Comorbidity and its effect on mortality in nursing home patients with dementia

The relation between comorbidity and survival was investigated in an 8-year follow-up study of 606 nursing home dementia patients by means of proportional hazards analysis. Two-year survival rates for women (N = 437) and men (N = 169) were 60% and 39%, respectively. Parkinsonism, atrial fibrillation, pulmonary infection, and malignancies were powerful predictors: they more or less doubled the mortality chances. Stroke patients with a pulmonary infection had a particularly poor prognosis. More severely demented patients had more comorbidity than less severely demented patients, but the impact of comorbidity on survival did not depend on severity of dementia. Patients coming from a hospital had more comorbidity and were more severely demented than patients coming from home, but this did not modify the effects of age, gender and comorbidity in a multivariate survival model. It was concluded that comorbidity and severity of dementia independently influence mortality. Thus a better prognostic judgment is obtained from their combination than from each separately.