Background: Mortality risk factors have attracted great research interest in recent years. Physical illness is strongly associated with mortality risk in elderly people. Furthermore, a relationship between mortality risk and psychiatric disease in the elderly has gained research interest.
Methods: This is a prospective longitudinal multicenter study. A sample of 324 participants was selected as a representative sample of community members aged 65 years and older and living in Huesca (Spain). The following information was collected: affiliation data, severity of physical illness, psychosocial, and psychiatric factors. Statistical analyses were completed with a multivariate analysis in order to control possible confounding variables related to mortality.
Results: Of the initially selected sample, 293 participants were assessed. Sixty-four participants died (21.8%, 95% CI [16.9%, 26.7%]), 5.3% annual rate, and 46.1% showed symptomatology of mental disorders. Older people have eight times greater risk of mortality. The risk increased 53 times in patients affected by several physical illness. No relationship between cognitive dysfunction and depressive symptomatology was observed. In fact, physical condition was associated with depression, and the percentage of participants with depressive symptoms increased according to the severity of physical illness.
Conclusions: Severity of physical illness and age are independently and directly associated with mortality in the elderly people. Therefore, severity of physical illness seems to be a crucial factor in the bi-directional association between mortality and depression, acting as a risk factor independently for both. So the relationship between depression and mortality can be affected by the severity of physical illness.