.

CONCLUSIONS

There is a high incidence of tuberculosis among SE Asian refugees, particularly in the first year after resettlement. A large proportion of TB may be preventable. Improvement in case prevention may be possible with updated guidelines and better implementation of screening policy.

Impact of policy and practice on the effectiveness of contact screening for tuberculosis

BACKGROUND

Screening for tuberculosis is conducted because TB is a disease of public health importance that can be prevented if screening is followed by isoniazid prophylaxis for infected individuals. Screening alone is not effective unless that screening is rational and systematic and is followed by prevention where appropriate. Our aim was to consider whether the TB contact screening guidelines are evidence-based and appropriate, how well these guidelines are implemented, and how policy and practice impact on prevention.

METHODS

A cohort of 1,142 recent contacts screened in 1991 in Victoria, Australia, was studied. We evaluated the appropriateness of the screening guidelines and how well they were implemented and how the combination of these two factors impacted on the efficacy of the screening program.

RESULTS

The screening guidelines required updating and were not evidence-based. Chest radiograph (CXR) was overused and was the sole screening tool for nearly 40% (449/1,142) of contacts. Eighty percent of repeat CXRs were done following a normal initial study. Skin testing was underused. In nearly 60% (658/1,142) of all contacts, the presence or absence of infection could not be determined because a skin test was not done and the CXR, if done, was clear. Only 22% (38/175) of identified, eligible contacts received isoniazid preventive therapy.

CONCLUSIONS

Lack of evidence-based guidelines, as well as poor adherence to guidelines, resulted in an inefficient program. This problem may not be unique to the study setting, but cannot be identified without systematic program evaluation, for which we have provided a model.

Preventability of incident cases of tuberculosis in recently exposed contacts

SETTING

Contacts of tuberculosis (TB) cases are at risk for TB. If contact screening and intervention are effective, one would expect a reduced incidence of TB in contacts who have been screened.

OBJECTIVE

To measure the incidence of TB in contacts during a 2-year follow up, and to estimate the preventability of incident cases.

METHODS

A retrospective cohort study of 783 contacts screened in Victoria, Australia, in 1991. Contacts were matched with the TB registry for the following 2 years. Screening records were reviewed.

RESULTS

The rate of TB in contacts was 511/100000 population/year for the first 2 years. In Poisson regression models the only significant variable predicting disease was skin test reaction size. Six of eight incident cases were potentially preventable, with a lowest achievable incidence rate of 128/100000/year.

CONCLUSION

Contacts who underwent screening for TB through a state screening programme had a high incidence of TB during the 2 year follow up. Published rates of TB of 425-670/100000 in untreated contacts suggests that the Victorian screening programme had minimal impact on the natural history of disease progression. Intrinsic programme factors such as the appropriateness of the guidelines, adherence to guidelines and rates of preventive therapy need to be evaluated. The devolution of the TB programme in the 1980s also reduced its efficacy. Systematic assessment of screening programmes for efficacy and outcome is part of good public health practice.

Accuracy of injury coding in Victorian hospital morbidity data

In Victoria injury surveillance data are drawn from hospital morbidity data. The accuracy and reliability of these data are often questioned. We aimed to ascertain the reliability of injury data in the Victorian inpatient minimum database. A random sample of 546 public hospital separations with principal diagnosis ICD-9-CM codes 800-999 was selected from four metropolitan hospitals. Medical records were reviewed, and the hospital coding was compared with the record content. The frequency of error in any coding field was 73 per cent (349/480); of diagnosis error, 61 per cent (292/480); of procedure error, 45 per cent (168/370); of error in the principal diagnosis, 19 per cent (93/480); and of error in external-cause codes (E-codes), 16 per cent (75/480). Ninety-four per cent of errors (87/93) in the principal diagnosis involved recoding within the same group of codes. Only 6 per cent (6/93) were recoded to principal diagnoses other than injury. Sixty-two per cent (181/292) were errors of omission of codes for comorbid conditions. Nearly half the errors in the principal diagnosis were minor, involving the last two digits. E-codes were more complete than diagnosis codes. The best predictors of error in the principal diagnosis were greater length of stay, type of injury code (poisonings and toxic effects were associated with lower error rates) and death as the outcome. While selection of data from secondary diagnosis fields may not provide complete data, the use of the principal-diagnosis code and E-codes for injury surveillance is feasible and reliable. The database is a valuable source of injury surveillance data, bearing in mind the limitations of coded hospital morbidity data.

