Dementia: Prevalence, mortality rates, risk factors and management strategies

Dementia is a progressive global cognitive dysfunction resulting in cognitive and functional impairment. An accurate prognosis is helpful for the patient, family, healthcare professionals and also for planning of future health and social care resources. The incidence and prevalence of dementia is rising. Alzheimer's disease (AD) accounts for 60-80% of dementia cases, with vascular dementia (VaD) the next most common. There is also an increased mortality in patients with dementia with Lewy bodies and frontotemporal dementia. Median survival from time of onset of dementia is 3.3-11.7 years and from diagnosis is 3.2-6.6 years. There is an increased risk of death with dementia (hazard ratio (HR) 2-4) which can result from the disease itself, and comorbidities which may be associated with the disease process. Typical risk factors predicting outcomes in dementia, such as age of onset, gender and education, are often not supported by studies with varying outcomes. Increased mortality is associated with older age, but more life years will be lost in younger sufferers. Male gender is associated with a higher mortality (HR 1.2-1.9). Ethnicity and education do not have strong associations with mortality. People who carry the APOE e4 allele have an increased risk of developing AD (RR 3.2) and mortalityc doubles when AD is present. Reviewing the often heterogeneous study data on dementia makes comparisons difficult. Excess mortality in AD patients may be associated with the disease itself (adjusted HR 1.55 in AD versus non AD dementia). The common causes of death in dementia are cardiovascular, cerebrovascular and pneumonia. VaD patients have higher mortality from cardiovascular disease than AD. Current management is based around early diagnosis, support, education and the use of cholinesterase inhibitors and a NMDA receptor antagonist.