These findings provide new insights into the early months of the pandemic and will help to inform the ongoing response, such as vaccination strategies.
Using data from over 5.5 million individuals, representing around 80% of the population of Catalonia, the study identified 102,002 patients who had an outpatient diagnosis of COVID-19, 16,901 who were hospitalised with COVID-19, and 5,273 who died after either being diagnosed or hospitalised with COVID-19 between 1st March and 6th May 2020.
On examining the characteristics of those with COVID-19, older age was the factor most strongly associated with worse outcomes (hospitalisations and deaths). Of the COVID-19 deaths observed, more than 80% were among individuals aged 70 or older. While COVID-19 deaths were concentrated among those at oldest ages, hospitalisations were less so. In fact, close to 40% of those hospitalised after an outpatient diagnosis of COVID-19 were aged between 40 and 59. Males were also seen to be at an increased risk of worse outcomes, making up 60% of deaths. Comorbidities were also associated with worse outcomes, although after adjusting for age and sex their impact were generally most pronounced among younger patients.