# Comorbidities associated with a clinically-recognized delirium diagnosis in the hospital using real world data

## TL;DR

This study uses hospital records to find health conditions linked to delirium in older patients and shows delirium increases long-term death risk.

## Contribution

The study identifies sex-specific and longitudinal associations between comorbidities and delirium using real-world EHR data.

## Key findings

- Metabolic abnormalities and psychiatric diagnoses are significantly associated with inpatient delirium.
- Anemia and bipolar disorder show significant longitudinal associations with delirium development.
- Delirium diagnosis increases mortality risk independent of comorbidity burden.

## Abstract

Delirium is a mental condition defined as fluctuating disturbances in attention, awareness, and cognition. It is often seen in older, hospitalized patients and is currently hard to predict, with long- and short-term outcomes being detrimental to patients.

We leveraged electronic health records (EHR) to identify 7492 UCSF patients and 19,417 UC health system patients with an inpatient delirium diagnosis and the same number of control patients without delirium. We used the Fisher’s exact test with multiple corrections for the association studies and the Cox regression model for the longitudinal analyses.

Here we show significant associations between comorbidities or laboratory values and an inpatient delirium diagnosis, including metabolic abnormalities and psychiatric diagnoses. Some associations are sex-specific, including dementia subtypes and infections. We further explore the associations with anemia and bipolar disorder by conducting longitudinal analyses from the time of first diagnosis to development of delirium, demonstrating a significant relationship across time. Finally, we show that an inpatient delirium diagnosis leads to increased risk of mortality.

These results demonstrate the powerful application of the EHR to shed insights into prior diagnoses and laboratory values that could help predict development of inpatient delirium and the importance of sex when making these assessments.

Delirium is a serious and harmful condition characterized by a change in mental function compared to baseline, with symptoms often including confusion, impaired attention, and perceptual disturbances. It is a condition often seen in older, hospitalized patients and is currently hard to predict. Here we use data from medical records of patients diagnosed with delirium to better understand what other diagnoses are associated with delirium and show that one episode of delirium in the hospital can increase a patient’s risk of death long-term. These findings portray the detrimental outcome of delirium and emphasize the need for more awareness and research about the condition to find better ways to predict and prevent this condition in the hospital.

Kodama et al. use electronic health record data of patients with and without a delirium diagnosis to identify the comorbidities and laboratory values associated with inpatient delirium diagnoses. Longitudinal analysis also show that an inpatient delirium diagnosis is associated with an increased risk of mortality independent of comorbidity burden.