Experiences of a National Web-Based Heart Age Calculator for Cardiovascular Disease Prevention: User Characteristics, Heart Age Results, and Behavior Change Survey

Abstract

Background Heart age calculators are used worldwide to engage the public in cardiovascular disease (CVD) prevention. Experimental studies with small samples have found mixed effects of these tools, and previous reports of population samples that used web-based heart age tools have not evaluated psychological and behavioral outcomes. Objective This study aims to report on national users of the Australian heart age calculator and the follow-up of a sample of users. Methods The heart age calculator was launched in 2019 by the National Heart Foundation of Australia. Heart age results were calculated for all users and recorded for those who signed up for a heart age report and an email follow-up over 10 weeks, after which a survey was conducted. CVD risk factors, heart age results, and psychological and behavioral questions were analyzed using descriptive statistics and chi-square tests. Open responses were thematically coded. Results There were 361,044 anonymous users over 5 months, of which 30,279 signed up to receive a heart age report and 1303 completed the survey. There were more women (19,840/30,279, 65.52%), with an average age of 55.67 (SD 11.43) years, and most users knew blood pressure levels (20,279/30,279, 66.97%) but not cholesterol levels (12,267/30,279, 40.51%). The average heart age result was 4.61 (SD 4.71) years older than the current age, including (23,840/30,279, 78.73%) with an older heart age. For the survey, most users recalled their heart age category (892/1303, 68.46%), and many reported lifestyle improvements (diet 821/1303, 63.01% and physical activity 809/1303, 62.09%). People with an older heart age result were more likely to report a doctor visit (538/1055, 51.00%). Participants indicated strong emotional responses to heart age, both positive and negative. Conclusions Most Australian users received an older heart age as per international and UK heart age tools. Heart age reports with follow-up over 10 weeks prompted strong emotional responses, high recall rates, and self-reported lifestyle changes and clinical checks for more than half of the survey respondents. These findings are based on a more engaged user sample than previous research, who were more likely to know blood pressure and cholesterol values. Further research is needed to determine which aspects are most effective in initiating and maintaining lifestyle changes. The results confirm high public interest in heart age tools, but additional support is needed to help users understand the results and take appropriate action.

Current Best Practice for Presenting Probabilities in Patient Decision Aids: Fundamental Principles

“…Heart age calculators can work well as a marketing tool to get attention and direct consumers to appropriate clinical assessments or lifestyle change, 93 but caution is needed to ensure they are not used to nudge low-risk people toward medications and tests that they are unlikely to benefit from in the short term. 94 A registered trial (ACTRN12620000806965) will soon test the effect of adding heart age to a cardiovascular disease prevention decision aid for the first time, to investigate how it affects decision making.…”

The impact of health literacy-sensitive design and heart age in a cardiovascular disease prevention decision aid: randomised controlled trial and end user testing

“…Firstly, amongst those who were shown their heart age, gist knowledge of percentage risk was initially improved, but after 4 weeks gist and verbatim knowledge were higher for heart age than for percentage risk. Previous studies have shown that people receiving an older heart age may react defensively and focus on other information, such as a low short-term risk level, which in turn may reduce credibility of the risk result 24,58 . Analyses of people who received an older heart age result suggests it may be useful as a marketing tool to get attention and initiate behaviour change, but knowledge of heart age did not translate to knowledge of risk.…”

“…In considering how to power such trials, researchers will need to consider how the specific heart age tool they are using is calibrated for the intended population (e.g. ∼50% older in our sample using NZ method versus ∼80% in Australian/UK HF tool 23,24 ). The primary outcome also needs to carefully considered.…”

“…Some countries have used online CVD risk assessment tools for absolute risk and heart age to engage consumers in CVD prevention, with millions of users worldwide 21–24 . However, our systematic review of 73 online CVD risk assessment tools available to consumers found they were not suitable for people with lower health literacy: their readability level was too high; they frequently used unexplained medical terms; few used best practice risk communication formats such as frequencies in icon arrays; and they rated poorly on actionability (i.e.…”

“…This project aimed to develop and test a new consumer engagement tool for CVD prevention based on the above strategies, to address the needs of Australians with different levels of health literacy. It builds on our previous development of a GP-focused risk calculator and decision aid 36 , and evaluation of the national heart age calculator 24 .…”