Engaging older patients in cardiovascular research: observational analysis of the ICON-1 study

Background: As a consequence of population ageing, the number of older patients presenting with acute coronary syndrome (ACS) is increasing. The historical underrepresentation of older patients in many pivotal ACS clinical trials undermines the practice of evidence-based medicine in this high-risk cohort. This study evaluates the feasibility of recruitment of older patients to a longitudinal, clinical study. Methods: The study to Improve Cardiovascular Outcomes in high-risk patieNts with ACS (ICON-1) is an observational, prospective cohort study investigating predictors of poor outcome in older patients with ACS. All patients aged >= 75 years, referred to a tertiary cardiovascular centre in the North East of England for coronary angiography with a view to urgent percutaneous coronary intervention, were screened for inclusion. A screening log was prospectively maintained, and a detailed analysis was performed to identify the factors associated with recruitment and non-recruitment to ICON-1. Results: Of the 629 patients screened over 34 months, 457 (72.7%) satisfied the a priori-defined study inclusion/exclusion criteria. Of those eligible to participate, 300 (68.5%) provided informed consent and were recruited to the study; 59 (13.5%) were unable to consent due to a lack of capacity or limitations in communication, and 79 patients (18.0%) declined to participate in the study. Those lacking adequate capacity to consent were older than those able to provide informed consent (83.0 +/- 4.7 vs 81.0 +/- 4.7 years, p=0.002). Women were more likely to decline than men (25.1% vs 10.0%, p<0.001). Conclusions: The recruitment of patients was robust, comparing favourably to previous longitudinal studies within this age group. Although enrolling older people to research remains challenging, this cohort is enthusiastic to participate. The contribution of older patients must not be ignored, particularly in the setting of an ever-ageing population, in whom cardiovascular disease burden is high.