Predictors of adverse outcomes in aged patients critically ill with COVID-19: a retrospective study

Older patients represent an inordinate proportion of intensive care unit (ICU) admissions and ICU mortality associated with coronavirus disease 2019 (COVID-19). In this retrospective cohort study, we examine 198 patients, aged 18 years or older, admitted to the ICU from March to June 2020. We aim to understand the relationships between age, number of comorbidities, and independent living prior to admission on outcomes of mortality, length of stay, renal failure, respiratory failure, and shock. In this cohort, we find that overall mortality was associated with respiratory failure severity (for every decrease of P:F by 50, odds ratio (OR) 2.98 (1.65-6.08)), acute renal failure (OR 4.61 (1.2-19.7)), and age 65 or greater (OR: 3.7 (1.86-7.36)). Surprisingly, increasing age was associated with less severe respiratory failure (R = 0.22, p < 0.01). When adjusting for pre-existing chronic kidney disease, age was not associated with development of acute kidney injury (OR: 1.01 (0.99-1.03)). While chronologic age is associated with mortality, it is not associated independently with severe end organ damage. This is consistent with growing evidence suggesting that a complex interplay between multimorbidity, immunosenescence, and physiologic age is primarily responsible for the vulnerability to COVID-19.