Changes in bed resources and admission patterns in acute public hospitals in Victoria, 1987-1995

OBJECTIVE

To describe changes in admission patterns, bed resources and hospital use in acute public hospitals and their relationship with early readmissions and interhospital transfers in Victoria between 1987 and 1995.

DESIGN

Descriptive study of longitudinal trends using data from the Victorian inpatient Minimum Database and the Acute Health Services Branch of the Department of Human Services, Victoria.

SETTING

State of Victoria.

MAIN OUTCOME MEASURES

Acute public hospital beds and hospital separations per 1000 population; separation type (same-day or longer); mean length of stay; interhospital transfers; and readmissions to the same hospital within 28 days.

RESULTS

Between 1987-88 and 1994-95, public hospital beds in Victoria decreased from 3.2 to 2.8/1000 population, and mean length of hospital stay decreased from 6.4 to 4.2 days. There was a significant direct correlation between number of beds/1000 and length of stay (r = 0.90; 95% confidence interval [CI], 0.52-0.98). Bed occupancy remained constant at 80%. Over the same period, same-day admissions increased from 22% to 42% of hospital separations, interhospital transfers increased from 2.7% to 4% of separations, and readmissions to the same hospital within 28 days for any reason increased from 12.4% to 15% of separations (21% increase). Beds/1000 were inversely correlated with interhospital transfers (r = -0.83; 95% CI, -0.31 to -0.97), while readmission rates were inversely correlated with beds/1000 (r = -0.89; 95% CI, -0.98 to -0.50) and length of hospital stay (r = -0.95; 95% CI, -0.99 to -0.74).

CONCLUSIONS

There were significant changes in the patterns of use of public hospitals between 1987 and 1995, possibly reflecting technological advances and changes in clinical practice, as well as policy to improve efficiency. Early readmission rates may be a useful proxy measure of potentially avoidable adverse outcomes.

Accuracy of ICD-9-CM codes in hospital morbidity data, Victoria: implications for public health research

Hospital morbidity data in the form of International classification of diseases, 9th revision, clinical modification codes are often used for epidemiological studies and disease surveillance. We aimed to evaluate the reliability of the Victorian In-patient Minimum Database for use in epidemiological studies and disease surveillance. Data from 1993-94 were collected, as part of a coding audit of public hospitals in Victoria, from 7052 randomly selected records. The frequency of discrepancy in any coding field was 53 per cent, and of discrepancy in the principal diagnosis, 22 per cent. New Australian national diagnosis-related group (ANDRG) codes were assigned as a result of discrepancy in 13.6 per cent of cases. Discrepancy rates increased with increasing rarity of ANDRG, from 50 per cent to 56 per cent. Predictors of change in ANDRG assignment were discrepancy in the principal diagnosis, ANDRG frequency of over 0.6 per cent, more than three diagnoses, medical ANDRGs, length of stay over five days and rural hospitals. Rates of any discrepancy increased from 36 per cent in patients with one diagnosis to 94 per cent in patients with 12 diagnoses. The discrepancy rates were consistent with those of other studies. Coding discrepancy is likely to be caused by universal difficulties associated with the coding of hospital records, rather than any unique local problems. The predictors of discrepancy suggest that more complex cases are more prone to coding discrepancy. In areas where the database is less reliable, use of a supplementary data source, such as link-age studies, would improve reliability.

Impact of tuberculosis control measures and crowding on the incidence of tuberculous infection in Maryland prisons

Our aim was to determine the incidence of tuberculin skin test (TST) conversion in the Maryland state correctional system. We conducted a historical longitudinal cohort study. A sample of 1,289 inmates, incarcerated in 16 of 23 prisons, who had a negative TST and a second test within 24 months was selected. The incidence of recent conversion was 6.3 per 100 person-years. Risk factors for conversion included high prison-population density (relative risk [RR] = 2.4; 95% confidence interval [CI], 1.5-3.8) and incarceration in a higher-security institution (RR = 2.4; 95% CI, 1.4-4.3). Incarceration in an institution with higher levels of isoniazid prophylaxis (> 65% of TST positives) reduced the risk of infection by 50% (RR = 0.5; 95% CI, 0.3-0.7). Crowding was strongly correlated with risk of conversion (r = 0.83; P < .001), while rates of isoniazid prophylaxis initiation were inversely correlated with risk of infection (r = -0.82; P < .001). In stepwise regression, higher prison-population density was the strongest predictor of increased infection. In a final model, inclusion of the rate of isoniazid prophylaxis initiation reduced the risk associated with crowding (RR = 1.4; P = .4). Annual screening programs for prisons can identify recent conversions that may not otherwise be detected.