Developing a precise definition of frailty or an understanding of why it occurs remain areas of debate. Frailty is often defined by Fried’s criteria as unintentional weight loss, self-reported exhaustion, slow gait, weakness and low physical activity. A diagnosis of frailty requires three or more criteria to be present.  Some descriptions of frailty also include changes in mood, cognition, disability and the presence of multiple co-morbid illnesses. 
Frailty implies increased vulnerability to stressors, risk of multiple adverse health outcomes and decline in function. It is not clear whether this is accelerated ageing or due to a specific disease process.  Research has found increased risks associated with developing frailty.  These include:
- Shortened life expectancy
- Multiple co-morbid illnesses.
The last year of life is characterised by a steady decline in overall function, rather than a sudden decline in any one domain.  Frail older people may or may not have dementia. Frailty and dementia together predicts a more rapid decline and shorter life expectancy. Frailty is usually associated with being underweight. There is some evidence  that being overweight, particularly having increased abdominal fat, is associated with the same risks and disability as being frail.
Frail residents are seldom included in medication trials, but are vulnerable to over medication. It is important that medications are reviewed regularly and dosages individualised. 
Residents often have a slow decline in the months before death and sometimes lack a specific diagnosis. This means that caregivers and health professionals may not recognise that death is approaching and palliative care needs should be assessed.