Dementia Mortality: Estimates of survival after the onset of dementia range from 4 to 12 years

Sir,

Dementia is a progressive degenerative disorder of the brain leading to severe cognitive impairment, behavioural disturbances, and loss of functional ability to perform activities of daily living.[1] Systematic review of literature, have concluded that even mild levels of cognitive impairment gave rise to increased risk of mortality.[2] The risk of mortality seemed to be twice as high as in people not having dementia.[2] Pneumonia, cardiovascular disease, pulmonary embolus, and dementia were the underlying cause and never the direct cause of death.[3] A study on influence of type of dementia on mortality reported that the risk ratio was 2.0 (95% confidence interval 1.5–2.7) for Alzheimer's disease and 3.3 (95% confidence interval 2.0–5.3) for vascular dementia. The gender, age, pre-morbid physical conditions, severity of dementia and institutional accommodation seem to have a strong influence on the mortality pattern among patients with dementia.[4–6] This letter presents observation into the duration, physical co-morbidity, and mortality patterns among patients with dementia.

Vision Age India, a voluntary organization offers free home care service for patients with dementia; the patients are referred by psychiatrists and neurologists. All the patients had clinical diagnosis made by the respective consultant. The present report is based on an observation of mortality patterns observed in ten demised patients, over a period of six months, among the home care service users. The information was collected in a mortality performa developed for this purpose from the family members.

The patients were in the age group between 65 and 95 years (mean 74.20, median 74 and SD 8.24); there were four males and six females. Eight person had Alzheimer's disease, one person had vascular dementia, and one person had mixed type of vascular and Alzheimer's disease. It was found that the common causes of death among patients were myocardial infarction, pneumonia, lung infections, and undetected medical complications. The duration of dementia was less than four years in six patients, less than eight years in two patients, and twelve years in two patients. The family members were taking care of all the patients in their residence with part time nursing assistance. The co-morbid conditions were diabetes mellitus, hypertension, hip fracture, thyroid problems, stroke, and epilepsy.

The observations made in the mortality patterns in this study were within the range of one to twelve years reported in literature.[7–9] It was observed that females tend to suffer from various co-morbid conditions and also died before four years. The trend is against a study that reported the median survival from initial diagnosis as 4.2 years for men and 5.7 years for women with Alzheimer's disease.[10]

Six people out of ten dying due to cardiac complications is a clear indicator that physical health should be monitored in dementia patients to avoid premature mortality. Monitoring blood pressure and electrocardiogram once in three months can enable preventing cardiac fatalities.

Available literature on mortality is from western studies; the living circumstances and health services are very different. In the west, patients with dementia are likely to be in institutions, unlike in India where they are cared by the family members in their residence. So there is a need for studies with larger sample size to study the mortality patterns in India, among different age groups across different types of dementias. Such a study will enable us to identify the risk factors, the significance of co-morbid conditions, and psycho-social factors contributing to the mortality in dementia. Such data will provide guidance for medical speciality and care givers to be informed about the preventive measures to prevent premature mortality. It will also enable the care takers to take appropriate support services like respite care or hospice care.[10,11]