Effects of numerical information on intention to participate in cervical screening among women offered HPV vaccination: a randomised study

Abstract

Objectives: To investigate the effects of different types of information about benefits and harms of cervical screening on intention to participate in screening among women in the first cohorts offered human papilloma virus (HPV) vaccination.

Design: Randomised survey study.

Setting: Denmark.

Subjects: A random sample of women from the birth cohorts 1993, 1994 and 1995 drawn from the general population.

Interventions: A web-based questionnaire and information intervention. We randomised potential respondents to one of the following four different information modules about benefits and harms of cervical screening: no information; non-numerical information; and two numerical information modules. Moreover, we provided HPV-vaccinated women in one of the arms with numerical information about benefits and harms in two steps: firstly, information without consideration of HPV vaccination and subsequently information conditional on HPV vaccination.

Main outcome measure: Self-reported intention to participate in cervical screening.

Results: A significantly lower proportion intended to participate in screening in the two groups of women receiving numerical information compared to controls with absolute differences of 10.5 (95% CI: 3.3–17.6) and 7.7 (95% CI: 0.4–14.9) percentage points, respectively. Among HPV-vaccinated women, we found a significantly lower intention to participate in screening after numerical information specific to vaccinated women (OR of 0.38).

Conclusions: Women are sensitive to numerical information about the benefits and harms of cervical screening. Specifically, our results suggest that HPV-vaccinated women are sensitive to information about the expected changes in benefits and harms of cervical screening after implementation of HPV vaccination.

KEY POINTS

• Women were less likely to participate in cervical screening when they received numerical information about benefits and harms compared to non-numerical or no information.

• Specifically, numerical information about the potential impact of the reduced risk of cervical cancer among HPV-vaccinated women reduced the intention to participate among vaccinated women.

Keywords:

• Cervical screening
• HPV vaccination
• medical prevention
• cancer screening
• informed choice
• medical decision-making
• general practice
• Denmark

Acknowledgements

The authors would like to thank Professor Kirsten McCaffery and Ms Jolyn Hersch, PhD for valuable discussions and input for this paper. Furthermore, Ms Brooke Nickel, BSc, MPH for correcting the translation of the questionnaire. The authors affirm that they have listed everyone who contributed significantly to the work in this section.

Disclosure statement

The authors have no financial relationships (personal or institutional) that could be viewed as presenting a potential conflict of interest or that might otherwise bias this work.

Funding

Financial support for this study was provided in part by grants from Helsefonden and The Danish Cancer Society. The funding agreements ensured the authors’ independence in designing the study, interpreting the data, writing, and publishing the report.

Ethics and consent

According to Danish legislation, notification to the Danish Data Protection Agency serves as ethical approval of register-based research and survey projects without a clinical intervention. This includes the data-linkage with Statistics Denmark conducted in this study. Anonymity was assured by automatically generated ID-numbers, and thus, consent from participants was not needed. This project has notification number 2014-41-3545.