BACKGROUND: In December 2019, a new disease named coronavirus disease 2019 (COVID-19) was occurred . Patients who are critically ill with COVID-19 are more likely to die, especially elderly patients . We aimed to describe the effect of age on the clinical and immune characteristics of critically ill patients with COVID-19 .
METHODS: We retrospectively included 32 patients with COVID-19 who were confirmed to have COVID-19 by the local health authority and who were admitted to the first affiliated hospital of Zhengzhou University in Zhengzhou, China between January 3 and March 20 , 2020 . Clinical information and experimental test data were retrospectively collected for the patients . The 32 patients in this study were all in a critical condition and were classified as severe, according to the guidelines of 2019-nCoV infection from the National Health Commission of the People's Republic of China . Data were compared between those <60 years old and ≥60 years old .
RESULTS: Of 32 patients , 13 were under 60 years old, and 19 patients were ≥60 years old . The most common symptom among all patients upon admission was fever (93.8% , 30/32). Compared to younger patients, older patients exhibited increased comorbidities . Among patients who were 60 years and older, platelet count, direct bilirubin (DBIL), indirect bilirubin (IBIL), lactate dehydrogenase (LDH), B-type natriuretic peptide (BNP), C-reactive protein (CRP), procalcitonin (PCT), and interleukin-10 (IL-10) were significantly higher than in younger patients who were less than 60 years old . CD4+ T lymphocytes, CD8+ T lymphocytes, and NKT lymphocytes were decreased, CD4+/CD8+ T lymphocytes were significantly increased in all 32 patients, while there were no evident differences between younger and older patients . The CURB-65 (confusion, urea, respiratory, rate, blood pressure plus age ≥65 years), Acute Physiology and Chronic Health Evaluation (APACHE) II and pH value were significantly higher in older patients than in patients who were under 60 years old . However, the PaO2 and PaO2: FiO2 were lower in older patients than the younger . Compared to patients under 60 years old, patients who were 60 years and older tended to develop ARDS (15 [78.9 %] vs 5 [38.5 %] ), septic shock (7 [36.8 %] vs 0 [0.0 %] ) and were more likely to receive mechanical ventilation (13 [68.4 %] vs 3 [23.1 %] ). Dynamic trajectories of seven laboratory parameters were tracked on days 1 , 3 , 5 and 7, and significant differences in lymphocyte count (P = 0.026), D-dimer (P = 0.010), lactate dehydrogenase (P = 0.000) and C-reactive protein (P = 0.000) were observed between the two age groups .
CONCLUSIONS: A high proportion of critically ill patients were 60 or older . Furthermore, rapid disease progression was noted in elderly patients . Therefore, close monitoring and timely treatment should be performed in elderly COVID-19 patients.