Brain and heart disease represent a major health burden in Canada and often occur together in the same patient. The CARDIACDOC prospective cohort study, led by Dr. Jodi Edwards, investigates the link between heart failure and neurological co-morbidities, including Depression, Obstructive sleep apnea, and Cognitive impairment (DOC). By incorporating both the heart and brain systems, this study aims to better identify heart failure patients with neurological conditions that may affect their ability to manage their disease. The results will ultimately serve to improve treatment and patients’ quality of life, while demonstrating how integrated brain-heart research can shape the future of heart failure care.
Highlighting Brain-Heart Research During Heart Month
February is Heart Month in Canada, a time to raise awareness, education, and advocacy around heart and cardiovascular health. At the BHI, we believe better heart health comes from an integrated approach that looks at the body not as separate systems, but as a collection of deeply connected pathways. The brain and heart are in constant communication, with many important points of overlap and influence between the two. Together, brain and heart diseases account for the greatest burden, highest mortality, and economic cost of disease in Canada, and many of these conditions frequently co-exist in the same individual (1–3). This highlights that addressing heart health and improving treatment requires studying the brain and heart together; to overcome heart disease, we must look beyond the heart.
Heart failure is a complex condition caused by structural or functional abnormalities of the heart that reduce its ability to pump blood effectively. It affects hundreds of thousands of Canadians each year and is associated with significant long-term health complications and increased risk of mortality. A major challenge of heart failure treatment is that these patients have complicated care routines, with many medications and lifestyle factors to manage. Furthermore, cognitive and depressive symptoms are common among heart failure patients, making it difficult for many to properly maintain recommended routines.
A BHI-driven project, the CARDIACDOC prospective cohort study, addresses this knowledge gap in heart failure care by examining the brain-heart connection. Using a unique screening tool, the study examines the prevalence of neurological symptoms in heart failure patients to help physicians identify patients who require additional support to manage their heart disease. This study is led by Co-Leads Dr. Jodi Edwards at the University of Ottawa Heart Institute (UOHI) and Dr. Rick Swartz at Sunnybrook Research Institute, alongside a team including Dr. Doug Lee (University of Toronto), Lauren Pattison, Dr. Lisa Mielniczuk, Dr. Peter Liu, and Dr. Sharon Chih (UOHI).
“Heart failure patients are some of the most medically complex heart disease patients that are very vulnerable to brain conditions and are an important population for heart brain research,” Dr. Edwards highlights.
By focusing on both the heart and the brain, CARDIACDOC expands the scope of heart failure care beyond heart function alone, aiming to inform integrated care and improve treatment outcomes and quality of life for patients.
Understanding Neurological Co-Morbidities in Heart Failure
The research team, made up of epidemiologists, scientists, and clinicians, observed that heart failure patients often have non-cardiovascular, neurological co-morbidities. Comorbidities refer to multiple health conditions that can occur in the same person. Among the most common neurological co-morbidities in heart failure are depression, obstructive sleep apnea, and cognitive impairment, collectively called ‘DOC.’ These conditions are frequently overlooked, underdiagnosed, and untreated in patients, despite their potential to have a major impact on patients’ health. CARDIACDOC studies both cardiovascular and neurological symptoms—and the connection between the two—to better understand heart failure and guide ways to treat it.
The objectives of this study are two-fold: first, to test the feasibility of integrating a brief (six minutes or less) DOC screen within the heart failure clinic workflow to validate a tool that can be used in regular clinical care; and second, to measure the risk levels (low, intermediate, and high) for depression, obstructive sleep apnea, and cognitive impairment in these patients (4). The DOC screen, designed by Dr. Swartz’s team, is widely available and has previously been validated in stroke populations. Once these results are collected, the study will use statistical modeling to determine whether DOC scores can predict future adverse outcomes in heart failure patients, including mortality and hospital re-admissions. If successful, this brief screening tool will have a profound positive impact on health failure patients by enabling earlier intervention, improving patient quality of life, and reducing the burden of heart failure on the healthcare system.
Early Findings from the CARDIACDOC Study
The team recently presented these findings at the 2025 Canadian Cardiovascular Congress (CCC), reporting that 203patients with advanced heart failure have been recruited and screened for DOC at the UOHI Heart Failure clinic to date. Importantly, 97.5% of patients were screened in under six minutes, demonstrating successful feasibility of the tool. Regarding risk levels, 11% of patients were at high risk for depression, 4% for obstructive sleep apnea, and 17% for cognitive impairment. Overall, the risk of depression was low, with 48% of patients having a risk score of 0. In contrast, 95% of patients were at intermediate or high risk for cognitive impairment. This highlights the need to treat not only heart failure symptoms, but also cognitive impairment, supporting a more comprehensive approach to patient care.
Dr. Edwards explains: “By identifying patients at cognitive risk, we can develop tailored support programs for these patients to help them better manage their heart disease and improve their heart and brain outcomes.”
Improving Heart Health for All
Dr. Edwards and her team have shown that integrating the DOC assessment into the clinic is simple, fast, and feasible. The next step of the project will use patients’ medical information along with data analysis and predictive modeling to determine whether early identification of DOC can predict future health risks related to heart failure. This means that a brief, easy screening during a regular clinic visit could significantly improve quality of life for heart failure patients, ideally reducing hospital readmissions and improving long-term outcomes. CARDIACDOC is a foundational study supported by the BHI, demonstrating that research to improve heart health benefits from looking beyond the heart alone and considering the critically connected brain. The study points to an optimized future for heart failure care in which mental, neurological, and cardiac health are not only studied together but also treated together.
References
- Global Health Estimates: Life expectancy and leading causes of death and disability [Internet]. World Health Organization. 2019. Available from: https://www.who.int/data/gho/data/themes/mortality-and-global-health-estimates
- Roth GA, Mensah GA, Johnson CO, Addolorato G, Ammirati E, Baddour LM, et al. Global Burden of Cardiovascular Diseases and Risk Factors, 1990–2019. Journal of the American College of Cardiology. 2020 Dec;76(25):2982–3021.
- Report 2019 [Internet]. Heart and Stroke Foundation of Canada. Available from: https://www.heartandstroke.ca/articles/report-2019
- Pattison L, Dee D, Mielniczuk L, Liu P, Southwell A, Sujanthan S, et al. P171 SCREENING FOR DEPRESSION, OBSTRUCTIVE SLEEP APNEA, AND COGNITIVE IMPAIRMENT TO PREDICT ADVERSE OUTCOMES IN HEART FAILURE PATIENTS: THE CARDIACDOC PROSPECTIVE COHORT STUDY. Canadian Journal of Cardiology. 2025 Oct;41(10):S105.