The impact of a personalised blood pressure warning on health behaviour

Background

There is evidence that people do not recognize the existence or severity of chronic disease conditions, many of which are asymptomatic. This is important because, if they did, we may expect behavioural responses to control the condition and mitigate its impact on their lives, with direct implications for their welfare and positive externalities for the National Health Service (NHS). Information campaigns advising raised fruit and vegetable consumption or reduced salt intake and smoking are increasingly used but have had mixed success and it seems plausible that this is because individual’s do not personalize risks presented in population-level terms. Psychologists refer to this as “illusory superiority” – that people judge themselves superior on personality traits to an average peer.

Against this backdrop, we investigate the extent to which individual-specific clinical information on health status results in behavioural change. We use the UK Longitudinal Household Survey data which are rich in information on individual characteristics, behaviours and outcomes, and that recently incorporated nurse visits following which respondents were given clinical information on a number of biomarkers including blood pressure. We focus upon hypertension which is (a) highly prevalent, (b) a risk factor for chronic diseases and (c) asymptomatic and hence often undiagnosed. Hypertension (high blood pressure) is a leading risk factor for coronary heart disease (leading cause of death in the UK and worldwide), stroke (2nd leading cause of death in the UK and worldwide), chronic kidney disease, and aneurysm, for instance. Worldwide it accounts for 9.4 million deaths every year with the World Health Organisation (WHO) calling it a global public health issue (WHO (2013)).

Project aims

We investigate how individuals use clinical information on their health to modify their behaviours. We will estimate the impact of these responses on health outcomes. In contrast to previous research we will provide quantitative evidence on a condition which is (a) less severe (in terms of reduced life expectancy and quality of life) but very widespread in the developed and developing world, (b) can be controlled with medication and lifestyle choices (diet, exercise, alcohol consumption, weight, smoking; and (c) is asymptomatic – even at high levels – meaning that our results may be interpreted as stemming from an information effect and are unlikely to suffer confounding with direct debilitating effects of the disease that for instance may prevent individuals working full-time.