Original Article
Do women who intermittently attend breast screening differ from those who attend every invitation and those who never attend?
J Med Screen 2014, Vol. 21(2) 98–103 ! The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0969141314533677 msc.sagepub.com
C Coyle1, H Kinnear2, M Rosato3, A Mairs4, C Hall5 and D O’Reilly6
Abstract Objectives: Analysis of screening uptake usually dichotomizes women into attenders and non-attenders, though many women respond positively to some but not all invitations. This paper studies these intermittent attenders. Methods: A cohort of 8,571 women invited for consecutive breast screens in the Northern Ireland Breast Screening Programme were followed in a study linking screening and census records. Multivariate logistic analysis was used to analyze the characteristics of those who attended both times (consistent), once (intermittent or ‘one-time only’), or not at all (nonattenders). Results: Overall, 15.5% of women attended once and 13.4% were non-attenders. Non-attenders were characteristically disadvantaged (as measured by social renting, car access, and employment status), less likely to be married, and more likely to be healthy. One-time attenders were younger, and suffering poor health, though there was no association with either social renting or employment status. Privately rented accommodation and city living was associated with both one-time attendance and non-attendance. Conclusions: One-time attenders are an important and distinct subgroup of screening invitees in this analysis. Their distinct characteristics suggest that transitory factors, such as change in marital status, ill-health, or addressing difficulties through change of residence are important. These distinct characteristics suggest the need for different approaches to increase attendance, among both intermittent attenders and those not attending at all. Keywords Breast Screening, attendance, re-attendance, record linkage Date received: 5 November 2013; accepted: 9 April 2014
Introduction Cancer is a leading cause of mortality worldwide and accounts for three of the top ten causes of death for high income countries.1 The World Health Organization (WHO) has identified three evidence-based strategies to reduce and control the global burden of cancer: preventing cancer from occurring, detecting cancer earlier, and managing patients with cancer.2 Early detection is predicated on the assumption that the earlier in its natural history a cancer is detected, the more effective treatment is likely to be.1 In the United Kingdom (UK) recommendations regarding screening programmes are produced by the National Screening Committee (UK NSC), and based on evidence from randomized controlled trials demonstrating that the programme reduces mortality and morbidity.3 However, for these programmes to be effective, the attendance of the target population at screening must be consistent and at the recommended intervals a one-off attendance will not ensure early detection of cancer.4 Currently, UK programmes include screening for cervical, breast, and more recently bowel cancer.
Yet, despite these being free at the point of delivery across the UK, a significant proportion of people do not take up the invitation to attend. For example, between 2002 and 2010 the breast screening programme in England has (for women aged 53-64) shown average yearly coverage of approximately 75% for those invited.5 Investment is therefore required to promote and encourage uptake of
1
Registrar in Public Health, Public Health Agency, Belfast Post Doctoral Research Fellow, Centre for Public Health, Queen’s University Belfast 3 Senior Research Fellow; Bamford Centre for Mental Health and Wellbeing; University of Ulster; Northern Ireland 4 Director Breast Screening Service Northern Ireland, Public Health Agency, Belfast, Northern Ireland 5 Information Officer, Quality Assurance Reference Centre, Public Health Agency, Belfast, Northern Ireland 6 Senior Lecturer, Centre for Public Health, Queen’s University Belfast 2
Corresponding author: Heather Ruth Kinnear, Queen‘s University Belfast Mulhouse Building Grosvenor Road Belfast, BT12 6DP United Kingdom. Email: [email protected]
Downloaded from msc.sagepub.com at VIRGINIA COMMONWEALTH UNIV on March 13, 2015
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screening across the target population, so that any potential benefits of the programme are realized. There is evidence to suggest that levels of nonattendance at screening are not uniformly distributed throughout the eligible population. For example Chui (2003) noted differences in attendance at screening services by social and ethnic background.6 However, because of a dearth of UK-based research, an accurate picture of variation in screening uptake among different societal groups is currently not available.6 While targeted efforts to improve uptake and repeat attendance at screening programmes have the ability to improve outcomes, these can be effective only when it is clear how uptake and re-attendance vary across the population. Most published studies concentrate on comparing women who attend for screening with those who do not. This ignores an important intermediate group who attend intermittently, and who may have different characteristics and reasons for non-attendance from those who consistently attend. This study explores the demographic, socioeconomic, and baseline health characteristics associated with uptake and re-attendance over two successive rounds of screening in the Northern Ireland Breast Screening Programme (NIBSP).
