# Exploring the differences in mortality and its associated factors among young-old and old-old COVID-19 patients

## TL;DR

This study finds that older elderly patients with COVID-19 have higher mortality and unique risk factors compared to younger elderly patients.

## Contribution

Identifies unique risk factors for mortality in old-old (≥75 years) versus young-old (65–74 years) COVID-19 patients.

## Key findings

- Old-old patients had significantly higher mortality (31.3%) compared to young-old patients (12.7%).
- Dyspnea, acute cardiac injury, diabetes, and glucocorticoid therapy were unique risk factors for mortality in old-old patients.
- Survival curves differed significantly between the two age groups, but no sex differences were observed.

## Abstract

This study aims to compare the differences in mortality and related factors between old-old and young-old COVID-19 patients and find unique factors related to survival in old-old patients.

Single-center retrospective cohort study following STROBE guidelines.

We included 302 elderly (≥65 years old) COVID-19 patients admitted to Shijiazhuang People’s Hospital from December 1, 2022 to March 31, 2023. Among them, 142 were assigned to the young-old group (65–74 years old) and 160 in the old-old group (≥75 years old). Demographic, clinical and laboratory data were extracted, and descriptive statistical analysis, comparison of differences between groups, Cox proportional hazards regression analysis, and subgroup analysis were adopted.

Compared with the young-old group, the mortality of old-old patients was higher (31.3% vs. 12.7%, p < 0.001). Risk factors associated with mortality specifically in old-old patients include dyspnea (HR: 2.829, 95%CI: 1.571–5.093), acute cardiac injury (HR: 2.403, 95%CI: 1.369–4.219), and diabetes (HR: 2.401, 95%CI: 1.311–4.397), glucocorticoid therapy (HR: 2.397, 95%CI: 1.198–4.798). Moreover, there was a significant difference in the survival curves between the young-old and the old-old group (p = 0.0001). However, no significant sex differences in mortality and survival curves were found in either group.

This study found for the first time that dyspnea symptoms, acute heart injury, diabetes, and glucocorticoid therapy are unique risk factors related to survival in old-old patients with COVID-19. These factors need more attention when treating old-old patients to prevent poor prognosis.