Risk Factors for Mortality in 244 Older Adults With COVID-19 in Wuhan, China

A Retrospective Study

Haiying Sun, MD; Ruoqi Ning, MD; Yu Tao, MD; Chong Yu, MD; Xiaoyan Deng, MD; Caili Zhao, MM; Silu Meng, MM; Fangxu Tang, MD; Dong Xu, MD, PhD

Disclosures

J Am Geriatr Soc. 2020;68(6):E19-E23. 

In This Article

Discussion

This retrospective study identified risk factors for death in hospitalized older patients with COVID-19. Older age and lower LYM count were independent risk factors for death among older patients. In addition, higher WBC count may also be related to poorer prognosis.

Many studies have reported that age is an important risk factor for respiratory diseases.[8–10] Moreover, immunosenescence has been identified as a major cause of high mortality due to severe pneumonia in older adults.[8] Humoral and cellular immune functions decline with age. Immunoglobulin M and interferon levels decrease, the number of T cells decreases, cell division and proliferation decrease, neutrophils exhibit decreased chemotaxis, and phagocytosis also decreases with age.[11] When a virus invades the body, it activates the immune system. Thus, for older patients with fewer T cells, the probability of death increases. Results of this study revealed that WBC count was higher among deceased patients than those who were discharged. A previous study reported that a decline in host immunity after viral infection may lead to secondary or bacterial infection.[12]

A recent study[13] identified risk factors for death in adults who were hospitalized with COVID-19 in Wuhan and found that older age, D-dimer levels greater than1 μg/mL, and higher Sequential Organ Failure Assessment score on admission increased the risk for death. Additionally, severely ill patients with COVID-19 had elevated blood levels of IL-6, hs-TnI, and lactate dehydrogenase, and lymphopenia. However, D-dimer levels demonstrated no statistical difference among older patients in our study (P = .401) and may be more predictive among younger patients. Due to the absence of data, IL-6 could not be included in the logistic regression analysis.

Fever and dry cough were the most common symptoms in patients with COVID-19. Moreover, gastrointestinal symptoms were experienced by 33.2% of the patients in our study. For older patients with coronary heart disease and diabetes, mortality may not increase if complications are well controlled. Patients with hypertension also exhibited poorer outcomes (P = .042). A recent study reported that angiotensin-converting enzyme 2 (ACE2) may be the host receptor for SARS CoV-2.[14] Many models of hypertension are associated with reduced ACE2 expression,[15] indicating a plausible relationship between hypertension and COVID-19. As commonly used antihypertensive drugs, ACE inhibitors and angiotensin II receptor blockers can upregulate ACE2 expression while reducing blood pressure.[16,17] Therefore, antihypertensive drugs should be cautiously used in patients with COVID-19, and further studies are needed to establish the relationship between hypertension and COVID-19. Previous respiratory disease was significantly associated with death due to COVID-19 (P < .001), indicating that older patients with previous respiratory disease often have a poorer prognosis after infection with SARS CoV-2. Sex was statistically different in our univariate analysis, and older men exhibited a worse outcome than older women. Some studies indicated that SARS CoV-2 was more likely to infect males, which may be related to the high expression of ACE receptors in the lung tissues of Asian men. Other studies have suggested that the X chromosome and sex hormones may play a key role in the innate and adaptive immunity of female patients.[14,18] However, sex did not demonstrate a significant difference in the multivariate analysis in our study. Other risk factors may increase the probability of death in older men. The mean time from illness onset to hospital admission was 11 days in the two groups with different outcomes, which was also reported in another recent study.[13] Older patients who died were not denied treatment due to long wait times because there were enough wards and medical staff, which were the result of rapid actions of the government, the establishment of designated hospitals, and the national medical staff supporting Wuhan.

The present study had some limitations, the first of which was its retrospective design. More than one-third of patients did not have laboratory data for IL-6 and serum ferritin levels. Therefore, their roles may have been underestimated in predicting death during hospitalization. Second, the study did not include treatments such as antiviral and glucocorticoid therapy. Third, this was a single-center study from the Sino-French New City Branch of Tongji Hospital, which mainly admitted severe cases of COVID-19; as such, the results may be biased.

Current treatments for COVID-19 mainly include empirical antiviral drugs, rational glucocorticoid administration, and traditional Chinese medicine, which are effective in most patients. Currently, however, there is no proven effective drug for severely ill patients with COVID-19. Therefore, early identification of high-risk patients, stringent monitoring, and early intervention are needed to reduce mortality.

The COVID-19 outbreak has been declared a global pandemic. Internationally, the number of confirmed cases and deaths is increasing rapidly, which includes numerous older patients. This study found that older age and lower LYM count on admission indicated a poorer prognosis. These older patients need to be carefully monitored and administered suitable medical interventions to reduce their mortality.

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