Cervical Abnormalities Are More Common among Indigenous than Other Australian Women: A Retrospective Record-Linkage Study, 2000-2011

Development and validation of an HPV infection knowledge assessment scale among Aboriginal and Torres Strait Islander Peoples

Background

An increased incidence of Human Papillomavirus (HPV) infection and its related cancers has been observed in recent years. Correct knowledge about HPV infection can lead to a significant decrease in transmission and a subsequent increase in vaccine uptake. Awareness and behavioural perception towards HPV infections are critical for improving HPV vaccination rates among Aboriginal and/or Torres Strait Islander Peoples. However, to the best of our knowledge, there has been no instrument designed to measure knowledge about HPV infection that is culturally appropriate and validated among Aboriginal and/or Torres Strait Islander People.

Aim

To address this research gap, this paper aims to examine the psychometric properties of the HPV Knowledge Tool (HPV-KT) in an Indigenous population sample from South Australia.

Methodology

Data from 747 Indigenous Australian Adults who participated in the 12-month follow-up of the HPV and Oropharyngeal Carcinoma in Indigenous Australians Study was utilised for this study. The psychometric properties examined included1) dimensionality and item redundancy; (2) network loadings; (3) model fit; (4) criterion validity; and (5) reliability. The network model was estimated using the Graphical Least Absolute Shrinkage and Selector Operator (GLASSO). Evaluation of the HPV-KT (10 items) dimensionality and item redundancy was conducted within the framework of Exploratory Graph Analysis (EGA). Reliability was evaluated with the McDonald's Omega (ω) coefficient.

Results

After the exclusion of two items, the HPV-KT exhibited good psychometric properties for Aboriginal and/or Torres Strait Islander Peoples. The two dimensions of "General HPV Knowledge" and "Commonness of HPV" were identified. The dimension of "Commonness of HPV" displayed poor reliability, so a sum score for this subscale is not recommended (i.e. the items can still be used individually) The network model of the 7-item HPV-KT was fitted in the validation sample and model fit was adequate (x2 (7) = 17.17, p < 0.016; CFI = 0.980; TLI = 0.94; RMSEA = 0.063, 90% CI = 0.025-0.010). Furthermore, the reliability of the "General HPV Knowledge" subscale (ω = 0.76, 95% CI: 0.72-0.79), while the reliability of the "Commonness of HPV" subscale (ω = 0.58, 95% CI0.58-0.88) was poor.

Conclusion

The HPV-KT was adapted for an Aboriginal and/or Torres Strait Islander population and is readily available for future use in Australia. The addition of items assessing specifications of HPV infection, natural history and behaviour will improve the reliability and usability to assess the level of accurate knowledge about HPV infection. Future studies should investigate the possibility of developing new items for the dimension 'Commonness of HPV'.

Study protocol: Yarning about HPV Vaccination: a qualitative study of factors influencing HPV vaccination among Aboriginal and Torres Strait Islander adolescents in Australia

INTRODUCTION

Aboriginal and Torres Strait Islander women experience a higher burden of cervical cancer than non-Indigenous women in Australia. Cervical cancer is preventable partly through human papillomavirus (HPV) vaccination; in Australia, this is delivered through the national school-based immunisation programme. While HPV vaccination uptake is high among Australian adolescents, there remain gaps in uptake and completion among Aboriginal and Torres Strait Islander adolescents. This study aims to gain a comprehensive understanding of the barriers and facilitators to HPV vaccination uptake and completion among Aboriginal and Torres Strait Islander adolescents in Queensland, Australia.

METHODS AND ANALYSIS

The study will be guided by an Indigenist research approach and an ecological model for health promotion. Yarning, a qualitative Indigenous research method, will be conducted in up to 10 schools. Participants will include Year 7 (12/13 years old) Aboriginal and Torres Strait Islander adolescents; parents/caregivers; and local key informants and immunisation programme partners involved in the delivery of school-based HPV immunisation programme. Participants will be recruited through school representatives and investigator networks using purposive and snowball sampling and samples of convenience. Field notes, HPV vaccination clinic observations and sequential diagramming of the HPV vaccination process will be conducted. Thematic analysis of data will be led by Aboriginal and Torres Strait Islander researchers. Synthesised sequential diagrams of the process of HPV vaccination and qualitative themes summarising key findings will be produced.