Methods The dataset was constructed by linking data from the National Breast Screening System (NBSS) to the Northern Ireland Longitudinal Study (NILS). The process is described more fully elsewhere.7 The analysis dataset comprised women identified in the Census, and followed up over two screening cycles to identify attendance patterns. The NBSS holds information about eligibility and uptake of breast screening in Northern Ireland. NILS is a representative 28% sample (approximately 500,000 people) of the Northern Ireland population, formed by the linkage of the Health Card Registration system and the 2001 Census returns.8 The screening data and NILS data were linked using an encrypted Health Service identifier as the matching field, a process carried out by the respective data custodians within the secure setting in the Northern Ireland Statistics and Research Agency (NISRA). The key matching field (Health and Care Number) was subsequently removed, and the resultant anonymized research dataset held in a secure setting by the Registrar General for Northern Ireland. At no time were patient identifiable data available to the research team. The study was approved by the local ethics committee (ref: 07/NIR01/90). Women aged between 48 and 52 at the 2001 Census and who were subsequently invited for two breast screens between April 2001 and October 2007, with the initial screen being their first, were included. If an invited woman reorganized her appointment and attended the screen at any stage within six months of the original invitation, she was included as an attendee. This covered two complete screening rounds, from 2001–2004 and 2005– 2007. The lower age allowed inclusion of women who
would have reached the eligible age for a first screen (50 years) by the end of the first screening round in 2004. Women living in communal establishments, or who were receiving treatment or otherwise being investigated (including repeat mammograms for technical reasons), and women with incomplete information (from NBSS or NILS) were excluded from the analysis. The sample included a cohort of 8,571 women who received two screening invitations during the study period and who had corresponding Census-based information available. The cohort was split into three distinct groups, based on attendance at both screening rounds. The first group (consistent) comprised women who attended both screening appointments. A second (intermittent or ‘one-time’) group comprised women attended only one of the two screening appointments (589 women attended the first screen but not the second, and 738 women attended the second but not the first screen). Initial analyses showed that women who attended only the first screen were broadly similar, in terms of age and demographic characteristics, to women who attended only the second screen. Women attending the second but not the first screens were generally of a higher socio-economic status than women who attended the first but not the second. The final group (non-attenders) included women who did not attend either screen. All characteristics of women in the cohort were as recorded on the Census form and selected as factors shown, from other studies, to be associated with screening uptake. Age was included as an independent variable, although the group of women was very similar in age and fell within a small age range (categorized as
Do women who intermittently attend breast screening differ from those who attend every invitation and those who never attend?
J Med Screen 2014, Vol. 21(2) 98–103 ! The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0969141314533677 msc.sagepub.com
C Coyle1, H Kinnear2, M Rosato3, A Mairs4, C Hall5 and D O’Reilly6
Abstract Objectives: Analysis of screening uptake usually dichotomizes women into attenders and non-attenders, though many women respond positively to some but not all invitations. This paper studies these intermittent attenders. Methods: A cohort of 8,571 women invited for consecutive breast screens in the Northern Ireland Breast Screening Programme were followed in a study linking screening and census records. Multivariate logistic analysis was used to analyze the characteristics of those who attended both times (consistent), once (intermittent or ‘one-time only’), or not at all (nonattenders). Results: Overall, 15.5% of women attended once and 13.4% were non-attenders. Non-attenders were characteristically disadvantaged (as measured by social renting, car access, and employment status), less likely to be married, and more likely to be healthy. One-time attenders were younger, and suffering poor health, though there was no association with either social renting or employment status. Privately rented accommodation and city living was associated with both one-time attendance and non-attendance. Conclusions: One-time attenders are an important and distinct subgroup of screening invitees in this analysis. Their distinct characteristics suggest that transitory factors, such as change in marital status, ill-health, or addressing difficulties through change of residence are important. These distinct characteristics suggest the need for different approaches to increase attendance, among both intermittent attenders and those not attending at all. Keywords Breast Screening, attendance, re-attendance, record linkage Date received: 5 November 2013; accepted: 9 April 2014
Introduction Cancer is a leading cause of mortality worldwide and accounts for three of the top ten causes of death for high income countries.1 The World Health Organization (WHO) has identified three evidence-based strategies to reduce and control the global burden of cancer: preventing cancer from occurring, detecting cancer earlier, and managing patients with cancer.2 Early detection is predicated on the assumption that the earlier in its natural history a cancer is detected, the more effective treatment is likely to be.1 In the United Kingdom (UK) recommendations regarding screening programmes are produced by the National Screening Committee (UK NSC), and based on evidence from randomized controlled trials demonstrating that the programme reduces mortality and morbidity.3 However, for these programmes to be effective, the attendance of the target population at screening must be consistent and at the recommended intervals a one-off attendance will not ensure early detection of cancer.4 Currently, UK programmes include screening for cervical, breast, and more recently bowel cancer.
