Delirium is associated with poor outcomes and high mortality. Current research shows conflicting results regarding mortality rates in patients with delirium.

The aim was to examine the hazard risk associated with delirium in elderly medically ill patients at 1 year follow-up, controlling for baseline risk factors and interaction effects.

This was a prospective, observational, longitudinal study carried out in the medical wards of Sligo Regional Hospital. All acute medical admissions of patients 70 years old and over were approached. Each patient was assessed twice weekly for 2 weeks or until discharge. The following scales were used: CAM, DRS-98R, MoCA, Barthel Index, APACHE II. Primary outcome was time of death during 1 year. Cox proportional hazards were estimated and compared across patients who had delirium during hospitalisation and those who did not.

Two hundred patients agreed to take part in the study. The mean age of the studied sample was 81.13 (SD = 6.45; minimum 70 and maximum 100 years old) with 100 (50%) females. One hundred fifty four (77%) patients never developed delirium during hospitalization. Thirty four (17%) had delirium at admission and 12 (6%) developed prevalence delirium while inpatients. A total of 55 (27.5%) patients died during the one year follow-up. Significant risk factors for 1 year mortality were length of hospital staying, severity of illness (APACHE II), and cognition (MoCA).

Delirium was not found as an independent risk factor for 1 year mortality after controlling for other confounder variables.