ETHICS AND DISSEMINATION

The Aboriginal Health and Medical Research Council of New South Wales Ethics Committee (1646/20), the Australian National University Human Research Ethics Committee (HREC, 2020/478), the HREC of the Northern Territory Department of Health and Menzies School of Health Research (19-3484) and the Townsville Hospital and Health Service HREC (HREC/QTHS/73789) have approved the study. Dissemination will occur via conferences and peer-reviewed publications. Further dissemination will be determined in partnership with the Aboriginal and Torres Strait Islander Steering Committee, including Youth Representatives and Consultation Network.

Temporal and area-level variation in prevalence of high-grade histologically confirmed cervical abnormalities among Indigenous and non-Indigenous women, Queensland, Australia, 2008-2017

OBJECTIVE

Despite Australia's National Cervical Screening Program, Indigenous women have a disproportionately high burden of cervical cancer. We describe temporal and area-level patterns in prevalence of histologically conformed high-grade cervical abnormalities (hHGA) among cytologically screened women by Indigenous status.

METHODS

This was a population-based study of 2,132,925 women, aged 20-69, who underwent cervical screening between 2008 and 2017, in Queensland, Australia. Of these, 47,136 were identified as Indigenous from linked hospital records. Overall patterns in hHGA prevalence by Indigenous status were quantified using prevalence rate ratios (PrRR) from negative binomial models. Bayesian spatial models were used to obtain smoothed prevalence estimates of hHGA across 528 small areas compared to the state average. Results are presented as maps and graphs showing the associated uncertainty of the estimates.

RESULTS

Overall, screened Indigenous women had significantly higher hHGA prevalence than non-Indigenous women. However, the magnitude of the difference reduced over time (p < 0.001). Adjusted for age and area-level variables, Indigenous women had 36% higher hHGA prevalence (PrRR 1.36, 95% confidence interval [1.21-1.52]) than non-Indigenous women between 2013 and 2017. The overall effect of age decreased over time (p = 0.021). Although there was evidence of moderate spatial variation in 10-year prevalence estimates for both groups of women, the high levels of uncertainty for many estimates, particularly for Indigenous women, limited our ability to draw definitive conclusions about the spatial patterns.

CONCLUSIONS

While the temporal reduction in Indigenous: non-Indigenous differential in hHGA prevalence is encouraging, further research into the key drivers of the continuing higher risk among Indigenous women is warranted.

HPV vaccination coverage and course completion rates for Indigenous Australian adolescents, 2015

OBJECTIVE

To estimate human papillomavirus (HPV) vaccination coverage and course completion rates for Indigenous adolescents in four Australian states and territories.

PARTICIPANTS, SETTING

Adolescents who were 12 years old in 2015 and received the quadrivalent HPV vaccine (three doses: 0, 2, 6 months) as part of the National HPV Vaccination Program in 2015 or 2016 in New South Wales, Queensland, the Northern Territory, or the Australian Capital Territory.

MAIN OUTCOME MEASURES

Estimated HPV vaccination coverage by dose and by Indigenous status and sex, based on National HPV Vaccination Program Register data; vaccination course completion rates (proportion of dose 1 recipients who received dose 3) for 12-year-olds vaccinated during 2013-2016, by sex, jurisdiction, and Indigenous status.

RESULTS

Dose 1 coverage exceeded 80% for all Indigenous status/jurisdiction/sex groups (range, 83.3-97.7%). Coverage was similar for Indigenous and non-Indigenous girls in Queensland (87.3% v 87.0%), lower for Indigenous girls in the ACT (88.7% v 97.7%) and the NT (91.1% v 97.0%), and higher in NSW (95.9% v 89.9%); it was similar for Indigenous and non-Indigenous boys in all jurisdictions except the NT (88.6% v 96.3%). Dose 3 coverage (range, 61.2-87.7%) was markedly lower for Indigenous than non-Indigenous 12-year-olds in all jurisdictions, except for girls in NSW (82.6% v 83.6%).

