Quality of Life in Cardiovascular Disease: What is it and Why and How Should We Measure It?

One of the major goals of cardiovascular nursing should be the attainment of optimal health-related quality of life (HRQL) for patients and their families and carers. Cardiovascular diseases such as myocardial infarction and heart failure impose a substantial burden on quality of life [1], though this can be improved significantly by prevention [2], rehabilitation [3] and other disease management strategies [4]. Moreover, many patients with cardiovascular disease may have other chronic conditions which will have an even more negative effect on quality of life [5], and women are reported to have worse HRQL than men. [6] Thus, it is not surprising that there has been a significant growth in the measurement of HRQL as a prime indicator of health outcome and therapeutic benefit in patients with cardiovascular disease [7–13]. Indeed, this is reflected in recent papers in the European Journal of Cardiovascular Nursing [6,14–16]. However, there remains a lack of clarity as to what HRQL is and how best to measure it. HRQL refers to the impact that health conditions and their symptoms have on an individual's quality of life. HRQL serves as a common benchmark, against which can be measured, the impact of different experiences and treatments for the same condition or the impact of different treatments across different conditions. HRQL instruments have evolved in order to assess the impact of disease, effect of treatment and other variables affecting people's lives. Considering cardiovascular disease risk management is all about leading a healthy lifestyle, HRQL instruments are an optimal way of providing an assessment of the patient's experience of his or her health problems in areas such as physical, emotional or social function, role performance, and pain and fatigue. Furthermore, HRQL instruments can act as a proxy for health needs assessment in patients with cardiovascular disease [17]. HRQL instruments have been developed to measure: i) the effects of treatment on the outcome deemed to be of the greatest importance to the patient; and ii) what he or she has experienced as a result of illness and healthcare. The instrument selected should measure the health dimensions relevant to that particular patient cohort [18,19]. For instance, an instrument intended for use in a patient with heart failure should take into account the individual's responses to living with the disease, in terms of recreational, occupational, social, personal and sexual aspects, as well as the acute and chronic physical consequences of the disease [20]. HRQL instruments should to be comprehensive, reliable and valid, easy to score and interpret, and minimise respondent burden in order to quantify the impact and burden of disease. There are two types: ‘generic’ and ‘disease-specific’. The former are designed to address multiple aspects of HRQL across a range of different patient or disease groups [13] and include the Short-Form 36-item (SF-36) health survey [21] and the EuroQoL (EQ-5D) [22], whereas the latter measure the multiple aspects of HRQL relevant to a specific disease group and include the Seattle Angina Questionnaire (SAQ) [23], the MacNew [24], the MIDAS [25] and the Minnesota Living with Heart Failure (MLHF) questionnaire [26]. Overall, disease-specific instruments are more clinically sensitive and potentially more responsive in detecting change [27], though each type has its own particular strengths and weaknesses and there is established merit in using both [9]. However, selection should be guided by the psychometric properties of the instrument in question [28]. The real value of HRQL instruments is to show that changes are not just statistically significant but are also clinically meaningful [29,30].