Predictors of COVID‑19‑associated mortality among hospitalized elderly patients with dementia

The mortality of elderly patients with dementia hospitalized with coronavirus disease 2019 (COVID-19)-associated pneumonia is high. The mortality rate of these patients continues to be high following their discharge. However, data on the outcomes of these patients in all phases of the pandemic are limited. The aim of the present study was to examine the clinical characteristics and the in-hospital and 90-day mortality rates of elderly patients with dementia hospitalized due to COVID-19-associated pneumonia during all phases of the pandemic. During the time period between February 15, 2021 to July 15, 2022, 105 elderly patients (≥65 years old) with dementia of various etiologies were hospitalized due to COVID-19-associated pneumonia. The patient characteristics and in-hospital outcomes within 90 days of admission were recorded. The mean age of the patients was 84.03±7.61 years and 60 (57.1%) patients were females. A total of 52 (49.5%) patients were hospitalized during the omicron variant period, 27 (25.7%) were fully vaccinated (three doses) and 38 (36.2%) patients succumbed during their hospitalization. In total, 52 (49.5%) patients succumbed within the first 90 days of admission. According to the univariate regression analysis, the omicron variant [hazard ratio (HR), 2.126; 95% confidence interval (CI), 1.073-4.213; P=0.031] and the absence of full vaccination (HR, 6.231; 95% CI, 1.500-25.87; P=0.012) were associated with a higher in-hospital mortality. In the multivariate regression analysis, only the absence of complete vaccination was an independent predictor of mortality (HR, 5.182; 95% CI, 1.205-22.28; P=0.027). According to the univariate regression analysis, age (HR, 1.045; 95% CI, 1.006-1.085; P=0.023) and the lack of complete vaccination (HR, 3.254; 95% CI, 1.294-8.181; P=0.012) were associated with 90-day mortality; in addition, by multivariate regression analysis, age (HR, 1.047; 95% CI, 1.007-1.048; P=0.021) and the absence of full vaccination (HR, 3.286; 95% CI, 1.307-8.265; P=0.011) exhibited an independent association with the 90-day mortality rate. Based on the findings presented herein, the in-hospital and 90-day mortality rates of elderly patients with dementia and COVID-19-associated pneumonia is high. An older age and the lack of complete vaccination are independently associated with poor outcomes.