Smoking and use of primary care services : findings from a population-based cohort study linked with administrative claims data

Background: Available evidence suggests that smokers have a lower propensity than others to use primary care services. But previous studies have incorporated only limited adjustment for confounding and mediating factors such as income, access to services and health status. We used data from a large prospective cohort study (the 45 and Up Study), linked to administrative claims data, to quantify the relationship between smoking status and use of primary care services, including specific preventive services, in a contemporary Australian population. Methods: Baseline questionnaire data from the 45 and Up Study were linked to administrative claims (Medicare) data for the 12-month period following study entry. The main outcome measures were Medicare benefit claimed for unreferred services, out-of-pocket costs (OOPC) paid, and claims for specific preventive services (immunisations, health assessments, chronic disease management services, PSA tests and Pap smears). Rate ratios with 95% confidence intervals were estimated using a hierarchical series of models, adjusted for predisposing, access-and health-related factors. Separate hurdle (two part) regression models were constructed for Medicare benefit and OOPC. Poisson models with robust error variance were used to model use of each specific preventive service. Results: Participants included 254,382 people aged 45 years and over of whom 7.3% were current smokers. After adjustment for predisposing, access-and health-related factors, current smokers were very slightly less likely to have claimed Medicare benefit than never smokers. Among those who claimed benefit, current smokers claimed similar total benefit, but recent quitters claimed significantly greater benefit, compared to never-smokers. Current smokers were around 10% less likely than never smokers to have paid any OOPC. Current smokers were 15-20% less likely than never smokers to use immunisations, Pap smears and prostate specific antigen tests. Conclusions: Current smokers were less likely than others to use primary care services that incurred out of pocket costs, and specific preventive services. This was independent of a wide range of predisposing, access-and health-related factors, suggesting that smokers have a lower propensity to seek health care. Smokers may be missing out on preventive services from which they would differentially benefit

Using linked birth, notification, hospital and mortality data to examine false-positive meningococcal disease reporting and adjust disease incidence estimates for children in New South Wales, Australia

Meningococcal disease is a rare, rapidly progressing condition which may be difficult to diagnose, disproportionally affects children, and has high morbidity and mortality. Accurate incidence estimates are needed to monitor the effectiveness of vaccination and treatment. We used linked notification, hospital, mortality and birth data for all children of an Australian state (2000–2007) to estimate the incidence of meningococcal disease. A total of 595 cases were notified, 684 cases had a hospital diagnosis, and 26 cases died from meningococcal disease. All deaths were notified, but only 68% (466/684) of hospitalized cases. Of non-notified hospitalized cases with more than one clinical admission, most (90%, 103/114) did not have meningococcal disease recorded as their final diagnosis, consistent with initial ‘false-positive’ hospital meningococcal disease diagnosis. After adjusting for false-positive rates in hospital data, capture– recapture estimation suggested that up to four cases of meningococcal disease may not have been captured in either notification or hospital records. The estimated incidence of meningococcal disease in NSW-born and -resident children aged 0–14 years was 5•1–5•4 cases/100 000 child years at risk, comparable to international estimates using similar methods, but lower than estimates based on hospital data

Constructing a synthetic longitudinal health dataset for data mining

The traditional approach to epidemiological research is to analyse data in an explicit statistical fashion, attempting to answer a question or test a hypothesis. However, increasing experience in the application of data mining and exploratory data analysis methods suggests that valuable information can be obtained from large datasets using these less constrained approaches. Available data mining techniques, such as clustering, have mainly been applied to cross-sectional point-in-time data. However, health datasets often include repeated observations for individuals and so researchers are interested in following their health trajectories. This requires methods for analysis of multiple-points-over-time or longitudinal data. Here, we describe an approach to construct a synthetic longitudinal version of a major population health dataset in which clusters merge and split over time, to investigate the utility of clustering for discovering time sequence based patterns

Access to subsidized smoking cessation medications by Australian smokers aged 45 years and older : a population-based cohort study