Yet, despite these being free at the point of delivery across the UK, a significant proportion of people do not take up the invitation to attend. For example, between 2002 and 2010 the breast screening programme in England has (for women aged 53-64) shown average yearly coverage of approximately 75% for those invited.5 Investment is therefore required to promote and encourage uptake of
1
Registrar in Public Health, Public Health Agency, Belfast Post Doctoral Research Fellow, Centre for Public Health, Queen’s University Belfast 3 Senior Research Fellow; Bamford Centre for Mental Health and Wellbeing; University of Ulster; Northern Ireland 4 Director Breast Screening Service Northern Ireland, Public Health Agency, Belfast, Northern Ireland 5 Information Officer, Quality Assurance Reference Centre, Public Health Agency, Belfast, Northern Ireland 6 Senior Lecturer, Centre for Public Health, Queen’s University Belfast 2
Corresponding author: Heather Ruth Kinnear, Queen‘s University Belfast Mulhouse Building Grosvenor Road Belfast, BT12 6DP United Kingdom. Email: [email protected]
Downloaded from msc.sagepub.com at VIRGINIA COMMONWEALTH UNIV on March 13, 2015
Coyle et al.
99
screening across the target population, so that any potential benefits of the programme are realized. There is evidence to suggest that levels of nonattendance at screening are not uniformly distributed throughout the eligible population. For example Chui (2003) noted differences in attendance at screening services by social and ethnic background.6 However, because of a dearth of UK-based research, an accurate picture of variation in screening uptake among different societal groups is currently not available.6 While targeted efforts to improve uptake and repeat attendance at screening programmes have the ability to improve outcomes, these can be effective only when it is clear how uptake and re-attendance vary across the population. Most published studies concentrate on comparing women who attend for screening with those who do not. This ignores an important intermediate group who attend intermittently, and who may have different characteristics and reasons for non-attendance from those who consistently attend. This study explores the demographic, socioeconomic, and baseline health characteristics associated with uptake and re-attendance over two successive rounds of screening in the Northern Ireland Breast Screening Programme (NIBSP).
Methods The dataset was constructed by linking data from the National Breast Screening System (NBSS) to the Northern Ireland Longitudinal Study (NILS). The process is described more fully elsewhere.7 The analysis dataset comprised women identified in the Census, and followed up over two screening cycles to identify attendance patterns. The NBSS holds information about eligibility and uptake of breast screening in Northern Ireland. NILS is a representative 28% sample (approximately 500,000 people) of the Northern Ireland population, formed by the linkage of the Health Card Registration system and the 2001 Census returns.8 The screening data and NILS data were linked using an encrypted Health Service identifier as the matching field, a process carried out by the respective data custodians within the secure setting in the Northern Ireland Statistics and Research Agency (NISRA). The key matching field (Health and Care Number) was subsequently removed, and the resultant anonymized research dataset held in a secure setting by the Registrar General for Northern Ireland. At no time were patient identifiable data available to the research team. The study was approved by the local ethics committee (ref: 07/NIR01/90). Women aged between 48 and 52 at the 2001 Census and who were subsequently invited for two breast screens between April 2001 and October 2007, with the initial screen being their first, were included. If an invited woman reorganized her appointment and attended the screen at any stage within six months of the original invitation, she was included as an attendee. This covered two complete screening rounds, from 2001–2004 and 2005– 2007. The lower age allowed inclusion of women who
would have reached the eligible age for a first screen (50 years) by the end of the first screening round in 2004. Women living in communal establishments, or who were receiving treatment or otherwise being investigated (including repeat mammograms for technical reasons), and women with incomplete information (from NBSS or NILS) were excluded from the analysis. The sample included a cohort of 8,571 women who received two screening invitations during the study period and who had corresponding Census-based information available. The cohort was split into three distinct groups, based on attendance at both screening rounds. The first group (consistent) comprised women who attended both screening appointments. A second (intermittent or ‘one-time’) group comprised women attended only one of the two screening appointments (589 women attended the first screen but not the second, and 738 women attended the second but not the first screen). Initial analyses showed that women who attended only the first screen were broadly similar, in terms of age and demographic characteristics, to women who attended only the second screen. Women attending the second but not the first screens were generally of a higher socio-economic status than women who attended the first but not the second. The final group (non-attenders) included women who did not attend either screen. All characteristics of women in the cohort were as recorded on the Census form and selected as factors shown, from other studies, to be associated with screening uptake. Age was included as an independent variable, although the group of women was very similar in age and fell within a small age range (categorized as
