COVID-19 as an effect modifier of the relationship between age and in-hospital survival in older patients admitted to an Italian Emergency Department.

Background: The SARS-CoV-2 pandemic modified how persons got into contact with emergency services, particularly during the first wave.

Aim: The aim is to describe the characteristics of older persons with and without COVID-19 visiting the Emergency Department of a tertiary hospital and to investigate the impact of age on in-hospital survival in the two groups.

Methods: Patients older than 70 years were followed-up till discharge or in-hospital death. Cox regression models stratified by COVID-19 diagnosis were used to investigate survival.

Results: Out of 896 patients, 36.7% had COVID-19. Those without COVID-19 were older and affected by a higher number of chronic conditions but exhibited lower mortality (10.5 vs 48.1%). After the adjustment, age was associated with mortality only among those with COVID-19.

Discussion: COVID-19 modified the relationship between older age and in-hospital survival: whether this finding is explained by other biological vulnerabilities or by a selection of treatments based on age should be further investigated.