Introduction: The principal aim of this study was to assess the accessibility of subsidized cessation medications to socioeconomically disadvantaged smokers, including smokers living in regional and remote communities. Methods: Analyses used baseline questionnaire and linked Pharmaceutical Benefits Scheme data for 18 686 regular smokers participating in the 45 and Up Study, a large-scale Australian cohort study of people aged 45 years and older. Participants who were dispensed nicotine replacement therapy, varenicline, or bupropion were identified from the Pharmaceutical Benefits Scheme data, which provide an essentially complete record of participants' access to subsidized pharmaceuticals. Associations between the supply of each pharmacotherapy and a range of sociodemographic and health-related variables were evaluated using multiple logistic regression. Results: The odds that participants were supplied with a cessation medication declined markedly with increasing age for participants older than 60 years and were substantially higher for participants who smoked 20 or more cigarettes/day than for participants who smoked fewer than 10 cigarettes/day. Participants with no formal qualification and those residing in socioeconomically disadvantaged areas had higher odds of receiving nicotine replacement therapy or varenicline than university-educated participants and participants living in the least disadvantaged areas. There was no evidence that participants residing in regional and remote communities had lower odds of receiving a cessation medication than participants residing in major cities. Conclusions: Older Australian smokers' access to cessation pharmacotherapies is determined predominantly by age and daily cigarette consumption and does not appear to be limited by educational achievement, socioeconomic disadvantage, or remoteness. Implications: Promoting the use of cessation medications is a principal measure proposed to achieve Australia's National Tobacco Strategy 2012-2018 goal of reducing cigarette consumption among socioeconomically disadvantaged smokers. The results of this large-scale cohort study indicate that access to cessation pharmacotherapies is determined primarily by age and daily cigarette consumption, and is not limited by socioeconomic circumstances, providing some reassurance that existing government subsidies are sufficient to ensure that pharmaceutical aids are accessible to all Australian smokers

A nested case-control analysis of self-reported physical functioning after total knee replacement surgery in the 45 and Up Study cohort

Objectives: The rate of total knee arthroplasty surgery (TKA) is rising in Australia despite varying impacts of TKA on physical function (PF) in population-based studies. There are potentially modifiable risk factors that could enhance PF after TKA, so we evaluated (1) the levels of PF in persons with TKA and the rest of the population, (2) potentially modifiable characteristics of those reporting poor PF after TKA. Design: Nested case-control study. Setting: Population-based cohort study in New South Wales, Australia. Participants: Members of a large (n=267 151) cohort study recruited by a self-completed, mailed questionnaire from 2006 to 2008. After exclusions (for hip arthroplasty, partial TKA, missing important variables and mismatching TKA status between self-reported and hospital record data), this study included 205 148 participants. Primary and secondary outcomes: Primary outcome, Medical Outcomes Study Physical Function scale (MOS-PF). Secondary outcome, dispensings of analgesics or anti-inflammatory drugs. Results: We found 2916 TKA participants and 202 232 participants with no TKA (confirmed across datasets). Persons with TKA had a lower MOS-PF (59.9, 95% CI 58.5 to 60.6) than those without TKA (83.8, 95% CI 83.7 to 83.9). In the matched analysis, the TKA group had a lower MOS-PF (59.9, 95% CI 59.9 to 62.4) than those without TKA (68.4, 95% CI 67.8 to 69.0). In persons with TKA, lower levels of MOS-PF were associated with low self-rated health, high psychological distress, comorbidity, greater age, recent treatment for osteoarthritis and use of paracetamol. Women had an MOS-PF that was 11.6 points (95% CI 9.5 to 13.8) lower than men. Conclusions: Several modifiable risk factors have been identified to influence PF in persons receiving TKA, with notable differences between sexes. The importance of these risk factors should be examined in incident TKA to test if early identification and intervention for individuals can improve outcomes

Factors influencing adherence in long-term use of statins

Purpose: To assess the factors influencing adherence in long-term medication use as exemplified by statins. Methods: Data from an in-depth survey of Australians aged 45 years and over were linked to national prescription reimbursement data to assess medication possession ratio (MPR) for statins for the middle two years of a four-year period of statin possession. Poisson regression was used to calculate the relative risk (RR) for adherence (MPR≥80%) for patient characteristics and factors related to access to and need for health care services. Separate models were fit for patients receiving healthcare concession subsidies and those who do not ('general beneficiaries'). Results: In the analysis, 42492 concessional and 16110 general beneficiary patients were included, with 80.1% and 56.7% showing MPR≥80%, respectively. In both models, RR for adherence was significantly elevated for older (age 65+) and less healthy (worse self-rated health, pre-existing heart condition or obese) individuals, and for those who had private health insurance. Significantly lower RR (i.e. more non-adherence) was found for individuals reporting speaking a language other than English at home, who were smokers, were employed, and had higher levels of education, and for those who reported psychological distress. Income had no significant relationship with adherence, and the pattern of adherence by remoteness of area of residence was inconsistent. Conclusions: Poor adherence in long-term use of statins is commonplace, but a number of key predictors-including age, language other than English spoken at home, smoking status and psychological distress-are readily assessable by the prescribing practice

