A Vicious Cycle of Heart Failure and Dementia
The end of life is not pretty. The body is a failing machine of many complex essential parts, and the failures cascade and feed into one another as it breaks down. There is pain, loss of capacity, loss of the self as the brain runs down. There is a tendency to paper over the ugly reality in public discussion, to not talk about the facts of the matter, even when we all know people who have suffered a slow and painful decline. That the slow progression towards death by aging is an ugly reality, a horrible experience in its final stages, just adds to the reasons why far more effort should go towards the development of rejuvenation therapies capable of preventing the age-related failure of our bodies and brains.
The prevalence of heart failure is increasing in aging populations. Furthermore, dementia is more prevalent in patients with heart failure. Dementia is detected 10 years earlier in patients with heart failure in Asian countries, particularly low-income countries, than in Western countries. Heart failure and dementia share similar cardiovascular risk factors, such as age, hypertension, diabetes, dyslipidemia, and increased arterial stiffness, which explains their overlap in elderly patients.
In a large database of patients with heart failure (mean age 75.3 years), 11.0% developed dementia during an average follow-up period of 4.1 years. Heart failure patients with dementia were at a 4.5-fold higher risk of all-cause mortality, 5.4-fold higher risk of cardiovascular death, and 3.8-fold higher risk of noncardiovascular death. An analysis of a longitudinal dataset indicated a causal relationship between decreased cardiac function and cognitive decline.
Heart failure patients with dementia often have sarcopenia and cachexia. Nutritional changes caused by hypoperfusion and edema in skeletal muscles, the intestines, and visceral organs may contribute to the risk of cardiovascular and noncardiovascular mortality. Autonomic nerve dysregulation has been detected in some patients with dementia, particularly those with Lewy body disease. Elderly patients with heart failure are also more susceptible to infections owing to a decreased lymphocyte count.
Heart failure patients that develop dementia enter a vicious cycle of heart failure, dementia, malnutrition, sarcopenia, and cachexia, which is associated with an increased risk of all-cause mortality. Therefore, the prevention of cognitive decline is important in elderly patients with heart failure.