Hospital outcomes for older people with cognitive impairment and dementia

Older people with a diagnosis of dementia are at higher risk of poor outcomes following a hospital admission, such as death and longer lengths of stay. It is not known whether older people with other causes of cognitive impairment are at a similar risk, whether dementia or other cognitive impairments are independent risk factors, and whether staffing levels may differentially influence outcomes. This work is based on a secondary care dataset of more than 20,000 hospital admissions. The characteristics of older people with acute hospital admissions and their outcomes according to the presence of dementia/cognitive impairment are described, and the associations between dementia/cognitive impairment and mortality, length of stay and readmission investigated. The clinical dataset was linked to data on nurse staffing to understand how varying staffing levels influence mortality and readmission in people with any cause of cognitive impairment. Cognitive impairment was found to be prevalent in the older hospital population. Patients with cognitive impairment but no diagnosis of dementia had a similar risk of dying in hospital and longer lengths of stay as compared to patients with an existing diagnosis of dementia. There was an independent association between cognitive impairment (with or without a diagnosis of dementia) and higher hospital mortality, longer hospital stays and higher readmissions to hospital after controlling for other significant risk factors. Nurse staffing time per patient above mean values significantly decreased mortality for all patients, with a greater effect for patients with cognitive impairment, as well as reducing readmissions in this group. Increased nursing assistant hours improved mortality rates in patients with cognitive impairment but were significantly associated with increased mortality in cognitively intact patients. The thesis includes two articles which establish a vulnerable clinical population in hospital and provide estimates of associations with poor outcomes, and a further article which highlights staffing levels as a consideration for modifying care for this patient group. The results provide evidence that although older people with cognitive impairment are at higher risk from worse hospital outcomes, this risk may be modified by appropriate provision of nursing workforce. Further work is required to understand the mechanisms of risk reduction with higher staffing levels for older hospitalised patients with cognitive impairment.