Could neutrophil-to-lymphocyte ratio predict mortality in community-dwelling older people with delirium superimposed on dementia?

BACKGROUND

Delirium superimposed on dementia (DSD) is associated with adverse outcomes in older adults. Nonetheless, little is known about the association between inflammatory markers and clinical outcomes of DSD.

AIMS

This research investigated the predictive value of the neutrophil-to-lymphocyte ratio (NLR) for short- and long-term mortality among community-dwelling older adults with DSD.

METHODS

This retrospective cohort study included 9755 older outpatients who were referred to a tertiary hospital between January 2010 and June 2021. All patients underwent a comprehensive geriatric assessment and routine laboratory tests. Delirium and dementia was diagnosed with the DSM-4 or DSM-5 criteria. We recorded information on mortality during 1 year following the delirium episode.

RESULTS

Among 615 patients with dementia, 170 (26.3%) had delirium. Patients with delirium were predominantly older, with higher Deyo-Charlson comorbidity index scores, lower general cognitive performance, lower functional capability, and higher anticholinergic burden compared to those without delirium. At the 1-year follow-up, the mortality rate of DSD was 29.3%. Multivariate analysis showed that NLR at admission was an independent predictor of 1-month mortality (HR = 1.03; 95% CI 1.00-1.05; p = 0.04) and 1-year mortality (HR = 1.02; 95% CI 1.01-1.05; p = 0.01) of DSD patients.

DISCUSSION

NLR can predict prognosis in various diseases including cardiovascular disease, malignancies, and cerebrovascular disease, but as yet there is no similar prognostic measure in delirium. Moreover, recent previous studies demonstrated NLR is a potential marker for the prediction of delirium in older adults with different clinical settings. In the current study, we demonstrated that NLR is also a prognostic marker for DSD.

CONCLUSIONS

NLR could be useful marker for predicting short- and long-term mortality in patients with DSD. However, further studies are needed to validate these findings.