CONCLUSION

HPV vaccine coverage is high, but course completion is generally lower for Indigenous adolescents. Strategies for improving completion rates for Indigenous Australians are needed to end the higher burden of cervical cancer among Indigenous than non-Indigenous women.

Aboriginal women have a higher risk of cervical abnormalities at screening; South Australia, 1993-2016

OBJECTIVE

Cervical cancer mortality has halved in Australia since the national cervical screening program began in 1991, but elevated mortality rates persist for Aboriginal and Torres Strait Islander women (referred to as Aboriginal women in this report). We investigated differences by Aboriginal status in abnormality rates predicted by cervical cytology and confirmed by histological diagnoses among screened women.

METHODS

Using record linkage between cervical screening registry and public hospital records in South Australia, we obtained Aboriginal status of women aged 20-69 for 1993-2016 (this was not recorded by the registry). Differences in cytological abnormalities were investigated by Aboriginal status, using relative risk ratios from mixed effect multinomial logistic regression modelling. Odds ratios were calculated for histological high grade results for Aboriginal compared with non-Aboriginal women.

RESULTS

Of 1,676,141 linkable cytology tests, 5.8% were abnormal. Abnormal results were more common for women who were younger, never married, and living in a major city or socioeconomically disadvantaged area. After adjusting for these factors and numbers of screening episodes, the relative risk of a low grade cytological abnormality compared with a normal test was 14% (95% confidence interval 5-24%) higher, and the relative risk of a high grade cytological abnormality was 61% (95% confidence interval 44-79%) higher, for Aboriginal women. The adjusted odds ratio of a histological high grade was 76% (95% confidence interval 46-113%) higher.

CONCLUSIONS

Ensuring that screen-detected abnormalities are followed up in a timely way by culturally acceptable services is important for reducing differences in cervical cancer rates between Aboriginal and non-Aboriginal women.

Time to clinical investigation for Indigenous and non-Indigenous Queensland women after a high grade abnormal Pap smear, 2000-2009

OBJECTIVES

To investigate time to follow-up (clinical investigation) for Indigenous and non-Indigenous women in Queensland after a high grade abnormality (HGA) being detected by Pap smear.

DESIGN, SETTING, PARTICIPANTS

Population-based retrospective cohort analysis of linked data from the Queensland Pap Smear Register (PSR), the Queensland Hospital Admitted Patient Data Collection, and the Queensland Cancer Registry. 34 980 women aged 20-68 years (including 1592 Indigenous women) with their first HGA Pap smear result recorded on the PSR (index smear) during 2000-2009 were included and followed to the end of 2010.

MAIN OUTCOME MEASURES

Time from the index smear to clinical investigation (histology test or cancer diagnosis date), censored at 12 months.

RESULTS

The proportion of women who had a clinical investigation within 2 months of a HGA finding was lower for Indigenous (34.1%; 95% CI, 31.8-36.4%) than for non-Indigenous women (46.5%; 95% CI, 46.0-47.0%; unadjusted incidence rate ratio [IRR], 0.65; 95% CI, 0.60-0.71). This difference remained after adjusting for place of residence, area-level disadvantage, and age group (adjusted IRR, 0.74; 95% CI, 0.68-0.81). However, Indigenous women who had not been followed up within 2 months were subsequently more likely to have a clinical investigation than non-Indigenous women (adjusted IRR for 2-4 month interval, 1.21; 95% CI, 1.08-1.36); by 6 months, a similar proportion of Indigenous (62.2%; 95% CI, 59.8-64.6%) and non-Indigenous women (62.8%; 95% CI, 62.2-63.3%) had been followed up.

CONCLUSIONS

Prompt follow-up after a HGA Pap smear finding needs to improve for Indigenous women. Nevertheless, slow follow-up is a smaller contributor to their higher cervical cancer incidence and mortality than their lower participation in cervical screening.