JMIR Publications

ABSTRACT

Background:

Cardiovascular disease (CVD) risk communication is a challenge for clinical practice, where doctors find it difficult to explain the absolute risk of a CVD event to patients with varying health literacy. Converting the probability to ‘heart age’ is increasingly used to promote lifestyle change in a more intuitive way, but a rapid review of biological age interventions found no clear evidence that they motivate behaviour change.

Objective:

We aimed to identify the content and effects of heart age interventions in more detail to better understand this finding.

Methods:

Systematic review of quantitative and qualitative studies presenting heart age interventions to adults for the purpose of CVD risk communication. The review was conducted in April 2020, and updated in March 2021. The Johanna Briggs risk of bias assessment tool was applied to randomised studies. Behaviour change techniques described in the intervention methods were coded using Michie et al.’s taxonomy.

Results:

From 7,926 results, 16 eligible studies were identified: 5 randomised online experiments, 5 randomised clinical trials, 2 mixed methods studies with quantitative outcomes and 4 with qualitative analysis. Direct comparisons between heart age and absolute risk in 5 online experiments included 5,514 consumers and found that heart age: increased positive/negative emotional responses (4/5 studies), risk perception (4/5 studies; but not necessarily more accurate) and recall (4/4 studies), reduced credibility (2/3 studies), and generally had no effect on lifestyle intentions (4/5 studies). One study compared heart age and absolute risk to fitness age, and found reduced lifestyle intentions for fitness age. When heart age was combined with additional strategies (e.g. in person/phone counselling) in applied settings for 9,582 patients, it improved risk control (e.g. reduced cholesterol and absolute risk) compared to usual care in most trials (4/5 studies) up to 1 year. However, clinical outcomes were no different when directly compared to absolute risk (1/1 study). Mixed methods studies echoed the outcomes in the randomised trials, but also identified consultation time and content as an important outcome, as well as differences between receiving an older heart age versus young/equal to current age. The heart age interventions described in these studies included a wide range of behaviour change techniques, and conclusions were sometimes biased in favour of heart age with insufficient supporting evidence. Risk of bias assessment indicated issues with all randomised trials.

Conclusions:

This review found little evidence that heart age motivates lifestyle behaviour change more than absolute risk, but either format can improve clinical outcomes when combined with other behaviour change strategies. The label for the “heart age” concept can affect outcomes and should be pre-tested with the intended audience. Future research should consider consultation time and differentiate between older and younger heart age results.