Estimating the burden of pertussis in young children on hospitals and emergency departments : a study using linked routinely collected data

Potential underestimation of the health system burden of pertussis was investigated by linking administrative datasets including pertussis notifications, hospitalizations and emergency department (ED) presentations for 1 304 876 children aged <15 years in NSW, Australia. From 2005 to 2008, 3006 children had a pertussis notification, 455 were hospitalized and 644 had an ED presentation with a coded diagnosis of pertussis. Linking hospital and ED records with pertussis notifications identified 140 hospitalizations and 735 ED presentations which occurred ±7 days from notification but did not have a diagnosis of pertussis recorded. These additional events were more likely to have a diagnosis of bronchiolitis, upper respiratory infection and cough compared to all other admissions and presentations. Including these additional events significantly increased the proportion of notified cases that were hospitalized or visited EDs, particularly for those aged 5 to <15 years. Linked administrative data allowed more comprehensive estimation of the health system burden of pertussis

Inequalities in bariatric surgery in Australia : findings from 49 364 obese participants in a prospective cohort study

Objectives: To investigate variation, and quantify socioeconomic inequalities, in the uptake of primary bariatric surgery in an obese population. Design, setting and participants: Prospective population-based cohort study of 49 364 individuals aged 45-74 years with body mass index (BMI) >= 30 kg/m(2). Data from questionnaires (distributed from 1 January 2006 to 31 December 2008) were linked to hospital and death data to 30 June 2010. The sample was drawn from the 45 and Up Study (approximately 10% of New South Wales population aged 45 included, response rate approximately 18%). Main outcome measures: Rates of bariatric surgery and adjusted rate ratios (RRs) in relation to health and sociodemographic characteristics. Results: Over 111 757 person-years (py) of follow-up, 312 participants had bariatric surgery, a rate of 27.92 per 10 000 py (95% Cl, 24.91-31.19). Rates were highest in women, those living in major cities and those with diabetes, and increased significantly with a higher BMI and number of chronic health conditions. Adjusted RRs were 5.27 (95% CI, 3.18-8.73) for those with annual household income >=$70 000 versus those with household income <$20 000, and 4.01 (95% Cl, 2.41-6.67) for those living in areas in the least disadvantaged quintile versus those in the most disadvantaged quintile. Having versus not having private health insurance (age- and sex-adjusted RR, 9.25; 95% Cl, 5.70-15.00) partially explained the observed inequalities. Conclusions: Bariatric surgery has been shown to be cost-effective in treating severe obesity and associated illnesses. While bariatric surgery rates in Australia are higher in those with health problems, large socioeconomic inequalities are apparent. Our findings suggest these procedures are largely available to those who can afford private health insurance and associated out-of-pocket costs, with poor access in populations who are most in need. Continuing inequalities in access are likely to exacerbate existing inequalities in obesity and related health problems

Quantifying under-reporting of pathology tests in Medical Benefits Schedule claims data

Objective We investigated the completeness of recording of pathology tests in Australian Medical Benefits Schedule (MBS) claims data, using the example of the prostate-specific antigen (PSA) test. With some exceptions, MBS claims data records only the three most expensive pathology items in an episode of care, and this practice ('episode coning') means that pathology tests can be under-recorded. Methods The analysis used MBS data for male participants in the 45 and Up Study. The number and cost of items in each episode of care were used to determine whether an episode contained a PSA screening test (Item 66655), or could have lacked a record of this item because of episode coning. Results MBS data for 1070392 episodes involving a request for a pathology test for 118074 men were analysed. Of these episodes, 11% contained a request for a PSA test; a further 7.5% may have been missing a PSA request that was not recorded because of episode coning. Conclusions It is important to consider under-reporting of pathology tests as a result of episode coning when interpreting MBS claims data. Episode coning creates uncertainty about whether a person has received any given pathology test. The extent of this uncertainty can be estimated by determining the proportion of episodes in which the test may have been performed but was not recorded due to episode coning. What is known about the topic Medical Benefits Schedule (MBS) claims data are a key resource for Australian health researchers. What does this paper add We investigated a feature of MBS claims data known as episode coning, which may cause some pathology tests to be under-reported. Using the example of requests for PSA tests, we estimated the uncertainty in the amount of use of PSA tests introduced by episode coning. What are the implications for practitioners Researchers using MBS data to identify use of specific pathology tests need to be aware of under-reporting caused by episode coning, and to estimate and report the uncertainty that this introduces into their findings

Enhancing ascertainment of smoking in pregnancy using linked population health data

Objectives: To enhance ascertainment of smoking in pregnancy (SIP) using the linkage of population health records